Prospective partially randomized comparison of clopidogrel loading versus maintenance dosing to prevent periprocedural myocardial infarction after stenting for stable angina pectoris

What is known and objective: Pre-treatment of clopidogrel 600 mg is better than 300 mg loading for reducing periprocedural myocardial infarction (PMI). We aimed to evaluate pre-treatment methods for preventing PMI among patients undergoing conventional coronary angiography (CAG) for stable angina pectoris. Materials and methods: The study analyzed 402 patients who underwent percutaneous coronary intervention (PCI) during 2010 – 2011 at three Korean hospitals. Clopidogrel-naïve patients received routine maintenance therapy (75 mg/day for ≥ 5 days) and were randomly assigned to a 300-mg reload (RL) or only the maintenance dose (MD). Patients who received a loading dose (LD; 600 mg at 2 – 24 hours before the procedure) were entered into a non-randomized group. Results: After excluding patients who showed an abnormal creatinine kinase myocardial band (CK-MB) level, the study included 233 patients in the LD group, 85 patients in the RL group and 84 patients in the MD group. The LD group had a significantly higher rate of PMI (LD: 21, RL: 3, MD: 0 cases; p = 0.007) and a significant increase in the mean CK-MB levels after 8 hours (p = 0.016) and 24 h (p = 0.01). However, there was no difference in PMI between the RL and MD groups. Furthermore, no significant differences between the three groups were observed in the P2Y12 reaction unit (PRU) values (p = 0.57). Albeit not significantly, the LD group had a higher rate of moderate-to-severe GUSTO bleeding within 7 days. What is new and conclusion: Clopidogrel maintenance is better than 600-mg loading for preventing PMI, and the RL protocol did not further prevent PMI.