The combined use of distal self-expandable and proximal balloon-expandable stentgraft in bridging hostile renal arteries in thoracoabdominal branched endografting.

PURPOSE: To evaluate early/mid-term outcomes of a specific configuration of bridging stentgraft - i.e. distal self-expandable stent-graft (SE) combined with proximal balloon (BE) expandable one - in hostile renal arteries (RAs) anatomy in branched thoracoabdominal aneurysms (TAAAs) repair. METHODS: Between 2010 and 2019, all TAAAs undergoing FB-EVAR were prospectively collected. Pre-operative, procedural and post-operative data of RAs accommodated by branch design and patent at the completion angiography, were retrospectively analyzed. Hostile renal artery anatomy included upward (typeB) and downward + upward (typeD) orientations. Type B and D RAs treated by the combination of SE+BE stent-graft as bridging stent (BE+SE group), were compared with RAs treated by balloon expandable stent-graft only (BE-group). Renal artery 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 BE-group and 1/40(2.5%) in the SE+BE group (p:.017). RAs patency was 83+5% at 24months. SE+BE group had higher patency than BE group (90+5%vs.68+5% at 12 months; p:.039). Overall freedom from RA-related reinterventions was 87+5%) at 24months. Six(9%) RAs required reinterventions: 4/15(27%) in BE-group and 2/40(5%) in BE+SE group (p:.041). Renal arteries managed by SE+BE stent-graft had lower reinterventions than RAs treated by BE stent-graft only (93+5%vs.76+5% at 12 months; p:.01). Freedom from branch instability was 78+5%) at 24months, with 8 overall cases (12%) occurring - 5/15(33.3%) in BE group vs 3/40(7.5%) in SE+BE group (p:.02). Renal arteries managed by SE+BE stent-graft had lower branch instability than RAs treated only by BE stent-graft (BE:68 +5%vs.SE+BE:80+5% at 12months; p:.02). CONCLUSIONS: In hostile renal anatomy, the combination of distal SE and proximal BE stent-graft as bridging stent in branched endografting is safe and effective with lower rates of occlusion, reinterventions and branch instability at mid-term follow-up compared with BE stent-graft alone.