Unstable angina complicated by vasospasm and intracoronary thrombus and no evidence of plaque rupture

A 57-year-old man came to the emergency room because of abrupt chest pain for 30 min. ST elevations in inferior lead were normalized following sublingual nitroglycerin. He performed an exercise test on Bruce protocol and exercised up to 12 min (13 METs) without chest pain and ST-T changes on the next day. We performed coronary angiography to rule out coronary vasospasm; however, we did not perform provocation test due to thombus in the culprit lesion. After medical treatment for 6 days, follow-up coronary angiogram revealed no thrombus in the previous site and intravascular ultrasound did not demonstrate plaque rupture. We concluded that prolonged spasm might cause prolonged coronary flow limitation and induce acute thrombus formation without plaque rupture. This finding may be an important pathogenesis of acute coronary syndrome in patients with variant angina.