Nationwide Analysis of Persistent Type II Endoleak and Late Outcomes of Endovascular Abdominal Aortic Aneurysm Repair in Japan: A Propensity-Matched Analysis

Background: We reviewed the results of endovascular aneurysm repair in patients from the Japanese Committee for Stentgraft Management registry to determine the significance of persistent type II endoleak (p-T2EL) and the risk of late adverse events, including aneurysm sac enlargement. Methods: The prospectively captured medical records of 17 099 patients <75 years of age who underwent endovascular aneurysm repair for abdominal aortic aneurysm from 2006 to 2015 were reviewed. Patients were divided into 2 groups (with or without p-T2EL) and compared to examine the correlation between p-T2EL and the occurrence of aneurysm sac enlargement after endovascular aneurysm repair. Results: Of the patients, 4957 (29.0%) had p-T2EL and 12 142 (71.0%) had no p-T2EL (non-T2EL). Mean age was significantly higher (P<0.001), and there were fewer men (P<0.001) in the p-T2EL group. Among comorbidities, hypertension (P=0.019) and chronic kidney disease (P=0.040) were more prevalent and respiratory disorders were less prevalent (P<0.001) in the p-T2EL group. From each group, 4957 patients were matched according to propensity score to adjust for differences in patient characteristics. The cumulative incidence rates of abdominal aortic aneurysm-related mortality (p-T2EL: 52 of 4957 [1.0%] versus non-T2EL: 21 of 12 142 [0.2%]), rupture (p-T2EL: 38 of 4957 [0.8%] versus non-T2EL: 13 of 12 142 [0.1%]), sac enlargement (≥5 mm; p-T2EL: 1359 of 4957 [27.4%] versus non-T2EL: 332 of 12 142 [2.7%]), and reintervention (p-T2EL: 739 of 4957 [14.9%] versus non-T2EL: 91 of 12 142 [0.7%]) were significantly higher in the p-T2EL than the nonpT2EL group (P<0.001). Propensity score matching yielded higher estimated incremental risk, including abdominal aortic aneurysm-related mortality, rupture, sac enlargement (≥5 mm), and reintervention for p-T2EL (P<0.001). Cox regression analysis revealed older age (P=0.010), proximal neck diameter (P=0.003), and chronic kidney disease (P<0.001) as independent positive predictors and male sex as an independent negative predictor (P=0.015) of sac enlargement. Conclusions: The Japanese Committee for Stentgraft Management registry data show a correlation between p-T2EL and late adverse events, including aneurysm sac enlargement, reintervention, rupture, and abdominal aortic aneurysm-related mortality after endovascular aneurysm repair. Besides p-T2EL, older age, female sex, chronic kidney disease, and dilated proximal neck were associated with sac enlargement.