A 30-year-old woman without any risk factor of coronary artery disease presented with continuous chest pain that aggravated 1 hour before admission. Her initial EKG showed ST elevation in lead II, III, aVF. The levels of cardiac enzyme were elevated: CK 1924 U/L (35-172), CK-MB 91.8 U/L (2.3-9.5) and troponin-I 23.2 ng/mL (0-0.05).
Emergent CAG revealed thrombotic total occlusion in proximal RCA. After wiring into RCA, distal flow was restored. But we could see huge saccular aneurysm in mid-RCA filled with thrombi and multiple intracoronary thrombi over middle to distal RCA (Fig. 1). After abciximab infusion, we performed Thrombuster® aspiration device and removed large amount of thrombi (Fig. 2). But majority of thrombi were still remained in aneurismal sac and distal flow was decreased due to distal embolization. Thus we performed balloon angioplasty with 3.0 mm balloon multiple times. Final CAG showed improved distal flow to RCA (Fig. 3).
After PCI, we continued intensive medical therapy and evaluated for the cause of coronary artery aneurysm, such as Kawasaki disease. But no definite clue was found even after extensive screening.

Cardiac CT angiography was performed for the identification of more precise coronary artery morphology. It showed large aneurismal dilatation of proximal RCA with mixed plaque and ulceration (Fig. 4). Follow up coronary angiography was performed after 9 days of intensive medical treatment. In coronary angiography, thrombi in aneurysmal sac were markedly resolved compared with previous coronary angiogram (Fig. 5). IVUS findings revealed a huge aneurysm in the target lesion (Fig. 6)
A congenital aneurysm of coronary artery may be associated with thrombotic total occlusion and a rare cause of acute myocardial infarction in a young patient.