Final Results Published From Pivotal Trial of Medtronic's Endurant AAA Stent Graft System

July 7, 2016—The final 5-year results of the United States pivotal trial for the Endurant abdominal aortic aneurysm (AAA) bifurcated stent graft system (Medtronic) were published by Michael J. Singh, MD, et al in the Journal of Vascular Surgery (JVS. 2016;64:55–62). 

In June 2015, Dr. Singh presented the data from the investigational device exemption study at the Society for Vascular Surgery’s Vascular Annual Meeting. The device received US Food and Drug Administration approval in December 2010.

As summarized in the JVS publication, the prospective multicenter regulatory trial was performed at 26 sites in the United States. In the trial, 150 patients were enrolled and treated with the Endurant device. The main inclusion criteria included AAA diameter > 5 cm (or 4–5 cm in diameter where the size increased > 5 mm within the previous 6 months), neck length ≥ 10 mm, and neck angulation ≤ 60º. 

For regulatory purposes, outcomes from the trial were compared with those from a study of Medtronic’s Talent enhanced low-profile system (eLPS), which had similar inclusion criteria. At 5 years, clinical follow-up was available on 94% of 101 eligible patients, with imaging available on 87%.

The investigators reported that the all-cause mortality rate by Kaplan-Meier estimate was 17.7%, and the rate of freedom from aneurysm-related mortality was 99.2%. One aneurysm-related mortality was noted in a patient that refused treatment for a type I endoleak and died in year 4 from rupture. There were no endograft migrations, fractures, or open conversions reported. 

At 5 years, endoleaks were identified in 7 of 83 patients (8.4%) and included six type II endoleaks and one of indeterminate origin. In 83 patients, the maximum AAA diameter decreased by > 5 mm in 53 patients (63.9%), remained stable in 25 patients (30.1%), and increased > 5 mm in five patients (6%). Eighteen AAA-related secondary interventions were required in 15 patients (11%): 12 for endoleak management, four for limb occlusions, one for stenosis, and one for thromboembolism. Four of five limb occlusions reported were observed in the first 6 months. 

These results led the investigators to conclude that the 5-year outcomes of the Endurant AAA stent graft system as observed in its United States regulatory trial continue to be positive and that the device appears to be durable with limited adverse events through 5 years. Additionally, they advised that comparison with a previous generation device suggests improving outcomes with newer iterations.