Combined low-dose aspirin and warfarin anticoagulant therapy of postoperative atrial fibrillation following mechanical heart valve replacement.

Abstract

The safety and efficacy of combined low dose aspirin and warfarin therapy in patients with atrial fibrillation after mechanical heart valve replacement were evaluated. A total of 1016 patients (620 females, mean age of 36.8±7.7 years) admitted for cardiac valve replacement and complicated with atrial fibrillation after surgery were randomly divided into study (warfarin plus 75-100 mg aspirin) or control (warfarin only) groups. International normalized ratio (INR) and prothrombin time were maintained at 1.8-2.5 and 1.5-2.0 times the normal values, respectively. Thromboembolic events and major bleedings were registered during the follow-up period. Patients were followed up for 24±9 months. The average dose of warfarin in the study and control groups was 2.91±0.83 mg and 2.88±0.76 mg, respectively (P>0.05). The incidence of overall thromboembolic events in study group was lower than that in control group (2.16% vs. 4.35%, P=0.049). No statistically significant differences were found in hemorrhage events (3.53% vs. 3.95%, P=0.722) or mortality (0.20% vs. 0.40%, P=0.559) between the two groups. Combined low dose aspirin and warfarin therapy in the patients with atrial fibrillation following mechanical heart valve replacement significantly decreased thromboembolic events as compared with warfarin therapy alone. This combined treatment was not associated with an increase in the risk of major bleeding or mortality.