Outcomes of Off the Shelf Outer Branched Versus Inner Branched Endografts in the Treatment of Thoraco-abdominal Aortic Aneurysm in the B.R.I.O. (BRanched Inner – Outer) Study Group

Objective This study aimed to compare two commercially available off the shelf branched endografts for thoraco-abdominal aortic aneurysm (TAAA) repair, namely the E-nside (Artivion) and Zenith t-Branch (Cook Medical) devices. Methods This multicentre retrospective study (2020 – 2023) included patients treated by branched endovascular aortic repair (BEVAR) for TAAA using the inner branched E-nside or the outer branched t-Branch. Endpoints were 30 day technical success and major adverse events (MAEs) as well as 1 year freedom from target vessel instability and main endograft instability. Results The study included 163 patients: 79 (307 target vessels) treated with E-nside and 84 (325 target vessels) with t-branch. Aneurysm extent was I – III in 91 patients (55.8%; 47% of E-nside and 66% of t-Branch) and IV in 72 patients (44.2%; 53% of E-nside and 34% of t-Branch) (p = .011). An adjunctive proximal thoracic endograft was used in 43% of E-nside vs. 69% of t-Branch (p < .001), with less frequent thoracic endografting (14% vs. 76%; p < .001) and shorter length of coverage (p = .024) in extent IV TAAA treated by E-nside. E-nside cases had shorter bridging length of renal arteries (66 ± 17 mm vs. 76 ± 20 mm; p < .010) and less frequent use of a distal bifurcated endograft (53% vs. 80%; p < .001). Comparing 30 day results, mortality was 1% vs. 2% (p = .62), any MAE occurred in 18% vs. 21% (p = .55), the stroke rate was 3% vs. 0% (p = .23), and the elective spinal cord ischaemia rate was 5% vs. 8% (p = .40) for E-nside and t-Branch, respectively. At 1 year, freedom from target vessel instability was 96 ± 3% for E-nside and 95 ± 3% for t-Branch (p = .58), and freedom from endograft instability was 98 ± 2% vs. 97 ± 3% (p = .46) respectively. Conclusion Both off the shelf devices provided excellent early and 1 year results. The E-nside may require shorter thoracic aorta coverage and bridging length for the renal arteries, and less frequent implantation of concomitant proximal thoracic or distal abdominal bifurcated endograft. However, these aspects did not determine significant differences in clinical outcomes.