Change in Abdominal Aortic Aneurysm Sac Diameter After Endovascular Repair: A Single-Center Experience From Taiwan

Purpose: The purpose of this study was to investigate the change in the diameter of infrarenal abdominal aortic aneurysm (AAA) sacs after endovascular aortic repair (EVAR) in Taiwanese patients and to depict its association with clinical outcomes. Materials and Methods: This retrospective cohort study was conducted on patients who underwent EVAR for infrarenal AAA between January 2011 and December 2016. All preoperative and follow-up computed tomography (CT) images were reviewed. Postoperative CT angiography was arranged after 1 month and annually thereafter. The maximal diameter on the axial plane and the maximal diameter perpendicular to the centerline on the coronal and sagittal planes were measured. The study examined post-EVAR sac diameter change over time and compared the differences in adverse events (AEs) among groups. Results: The survey included a total of 191 patients with a median follow-up duration of 2.5 (interquartile range: 1.1-2.9) years. Overall survival rates at 1, 2, and 5 years were 92%, 81%, and 76%, respectively. According to their last CT scans, the patients were categorized into 3 groups as follows: shrinkage, stationary, and enlargement, which comprised 58 (30.4%), 118 (61.8%), and 15 (7.9%) patients, respectively. Pre-EVAR characteristics and sac diameters were similar among the groups. Sac shrinkage was exclusively observed in the first 2 years, whereas sac enlargement developed at all follow-up periods. Patients with sac enlargement had higher incidence rates of endoleaks, complications, and reintervention than the other groups. Conclusion: Based on our observations, post-EVAR sac shrinkage only occurs in the first 2 years; however, post-EVAR sacs may enlarge at any point and even after 5 years. In our study, patients with sac enlargement had higher rates of adverse events and reintervention.