Standard versus high loading doses of clopidogrel in Asian ST-segment elevation myocardial infarction patients undergoing percutaneous coronary intervention: insights from the Korea Acute Myocardial Infarction Registry.

Background: The optimal loading dose of clopidogrel in Asian patients with ST-segment elevation myocardial infarction (STEMI) has not been fully investigated. We compared bleeding, vascular complications, and midterm outcomes of a 300-mg versus a 600-mg loading dose of clopidogrel in a large series of Korean patients with STEMI undergoing primary percutaneous coronary intervention (PCI).

Methods: A total of 2,664 STEMI patients (age 61.96 ± 11.91 years, men 70.4%) who underwent primary PCI were enrolled in this study. The patients were divided into a standard loading dose group (300 mg; n = 1,447 patients) and a high loading dose group (600 mg; n = 1,217 patients). Bleeding and vascular complications, and in-hospital and clinical outcomes up to 12 months were compared between the 2 groups.

Results: In-hospital bleeding and vascular complications were similar between the 2 groups. There were no differences in bleeding and vascular complications and in 1- and 12-month clinical outcomes, including mortality, myocardial infarction, repeated PCI, and major adverse cardiac events, between the 2 groups. These findings were consistent even after the propensity score-matched analysis.

Conclusions: The standard loading dose of clopidogrel may be as safe and similarly effective as the high loading dose in Asian STEMI patients undergoing primary PCI.