Predictive Factors for Abdominal Aortic Aneurysm Shrinkage One Year after Successful Endovascular Aneurysm Repair

Background Often, we experience cases of aneurysm shrinkage and no aneurysm shrinkage after successful endovascular aortic aneurysm repair, without postoperative endoleaks. We studied these cases to ascertain the predictive factors for aneurysm shrinkage. Methods From 2007 to 2014, we selected 255 cases that comprised aneurysm shrinkage (>4 mm) and no-shrinkage cases (shrinkage from 0 to 4 mm). Excluding 36 cases of endoleaks, 43 cases without 1-year follow-up computed tomography scan, and 3 cases of aortic dissection, we assessed 93 cases of aneurysm shrinkage (S group) and 80 cases of no aneurysm shrinkage (N group) at 1-year follow-up. Results No significant differences were found in sex, comorbidities (diabetes mellitus, chronic kidney disease, hemodialysis, and malignancy), and medications (antiplatelet drugs, anticoagulant drugs, steroids, and statins). Advanced age was a strong negative predictive factor for aneurysm shrinkage (N: 75.0 ± 1.0 vs. S: 72.1 ± 0.9 years; P  = 0.023), and intraoperative endoleaks were more frequent in the N group (N: 31.3 vs. S: 9.7%; P  = 0.001). Neck thrombus was more likely in the N group (N: 17.5 vs. S: 7.5%; P  = 0.045), but it had a strong correlation with intraoperative endoleaks ( P  = 0.008). In the multivariate analysis, patient age and intraoperative endoleaks were predictive factors for aneurysm shrinkage. Conclusions Advanced age and intraoperative endoleaks were negative predictive factors for aneurysm shrinkage at 1-year follow-up after successful endovascular treatment without postoperative endoleaks.