[Clinical features of coronary artery spasm patients with or without myocardial bridge].

OBJECTIVE: To investigate the clinical features of coronary artery spasm patients with or without myocardial bridge and explore the roles of endothelial dysfunction in these patients. METHODS: One hundred eighteen patients undergone acetylcholine provoking test were divided into myocardial bridge (MB) group (n = 26) and non-myocardial bridge (NMB) group (n = 92). The results of acetylcholine test, treadmill exercise electrocardiography, stress myocardial perfusion scintigraphy, plasma level of endothelin-1 and nitric oxide were compared between MB group and NMB group. RESULTS: Coronary artery spasm was induced in 21 patients in MB group (81%) and 52 patients in NMB group (57%, P < 0.05). Positive treadmill electrocardiography was obtained in 19 patients in MB group (73%) and 7 patients in NMB group (8%, P < 0.001). Ischemic perfusion defect in 20 (77%) and 9 patients (10%, P < 0.001) and reverse redistribution in 23 (88%) and 68 patients (74%, P > 0.05). Patients showed different clinical features in MB group and NMB group (more short-duration exertional angina and could not be readily released by nitroglycerine in MB group while more patients experienced long-lasting variant angina and symptoms could be readily released by nitroglycerine). Plasma endothelin-1 level was significantly higher [(132.1 +/- 6.5) ng/L vs. (108.5 +/- 8.2) ng/L, P < 0.01] while nitric oxide was significant lower [(84.7 +/- 17.5) ng/L vs. (99.8 +/- 18.2) ng/L, P < 0.05] in MB group compared to NMB group. CONCLUSION: MB patients were prone to coronary artery spasm partly due to endothelial dysfunction. Patients with MB and coronary artery spasm also showed classic clinical symptoms and positive stress tests for ischemia.