Latent coronary spasm during angina-free periods in patients with variant angina. -Comparative study with nitroglycerin administration-.

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Abstract
Coronary artery diameters were analyzed in 13 patients with variant angina and in 12 control patients. Sequential coronary arterial angiography was performed during control periods, during attacks and after administration of nitroglycerin, and coronary vasospasm was documented during anginal attacks and accompanied by electrocardiographic changes in all 13 patients with variant angina. In 7 Patients (Group I) with variant angina, anginal attacks occurred more than 4 times a week, more than twice during the 3 days prior to coronary angiography and in the morning of coronary angiography. In another 6 patients (Group II) with variant angina, attacks occurred less than once a week and never occurred during the 3 days preceding the coronary angiography. Though the degree of coronary stenosis at the sites of spasm was not significantly different between Group I (52.9±23.4%) and Group II (38.3±27.3%) after administration of nitroglycerin, the percent stenosis in the lesions in Group I (77.9±14.1%) was significantly (p<0.01) higher than that in Group II (33.3±28.0%) in the control angiography. Therefore, the degree of stenosis observed in the control angiography decreased significantly (p<0.01) after administration of nitroglycerin in Group I (change in % : -25.0±19.8%), but not in Group II (change in % : 5.0±10.0%). In 12 patients with chest pain syndrome in whom coronary spasm was not demonstrated by infusion of ergonovine maleate, coronary stenosis at control angiography was not changed significantly after nitroglycerin administration. We conclude that coronary spasm appears to be present in the absence of angina event at the time of control angiography and to be closely related to the generation of the anginal attacks in patients with variant angina.