Factors Affecting Anatomical Changes after Endovascular Abdominal Aortic Aneurysm Repair

Background The primary goal of endovascular aneurysm repair (EVAR) is to prevent death from aneurysm rupture. Regression of aortic sac size is believed to be a marker for success after EVAR. This study analyzes the changes in aneurysm sac size and the factors affecting sac regression after EVAR. Patients and Methods We retrospectively reviewed 121 patients with abdominal aortic aneurysm (AAA) who underwent elective treatment with EVAR at our institution from January 2005 to December 2011. In this study, 17 of the 121 patients were excluded due to loss during follow-up or for not having undergone a postoperative computed tomographic (CT) scan, and 3 patients were excluded due to an isolated iliac artery aneurysm. CT scans were scheduled at months 1, 6, and 12, and annually thereafter. Aneurysm size was defined by the minor axis on the largest axial cut of the aneurysm on a two-dimensional CT scan. Sac regression was defined as a reduction in the diameter of more than 5 mm. Results Sac regression was observed during follow-up in 39 of the 101 patients. There was 1 regression in 87 patients (1%) at 1 month, 18 in 62 patients at 6 months (29%), 26 regressions in 44 patients (59%) at 12 months, and 18 regressions in 34 patients (53%) at 24 months. After multivariate analysis, the absence of endoleaks was the only factor associated with sac regression (hazard ratio, 3.620; confidence interval, 1.692-7.747; p = 0.001). Conclusion Sac regression over 5 mm is associated with current or previous endoleaks after EVAR. Continued surveillance is necessary in all patients after EVAR to prevent late complications.