Majority of SCAD Lesions Heal With Conservative Treatment

The majority of spontaneous coronary artery dissection (SCAD) cases heal over time when managed with the currently recommended conservative treatment approach, according to a new analysis of patients with SCAD undergoing repeat coronary angiography.

Among the 156 patients with 182 lesions included in this latest series, more than 95% of SCAD lesions spontaneously healed when assessed by angiography 30 or more days after the acute event, report researchers.

“Unless you really have ongoing ischemia, these patients can be managed conservatively,” senior investigator Jacqueline Saw, MD (University of British Columbia, Vancouver, Canada), told TCTMD. “Avoid PCI and the vast majority of these arteries will heal. So I think our paper has a very important message for interventional cardiologists: leaving these arteries is not a bad thing unless [the patient] meets the criteria for intervention.”

In the absence of hemodynamic instability, ongoing ischemia, or critical anatomy (such as a left-main coronary artery dissection or multivessel proximal dissections), the American Heart Association and European Society of Cardiology currently recommend conservative medical therapy for low-risk patients with SCAD.

Avoid PCI and the vast majority of these arteries will heal. Jacqueline Saw

The condition is “somewhat rare,” said Saw, but it’s an important cause of ACS in young and middle-aged women. Although its exact cause is unknown, fibromuscular dysplasia, pregnancy, and hormone therapy are believed to predispose individuals to SCAD. It occurs when there is a separation of the coronary artery wall caused by intramural hemorrhage that results in a false lumen (with or without intimal tear). The resulting intramural hematoma compresses the arterial lumen and compromises blood flow, which in turn can cause myocardial ischemia or infarction.

No Wires, No Stents, No Balloons

In the present study, which was led by Saber Hassan, MD (University of British Columbia), and published February 27, 2019, in JACC: Cardiovascular Interventions, the investigators included patients with SCAD who were prospectively followed at Vancouver General Hospital. Patients were referred from hospitals in British Columbia and also from surrounding provinces.

The mean age of individuals with SCAD was 51.5 years. Of the patients included in the series, 88.5% were female and more than 75% had fibromuscular dysplasia. All patients presented with MI, of which 77.6% had NSTEMI. Among those included, the prevalence of cardiovascular risk factors was low, with just 5.1% having diabetes and 25.6% having dyslipidemia. Of the 182 noncontiguous SCAD lesions on index angiography, the left anterior descending artery was most commonly affected (48.9%) followed by the left circumflex (28.6%) and right coronary (22.5%) arteries. The median time to repeat angiography, which was at the discretion of the treating physician, was 154 days.

Spontaneous angiographic healing was defined on the basis of three parameters: an improvement in stenosis severity from the index event, a residual diameter stenosis less than 50%, and TIMI grade 3 flow. Overall, spontaneous healing on the follow-up angiogram was observed in 157 lesions (86.3%). Of the 25 lesions that did not meet the criteria for healing, repeat angiography to evaluate 17 lesions was performed early during follow-up. When the analysis was restricted to repeat angiography performed ≥ 30 days from the index SCAD, spontaneous healing was observed in 95% of the lesions.

To TCTMD, Saw said the conservative management of SCAD avoids any instrumentation of the coronary artery—no wiring, no stenting, and no ballooning. “We know that outcomes with PCI can be quite poor for this condition,” she said. “Medical therapy typically would entail continuing aspirin and beta-blocker indefinitely and we usually also use an ADP antagonist for short duration, which is anywhere from 1 to 12 months.”    

The prevalence of SCAD is currently unknown, mainly because it’s underdiagnosed. Saw said that awareness of SCAD is growing and more and more physicians are picking it up on coronary angiograms. “It’s still missed, even by very seasoned interventionalists, but it’s getting better,” she said. “The more you see the better you are at picking it up, but we’re not quite there yet, especially among lower-volume interventionalists.”

‘Less Is More’ Should Be the First Approach

In an editorial, Dirk Sibbing, MD, and Ralph Hein, MD (Ludwig-Maximilians-Universität München, Germany), note that the recognition and identification of SCAD is “somewhat intricate and a conservative treatment is not first nature to many interventional cardiologists.” However, they support the “less-is-more” approach and stress that is should be the first-choice treatment strategy for most SCAD patients.

A conservative management strategy might also sound confusing to patients, who may have been informed they’d had a heart attack only to be told they actually don’t have a conventional blockage and won’t be getting a stent or surgery, said Saw. So this new evidence showing the vast majority of SCAD lesions will heal naturally provides reassurance to them as well.

The editorialists point out that because there was only a small number of unhealed SCAD lesions, and most of these lesions were diagnosed within 30 days after the initial SCAD event, it was impossible to evaluate predictors of spontaneous healing. “Much larger studies would be needed to enable a reliable assessment of distinct variables that are associated with delayed or complete absence of complete SCAD healing (eg, age, gender, lesion length, type of dissection, proximal versus distal lesions),” write Sibbing and Hein.

Finally, they state that given the high rate of spontaneous healing, routine angiographic follow-up is unnecessary. CT imaging, although limited as a modality in this setting, could be a valid approach for some SCAD patients. 

Saw agreed that the routine angiographic follow-up is not recommended. If the patient has high-risk anatomy and is managed conservatively, then a repeat angiogram may be considered. Also, if recurrent chest pain occurs after SCAD and there is ischemia on stress testing or lifestyle-limiting angina, then a repeat angiogram might also be an option, she noted.