Spontaneous coronary artery dissection — sometimes referred to as SCAD — is an 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, heart rhythm problems (arrythmias) 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 have heart attack symptoms — even if you think you aren't at risk of a heart attack.
Spontaneous coronary artery dissection (SCAD)
A tear develops on the inside of a coronary artery, allowing blood to create a split between two layers of the wall. This may result in a loose flap of tissue on the inside of the artery. Sometimes, the split remains small, but the blood in between the layers can clot. This clot, called an intramural hematoma, may cause the normal artery channel to become narrow, blocking blood flow to the heart.
Symptoms of SCAD can include:
- Chest pain
- A rapid heartbeat or fluttery feeling in the chest
- Pain in the arms, shoulders, back or jaw
- Shortness of breath
- Unusual, extreme tiredness
When to see a doctor
If you have 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.
The cause of spontaneous coronary artery dissection is unknown.
Risk factors for SCAD include:
- Female sex. Though SCAD can occur in both men and women, it tends to affect women more than men.
- 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, but it can also occur during pregnancy.
- Fibromuscular dysplasia (FMD). This condition, which causes irregular growth of cells in artery walls, 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.
- Hormone use. Hormone therapy, such as from oral contraceptives or infertility treatments, has been associated with SCAD.
- Other conditions affecting blood vessels. Diseases that cause inflammation of the blood vessels, such as lupus and polyarteritis nodosa, also have been associated with 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 might increase the risk of SCAD.
Some episodes of SCAD have occurred after extreme or intense physical exercise and severe emotional stress.
Blood flow in arteries in spontaneous coronary artery dissection (SCAD)
In spontaneous coronary artery dissection (SCAD), a tear forms in an artery in the heart. This can cause blood to pool in the area between the layers. Blood trapped between the layers can form a blood clot (hematoma). SCAD can reduce or block blood flow through the artery, which can cause a heart attack. However, a heart attack as a result of SCAD is different from a heart attack caused by hardening of the arteries (atherosclerosis), shown in the bottom image.
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 between the layers. The pressure of the pooling blood can make a short tear longer. Blood trapped between the layers can form a blood clot.
SCAD can slow blood flow through the artery, which weakens the heart muscle. Or blood flow through the artery can stop, causing heart muscle to die (heart attack). A heart attack as a result of SCAD is different from a heart attack caused by hardening of the arteries (atherosclerosis).
SCAD can happen more than once, despite successful treatment, either soon after the first episode or years later. People who have SCAD can also have a higher risk of other heart problems, such as heart failure due to the damage to the heart muscle from heart attacks.