SCAD Heart Attacks: Outcomes Not as Bad as Previously Feared

To find out the natural history of non-atherosclerotic spontaneous coronary artery dissection (SCAD), a prospective cohort study found that the risk of longer-term recurrent dissections and other cardiovascular events was lower than expected.

Based on 750 consecutive SCAD patients who had heart attacks and were treated largely conservatively, the long-term survival was “excellent” given a 3-year death rate of just 0.8%, according to Jacqueline Saw, MD, of Vancouver General Hospital. , and colleagues from the Canadian SCAD (CanSCAD) cohort study.

Overall major adverse coronary events (MACE) reached 14.0%, including a 9.9% incidence of recurrent myocardial infarction (MI) split into prolongations of prior SCAD (3.5%), de novo recurrent SCAD (2, 4%) and iatrogenic catheter-induced dissection (1.9%), they reported in the Journal of the American College of Cardiology.

“Our finding of low MACE rates and mortality up to 3 years is remarkably low compared to older published reports,” Saw’s group said. “Previously, MACE rates of up to 30% were reported at 2 to 3 years of follow-up, mostly caused by recurrent MI from recurrent SCAD, which was reported in 15% to 22% of patients.”

It is likely that the older registry-based reports were biased due to the retrospective and prospective enrollment of higher-risk SCAD patients artificially inflating MACE rates, the authors suggested.

The current report “suggests a better prognosis and reduced risk of SCAD recurrence in less selected, more representative SCAD patients,” agreed Alexandre Persu, MD, PhD, of Cliniques Universitaires Saint Luc in Brussels, and colleagues in an accompanying editorial. . “Overall, these data will provide patients with some reassurance.”

It is well documented that younger women are disproportionately affected by SCAD as a cause of MI. Still, many questions remain about the natural history and treatments in SCAD due to a lack of prospective and randomized studies in the literature.

Notably, the great majority of CanSCAD individuals continued to use aspirin and beta-blockers through a 3-year follow-up. Neither therapy had a significant impact on 3-year event rates, in contrast to previous findings by Saw and colleagues.

“While the latest findings generate more uncertainty about the usefulness of these drugs after SCAD, prospective randomized controlled trials are underway to address this question,” Persu’s group noted.

Similarly, neutral results were observed in people undergoing in-hospital revascularization in the current cohort study. The nearly 15% of SCAD patients who had initial revascularization – percutaneous coronary intervention (PCI), usually reserved for those with persistent ischemia, and coronary artery bypass graft (CABG) for those with left main or extensive proximal multivessel SCAD – had no difference in MACE after discharge compared to conservatively managed peers.

“We have observed in clinical practice that sometimes the pendulum has swung too much to the conservative side, with, for example, patients with persistent ischemia and ST elevation being treated medically. It is hoped that our data will provide some reassuring evidence that if PCI whether CABG should be pursued, the long-term outcomes after revascularization would be beneficial,” Saw’s group wrote.

CanSCAD was a prospective, observational study of people with acute coronary syndrome at 22 centers in 2014-2018. Participants were required to have non-atherosclerotic SCAD documented on coronary angiography and confirmed by core laboratory results.

The cohort was on average 51.7 years old and 88.5% were female. About one in three had ST segment elevation MI (STEMI) and two in three had non-STEMI. Patients reported an accelerated emotional stressor in 50.3% of the cases and a physical stressor in 28.9%.

Predisposing conditions included fibromuscular dysplasia in 42.9%, peripartum condition in 4.5% and genetic disorders in 1.6%. These factors emerged as independent predictors of 3-year MACE on multivariate analysis, although this should be interpreted as hypothesis-generating, the CanSCAD authors cautioned.

They also acknowledged that, despite their efforts to enroll all consecutive SCAD patients, their study did not capture people who died before coming to hospital, those who did not undergo coronary angiography, and those whose SCAD diagnosis was missed on coronary artery disease. angiography.

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    Nicole Lou is a reporter for MedPage Today, where she covers cardiology news and other advances in medicine. Follow

disclosures

The study was funded by the Canadian Institutes of Health Research, Abbott Vascular, AstraZeneca, St. Jude Medical and Servier.

Saw disclosed support from and/or relationships with the Canadian Institutes of Health Research, Heart & Stroke Foundation of Canada, NIH, University of British Columbia Division of Cardiology, AstraZeneca, Abbott, St. Jude Medical, Boston Scientific, Servier, Michael Smith Foundation of Health Research, Sunovion, Baylis, Gore and FEops. Co-authors revealed support from and/or relationships with multiple entities.

Persu disclosed no industry relations. A co-author revealed relationships with Abbott Vascular, AstraZeneca and General Electric.

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