New Antiplatelet agents and bedside platelet function testing

The authors review the rationale for platelet function testing and its application in monitoring patients on antiplatelet therapy. They also review recent clinical trials of newer antiplatelet agents. On the basis of this review, they reach conclusions on the current role of antiplatelet function testing in monitoring modern antiplatelet therapy and the role of the new antiplatelet agents in the treatment of ACS. Recent clinical trials have indicated that newer antiplatelet agents have advantages over clopidogrel in the treatment of ACS. Platelet function testing gives us a guide to the timing, efficacy, and variability of therapy and can correlate with poor patient outcomes; however, the use of antiplatelet function testing to tailor therapy does not seem appropriate.

Methods

• The authors reviewed recent publications on platelet function testing and clinical trials of newer antiplatelet therapies compared with clopidogrel.

Results

• Platelet function testing is complex, but there is now a bedside test, VerifyNow.
• High platelet reactivity has been associated with worse cardiovascular outcomes in patients undergoing percutaneous coronary intervention.
• Recent clinical trials have not found any advantage in outcomes in patients who have their therapy adjusted by monitoring their platelet function.
• Newer agents, prasugrel, ticagrelor, and cangrelor, produce more rapid, complete, less variable effects on platelet function than clopidogrel.
• Prasugrel was found to improve outcomes compared with clopidogrel in patients with ACS undergoing percutaneous intervention.
• Ticagrelor is beneficial in all patients with ACS and reduces cardiovascular mortality compared with clopidogrel.
• Cangrelor improves outcomes in patients undergoing stenting.
• Recent studies to assess the role of platelet function monitoring of the effects of clopidogrel and modifying treatments have not been successful.