Acute myocardial infarction in Taiwanese with angiographically normal coronary arteries: Role of coronary artery spasm

Background: Acute myocardial infarction (AMI) with angiographically normal coronary arteries is not an uncommon event. However, data is lacking on the risk factors and prognosis for Taiwanese patients with AMI and normal coronary arteries. Methods: From June 1998 to December 2000, coronary angiography was performed in 191 consecutive patients with AMI. Intracoronary ergonovine administration test was performed in these patients when normal coronary arteries were identified. Coronary artery spasm was defined as a diameter reduction of over 70% concurrent with chest pain and ischemic ST-segment changes. Results: A total of 19 (10%) patients with AMI and normal coronary arteries were identified. They comprised 14 males and 5 females with a mean age of 61 ± 6 years. Data were available for a median follow-up period of 2 years after the AMI. The anterior wall was the most common location of infarction, occurring in 10 in 19 (53%) of these patients. All but 1 (95%) of the infarct-related coronary arteries in these patients were spastic. The most common cardiac risk factor was smoking. One patient who had a history of amphetamine use suffered from recurrent angina attacks which usually occurred after amphetamine misuse. Only 1 of these 19 patients died (due to hepatocellular carcinoma) during the study period. Conclusions: AMI is not uncommon in Taiwanese patients with angiographically normal coronary arteries. Angiographic evaluation in Taiwanese patients recovering from AMI is warranted to identify those with normal coronary arteries. Intracoronary ergonovine test should be performed in patients and normal coronary arteries to unmask coronary artery spasm. The use of calcium channel blockers is indicated in patients with positive tests.