Elevated Platelet Microparticles in Stable Coronary Artery Disease Are Unrelated to Disease Severity or to Indices of Inflammation

Platelet microparticles (PMPs), procoagulant membrane vesicles derived from activated platelets, are elevated in acute myocardial infarction and unstable angina but their relationship to inflammation and indices of coronary artery disease are unclear. We therefore hypothesised that PMPs are related to scores of coronary atheroma and/or coronary stenosis. Our study was completed by comparing PMP data with other platelet markers and with hs-CRP, marking inflammation. We recruited 54 patients attending for coronary angiography, comparing them to 35 age- and sex-matched controls. Peripheral blood was analysed for PMPs, percent platelets positive for CD62P and CD63 (all flow cytometry), soluble P selectin and hsCRP (both immunoassay). Patients exhibited higher PMPs, increased platelet %CD62P, %CD63 and soluble P selectin (all P < 0.01) and hs-CRP (P = 0.0167) than healthy controls. However, analysing only patients with an unequivocal classification, there were no significant (P </= 0.01) correlations with coronary atheroma or coronary stenosis. These findings provide no support for the hypothesis that PMPs are related to the degree of coronary artery disease and therefore may simply be a marker of widespread inappropriate platelet activity.