Frequency of prosthetic valve-related complications with very low level warfarin anticoagulation combined with dipyridamole after valve replacement using St. Jude Medical prostheses.

The safety of a very low level of anticoagulation combined with dipyridamole in a rheumatic population (mean age 31 +/- 13 years) with the St. Jude Medical (SJM) prosthesis has not yet been tested. Furthermore, no data are available on the safety of relatively infrequent monitoring of anticoagulation levels and of the necessity for different therapeutic targets according to valve position, number of risk factors, and other baseline risk factors for thromboembolism. In this study, the performance of the SJM prosthesis was tested using a target international normalized ratio (INR) of 2.0 to 2.5 combined with dipyridamole 300 mg/day applied uniformly to all patients. Clinical, biochemical, and echocardiographic data were acquired prospectively in 200 consecutive patients at 3-month intervals. Follow-up (mean 27 +/- 13 months) was complete in 95% of patients. Thirteen patients died (2.9%/patient year). Severe left ventricular dysfunction was the cause of death in 10 of 13 patients. Probability of survival (Kaplan-Meier) was 0.92 at 36 months and of event-free survival 0.84 at 36 months. The median INR was 2.0 +/- 0.9. Valve obstruction did not occur, and there were 3 thromboembolic events (0.6%/patient year). Incidence of bleeding was 1.6%/patient year (n = 7) and was major (hemorrhagic stroke) in 1 (0.2%/patient year). Thus, the SJM prosthesis performs very well despite the use of very low level warfarin anticoagulation combined with dipyridamole. A 3-month assessment of the anticoagulation level is safe. Left ventricular dysfunction rather than valve-related complications is the leading cause of mortality in this population.