Objective: To evaluate effect of duration of clopidogrel use on clinical follow-up outcomes in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention.
Methods: A total of 214 patients with acute myocardial infarction undergoing primary percutaneous coronary intervention between January 2005 to December 2007 were enrolled. All patients were divided into two groups by duration of clopidogrel use: <1 year group (n=59) and > or =1 years group (n=155). Baseline characteristics [age, gender, angiographic characteristics, Killip classification, LVEF (left ventricular ejection fraction) , CK (creatine kinase), CK-MB, CTnI (cardiac troponin-I), hemoglobin levels and history of hypertension, diabetes, hyperlipidemia, obesity and smoking] of two groups were collected. Clinical follow-up end-point was major adverse cardiac event (MACE) including death, acute myocardial infarction, stent thrombosis and stent restenosis. Clinical follow-up duration was 41.6 +/- 16.3 months. MACE occurred in 28 patients.
Results: Rates of male, infarction site, infarction relative artery, multivessel disease, Killip classification (class I), aspirin use and history of smoking, obesity, hypertension and hyperlipidemia were not different (P > 0.05) in duration of clopidogrel use <1 year group and > or =1 years group. Average LVEF, hemoglobin levels and rate of drug-eluting stents were significantly lower in duration of clopidogrel use <1 year group than that in duration of clopidogrel use > or =1 years group (P < 0.0001, P < 0.0001, P = 0.0065). Average CK, CK-MB, CTnI were significantly higher in duration of clopidogrel use > or =1 years group than that in duration of clopidogrel use <1 year group (P < 0.0001). Rate of diabetes and average age were significantly higher in duration of clopidogrel use <1 year group than that in duration of clopidogrel use > or =1 years group (P = 0.0190, P < 0.0001). Incidence of MACE in follow-up period was significantly lower in duration of clopidogrel use > or =1 years group than that in duration of clopidogrel use < 1 year group (6.45% vs. 30.51%, P < 0.01). After stopping clopidogrel use, incidence of MACE in followup period was significantly lower in duration of clopidogrel use > or =1 years group than that in duration of clopidogrel use <1 year group (2.58% vs. 20. 34%, P < 0.01).
Conclusion: Primary percutaneous coronary intervention is an effective therapeutic method. Incidence of MACE in follow-up period was significantly lower in duration of clopidogrel use > or =1 years group than that in duration of clopidogrel use <1 year group. Duration of clopidogrel use may influence clinical outcomes in follow-up period in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention.