By Esther Kim, MD

The vast majority of patients presenting to the emergency department with acute coronary syndrome have atherosclerosis as an underlying pathology. So a young patient—particularly a young woman—who is admitted with acute coronary syndrome or myocardial infarction (MI) can be perplexing when angiography fails to show severe occlusive coronary artery disease (CAD). In such cases, the treating physician should have a high index of suspicion for spontaneous coronary artery dissection (SCAD).

Presentations of SCAD

SCAD may present on angiography in one of three ways:

1. As a classic dissection, with streaking of contrast apparent
2. As a long area of diffuse stenosis
3. As a mild narrowing. This is the most-often underdiagnosed form. When viewing these lesions with ultrasound or optical coherence tomography (OCT), an intramural hematoma will be visible.

Excellent visual examples of all three types are available in a free article on SCAD in this journal article from the American Heart Association.

Why a correct diagnosis is critical

The typical SCAD patient is a female aged 30 to 50. Pregnancy is a well-known cause of SCAD, but almost half of patients with SCAD do not have a known predisposing factor.

SCAD has also been associated with stresses resulting from extreme exercise, very high blood pressure or cocaine use, as well as numerous connective tissue disorders, including Ehlers-Danlos and Marfan syndrome, and systemic inflammatory conditions such as lupus.

Recent findings suggest 60 percent to 80 percent of patients with SCAD have fibromuscular dysplasia (FMD), so tests for this disease should be conducted.

Treatment for SCAD

Treating SCAD conservatively with medications is appropriate in the majority of cases. Often, the dissection heals spontaneously.

Sometimes when there is ongoing ischemia, attempts at revascularization may be necessary. However, the decision should be made only after careful consideration and as a last resort, since stenting an injured artery may potentially worsen the dissection. Uncommonly, urgent bypass surgery may need to be performed.

Looking ahead

Although we don’t yet know what causes SCAD, or whether it can be prevented, we are taking diligent steps to find answers. Cleveland Clinic is one of two U.S. medical centers and 20 Canadian centers participating in a prospective international SCAD registry. We are enrolling all patients presenting with acute MI who are diagnosed with SCAD and following them for three years.

At Cleveland Clinic, we also plan to start a registry of patients with prior coronary dissections to ascertain the natural history of this disease.

SCAD is a rare condition, and the ability of a physician to recognize it can be lifesaving. Consultation with a vascular disease specialist can be most helpful for these patients in the evaluation of potential arteriopathies. SCAD patients can be complex and often require a multispecialty treatment plan.

Esther Kim, MD, is a staff physician in the Department of Cardiovascular Medicine, Sections of Vascular Medicine and Preventive Cardiology in the Women’s Cardiovascular Center.