Does chronic oral anticoagulation with warfarin affect durability of endovascular aortic aneurysm exclusion in a midterm follow-up?

Purpose: To evaluate the effect of oral anticoagulation on durability of endovascular aortic aneurysm repair (EVAR). Methods: Retrospective review was conducted of 182 consecutive EVAR patients (169 men; mean age 75.3 years, range 53-89) between 1999 and 2003. Patients on warfarin anticoagulation (WA, n=21; International Normalized Ratio of 2 to 3) were compared against a control group (CG) with no postoperative anticoagulation (n=161). Death, aneurysm rupture, and reintervention were considered primary endpoints, endoleaks, endograft migration, and aneurysm remodeling were secondary endpoints. Results: Mean follow-up was 16.3±12.6 months. One-year mortality was 6.6% (9.5% WA versus 6.2% CG); overall mortality was 14.3% (p=0.414). No aneurysm rupture occurred. At 1, 2, and 3 years, respectively, cumulative reinterventions (20%/20%/20% WA versus 12%/15%/20% CG; p=0.633) and endoleak rates (25%/25%/25% WA versus 17%/22%/34% CG; p=0.649) were comparable. In both groups, most completion endoleaks resolved (42.9% WA versus 74.4% CG; p=0.474), but few de novo endoleaks did (0% WA versus 12.8% CG; p=0.538). Anticoagulation did not affect mean time to aneurysm sac shrinkage (1.3±0.3 WA versus 1.4±0.1 years CG; p=0.769). Conclusions: After EVAR, anticoagulation appears safe and does not significantly alter mortality, risk for rupture, or the incidence of reintervention. Early endoleaks appear more common in anticoagulated patients, but anticoagulation does not preclude spontaneous endoleak resolution nor does it increase late endoleak rates. Irrespective of the anticoagulation status, early but not late endoleaks usually sealed spontaneously. Observing type II endoleaks appears safe in the absence of aneurysm enlargement.