1-year outcomes from the pivotal trial of a four-branch off-the shelf solution to treat pararenal and Extent IV thoracoabdominal aortic aneurysms

To report 1-year primary-arm outcomes of the GORE EXCLUDER Thoracoabdominal Branch Endoprosthesis (TAMBE) pivotal trial. The multicenter, nonrandomized, prospective study included patients with Extent IV thoracoabdominal aortic aneurysms (TAAA) and pararenal aortic aneurysms (PRAA). All-cause and adjudicated lesion-related mortality were assessed at 12-months. Core-lab-reported, imaging-dependent outcomes included aneurysm size, endoleaks assessed through 1-year follow-up window, and target vessel instability (TVI; defined as occlusion, stenosis, Type Ic/IIIc endoleak, or reintervention) at 1 year. One hundred and two patients were treated; 59 patients had an Extent IV TAAA aneurysm and 43 had a PRAA. The mean maximum aneurysm diameter was 59.4±7.8 mm. At 1 year, eight patients were lost to follow-up and six patients died (1 device-related, 1 procedure-related, and 4 unrelated causes). No lesion-related mortality occurred. Freedom from all-cause mortality was 94.1±2.3%. The 1-year combined freedom from "clinically significant reintervention" and lesion-related mortality was achieved in 78.7% and 60.5% of Extent IV TAAA and PRAA patients, respectively (P=0.09). At least one target vessel branch occlusion occurred in 14.7% of patients through 1 year of follow-up. At the vessel level, freedom from TVI at 1 year was 94.2±1.2% (celiac 99.0±1.0%, superior mesenteric 97.1±1.7%, right renal 90.8±2.9%, left renal 89.8±3.1%). Acute kidney injury requiring dialysis occurred in three patients (n=2 permanent, n=1 temporary) through 1 year. Occlusion of the renal arteries occurred more often in renal artery diameters <5 mm (odds ratio [OR]=3.04; 95% CI: 1.08, 8.54) and pararenal aneurysms (OR=2.85; 95% CI: 0.88, 9.25, statistically insignificant). Of the 22 reinterventions in 15 patients, 16 (73%) reinterventions were classified as minor; 13 (81%) for target vessel complications and 3 (19%) for Type II endoleaks. Device- or procedure-related major reinterventions in six patients included thrombectomy or thrombolysis for target vessel occlusion (n=5) and one exploratory laparotomy following procedural aortic rupture. No Type I/III endoleaks were identified (Core lab) through 1 year. Aortic enlargement (>5 mm) occurred in 5 patients (6.0%). Aneurysm shrinkage (>5 mm) occurred in 20 patients (23.8%). Aortic component fractures identified in 3 patients (3.6%) were clinically insignificant. While mortality remains low 1 year after treatment with the TAMBE device for Extent IV and pararenal aneurysms, renal artery occlusion was the predominant adverse event and was primarily associated with PRAA and smaller renal vessel diameters. During extended follow-up, attention should be focused on renal branch assessment to identify patients at risk for occlusion.