[Acute coronary syndrome due to coronary thrombus formed by severe coronary spasm: a case report].

A 47-year-old man was admitted to our hospital complaining of chest pain at rest in the early morning. Electrocardiography showed ST segment elevation in leads II, III and aVF. Emergency coronary angiography revealed total occlusion of the right coronary artery at the proximal portion. Intracoronary administration of isosorbide dinitrate successfully recanalized the right coronary artery. However, there was a thrombus image at the culprit lesion. Intracoronary administration of urokinase caused the residual thrombus to disappear completely. Follow-up coronary angiography at 1 week and 3 months revealed no organic stenotic lesion. Intravascular ultrasound showed only a little plaque without signs of ruptured plaque in the right coronary artery. Provocation coronary angiography revealed remarkable spasm causing total occlusion at the proximal portion of the right coronary artery. This case suggests that only severe coronary spasm without plaque rupture could form a thrombus causing acute coronary syndrome.