SCAD: Spontaneous Healing Common With Conservative Treatment

Megan Brooks

March 01, 2019

Most coronary arteries affected by spontaneous coronary artery dissection (SCAD) heal spontaneously on repeat angiography, with the vast majority completely healed after 30 days from the SCAD event, new research suggests.

"Our results are reassuring and support the current recommendation for conservative therapy for low-risk patients with SCAD, i.e., in the absence of hemodynamic instability, ongoing ischemia, or critical anatomy (left main dissection, or multivessel proximal dissections)," Saber Hassan, MD, and colleagues from the division of cardiology, Vancouver General Hospital and University of British Columbia, Canada, conclude.

Their study is published online February 27 in JACC: Cardiovascular Interventions.

Although SCAD is relatively uncommon, it is now increasingly recognized as an important cause of acute coronary syndrome among young and middle-aged women. However, little is known about the timing and angiographic healing characteristics with SCAD.

Hassan and colleagues did a retrospective analysis of angiographic healing after an acute SCAD event. It is the largest angiographic series with repeat coronary angiography after SCAD, and involves 156 patients (182 noncontiguous lesions), they say.

"We objectively reviewed each repeat angiogram for angiographic criteria of healing, which required meeting all 3 criteria of (1) improvement of angiographic stenosis, (2) residual stenosis <50%, and (3) normal TIMI-3 flow," they explain.

The mean age of patients in the cohort was 51.5 years, 88.5% were women, 83.3% were Caucasian, and 75.6% had fibromuscular dysplasia. All patients presented with myocardial infarction (MI).

At index angiography, type 2 SCAD was most commonly observed (126/182 lesions; 69.2%), TIMI grade flow below 3 was present in 85 lesions (46.7%) and median lesion stenosis was 79.0%, which improved to 25.5% on repeat angiography.

The majority of SCAD lesions (86.3%) treated conservatively healed spontaneously, the researchers found, but there appeared to be a time-dependency to angiographic healing.

For the 11.5% of lesions that did not fulfill the healing criteria, many of the angiograms were performed early after the SCAD event, 73% of which were for recurrent MI or recurrent symptoms. Of the repeat angiograms performed less than 30 days after the SCAD event, only ~23% showed angiographic healing, whereas 95% of angiograms performed at 30 days and beyond showed angiographic healing, they note.

"In the absence of instrumentation with angioplasty or stenting, the natural history of SCAD appear to be spontaneous healing with gradual resorption of the intramural hematoma and tacking up of the intimal flap against the deeper arterial walls," they write.

The researchers say they didn't identify angiographic characteristics — such as lesion length, stenosis severity, and SCAD angiographic subtypes — that predicted spontaneous healing of SCAD lesions. The only baseline clinical differences were worse ejection fraction and early repeat angiography for patients with unhealed lesions.

Less Is More Approach to SCAD

In an accompanying editorial, Dirk Sibbing, MD, and Ralph Hein, MD, Ludwig Maximilian University and the German Center for Cardiovascular Research, Munich, congratulate the authors for their "distinguished work in scrutinizing these patients including a considerable amount of data on baseline and procedural characteristics during initial and repeat coronary angiography, as well as information on clinical outcome during long-term follow-up."

Sibbing and Hein say the high healing rate of more than 90% argues against routine invasive angiographic follow-up. "Instead, a computed tomography (CT) scan to control for lesion healing could be a valid approach for some SCAD patients, but the study by Hassan et al. lacks data on the diagnostic precision of this method after SCAD," they suggest.

A coronary CT scan might not provide diagnostic certainty for some distal SCAD lesions, but it might be applicable for noninvasive assessment of healing in the proximal coronary arteries, they add. "A study comparing both diagnostic modalities with focus on precise visualization in affected coronary vessels is warranted in this patient population."

For now, there remain many open questions in the field of SCAD on a variety of fronts, including its pathophysiology, genetic background, predisposing conditions, morphologic SCAD characteristics associated with lack of healing, and even the choice and duration of antiplatelet therapy for different lesion subsets, the editorialists say.

"Collaborative research efforts, such as the recently started EORP (European Observational Research Platform) SCAD study, are needed for a better understanding of this disease. For the time being, we may summarize that a 'less-is-more' approach must be considered as the first-choice treatment strategy for most of our SCAD patients," Sibbing and Hein conclude.

The authors have declared no conflicts of interest related to this research. Sibbing has received speaker fees and honoraria for consulting from Bayer Vital, AstraZeneca, Sanofi Aventis, Pfizer, and Roche Diagnostics, as well as research grants from Roche Diagnostics and Daiichi Sankyo. Hein has reported that he has disclosed no relevant financial relationships.

JACC Cardiov Int. Published online February 27, 2019. Abstract, Editorial

 

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