Effect of chronic oral anticoagulation with warfarin on the durability and outcomes of endovascular aortic aneurysm repair

Abstract

Endoleak after endovascular aortic aneurysm repair (EVAR) can affect the durability of the repair and lead to continued sac expansion, rupture, and the need for further endovascular or open surgical interventions. The purpose of this study was to determine whether chronic anticoagulation therapy with warfarin is associated with an increased incidence of endoleak and thus increased need for reintervention after EVAR. We reviewed the records of 401 consecutive patients who underwent EVAR at a single institution from 2003 until 2011. Patients on warfarin were compared with a control group not on warfarin. Primary endpoints included reintervention, defined as rupture, explant, or angiography; death from any cause; and a composite outcome of reintervention or death. The presence of an endoleak at last follow-up, identified by computed tomography or ultrasound scan, and increase of more than 5 mm in aneurysm sac size were secondary endpoints. Cox proportional hazards models were used to estimate the effect of warfarin use on the primary and secondary outcomes, controlling for age, gender, obesity, specific comorbidities, antiplatelet drugs, statin use, and urgency of EVAR. Three hundred sixty-three patients with a median follow-up period of 29 months had sufficient data for analysis. Warfarin use was not associated with an increased risk of any of the primary endpoints. Controlling for covariates and length of observation via proportional hazards models, the effect of warfarin remained insignificant. It was found, however, on regression analysis, that adverse outcomes were more prevalent after emergency EVAR and in patients deemed unfit for open surgical repair. Chronic oral anticoagulation does not appear to affect the incidence of endoleak after EVAR, nor does it impact the need for reintervention or degree of sac regression. We feel that warfarin may be safely used in post-EVAR patients. It appears that adverse long-term outcomes are more likely after emergency EVAR and in patients deemed unfit for open surgery.