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 prox imal abdominal aortic aneurysm endograft fixation from a single device seri es with perpendicular neck measurements in two groups of patients with comp lete 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 ambu latory patients. Subjects: From January 1994 until May 1998, 37 endografts were implanted fo r abdominal aortic aneurysm. In the first postoperative year, there were fo ur 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 wo rk station to measure the neck per pendicular to the central lumen line of the aorta. The surface area at the proximal endovascular anastomosis was re corded 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 3 6 months (c(2) = 27; P < .001, Friedman). This increase in neck size was co ntinuous 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 pr actice 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.