Chronic Coronary Occlusion

Excerpt

Chronic coronary occlusion or chronic total occlusion (CTO) refers to complete luminal diameter stenosis with resultant thrombolysis in myocardial infarction (TIMI) grade flow 0 or 1. In such, there is no anterograde flow due to collaterals. The occlusion should be of at least three months' duration to be labeled as chronic. The main vessels that are affected due to CTO are the right coronary artery (43% to 55%), the left anterior descending artery (approximately 24%), and the left circumflex artery (17%-20%). Functional CTOs represent severe occlusion, but not a complete occlusion of the coronary arteries. Such functional CTOs have collateral circulations presenting as anterograde flow. However, even such collateral flow is unable to sustain future ischemic events in functional CTOs, indicating a need for revascularization.