Chronic total occlusion (CTO) is a condition where a coronary artery has been completely blocked for at least 3 months. CTO intervention is an advanced cardiological procedure that enables opening of these blocked vessels using special techniques.
What is CTO?#
Chronic total occlusion (CTO) is a condition where a coronary artery is 100% blocked and this blockage has persisted for at least 3 months. CTO is detected in approximately 15-25% of patients undergoing coronary angiography.
Characteristics of CTO:
- Vessel is completely blocked (TIMI flow 0)
- Blockage has been present for at least 3 months
- Contains hard, fibrotic, and calcified tissue
- Collateral vessels have developed
Why is CTO Important?#
The heart muscle in the blocked vessel area is supplied through collateral (side) vessels. However, this supply is usually insufficient and leads to:
- Angina: Chest pain occurring with exertion
- Shortness of breath: Especially with exertion
- Heart failure: In the long term
- Arrhythmias: Due to scar tissue
- Decreased quality of life: Limitation of daily activities
Who is CTO Intervention Suitable For?#
Patient selection for CTO intervention should be done carefully:
Indications#
- Angina persisting despite medical treatment
- Presence of viable myocardium in CTO territory
- CTO supplying a large myocardial area
- Symptoms affecting quality of life
- Patients unsuitable for bypass surgery
Contraindications#
- No viable tissue in CTO territory (scar)
- Very small vessel
- Patients with short life expectancy
- Severe comorbidities
Pre-CTO Intervention Evaluation#
Comprehensive planning is required for successful CTO intervention:
Imaging:
- Coronary angiography (bilateral injection)
- Coronary CT angiography
- Myocardial viability testing (MRI, PET, SPECT)
Lesion Assessment:
- J-CTO score (difficulty level)
- Occlusion length
- Degree of calcification
- Collateral vessel quality
- Proximal cap morphology
CTO Intervention Techniques#
CTO intervention requires special techniques different from standard angioplasty:
Antegrade Approach#
Approaching the occlusion in the normal flow direction (proximal to distal):
Antegrade Wire Escalation (AWE):
- Crossing the occlusion with guidewires of different stiffness
- First preferred technique
- Successful in short, straight CTOs
Antegrade Dissection and Re-entry (ADR):
- Entry into subintimal space
- Controlled dissection
- Re-entry to true lumen (CrossBoss, Stingray)
Retrograde Approach#
Approaching the occlusion from the reverse direction through collateral vessels:
- Septal collaterals (most common)
- Epicardial collaterals
- Bypass grafts
Retrograde Wire Escalation:
- Reaching distal cap through collateral
- Crossing the occlusion from reverse direction
Reverse CART (Controlled Antegrade and Retrograde Tracking):
- Meeting of antegrade and retrograde wires
- Gold standard in complex CTOs
Hybrid Approach#
The “hybrid algorithm” is used in modern CTO intervention:
- Strategy determination based on lesion characteristics
- Rapid technique change in case of failure
- Combination of antegrade and retrograde techniques
Special Equipment Used in CTO Intervention#
| Equipment | Usage Area |
|---|---|
| Microcatheters | Wire support and exchange |
| CTO guidewires | Different stiffness and tip shapes |
| CrossBoss | Subintimal crossing |
| Stingray | Re-entry |
| Rotablation | Calcified lesions |
| IVUS/OCT | Intravascular imaging |
CTO Intervention Success Rates#
Success rates with experienced CTO operators:
- Overall success rate: 85-90%
- With antegrade techniques: 60-70%
- With retrograde techniques: 80-90% (in antegrade failure cases)
- With hybrid approach: 90%+
Factors affecting success:
- Operator experience
- Lesion complexity (J-CTO score)
- Appropriate equipment
- Patient selection
CTO Intervention Risks#
CTO intervention carries higher risk compared to standard angioplasty:
Common (1-5%):
- Access site complications
- Contrast nephropathy
- Radiation exposure (long procedure time)
Rare (<1%):
- Coronary perforation
- Tamponade
- Collateral damage
- Myocardial infarction
- Need for emergency bypass
- Death
After CTO Intervention#
After successful CTO intervention:
Short Term:
- Rapid improvement in symptoms
- Increase in exercise capacity
- Improvement in quality of life
Long Term:
- Improvement in left ventricular function
- Decrease in arrhythmias
- Survival advantage (in some studies)
Frequently Asked Questions#
Is CTO intervention better than bypass surgery?
How long does CTO intervention take?
What happens if CTO intervention fails?
How long is recovery after CTO intervention?
Can every CTO be opened?
Appointment and Contact#
If you would like to schedule an appointment for CTO evaluation or treatment:
📍 Avrasya Hospital - Beştelsiz Mah. 101. Sokak No:107, Zeytinburnu, Istanbul
📞 Phone: +90 212 665 50 50 (Ext: 4012)
This content has been prepared by Assoc. Prof. Dr. Habib Çil for general informational purposes. Please consult a cardiology specialist for definitive diagnosis and treatment.
Related Coronary Interventions#
Other coronary treatments related to CTO intervention:
- Coronary Angioplasty - Balloon and stent vessel opening
- Cardiac Stent - Drug-eluting stent implantation
- Cardiac Angiography - Coronary artery imaging
- Atherectomy - Plaque removal procedure
- Coronary Artery Disease - About coronary artery disease