Fibromuscular Dysplasia in SCAD Tied to Worse Long-term Prognosis

PARIS, France—For patients with spontaneous coronary artery dissection (SCAD), fibromuscular dysplasia (FMD) independently predicts poorer prognosis over the long term, observational data show.

Within a few years after the initial event, the risks of recurrent MI and overall MACE each were more than doubled among those with the blood-vessel disorder, Jacqueline Saw, MD (Vancouver General Hospital, Canada), reported today at EuroPCR 2022.

“We’re a decade into the journey of trying to create awareness about SCAD,” Saw said in an interview with TCTMD. Thanks to that work, “when a woman presents with MI, especially if they’re younger, middle-aged, and have no other cardiovascular risk factors, SCAD does come into consideration now. Awareness is better.”

Among SCAD specialists, too, there has been growing appreciation of FMD as a risk factor, she said. “We’ve been trying to promote [the idea] that all patients with SCAD should be screened for FMD. But has that translated to real-world practice? Not entirely. I would say that probably still about 60% to 70% of patients with SCAD are actually screened for FMD.”

Saw told EuroPCR attendees that screening, when it does happen, identifies a roughly 50% to 80% prevalence of FMD among SCAD patients, with catheter-based angiography getting a higher yield of positives than CT angiography.

“Typically, we would recommend that you do a three vascular territory screening” in the head and neck as well as in the renal and iliac arteries. If anything, the current report underestimates the prevalence, since it wasn’t mandatory for participating centers to screen all three sites or use a particular screening tool, Saw explained.

No Difference in In-Hospital Outcomes

For the study, Saw and colleagues analyzed data from the Canadian SCAD study, identifying 981 patients who underwent screening for FMD. Among them, 50.5% were found to have FMD.

Compared to those without FMD, patients who got the diagnosis were older (mean 53.9 vs 50.3 years) and had a lower body mass index (mean 25.9 vs 28.0 kg/m²; P < 0.001 for both). They were more likely to be female (94.7% vs 85.8%; P < 0.001), postmenopause (60.0% vs 43.0%; P < 0.001), and currently receiving hormone therapy (11.5% vs 7.6%; P = 0.029). They also were more apt to had intracranial aneurysm (7.7% vs 3.5%; P = 0.005) and hypertension (38.2% vs 31.1%; P = 0.022). Other comorbidities were similar in both groups.

There were no differences in pregnancy history, mode of SCAD presentation, possible SCAD triggers, SCAD vessel location or angiographic appearance, LVEF, or management strategy. In-hospital outcomes also were equivalent between the two groups.

Yet, over a median follow-up of 3.14 years, the SCAD patients with FMD had higher rates of recurrent MI (14.5% vs 7.4%; P < 0.001), SCAD (7.7% vs 4.1%; P = 0.021), revascularization (3.6% vs 1.4%; P = 0.041), and MACE (18.0% vs 9.7%; P < 0.001), a composite that included death, MI, stroke/TIA, hospitalization for heart failure, and unplanned revascularization.

On multivariate analysis, FMD carried significantly increased risks of both recurrent MI (adjusted OR 2.23; 95% CI 1.37-3.63) and MACE (adjusted OR 2.08; 95% CI 1.34-3.24). “Other important variables also included younger age less than 50 and presence of intracranial aneurysm,” Saw noted.

Ran Kornowski, MD (Rabin Medical Center, Petah Tikva, Israel), one of the session’s facilitators, asked how knowing about FMD changes management: “When you diagnose FMD among the SCAD patients, do you treat them differently? Do you do something you would not do otherwise?”

There are no known ways to prevent or treat FMD “in terms of reversing the vascular changes that we see,” Saw replied. “But I think what we can do is try to prevent tears in vascular territories already affected by FMD. For instance, if we identify FMD in the cervical neck, we tell patients they should not participate in high-velocity, impact sports or chiropractic neck manipulation.”

Sex hormones have been implicated in the development of SCAD, since the events tend to occur more often among women, and are a key contributor toward MIs among pregnant women in particular, as a 2020 state-of-the-art review notes. This raises the question, Kornowski noted, of how an FMD diagnosis should affect use of hormone replacement therapy (HRT). Saw said that for all SCAD patients, it’s advised that they not continue taking HRT or oral contraceptives. “Having FMD doesn’t necessarily change that recommendation,” she noted.

Nor does having a diagnosis of FMD change the treatment of SCAD, Saw pointed out to TCTMD. However, knowing that a patient has the systemic condition is a reminder for clinicians to be alert to other problems that might appear elsewhere in their body, such as cerebral aneurysm, and to take steps to prevent injuries.