Coronary Angiographic Manifestations and Outcomes in Spontaneous Coronary Artery Dissection Patients With and Without Fibromuscular Dysplasia.

BACKGROUND: Fibromuscular dysplasia (FMD) is widely recognized as an important predisposing condition for spontaneous coronary artery dissection (SCAD). However, it remains unclear in SCAD patients with coexistent extracoronary FMD whether SCAD can be attributed to coronary FMD.

METHODS: We retrospectively analyzed consecutive patients enrolled in our Vancouver SCAD registries between September 2009 and October 2019 who were screened for extracoronary FMD. We reviewed coronary angiograms for manifestations of coronary FMD that were previously described (ie, irregular stenosis, smooth stenosis, dilatation/ectasia, and severe tortuosity). Outcome of interest was major adverse cardiovascular event (MACE).

RESULTS: We included 346 SCAD patients, of these, 250 (72.3%) had extracoronary FMD. Patients with FMD were older (54.6 ± 9.5 vs 51.7 ± 9.8 years) and more likely to have prior history of myocardial infarction (7.2% vs 1.0%, P = 0.047) and stroke (4.4% vs 0%, P = 0.081) compared with non-FMD patients. On coronary angiography, severe tortuosity was more prevalent in patients with extracoronary FMD (58.4% vs 36.5%, P < 0.001). Rates of irregular stenosis, smooth stenosis, and dilatation/ectasia were numerically higher in patients with extracoronary FMD, but differences were not significantly different. The rate of MACE at median follow-up of 807 (interquartile range, 392-1096) days was not different between groups (19.6% vs 15.6%; non-FMD as a reference: hazard ratio 1.44; 95% confidence interval, 0.76-2.71, P = 0.261).

CONCLUSION: SCAD patients with extracoronary FMD were more likely to have coronary FMD manifestations on angiogram, especially severely tortuous vessels, compared with those without extracoronary FMD, with similar clinical outcomes. This may suggest that SCAD can occur at sites of pre-existent subclinical coronary FMD.