Clopidogrel resistance in North Indian patients of coronary artery disease and lack of its association with platelet ADP receptors P2Y1 and P2Y12 gene polymorphisms

Aspirin and Clopidogrel are used in prophylaxis of patients undergoing percutaneous coronary intervention and long-term prevention of cardiovascular and cerebrovascular events. Clopidogrel resistance has been attributed to P2Y1 and P2Y12 adenosine diphosphate (ADP) receptor polymorphisms. This study enrolled 100 patients of coronary artery disease (CAD) who were on the maintenance dose of clopidogrel (75 mg OD) with or without aspirin. In addition, 10 received loading dose (300 mg) prior to percutaneous coronary intervention. Relevant clinical and drug history were elicited. ADP-induced platelet aggregation study and PCR-RFLP for P2Y1 (1622A > G) and P2Y12 (i-T744C) polymorphisms were performed. Two groups of controls were used for defining cut-off for platelet aggregation response. Follow-up data, wherever available was recorded. The most common pattern of aggregation response was disaggregation, either complete (46.4%) or partial (53.6%). A frequency of 13% clopidogrel non-responders and 19% semi-respon...