A 41 year old male hypertensive smoker presented with acute abdominal pain and transient widespread ST elevation on the ECG. Coronary angiography (panel A) revealed a mobile opacity in the proximal left main stem (arrow) and a slow flow phenomenon in the left anterior descending artery. Treatment was given with aspirin, clopidogrel, low molecular weight heparin and a tirofiban infusion over three days. Repeat angiography showed identical appearances in the left main stem with normal flow in the left anterior descending artery. Intravascular ultrasound of the left main stem (panel B) showed a non-occlusive atherosclerotic plaque (X) with adherent thrombus (Y). An attempt to aspirate the thrombus using the Rescue thrombosis management system failed. The lesion was therefore treated with stenting using a 4.5 × 13 mm Ultra bare metal stent, post-dilated to 5 mm (panels C and D). The patient made an uneventful recovery. Repeat angiography is planned at four months.