CTO (Chronic Total Occlusion) is a condition where the coronary arteries are 100% blocked for at least 3 months. This blockage, which is usually caused by atherosclerosis and hardens over time due to calcium buildup, completely obstructs the blood flow to the heart muscle.

This condition, which is particularly common in patients with diabetes, high blood pressure and high cholesterol, significantly increases the risk of heart attack if left untreated. The most prominent symptoms are chest pain, shortness of breath and limitations in daily activities.