Objective Use of vitamin K antagonist (VKA) versus antiplatelet (AP)/no therapy following bioprosthetic valve implantation remains controversial. The aims of the current study were to (a) systematically review the published literature comparing the use of VKA versus AP/no treatment in such patients and (b) perform a meta-analysis of the risks and benefits of using a VKA compared with AP/no therapy.

Methods Five databases were searched including PubMed, Medline, Embase, Ovid and Cochrane for randomised clinical trials and observational studies comparing VKA (group I) versus AP/no therapy (group II). Outcome was after surgical intervention. Mantel-Haenszel odds ratio (OR) was calculated using random-effects meta-analysis for the outcome. Heterogeneity was assessed by I² statistics. A total of 14 studies were included (two randomised trials, 12 observational studies and one conference abstract, 31 740 patients).

Results Between groups I (VKA) and II (AP/no therapy), there were no differences in thromboembolic events (145 (1%) vs 262 (1.5%), OR 0.96 (95% CI 0.60 to 1.52)), all-cause mortality (351 (3.5%) vs 415 (2.9%), OR 1.48 (95% CI 0.87 to 2.50)) or need for redo surgery (47 (3.3%) vs 55 (3.2%); OR 0.81 (95% CI 0.42 to 1.58)). However, there were more bleeding events in group I versus group II (292 (2.6%) vs 189 (1.1%); OR 2.26 (95% CI 1.67 to 3.05)).

Conclusions In a meta-analysis of randomised and observational studies of VKA versus AP/no treatment in patients undergoing bioprosthetic valve implantation, there was no benefit of adding a VKA regarding thromboembolism or mortality. However, use of a VKA was associated with increased risk of major bleeding.