2008

EVAR Safer Than Open AAA Repair
January 31, 2008—Marc L. Shermerhorn, MD, et al published a study in the New England Journal of Medicine that concluded that endovascular repair of abdominal aortic aneurysms (AAAs) is associated with lower short-term rates of death and complications compared with open repair (2008;358:464-474). The survival advantage is more durable among older patients. Late reinterventions related to AAA are more common after endovascular repair but are balanced by an increase in laparotomy-related reinterventions and hospitalizations after open surgery, the investigators found.

According to the investigators, randomized trials have shown reductions in perioperative mortality and morbidity rates with endovascular repair of AAAs, as compared with open surgical repair. Longer-term survival rates, however, were similar for the two procedures. There are currently no long-term, population-based data from the comparison of these strategies. Therefore, the investigators studied perioperative rates of death and complications, long-term survival, rupture, and reinterventions after open repair as compared with endovascular repair of AAAs in propensity score-matched cohorts of Medicare beneficiaries undergoing repair during the 2001-2004 period, with follow-up until 2005.

As detailed in the New England Journal of Medicine, there were 22,830 matched patients undergoing open repair of AAAs in each cohort. The average age of the patients was 76 years, and approximately 20% were women. The results showed that the perioperative mortality rate was lower after endovascular repair than after open repair (1.2% vs 4.8%; P<.001), and the reduction in mortality increased with age (2.1% difference for patients 67 to 69 years old vs 8.5% for those 85 years or older; P<.001). Late survival was similar in the two cohorts, although the survival curves did not converge until after 3 years. By 4 years, rupture was more likely in the endovascular-repair cohort than in the open-repair cohort (1.8% vs 0.5%; P<.001), as was reintervention related to AAA (9% vs 1.7%; P<.001), although most reinterventions were minor. In contrast, by 4 years, surgery for laparotomy-related complications was more likely among patients who had undergone open repair (9.7%, vs 4.1% among those who had undergone endovascular repair; P<.001), as was hospitalization without surgery for bowel obstruction or abdominal-wall hernia (14.2% vs 8.1%; P<.001).

Also in the New England Journal of Medicine, Professors Roger M. Greenhalgh, MD, and Janet T. Powell, MD, PhD, presented a case of an endovascular AAA repair that included a therapeutic recommendation, a discussion of the clinical problem, and the mechanism of benefit of this form of therapy (2008;358:494-501). Major clinical studies, the clinical use of this therapy, and potential adverse effects are reviewed. Relevant formal guidelines are presented, and clinical recommendations are suggested.

Cook's STARZ-TX2 1-Year TEVAR Data Published
January 28, 2008—In the Journal of Vascular Surgery, Jon S. Matsumura, MD, et al have published the 1-year results from the STARZ-TX2 trial of the Cook Medical's (Bloomington, IN) Zenith TX2 endovascular graft (2008;47:247-257). This trial evaluated the safety and effectiveness of thoracic endovascular aortic repair (TEVAR) with this contemporary endograft system compared with open surgical repair of descending thoracic aortic aneurysms and large ulcers.

In the study, 42 international trial sites enrolled 230 subjects with descending thoracic aortic aneurysms or ulcers. The study compared 160 TEVAR subjects treated with the Zenith TX2 with 70 open-repair subjects. Subjects were evaluated before the procedure, before discharge, at 1, 6, and 12 months, and annually for 5 years with medical examination, laboratory testing, chest radiographs, and CT scans. Mortality rates, prespecified severe morbidity composite index, major morbidity, clinical utility, aneurysm rupture, and secondary interventions were compared. The TEVAR subjects were evaluated by a core laboratory for device performance, including change in aneurysm size, endoleak, migration, and device integrity.

As detailed in the Journal of Vascular Surgery, the 30-day survival rate was noninferior (P<.01) for the TEVAR group compared with the open-repair group (98.1% vs 94.3%). The severe morbidity composite index was lower for TEVAR (0.2±0.7 vs 0.7±1.2; P<.01). Cumulative major morbidity scores were significantly lower at 30 days for the TEVAR group compared with the open-repair group (1.3±3 vs 2.9±3.6; P<.01). The TEVAR patients had fewer cardiovascular, pulmonary, and vascular adverse events, although neurologic events were not significantly different. Clinical utility for the TEVAR patients was superior to that of the open-repair patients. No ruptures or conversions occurred in the first year. Reintervention rates were similar in both groups. At 12 months, aneurysm growth was identified in 7.1% (8/112), endoleak in 3.9% (4/103), migration (>10 mm) in 2.8% (3/107), and other device issues were rare. None of the patients with migration experienced endoleak, aneurysm growth, or required a secondary intervention.

From these data, the investigators concluded that TEVAR with the TX2 is an effective and safer alternative to open surgical repair for treating anatomically suitable descending thoracic aortic aneurysms and ulcers at 1-year follow-up. Device performance issues are infrequent, but careful planning and regular follow-up with imaging remain a necessity.

On January 22, Cook Medical announced commencement of patient enrollment in the STABLE clinical trial to evaluate the Cook Zenith dissection endovascular system for treating type B thoracic aortic dissections. The system is composed of the new Cook Zenith dissection stent, used in conjunction with the Cook Zenith TX2 endovascular graft. The first patient found suitable for inclusion in the STABLE dissection clinical trial was a 60-year-old man diagnosed with a type B dissection of his thoracic aorta. He was treated with the Zenith dissection system. The TX2 stent graft repaired the primary entry tear. The bare-metal dissection stents were placed to expand and support the remainder of the dissected aorta for the length of the dissection, which, in this case, was to the level of the aortic bifurcation.

The Cook Zenith dissection endovascular system is intended for use in the endovascular treatment of descending thoracic aortic dissection in patients with anatomies appropriate for endovascular repair. The device's Z-stent exerts pressure that allows gradual apposition of the dissection septum and re-expansion of the true lumen, while not covering important arteries supplying the spinal cord with blood. The uncovered Zenith dissection stent is used to expand the true lumen in the distal thoracic aorta where preservation of the side branch artery blood flow is critical. In the US, the Cook Zenith dissection endovascular system is an investigational device not commercially available. The Cook Zenith TX2 endovascular graft is approved in Europe, Australia, and New Zealand for the treatment of thoracic aortic aneurysms and dissections.

Costs of Endovascular Coiling Compared to Surgical Clipping
January 1, 2008—In Stroke, Jane Wolstenholme, PhD, et al published a study in which investigators considered the treatment pathways, resource use, and costs of endovascular coiling versus surgical clipping after aneurysmal subarachnoid hemorrhage (2008;39:111-119). The investigators concluded that there is no significant difference in costs between the endovascular and neurosurgery groups at 12- or 24-month follow-up.

According to the investigators, the background of the study is the following: The International Subarachnoid Aneurysm Trial (ISAT) reported that endovascular coiling yields better clinical outcomes than surgical clipping at 1 year. The high cost of the consumables associated with the endovascular coiling procedure (particularly the coils) led health care purchasers to conclude that coiling was a more costly procedure overall. To examine this assumption and provide evidence for future policy, accurate and comprehensive data are required on the overall resource usage and cost of each strategy, the investigators stated.

In the study, the investigators provide detailed results of patient treatment pathways, resource utilization, and costs up to 24 months after randomization for endovascular and neurosurgical treatment of aneurysmal subarachnoid hemorrhage. Data are reported on costs related to initial and subsequent procedures (ward days, intensive care unit, equipment, staff, consumables, etc.), adverse events, complications, and follow-up. The data are based on a subsample of all patients randomized in ISAT, across 22 centers (n=1,644) in the UK. There was a nonsignificant difference of -£1,740 (-£3,582 to £32) in the total 12-month cost of treatment in favor of endovascular treatment. Endovascular patients had higher costs than neurosurgical patients for the initial procedure, for the number and length of stay of subsequent procedures, and for follow-up angiograms. However, these factors were more than offset by lower costs related to length of stay for the initial procedure. In the following 12- to 24-month period, costs for subsequent procedures, angiograms, complications, and adverse events were greater for the endovascular patients, reducing the difference in total per patient cost to -£1,228 (-£3,199 to £786) over the first 24 months of follow-up, reported the investigators.

Endovascular Treatment of TAAA Supported in JVS Study
January 2, 2008—A study by Timothy A.M. Chuter, MD, et al that assessed the role of multibranched stent grafts for thoracoabdominal aortic aneurysm (TAAA) repair was published in the Journal of Vascular Surgery (JVS). The investigators found that multibranched stent graft implantation eliminates aneurysm flow, preserves visceral perfusion, and avoids many of the physiologic stresses associated with other forms of repair. The results support an expanded role for this technique in the treatment of TAAA, the investigators concluded.

As detailed in JVS, the investigators used self-expanding covered stents to connect the caudally directed cuffs of an aortic stent graft with the visceral branches of a TAAA in 22 patients (16 men, 6 women) with a mean age of 76±7 years. All patients were unfit for open repair, and nine had undergone previous aortic surgery. Customized aortic stent grafts were inserted through surgically exposed femoral (n=16) or iliac (n=6) arteries. Covered stents were inserted through surgically exposed brachial arteries. Spinal catheters were used for cerebrospinal fluid pressure drainage in 22 patients and for spinal anesthesia in 11 patients. All 22 stent grafts and all 81 branches were deployed successfully. The results demonstrated that aortic coverage, as a percentage of subclavian-to-bifurcation distance, was 69%±20%. Mean contrast volume was 203 mL, mean blood loss was 714 mL, and mean hospital stay was 10.9 days. Two patients (9.1%) died perioperatively: one from guidewire injury to a renal arterial branch and the other from a medication error. Serious or potentially serious complications occurred in nine of 22 patients (41%). There was no paraplegia, renal failure, stroke, or myocardial infarction among the 20 surviving patients. Two patients (9.1%) underwent successful reintervention: one for localized intimal disruption and the other for aortic dissection, type I endoleak, and stenosis of the superior mesenteric artery. One patient had a type II endoleak. Follow-up was available for more than 1 month in 19 patients, more than 6 months in 12 patients, and more than 12 months in eight patients. One branch (renal artery) occluded for a 98.75% branch patency rate at 1 month. The other 80 branches remained patent. There were no signs of stent graft migration, component separation, or fracture, the investigators reported in JVS.

2007

Dynamic Cine-CT and MR Imaging Studied With EVAR
November 16, 2007—At the 34th Annual VEITH Symposium in New York City, Hence J.M. Verhagen, MD, presented findings from a study of the influence of the cardiac cycle on aortic configuration and diameter by using dynamic cine-CTA and MRA to observe the dynamics of acute dissections. The investigators also evaluated renal artery and aortic arch vessel movement. The investigators concluded that dynamic cine-CTA and MRA show insight into the dynamics of aortic disease and their endoluminal treatment that may improve the understanding of aortic pathology and be an important tool to improve stent graft design and treatment results.

According to Dr. Verhagen, CTA is the preferred modality for evaluation of aortic aneurysmal disease and dissections. Because CTA is used for endograft sizing and follow-up, it forms the basis of crucial endograft treatment decisions. The accuracy of measurements taken from CTA, however, is uncertain because they rely on static images of a dynamic process. The investigators' methods included pre- and postoperative measurements performed using electrocardiography-gated 64-slice CTA or dynamic MRA. Changes were measured in transverse aortic sections at different relevant levels. Center-of-mass displacement of the renal arteries and aortic arch vessels was determined per heartbeat. Data were analyzed using image segmentation software (DynamiX, Image Sciences Institute, Utrecht, The Netherlands). Differences were compared with p2 .05 significance.

Dr. Verhagen stated that the results of the dynamic cine-CTA and MRA demonstrated significant aortic diameter changes during the cardiac cycle both before and after endovascular aneurysm repair (EVAR) at all levels (mean 8.9%–11.5%; P<.001 for all levels). The investigators found that EVAR had no effect on changes in the aortic area and diameter. Cardiac-induced preoperative renal artery motion was up to 3 mm and was unchanged after either endograft treatment. Fenestrated EVAR with the placement of renal stents almost abolishes renal artery motion (.3 mm; SD, .1; range, .2–.5 mm; p2 .01). Dynamic imaging gave relevant insight in acute dissections and arch vessel movement and showed that the aorta is a truly dynamic environment, said Dr. Verhagen.

Medtronic Announces 5-Year Clinical Data for AneuRx
October 2, 2007—Medtronic CardioVascular, Endovascular Innovations (Santa Rosa, CA) announced the release of its fourth edition of the AneuRx Clinical Update, representing the largest collection of clinical data available for any commercially approved endograft. The update includes data on more than 1,000 patients in its clinical trial and 70,000 implants since 1996. The Clinical Update was distributed to more than 18,000 physicians worldwide as an insert in the September 2007 issue of Endovascular Today and is also on the AneuRx section of the company's Web site, www.medtronic.com.

According to the company, a principal component of the Clinical Update is newly released long-term data from the AneuRx IDE (investigational device exemption) clinical trial, which included 1,193 patients treated with an early generation of the AneuRx device. Of the more than 600 patients in the trial, 96% were free from an aneurysm-related death at 5 years of follow-up. In collaboration with the FDA, Medtronic also analyzed aneurysm-related death using a broader FDA definition, and the analysis showed a freedom from aneurysm-related death at 5 years of 94.6%. Between 4 and 5 years of follow-up, there was an observed increase in aneurysm-related death. Factors that were associated with late aneurysm-related death include, but are not limited to, poor follow-up, patients refusing treatment, and an elderly patient population. These data show the continued safety and efficacy of this device, taking into consideration early-generation endograft designs, the physician learning curve for implantation technique, and liberal patient selection criteria, the company stated.

In addition to the updated IDE clinical trial results, Medtronic also reported on the AneuRx Postmarket Surveillance Registry and the Lifeline Registry of Endovascular Aneurysm Repair, both of which provide contemporary, real-world usage data on the AneuRx stent graft. In the Postmarket Surveillance Registry, at 3 years, patients experienced freedom from aneurysm rupture of 99% and freedom from surgical conversion of 96%. The incidence of migration in both registries consisted of a single report of migration out of a 334-patient cohort, representing a migration rate of .3% at 3 years, according to Medtronic. Other key areas highlighted in the Clinical Update include information on endoleaks, migration, and the related critical importance of appropriate patient follow-up for successful long-term outcomes, the company stated.

Obesity Linked to Risk of AAA
October 29, 2007—A study by Jonathan Golledge, MD, et al investigated the association between anthropometric measures of obesity, serum adipokines, and abdominal aortic aneurysm (AAA), noting that obesity is associated with occlusive artery disease but is not considered a risk factor for AAA. The investigators concluded that measures of obesity are independently associated with AAA. Serum resistin concentrations were more strongly associated with aortic diameter than adipokines, which are more intimately associated with adiposity. Further studies are required to investigate the mechanisms linking resistin and AAA, the investigators stated. The study will be published in Circulation and is available online at circ.ahajournals.org.

As detailed in Circulation, the investigators screened 12,203 men 65 to 83 years of age for AAA using ultrasound, as part of a population study. Of those men, 875 had an AAA (≥30 mm). Cardiovascular risk factors and waist and hip circumference were recorded. Serum adipokines were measured in 952 men, 318 of whom had an AAA. Waist circumference (odds ratio [OR], 1.14; 95% confidence interval [CI], 1.06–1.22) and waist-to-hip ratio (OR, 1.22; 95% CI, 1.09–1.37) were independently associated with AAA after adjustment for other known risk factors. The association was stronger for AAA ≥40 mm (waist-to-hip ratio: OR, 1.53; 95% CI, 1.26–1.85). Serum resistin concentration was strongly independently associated with AAA (OR, 1.53; 95% CI, 1.32–1.76) and aortic diameter (β=.19, P<.0001). Serum adiponectin was associated with AAA ≥30 mm (OR, 1.26; 95% CI, 1.07–1.50) but not AAA ≥40 mm (OR, 1.03; 95% CI, .77–1.39). Serum leptin was not associated with AAA, the investigators reported in Circulation.

Endologix's Visiflex Used With Powerlink in AAA Treatment
October 3, 2007—Endologix, Inc. (Irvine, CA) announced the first procedures using the company's Powerlink system with its Visiflex Integrated System (IS) for the minimally invasive treatment of abdominal aortic aneurysms. The first seven procedures using the Visiflex IS were performed at Southern Clinic in Nuremberg, Germany; Imelda Hospital in Bonheiden, Belgium; St. Joseph Hospital in Marseille, France; and the Wilhelminenspital in Vienna, Austria. The Powerlink with Visiflex IS has received CE Mark approval for sale in the European Union, but it is not approved for sale in the US, the company advised.

According to the company, the Visiflex IS is the company's third-generation delivery system. It is designed to simplify endoluminal stent graft deployment and catheter withdrawal by eliminating the front sheath. The single-sheath design provides easier insertion through challenging iliac anatomy and allows interventionists to treat a broader spectrum of patients. The Visiflex IS uses the Powerlink's outer sleeve as a 19-F hemostatic introducer sheath to act as a conduit for adjunctive procedures and eliminates catheter exchanges, the company stated.

Abbott's ProGlide Shows Success in Percutaneous Access
May 30, 2007—The Society for Vascular Surgery announced that a study in the Journal for Vascular Surgery reports that totally percutaneous access for endovascular abdominal aorta repairs (EVAR) and thoracic endovascular aorta repairs (TEVAR) are safe and feasible using the Perclose ProGlide device (Abbott Vascular, Redwood City, CA) (2007;45:1095-1101). Investigators from the Division of Vascular Surgery and Endovascular Therapy at the University of Florida in Gainesville noted that the ProGlide with larger sheaths in a select group of patients showed a higher technical success rate (94.6%) than historically reported when using Abbott Vascular's Prostar XL device.

Between December 2004 and August 2006, 262 EVAR procedures were performed with percutaneous access. The technique involved deployment of two ProGlide devices before sheath insertion with the sutures left extracorporeally for closure after the procedure ("preclose technique"). A total of 559 ProGlide devices were used to close 279 femoral arteries. Of those, 175 femoral arteries required insertion of 18-F to 24-F sheaths (6.7-mm to 8.6-mm outer diameter). For EVAR and TEVAR procedures, the success rates when using 12-F to 16-F sheaths were higher than for the 18-F to 24-F sheaths (99% vs 91.4%). The preclose technique also resulted in shorter overall procedure times as compared to a similar cohort using open femoral exposures (EVAR, 115 vs 128; TEVAR, 80 vs 112).

LeMaitre Vascular to Begin UNITE Trial of UniFit AAA Stent
June 12, 2007—LeMaitre Vascular, Inc. (Burlington, MA) announced the enrollment of the first patient in the UNITE aorto-uni-iliac stent graft clinical trial, a pivotal study to evaluate the safety and effectiveness of the UniFit abdominal stent graft in the treatment of aorto, aorto-iliac, and iliac aneurysms. The endovascular procedure was conducted at Emory University in Atlanta, Georgia. The company announced on May 9 that the FDA granted an IDE supplement to conduct the trial.

According to the company, UNITE will enroll 90 patients in up to 14 centers who will be followed for at least 1 year before LeMaitre's premarket approval application to the FDA. The primary effectiveness endpoint of the study is based on aneurysm exclusion as evaluated through 1-year follow-up. The UNITE study compares the safety and efficacy of the UniFit against open-surgical abdominal aorta aneurysm repair, the company stated.

The UniFit, which is commercially available in the European Union, features a single-bodied, encapsulated design to prevent its stents from touching the vessel wall and allows a wider range of stent graft sizes. The company noted that the FDA's IDE approval applies only to the investigational use of UniFit stent grafts that have been sterilized with ethylene oxide gas. UniFit devices sold outside the US are sterilized with hydrogen peroxide, a newer and generally faster means of sterilizing medical devices that enables more rapid production of customized stent grafts, according to the company. LeMaitre Vascular stated that it is working with the FDA to resolve questions regarding this method of sterilization with the intent of seeking a premarket approval for UniFit systems processed in the manner.

Medtronic Talent's 12-Month VALOR Data Presented at SVS
June 8, 2007—Medtronic, Inc. (Minneapolis, MN) announced that Ronald M. Fairman, MD, Principal Investigator for the VALOR (Evaluation of the Medtronic Vascular Talent Thoracic Stent Graft System for the Treatment of Thoracic Aortic Aneurysms) clinical study, presented positive 12-month results for the study at the 61st Annual Meeting of the Society for Vascular Surgery in Baltimore, Maryland. VALOR is evaluating the company's Talent thoracic stent graft system in a prospective, multicenter study of 195 test group patients with thoracic aortic aneurysms who were considered candidates for open surgical repair. The primary endpoint is all-cause mortality at 12 months, comparing endovascular stent graft treatment to a historical surgical control group.

According to Medtronic, Dr. Fairman reported that patients in the test group who received the Talent thoracic stent graft had a statistically significant reduction in all-cause mortality (16.1% vs 29.8% in the control group; P<.001), using literature-derived figures for the open surgery group. Aneurysm-related mortality in the VALOR trial was 3.1% at 12 months. The Talent thoracic system also had a successful aneurysm treatment rate of 89.2%, defined as no aneurysm growth >5 mm between 1 and 12 months and the absence of a type 1 endoleak. The Talent system demonstrated 100% patency with a 99.5% deployment success rate. The Talent features a wide range of sizes, with 22-mm to 46-mm diameters, allowing the therapy to be available to a greater number of patients. In March 2007, Medtronic submitted a premarket approval application to the FDA based on the VALOR data and is awaiting approval. The Talent has been available outside the US since 1998.

In other company news, Medtronic reported that Rudy Boesch, the oldest participant in the reality television series Survivor, has survived another challenge. The former US Navy Seal, who at age 79 competed with people half his age for 6 weeks on the island of Borneo, was diagnosed with an abdominal aortic aneurysm (AAA). The AAA was detected in an x-ray of Mr. Boesch's back, which he injured while weightlifting. He went to vascular surgeon Richard DeMasi, MD, for an endovascular implantation of a Medtronic AneuRx AAA stent graft. Mr. Boesch resumed exercising in 6 weeks and has completely recovered. He and his wife will compete in the racquetball event in the 2007 Summer National Senior Olympic Games. Medtronic, a charter member of the National Aneurysm Alliance, is highlighting Mr. Boesch's experience to increase public awareness of the importance of AAA screening. Since 2004, the National Aneurysm Alliance has provided more than 31,000 screenings, in which approximately 600 AAAs have been detected.

Data for Cook's STARZ-TX2 TEVAR Study Presented at SVS
June 9, 2007—Jon S. Matsumura, MD, et al presented early results of STARZ-TX2, a clinical trial to evaluate thoracic endovascular aortic repair (TEVAR) in the elective treatment of patients with descending thoracic aortic aneurysms or ulcers. The presentation was made at the 61st Annual Meeting of the Society for Vascular Surgery in Baltimore, Maryland. STARZ-TX2 is an international, nonrandomized, controlled trial comparing the safety and effectiveness of open-surgical repair (control) with TEVAR using the Zenith TX2 TAA (thoracic aortic aneurysm) endovascular graft (Cook Medical, Bloomington, IN). The Zenith TX2 features a modular system of tubular components constructed of self-expanding, stainless steel Z-stents sewn to full-thickness woven polyester fabric. In the trial, 160 TEVAR patients and 70 control patients were enrolled at 42 medical centers between March 2004 and July 2006.

According to the investigators, 72% of TEVAR subjects and 60% of controls were male. Mean age was 72 years for the TEVAR group and 68 years for the control group. Two patients in the TEVAR group did not receive the device due to access concerns. Clinical utility measures were markedly superior in the TEVAR group compared to the control group (ie, intraoperative red blood cell transfusion [TEVAR 3%, control 87%] and days to hospital discharge [TEVAR 5±9 days, control 16±19 days]). After 30 days, perioperative mortality was lower in the TEVAR group compared to the control group (1.9% vs 5.7%), and sentinel perioperative major morbidity events were lower in the TEVAR group compared to controls: stroke (2.5% vs 7.1%), paraplegia (1.3% vs 5.7%), and renal failure requiring dialysis (1.3% vs 4.3%). Through 30 days, secondary interventions were performed on three TEVAR patients and three control patients. There were no aneurysm ruptures in either group, and there were no conversions to open repair in the TEVAR group. Also, preliminary 1-year data presented at the meeting included a 1-year survival rate of 92% in the TEVAR cohort.

The STARZ-TX2 investigators concluded that preliminary 30-day results of this trial suggest that TEVAR has mortality, major morbidity, and clinical utility that compare favorably to open repair, with no ruptures in either group, and no conversions in the TEVAR group, the investigators stated. Analysis of the 12 month data is almost completed and will be submitted for peer review, the investigators stated.

TEVAR With Gore TAG Studied in Complex Pathology
June 7, 2007—At the 61st Annual Meeting of Society for Vascular Surgery (SVS) in Baltimore, Maryland, Richard P. Cambria, MD, et al, presented data from a prospective study designed to evaluate the use of the Gore TAG (Gore & Associates, Flagstaff, AZ) thoracic endoprosthesis for the thoracic endovascular aneurysm repair (TEVAR) of thoracic aortic rupture (TAR), acute complicated type B dissections (AD), and traumatic aortic tear (TAT) at 14 academic medical centers. The investigators concluded that the preliminary data suggest the utility of TEVAR for life-threatening complex thoracic aortic pathology wherein conventional surgical treatment has traditionally been accompanied by excess mortality and/or paraplegia. Further analysis is underway.

From August 2005 to February 2007, the trial enrolled 59 patients (20 TAR/19 AD/20 TAT). Thirty-day outcomes were available. The investigators reported that demographic/clinical data included that 80% of patients were male, with median age of 66 years, but differed widely as function of pathology (80 years for TAR but 53 years for AD/TAT). Mean injury stroke scale (ISS) in TAT patients was 36, and mean SVS risk score was highest (7.6±5.6) in TAR patients. There were no arterial access or deployment failures. Thirty-day composite death/paraplegia occurred in eight of 59 (13.6%) patients with a single paraplegia event (1.7% overall) in a TAT patient; six (10.2%) patients experienced reversible paraparesis. Of the six patients, three died without known recovery from paraparesis, two recovered, and one was ongoing, although this patient had no motor function assessment before treatment.

Thirty-day mortality was 5% for TAT, but in the 15% range for both TAR/AD. American Society of Anesthesiologists class was the sole independent predictor of mortality/paraplegia (odds ratio, 4; 95% confidence interval, 1.3-18). Procedural deployment-related adverse events occurred in seven (11.9%) patients and included two instances of extension of AD. Device-related adverse events through 30-day follow-up occurred in eleven (18.6%) patients: rupture in two AD patients, graft infection (presented with infection, but not confirmed until after treatment) in one TAR patient, graft collapse in two TAT patients and major endoleak in six patients; three (5% overall) of these underwent explant/open conversion. Four reinterventions with TEVAR were performed: three for endoleak and one for persistent aortic dissection, the investigators reported.

Cordis Neurovascular's Enterprise Granted HDE to Treat Intracranial Aneurysms
May 10, 2007—Cordis Neurovascular, Inc., (a division of Cordis Corporation, a Johnson & Johnson company, Miami, FL) announced that the FDA has granted Humanitarian Device Exemption (HDE) approval for the Cordis Enterprise vascular reconstruction device and delivery system for use with embolic coils in the treatment of wide-neck intracranial aneurysms. The Enterprise is a self-expanding nitinol stent with a closed-cell design. It is available in the US for use in patients with hard-to-treat aneurysms selected for endovascular neurointervention. Specifically, the stent is approved to treat wide-neck, intracranial, saccular, or fusiform aneurysms arising from a parent vessel with a diameter ≥3 mm and ≤4 mm. The clinical outcomes from the Cordis Enterprise Vascular Reconstruction Device Study, which enrolled patients in Europe and the US, were assessed by an independent core lab. Data from the independently evaluated clinical study suggest that the Enterprise is a promising assist device for the treatment of aneurysms, but the device's effectiveness for this use has not been demonstrated, the company noted.

ev3's Onyx HD 500 Liquid Embolic System Receives HDE to Treat Cerebral Aneurysms
April 16, 2007—ev3 Inc. (Plymouth, MN) announces that it has received an FDA Humanitarian Device Exemption (HDE) approval for the Onyx HD 500 liquid embolic system for the treatment of intracranial aneurysms. The HDE allows ev3 to market the Onyx for use in patients with wide-necked cerebral aneurysms. The HDE is limited to saccular, sidewall aneurysms with dome-to-neck ratios of <2 mm that are not amenable to treatment with surgical clipping. In July 2005, the Onyx 18 and 24 systems received FDA approval for the treatment of cerebral arteriovenous malformations.

According to the company, marketing of the Onyx HD 500 will be preceded by a lengthy period of education and training of a small group of leading neurovascular specialists. Once trained, this group of proctors will help ensure that the use of Onyx HD 500 is carefully controlled as is required for all HDE-approved devices. A US Investigational Device Exemption study and two European clinical studies examined approximately 200 patients with wide-necked aneurysms who were effectively treated with the Onyx HD 500. Wide-necked aneurysms occur in approximately 20% of the 17,000 patients who are treated with embolic coils each year in the US, the company stated.

MicroVention's HELPS Trial Completes Enrollment
April 5, 2007—MicroVention, Inc. (Aliso Viejo, CA) announced today the completion of enrollment in an independent, physician-designed and -managed, international trial of the company's HydroCoil embolization system for treating cerebral aneurysms.

According to the company, HELPS (HydroCoil Endovascular Aneurysm Occlusion and Packing Study) is a head-to-head prospective, blinded, randomized trial that compares the results of the HydroCoil system to results from approved bare-platinum coils. The trial is managed by the Lothian Health Board with initial support from the UK's National Health Service. The trial enrolled 500 patients at 24 medical centers from Scotland, England, Wales, Germany, France, Australia, Brazil, Northern Ireland, Argentina, and the US. The study's Chief Investigator is Philip White, MD, of Western General Hospital in Edinburgh, Scotland. Dr. White will present unblinded safety data and initial angiographic procedural data at the World Federation of Interventional and Therapeutic Neuroradiology meeting in Beijing in September 2007. The HydroCoil embolic system combines platinum microcoil technology with the company's Intelligel polymer, an expandable microporous hydrogel. MicroVention, which merged with Terumo Corporation (Somerset, NJ) in 2006, has received 510(k) clearance and CE Mark approval for the HydroCoil.

Boston Scientific Commences MAPS Brain Aneurysm Trial
April 2, 2007—Boston Scientific Corporation (Natick, MA) announced the commencement of enrollment in the company's MAPS (Matrix And Platinum Science) clinical trial. The MAPS trial is designed to identify and investigate clinically relevant endpoints for evaluating the efficacy and durability of endovascular treatment of brain aneurysms. Patients will be randomized to receive either Matrix2 detachable coils or GDC detachable coils. Boston Scientific manufactures both the GDC coils, which are bare-platinum detachable coils that are cleared for aneurysm treatment and the Matrix2 coils, which are covered with a polyglycolic-polylactic acid biopolymer shown to improve treatment durability in preclinical studies, the company stated.

According to the company, MAPS is a prospective, multicenter study that will randomize approximately 630 patients at 50 global centers for treatment of brain aneurysms. The trial's primary endpoint is target aneurysm recurrence, a composite of target aneurysm reintervention, target aneurysm rupture or rerupture, or death. The first patient was enrolled and treated by Michael Madison, MD, and James Goddard, MD, at the Healtheast Neurovascular Institute of St. Joseph's Hospital in St. Paul, Minnesota.

"Not only is this trial important in its own right, but it further demonstrates that multidisciplinary aneurysm trials can and will help define the future of aneurysm treatment," commented MAPS Co-Principal Investigator Cameron McDougall, MD, Chief of Endovascular Neurosurgery, at the Barrow Neurological Institute in Phoenix, Arizona.

Data Presented on Endologix Powerlink in Difficult AAAs
February 12, 2007—Endologix, Inc. (Irvine, CA) announced that favorable data presented at the International Congress XX on Endovascular Interventions (ICEI) supports the use of the company's Powerlink system in patients with anatomies considered difficult to treat with traditional endoluminal stent grafts (ELGs). The data include 5-year patient follow-up data from the Powerlink system pivotal clinical trial.

The Powerlink was featured in three presentations at ICEI, which was held February 9-15, 2007 in Scottsdale, Arizona. According to the company, "Secondary Intervention in Unfavorable AAA Neck Anatomy," an abstract presented by John T. Collins, MD, included core lab-reviewed data demonstrating the Powerlink's ability to effectively treat patients with reverse-tapered neck anatomies. Of the 50 patients in the Powerlink pivotal clinical trial identified with reverse-tapered aortic necks, no secondary procedures were required for migration or proximal type 1 endoleaks through a mean follow-up of 40.2 months (range, 1 to 64 months).

A second presentation, "New Approach to Prevent Distal Migration and Rupture in EVAR: Anatomical Fixation," by Dieter Raithel, MD, highlighted data from 378 patients treated during 7 years with the Powerlink. The data demonstrate the long-term efficacy of an implant strategy of anatomical fixation to place the Powerlink stent graft on the aortic bifurcation, which allows for treating anatomies previously unsuitable for endovascular aneurysm repair (EVAR).

The third presentation, "Results of EVAR for Small vs Large Aneurysms," by Jeffrey Carpenter, MD, discussed 5-year follow-up data from the pivotal study that indicate that patients with larger aneurysms treated with the Powerlink system had no greater incidence of major adverse events, secondary procedures, or endoleaks than those with smaller aneurysms. Dr. Carpenter noted that there were no aneurysm ruptures, no graft material failures, and no stent fractures through the 5-year follow-up period. These results demonstrated the device's durability, the company stated.

APEX Study of CardioMEMS EndoSure Published in JVS
January 29, 2007—Takao Ohki, MD, PhD, et al have published the initial results from the APEX trial (Acute Pressure Measurement to Confirm Aneurysm Sac EXclusion) trial in the Journal of Vascular Surgery (2007;2:227-235). The results were first presented at the 59th annual meeting of the Society for Vascular Surgery held in Chicago on June 16-19, 2005.

APEX is a prospective, multicenter, international trial sponsored by CardioMEMS, Inc. (Atlanta, GA), to evaluate the safety and efficacy of the company's EndoSure wireless pressure sensor for endovascular repair (EVAR). The EndoSure has been developed and tested in a clinical setting to increase its efficacy and safety for intraoperative endoleak detection. The investigators concluded that implantation of the wireless pressure sensor is safe, and remote aneurysm sac pressure sensing is feasible. It was a valuable guide in evaluating the completeness of the EVAR procedure. Long-term study will be needed to prove its efficacy for postoperative surveillance, the investigators stated.

According to the investigators, complete exclusion and depressurization of the aneurysm sac is the prime goal of EVAR of abdominal aortic aneurysms. Thus, any EVAR that results in a type 1 or 3 endoleak has been classified as a technical failure. The current method to detect endoleaks uses intraoperative aortography, which is limited by its subjective nature, inability to quantify the significance of the endoleak, and artifacts such as bowel gas that may mimic an endoleak. In addition, repetitive contrast injection may impair renal function, the investigators stated.

As detailed in the Journal of Vascular Surgery, the 30-mm X 5-mm X 1.5-mm sensor contains no battery and is powered externally with radiofrequency energy. The sensors are extremely stable, operate over the full physiologic range of pressures, and have a resolution of 1 mm Hg. Ninety patients, 76 of whom were eligible for analysis, were enrolled at 12 sites. The sensor was implanted via the contralateral femoral artery at the time of EVAR. The sac pulse pressure was measured with both an angiographic catheter and the sensor after deployment of the main endograft but before the deployment of the contralateral limb (type 1 endoleak equivalent). Sac pressure was again measured with the sensor after deployment of the contralateral limb and completion of the EVAR. Data were collected in a prospective manner. The investigators found that in all of the eligible patients (n=76), the initial sensor pressure measurement agreed closely with the angiographic catheter pressure measurement of the type 1 endoleak equivalent. At the completion of the procedure, there was agreement between the sensor measurement and angiography regarding the presence or absence of a type 1 or 3 endoleak in 92.1% (n=70) of the measurements. The sensitivity was 94%, and the specificity was 80% for detecting type 1 or 3 endoleaks. Final pulse pressures decreased significantly compared with baseline measurements.

"This trial demonstrates that this wireless sensor for aneurysm sac measurement is safe and feasible, and can be used to diagnose the location and type of endoleak during endovascular aneurysm repair," commented Dr. Ohki. Dr. Ohki noted that the APEX data were instrumental in the FDA approval of the EndoSure device, which is now commercially available for stent graft implantation procedures. Future studies will focus on using sac pressure monitoring as an alternative to computed tomography for long-term aneurysm surveillance.

Excellent Results Shown for EVAR of High-Risk AAAs
January 29, 2007—In the Journal of Vascular Surgery, Ruth L. Bush, MD, MPH, et al published a study of veterans who were deemed high risk for surgical therapy for the treatment abdominal aortic aneurysms (AAAs) (2007;2:227-235). The study found that outcomes after elective endovascular repair (EVAR) of AAAs are excellent and that the procedure is relatively safe in this special patient population. The retrospective data demonstrated that patients with considerable medical comorbidities and infrarenal AAAs benefit from and should be considered for primary EVAR.

According to the investigators, recent results after AAA EVAR have raised questions of its value in patients deemed at high risk for surgical intervention. The National Surgical Quality Improvement Program (NSQIP) of the Department of Veteran Affairs (VA) is the largest prospectively collected and validated US surgical database representing current clinical practice. The study's purpose was to evaluate outcomes after elective EVAR performed in high-risk veterans. Using NSQIP data from 123 participating VA hospitals, the investigators retrospectively evaluated patients who underwent elective aneurysm repair from May 2001 to December 2004. High-risk criteria were used to identify a cohort for analysis (EVAR, n=788; open, n=1580). High-risk criteria analyzed included age ≥60 years, American Society of Anesthesiology (ASA) classification 3 or 4, and the comorbidity variables of history of cardiac, respiratory, or hepatic disease, cardiac revascularization, renal insufficiency, and low serum albumin level. The primary end points were 30-day and 1-year all-cause mortality, and a secondary end point of perioperative complications was evaluated. Statistical analysis included univariate analysis and multivariate modeling.

As detailed in the Journal of Vascular Surgery, veterans who were classified as high risk underwent elective EVAR with significantly lower 30-day (3.4% vs 5.2%, P=.047) and 1-year all-cause mortality (9.5% vs 12.4%, P=.038) than patients having open repair. EVAR was associated with a decrease in 30-day postoperative mortality (adjusted odds ratio [OR], 0.65; 95% confidence interval [CI], 0.42 to 1.03; P=.067) as well as 1-year mortality (adjusted OR, 0.68; 95% CI, 0.51 to 0.91; P=.0094) despite the presence of severe comorbid conditions. The risk of perioperative complications was significantly lower after EVAR (16.2% vs 31%; P<.0001; adjusted OR, 0.41; 95% CI, 0.33 to 0.52; P<.0001). A subset analysis of higher-risk patients (ASA 4 and the above comorbidity variables) still demonstrated an acceptable 30-day mortality rate, the investigators reported.

Japan Grants Preliminary Reimbursement for AAA EVAR
January 18, 2007—Cook Medical (Bloomington, IN) announced that preliminary hospital reimbursement for endovascular repair of abdominal aortic aneurysms (AAAs) has been granted in Japan, where the company's Zenith AAA stent graft is approved for sale. Cook expects full reimbursement in March 2007, which will precipitate a complete rollout of the Zenith stent graft system in the country with its Japanese distributor, Medico's Hirata Co. Ltd. (Osaka, Japan). Hirata's approval was granted on July 11, 2006, under the Japanese Pharmaceutical Affairs Law. The Zenith endograft will be re-examined 3 years after the approval date. A requirement of approval includes providing detailed clinical training to Japanese physicians to ensure their safe and effective use of the device. The device has a 9-year history of successful use in Europe and a 7-year history in the US, Cook stated.

Gore Excluder Approved in Japan for AAA Treatment
January 30, 2007—Gore & Associates (Flagstaff, AZ) announced that the Japanese Pharmaceuticals and Medical Device Agency granted Shonin regulatory clearance for the company to market the Gore Excluder abdominal aortic aneurysm (AAA) endoprosthesis in Japan. The Gore Excluder is indicated for the endovascular treatment of AAAs. Gore also stated that it recently launched a new patient education resource intended to help provide the public with information about the causes, symptoms, and available treatments for AAAs. The resource, part of broader content and feature improvements to www.goremedical.com, guides visitors through a television-like experience that addresses questions and concerns commonly raised by those affected by AAAs.

2006

VALOR II and VIRTUE Study Medtronic's Valiant Stent Graft; Talent's VALOR Data Presented
December 15, 2006–Medtronic Vascular (Santa Rosa, CA) announced the first patient enrollments of two separate clinical trials, VALOR II and VIRTUE, as well preliminary results from the VALOR trial.

Joseph Bavaria, MD, of the University of Pennsylvania, enrolled the first patient in the VALOR II clinical trial, which will examine the safety and efficacy of Medtronic's Valiant stent graft in treating descending thoracic aortic aneurysms. The trial will enroll a maximum of 125 patients at up to 30 investigational sites in the US. The company anticipates that the data from VALOR II will be used to support a product approval application to the FDA. The national principal investigator for VALOR II is Ronald Fairman, MD, of the University of Pennsylvania.

Ivan Degrieck, MD, of the Onze-Lieve-Vrouw Hospital in Aalst, Belgium, enrolled the first patient in the VIRTUE registry. VIRTUE will enroll 100 patients at approximately 20 clinical centers in Western Europe to evaluate the use of the Valiant graft for the treatment of descending thoracic aortic dissections, known as type B dissections. According to the company, the objective of the VIRTUE registry is to collect additional data on the health economics and the clinical performance of Valiant for the treatment of acute dissections, complicated or expanding subacute dissections, and expanding chronic dissections. The VIRTUE registry's Principal Investigator is Prof. Matt Thompson, MD, of St. George's Hospital at the University of London. The Valiant stent graft has been available outside the US since 2005 for the treatment of thoracic aortic aneurysm, dissections, and other lesions.

On November 16, 2006, at a satellite event at the VEITH Symposium in New York City, Dr. Fairman presented 12-month safety endpoint data from the VALOR trial's test arm. The results met the primary safety endpoint for the trial. Based on the data, Medtronic Vascular would be filing for FDA approval of the Talent thoracic stent graft, stated Dr. Fairman.

The VALOR trial is a prospective, nonrandomized, multicenter, consecutive trial enrolling subjects into three study arms (test, registry, and high-risk). The objective of the test arm was to evaluate the safety and efficacy of the Talent thoracic stent graft system for patients with thoracic aortic aneurysm who are considered candidates for open surgical repair and are low-to-moderate risk, per modified SVS/AAVS criteria (categories 0, 1, or 2).

The primary safety endpoint of the VALOR test arm was all-cause mortality at 12 months (hypothesis: superiority of the VALOR test arm to a literature control of 30%); the primary efficacy endpoint was successful aneurysm treatment at the 12-month follow-up visit. Of the 195 patients entered into the test arm, 59% were male, and the mean age was 70.2 years. Most were considered SVS risk class 2 (72.8%), with 21% considered class 1. At 12 months, the all-cause mortality rate before the 12-month visit was 16.1% (31/193), with a confidence interval of 11.2% to 22%, Dr. Fairman reported.

Cook's Z-Trak Introduction System Receives CE Mark
December 4, 2006–Cook Medical (Bloomington, IN) announced CE Mark approval for the Z-Trak introduction system for its Zenith TX2 thoracic aortic aneurysm (TAA) endovascular stent graft. According to the company, by utilizing a hydrophilic-coated Cook Flexor sheath and superelastic alloy inner cannula, the Z-Trak Plus system is designed to provide enhanced precision and flexibility of entry and tracking well into the aortic arch. The Flexor sheath features kink-resistant tubing technology for superior flexibility, and a low coefficient of friction during use. Combining the Cook Flexor's capabilities with the Z-Trak delivery system allows the interventionist to navigate the aortic arch more easily to deliver the stent graft to the precise treatment location. The device's trackability and maneuverability provide precise, controllable device orientation and deployment of the Cook TAA stent graft, the company stated.

Cook's Zenith TX2 TAA endovascular graft is indicated for treatment of descending thoracic aortic aneurysm and type B aortic dissection. The TX2 is reinforced with self-expanding stainless steel Z-stents. It features circumferentially anchoring barbs on both the proximal and distal segments of the device, which provides superior fixation. Radial force from the self-expanding Z-stents allows the graft to provide an excellent seal within the patient's aorta. The Zenith TX2's US trial results will be submitted soon to the FDA for US market approval, the company stated.

"Packaging such a stent into a low-profile delivery system, which can negotiate the potential tortuosity of the iliacs, infrarenal aorta, and distal thoracic aorta and yet retain accurate deployment characteristics is vital when there is no room for error," commented Michael P. Jenkins, MD, of St. Mary's Hospital, London, UK. "I believe the Cook TX2 has made significant advances towards these goals."

Lombard's Refix Endostapler Earns CE Mark Approval
November 10, 2006–Lombard Medical Technologies PLC (Boston, MA) announced that it has received CE Mark approval for the Refix Endostapler. According to the company, the Refix has been initially designed to provide increased fixation of endovascular stent grafts to treat abdominal and thoracic aortic aneurysm. The device percutaneously delivers tiny fasteners (staples), which are pushed through both the wall of the stent graft and the wall of the aorta, to keep the stent graft firmly in place and prevent it from migrating, thus reducing the risk of endoleaks. In the US, Lombard Medical is seeking an IDE for Refix with an investigational study targeted to begin in early 2007, subject to FDA consent, the company stated.

Endologix's Powerlink 5-Year Follow-Up Data Presented
October 23, 2006–Endologix, Inc. (Irvine, CA) announced that Rodney A. White, MD, presented 5-year follow-up data on the Powerlink System pivotal clinical trial for the treatment of abdominal aortic aneurysm (AAA) at the 18th annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium in Washington, DC. According to the company, the data demonstrated that 97.9% of patients were free from AAA mortality; there were no aneurysm ruptures; there were no stent or graft material failures; and 86.6% of patients were free from device-related secondary procedures.

"The clinical data for the Powerlink System is compelling," commented Dr. White. "Endologix has set the bar as it pertains to the durability of the pivotal trial data set, with a 95% compliance of eligible patient follow-up at 5 years as well as core lab 3-D modeling."

Endologix Launches Visiflex Delivery System for AAA Treatment
October 2, 2006–Endologix Inc. (Irvine, CA) announced the US launch of its next-generation Visiflex delivery system for the deployment of the Powerlink endoluminal stent graft in the endovascular treatment of abdominal aortic aneurysms. The Visiflex received FDA approval in May 2006, and a limited strategic release was initiated for physician preference testing prior to the full launch this fall. According to the company, the Visiflex's new design improves delivery of the system by facilitating smoother insertion and withdrawal of the delivery catheter. The device also improves visibility under fluoroscopy while deploying the stent graft.

First US Procedure Performed With Aptus AAA System
July 24, 2006–Georgetown University Hospital announced that David H. Deaton, MD, Chief of Endovascular Surgery, performed the first procedure in the US using the Aptus AAA Repair System (Aptus Endosystems, Inc., Sunnyvale, CA). The Aptus system is an endovascular graft for the repair of an abdominal aortic aneurysm (AAA). The patient is the first to be enrolled in the FDA-sanctioned clinical trial designed to demonstrate the safety and efficacy of the repair system. As many as 25 patients will be slated for enrollment in the initial phase of the clinical trial, which is to be conducted in four US medical institutions. Dr. Deaton and Takao Ohki, MD, PhD, of Jikei University School of Medicine in Tokyo, were part of a team of specialists who worked during the last 2 years on the device's design and performed the first human implants of the device last summer in Venezuela. Both of those patients had successful outcomes and continue to do well, the hospital noted. Georgetown and its team of vascular surgeons were chosen as the site for the initial US procedure as a result of their involvement in the development of the device in cases done outside the US and during the preclinical phase, the hospital stated.

The current patient is a 69-year-old man who lost both of his parents to AAAs, so he was keenly aware of the danger represented by AAAs. He immediately sought vascular consultation at Georgetown when his primary care physician detected his aneurysm after an ultrasound test. The procedure occurred Wednesday morning, July 19, and the patient went home Thursday afternoon.

According to Aptus Endosystems, the AAA repair system consists of a highly conformable endograft, which is deployed from a low-profile delivery catheter and a unique endovascular stapler for securely attaching the endograft to the artery wall. The use of endovascular staples is designed to replace the need for barbs and/or transrenal stents, while enabling the treatment of short and angulated proximal necks. Georgetown noted that the Aptus endograft is the first endovascular device to be attached to the aortic tissue with individual staples that reproduce the suture fixation used in open surgical repair of AAAs. The capability to deliver the staples separately, and in locations determined by the surgeon, allows for a much smaller delivery device and secures the graft in place in a manner essentially identical to the grafts used in open surgical repair that has proven long-term results.

"The innovations of the Aptus endograft represent a potential revolution in the applicability and durability of endovascular aneurysm repair," commented Dr. Deaton. "This is the first endovascular technology that allows us to repair the aorta using the principles which are the foundation of the very successful open surgical repair that has been the standard over the last 50 years."

Cook's Zenith AAA Endograft Is First EVAR Device Approved in Japan
August 7, 2006—Cook Incorporated (Bloomington, IN) announced that the Zenith Endograft device for the endovascular repair of abdominal aortic aneurysms (AAAs) has been granted Shonin regulatory approval by the Japanese Ministry of Health, Labor, and Welfare. Cook noted that the Zenith endovascular graft system is the first and only device available for endovascular repair of AAAs in Japan. The device will be distributed in Japan by Medico's Hirata, Inc.

According to Cook, the Shonin filing was approved on July 11. The Zenith endograft is approved as a new medical device and that status will be re-examined 3 years after the approval date. Shonin was granted on the basis of the Zenith US pivotal trial results, and on the basis of the limited confirmation trial that was performed in Japan. The device has been successfully used in the US for 7 years and for 9 years in Europe, the company stated.

On July 13, Professor Takao Ohki, MD, PhD, of Jikei University School of Medicine in Tokyo, performed the first post-Shonin Zenith placement. Dr. Ohki, the newly appointed Chief of Vascular Surgery, had joined Jikei the previous week. According to Dr. Ohki, the first patient was a 62-year-old man who had been waiting for an endograft to become available for more than a year. The OR time (skin to skin) was 80 minutes and was performed under local anesthesia. The AAA was successfully treated with the Zenith endograft and the patient was discharged to home on the second day. Dr. Ohki related that after the procedure the patient said, "The procedure was painless and was worth the wait."

Dr. Ohki added, "The first approval of an endograft marks the beginning of a new era in endovascular therapy in Japan." He said that Shonin of the Gore Excluder (Gore & Associates, Flagstaff, AZ) and the Endologix PowerLink (Endologix Inc., Irvine, CA) is expected in late 2006.

Enrollment Completed in Cook's STARZ-TX2 TAA Trial
July 31, 2006—Cook Incorporated (Bloomington, IN) announced that patient enrollment has been completed in the STARZ-TX2 clinical trial (Study of Thoracic Aortic Aneurysm [TAA] Repair with the Zenith TX2 Thoracic TAA Endovascular Graft). The trial studied the safety and efficacy of Cook's Zenith TX2 for the treatment of TAAs by comparing the performance of the device in treatment of aneurysms in the descending thoracic aorta to traditional open surgery. The trial is assessing device performance, as well as patient survival and rupture rates over a 12-month period. The trial date is being prepared for submission to the FDA later this year for device approval, stated the company.

The trial enrolled more than 200 patients at 39 clinical sites around the world. All patients enrolled in the STARZ-TX2 trial are being evaluated at regular intervals during the 12 months after either insertion of the Zenith TX2 or open surgery. Patient data will continue to be monitored regularly. Cook said that while it has now enrolled enough patients to fulfill the study criteria, 11 clinical trial sites in North America are still providing TAA treatment with the Zenith device to patients through continued access. While designated as an investigational device and not commercially available in the US, the Zenith TX2 has been approved for sale in Europe, Australia, Brazil, Thailand, Singapore, Argentina, Peru, Mexico, Columbia, and New Zealand, the company noted.

FDA Approves Study of Abbott Vascular's Xpert Stent for Placement Below the Knee
May 31, 2006—VIVA Physicians, Inc. (VPI, San Jose, CA) and Abbott Vascular, Inc. (a division of Abbott Laboratories, Redwood City, CA) announced that the FDA has cleared the first US, multicenter, prospective clinical trial to investigate the use of minimally invasive stent placement to treat severe peripheral arterial disease (PAD) below the knee. The study, titled XCELL, is sponsored by VPI and supported by a restricted educational grant from Abbott Laboratories. The FDA has approved an investigational device exemption (IDE) for the study for the use of Abbott's Xpert expandable nitinol stent below the knee. VPI submitted its IDE application to study the stent's use in the popliteal and tibial arteries to the FDA on February 7. The Xpert is currently cleared in the US to treat blockages in the biliary ducts.

According to James Joye, DO, Principal Investigator for the XCELL trial, the study is one of only a very few independent, physician-sponsored efforts. VPI set the protocol, applied for the IDE, and is responsible for data collection, evaluation, and reporting. The study is expected to enroll 140 patients at 10 centers. The primary endpoint of the study is avoidance of major amputation at 12-months follow-up after treatment, Dr. Joye said.

"The Xpert stent is particularly appropriate for this trial because it is the only self-expanding stent that comes in a variety of sizes small enough to treat the blood vessels below the knee," commented Dr. Joye, whose center, El Camino Hospital in Mountain View, California, will be a participating site in the study.

Role of Cytokines in AAAs Demonstrated in Study
May 1, 2006—Koici Shimizu, MD, et al from The Donald W. Reynolds Cardiovascular Clinical Research Center at Harvard Medical School published "Inflammation and Cellular Immune Responses in Abdominal Aortic Aneurysms (AAAs)," which considered the role of Th1/Th2 cytokines in vascular disease. The article appeared as part of a series of brief reviews in Arteriosclerosis, Thrombosis, and Vascular Biology (2006;26:987-994) titled "Abdominal Aortic Aneurysms: Pathophysiological Mechanisms and Clinical Implications."

The investigators began with the observation that expansion and rupture of AAAs result in high morbidity and mortality rates. Like stenotic atherosclerotic lesions, AAAs accumulate inflammatory cells, but usually exhibit much more extensive medial damage. Leukocyte recruitment and expression of pro-inflammatory Th1 cytokines typically characterize early atherogenesis of any kind, and modulation of inflammatory mediators mutes atheroma formation in mice. However, the mechanistic differences between stenotic and aneurysmal manifestations of atherosclerosis remain unexplained. The investigators had recently showed that aortic allografts deficient in interferon signaling developed AAAs correlating with skewed Th2 cytokine environments, suggesting important regulatory roles for Th1/Th2 cytokine balance in modulating matrix remodeling and important implications for the pathophysiology of aortic aneurysm and atherosclerosis. Further probing of their distinct aspects of immune and inflammatory responses in vascular diseases should continue to shed new light on the pathophysiologic mechanisms that give rise to aneurysmal versus occlusive manifestations and atherosclerosis.

Cook Marks 100th Zenith Renu AAA Graft Registry Case
May 3, 2006—Cook Incorporated (Bloomington, IN) announced the completion of the 100th case in the US registry of its Zenith Renu Ancillary Graft for the treatment of patients with a migrating aortic endograft. The Zenith Renu is specifically designed for secondary endovascular intervention in patients who had previous endovascular repair of infrarenal abdominal aortic aneurysms (AAAs). The device has been used to successfully treat more than 300 AAA patients in Europe and Australia since 2002 and has been available in the US since September 1, 2005. The company noted that use of the device is a postapproval activity to document device performance data in the clinical setting.

According to the company, the Zenith Renu is available in two configurations: a main body extension and a converter to accommodate differing endograft designs. It is engineered to treat migrations in either Dacron or ePTFE membrane-based aortic endografts. Other device features include an uncovered suprarenal stent with anchoring barbs to provide strong proximal fixation and enhanced graft-to-vessel sealing and the Flexor introducer system. The device is constructed with a lightweight, strong, shrink-resistant woven synthetic polyester graft material and comes preloaded in a kink-resistant, hydrophilic delivery sheath. A trigger-wire system facilitates accurate placement, controlled release, and stabilization of the ancillary endograft during deployment, while the system's Captor hemostatic valve inhibits blood reflux.

Twelve-Month Clinical Data Presented for Lombard's Aorfix Stent Graft
April 12, 2006—Lombard Medical Technologies PLC (Didcot, Oxfordshire, UK) announced that 12-month clinical results on its Aorfix endovascular AAA stent graft were presented at the 28th Charing Cross International Symposium, which was held April 8-11 at Imperial College in London. According to the company, the follow-up data on 24 trial patients demonstrated freedom from all endoleaks, fracture, migration, or kinking. Aorfix has been used in more than 130 patients worldwide. Several of the AAA bifurcated stent grafts have exceeded 24 months of implantation with no device-related adverse clinical outcomes, the company said. The Aorfix is CE Mark approved in the EU and has obtained IDE approval from the FDA in connection with US clinical trials.

FDA Approves Medtronic's AneuRx AAAdvantage
March 27, 2006—Medtronic, Inc. (Minneapolis, MN) announced that it has received FDA approval of the AneuRx AAAdvantage abdominal aortic aneurysm (AAA) stent graft with Xcelerant delivery system. According to the company, the AneuRx AAAdvantage system offers interventionists a low profile for ease of use, a wider range of lengths and diameters, and other enhancements that allow broader patient applicability than previous generation Medtronic devices. Enhancements to the system include potentially broader proximal and distal sealing areas due to longer aortic bodies, longer and larger straight iliac limbs, and flared iliac limbs and extensions. Other features are improved radiopaque markers and contoured stents. The enhancements will provide greater patient applicability, help reduce the complexity of the procedure, and upgrade the durability of the stent graft, the company stated.

SAAAVE Becomes Law, Providing Medicare Coverage for AAA Screening
February 10, 2006—The Society of Vascular Surgery (SVS) announced that the Screening Abdominal Aortic Aneurysm Very Efficiently (SAAAVE) Act became law with President Bush's signing of S.1932, the Deficit Reduction Act of 2005, on February 8. Also known as the Budget Reconciliation Act, the law contains the key SAAAVE provisions that will implement AAA screening as a Medicare benefit. Effective January 1, 2007, SAAAVE will provide for one-time AAA screening as part of the Welcome to Medicare physical for males with any history of smoking and those with a family history of AAAs. The proposed measures for a national education and information campaign and standards sections were not included in the final bill.

The National Aneurysm Alliance (NAA), which includes the SVS, led the campaign to bring the urgent need for widespread AAA screening to the attention of Congress, and with this latest development, vascular health will be positioned at the forefront of public awareness, the SVS stated. The NAA is a coalition of medical professional organizations, foundations, patient advocates, and medical technology manufacturers dedicated to reducing the number of Americans who die each year from ruptured aortic aneurysms and other vascular diseases.

According to the SVS, the enactment of SAAAVE is a great victory for both vascular surgeons and their patients. This is the only new preventive benefit that was included in the budget reconciliation measure and is estimated to cost $200 million over 5 years. Pamela Phillips, the SVS's Director of Health Policy and Government Relations, along with representatives of the NAA, met with congressional conference committee members and staff to persuade them to support the inclusion of SAAAVE in the conference committee version of the bill and encouraged House sponsors to do the same. Congressional members had also received numerous letters from SVS members in support of this legislation. Both of these efforts influenced conference committee members to include SAAAVE in the final version of budget reconciliation.

"The members of the SVS are extremely pleased that Congress and President Bush recognize that AAA screening is an important measure that will save thousands of American lives each year," said vascular surgeon Robert Zwolak, MD, a member of the SVS Board of Directors. "Our members worked diligently on SAAAVE. These vascular surgeons concentrate their practices on the prevention and cure of vascular disease, and they know the effectiveness of screening in saving lives."

Study Reveals Cellular Activity Related to AAA Rupture
January 24, 2006—In a study published in Circulation (2006;113:438-445), Matthew M. Thompson, MD, et al concluded that a localized increase in matrix metalloproteinase-8 and -9 (MMP-8 and -9), mediated by native mesenchymal cells, presents a potential pathway for collagen breakdown and abdominal aortic aneurysm (AAA) rupture. The aim of this study was to investigate the proteolytic and cellular activity of ruptured AAAs, focusing on MMPs and their inhibitors (TIMPs). The investigators began by noting that, although it is known that AAA expansion is characterized by extracellular matrix degradation and widespread inflammation, the processes that characterize AAA rupture are not fully understood.

As detailed in Circulation, anterior aneurysm wall biopsies were taken from 55 nonruptured and 21 ruptured AAAs. A further biopsy from the site of rupture was taken from 12 of the ruptured AAAs. MMP-1, -2, -3, -8, -9, and -13, as well as TIMP-1 and -2, were quantified in each biopsy with enzyme-linked immunosorbent assay (ELISA). A comparison of anterior aneurysm biopsies showed no difference in MMP or TIMP concentrations between nonruptured and ruptured AAAs. In a comparison of ruptured AAA biopsies, MMP-8 and -9 levels were significantly elevated in the 12 rupture site biopsies compared with the 12 paired anterior wall biopsies, whereas other MMPs and TIMPs showed no difference. MMP-8 and -9 expression was mediated by native mesenchymal cells and was independent of the inflammatory infiltrate.

Edwards and Medtronic Settle Endovascular Graft Patent Infringement Lawsuit
January 23, 2006—Edwards Lifesciences Corporation (Irvine, CA) announced that it has entered into an agreement with Medtronic, Inc. (Minneapolis, MN) and Medtronic Vascular, Inc. (Santa Rosa, CA), resolving patent infringement litigation initiated in August 2003 by Edwards and Endogad Research Pty. Ltd. (Sydney, Australia), the company formed by the clinician-inventors of the patents. According to the company, the alleged infringement was of certain patents related to modular or multipart endovascular grafts especially suited for treatment of various types of aneurysms, including abdominal aortic aneurysms (AAAs). In exchange for a cash payment of $37.5 million to Edwards and Endogad, Medtronic has been granted nonexclusive licenses to the patents involved in the litigation, as well as other patents relating to endovascular AAA grafts and delivery systems.

Under the terms of the agreement, Medtronic has also purchased delivery system assets to be used with AAA grafts. Edwards and Endogad remain in litigation with Cook Incorporated (Bloomington, IN), and Gore & Associates (Flagstaff, AZ) regarding infringement of the patents that are owned by Endogad and exclusively licensed to Edwards Lifesciences. The products named in the original suit include Medtronic's AneuRx Stent Graft and Talent Stent Graft Systems, Cook's Zenith Endovascular Graft, and Gore's Excluder Bifurcated Endoprothesis, stated Edwards.

2005

Regression of AAA Linked to Inhibition of JNK Molecules
December 1, 2005—In Nature Medicine (2005;11:1330-1338), Koichi Yoshimura, MD, et al, from Yamaguchi School of Medicine in Japan reported that they have identified c-Jun N-terminal kinase (JNK) as a proximal signaling molecule in the pathogenesis of abdominal aortic aneurysms (AAAs). According to the investigators, human AAA tissue showed a high level of phosphorylated JNK. In the article, the investigators show that JNK programs a gene expression pattern in different cell types that cooperatively enhances the degradation of the extracellular matrix while suppressing biosynthetic enzymes of the extracellular matrix. Selective inhibition of JNK in vivo not only prevented the development of AAA but also caused regression of established AAA in two mouse models. Thus, JNK promotes abnormal extracellular matrix metabolism in the tissue of AAA and may represent a therapeutic target, the investigators stated.

Congress Moves Toward Coverage for AAA Screening
November 3, 2005—The US Senate voted unanimously to support a measure that would provide coverage for ultrasound screening for abdominal aortic aneurysms (AAAs) under part B of the Medicare program. The provision was voted as amendment S.2419 and included as section 6117 to Senate bill S.1932, which is known as the Deficit Reduction Omnibus Reconciliation Act of 2005. Senator Rick Santorum (R-PA) was the primary sponsor of the amendment. The omnibus bill was approved by the Senate, 52-47, and now goes to the House of Representatives for consideration.

The measure, if passed into law, would apply to ultrasound screenings for AAAs performed on or after January 1, 2007. Coverage would be limited to a one-time ultrasound screening by a qualified technologist of any Medicare beneficiary who has had a "Welcome to Medicare" physical and who manifests certain risk factors for cardiovascular disease as determined by the US Preventive Services Task Force (such as evidence of atherosclerosis, hypertension, or a history of smoking). In addition to the AAA screening program, the legislation provides for a national educational and information campaign to be carried out by the Secretary of Health and Human Services in consultation with relevant national medical societies to promote awareness among health care practitioners and the general public with respect to the importance of early detection and treatment of AAAs. The Secretary would be authorized to make appropriate grants of money to national medical, vascular technologist, and sonographer societies for AAA education programs for practitioners and providers.

The current legislation is a modification of a bipartisan initiative originally known as the SAAAVE (Screen Abdominal Aortic Aneurysms Very Efficiently) Act of 2005, which was introduced in the Senate as S.390 and the House of Representatives as H.R.827 earlier this year (Endovascular Today, March 2005). Congressional leaders for the SAAAVE provisions have been Senators Jim Bunning (R-KY) and Christopher Dodd (D-CT), who were cosponsors of the current amendment. In the House, Representatives John Shimkus (R-IL), Gene Green (D-TX), and Ron Lewis (R-KY) introduced SAAAVE. The SAAAVE legislation has been supported by a number of medical professional societies including the Society for Vascular Surgery and the Society of Interventional Radiology, as well as patient advocates, foundations, and medical technology manufacturers.

CardioMEMS Launches Endosure Wireless AAA Pressure Measurement System
November 1, 2005—CardioMEMS, Inc. (Atlanta, GA) announced that the FDA has granted 510(k) clearance for the EndoSure Wireless AAA Pressure Measurement System for measuring intrasac pressure during endovascular abdominal aortic aneurysm (AAA) repair and for use as an adjunctive tool in the detection of intraoperative endoleaks. An immediate US market launch was also announced.

According to the company, the FDA approval is based upon completion of the APEX (Acute Pressure measurement to confirm aneurysm EXclusion) clinical trial. In the study, more than 100 patients in Brazil, Argentina, Canada, and at nine hospitals in the US successfully received an EndoSure sensor at the same time they had a stent graft inserted to repair their aortic aneurysm. Implantation of the EndoSure Wireless AAA Pressure Sensor did not lead to any adverse events in the clinical trial. Last June, Co-Principal Investigator, Takao Ohki, MD, who performed the first implantation of the sensor in a patient, presented preliminary results of the APEX trial at the Society of Vascular Surgery annual meeting in Chicago.

The company stated that the EndoSure Sensor is the first wireless, unpowered, permanently implantable pressure sensor for human use to be commercially available in the US. The system is based on recent innovations in both microelectromechanical systems (MEMS) and wireless technologies. The system comprises the EndoSure Sensor, a unique delivery catheter, the external interrogation device, and proprietary software. The EndoSure Wireless AAA Pressure Sensor is implanted during the endovascular aortic repair procedure and is compatible with all commercially available stent grafts. Accurate pressure measurements within the aneurysm sac can be taken simply and efficiently, the company stated. To take a measurement, the physician places the antenna on the patient's abdomen and activates the sensor using low-power radiofrequency energy. A real-time, high-resolution pressure waveform is quickly displayed on a 15-inch, flat-panel, touch screen monitor.

"The implantation of the EndoSure is straightforward and safe," commented Dr. Ohki. "I believe that over time this important new technology may demonstrate its value by helping physicians confirm that aneurysms have been effectively treated with EVAR procedures and also identify problems that may arise."

CE Mark Granted for Cook's Zenith Endograft for Complex AAAs
October 25, 2005—Cook Incorporated (Bloomington, IN) announced that the Zenith Fenestrated AAA Endovascular Graft has received CE Mark certification, making it commercially available in the EU to treat complex abdominal aortic aneurysms. According to the company, the Zenith's design incorporates tailored openings or scallops called fenestrations in the top section of the endograft, which allow the self-expanding stent graft to treat aortic and aortoiliac aneurysms extending close to the renal and superior mesenteric arteries, which are then stented to reduce the risk of restricting or blocking critical blood flow to the kidneys and bowel. Each fenestrated device is custom-made to suit individual patients' anatomy. The Zenith design features include suprarenal fixation with anchoring barbs to ensure maximal stability and graft-to-vessel sealing, woven polyester graft material that is lightweight, strong, and shrink-resistant, and the H&L-B One-Shot Introducer System that allows simple, accurate deployment and positioning of the graft, the company stated.

"For the first time, we're seeing the possibility of offering safe, effective endovascular treatment for diseases affecting the more proximal aorta," said Roy K. Greenberg, MD, US Principal Investigator. "As branch technology joins the fenestrated family, the entire aorta falls within the domain of aortic interventionists."

Early Outcomes of Endovascular Repair of Ruptured AAAs Examined
October 1, 2005—In the Journal of Vascular and Interventional Radiology (JVIR. 2005;16:1309-1312), Michael Brandt, MD, et al from University Hospital Schleswig-Holstein in Kiel, Germany, published their findings from a retrospective review of 39 consecutive patients treated for ruptured abdominal aortic aneurysms (AAAs) from 2001 to 2004. The investigators examined the impact of the introduction of endovascular treatment on the early outcomes of ruptured AAAs and assessed the suitability of acute endovascular aneurysm repair (EVAR) in patients with ruptured AAAs.

The patients were divided into two groups: 15 who underwent open repair from 2001 to 2002 (group I) and 24 who were treated with open repair (n = 13; 54%) or endovascular repair (n = 11; 46%) from 2003 to 2004 (group II). Hospital charts and computed tomographic scans were reviewed to evaluate the feasibility of EVAR. Age, gender, and aneurysm size were similar between the two groups.

The 30-day mortality rates were 53% in group I and 8% in group II. Median procedure times were shorter in the patients who underwent EVAR. Intensive care unit stay and hospital stay were 22 days and 29.7 days, respectively, in group I, and 5.6 days and 16.1 days, respectively, in group II. Eleven patients were found ineligible for EVAR as a result of an unsuitable neck (n = 5), iliac arteries (n = 3), or both (n = 3). No graft failures were detected during follow-up.
As reported in JVIR, the study found that after introduction of acute EVAR, a total of 46% of patients with ruptured AAAs were treated with the procedure and that, potentially, 54% of patients could have been suitable for EVAR. Dr. Brandt et al concluded that endovascular stent graft implantation has significantly improved outcomes in ruptured AAAs and may therefore be beneficial in the overall treatment strategy in these patients.

Poor Outcomes Shown in Mild Stroke Patients Who Do Not Receive tPA
November 1, 2005—In a retrospective analysis of data from a prospective single-center study, Eric Smith, MD, et al showed that a substantial minority of patients deemed "too good to treat" (TGT) with intravenous tissue plasminogen activator (tPA) were unable to be discharged home (Stroke. 2005;36:2497-2499). The investigators concluded that a re-evaluation of the stroke severity criteria for tPA eligibility may be indicated.

The investigators found that some of these TGT patients with mild or improving ischemic stroke symptoms who do not receive tPA have poor outcomes. The data reviewed were from a study conducted between 2002 and 2004 of 128 patients presenting within 3 hours of stroke onset. Of these patients, 41 (34%) were not given tPA because of mild or improving stroke. Of the TGT patients, 11 of 41 (27%) died or were not discharged home because of neurological worsening (n=6) or persistent "mild" neurological deficit (n=5). No single variable at presentation was associated with death or lack of home discharge. Ten of 41 TGT patients (24%) had four-point improvement in National Institutes of Health Stroke Scale score before tPA decision; these patients were more likely to have subsequent neurological worsening, the investigators stated.

Cook Launches Zenith Renu AAA Ancillary Graft for Secondary Endovascular Intervention
August 18, 2005—The Zenith Renu AAA Ancillary Graft from Cook Incorporated (Bloomington, IN) has received FDA approval and will be available to US physicians in September, the company announced. The device has been available in Europe and Australia since 2002. The Zenith Renu is specifically designed for secondary endovascular intervention in patients who have received prior endovascular repair of infrarenal abdominal aortic aneurysms (AAAs). The Zenith Renu is available in two configuration options: a main body extension and a converter; and, it has been engineered to treat migrations in either Dacron or ePTFE membrane-based aortic endografts, the company says. Utilizing an uncovered suprarenal stent with anchoring barbs, the Zenith Renu provides strong proximal fixation and enhanced graft-to-vessel sealing. The woven synthetic polyester graft material is the same strong, lightweight, and shrink-resistant material that has been used in all of Cook's Zenith endografts. The new Zenith Renu graft system also uses Cook's Flexor Introducer System that features a kink-resistant, hydrophilic delivery sheath. A trigger-wire system facilitates accurate placement, controlled release, and stabilization of the ancillary endograft during deployment, while the system's Captor Hemostatic Valve inhibits blood reflux, the company says.

Endologix to Conduct Powerlink AAA Clinical Trial
July 26, 2005—Endologix, Inc. (Irvine, CA) has received FDA approval to enroll patients in a clinical trial using its Powerlink system to treat abdominal aortic aneurysms (AAAs) in patients with large-diameter aortic necks. According to the company, if it is cleared for marketing in the US, the Powerlink system would be the only endoluminal stent graft (ELG) for use in AAA patients with aneurysm neck diameters up to 32 mm. Endologix estimates that 5% to 10% of AAA patients evaluated for minimally-invasive treatment are excluded due to a large aortic neck diameter. There are currently three FDA-approved ELG devices to treat aortic necks up to 26 mm in diameter and one ELG that is approved to treat necks up to 28 mm in diameter, the company says. Endologix says that the Powerlink system is designed with multiple main body lengths and diameters, as well as 25-mm, 28-mm, and 34-mm cuffs, and multiple limb extensions, to improve its adaptability to variations in patient anatomies.

The company also announced that the FDA has allowed inclusion of a large-diameter Powerlink ELG in the ongoing suprarenal arm of its clinical study, which the company says should accelerate enrollment and permit physicians to treat patients who cannot be treated with an FDA-approved ELG. Endologix also received approval to initiate a seven-center, 60-patient protocol using a large-diameter infrarenal cuff with its approved Powerlink bifurcated device. These two studies will permit Endologix to study alternative implant strategies to treat this subset of patients, the company says. Endologix expects to begin enrollment in both studies in the third quarter of 2005.

PIVOTAL Trial Will Study Early EVAR for Small AAAs
July 7, 2005—The Cleveland Clinic and Medtronic, Inc. (Santa Rosa, CA) separately announced commencement of the largest US clinical trial to determine if early endovascular aneurysm repair (EVAR) after diagnosis of small abdominal aortic aneurysms (AAAs) is preferable to waiting and monitoring the growth of the aneurysm before intervening.

PIVOTAL (Positive Impact of EndoVascular Options for Treating Aneurysms Early) is a multicenter, prospective, randomized trial comparing early stent graft intervention to medical surveillance. PIVOTAL will be conducted at 70 centers in the US and will enroll approximately 1,680 patients. Half of the patients diagnosed with aneurysms between 4 cm and 5 cm will be randomized to immediate EVAR using Medtronic's AneuRx abdominal aortic stent graft system. The other half will be monitored with ultrasound every 6 months. Those in the surveillance group who develop symptoms or experience enlargement can be treated with either an open or endovascular repair procedure. The two groups will be observed for 5 years to track differences in outcomes as they relate to any aneurysm or aneurysm repair.

PIVOTAL's primary endpoint is the cumulative occurrence of the composite of rupture or aneurysm-related death within 3 years. Secondary endpoints include all-cause mortality and aneurysm-related mortality in smokers versus nonsmokers, aneurysm rupture, duration of hospital stay, procedure duration, and many other endpoints related to the use of the stent graft.

"The advent of a minimally-invasive approach with stent grafts may offer an option that is reasonable for smaller aneurysms," said Kenneth Ouriel, MD, of the Cleveland Clinic and Principal Investigator of the trial. "This contention, however, must be proven with a clinical study."

UK, Dutch Trials Show Short-Term EVAR Advantages Are Not Sustained
June 23, 2005—Four-year follow-up results from two related British trials comparing the safety, efficacy, and durability of endovascular aneurysm repair (EVAR) versus open surgery and nonintervention for the treatment of abdominal aortic aneurysms (AAAs) have been published by Professor Roger M. Greenhalgh, MD, and colleagues in The Lancet (2005;365:2179-2192). The multicenter, randomized, controlled trials for patients fit for open repair (EVAR-1) and for high-risk patients considered unfit for major surgery (EVAR-2) comprised 1,420 patients at 42 hospitals in the UK under the direction of Professor Greenhalgh at London's Charing Cross Hospital.

Last year, EVAR-1 showed in 30-day follow-up results that endovascular repair was demonstrably better for the treatment of AAAs than open surgical procedures, but now those initial overall advantages are shown to be unsustained over time. Conversely, the difference in aneurysm-related death favors endovascular repair, with the EVAR-1 trial demonstrating that the operative mortality benefit of 3% at 30 days is maintained at 4 years.

In EVAR-1, the researchers compared EVAR to open surgery in terms of mortality, durability, health-related quality of life (HRQL), and costs for patients with large AAAs. The primary endpoint was all-cause mortality, with secondary endpoints of aneurysm-related mortality, HRQL, postoperative complications, and hospital costs.
The study found that four years after randomization, all-cause mortality was similar in the two groups (about 28%), although there was a persistent reduction in aneurysm-related deaths in the EVAR group (4% vs 7%). The proportion of patients with postoperative complications within 4 years of randomization was 41% in the EVAR group and 9% in the open repair group. After 12 months, a negligible difference in HRQL existed between the two groups. The mean hospital cost per patient up to 4 years was £13,257 for the EVAR group versus £9,946 for the open repair group.

The researchers concluded that, compared with open repair, EVAR offers no advantage with respect to all-cause mortality and HRQL, is more expensive, and leads to a greater number of complications and reinterventions. However, it does result in a 3% better aneurysm-related survival. The continuing need for interventions mandates ongoing surveillance and longer follow-up of EVAR for detailed cost-effectiveness assessment, according to the authors.

In the EVAR-2 trial, as reported in The Lancet, endovascular treatment to exclude AAAs was introduced for patients of poor health status considered unfit for major surgery. EVAR-2 sought to identify whether EVAR improves survival compared with no intervention in patients unfit for open repair of AAAs. The primary endpoint was all-cause mortality, with secondary endpoints of aneurysm-related mortality, HRQL, postoperative complications, and hospital costs. Analyses were by intention to treat.

Professor Greenhalgh and colleagues reported that 197 patients underwent aneurysm repair (versus 47 who were assigned to no intervention) and 80% of patients adhered to protocol. The 30-day operative mortality in the EVAR group was 9% and the no-intervention group had a rupture rate of nine per 100 person years. By the end of follow-up, 142 patients had died, 42 of aneurysm-related factors; overall mortality after 4 years was 64%. There was no significant difference between the EVAR group and the no-intervention group for all-cause mortality. There was also no difference in aneurysm-related mortality. The mean hospital costs per patient over 4 years were £13,632 in the EVAR group and £4,983 in the no-intervention group, with no difference in HRQL scores.

The authors' interpretation of the findings was that EVAR had a considerable 30-day operative mortality in patients already unfit for open repair. EVAR did not improve survival over no-intervention and was associated with a need for continued surveillance and reinterventions, at substantially increased cost. Finally, they concluded that ongoing follow-up and improved fitness of these patients is a priority.
"The EVAR trial results will affect clinical practice at once. There will be cautious enthusiasm for the use of EVAR in low-risk patients, but personally I shall not offer EVAR in high-risk patients," Professor Greenhalgh said. "An important minority of patients are anatomically unsuited for EVAR in our current state of knowledge, and surgeons must still be trained to do open aneurysm repair. Vascular specialists of the future will need operative and catheter skills to be able to manage all problems."
In The New England Journal of Medicine (2005;352:2398-2405), Jan D. Blankensteijn, MD, and colleagues for the Dutch Randomized Endovascular Aneurysm Management (DREAM) Trial Group, reported that 2-year outcomes after conventional open repair versus endovascular repair of AAAs showed no significant differences in overall survival, although there was a difference in aneurysm-related death in favor of endovascular repair.

As in the British EVAR-1 trial, the smaller DREAM study of 351 patients reported last year that 30-day outcomes were demonstrably better for elective endovascular treatment of AAAs than for conventional open repair. Now, however, the DREAM group reports that at 2 years after randomization, the perioperative survival advantage with endovascular repair compared to open repair is not sustained after the first postoperative year. The cumulative survival rates were 89.6% for open repair and 89.7% for endovascular repair. The cumulative rates of aneurysm-related death were 5.7% for open repair and 2.1% for endovascular repair (P=.05). As reported in the NEJM, this advantage of endovascular repair was entirely accounted for by events occurring in the perioperative period, with no significant difference in subsequent aneurysm-related mortality. The rate of survival, without moderate or severe complications, was also similar in the two groups at 2 years (65.9% for open repair and 65.6% for endovascular repair). The multicenter, randomized trial studied 351 patients diagnosed with AAA with diameters of 5 cm or greater who were considered suitable candidates for both techniques.

"The results of the DREAM trial at 2 years indicate that endovascular repair is still advantageous over open repair when aneurysm-related death is considered." said DREAM coauthor Hence J.M. Verhagen, MD, PhD, vascular surgeon at the University Medical Center, Utrecht, The Netherlands. "In terms of overall survival, however, this difference seems to be cancelled out by excess mortality from other causes, mainly cardiovascular, in the endovascular-treated group."

Dr. Verhagen added, "Whether this new finding will affect the choice of treatment remains to be seen and will probably rely much more on results after a longer follow-up period, but those will not be available for some time. At present, the choice of the preferred treatment will still be made after careful consideration of the pros and cons of the two treatment modalities for every individual patient. The 2-year DREAM results may, however, influence the personal preference of the patient, family, or surgical team."

Vascutek Launches Anaconda AAA Stent Graft in Europe
April 5, 2005—Vascutek, a Terumo company, (Glasgow, Scotland, UK) announced the European introduction of the Anaconda AAA stent graft system. According to the company, the system has been CE marked based on the results from a clinical trial begun in June 2002, with patient follow-up out to 24 months and a mean follow-up of 13.5 months. The company described the Anaconda as an intuitive and modular design, which is repositionable and flexible. Anaconda is close to concluding a phase 1 IDE study in the US, the company says

Bolton Medical's Relay Thoracic Stent Graft Receives CE Mark
April 8, 2005—Bolton Medical (Sunrise, FL) has received CE Mark approval for its Relay Thoracic Stent Graft and Transport Delivery System. The Relay, according to the company, is designed to be able to treat the specific challenges associated with lesions in the thoracic aorta, particularly in the arch area. Reaching the site of the lesion is achieved by the Transport Delivery System, which the company says is designed to navigate through the femoral and iliac entry sites but still be flexible enough to accommodate any severe angles and tortuosity associated with the thoracic arch. The Relay is currently being tested in clinical trials in the US.

Medtronic Xcelerant Used With Talent AUI Introduced in Europe
April 8, 2005—Medtronic, Inc. (Santa Rosa, CA) has announced the market availability of the Xcelerant Delivery System for use with the Talent Aorto Uni-Iliac (AUI) Stent Graft System. The Talent AUI Stent Graft System is approved for use outside the US for the treatment of abdominal aortic aneurysms (AAAs), according to the company. The Talent AUI system with the CoilTrac delivery system has been available outside the US since 1999. The Xcelerant Delivery System, the company says, features an improved catheter material and integrated deployment handle to enhance trackability, improve kink resistance, and decrease deployment force.

Hence J. M. Verhagen, MD, and colleagues at University Hospital, Utrecht, The Netherlands, successfully performed the first worldwide implant of the Talent AUI Stent Graft using the Xcelerant Delivery System. They performed the implant on a patient with extremely tortuous iliac arteries, and the system performed as expected, the company says.

"The trackability of the Xcelerant Delivery System is phenomenal, and this is particularly important when you are dealing with challenging anatomies," said Dr. Verhagen. "The delivery is smooth, easy, and very precise."

Depending on anatomical and other considerations, AUI systems can be used in place of AAA bifurcated systems. These considerations may include large bilateral common iliac artery aneurysms, iliac arteries that are not uniform in size, extremely tortuous or highly diseased iliac arteries, or tight distal aortic necks in which bifurcated AAA devices are not feasible. The Talent AUI system comes in a variety of combinations and configurations that allow the physician to tailor the device to the individual patient. The two-piece AUI design has interchangeable proximal and distal components to allow quick, convenient treatment of a broad range of anatomical diameters and lengths.

Gore TAG Thoracic Endoprosthesis Receives FDA Marketing Approval
March 24, 2005-The FDA has granted W.L. Gore & Associates Inc. (Flagstaff, AZ) approval to market the Gore TAG Thoracic Endoprosthesis, the first device of its kind approved in the US for treatment of patients with aneurysms in the descending thoracic aorta. The company says that observed rates from the Gore TAG Device Pivotal Study demonstrated the Gore TAG Device group had lower operative paraplegia/paraparesis (3% vs 14%), lower operative mortality (1% vs 6%) and significantly less average procedural blood loss (472 mL vs 2,402 mL) as compared to the open surgical control group. The Gore TAG Device group experienced a 66% reduction in aneurysm-related death and had no aneurysm ruptures through 2 years. Furthermore, the company notes, patients who received the Gore TAG Device were able to return to normal activity in less time than those undergoing open surgery (30 days vs 78 days).

Michael D. Dake, MD, performed the first post-FDA approval procedure using the Gore TAG Endoprosthesis at the University of Virginia Health System Hospital (Charlottesville, VA), where Dr. Dake is Chair of Radiology. "Today marks the beginning of a new era of less-invasive repair of thoracic aortic aneurysms, which will provide a safer alternative to traditional surgery in some patients," Dr. Dake said. "Ultimately, the use of this technology may be expanded to manage a variety of challenging aortic diseases with less risk and offers new hope for improved results over current treatment of patients."

CE Mark for Medtronic's Valiant Thoracic Stent Graft
March 21, 2005—Medtronic, Inc. (Santa Rosa, CA) has announced CE Mark approval for the Valiant Thoracic Stent Graft with Xcelerant Delivery System as of March 2005. Medtronic conducted preclinical studies with endovascular pioneers Rodney White, MD, vascular surgeon at Harbor-UCLA Medical Center (Torrance, CA), and Mark Farber MD, vascular surgeon at the University of North Carolina at Chapel Hill (Chapel Hill, NC).

Dr. White commented, "The Valiant System is based on the Talent platform, which has a long history of proven results. With the changes Medtronic has made, the preclinical testing demonstrated excellent conformability and deliverability, essential benefits physicians need to confidently treat challenging thoracic anatomy. It will be interesting to compare the results of the first clinical implants that are planned to occur in Europe later this spring." Dr. Farber added, "The new Valiant graft is promising in that it addresses a number of thoracic treatment challenges that currently have no solution. A choice of fixation options, the largest diameters and multiple lengths are especially important for applicability in various disease states. The Xcelerant delivery system is similar to the one already being used on the AneuRx and Talent AAA devices."

Medtronic is planning for a US clinical trial of the Valiant Thoracic Stent Graft with Xcelerant Delivery System to occur in the next 12 months.

2004

Bolton to Commence Phase I TAA Trial
December 8, 2004—Bolton Medical (Sunrise, FL) was authorized by the FDA to commence a Phase I clinical trial of its Relay TAA Stent Graft to evaluate the device's preliminary safety and performance. The study will encompass 30 patients at five investigational sites. The focus of the clinical trial will be the endovascular treatment of various forms of thoracic aortic aneurysms. An expanded Phase II trial is planned.

According to the company, the Relay TAA Stent Graft was designed to accommodate the specific challenges of the thoracic aortic arch. The Relay is delivered endovascularly to the target site using the Transport delivery system, which is designed to be able to navigate through the tortuous small femoral and iliac entry sites, but still be flexible enough to accommodate the severe angles associated with the thoracic arch.

FDA Approves Endologix Powerlink System
November 1, 2004—Endologix, Inc. (Irvine, CA) has received FDA approval for commercial distribution of the Powerlink System, an endoluminal stent graft for the treatment of abdominal aortic aneurysms (AAAs). The Powerlink System features a one-piece, bifurcated design, with a one-piece, cobalt-chromium alloy cage, single-wire main body construction, and a minimally invasive delivery mechanism. The standard FDA conditions for approval apply: continued postmarketing surveillance and annual update reports to the FDA and physician-users.

FDA approval of the Powerlink System centered on the results of the Endologix pivotal clinical trial of 192 test patients and 66 controls treated by conventional open surgery. The Powerlink System was successfully deployed in 97.9% of test patients. Thirty-day postoperative mortality rates for the Powerlink System were 1.04% versus 6.06% for surgery. Mean length of hospital stay was 3.3 days versus 9.5 days in the control group. The trial also demonstrated significantly lower operative time, blood loss, and ICU stay for the Powerlink System patients versus the surgical patients. Thirty-three percent of Powerlink patients were treated with a regional or local anesthesia.
The Powerlink results included negligible device migration, low endoleak rate, and no reported AAA ruptures, wire form fractures, or material failures of the device. At 24 months, core lab analysis showed that in 98.6% of patients the maximum diameter of the aneurysm sac decreased (63.9%) or remained stable (34.7%).

Cook Launches AAA Practice Builder Kit
November 19, 2004—Cook Incorporated (Bloomington, IN) introduced the Abdominal Aortic Aneurysm (AAA) Physician Practice Builder Kit at the 2004 VEITHsymposium in New York City. The kit is designed to provide a comprehensive set of tools and information for health care professionals to communicate to patients the nature and treatment options of AAA and to enhance understanding of AAA among physicians' referral networks. Among the kit's features are templates for physician-to-physician introductory and follow-up letters, AAA screening instructional sheets, patient education brochures, and a patient video.

FDA Approves Endologix Powerlink System
November 1, 2004—Endologix, Inc. (Irvine, CA) has received FDA approval for commercial distribution of the Powerlink System, an endoluminal stent graft for the treatment of abdominal aortic aneurysms (AAAs). The Powerlink System features a one-piece, bifurcated design, with a one-piece cobalt-chromium alloy cage, single-wire main body construction, and a minimally invasive delivery mechanism. The standard FDA conditions for approval apply: continued postmarketing surveillance and annual update reports to the FDA and physician-users.

FDA approval of the Powerlink System centered on the results of the Endologix pivotal clinical trial of 192 test patients and 66 controls treated by conventional open surgery. The Powerlink System was successfully deployed in 97.9% of test patients. Thirty-day postoperative mortality rates for the Powerlink System were 1.04% versus 6.06% for surgery. Mean length of hospital stay was 3.3 days versus 9.5 days in the control group. The trial also demonstrated significantly lower operative time, blood loss, and ICU stay for the Powerlink System patients versus the surgical patients. Thirty-three percent of Powerlink patients were treated with a regional or local anesthesia.

The Powerlink results included negligible device migration, low endoleak rate, and no reported AAA ruptures, wire form fractures, or material failures of the device. At 24 months, core lab analysis showed that in 98.6% of patients the maximum diameter of the aneurysm sac decreased (63.9%) or remained stable (34.7%).

EVA To Begin AAA Endostaple Human Testing
October 21, 2004—EndoVascular Associates Incorporated (EVA, Bethesda, MD) has received FDA approval to undertake initial human testing of the company's endovascular AAA Endostaple repair device. The Endostaple is intended to work as an enabling technology to prevent or correct endoleak issues associated with currently available devices for endovascular aneurysm repair. Human testing is expected to begin in the first quarter of 2005 at three US centers.

EVA also announced that the National Institutes of Health has issued a Phase I grant that will allow the company to begin work on work on a second-stage device that would combine EVA's Endostaple with an unsupported, or nonstented, graft.

Cook to Launch New AAA Graft System Q4 2004
October 4, 2004—Cook Incorporated, Inc. (Bloomington, IN), has announced that the next generation of its AAA platform, which includes the Zenith Flex AAA endograft system and the H&L-B One Shot delivery system, has received FDA approval. The system will be available for shipment in the fourth quarter of this year. At this year's TCT meeting, Barry Thomas, Global Leader of Cook's Endovascular Therapies Group, met with Endovascular Today to discuss the new features of the system and Cook's plans regarding its AAA products and programs. Mr. Thomas described the Zenith Flex as having more widely spaced stent bodies to allow the device to better conform to tortuous anatomy. The H&L-B One Shot Delivery System features a double-valve system--the Captor Hemostatic Valve--to inhibit blood reflux and air aspiration, and Mr. Thomas described the system's Flexor introducer as having a sheath construction that combines flexibility with resistance to kinking or compression. The improvements in graft design and introduction have also been applied to Cook's TX2 thoracic device and to fenestrated versions of each system, which are currently being evaluated in clinical trials.

Cook will soon initiate a practice builder program designed to help AAA specialists develop and maintain a communicative network with general practitioners in their regions. The company will also be unveiling a screening program that will include lobbying Congress to encourage reimbursement for AAA screenings; the program will promote AAA awareness and diagnosis by conducting free regional screenings in a number of US communities.

Gore Introduces New Excluder AAA System
October 4, 2004—W.L. Gore & Associates, Inc. (Flagstaff, AZ), has announced the availability of its low permeability Excluder Endoprosthesis--the latest generation of its Excluder product line. The company reports that the new Excluder employs a microstructure technology that results in significantly reduced permeability during AAA treatment. The device is composed of a durable, ePTFE graft; a low-permeability film layer; ePTFE reinforcing film; an electropolished nitinol stent; and bonding film for stent-to-graft attachment.

FDA Endovascular Graft Testing Workshop
July 13, 2004—The FDA will hold its second Workshop on Preclinical Testing for Endovascular Grafts July 28 to July 29 in Gaithersburg, Maryland. Representatives from various areas involved with the development, testing, and use of endovascular grafts have been invited. There will be four sessions during the workshop: (1) animal studies; (2) fixation effectiveness and sealing; (3) implant integrity; and (4) past, present, and future issues in preclinical testing. Each session will begin with short presentations, which will be followed by discussion from the participants and audience members. For more information, please visit http://www.evtoday.com/Pages/News.html, where you will also find a questionnaire for clinicians regarding endovascular graft experience.

Cook Set to Begin Fenestrated AAA Device Trial
July 15, 2004—Cook Incorporated (Bloomington, IN) has received FDA approval to begin investigational use of a fenestrated version of its Zenith endovascular graft for complex AAAs. The company reports that the fenestrated devices are highly customized to meet the anatomic needs of each patient. Scallops at the top and fenestrations in the walls of the graft allow it to be implanted precisely in the aorta across adjacent vessels without blocking blood flow through those vessels.

The FDA approved Cook's Investigational Device Exemption application for clinical studies at five US medical institutions involving 25 patients. The Zenith fenestrated graft is approved for sale in Australia and is available as a custom device in Europe.

Medtronic Launches New AneuRx Graft Material; Receives CE Mark for Xcelerant Delivery System
July 14, 2004—Medtronic, Inc. (Santa Rosa, CA), has announced the availability of its new Resilient graft material for its AneuRx AAA Stent Graft System. The company comments that the Resilient material provides the device with higher density graft material designed to reduce porosity and improve durability. The enhanced AneuRx marks the fourth generation of the device.

"I have always been a big fan of the AneuRx stent graft due to its proven durability and versatility," stated Takao Ohki, MD, Chief of Vascular Surgery at Montefiore Medical Center in New York. "I also believe that the new material, which is 52% more dense, on average, will only improve the long-term durability and outcome."

Medtronic has also received CE Mark approval for its Xcelerant Delivery System, which is designed for use with the company's Talent AAA system. The Talent system is available for sale outside the US. The company comments that the Xcelerant Delivery System features an improved catheter material and integrated deployment handle to enhance trackability, improve kink resistance, and dramatically decrease deployment forces.

First Vascutek Anaconda Grafts Implanted in US
July 9, 2004—Vascutek (a Terumo company) has announced the commencement of its phase I FDA study for the Anaconda Endovascular Device. The Anaconda has been developed for the treatment of infrarenal aortic aneurysms and is a modular system constructed of polyester graft material and self-expanding nitinol ring-stents. The company comments that it features a fully repositionable, woven polyester body, which is sealed in the infrarenal neck by two flexible, conformable nitinol ring-stents, and is anchored in position by four pairs of nitinol hooks. The two separately deployed legs are supported by individual, flexible, kink-resistant nitinol ring-stents.

The first patient was successfully treated at the Cleveland Clinic by Roy K. Greenberg, MD; two further successful cases were also carried out at the same institution. "The Anaconda device may offer advantages over other commercially available devices currently on the market; among them is proximal stent reconstrainability and the potential to angle the proximal stent within a somewhat tortuous neck," said Dr. Greenberg. "These may allow for the treatment of patients with more complex proximal neck anatomy."

The other three phase I centers and participating physicians are the University of Pennsylvania, where Ronald Fairman, MD, and Jeffrey Carpenter, MD, serve as the trial's national principal investigators, the University of Southern Illinois (Kim Hodgson, MD), and Georgetown University (David Deaton, MD). "We are excited about the Anaconda device clinical trial," commented Drs. Fairman and Carpenter. "With its ability to be repositioned and canted within the aortic neck, it addresses a number of the remaining challenges of infrarenal endografting."

"Vascutek is delighted to begin our clinical program in the US," said Stuart Rodger, Vice President, Clinical Affairs. "Furthermore, we are close to completing enrollment of patients in the European Anaconda Study. We have followed a cautious and prudent path with the Anaconda. We will analyze the data from our European study, and we will not apply the CE mark until the clinical evidence supports that decision."

Two-Year Zenith AAA Data Announced
June 7, 2004—Cook Incorporated (Bloomington, IN) has released the 2-year US clinical trial data for its Zenith AAA endovascular graft. The trial included 352 patients treated at 15 centers. According to the company, among the results are a 97.7% survival rate; 0% stent migration (≥10 mm) in both standard and high-risk patients; 7.5% rate of endoleak (any type), with a 6.9% rate in standard patients; and the diameter of aneurysms remained unchanged or decreased in 97.4% of all patients and in 100% of patients without endoleaks or systemic infection.

Cook Introduces Next-Generation Zenith Flex; Coda Balloon Catheter
June 3, 2004—At this year's annual meeting of the Society for Vascular Surgery in Anaheim, held June 3-6, Cook Incorporated (Bloomington, IN) unveiled its next-generation Zenith Flex AAA Endovascular Graft. Before launching the new Zenith Flex endograft, Cook is waiting for FDA clearance on a new delivery system designed to take full advantage of the new endograft's advanced features. FDA clearance of the delivery system is expected soon.

Cook also recently launched its Coda Balloon Catheter for temporary occlusion of large vessels and the expansion of vascular prostheses. The catheter has a 10-F shaft size that provides stability and allows for a large inflation lumen.