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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.