Spontaneous coronary artery dissection — sometimes referred to as SCAD — is an uncommon emergency condition that occurs when a tear forms in a blood vessel in the heart.
SCAD can slow or block blood flow to the heart, causing a heart attack, abnormalities in heart rhythm or sudden death.
SCAD most commonly affects women in their 40s and 50s, though it can occur at any age and can occur in men. People who have SCAD often don't have risk factors for heart disease, such as high blood pressure, high cholesterol or diabetes.
SCAD can cause sudden death if it isn't diagnosed and treated promptly. Seek emergency attention if you experience heart attack symptoms — even if you think you aren't at risk of a heart attack.
Signs and symptoms of SCAD may include:
- Chest pain
- A rapid heartbeat or fluttery feeling in your chest
- Pain in your arms, shoulders or jaw
- Shortness of breath
- Unusual, extreme tiredness
When to see a doctor
If you experience chest pain or think you might be having a heart attack, call 911 or your local emergency number. If you don't have access to emergency medical services, have someone drive you to the nearest hospital. Drive yourself only as a last resort.
It's not clear what causes SCAD. However, doctors and researchers have found some similarities among people who have had SCAD.
Risk factors for SCAD include:
- Female sex. Though SCAD can occur in both men and women, it tends to affect women more than men.
- Recent childbirth. Some women who have had SCAD have recently given birth. SCAD has been found to occur most often in the first few weeks after delivery.
Underlying blood vessel conditions. Fibromuscular dysplasia (FMD), which causes irregular growth of cells in artery walls, is associated with SCAD. FMD can weaken artery walls, leading to blockages, dissections or aneurysms. It can also cause high blood pressure, stroke and tears in other blood vessels. Women are more likely to have FMD than men.
Diseases that cause inflammation of the blood vessels, such as lupus and polyarteritis nodosa, have also been associated with SCAD.
Arteries that are twisted (tortuous arteries) are more common among people who have had SCAD.
- Inherited connective tissue diseases. Genetic diseases that cause problems with the body's connective tissues, such as vascular Ehlers-Danlos syndrome and Marfan syndrome, have been found to occur in people who have had SCAD.
- Very high blood pressure. Severe high blood pressure can be associated with SCAD.
- Illegal drug use. Using cocaine or other illegal drugs may increase your risk of SCAD.
It's not clear whether extreme or intense physical exercise and severe emotional stress increase the risk of SCAD. Researchers have noted that there may be a connection, but more research is needed.
SCAD is a tear inside an artery that carries blood to the heart. When the inner layers of the artery separate from the outer layers, blood can pool in the area between the layers. The pressure of the pooling blood can make a short tear much longer. Blood trapped between the layers can form a blood clot (hematoma).
SCAD may slow blood flow through the artery, which makes the heart muscle weaken. Or blood flow through the artery may be completely stopped, causing heart muscle to die (heart attack). A heart attack that occurs in SCAD is different from a heart attack caused by hardening of the arteries (atherosclerosis).
SCAD can happen more than once, despite successful treatment. It may recur soon after the initial episode or years later. People who have SCAD may also have a higher risk of other heart problems, such as heart failure due to the damage to the heart muscle from heart attacks.
Doctors are studying why SCAD recurs and who is most likely to experience a recurrence.