Randomized trial of high loading dose of clopidogrel for reduction of periprocedural myocardial infarction in patients undergoing coronary intervention - Results from the ARMYDA-2 (Antiplatelet therapy for reduction of MYocardial Damage during Angioplasty) study

Background - Aggressive platelet inhibition is crucial to reduce myocardial injury and early cardiac events after coronary intervention. Although observational data have suggested that pretreatment with a high loading dose of clopidogrel may be more effective than a conventional dose, this hypothesis has never been tested in a randomized trial. Methods and Results - A total of 255 patients scheduled to undergo percutaneous coronary intervention were randomized to a 600-mg ( n = 126) or 300- mg ( n = 129) loading regimen of clopidogrel given 4 to 8 hours before the procedure. Creatine kinase MB, troponin I, and myoglobin levels were measured at baseline and at 8 and 24 hours after intervention. The primary end point was the 30-day occurrence of death, myocardial infarction (MI), or target vessel revascularization. The primary end point occurred in 4% of patients in the high loading dose versus 12% of those in the conventional loading dose group ( P = 0.041) and was due entirely to periprocedural MI. Peak values of all markers were significantly lower in patients treated with the 600-mg regimen ( P <= 0.038). Safety end points were similar in the 2 arms. At multivariable analysis, the high loading regimen was associated with a 50% risk reduction of MI ( OR 0.48, 95% CI 0.15 to 0.97, P = 0.044). An incremental benefit was observed in patients randomized to the 600-mg dose who were receiving statins, with an 80% risk reduction. Conclusions - Pretreatment with a 600-mg loading dose of clopidogrel 4 to 8 hours before the procedure is safe and, as compared with the conventional 300- mg dose, significantly reduced periprocedural MI in patients undergoing percutaneous coronary intervention. These results may influence practice patterns with regard to antiplatelet therapy before percutaneous revascularization.