High platelet reactivity is associated with myocardial infarction in premenopausal women: a population-based case–control study

Summary Background: Platelets are involved in the occlusion of coronary arteries after rupture of an atherosclerotic plaque. Furthermore, activated platelets release large quantities of growth factors, chemokines and interleukines that regulate inflammatory reactions. Therefore, we hypothesized that high basal platelet reactivity may contribute to an increased risk of myocardial infarction (MI) in premenopausal women. Methods: We assessed the relation between high platelet reactivity and MI in a population-based case–control study among premenopausal women (aged < 50 years). We used multivariable logistic regression to quantify the effect of high platelet reactivity, adjusted for potential confounders. Platelet reactivity was estimated by plasma levels of neutrophil activating peptide 2 (NAP-2), CXC chemokine ligand (CXCL)4, soluble glycoprotein 1b (sGPIb) and soluble P-selectin. Results: High platelet reactivity (i.e. levels ≥ 90th percentile control subjects) was associated with a 2- to 3-fold increased incidence of MI: the adjusted odds ratios (ORs) were 3.0 [95% confidence interval (CI) 1.4–6.4] for NAP-2, 2.2 (0.9–5.1) for CXCL4, 1.9 (0.7–4.6) for sP-selectin and 2.5 (1.1–5.7) for sGPIb. The incidence of MI dose-dependently increased when more markers were elevated. High platelet reactivity according to both NAP-2 and sGPIb was associated with an up to tenfold increased incidence (9.9, 95% confidence interval 2.0–48.3). Conclusions: High basal platelet reactivity was associated with a 2- to 3-fold higher incidence of MI compared with normal platelet reactivity in premenopausal women. Our results suggest that high basal platelet reactivity may contribute to a higher risk of MI.