Lack of efficacy of clopidogrel pre-treatment in the prevention of myocardial damage after elective stent implantation

OBJECTIVES: The object of this study was to determine the effect of pre-treatment with clopidogrel in patients undergoing elective stent implantation. BACKGROUND: The treatment of patients with adenosine diphosphate receptor blockers after percutaneous coronary intervention (PCI) with stent implantation has been shown to decrease the incidence of subacute stent thrombosis. Furthermore, non-randomized studies on pre-treatment with clopidogrel among patients undergoing stent implantation have suggested a reduction in myocardial damage and clinical events. The effect of pre-treatment with clopidogrel has been studied in only a few randomized trials. METHODS: In a randomized trial, three days of pre-treatment with clopidogrel was compared with standard post-procedural treatment in 203 patients undergoing elective stent implantation. The primary end point was a rise in troponin I or creatine kinase-MB fraction (CK-MB) serum levels at 6 to 8 and 16 to 24 h after PCI. Secondary end points were death, stroke, myocardial infarction, coronary bypass grafting, repeated PCI, and subacute stent thrombosis at one and six months after PCI. RESULTS: No difference was found between non-pre-treated and pre-treated patients in the post-procedural elevation of troponin I (42 [43.3%] vs. 48 [51.1%], respectively, p = 0.31) or CK-MB (6 [6.3%] vs. 7 [7.4%], respectively, p = 0.78). Adjustment for possible confounding factors did not change these findings. Patient follow-up at one and six months showed no significant difference between the treatment groups in death, stroke, myocardial infarction, coronary artery bypass grafting, repeated PCI, or subacute stent thrombosis. CONCLUSIONS: In this randomized study, no beneficial effect of pre-treatment with clopidogrel on post-procedural elevation of troponin I and CK-MB or on clinical events after one and sixth months could be demonstrated. The study suggests that among patients with stable coronary syndromes in whom coronary stent implantation is planned, pre-treatment may not be beneficial in reducing early myocardial damage.