Chronic Total Occlusion

A chronic total occlusion (CTO) is a blockage in your coronary arteries, the blood vessels that supply blood to your heart. The blockage is usually the result of a fatty substance called plaque building up and narrowing your arteries. You’re more likely to develop a CTO if you have coronary artery disease.


What is a chronic total occlusion?

A chronic total occlusion (CTO) is a total blockage in one of your coronary arteries lasting three or more months. Your coronary arteries are the blood vessels that carry blood to your heart. CTOs restrict blood flow to your heart, which can lead to chest pain, shortness of breath or a heart attack.

Who may get a chronic total occlusion?

Chronic total occlusions are more common in people who have coronary artery disease (CAD). Up to 1 in 3 people with CAD also have a CTO.

The risk factors for the development of a CTO are very similar for CAD. You are more likely to develop a CTO if you smoke or have other risk factors such as:

How common are chronic total occlusions?

CTOs are more common as people get older. CTOs affect:

  • About 37% of people under age 65.
  • About 40% of people ages 65 to 79.
  • About 41% of people older than 85.

The actual prevalence of CTOs could be higher than experts estimate. Some CTOs don’t cause symptoms, so people may have a CTO without a formal diagnosis.


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Symptoms and Causes

What are the symptoms of a chronic total occlusion?

CTO symptoms may include:

CTO symptoms often worsen when you exert yourself and lessen during rest. However, you may also experience symptoms while at rest. You may also have no symptoms at all.

What causes a chronic total occlusion?

Chronic total occlusions typically occur when a fatty substance called plaque builds up in one or more of your coronary arteries. This plaque buildup, called atherosclerosis, leads to artery narrowing and hardening. When atherosclerosis occurs in your coronary arteries, it’s called coronary artery disease.


Diagnosis and Tests

How is a chronic total occlusion diagnosed?

Healthcare providers typically diagnose a chronic total occlusion using a coronary angiogram. During a coronary angiogram, your provider injects a contrast dye into your blood vessels. The dye highlights your blood vessels on an X-ray and shows how blood moves through your coronary arteries.

Your provider may also use tests such as a:

Management and Treatment

How is a chronic total occlusion treated?

A CTO treatment plan typically focuses on lowering symptoms and reducing your risk of a heart-related event such as a heart attack. The treatment you need depends on how severe your symptoms are and whether you are already on a treatment plan for CAD. Your provider may recommend:

  • Percutaneous coronary intervention (PCI): Your provider inserts a small, hollow tube (catheter) through a blood vessel in your groin or wrist. They guide the catheter to your coronary artery, then inflate a small balloon in the artery to move plaque out of the way. They place a small mesh tube (stent) in the artery to keep it open and restore blood flow.
  • Coronary artery bypass graft (CABG): This is an open heart surgery in which your provider takes an artery or vein from elsewhere in your body and uses it to create a detour around your blocked coronary artery.


Outlook / Prognosis

What is the outlook for a chronic total occlusion?

A chronic total occlusion is a serious condition, but treatment can help. Some research has shown that PCI successfully treats a CTO in up to 86% of patients. Other studies have shown that CABG successfully treats the condition in around 60% of patients.

Living With

What questions should I ask my healthcare provider?

If you have a chronic total occlusion or think you could, you may want to ask your healthcare provider:

  • What are the early signs of a CTO?
  • What tests do I need to diagnose a CTO?
  • What lifestyle changes can I make to reduce the chances of developing a CTO?
  • What are the treatment options for a CTO?
  • What are the chances that I’ll develop a CTO again after treatment?

A note from Cleveland Clinic

A chronic total occlusion is a complete blockage in one of your coronary arteries that has been present for three months or longer. A CTO restricts blood flow to your heart and can cause serious complications, including a heart attack. The goal of treatment is to manage symptoms. It often includes a percutaneous coronary intervention or a coronary artery bypass graft. Both options have high rates of successfully treating a CTO.

Medically Reviewed

Last reviewed on 08/03/2022.

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