OVER Trial Analysis Evaluates Predictors and Outcomes of Endoleaks in EVAR

December 2, 2015—In the Journal of Vascular Surgery (JVS), Brajesh K. Lal, MD, et al published an analysis that identifies characteristics, risk factors, and long-term outcome of endoleaks in patients treated with endovascular aneurysm repair (EVAR) in the Veterans Affairs Open Versus Endovascular Repair (OVER) trial of abdominal aortic aneurysms (2015;62:1394–1404). The randomized controlled OVER trial compared open repair and EVAR in standard-risk patients with infrarenal aortic aneurysms. 

According to the investigators, this is one of the most comprehensive and longest follow-up analyses of patients treated with aortic endografts. They found that endoleaks were common and negatively affected aneurysm diameter reduction. Delayed type II endoleaks were associated with late aneurysm diameter enlargement. Endoleaks and aneurysm diameter enlargement were not associated with excess mortality compared with those without these features, concluded the investigators in JVS.

As summarized in JVS, the OVER trial enrolled 881 patients, of whom 439 received successful EVAR. Logistic regression analysis was used to identify predictors for endoleaks and secondary interventions. Kaplan-Meier survival analysis, longitudinal plots, and generalized linear mixed models methods were used to describe time to endoleak detection, resolution, or death.

During a mean follow-up of 6.2 ± 2.4 years, 135 patients (30.5%) developed 187 endoleaks. Four patients with EVAR went on to rupture; not all of these four patients had an endoleak. Mortality between patients who did and did not develop endoleaks was not significantly different. 

The 187 endoleaks included 12% type I, 76% type II, 3% type III, 3% type IV, and 6% indeterminate. Patient demographics and vascular risk factors were not associated with endoleak development. The presence of endoleaks resulted in an increase in aneurysm diameter over time (P < .0001). Additionally, 53% of endoleaks resolved spontaneously, and 31.9% received secondary interventions. The initial aneurysm size independently predicted a need for secondary interventions (P < .0003). Delayed type II endoleaks (detected > 1 year after EVAR) were associated with aneurysm enlargement compared with early type II endoleaks. There was no difference in aneurysm size or length of survival between type II and other types of endoleak, reported the investigators in JVS.