Pregnancy-Associated SCAD Is a Particularly High-Risk Subset of the Condition

Women who have spontaneous coronary artery dissection (SCAD) during or shortly after pregnancy tend to have a more severe clinical presentation when compared with the wider SCAD population, with most cases occurring in the first postpartum month and especially in the first week, a new registry study shows.

Those findings confirm what had been suggested by clinical experience and prior studies based primarily on case reports and provide information that can be helpful for physicians involved in managing these types of patients, according to lead author Marysia Tweet, MD (Mayo Clinic, Rochester, MN).

In the past, many women with SCAD—pregnancy-related or otherwise—were missed or misdiagnosed, Tweet told TCTMD, but diagnosis has improved as gains have been made in awareness of the condition and in cardiac catheterization techniques.

“Really understanding and studying this condition is pertinent because there’s much that’s not known still about presentation, natural history, how to treat these patients, how to follow up on them, and what to expect for the future,” Tweet said. “I think it’s key that we keep an eye on this and continue to study it because it is a high impact event for patients, and they typically are otherwise very healthy, so the usual counseling that we do for people who’ve had a heart attack for other reasons doesn’t quite apply to them.”

SCAD typically occurs in younger people—more commonly in women—who have minimal traditional cardiovascular risk factors. There is an association with pregnancy in roughly 10% to 20% of cases, and SCAD is the most common cause of MI during pregnancy or in the postpartum period. However, pregnancy-related SCAD has not been well described.

[SCAD] is a high impact event for patients, and they typically are otherwise very healthy, so the usual counseling that we do for people who’ve had a heart attack for other reasons doesn’t quite apply to them. Marysia Tweet

The current study, published in the July 25, 2017, issue of the Journal of the American College of Cardiology, provides a more comprehensive look. Tweet and colleagues examined data from the Mayo Clinic SCAD registry, which was started in 2010 and includes both retrospective and prospective information. The analysis included 323 women with SCAD, including 54 (16.7%) with an association with pregnancy. Among them, 48 developed the dissection within 12 weeks of delivering a viable infant, four during pregnancy, one following a first trimester miscarriage, and one following a stillbirth at 36 weeks.

Thirty-five of the 54 women with pregnancy-associated SCAD had dissections occurring in the first month postpartum, and more than half of those were in the first week.

“I think that’s helpful for trying to understand the pathophysiology, because right after delivery all the hormones drop,” Tweet said. “So it’s probably a combined aspect of the hemodynamic stressors of pregnancy and [postpregnancy], with the rapid change in volume and so forth right after delivery, but also a component of hormonal changes, which I don’t think we fully understand.”

Women with pregnancy-associated disease infrequently had atherosclerotic risk factors and tended to have higher-risk presentations, including higher rates of STEMI, left main or multivessel disease, and depressed LVEF, compared with the rest of the cohort. The researchers also found associations between pregnancy-associated cases and multiparity, infertility treatments, and preeclampsia.

One somewhat surprising finding was that women with pregnancy-associated SCAD were less likely to have extracoronary vascular abnormalities (46% vs 77%; P = 0.0032), such as fibromuscular dysplasia. The reason is unclear, Tweet indicated, but the finding “just emphasizes the fact that this is probably a multifactorial process, so multiple things are kind of creating a perfect storm.”

Recurrence an Important Concern for Patients

Commenting for TCTMD, Ram Vijayaraghavan, MD (Rouge Valley Cardiology, Scarborough, Canada), said the study affirms—in a more robust fashion—information that has come from the prior case reports and series on pregnancy-associated SCAD.

The confirmation of various risk factors is particularly important, he said. “These factors that have been identified in case series that we’ve never been 100% sure about were reproduced in this study,” he said. “So it gives us a sense that what we’ve been seeing in the cases is correct, that we do indeed have a higher-risk subset of patients with spontaneous coronary dissection, that pregnancy-associated patients are higher risk when they come in with SCAD. And that may affect how closely we monitor them, what treatments we offer, repeat catheterization, or even [whether we move] toward intervention or surgery.”

Another key piece of information came from following the patients over time, Vijayaraghavan said, noting that his patients with SCAD often ask about risk of the problem recurring. Through a median of 2.3 years in this study, SCAD recurred in 51 patients. Estimated 5-year recurrence rates were 10% for pregnancy-associated cases and 23% for other cases (P = 0.18).

Vijayaraghavan said that he hopes this study will help raise awareness of pregnancy-associated SCAD even further and that he expects to see more studies coming out of registries in Canada, the United States, Europe, and elsewhere in the coming years to help answer remaining questions.

Heather Gornik, MD (Cleveland Clinic, OH), expresses a similar sentiment in an accompanying editorial: “I hope the field has now achieved adequate momentum, and that we will soon see an exponential proliferation of clinical and translational research studies to further understand the pathogenesis of SCAD, to identify mechanisms for primary and secondary prevention, and to determine the best treatment approach.”