There is a recognized incidence of clopidogrel resistance in patients with a genetic predisposition: CYP2C19 “nonfunctioning alleles.”
In these patients, coronary events may continue despite adequate dosing with clopidogrel, at times with disastrous consequences, necessitating a means for monitoring antiplatelet therapy.
Diagnosis
P2Y12 Assay
Assay measures plt inhibition by plavix
Safe for Procedures+Surgery: <20%
P100 Assay
Measures plt inhibition due to ASA and plavix
References
Simon T, Verstuyft C, Mary-Krause M, et al. Genetic determinants of response to clopidogrel and cardiovascular events (French registry study). N Engl J Med 2009; 360:363-375
Collet J-P, Hulot JS, Pena A, et al. Cytochrome P-450 2C19 polymorphism in young patients treated with clopidogrel after myocardial infarction: a cohort study. Lancet 2009; 373:309-317
Mega JL, Close SL, Wiviott SD, et al. Cytochrome P-450 polymorphisms and response to clopidogrel. N Engl J Med 2009; 360:354-362
Simon T, Verstuyft C, Mary-Krause M, et al. Genetic determinants of response to clopidogrel and cardiovascular events (French registry study). N Engl J Med 2009; 360:363-375
Collet J-P, Hulot JS, Pena A, et al. Cytochrome P-450 2C19 polymorphism in young patients treated with clopidogrel after myocardial infarction: a cohort study. Lancet 2009; 373:309-317
