Background and purpose: Vasospastic angina (VSA) is characterized by the transient constriction of epicardial coronary arteries, leading to myocardial ischemia. Chest symptoms in patients with VSA typically occur at rest and also from midnight to early morning. However, we have occasionally experienced patients with VSA who have had chest symptoms even during exercise. However, factors contributing to the chest symptoms during exercise in patients with VSA remain unclear. Therefore, we investigated this relationship.
Methods: A total of 101 patients with VSA (mean age: 67 years, 51 men and 50 women) were investigated. VSA was defined as >90% narrowing of the epicardial coronary arteries (observed using angiography during a spasm provocation test with ergotamine maleate or acetylcholine), accompanied by the characteristic chest pain and/or ST segment deviation on electrocardiography. In each patient, detailed examination regarding the chest symptoms at rest (n=85), during exercise (n=2), and both at rest and during exercise (n=14) was performed. Patients were divided into the following two groups: group I consisted of patients with VSA whose chest symptoms occurred only at rest (n=85, 84%) and group II consisted of patients with VSA whose chest symptoms occurred during exercise (n=16, 16%). On a coronary angiography, the presence of atherosclerosis (% stenosis >25%), significant coronary stenosis (% stenosis >50%), and myocardial bridging (MB) defined as the narrowing of the epicardial coronary artery during systole were checked. Clinical parameters, including conventional coronary risk factors and angiographic findings, were assessed in the two groups.
Results: There were no significant differences in the conventional coronary risk factors between the two groups. The presence of atherosclerosis (group I: 58% vs. group II: 75%; NS) and significant coronary stenosis (group I: 10% vs. group II: 25%; NS) were different in the groups. The presence of MB was significantly higher in group II (9/16, 56%) than in group I (7/85, 8%, p<0.0001). The presence of MB was the only factor associated with group II.
Conclusions: These findings suggest that the presence of MB rather than coronary atherosclerosis or significant coronary stenosis may contribute to the chest symptoms during exercise in patients with VSA.