Clopidogrel Tailoring Beneficial in Acute Coronary Syndrome
Dosing by platelet reactivity may help carriers of a particular polymorphism
THURSDAY, Aug. 12 (HealthDay News) -- Tailoring clopidogrel loading dose by platelet reactivity monitoring may overcome high on-treatment platelet reactivity (HTPR) in cytochrome (CYP) 2C19 2* carriers; this intervention may reduce risk of thrombosis after percutaneous coronary intervention (PCI), according to research published online Aug. 11 in the Journal of the American College of Cardiology.
Laurent Bonello, M.D., of the Université de la méditerranée in Marseille, France, and colleagues measured platelet reactivity and determined the presence of CYP 2C19 2* in 411 non-ST-segment elevation acute coronary syndrome patients. Their aim was to determine the impact of administering a clopidogrel loading dose tailored to platelet reactivity in this patient population undergoing PCI.
The researchers found at least one 2C19 2* allele in 134 patients (35.3 percent) for whom the mean vasodilator-stimulated phosphoprotein (VASP) index -- a measurement of platelet activity -- was significantly higher than in those patients homozygous for wild-type alleles. Out of the 134 2C19 2* allele-carrying patients, 103 had HTPR; their mean VASP decreased significantly after a second clopidogrel loading dose. Furthermore, dose adjustment tailored to platelet reactivity allowed 88 percent of the 2C19 2* patients with HTPR to overcome HTPR by reaching a VASP index under 50 percent.
"Increased and tailored clopidogrel loading dose according to platelet reactivity monitoring overcome HTPR in carriers of the loss-of-function CYP 2C19 2* polymorphism," the authors write.