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Chronic Total Occlusion


Chronic total occlusion (CTO) is a condition in which an artery supplying blood to the heart has been completely blocked for at least three months. It's caused by a buildup of plaque (fat, calcium and other substances) on the artery walls. Up to 25 percent of people with coronary artery disease have CTOs.

UCSF is renowned for its heart care programs, and our highly trained experts are experienced in both traditional surgical procedures and minimally invasive techniques for safely and effectively opening blocked arteries. Our team includes cardiologists, interventional cardiologists, surgeons and imaging specialists, and they collaborate closely to thoroughly evaluate each patient and develop the best treatment plan for that individual.

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Signs & symptoms

Unlike an acute – or abrupt – blockage, which typically causes a heart attack, CTOs develop over time. When you have a CTO, your heart is receiving less blood – and therefore less oxygen – than normal. But you may not notice a problem because blood is still reaching your heart through open arteries or through new tiny blood vessels that the heart develops in response to the CTO – as a detour around it. For many people, symptoms show up only during exercise or exertion. These include:

  • Chest pain
  • Fatigue
  • Shortness of breath
  • Decreased ability or inability to exercise
  • Abnormal heartbeats (arrhythmia)

Risk factors for CTO are mostly the same as for coronary artery disease. They include:

  • Family history of the condition
  • Excess weight or obesity
  • High bloodstream cholesterol
  • High blood pressure
  • Insufficient physical exercise
  • History of heart attack
  • History of bypass surgery


The primary test used to diagnose CTO is a coronary angiogram. A catheter (thin, flexible tube) is threaded through a blood vessel in the wrist or groin to an artery in the heart; then a harmless dye that shows up well on X-rays is injected through the catheter. The images reveal blocked arteries as well as how well the heart muscle and valves are functioning.

Our providers review your angiogram results and tailor a treatment plan to your condition and needs. You will then have a clinic visit – either in person or by video – in which we discuss the recommended treatment, including its risks, benefits and what to expect.


The goal of treating CTO is to restore blood flow through the coronary arteries and relieve symptoms. Appropriate treatment depends on how much the condition is affecting the heart – and consequently, the patient.

If you aren't experiencing discomfort or symptoms, we may recommend managing your condition through medications, such as drugs that lower cholesterol or blood pressure. But if symptoms develop, or if your condition is already advanced, we offer two procedures:

  • Coronary artery bypass grafting (CABG). In this open-heart surgical procedure, the surgeon takes a section of healthy artery or vein from elsewhere in your body and grafts (connects) it to the blocked artery. One end is attached above the CTO and one end below, providing a way for blood to bypass the blockage. After CABG surgery, patients typically spend one to two days in intensive care and another three to five days in the hospital before going home. Generally, it takes six to 12 weeks to fully recover.
  • Percutaneous coronary intervention (PCI). This minimally invasive procedure to open blocked arteries is performed by an interventional cardiologist. With the patient under sedation (rather than general anesthesia), the doctor makes a small incision in the wrist or upper leg and – guided by imaging – threads a catheter carrying a tiny balloon and a stent (a mesh tube) through blood vessels until it reaches the CTO. Special instruments conveyed by the catheter are used to break up or push through the blockage. The balloon is then inflated to compress the plaque against the artery walls and the stent is placed to help keep the artery open. Most stents now come coated with timed-release drugs that prevent the growth of scar tissue, helping to ensure good blood flow and reduce the need for further treatment. The procedure takes three to six hours, depending on the degree of difficulty in reaching and removing the particular CTO.

Patients usually spend one night in the hospital for observation after PCI. Most experience immediate relief from symptoms and are able to resume normal activity within a few days. A follow-up visit will be scheduled for 14 to 30 days after the procedure.

UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.

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