Prevalence of Clopidogrel resistance in patients candidate for percutaneous coronary intervention

In patients who undergo coronary angioplasty, Clopidogrel resistance is accompanied with increased risk of cardiovascular events (unstable angina, recurrent MI, death, etc). In different studies resistance to Clopidogrel has been reported to be up to 30%. Identification of these patients and determining the contributing factors can help us to reduce cardiovascular events. This cross-sectional study was carried out on candidates of elective percutaneous coronary intervention (PCI) in Shahid Modarres Hospital. Resistance to Clopidogrel was evaluated by platelet aggregometry in platelet-rich-plasma (PRP) using a routine aggregometer (Helena Biosciences Europe). The platelet aggregation was measured before and after exposure to 20 µ mol ADP as a reagent. Contributing factors such as age, gender, metabolic factors and medications were examined by Chi-square test. This study was run on 90 candidates for elective PCI. Their mean age was 62.6±10.2 years and 52.2% were male. 20% were semi-responder and 7.8% was non-responder. Gender, hypertension, obesity, using angiotensin-converting enzyme inhibitors and calcium channel blockers did not have any role in Clopidogrel resistance, but diabetes, hyperlipidemia, using beta blockers and statins were more common in Clopidogrel resistant patients (p<0.005). ‍ Considering both non-responders and semi-responders, prevalence of resistance to Clopidogrel was 27.8%, so we must be worried about it. Further larger studies should be designed to determine and manage the contributing factors.