Giant Coronary Aneurysm Causing Ostial Occlusion of Coronary Artery by Mass Effect: A Case Report.

Coronary atherosclerosis can rarely lead to complications like giant coronary aneurysm (GCA), and acute myocardial infarction (AMI) due to thrombosis in the GCA is even rarer. Multimodality imaging is preferred over relying solely on selective coronary angiogram in such cases due to the limitations of invasive coronary angiogram in visualizing thrombosed aneurysms. We report a rare case of a patient with ST-elevation myocardial infarction caused by ostial occlusion of a right coronary artery (RCA) due to mass effect created by thrombosis in a GCA, thereby highlighting a mechanism of AMI that has not been previously described in GCA. Multimodality imaging led to the correct diagnosis and detection of the underlying mechanism, which had been completely missed by invasive coronary angiography (ICA). We also discuss the utility of multimodality imaging in such cases.