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Evidence summaries

Antiplatelet and Anticoagulation for Patients with Prosthetic Heart Valves

Adding antiplatelet therapy, either dipyridamole or low-dose aspirin, to oral anticoagulation are effective in decreasing the risk of systemic embolism or death among patients with prosthetic heart valves. The risk of major bleeding is increased with antiplatelet therapy. Level of evidence: "A"

A Cochrane review [Abstract] 1 included 13 studies with a total of 4 122 patients. Compared with anticoagulation alone, the addition of an antiplatelet agent reduced the risk of thromboembolic events (OR 0.43, 95% CI 0.32 to 0.59) and total mortality (OR 0.57, 95% CI 0.42 to 0.78). Aspirin and dipyridamole reduced these events similarly. The risk of major bleeding was increased when antiplatelet agents were added to oral anticoagulants (OR 1.58, 95% CI 1.14 to 2.18).

For major bleeding, there was no evidence of heterogeneity between aspirin and dipyridamole and in the comparison of trials performed before and after 1990, around the time when anticoagulation standardisation with the international normalised ratio was being implemented. A lower daily dose of aspirin (< 100 mg) may be associated with a lower major bleeding risk than higher doses.

    References

    • Massel DR, Little SH. Antiplatelet and anticoagulation for patients with prosthetic heart valves. Cochrane Database Syst Rev 2013;(7):CD003464. [PubMed]

Primary/Secondary Keywords