EVOLVING ROLE OF PLATELET FUNCTION TESTING IN ACUTE CORONARY SYNDROMES


Rakesh K. Sharma, M.D., University of Arkansas Medical Science, Little Rock, AR, USA

The substantial reduction in ischemic events provided by the dual anti-platelet regimen with aspirin and clopidogrel is extensively published in patients with acute coronary syndrome and patient’s undergoing percutaneous coronary intervention (PCI). Recently there have been several “boxed warning” on clopidogrel and its variable response which lead to intense controversy on pharmaokokinetic and pharmacodynamic and pharmacogenomic issues of anti- platelet drugs especially clopidogrel. Research use of platelet function testing has been successfully validated in identifying the new anti-platelet drugs like prasugrel and ticagrelor. These platelet function assays are not regarded as just a laboratory phenomenon anymore; rather a tool shown to predict mortality in several clinical trials. It is believed that sub optimal response to anti platelet regimen (pharmacodynamic effect) may be associated with cardiovascular, cerebrovascular and peripheral artery events. There has been intense controversy about this variable response of anti platelet drugs and role of platelet function testing to guide anti platelet therapy. While the importance of routine platelet functions testing may be uncertain, it may be useful in high risk patients such as diabetes mellitus, diffuse three vessels coronary artery disease, left main stenosis, diffuse atherosclerotic disease and chronic renal failure, undergoing PCI and in patient with suspected pharmacodynamic interaction with other drugs to assure the adequacy of platelet inhibition. While we wait for definitive trials, a predictive prognostic algorithm is necessary to individualize anti platelet therapy with P2Y12 inhibitors based on platelet function assays and genetic testing.