Hybrid Stent Graft Technique in Bridging Hostile Renal Arteries in Thoraco-abdominal Branched Endografting

Objective: Target artery patency is crucial for fenestrated and branched endovascular aortic repair (FB-EVAR) in thoraco-abdominal aortic aneurysms (TAAAs). Occlusions more frequently occur in the renal arteries (RAs) than in the coeliac and superior mesenteric arteries, especially in patients with hostile anatomy treated by B-EVAR. This study aimed to report RA outcomes using a hybrid bridging stent graft technique with distal self expandable (SE) combined with proximal balloon expandable (BE) stent graft during B-EVAR with hostile RA anatomies.

Methods: Clinical data from consecutive patients treated for TAAA by FB-EVAR in three aortic centres (two in the USA, one in Europe) from 2016 to 2022 were collected prospectively. RA orientation was defined as hostile in case of upward (type B) or downward + upward (type D) orientation. Hostile RAs accommodated by B-EVAR and combination of SE + BE stent grafts were evaluated retrospectively. Intra-operative RA related complications, technical success (TS), and branch occlusions were assessed as early outcomes. Primary and secondary RA patency, freedom from RA related re-interventions, and freedom from RA instability were assessed during follow up.

Results: Of 584 TAAAs managed by FB-EVAR, 83 patients (14.2%) had 125 hostile RAs (type B, 45.6%; type D, 54.4%) managed by B-EVAR with hybrid SE + BE stent grafts. Intra-operative complications occurred in three RAs (2.4%), including two dissections and one disconnection, all successfully managed with additional stents. TS was achieved in all cases, with no RA occlusions at 30 days. The median follow up was 21 (interquartile range 4, 38) months. Estimated three year RA primary patency was 97 ± 2%. Re-interventions were performed in five RAs (4.0%), including two RA branch embolisations for bleeding, two catheter thrombectomies with stent relining (bilateral occlusion in one patient), and one revision of type Ic endoleak. Freedom from RA related re-interventions and RA instability was 95 ± 2% and 91 ± 3% at three years, respectively. RA secondary patency was 99 ± 1% at three years.

Conclusion: In hostile RA anatomies, a combination of distal SE and proximal BE stent grafts as bridging stenting in B-EVAR is safe and effective, with low rates of occlusion, re-interventions, and branch instability at midterm follow up.