Comparison of Two-Year Outcomes of Acute Myocardial Infarction Caused by Coronary Artery Spasm Versus that Caused by Coronary Atherosclerosis

The study compared the 2-year outcomes of patients diagnosed with acute myocardial infarction (AMI) triggered by coronary artery atherosclerosis and AMI caused by coronary artery spasm. A total of 36,797 patients in the Korea AMI Registry were grouped into 2 categories—(1) AMI due to coronary artery spasm without stenotic lesion (CAS-AMI, n = 484); and (2) AMI induced by coronary artery atherosclerosis (CAA-AMI, n = 36,313). The major clinical outcomes of the 2 groups were compared over a 2-year clinical follow-up period. Major adverse cardiac events (MACE) were defined as the composite of total death, nonfatal myocardial infarction, and repeat revascularization. The incidence of MACE (7.1% vs 11.1%; p = 0.007) and repeat revascularization (0.4% vs 4.2%; p <0.001) in the CAS-AMI group were significantly lower than in the CAA-AMI group at 2 years. However, the incidence of total death and nonfatal myocardial infarction was similar in both the groups. Aborted cardiac arrest was strongly associated with 2-year mortality in the CAS-AMI group (hazard ratios 13.5, 95% confidence interval 5.34 to 34.15, p <0.001) The incidence of MACE in CAS-AMI patients was significantly lower than in the CAA-AMI group of patients up to 2 years due to the relatively lower rate of repeat revascularization in CAS-AMI patients. However, the incidence of total death or nonfatal myocardial infarction in CAS-AMI patients was not different from that of patients with CAA-AMI.