[Prevalence of Clopidogrel resistance in patients candidate for percutaneous coronary intervention]

ABSTRACT

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 micro 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