SS01 - 1-year Results from the Pivotal Trial of a 4-Branch Thoracoabdominal Branch Endoprosthesis

Objectives: This study reports the 1-year outcomes from the primary arm of the GORE EXCLUDER Thoracoabdominal Branch Endoprosthesis (TAMBE) pivotal trial.

Methods: The multicenter, nonrandomized, prospective study of the TAMBE device included patients enrolled in the primary study arm with extent IV thoracoabdominal aortic aneurysms and pararenal aortic aneurysms. The clinical events committee adjudicated the following protocol-defined 12-month outcomes: clinically significant reintervention and lesion-related mortality. Additional core-lab-reported outcomes included aneurysm size, endoleaks, and target vessel instability (TVI) defined as occlusion, stenosis, Type Ic/IIIc endoleak, or reintervention.

Results: One hundred and two patients were treated in the primary arm and 88 patients were evaluated at the 1-year window. Eight patients were lost to follow-up, and six patients died during the first year: one device-related and five from unrelated causes. Freedom from all-cause mortality at 1 year was 94.1%±SE 2.3%. At least one target vessel branch occlusion occurred in 14.7% (14/95) of patients through 1 year. Freedom from TVI was 94.2%±SE 1.2% at 1 year (celiac artery 99.0%± SE 1.0%, superior mesenteric artery 97.1%±SE 1.7%, left renal artery 90.8%±SE 2.9%, right renal artery 89.8%± SE 3.1%) (Figure 1). Acute kidney injury requiring dialysis occurred in 3 patients (n=2 permanent, n=1 temporary) through 1 year. Occlusion of the renal arteries more commonly occurred in pararenal aneurysms (OR=2.85; 95% CI: 0.88, 9.25) and renal artery diameters < 5 mm (OR=0.33; 95% CI: 0.12, 0.92). Fifteen patients (15.6%, n=96) had 22 reinterventions performed. Sixteen (73%) reinterventions were classified as minor and included 13 (81%) for target vessel complications and 3 (19%) for Type II endoleaks. Device- or procedure-related major reinterventions (5.2%, 5/96) included either thrombectomy (2.1%, 2/96) or thrombolysis (2.1%, 2/96) for target vessel occlusion and one exploratory laparotomy following procedural aortic rupture. There were no major endoleaks (I or III) reported through 1 year. Aortic enlargement (>5 mm) occurred in 5 (6.0%) patients, with aneurysm shrinkage (>5 mm) occurring in 20 (23.8%, n=84) patients. Aortic component fractures were identified in 3 patients (3.6%, n=83) and were not clinically significant.

Conclusions: While mortality remains low 1 year after treatment with the TAMBE device for extent IV and pararenal aneurysms, renal artery occlusion predominates among the adverse events primarily associated with pararenal aneurysms and smaller renal vessel diameters. During extended follow-up, attention should be focused on renal branch assessment to identify patients at risk for occlusion.

Figure 1: Target Vessel Instability of Branch Vessels