Clinical Characteristics Associated With High On-Treatment Platelet Reactivity Of Patients Undergoing Pci After A 300 Mg Loading Dose Of Clopidogrel, Measured By Thrombelastography

Background Dual antiplatelet therapy with clopidogrel and aspirin is the standard of care for patients undergoing percutaneous coronary intervention (PCI).Objective To determine the clinical characteristics associated with high on-treatment platelet reactivity (HPR) of patients undergoing PCI after a 300 mg loading dose of clopidogrel, measured by thrombelastography (TEG).Methods and results 394 consecutive patients were enrolled in this prospective observational study. All had been receiving aspirin 100 mg/day for more than 7 days, but were clopidogrel naive. A 300 mg loading dose of clopidogrel was given more than 12 h before the procedure. The cut-off point for HPR was defined as = 70% adenosine-5-diphosphate-induced aggregation. The prevalence of HPR was 21% as measured by TEG. More women than men (41.7% vs 27.1%, p= 0.01) were found in the HPR group. Raised glycosylated haemoglobin (HbA1c) was more prevalent in the HPR group than in the group with normal on-treatment platelet reactivity (NPR) (45.2% vs 30.0%, p= 0.009). Patients with HPR had a higher level of total plasma cholesterol (4.8 +/- 1.5 mmol/l vs 4.3 +/- 1.1 mmol/l, p= 0.002) and low-density lipoprotein cholesterol (2.8 +/- 1.1 mmol/l vs 2.5 +/- 0.9 mmol/l, p= 0.022) than those with NPR. Multivariable logistic regression analysis showed that female gender (OR= 3.175, 95% CI 1.428 to 7.059, p= 0.005) and raised HbA1c (OR= 1.911, 95% CI 1.066 to 3.428, p= 0.03) independently predicted the occurrence of HPR.Conclusions Despite pretreatment with aspirin and a 300 mg loading dose of clopidogrel, 21% patients undergoing PCI exhibited HPR measured by TEG. A raised level of HbA1c and female gender independently predicted the findings.