Trial of combined warfarin plus dipyridamole or aspirin therapy in prosthetic heart valve replacement: Danger of aspirin compared with dipyridamole

James H. Chesebro, Valentin Fuster, Lila R. Elveback, Dwight C. McGoon, James R. Pluth, Francisco J. Puga, Robert B. Wallace, Gordon K. Danielson, Thomas A. Orszulak, Jeffrey M. Piehler, Hartzell V. Schaff

Research output: Contribution to journalArticlepeer-review

213 Scopus citations

Abstract

Despite the use of oral anticoagulation in patients with prosthetic heart valves, persistent thromboembolism over time warrants a search for improved methods of prevention. Thus, patients receiving 1 or more mechanical prosthetic heart valves were randomized to therapy with warfarin plus dipyridamole (400 mg/day) or warfarin plus aspirin (500 mg/day) on the basis of location and type of valve and surgeon, and followed up with a concurrent, nonrandomized control group taking warfarin alone. In 534 patients followed up 1,319 patient-years, excessive bleeding (necessitating blood transfusion or hospitalization) was noted in the warfarin plus aspirin group (23 of 170 [14%], or 6.0 100 patient-years) compared with warfarin plus dipyridamole (7 of 181 [4%], or 1.6 100 patient-years, p <0.001), or warfarin alone (9 of 183 [5%], or 1.8 100 patient-years, p <0.001). A trend was evident toward a reduction in thromboembolism in the warfarin plus dipyridamole group (2 of 181 [1%], or 0.5 100 patient-years) as compared with warfarin plus aspirin (7 of 170 [4%], or 1.8 100 patient-years), or warfarin alone (6 of 183 [4%], or 1.2 100 patient-years). Adequacy of anticoagulation (based on 12,720 prothrombin time determinations) was similar in all 3 groups with 65% of prothrombin times in the therapeutic range (1.5 ≤prothrombin time/control ≤2.5), 30% too low, and 5% too high. Warfarin plus aspirin therapy resulted in excessive bleeding and is contraindicated. Longer follow-up study is needed to determine whether further separation of the incidence of thromboembolism can be detected.

Original languageEnglish (US)
Pages (from-to)1537-1541
Number of pages5
JournalThe American journal of cardiology
Volume51
Issue number9
DOIs
StatePublished - May 15 1983

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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