High Incidence of Type 2 Endoleak and Low Associated Adverse Events in the Vascular Quality Initiative Linked to Medicare Claims.

INTRODUCTION: Type 2 endoleak (T2EL) is the most common adverse finding on post-operative surveillance after endovascular aortic aneurysm repair (EVAR). A low rate of aneurysm related-mortality with T2EL has been established. However, the optimal management strategy and the efficacy of reintervention remains controversial. This study used data from the Vascular Quality Initiative linked to Medicare claims (VQI-Medicare) to evaluate T2LE in a real-world cohort.

METHODS: This retrospective review of EVAR procedures in VQI-Medicare included patients undergoing their first EVAR procedure between 2015 and 2017. Patients with an endoleak other than T2EL on completion angiogram and those without VQI imaging follow-up were excluded. Patients without Medicare part A or part B enrollment at the time of procedure or without 1-year complete Medicare follow up data were also excluded. The exposure variable was T2EL, defined as any branch vessel flow detected within the first post-operative year. Outcomes of interest were mortality, reintervention, T2EL-related reintervention, post EVAR imaging, and T2EL behavior including spontaneous resolution, aneurysm sac regression, and resolution post reintervention. The association of prophylactic branch vessel embolization (PBE) with T2EL resolution and aneurysm sac regression was also evaluated.

RESULTS: In a final cohort of 5,534 patients, 1,372 (24.7%) had an identified T2EL and 4,162 (75.2%) did not. The median age of patients with and without T2EL were 77 and 75 years, respectively. There were no differences in mortality, imaging, reintervention, or T2EL-related reintervention at three years post procedure for patients with T2EL. Aneurysm sac diameter decreased by 4mm (range, 9mm - 0mm decrease) in the total cohort. Patients with IMA-based T2ELhad the smallest decrease in aneurysm diameter (median 1mm decrease compared to 1.5mm for accessory renal artery-based T2EL, 2mm for multiple feeding vessel-based T2EL, and 4mm for lumbar artery-based T2EL p<0.001). Spontaneous resolution occurred in 73.7% of patients (n=809). T2EL with evidence of multiple feeding vessels were associated with the lowest rate of spontaneous resolution (n=51, 54.9%), compared to those with a single identified feeding vessel of IMA (n=99, 60.0%), lumbar artery (n=655, 77.7%), or accessory renal artery (n=31, 79.5%) (p<0.001). PBE was performed in 84 patients. Patients who underwent PBE and were without detectable T2EL after EVAR had the greatest rate of sac regression at follow up (7mm decrease) compared to baseline.

CONCLUSIONS: T2EL after EVAR is associated with high rates of spontaneous resolution, low rates of aneurysm sac growth, and no evidence of increased early mortality or reintervention. Prophylactic branch vessel embolization in conjunction with EVAR may be indicated in some circumstances.