Open AccessPlatelet reactivity in response to aspirin and ticagrelor in African-Americans and European-Americans
Author(s) -
Margaret Infeld,
Kevin A. Friede,
Tan Ru San,
Holly J. Knickerbocker,
Geoffrey S. Ginsburg,
Thomas L. Ortel,
Deepak Voora
Publication year - 2020
Publication title -
journal of thrombosis and thrombolysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.708
H-Index - 67
eISSN - 1573-742X
pISSN - 0929-5305
DOI - 10.1007/s11239-020-02327-w
Subject(s) - ticagrelor , aspirin , medicine , platelet , p2y12 , epinephrine , adenosine diphosphate , platelet activation , clopidogrel , platelet aggregation
Platelet gene polymorphisms are associated with variable on-treatment platelet reactivity and vary by race. Whether differences in platelet reactivity and aspirin or ticagrelor exist between African-American and European-Americans remains poorly understood. Biological samples from three prior prospective antiplatelet challenge studies at the Duke Clinical Research Unit were used to compare platelet reactivity between African-American and European-American subjects. Platelet reactivity at baseline, on-aspirin, on-ticagrelor, and the treatment effect of aspirin or ticagrelor were compared between groups using an adjusted mixed effects model. Compared with European-Americans (n = 282; 50% female; mean ± standard deviation age, 50 ± 16), African-Americans (n = 209; 67% female; age 48 ± 12) had lower baseline platelet reactivity with platelet function analyzer-100 (PFA-100) (p < 0.01) and with light transmission aggregometry (LTA) in response to arachidonic acid (AA), adenosine diphosphate (ADP), and epinephrine agonists (p < 0.05). African-Americans had lower platelet reactivity on aspirin in response to ADP, epinephrine, and collagen (p < 0.05) and on ticagrelor in response to AA, ADP, and collagen (p < 0.05). The treatment effect of aspirin was greater in European-Americans with an AA agonist (p = 0.002). Between-race differences with in vitro aspirin mirrored those seen in vivo. The treatment effect of ticagrelor was greater in European-Americans in response to ADP (p < 0.05) but with collagen, the treatment effect was greater for African-Americans (p < 0.05). Platelet reactivity was overall lower in African-Americans off-treatment, on aspirin, and on ticagrelor. European-Americans experienced greater platelet suppression on aspirin and on ticagrelor. The aspirin response difference in vivo and in vitro suggests a mechanism intrinsic to the platelet. Whether the absolute level of platelet reactivity or the degree of platelet suppression after treatment is more important for clinical outcomes is uncertain.