Concerns for the durability of the proximal abdominal aortic aneurysm endograft fixation from a 2-year and 3-year longitudinal computed tomography angiography study

Objective: To provide a long-term perspective on the durability of the proximal abdominal aortic aneurysm endograft fixation from a single device series with perpendicular neck measurements in two groups of patients with complete 2- and 3-year follow-up. Design: This was a prospective study of postoperative, radiologic images. Setting: The study used a referral center, institutional practice, and ambulatory patients. Subjects: From January 1994 until May 1998, 37 endografts were implanted for abdominal aortic aneurysm. In the first postoperative year, there were four unrelated deaths and six conversions, leaving 27 patients with complete 24-month data and 13 with complete 36-month data. Main Outcome Measure: Computed tomography angiograms were processed on a work station to measure the neck per pendicular to the central lumen line of the aorta. The surface area at the proximal endovascular anastomosis was recorded at each follow-up interval and related to the postoperative size at the same level. Results: Significant dilatation of the surface area was found: 20% (16% to 27%) at 24 months (c(2) = 30; P < .001, Friedman) and 23% (18% to 28%) at 36 months (c(2) = 27; P < .001, Friedman). This increase in neck size was continuous and linear, with a yearly rate of approximately 10% surface area; translated into diameter, this approximates 1 mm/y. Conclusion: A continuous aortic enlargement of approximately 1 mm/y at the level of the proximal endovascular anastomosis was found. Because of the practice of oversizing the endograft relative to the infrarenal aortic neck, a loss of the endovascular seal may not become apparent until several years after endovascular abdominal aortic aneurysm repair is performed.