Geometric changes over time in bridging stents after branched and fenestrated endovascular repair for thoracoabdominal aneurysm

Objective: The objective of this study was to assess long-term durability of bridging stents in branched and combined branched and fenestrated endovascular aneurysm repair (B/F-EVAR) for thoracoabdominal aortic aneurysm (TAAA) and pararenal abdominal aortic aneurysm. Methods: A retrospective database analysis was performed of patients treated by B/F-EVAR for TAAA. Computed tomography angiography images were analyzed to assess patency, bridging stent angulation and migration, aneurysm diameter, and migration of the endograft. Results: Twenty-eight patients with a median age of 70 years (interquartile range [IQR], 67-77 years) were included. Assisted technical success was 89%. Within 30 days postoperatively, five patients died. In the remaining 23 patients, median follow-up was 5.3 years (IQR, 2.9-7.2 years), and 1-, 3-, and 5-year estimated overall survival was 69%, 65%, and 44%, respectively. During follow-up, 12 of 47 (26%) branches occluded and 5 of 47 (11%) branches developed a 70% to 99% stenosis. The 1-, 3-, and 5-year estimated freedom from adverse events was 78%, 76%, and 59% for branch stents and 100%, 96%, and 90% for fenestration stents, respectively. The median distal bridging stent migration was 0.5 mm (IQR, −1.9 to 1.4; P >.05 mm). In 10 branches, migration >10 mm was seen, ranging from 14.1 mm sliding in to 23.0 mm sliding out. The angulation between branch and stent became 4 degrees more angulated (IQR, −14 to +2 degrees). In 23 branches, the angulation changed 10 degrees or more, leading to an occlusion in 7 branches, a 70% to 99% stenosis in 3 branches, and a 50% to 70% stenosis in 4 branches. In three cases, the endograft migrated >5 mm caudally, with a breach in a fenestration stent in one and a breach in a branch stent in another. Conclusions: The anatomic configuration of branches in B/F-EVAR of TAAAs and pararenal abdominal aortic aneurysms changes over time. The change in angle of branches and the bridging stent influences the likelihood of stenosis and occlusion. Follow-up of B/F-EVAR should include computed tomography angiography measurements of aortic diameter, endograft migration, target vessel stent length, and angulation to detect disconnection, stenosis, and occlusion.