Aspirin and clopidogrel resistance using the cone and plate(let) analyser in Indian patients with coronary artery disease.

Background: Resistance to antiplatelet drugs is a well-known entity. However, data for aspirin and clopidogrel resistance, and its clinical significance, in Indian patients are meagre.

Aims And Objectives: We sought to determine the prevalence of resistance to aspirin and clopidogrel in Indian patients with stable coronary heart disease (CHD), using the cone and plate(let) analyser (CPA) technology.

Setting And Design: A single centre prospective study in a cohort of patients with stable CHD on chronic aspirin and clopidogrel therapy attending the cardiology outpatient clinic of a tertiary care hospital in Southern India.

Methods: Platelet function was measured using the Impact-R device (DiaMed, Cressier, Switzerland). Resistance to aspirin and clopidogrel was measured in a cohort of 100 patients with stable documented CHD. Relation of antiplatelet resistance to various clinical comorbidities was also assessed.

Results: Of the 100 patients, 85% were men, and 15% were above 65 years of age. 47% patients had diabetes, 29% of patients were hypertensive and 16% were smokers. Using the CPA, 12 patients (12%) were found to be resistant to aspirin and 19 patients (19%) were clopidogrel resistant. In addition, 10 patients (10%) were resistant to both aspirin and clopidogrel. There was no significant correlation between the presence of antiplatelet resistance and several baseline clinical variables, including age, sex, diabetes, hypertension and smoking.

Conclusions: Resistance to aspirin and clopidogrel and dual antiplatelet resistance are prevalent in Indian patients, comparable with the prevalence worldwide. The CPA is a feasible assay to determine antiplatelet resistance.