Postdissection Aortic Aneurysm Sac Enlargement After Fenestrated and Branched Endovascular Repair

Aneurysm sac changes after fenestrated-branched endovascular aneurysm repair (FBEVAR) for postdissection thoracoabdominal aortic aneurysms (PDTAAs) are poorly understood. Partial thrombosis of the false lumen and endoleaks may impair sac regression. To characterize sac changes after FBEVAR for PDTAAs, this study examined midterm results and predictors for sac enlargement. FBEVARs performed for PDTAAs in 10 physician-sponsored investigational device exemption studies from 2008 to 2023 were analyzed. The maximum aortic aneurysm diameter was compared between the 30-day computed tomography angiogram and follow-up imaging studies. Aneurysm sac enlargement was defined as an increase in diameter of at least 5 mm. Kaplan-Meier curves and Cox regression were used to evaluate sac enlargement and midterm FBEVAR outcomes. Among 3296 FBEVARs, 290 patients (72.4% male; median age, 68.4 years) were treated for PDTAAs. Most aneurysms treated were extents II (72%) and III (12%). The mean aneurysm diameter was 66.5 ± 11.2 mm. Mortality at 30 days was 1.4%. At a mean follow-up of 2.9 ± 1.9 years, at least 1 follow-up imaging study revealed sac enlargement in 43 patients (15%), sac regression in 115 patients (40%), and neither enlargement nor regression in 137 patients (47%); 5 (2%) had expansion and regression. Freedom from aneurysm sac enlargement was 93%, 82%, and 80% at 1, 3, and 5 years, respectively. Overall, endoleaks were detected in 27 patients (63%) with sac enlargement and 143 patients (58%) without enlargement (P = .54). Sac enlargement was significantly more frequent among older patients (mean age at the index procedure, 70.2 ± 8.9 vs 66.5 ± 11 years; P = .04; Fig 1) and those with type II endoleaks at 1 year (74% vs 52%; P = .031; Fig 2). Cox regression revealed age >70 years at baseline (hazard ratio [HR], 2.146; 95% confidence interval [CI], 1.167-3.944; P = .010) and the presence of type II endoleak at 1 year (HR, 2.25; 95% CI, 1.07-4.79; P = .032), which were independent predictors for sac enlargement. Patient survival was 92%, 81%, and 68% at 1, 3, and 5 years, respectively. Cumulative target vessel instability was 7% and aorta-related mortality 2% at 5 years. At least 50% of patients required secondary interventions. Sac enlargement did not affect patient survival. Aneurysm sac enlargement occurs in one-fifth of patients after FBEVAR for PDTAAs. Sac enlargement is more frequent among patients older than 70 years and those with persistent type II endoleaks at 1 year. Aneurysm-related mortality at 5 years remains low, and overall survival was not associated with sac enlargement.Fig 2Freedom from aneurysm sac enlargement (≥5 mm in maximum diameter) stratified by the presence of type II endoleak after FBEVAR. US-ARC FBEVARs performed for PDTAAs 2008-2023 (n = 290). Sac enlargement was significantly more frequent among patients with type II endoleak at 1 year (74% vs 52%; P = .031). The shaded areas indicate 70% confidence limits.