SOLACI | Latin American Society of Interventional Cardiology

How to Choose the Best Approach in Chronic Total Occlusions, by Dr. Jean-Michel Paradis

CTO are present in around 16 to 20% of patients with coronary artery disease who get a coronary angiography. CTO Percutaneous intervention has been on the rise, mainly due to equipment and technique advancement.

During his presentation, Dr. Paradis mentioned the 7 principles of CTO:

– The primary indication of CTO PCI is symptom improvement.

– Dual coronary angiography must be used in every case.

– A microcatheter is essential for guidewire support.

– There are 4 strategies for CTO: antegrade wire escalation, antegrade with dissection and reentry, retrograde wire escalation, retrograde with dissection and reentry.

– Changes in equipment and technique increase success rate and improve procedure efficacy.

– Centers and professionals dedicated to CTO should count on the necessary equipment to optimize success and minimize complications.

– We should optimize stent deployment, including the frequent use of intravascular ultrasound.

These principles have led to increased success rate of these PCIs. This is why several algorithms have been created to carry out these procedures. One of them is the Global CTO Crossing Algorithm which includes 10 steps.

Step 1: Dual angiography (at least the collateral circulation should have exclusive ipsilateral origin). Most CTO techniques can be done with 7 Fr catheters.

Step 2: Carefully assess the angiography. You must pay careful attention to proximal CAP morphology, length and CTO composition, distal vessel quality and collateral circulation.

Step 3: Planning an ambiguous proximal cap. This might be solved by doing an angiography in different projections or by injecting contrast on the microcatheter. Dr. Paradis discovered three strategies to challenge the old proximal CAP, which are IVUS guided puncture, via retrograde access or using CAP modifying techniques.

Step 4: Distal vessel quality or distal CAP bifurcation. In these cases, retrograde access might be safer and more effective.

Step 5: Assess whether the retrograde option is feasible. It is preferred to access septal branches seeing as the use of epicardial branches involve higher risk of cardiac tamponade.

Step 6: Antegrade strategies. Are the most used for CTO, unless presented with an ambiguous proximal CAP or poor-quality distal vessel. Should the antegrade wire escalation strategy fail, we should use the antegrade with dissection and reentry.

Step 7: Retrograde strategy. This should be considered to solve ambiguous proximal CAP cases, when there is distal CAP bifurcation or when antegrade access is not viable.

Step 8: Changing the strategy when the initial one shows no progress. The algorithm developed by the Japanese recommends changing strategy after 20 minutes.

Step 9: In case crossing CTO failed, we should wait over 2 months after a second attempt.

Step 10: Deciding when to finish. Operators should wrap up the procedure when it has extended over 3 hours, contrast volume is 3 times higher than glomerular filtration, radiation dose is higher than 5 Gy, patient and/or operator are exhausted, or when there are serious complications.

In conclusion, algorithms for CTO are useful tools to optimize success and safety of CTO PCI.