CTO
Also written as: CTO — Chronic Total Occlusion
Chronic total occlusion, a complete blockage of a coronary artery that has been present for more than three months.
Full Definition
Chronic total occlusion (CTO) refers to a complete blockage of a coronary artery that has been present for at least three months, as evidenced by angiographic absence of antegrade flow (TIMI 0 flow) through the vessel. CTOs represent a complex subset of coronary artery disease and are found in approximately 15-30% of patients undergoing coronary angiography. These lesions are characterized by mature fibrous tissue, calcification, and often extensive collateral circulation. Percutaneous coronary intervention for CTOs requires specialized techniques and equipment, with success rates varying based on lesion complexity. The development of dedicated CTO programs and techniques has improved procedural success rates significantly.
Usage
Usage note: Distinguish from acute occlusions; requires documentation of duration when known.
In Context
- "The RCA CTO was successfully recanalized using retrograde approach via septal collaterals." — Complex PCI procedure note
- "CTO of the LAD with extensive collateral filling from the RCA system was noted on angiography." — Diagnostic catheterization