Combined warfarin and antiplatelet therapy after St. Jude Medical valve replacement for mitral valve disease.

OBJECTIVES

The clinical effect of combined warfarin and antiplatelet therapy on the incidence of stroke and postoperative complications after mitral (plus aortic) valve replacement was studied and compared with that observed with warfarin therapy alone.

BACKGROUND

It has been reported that combined warfarin and antiplatelet therapy may be effective but may be associated with an increased hemorrhagic risk. Therefore, definite benefits of the treatment in patients with an implanted prosthetic valve have not been clearly documented.

METHODS

Between January 1980 and December 1992, 195 patients with a St. Jude Medical valve at the mitral (plus aortic) position were assigned to receive treatment with either warfarin alone (125 patients) or warfarin plus antiplatelet agents (70 patients), such as dipyridamole (150 or 300 mg daily, 14 patients) or ticlopidine (200 or 400 mg daily, 56 patients). A minimal dose of aspirin (10 to 40 mg) was added (29 patients) if the maximal platelet aggregation rate by collagen was not reduced. The target thrombotest level was 10% to 20%.

RESULTS

The two treatment groups were similar with regard to gender and age distribution. The number of patients with atrial fibrillation, left atrial thrombus, history of previous stroke, simultaneous aortic valve operation and previously performed valve procedures were comparable in the two groups. Actuarial survival rate at 10 years was 98.3 +/- 1.7% (mean +/- SD) in the warfarin plus antiplatelet group and 90.3 +/- 3.2% in the warfarin group (p < 0.05 at 1 and 9 to 12 years). The actuarial stroke-free rate at 10 years was 95.3 +/- 3.4% and 84.3 +/- 3.8%, respectively (p < 0.05 by the generalized Wilcoxon test). The actuarial complication-free rate at 10 years was 89.4 +/- 4.3% and 67.9 +/- 4.8%, respectively (p < 0.05 by the generalized Wilcoxon test). No hemorrhagic complications were seen in the warfarin plus antiplatelet group.

CONCLUSIONS

The results strongly indicate the effectiveness and safety of combined warfarin plus antiplatelet treatment after St. Jude Medical valve replacement for mitral (plus aortic) valve disease.