Coronary steal syndrome is a condition in which blood is taken from a narrowed artery in the heart and rerouted to — in other words, stolen by — other blood vessels.

This condition can occur when some medications widen arteries and increase blood flow. This can also happen after coronary artery bypass grafting (CABG) or result from a congenital heart problem.

Coronary steal syndrome can cause chest pain when you do not have enough blood flow to your heart muscle (ischemia). It can also increase your risk of a heart attack. Surgery is often necessary to relieve symptoms and restore healthy circulation in the heart.

Read on to learn more about what causes coronary steal syndrome, what symptoms to watch out for, and how this condition can be treated.

When blood flow through a narrowed coronary artery ends up being “stolen” by nearby healthy blood vessels, the obstructed artery has been “robbed” of its usual healthy blood flow.

The result of this obstruction — called “coronary steal syndrome” — can develop after an artery becomes blocked due to atherosclerosis. This happens when plaque builds up in the heart’s arteries. It’s also the primary risk factor for a heart attack.

In some cases, coronary steal syndrome happens when narrowed arteries are treated with vasodilators. These medications cause blood vessels to expand in order to improve blood flow.

But even though a vasodilator may help open up an obstructed artery, it can also expand otherwise healthy arteries and offer blood flow in the heart an easier path.

A 2017 study in the World Journal of Cardiology also suggests that coronary steal syndrome may develop after CABG when newly grafted blood vessels fail to supply nearby arteries with sufficient blood.

A 2021 study in the Journal of the American Heart Association notes that about 41 percent of coronary steal syndrome cases happen because of congenital heart disease. An atypical attachment between a vein and an artery in the heart — called an “arteriovenous fistula” — is especially a risk factor for coronary steal syndrome.

While coronary steal syndrome affects arteries within the heart, other types of steal syndromes involve blood vessels in other parts of the body.

Arterial steal syndrome

The distal arteries are those farthest away from the heart, such as the blood vessels in your hands.

Undergoing dialysis for kidney conditions may require an arteriovenous fistula. This may raise the risk of arterial steal syndrome. Pain, discoloration, and numbness in the affected hand are the main symptoms.

Revascularization procedures can often improve circulation to the distal arteries. This restores healthy blood flow to arteries that may have been affected by reduced blood flow due to coronary steal syndrome.

Some examples of revascularization procedures include:

  • Angioplasty: A doctor puts a ballon-like device into your artery and inflates it. This expands the artery and allows blood to flow through more easily. After removing the balloon, the doctor may also insert a small metal tube called a stent that can keep the artery expanded, helping blood to flow through the artery more easily.
  • Atherectomy: A doctor removes plaque from the artery that’s blocking proper blood flow. This may be used if it’s too hard or risky to insert a stent in the artery.

Subclavian steal syndrome

The subclavian arteries are blood vessels that extend out from the right and left sides of your aortic arch. They help carry blood to the upper body, including your brain.

Blockage in one of the subclavian arteries can cause blood flow to reverse within the artery, “stealing” blood from the brain.

Revascularization through stenting or bypass surgery is often effective.

Vascular access steal syndrome

Healthy blood flow can sometimes be disrupted by an arteriovenous fistula or a synthetic vascular graft, which is a device installed in your arm that connects to an artery and a vein during dialysis treatments for kidney disease.

Your fingers and hands can become numb or painful when blood is routed away from them. Procedures to repair the artery-vein connection are usually needed to avoid major complications, such as neuropathy.

Mild cases of coronary steal syndrome may have no obvious symptoms. But as the condition progresses, chest pain typically becomes the primary symptom.

Other symptoms can include:

Subclavian steal syndrome can cause:

  • headaches
  • dizziness
  • loss of vision

Arterial steal syndrome or vascular access syndrome can also cause:

  • hand pain
  • differences in pulses and blood pressure between one arm and the other

When should you seek immediate medical attention?

Sudden chest pain should always be considered a medical emergency, especially if you’ve already received a diagnosis of any type of heart condition.

Call 911 immediately when chest pain is also accompanied by shortness of breath or a severe headache.

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Coronary steal syndrome is often discovered during imaging tests used to screen for other conditions. If you have unexplained chest pain, a doctor may order one or more of the following tests that can help confirm a diagnosis of coronary steal syndrome or other cardiovascular problems:

  • Cardiac stress test, with or without exercise. In some cases for this test, a doctor may give you a vasodilator to see if expanded blood flow in non-obstructed arteries triggers ischemia.
  • Coronary angiography. This test uses a special dye in the bloodstream detectable by X-rays to track blood flow within your heart and reveal narrowed coronary arteries.
  • Computed tomography (CT) scan. A CT scan uses computer technology and moving X-rays to generate a cross-section image of the area being scanned.
  • Doppler ultrasound. This uses sound waves to create images of your subclavian arteries and check for reversed blood flow.
  • Positron emission tomography (PET) scan. A PET scan uses a dye with radioactive tracers that your tissues or organs can absorb, allowing a doctor to look at blood flow in your coronary blood vessels.

The main goal of treatment is to improve circulation in a narrowed artery so that the blood supply is no longer “stolen” from the organs and tissue that need it. Treatments for coronary steal syndrome include:

  • Endovascular procedures that use catheters. Doctors use these to inflate balloons within narrowed arteries or implant stents to keep the arteries open.
  • Open-heart bypass surgery. This procedure takes a blood vessel from elsewhere in your body and attaches it to the narrowed artery, routing circulation around the blockage.
  • Endarterectomy. This is a surgical procedure used to remove plaque from inside an artery and enhance blood flow.
  • Endovascular coiling. A tiny spring-like coil is implanted near the atypical artery-vein connection to reroute blood toward the region experiencing poor circulation. It’s often used to treat steal syndrome complications in people receiving dialysis or who recently underwent CABG.

Living with coronary steal syndrome means following some of the guidelines recommended to people with coronary artery disease, diabetes, or other conditions that threaten healthy circulation. These guidelines include:

  • quitting smoking
  • eating a heart-healthy diet, such as the Dietary Approaches to Stop Hypertension (DASH) diet
  • exercising regularly under the supervision of a healthcare professional
  • maintaining typical blood pressure, cholesterol, and blood glucose levels
  • reducing stress
  • getting about 8 hours of sleep per night

You may also work closely with a cardiologist so that you’re taking medications as prescribed and keeping current with all your checkups.

Coronary steal syndrome is rare but usually treatable with catheter-based procedures or open surgery.

Once blood flow is restored to healthy levels, you should be able to resume your everyday activities without chest pain or other symptoms. But if you’ve had a problem in one artery, your odds of having other vascular concerns are greater.

Living a heart-healthy lifestyle and following a doctor’s guidance should help reduce future complications and prepare you to respond if troubling signs appear again.