Platelet FcgRIIa as a Marker of Cardiovascular Risk After Myocardial Infarction

BACKGROUND A previous single-center study of patients with myocardial infarction (MI) showed that platelet FcgRIIa (pFCG) can distinguish patients at higher and lower risk of subsequent MI, stroke, and death. OBJECTIVES The authors performed an 800-patient 25-center study to validate the prognostic implications of pFCG. METHODS Patients with type 1 MI (ST-segment elevation and non-ST-segment elevation) were enrolled in a prospective noninterventional trial during their index hospitalization. Enrolled patients had at least 2 of the following characteristics: age >= 65 years, multivessel coronary artery disease, previous MI, chronic kidney disease, or diabetes mellitus. Flow cytometry was used to quantify pFCG at a core laboratory. A predefined threshold was used to identify high and low pFCG. Patients were queried every 6 months by telephone with a standardized questionnaire. Events were confirmed by review of medical records. RESULTS Treatment with antithrombotic therapy (aspirin, P2Y12 inhibitors, and anticoagulants) was similar in patients with high and low pFCG. The primary composite endpoint (MI, stroke, death) occurred more frequently in patients with high pFCG (HR: 2.09; 95% CI: 1.34-3.26; P = 0.001). Among individual components of the composite, both death (HR: 2.57; 95% CI: 1.50-4.40; P = 0.001) and MI (HR: 3.24; 95% CI: 1.64-6.37; P = 0.001) were more frequent in patients with high pFCG. CONCLUSIONS Quantifying pFCG identifies patients at higher and lower risk of subsequent cardiovascular events. This prognostic information will be useful in clinical decisions regarding the intensity and duration of antiplatelet therapy. (Assessment of Individual Risk of Cardiovascular Events by Platelet FcgRIIa; NCT05175261) (JACC. 2024;84:1721-1729) (c) 2024 by the American College of Cardiology Foundation.