Assessment of oral antithrombotic therapy by platelet function testing

Dual antiplatelet therapy with clopidogrel and aspirin is recommended for the prevention of ischemic events in high-risk patients with coronary artery disease. In patients with atrial fibrillation, oral anticoagulant therapy with warfarin is the 'gold standard' for the prevention of thromboembolism. Nearly 20% of patients with atrial fibrillation also have coronary artery disease and receive combination therapy consisting of dual antiplatelet therapy plus warfarin, also known as triple antithrombotic therapy. Unfortunately, though, increased bleeding risk is a major concern during triple therapy. Whether platelet function testing can guide personalized antiplatelet therapy and reduce ischemic risk is under investigation in large trials of patients treated with coronary artery stents. However, limited data are available to establish the relationship between platelet function testing and bleeding in patients treated with dual or triple therapy. Personalized treatment strategies could help to achieve maximum clinical benefit while avoiding excessive bleeding complications. In this article, we review available data on the utility of platelet function testing in assessing bleeding risk and its potential role in personalizing combination antithrombotic therapies with the aim of reducing ischemic events and the frequency of bleeding.