Aneurysm Extent-based Mortality Differences in Complex Endovascular Repair of Thoracoabdominal Aneurysms in the VQI and the United States Aortic Research Consortium.

INTRODUCTION: Endovascular management of thoracoabdominal aneurysms (TAAA) is becoming more common. Technological advances including custom devices under the Physician-Sponsored Investigational Device Exemption (PS-IDE), physician modified devices (PMEG), and parallel stenting techniques have expanded the extent of disease that is amenable to endovascular treatment. Patients within the PS-IDE studies are a highly selected group of patients, whereas patients treated with PMEG as captured within the Society of Vascular Surgery Vascular Quality Initiative (SVS-VQI) represent a real-world experience. Research within both the SVS VQI on PMEG and the United States Aortic Research Consortium (US ARC) has demonstrated a relationship between extent of aneurysmal disease and mortality following complex endovascular TAAA repair, but no direct comparison of these cohorts has been conducted. In this study, we sought to compare outcomes of custom PS-IDE devices to off-label uses of commercially available devices for the endovascular management of thoracoabdominal aortic aneurysms.

METHODS: A retrospective review of patients presenting for elective endovascular TAAA repair for asymptomatic disease between 2011 and 2019 was conducted within both the SVS VQI registry and the US-ARC. Patients within the SVS VQI registry were treated with either physician modified endografts (PMEG) or with parallel stenting techniques. Patients within the US-ARC were treated with physician-sponsored investigational device exception custom devices. Extent of aneurysm disease was defined by the deployment zones documented for the devices entered in the registry using Crawford extents I-V. Primary outcomes were 30-day and 1 year mortality.

RESULTS: A total of 3,212 patients were included in the study: 1,571 PMEG/Parallel stenting within the VQI registry, and 1,641 with PS-IDE within the US-ARC database. The majority of patients presented with Extent IV aneurysms (57%, n=1,827), with Extent IV aneurysms being slightly more prevalent within the US-ARC cohort. Maximal aneurysm diameter within each extent did not vary between the US-ARC and VQI cohorts. Across all patients, 30-day mortality was 4.4% and 1 year mortality was 12.2%. Unadjusted mortality at 30-days was 6.7% within the VQI, and 2.2% in the US-ARC (p<0.001). Unadjusted 1-year mortality was 14.3% within the VQI and 10.2% within the US-ARC (p<0.001). When adjusted for aneurysm extent, similar differences in 30-day and 1-year survival were identified.

CONCLUSIONS: Patients treated in PS-IDE studies had better 30-day and one-year survival compared to those treated with similar extent of disease using off label approaches in a real-world registry. These differences are complex and likely associated with a number of factors including arterial anatomy, patient comorbidities, device construct, volume-outcomes as well as complex and unmeasurable surgeon/patient specific factors.