Long-term safety and effectiveness of the TREO stent graft for the endovascular treatment of infrarenal abdominal aortic aneurysms

Objective: The aim of this study is to report on the long-term safety and effectiveness of the TREO stent graft in endovascular repair of abdominal aortic aneurysms from a U.S. investigational device clinical study. Methods: Data from a multicenter, nonrandomized, prospective, U.S. investigational device exemption pivotal study (NCT02009644) were used. From November 2013 to February 2016, a total of 150 patients were enrolled at 29 U.S. centers. Safety end points were defined as major adverse events (ie, all-cause mortality, myocardial infarction, stroke, renal failure requiring renal replacement therapy, respiratory failure, paraplegia, bowel ischemia, and procedural blood loss of 1000 cc or greater). Effectiveness end points were defined as no aneurysm rupture, absence of sac increase >5 mm, absence of migration, patency without reintervention, absence of type I and/or type III endoleaks, and absence of conversion to open surgical repair. The long-term safety and effectiveness of the TREO Stent-Graft System was assessed, with Core Laboratory assessment of the imaging studies and an independent adjudication of safety. Results: The average age of subjects in the pivotal study was 71.7 ± 7.4 years (range: 52-85 years), and 88.0% (132 of 150) of the subjects were men. At 5 years, 90.2% (83 of 92) of eligible subjects had follow-up. Over the course of the study, through 5-year follow-up, 42 (28%) were either lost to follow-up or had an early withdrawal. Twenty-five (19.0%) subjects expired. No deaths were adjudicated as aneurysm-related mortality. Kaplan-Meier estimates of the major adverse event rates were 0.7% at 30 days, 5.4% at 12 months, 11.0% at 2 years, 16.2% at 3 years, 19.3% at 4 years, and 25.4% at 5 years in subjects. Over 5-year follow-up, there were no ruptures or conversions to open surgical repair. Core Laboratory reported the following observations through 5 years: one (0.67%) subject with migration, four (2.7%) subjects with a new type Ia endoleak, one (0.67%) subject with a new type Ib endoleak, no subjects with type III endoleaks, and five (3.45%) subjects with patency-related events that required an intervention. Sac regression was observed in 63 (46.3%) subjects at 1-year, 63 (54.3%) at 2-year, 57 (55.9%) at 3-year, 47 (56.6%) at 4-year, and 43 (61.4%) at 5-year follow-up. Sac expansion was not observed at the 1- or 2-year follow-up; it was first reported at 3 years (5 subjects, 4.9%); four (4.8%) subjects had sac expansion reported at 4 years and two (2.9%) subjects at 5 years. Conclusions: Long-term follow-up for the TREO Stent-Graft System demonstrated durable performance, with low rates of long-term morbidity and mortality, and high rates of long-term sac shrinkage, confirming sustained long-term safety and effectiveness in the repair of infrarenal abdominal aortic aneurysms.