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 one 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 renal artery bridging lengths (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, the mortality rate 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 one 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 one year results. The E-nside may require shorter thoracic aortic coverage and bridging length for the renal arteries, and less frequent implantation of a concomitant proximal thoracic or distal abdominal bifurcated endograft. However, these aspects did not determine significant differences in clinical outcomes.