Platelet FcγRIIa expression in patients with stable coronary artery disease.

OBJECTIVES:FcɣRIIa amplifies platelet activation and greater expression increases platelet reactivity. In patients with myocardial infarction (MI), high platelet FcɣRIIa identifies patients with an approximately 4-fold greater risk of MI, stroke, and death. We compared platelet FcɣRIIa in 2 groups: (1) patients who had not had an MI in the previous year and were undergoing cardiac catheterization and percutaneous coronary intervention (PCI) labeled as stable coronary artery disease (CAD), and (2) previously obtained results in patients with MI (n = 197). METHODS:Patients undergoing cardiac catheterization and PCI were enrolled. FcɣRIIa expression was quantified with the use of flow cytometry. Comparisons were made with Mann-Whitney Rank Sum Test and Chi Squared analysis. Significance was defined as P less than .05. RESULTS:Compared to patients with MI, patients with stable CAD (n = 49) were older (70 ± 9 years vs 63 ± 12 years) and were more likely to have had prior MI (43% vs 23%), prior revascularization (62% vs 33%), diabetes (35% vs 24%), and hypertension (98% vs 66%). In patients with stable CAD, platelet FcɣRIIa was, on average, lower than that seen in patients with acute MI (9746 ± 4316 vs 11 479 ± 2405 molecules/platelet, P less than .001). Patients with stable CAD exhibited a range of platelet FcɣRIIa (~4500 to ~27 000 molecules/platelet) similar to that seen in acute MI patients (~6500 to ~30 000 molecules/platelet). CONCLUSIONS:Compared to patients with MI, patients with stable CAD had, on average, lower platelet FcɣRIIa. However, the range of platelet FcɣRIIa was similar to that seen in patients with MI. These results support future studies designed to assess the prognostic implications of platelet FcɣRIIa in patients with stable CAD.