PAR4 variants are differentially susceptible to pharmacological inhibition. (A-C) Platelets from donors genotyped for rs773902 were washed, incubated with the indicated concentrations of vorapaxar (VPX) (A-B) or YD-3 (C), and then stimulated with (A) 5 μM PAR1-AP or (B-C) 100 μM PAR4-AP. Aggregation was measured using light transmission aggregometry. n = 3 each genotype. Horizontal lines indicate mean. P = .02.