What is Chronic total occlusion (CTO)

Chronic total occlusion (CTO) is the 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. This prevents the free flow of blood to the part of the heart, which is supplied by that artery. Without enough blood flow, the heart does not receive oxygen and nutrients, which compromises its functionality resulting in chest pain (angina). CTO is commonly found in patients with coronary artery disease. Around 25–10 % of patients with coronary artery disease develop chronic coronary artery blocks.

How Chronic total occlusion is developed?

Blockages of the coronary arteries, which also includes CTOs, are the result of coronary artery disease. In this condition, the lining of arteries is damaged and narrowed over time as fatty deposits collect and plaque develops. The process is known as atherosclerosis. In patients with complete/total blockage/CTO, an alternate circulation to the heart, which is referred to as collateral circulation, is developed. However, the collaterals won’t provide sufficient flow to the heart muscle (myocardium) and treatment is required.

Risk Factors for CTO include

  • High Cholesterol
  • Diabetes
  • High blood pressure
  • Smoking
  • Alcohol consumption
  • Obesity

Symptoms of Chronic total occlusion

  • Chest Pain
  • Shortness of breath
  • Dizziness
  • Fatigue
  • Nausea
  • Pain in the arm, sometimes radiating to neck and back
  • Irregular heartbeat

Diagnosis of Chronic total occlusion

Chronic complete occlusion diagnosis is based on the medical history of a patient, a physical examination and a coronary angiogram procedure. During this process, the coronary arteries are injected with contrast material and photographs are taken of them. These photos show if the coronary arteries have blockages and how well the heart muscle and valves work.

The following tests are also recommended to understand a patient’s condition:

  • 2D-Echocardiogram
  • Stress test
  • Coronary CT

Chronic total occlusion Treatment

CTO treatment focuses on reducing the risk of future heart-related events and improving symptoms. Previously, the treatment of CTO was only limited to medication or coronary artery bypass graft (CABG). CABG is an open-heart surgery in which a vein or artery is taken from another part of the body and is used to create a new path for blood to flow.

Nowadays, Percutaneous Coronary Intervention (PCI) is the gold-standard treatment for CTO, which is a less invasive technique. Interventional cardiologists perform this surgery. They use specialized equipment and advanced techniques for placing a stent (small meshed tube) in blocked arteries to widen and support the walls of arteries and restore normal blood flow.

CTOs can be heavily calcified or extremely fibrotic and the treatment of such lesions is considered to be highly challenging.


  • Western Approach:Predominantly Constitutes *ADR(Antegrade Dissection Re-entry)Strategy.
  • Japanese Approaches:Predominantly Constitutes Retrograde Strategy.

CTO PCI Procedure

CTO PCI is a technique for the treatment of CTO blockages by experienced cardiac interventionalists with extensive training in advanced methods. Depending on the severity of the blockages, the procedures range in length from two to five hours. In order to be tracked, all patients are admitted to the hospital overnight after the operation. One of the few centres in India to use a mix of antegrade (forward-moving like dissection/re-entry) and retrograde (backwards-moving) methods for accessing the blockage is Medicover Hospitals. When a blockage occurs, to assist with blood flow, new blood vessels known as collateral blood vessels are formed around the blockage. The doctor inserts a catheter into these collateral arteries using advanced guide wires, accessing the blocked artery from various sides. A small uninflated balloon is inserted at the tip of the catheter using a procedure called balloon angioplasty and inflated while in the artery. Along with stents, this technique is used to establish a larger opening in the arteries to restore blood flow.

How Safe is the Procedure?

CTO PCI is a relatively safer procedure when compared to open heart surgeries. However, as with any other procedure, it also has a minor risk of complications, such as:

  • Excessive bleeding at the puncture site
  • Blood vessel damage at the puncture site
  • Sudden closure of coronary artery
  • Small tear in the artery's inner lining
  • Cardiac arrest

Benefits of CTO PCI

  • Improvement in symptoms
  • Improvement in left ventricular function
  • Improvement in functionality and survival rate


Chronic Total Occlusion interventions are considered as the last mile of learning for any cardiology team. Chronic total occlusions are long-standing (>3 months) 100% occlusions of the coronary arteries and are found in 10–20% of the patients undergoing coronary angiographies.

Our Cardiology team at Medicover Hospitals took these challenging surgeries to a new level in the Indian Subcontinent by making world-class hardware available 24x7 in our cath lab.

Our accumulated experience of these surgeries in the last 11 years has catapulted the success rate of these interventions to > 96% compared to any other world-class cardiac intervention centre.

Our interventionists, at Medicover Hospitals, proctor and train cardiologists all over India and in South-East Asian countries to make collective wisdom reach last-mile needy individuals

Recent CTO case performed by our Doctor at Medicover Hospitals

Dr P. Venkata Ramana, a veterinary doctor in Kurnool was told by doctors of various hospitals that he should travel to Japan to get the CTO intervention done to treat his condition. Later a doctor recommended him to Dr. Sharath Reddy, Sr. Consultant Interventional Cardiologist in Medicover Hospitals. Today Dr. Venkata Ramana has completely recovered and is all praises for the treatment provided by Dr. Sharath Reddy. He thanked Dr Sharath Reddy, his team, and Medicover Hospitals for the advanced technology and expertise available in Medicover Hospitals.

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Frequently Asked Questions

1. How is chronic total occlusion treated?

The aim of chronic coronary complete occlusion (CTO) treatment is to restore blood flow to the heart through a blocked or occluded artery. Angioplasty and stenting were ineffective in treating CTOs in the past, so doctors had to resort to bypass surgery to restore blood flow to the heart.

2. Can a total occlusion be stented?

Traditional stenting can also be used to treat coronary arteries with serious blockages of up to 99%. A coronary chronic total occlusion, or CTO, occurs when an artery becomes fully blocked.

3. What is chronic occlusion?

Chronic total occlusion (CTO) is the 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. This prevents the free flow of blood to the part of the heart, which is supplied by that artery.

4. What is chronic total occlusion of artery of the extremities?

Chronic total occlusions (CTO) are a form of peripheral artery disease in which cholesterol and inflammatory cells fully block the vessel, preventing any blood from flowing to the arm or leg.


https://www.sciencedirect.com/science/article/abs/pii/S0002914905001906, Chronic Total Occlusion
https://www.jacc.org/doi/full/10.1016/S0735-1097%2801%2901349-3, Outcomes of Chronic Total Occlusion