The Combined Use of a Distal Self-Expandable and Proximal Balloon-Expandable Stent Graft in Bridging Hostile Renal Arteries in Thoracoabdominal Branched Endografting

Background: To evaluate early/midterm outcomes of a specific configuration of a bridging stent graft—that is a distal self-expandable (SE) stent graft combined with proximal balloon-expandable (BE) one—in hostile renal artery (RA) anatomy in branched thoracoabdominal aneurysm (TAAA) repair. Methods: Between 2010 and 2019, all TAAAs undergoing fenestrated and branched endografting (FB-EVAR) were prospectively collected. Preoperative, procedural, and postoperative data of RAs accommodated by branch design and patent at the completion angiography were retrospectively analyzed. Hostile RA anatomy included upward (type B) and downward + upward (type D) orientations. Type B and D RAs treated by the combination of an SE + BE stent graft as a bridging stent (BE + SE group) were compared with RAs treated by a BE stent graft only (BE group). RA occlusion, reinterventions, and branch instability were assessed. Results: Over a total of 112 TAAAs undergoing FB-EVAR, 189 RAs were treated by fenestrations (113–60%) and branches (76–40%). Among the 66 (86%) RAs accommodated by branch and patent at completion angiography, 55 had a type B/D orientation. BE stent grafts were used in 15/55 (27%) RAs and SE + BE in 40/55 (73%). At a median follow-up of 12 (8) months, 5/55 (9%) RAs occluded: 4/15 (27%) in the BE group and 1/40(2.5%) in the SE + BE group (P: 0.017). RA patency was 83 ± 5% at 24 months. The SE + BE group had higher patency than the BE group (90 ± 5% vs. 68 ± 5% at 12 months; P: 0.039). Overall freedom from RA-related reinterventions was 87 ± 5% at 24 months. Six (9%) RAs required reinterventions: 4/15 (27%) in the BE group and 2/40 (5%) in the BE + SE group (P: 0.041). RAs managed by an SE + BE stent graft had lower reinterventions than RAs treated by a BE stent graft only (93 ± 5% vs. 76 ± 5% at 12 months; P: 0.01). Freedom from branch instability was 78 ± 5% at 24 months, with 8 overall cases (12%) occurring—5/15 (33.3%) in the BE group versus 3/40 (7.5%) in the SE + BE group (P: 0.02). RAs managed by an SE + BE stent graft had lower branch instability than RAs treated only by a BE stent graft (BE: 68 ± 5% vs. SE + BE: 80 ± 5% at 12 months; P: 0.02). Conclusions: In hostile renal anatomy, the combination of a distal SE and proximal BE stent graft as a bridging stent in branched endografting is safe and effective with lower rates of occlusion, reinterventions, and branch instability at midterm follow-up compared with a BE stent graft alone.