Impact of fibromuscular dysplasia on early and late clinical outcome in patients with spontaneous coronary artery dissection

Background and Purpose Spontaneous coronary artery dissection (SCAD) is frequently associated with fibromuscular dysplasia (FMD), two predominantly female arteriopathies often diagnosed in middle-aged women. However, the reported overlap between SCAD and FMD varies widely (11–86%), and data regarding the prognostic impact of FMD on outcomes after SCAD remain inconsistent. Therefore, we aimed to assess the prevalence of FMD and its association with clinical outcomes following SCAD in a large prospective study. Methods We analyzed SCAD patients who had complete angiographic data, at least one follow-up visit and a complete FMD screening. FMD was defined according to American Heart Association criteria as multifocal disease with a “string-of-beads” appearance in at least one extracoronary vascular bed. The primary endpoint was a composite of major adverse cardiovascular events (MACE) including death, recurrent myocardial infarction, stroke and heart failure hospitalisation. Results Of 1,114 patients with SCAD, 456 patients (40.9%) had FMD in at least one vascular bed. Patients with FMD were significantly older than those without FMD (median age 54 vs. 51 years; p < 0.001) and had a higher prevalence of hypertension (37.5% vs. 31.2%; p=0.036). In addition, the proportion of women was significantly higher in the FMD group compared with the non-FMD group (95.6% vs. 86.6%; p < 0.001). Patients with FMD exhibited a significantly higher incidence of MACE over a 3-years compared to patients without FMD (14.9% vs. 10.3%; log-rank p = 0.023). Considering the substantial proportion of early events, a landmark analysis was conducted: During the early post-SCAD phase, the incidence of MACE was comparable between groups (log-rank p = 0.261). However, beyond the 10-day landmark, patients with FMD demonstrated a significantly higher event rate than those without FMD (7.8% vs. 4.7%; log-rank p = 0.033) (Figure 1). After multivariable adjustment the presence of FMD remained an independent predictor of MACE at 3 years (hazard ratio [HR] 1.55; 95% confidence interval [CI] 1.08–2.21; p = 0.016). Conclusion FMD is present in approximately 40% of patients with SCAD and an independent predictor of MACE at 3 years. These findings highlight the importance of systematic FMD screening and long-term surveillance in this high-risk subgroup.