Thrombotic profile of East Asian and Western ACS patients and relationship to cardiovascular outcomes

Abstract

Abstract Background East Asian patients compared to Westerners, have a lower risk of ischemic heart disease and a higher risk of bleeding with antithrombotic medications. The underlying mechanisms are incompletely understood. Genetic differences may underlie lower coagulant and inflammation levels in EA compared to W populations. Objectives We sought to compare thrombotic profiles of East Asian and Western patients with myocardial infarction (MI) and relate these to cardiovascular outcomes. Methods In a 2 centre, prospective, observational study in the U.K. and Korea, blood samples from patients (n=515) with ST- or non-ST-elevation MI (STEMI and NSTEMI) were assessed using the Global Thrombosis Test, measuring thrombotic occlusion (OT) and endogenous fibrinolysis (LT) times. In STEMI patients, blood samples were taken immediately upon arrival, whilst in NSTEMI patients, blood samples were taken after DAPT loading. Patients were followed for 1 year for major adverse cardiovascular events and major bleeding. Results Major adverse cardiovascular events occurred significantly more frequently in Western than in East Asian patients (6.27% vs. 1.92%, p=0.014), driven by a higher rate of cardiovascular death (3.53% vs. 0.38%, p=0.01), with minimal major bleeding events (0.39% vs. 0.38%, p=1.0). East Asian patients showed reduced platelet reactivity (longer OT) compared to Western patients (646s [470-818] vs. 436s [320-580], p<0.001), with similar LT. In STEMI, OT (588s [440-759] vs. 361s [274-462], p<0.001) and LT (1854s [1389-2729] vs. 1338s [1104-1788], p<0.001) were longer in East Asian patients than Westerners. In NSTEMI, OT was longer (OT 734s [541-866] vs. 580s [474-712], p<0.001) and LT shorter (1519s [1058-2508] vs. 1898s [1614-2806], p=0.004) in East Asian than Western patients. While OT was unrelated, LT was a strong independent predictor of MACE after adjustment for risk factors (HR 3.70, 95% CI 1.43-9.57, p=0.007), predominantly in Western patients, and more so in STEMI than NSTEMI. Conclusion East Asian patients exhibit different global thrombotic profiles to Westerners, associated with a lower rate of cardiovascular events. The lower platelet reactivity in East Asian STEMI patients, even before antiplatelet therapy, may explain contribute to the lower risk of subsequent adverse ischaemic events.