Objective: The applicability of early sac shrinkage as a predictor of a low risk of late complications after endovascular aneurysm repair (EVAR) in Asian populations has not been validated. This study aimed to analyze early sac shrinkage and its relationship with late complications in Asian people using a Japanese multicenter database. We also assessed the impact of endoleaks. Methods: A retrospective analysis of 697 patients who had undergone EVAR of abdominal aortic aneurysms from 2008 to 2015 and were followed up for at least 1 year was conducted. Late complications were defined as any aneurysm-related events occurring >1 year after EVAR, including >5-mm aneurysm sac enlargements and any reinterventions performed. Endoleaks without any evidence of sac enlargement or a requirement for additional treatment were not considered late complications. Results: Early sac shrinkage, defined as a >5-mm-diameter decrease within 1 year of EVAR, occurred in 335 patients (48.1%); type I endoleaks (T1ELs) and isolated type II endoleaks (iT2ELs; type II endoleaks without evidence of other endoleaks) were observed in 4.0% and 29.4%, respectively. During the mean follow-up period of 45.5 months, 93 late complications (13.3%) occurred. Kaplan-Meier curve and log-rank analyses showed that early sac shrinkage was a significant predictor for a lower risk of late complications (P <.001). Multivariate analysis revealed that early sac shrinkage was independently associated with a lower risk of late complications (adjusted hazard ratio, 0.425; P =.004). Conversely, T1ELs and iT2ELs were positively associated with late complication (adjusted hazard ratio, 11.774 and 5.137, respectively; both P <.001). Subsequent multivariate analysis demonstrated that T1ELs and iT2ELs were negatively associated with early sac shrinkage (adjusted odds ratio, 0.102 and 0.285, respectively; both P <.001). Conclusions: Early sac shrinkage was associated with a low risk of late complications in Asian people and may be a good surrogate marker of durable success after EVAR. T1ELs and iT2ELs were negatively associated with early sac shrinkage and positively associated with late complications. Along with the high incidence of iT2ELs observed, T2ELs may be an important condition to consider after EVAR in the Asian population.
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