Outcomes utilizing inverted iliac limb bifurcate components in fenestrated/branched endografting

Abstract

Utilization of standard bifurcate pieces in fenestrated/branched endovascular aortic repair (F/BEVAR) requires adequate length from the lowest branch or fenestration to the aortic bifurcation. In patients with prior aortic surgery, the aortic bifurcation is often artificially established in a more proximal position, compromising the infrarenal length, which hinders the placement of a standard bifurcate component below the fenestrated/branched component. Short bifurcate bodies utilizing an inverted contralateral limb have been purpose-built to address this challenge. However, reported outcomes for this device remain limited, with specific concerns about the durability of the inverted iliac limb sealing region. We sought to evaluate outcomes of F/BEVAR utilizing an investigational inverted iliac limb bifurcate, manufactured by Cook Medical. This study was a retrospective review of prospectively maintained data from the US-Aortic Research Consortium (US-ARC) from 2005-2022. Patients were included if they underwent F/BEVAR for thoracoabdominal or complex abdominal aortic aneurysms. Patients were excluded if they did not have a bifurcate device placed. Patients were then compared based on the utilization of an inverted iliac limb or standard bifurcate component. The primary outcome for this study was technical success. Secondary outcomes included 30-day mortality, freedom from ischemic leg complications, freedom from type 1 endoleaks (T1ELs), freedom from type 2 endoleaks (T2ELs), freedom from type 3 endoleaks (T3ELs), and graft component separations. A total of 1,944 patients met study criteria with 442 (22.8%) inverted iliac limb bifurcates and 1,502 (77.2%) standard bifurcates. Patients who received inverted iliac limbs were more likely to have had prior aortic surgery (63.8% versus 28.5%, P<.001). Patients receiving inverted iliac limbs had longer procedure times (265 minutes [IQR 201-342 minutes] versus 241 minutes [IQR 186-313 minutes], P<.001), more contrast usage (89 mL [IQR 55-135] versus 109 mL [IQR 75-156 mL], P<.001), and higher estimated blood loss (250 mL [IQR 150-500 mL] versus 250 mL [IQR 110-400 mL], P=.042). There were no differences in rates of technical success (97.3% versus 96.1%, P=.310), rates of endoleaks upon completion of the case (18.0% versus 21.4%, P=.123) or 30-day mortality (1.8% versus 2.5%, P=.466) between patients receiving inverted bifurcates and standard bifurcated components. There were no differences in cumulative survival, freedom from limb ischemia, freedom from aneurysm rupture, and freedom from T3ELs over the course of 5 years between patients receiving inverted bifurcates and standard bifurcated components. Patients with inverted iliac limb bifurcate components had decreased freedom from reinterventions, T1ELs, and T2ELs. After adjustment of potential confounders, the use of an inverted iliac limb was not associated with reinterventions (HR 1.044, 95 % CI 0.849-1.285, P=.682). There was a total of 2 (0.1%) component separations of the bifurcate component from the fenestrated/branched component over the study period, both of which occurred in the standard bifurcate components. The use of investigational inverted iliac limb bifurcate components is a safe option with favorable mid-term outcomes in patients who are not anatomic candidates for standard bifurcate components. Patients undergoing investigational inverted iliac limb bifurcate component implantation had decreased freedom from reinterventions which likely corresponds to the complexity of repair associated with them.