Presented at the Cardiovascular Research Foundation’s third international CTO Summit, held in February 2006, several renowned investigators highlighted new methods and success rates for crossing chronic total occlusions with the latest innovative approaches. The clinical and angiographic factors predicting success and failure of CTO revascularization, summarized by Dr. Jeffery Moses, continue to emphasize what little has changed in the anatomy of the CTO over the past 20 years of percutaneous coronary intervention. The newest technical approaches employ novel support catheters such as the Tornus, vibrating penetrating catheter guidewire systems, combinations of new material guidewires, and laser or radiofrequency ablation of obstructing CTO tissue.

It is also helpful to all involved in the treatment of CTOs to review the rules of engagement as proposed by Dr. Moses. Procedural stopping points should be strongly recommended and include distal perforation, device exit from the anticipated lumen and the evident futility of success after several hours of effort. In addition, when fluoroscopic time has exceeded 45 minutes, procedure time more than 2? hours or contrast media loads in excess of 500 cc, it would be wise to stop, and if possible, try again on another day.

Advancements in the success of CTO crossing have been provided by new guidewires and guidewire techniques. The drilling, penetration and sliding methods described by experienced operators appear to contribute to higher success rates. Drilling through a CTO using soft or intermediate guidewires is a method that is most commonly applied. Penetration and sliding through micro channels of a subtotal occlusion as occurs in in-stent restenosis has some advantages. Conditions that affect CTO guidewire success include tip stiffness and torque transmission. Tip stiffness decreases with the greater distance the wire is extended from the microcatheter. Torque transmission is proportional to tip stiffness within straight artery segments, but is reduced in highly tortuous regions. Additional materials and techniques employ advanced composition guidewires, dual injection angiography, biplane imaging, extraluminal and reentrant (guided by intravascular ultrasound) technique, parallel wire techniques and extra support backup catheters have been proposed. My bottom line for CTO management in the cardiac cath lab is the following:

1. Before starting, weigh the odds by considering the features of high CTO success based on angiography and available clinical information, especially the estimated age of the CTO.

2. Select appropriate initial guidewires, backup support guides and special support catheters for guidewire drilling.

3. Attempt standard wires before starting with hydrophilic guidewire. However, if possible, limit creation of large false channels.

4. Use new technology sparingly at first, until experience grows. Concentrate skills in a small group of operators until success rates improve.

5. Learn the rules of engagement and know when to quit.

Correction

To err is human, and I did by omitting the Angio-Seal hemostasis device (St. Jude Medical, Minnetonka, MN) from my June letter, Push, Pull, Click, Stitch. Angio-Seal is a collagen anchor deployed through the arterial sheath inside the artery. It is then pulled back to form a sandwich-type seal, with a collagen wrap on the outside of the artery sealing the puncture site between the anchor and the wrap. This device is among the easiest, quickest and most reliable hemostasis devices.

M. Kern