Characteristics of treadmill electrocardiography and dipyridamole 201Tl myocardial perfusion imaging in patients with coronary artery spasm

Objective: To investigate the characteristics of treadmill electrocardiography and dipyridamole 201Tl myocardial perfusion imaging in patients with coronary artery spasm, and to explore a non-invasive procedure for diagnosing coronary artery spasm. Methods: The patients who had chest pain but no significant coronary artery stenosis and were willing to undergo acetylcholine test were included. Treadmill electrocardiography, dipyridamole and rest 201Tl myocardial perfusion computed tomography were performed before or after coronary angiography. The relationship between the results of above mentioned stress tests and coronary spasm was investigated. Results: Acetylcholine test was performed on all the 52 patients and provoked coronary artery spasm in 42 patients of them. Rest chest pain with oppression was clinically remarkable in those patients with coronary artery spasm, which was different from effort chest pain in patients with significant coronary stenosis, but twinge without stable relation to effort or rest was the main clinical manifestation in non-spasm and non-stenosis patients. Ischemic change on electrocardiogram was induced during treadmill electrocardiography in only 3 patients of the study group and no ischemic changes in the remaining 49 patients. Reverse redistribution on 201Tl myocardial perfusion imaging was noticed in 48 patients. The sensitivity and specificity of predicting coronary artery spasm by reverse redistribution were 100% and 40%, respectively. To predict coronary artery spasm by combination of reserve redistribution, rest chest pain with oppression and negative treadmill electrocardiogram, the sensitivity remained at 98% but the specificity increased to 90%. Conclusions: Reserve redistribution might be one of the characteristics of coronary artery spasm. The combination of reserve redistribution, rest chest pain with oppression and negative treadmill electrocardiogram might be a rational non-invasive method to predict coronary artery spasm. (authors)