Fibromuscular Dysplasia Clinical Phenotype Manifesting as a Distal Spontaneous Coronary Artery Dissection in a Middle-Aged Man.

Fibromuscular dysplasia (FMD) is a non-atherosclerotic, non-inflammatory vascular disease of medium-sized arteries that causes abnormal cellular growth in arterial walls and most commonly affects young to middle-aged women (20-50 years of age). While FMD often involves the renal arteries, it can affect any arterial bed. FMD has a characteristic angiographic appearance of a "string of beads." However, rarely patients may present with an FMD-like clinical phenotype without characteristic angiographic FMD evidence. An FMD phenotype consists of a specific constellation of arterially-induced symptomatology (e.g., pulsatile tinnitus in cerebrovascular FMD) in the setting of acute arterial disturbances typically found in FMD (e.g., arterial dissection). This case report discusses a cerebrovascular FMD clinical phenotype manifesting as a distal spontaneous coronary artery dissection (SCAD) in a middle-aged man with chronic migraines, pulsatile tinnitus, and no prior cardiac history. In this case, a patient presented to the emergency room with elevated high-sensitivity troponin levels and anginal chest pain thought to be secondary to a non-ST-elevated myocardial infarction (NSTEMI). A left heart catheterization revealed non-obstructive atherosclerosis and a spontaneous coronary artery dissection in the distribution of the distal left anterior descending artery. To assess potentially involved arterial beds, further work-up consisting of a bilateral carotid and renal artery duplex demonstrated significant carotid arterial tortuosity, a finding consistent with cerebrovascular FMD. Per consultation with neurology and cardiovascular surgical services, a computed tomography angiography (CTA) aorta and CTA head and neck were obtained, which demonstrated subtle irregularities and tortuosities concerning for FMD but without characteristic findings. Further medical optimization was initiated for blood pressure and migraine symptomatology control. After completion of the diagnostic FMD work-up, the patient was discharged with monthly cardiovascular and neurological follow-up. This case report illustrates the important multifactorial practice of history-taking, laboratory evidence evaluation, and diagnostic imaging interpretation to ascertain the correct diagnosis in an atypical presentation of an uncommon disease spectrum.