Influence of warfarin therapy on the occurrence of postoperative endoleaks and aneurysm sac enlargement after endovascular abdominal aortic aneurysm repair

Objectives: This study aims to determine whether warfarin therapy influences the occurrence of endoleaks or aneurysm sac enlargement after endovascular aortic repair (EVAR). Methods: A total of 367 patients who underwent EVAR for abdominal aortic aneurysm between 2007 and 2013 were recruited for this study. Satisfactory follow-up data including completed computed tomography scan follow-up for more than 2 years were available for 209 patients, and the mean follow-up time was 37 ± 12 months. Twenty-nine (16%) patients were on warfarin therapy (warfarin group), whereas 180 (84%) patients were not on warfarin therapy (control group). Results: Two- and four-year freedom rates for persistent type II endoleaks were significantly lower in patients of the warfarin group compared with the control group (85 and 49% vs 93 and 91%, respectively; P = 0.0001). Similarly, 2- and 4-year freedom rates for sac enlargement (>5 mm) were significantly lower in patients of the warfarin group compared with the control group (83 and 61% vs 92 and 82%, respectively; P = 0.0036). Using Cox regression analysis, the warfarin therapy was identified to be an independent positive predictor of sac enlargement after EVAR [hazard ratio (HR): 2.4; 95% confidence interval (CI): 1.08-5.40; P = 0.032], together with persistent type II endoleak. Warfarin therapy was also an independent predictor for persistent type II endoleak (HR: 3.7; 95% CI: 1.81-7.41; P < 0.0001) together with the number of patent lumbar arteries. Conclusions: Results suggested that warfarin therapy was significantly associated with an increased risk for persistent II endoleak and sac enlargement after EVAR.