Inflammation and INOCA: Can Fat Attenuation Indexing by Coronary CT Angiography Help Identify Coronary Inflammation?

Hypereosinophilic syndrome (HES) is an inflammatory condition that rarely affects the heart. A 24-year-old woman presented with non-ST-segment elevation myocardial infarction and peripheral eosinophilia. Coronary vasospasm without obstructive coronary artery disease (CAD) was noted on cardiac catheterization, and cardiac magnetic resonance showed resting perfusion defects with multiple punctate infarcts. She ultimately received a diagnosis of HES resulting in ischemia with nonobstructive coronary arteries (INOCA). The presence of coronary inflammation was suggested by a newer coronary computed tomography postprocessing tool called the fat attenuation index (FAI). The FAI has been shown to identify high-risk atherosclerotic CAD and associated inflammation. The role of the FAI in nonatherosclerotic CAD is unknown. This report describes the first case of an abnormal FAI in a young woman with HES and INOCA. Patients with HES may present with coronary artery inflammation that can result in INOCA. There may be a potential role for the FAI in identifying coronary inflammation in INOCA.