Resistance to clopidogrel treatment in patients with coronary artery disease
clopidogrel ; resistance ; percutaneous coronary interventions ; antiplatelet agents ; coronary artery disease
Background: Clopidogrel reduces ischemic events rate in patients (pts) with coronary artery disease (CAD). In some pts inhibitory effect of clopidogrel is weakly expressed despite use of recommended loading dose (LD). Aim: To assess frequency and possibility of early identification of clopidogrel resistance. Methods: In 60 pts with CAD platelet aggregation inhibition (DPAI) was assessed at baseline and 3, 6, 12 as well as 24 h and 30 days after administration of clopidogrel LD (300 mg). Response to clopidogrel was calculated as absolute difference between the baseline DPAI and DPAI obtained at the investigated time-points (ΔDPAI). Results: After 24 h from clopidogrel LD 14 (23.33%) pts were identified as non-responders (ΔDPAI ≤10%). Demographic and clinical variables were similar in responders and non-responders. ΔDPAI assessed at 6 h correlated well with ΔDPAI at 24 h (r=0.75; p<0.001). No differences in the rate of ischemic or bleeding complications between groups were noted. Conclusions: Resistance to clopidogrel is frequent among CAD patients. There is no significant correlation between resistance to clopidogrel phenomenon and demographic characteristics, as well as concomitant pharmacological treatment. Early identification of pts resistant to clopidogrel is possible and may be used in everyday clinical practice.