Benefit of statin therapy in patients with coronary spasm-induced acute myocardial infarction

Background: Coronary artery spasm is associated with vascular smooth muscle hyper-reactivity. Statins suppress coronary spasm by inhibiting the vascular smooth muscle contraction. However, it is unclear whether statin therapy benefits patients with coronary spasm-induced acute myocardial infarction (AMI).

Methods and results: We analyzed 501 (median age 57 years; male/female, 346/155) patients with coronary spasm-induced AMI with nonobstructive coronary arteries (stenosis severity <50%) from the Korea AMI Registry between November 2005 and October 2013. They were divided into two groups according to statin prescription at discharge (statin group n=292; nonstatin group n=209). The primary endpoint was the composite of 12-month major adverse cardiac events, including all causes of death, non-fatal myocardial infarction, and target vessel revascularization. The primary endpoint occurred in 17 patients during 12 months of follow-up. Statin therapy significantly reduced the risk of the composite primary endpoint [adjusted hazard ratio (HR): 0.30; 95% confidence interval (CI): 0.09-0.97; p=0.045]. Statin therapy reduced the risk of myocardial infarction (HR: 0.19; 95% CI: 0.04-0.93; p=0.040). However, we found no significant difference in the risk of the composite of all-cause death.

Conclusion: Statin therapy in patients with coronary spasm-induced AMI with nonobstructive coronary arteries was associated with improved clinical outcome, which was predominantly accounted for by reducing the incidence of myocardial infarction.