Coronary artery spasm-induced acute myocardial infarction in patients with myocardial infarction with non-obstructive coronary arteries.

Coronary artery spasm-induced acute myocardial infarction (CASIAMI) is one of the etiologies of myocardial infarction with non-obstructive coronary arteries (MINOCA). We retrospectively analyzed the incidence and clinical characteristics of Japanese patients with CASIAMI and non-obstructive coronary arteries. We experienced 62 patients with MINOCA (10 thrombosis, 7 unknown causes, and 45 CASIAMI) among 991 patients with suspected AMI. Pharmacological spasm provocation testing was performed in 37 patients. CASIAMI without obstructive coronary arteries was found in 4.5% of patients with suspected AMI and was observed in 73% of patients with MINOCA. Patients with CASIAMI were frequently males and had relatively small AMIs. Spontaneous spasm was recognized in 8 patients. We could reproduce provoked spasm in 37 patients with MINOCA, including 23 patients with multiple spasm. No patients died during the follow-up period. The clinical outcomes in patients with CASIAMI under optimal coronary vasodilators were satisfactory.