SCAD, though relatively uncommon, can have a tremendous impact on its victims, most of whom are very young and who are not felt to be at risk for heart attack or heart disease. While SCAD can affect both sexes and all age groups, about 85% to 90% of cases are seen in women, usually at younger ages than the typical heart attack. SCAD has been reported to account for up to one-quarter of acute coronary syndrome cases (heart attack or angina) in women under the age of 50 years, but can also occur in men and in older and postmenopausal women. Patients with SCAD typically do not have the usual risk factors associated with heart disease (smoking, obesity, high cholesterol, high blood pressure, or diabetes).
Many cases of SCAD have no clear cause, but often its occurrence is linked to the presence of another arterial condition (like fibromuscular dysplasia or connective tissue disorders). These conditions may predispose someone to SCAD by weakening the artery wall so that a tear can more easily occur spontaneously in the tunica intima. In a smaller proportion of patients, it is related to a precipitating stress event, such as an intense emotional jolt or physical stress, drugs, or even bearing-down activities (retching or vomiting, coughing, or bowel movements). These movements likely increase the force exerted upon the coronary artery wall leading to it tearing.
One of the most common conditions linked to SCAD is pregnancy. There is evidence that the milieu of female hormone levels present during pregnancy may be an important contributor to SCAD. It’s unclear how common pregnancy-related SCAD really is, but in two recent studies, 5% of all SCAD cases were pregnancy-related. (See the studies here and here.)