One year outcomes of the United States regulatory trial of the Endurant Stent Graft System.

Objective: To report the 1-year outcomes of the United States (US) regulatory trial of the Endurant Stent Graft System (Medtronic Vascular), a new device for the treatment of abdominal aortic aneurysms (AAA).

Methods: This was a prospective, single arm, multicenter trial conducted at 26 sites in the US. From April 2008 to May 2009, 150 patients with AAA were treated with the Endurant bifurcated stent graft. The main inclusion criteria were an AAA diameter >5 cm, proximal neck length ≥ 10 mm, bilateral iliac fixation length ≥ 15 mm, and a neck angulation of ≤ 60 degrees. A clinical events committee (CEC) adjudicated all adverse events except blood loss, and a core laboratory reviewed all imaging. The primary safety endpoint was freedom from major adverse events at 30 days, and the primary effectiveness endpoint was successful aneurysm treatment at 12 months.

Results: One hundred forty-nine patients (99.3%) had a successful stent graft implant, 83.3% under general anesthesia. One failure was due to inability to cannulate the contralateral gate. One patient developed a neck rupture during the procedure, but was still treated successfully. Patients were predominantly male (91.3%), elderly (mean age, 73.1 years) with significant comorbidities. Mean estimated blood loss was 185 mL (range, 0-1450 mL), with blood transfusion required in one patient. Average hospital stay was 2.1 days. At 1 month, the major adverse events rate was only 4% with no operative mortality. Serious adverse events were recorded in 43 of 150 (28.7%) patients. Cardiac (8.7%), fever (6%), urological (4.7%), pulmonary (4%), and vascular events (4%) were the most frequent. Through 12 months of follow up, there were no migrations, ruptures, or conversions. No type I or III endoleaks were identified during the first year. Fifteen of 129 patients (11.6%) had endoleaks at 6 months and 13 of 130 (10%) at 1 year, all type II except for one indeterminate endoleak. One Type II endoleak proved to be a Type IB on later angiography. Ten aneurysm related reinterventions were performed during the first year of follow up, mostly for limb thrombosis or stenosis (5) or for type II endoleak (2). Four of the procedures were endovascular. Aneurysm sac diameter decreased >5 mm at 1 year in 47% of patients and remained stable in 53%. No sac showed an increase of >5 mm. None of seven late deaths (range, 90-458 days post-implant) was adjudicated to be aneurysm related.

Conclusion: Early results of the Endurant pivotal trial are quite encouraging and suggest a safe and effective new device for the treatment of abdominal aortic aneurysms.