Abstract 16282: Coronary Fibromuscular Dysplasia Angiographic Manifestations

Background: We previously described a strong association between fibromuscular dysplasia (FMD) and spontaneous coronary artery dissection (SCAD). Angiographic manifestation of coronary FMD aside from dissection was reported to be rare. However, we observed several non-dissection coronary angiographic abnormalities in patients with multifocal FMD. Methods: Baseline demographics and imaging of patients with suspected non-dissection coronary FMD at Vancouver General Hospital were retrospectively reviewed. Presence of multifocal FMD in non-coronary territories was confirmed by 3 specialists. Coronary angiograms with suspected coronary FMD changes (excluding dissected segments) were reviewed and classified by 2 experienced angiographers for: (1) irregular stenosis (beading) - multiple areas of stenosis in a focal or diffuse pattern and with/without systolic accentuation, (2) smooth stenosis - diffuse or focal, (3) segmental dilatation/ectasia, and (4) tortuosity. Optical coherence tomography (OCT), if performed, were reviewed by 2 specialists. Results: Of 28 patients with multifocal FMD and suspected coronary involvement on angiography, 23 were women (82.1%), mean age was 58.6 ± 9.5, and mean BMI was 24.6. Sixteen presented with myocardial infarction (10 due to SCAD), 12 underwent angiography for stable or atypical angina. The observed coronary angiographic abnormalities were: irregular stenosis (beading) in 14 (12 diffuse, 2 focal, 3 with systolic accentuation), smooth stenosis in 6 (4 diffuse, 2 focal), segmental dilatation/ectasia in 14 (majority with multi-segmental, diffuse enlargement in an entire vessel), and tortuosity in 25 cases. Fourteen patients had OCT of the abnormal segments showing abnormalities distinct from atherosclerosis. These included multiple areas of patchy or diffuse intimal, medial or adventitial abnormalities with disorganized fibrotic thickening, proteoglycan accumulation, macrophage infiltration, loss of elastic membranes, and cavitation. Conclusions: This is the first case series describing angiographic manifestations of coronary FMD, which can be categorized into irregular stenosis, smooth stenosis, dilatation and tortuosity, representing features that are additional to dissection.