Warfarin plus Aspirin After Aortic Valve Prosthesis Placement?

An observational study suggests that the combination reduces mortality, at the cost of increased bleeding, when used in the 3 months after surgery.

Patients receiving an aortic bioprosthesis have a low overall risk for thromboembolism, but controversy surrounds whether they benefit from anticoagulation in the first months after surgery. To address this issue, researchers used the Society of Thoracic Surgeons Adult Cardiac Surgery Database to compare the effectiveness of the early use of aspirin alone, aspirin plus warfarin, and warfarin alone.

The sample included 25,656 patients aged 65 (median age, 77; 39% women) who received an isolated aortic valve prosthesis at 797 hospitals from 2004 through 2006. At 3 months, the mortality rate was 3.0% in the aspirin-only group, 3.1% in the aspirin-plus-warfarin group, and 4.0% in the warfarin-only group. In the multivariable analysis, the addition of warfarin to aspirin was associated with a 20% relative reduction in risk for death (0.6% absolute risk reduction). Mortality with warfarin alone was no different than with aspirin alone. The addition of warfarin to aspirin was associated with 48% relative reduction in the risk for embolic events (0.4% absolute risk reduction). Again, warfarin alone was not associated with a reduction. Bleeding was more common in patients treated with warfarin plus aspirin than in those treated with aspirin only or warfarin only (2.8% vs. 1.0% and 1.4%, respectively).

Comment: Absolute risks for death and embolic events are low in the 3 months after the placement of an aortic valve bioprosthesis, but the addition of warfarin to aspirin provided additional risk reduction in this observational study, at the cost of more bleeding. The authors recommend warfarin plus aspirin for those at low risk for bleeding, and I agree — we ought to be personalizing treatment based on the bleeding risk.

Source: Journal Watch Cardiology

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