Effect Of Branch Length And Tortuosity On The Outcomes Of Branched Endovascular Repair Of Thoracoabdominal Aneurysms Using Self Expandable bridging stent-graft.

Abstract Objective To investigate the effect of length and tortuosity of directional branches on the mid-term outcomes of branched endovascular aneurysm repair (BEVAR) for thoracoabdominal aortic aneurysms (TAAA). Methods We retrospectively reviewed single-center data on consecutive patients undergoing BEVAR for TAAA from 2015 to 2019. Three-dimensional computed tomography angiogram reconstructions (Aquarius iNtuition software, Foster City, CA-USA) of the first post-operative imaging were used to measure the branch total-length (TL), vertical-length (VL) and tortuosity index (TI). Branch TL was measured as the centerline distance between the branch proximal radiopaque marker and the distal edge of the bridging stent; the VL was measured as the centerline distance between the branch distal radiopaque marker and the origin of the target artery. TI was measured based on Society for Vascular Surgery (SVS) reporting standard. The primary endpoint was freedom from branch instability, defined as any branch-related death, occlusion, rupture, or any reintervention for stenosis, endoleak or disconnection. Cox proportional hazards were used to identify predictors of branch instability. A penalized spline function was used to identify the relationship between branch instability and branch TL and VL. Results The post-implantation analysis was conducted on 32 TAAs (Extent I-III: n=18, 56%; Extent IV: n=14, 44%), with 123 arteries included through a directional branch. A covered self-expanding bridging stent was used in all cases. Intraoperative reinforcement with an additional bare-metal stent (BMS) was performed in 85 (69%) cases. Overall freedom from branch instability at 3 years was 88% (95%CI 81-94). There were 5 occlusions and 8 branch-related endoleaks. A concomitant endoleak and severe stenosis requiring intervention occurred in 3 cases. The Cox model with splines showed that the minimal risk of branch instability was achieved with a branch TL of 60-100 mm (P=.002) and a branch VL of 25-50 mm (P=.038). A TI >1.15 was a predictor of branch complications (HR 8.6, 95%CI 2.4-31.4; P 1.15 (HR 6.81, 95%CI 2.17-27.33; P 100 mm (P=.002) were significantly associated with branch instability. Conclusion Branch length and tortuosity index seems to play an important role in BEVAR outcomes. The lowest branch instability rates were obtained with a branch TL between 60 and 100 mm, and this should be considered during planning and implantation. A branch TI greater than 1.15 may require a more strict monitoring in order to prevent mid and long term complications.