Indices of platelet activation and the stability of coronary artery disease

Aim: To determine whether indices of platelet activation are associated with the stability of coronary artery disease (CAD). Methods: Platelet function was examined in 677 consecutive aspirin‐treated patients presenting for cardiac catheterization. Patients were grouped into recent myocardial infarction (MI), no MI but angiographically documented CAD (non‐MI CAD) and no angiographically detectible CAD (no CAD), as well as additional subgroups. Results: Compared with non‐MI CAD or no CAD patients, more patients with recent MI had a shortened platelet function analyzer (PFA)‐100 collagen‐epinephrine closure time (CT) and increased circulating monocyte‐platelet aggregates, neutrophil‐platelet aggregates, activated platelet surface GPIIb‐IIIa and plasma soluble CD40 ligand (sCD40L). More patients with non‐MI CAD had shortened PFA‐100 CTs and increased monocyte‐platelet aggregates compared with patients with no CAD. Platelet surface P‐selectin did not differ among the groups. Subgroup analysis revealed that decreasing PFA‐100 CT correlated with the stability of CAD. Conclusions: Indices of platelet activation, especially the PFA‐100 CT, are associated with the stability of CAD, and may reflect plaque instability, an ongoing thrombotic state and/or reduced responsiveness to aspirin.