Chronic Total Occlusion (CTO)

Chronic total occlusion (CTO) is a complete or nearly complete blockage of one or more coronary arteries. The blockage, typically present for at least three months, is caused by a buildup of plaque within a coronary artery. When this happens, blood flow to the heart is compromised.

CTO is a common heart disorder in patients with coronary artery disease. Between 20 and 25 percent of patients with coronary artery disease also have a chronically blocked artery.

Risk factors for chronic total occlusion include:


Symptoms of CTO typically occur during times of activity, but may also occur at rest. Symptoms may include:

  • Chest discomfort (pain, pressure or tightness)
  • Shortness of breath
  • Dizziness
  • Fatigue
  • Nausea
  • Pain in the upper body or arm
  • Rapid or irregular heartbeat


Diagnosis of chronic total occlusion is based on a patient’s medical history, a physical exam and a coronary angiogram procedure. During this procedure, contrast material is injected into the coronary arteries and pictures are taken of them. These images reveal whether there are blockages in the coronary arteries and how well the heart muscle and valves are functioning.

The following tests may also be ordered to fully understand a patient’s condition:

  • EKG
  • Echocardiogram
  • Stress test
  • Nuclear medicine PET scan
  • Cardiac MRI


For many patients, treatment for CTO is focused on reducing the risk of future heart-related events and improving symptoms. In the past, treatment options for patients suffering from symptoms of CTO were limited to medication or coronary artery bypass graft (CABG) — an open-heart surgery in which a vein or artery is taken from another part of the body and used to create a new path for blood to flow.

More recently, innovative new methods for treating CTO have been developed, including percutaneous coronary intervention (PCI). For this advanced, minimally invasive procedure, interventional cardiologists use specialized equipment and advanced techniques to place a small mesh tube in narrow or blocked arteries to widen and support the walls of the arteries and restore normal blood flow.

Interventional Cardiology at Michigan Medicine

Michigan Medicine’s multidisciplinary team of interventional cardiologists has expertise in the diagnosis and treatment of patients with chronic total occlusion as well as specialized training in advanced methods to treat CTO blockages, including percutaneous coronary intervention procedures. Our cardiac interventionalists specialize in the full range of CTO PCI procedures. 

Make an Appointment

To make an appointment to learn about what treatments for CTO may be right for you, call the University of Michigan Frankel Cardiovascular Call Center at 888-287-1082 or visit our Make a Cardiovascular Appointment page, where you can learn what to expect when you call us.