It’s Time to Bring Out the Last Standing Collateral in CLI: Let’s Talk CLI Collaterals in Advanced Disease

Critical limb ischemia (CLI) wears many hats, hence its variable form of presentation. We have seen many different combinations of diseased arteries in CLI. Most common is the multi-level, multi-vessel disease state. As important as opening an occluded artery to restore flow in a CLI patient is, it is also important to keep the collateral vessels intact. This topic leads me to my colleague Dr. Craig Walker, who pioneered the trans-collateral technique to cross complex CLI chronic total occlusions (CTOs). Dr. Walker is the founder and chair of the New Cardiovascular Horizons (NCVH) annual conference, to be held June 1-3, 2016 in New Orleans, Louisiana. Dr. Walker will also share the exciting activities to anticipate at this year’s meeting. It is an absolute honor to interview you, Dr. Walker. 

J.A. Mustapha, MD: Why are collateral vessels so valuable in CLI patients?

Craig Walker, MD: Collateral vessels may not offer an adequate blood supply for a patient to be asymptomatic, or to heal a wound or ulcer, but there is a trickle of blood flow which keeps tissue alive, making the presentation chronic critical limb ischemia rather than acute limb ischemia, which is associated with higher mortality and limb loss.

Dr. Mustapha: In your experience, have you seen a pattern of collateral formation with relation to the profunda?

Dr. Walker: There are many different patterns of profunda collaterals that are noted. When the popliteal segment is patent, then supra-geniculate (at the adductor canal) and geniculate collaterals typically predominate. When the popliteal segment is occluded, then trans-geniculate collateral vessels typically fill the infra-popliteal vessels.

Dr. Mustapha: Can you clarify the difference between trans-collateral vs trans-tibial CTO crossing? Where do you perform trans-collateral versus tibial peripheral vascular interventions?

Dr. Walker: Trans-collateral is different than a trans-tibial approach. Trans-collateral passage allows wire crossing without ever gaining percutaneous access of the tibial vessels. This is followed by externalization of the wire, then antegrade crossing of the occlusion via the externalized wire. This approach is useful when crossing multiple vessels, when there is extensive lower extremity skin infection or recent scar, when tibial vessels are small and densely calcified, and when it is planned to open multiple infrapopliteal vessels.

Dr. Mustapha: Is there a collateral system that you want us to be careful not to disturb or access, and why?

Dr. Walker: When I am treating patients with CLI, I typically save the trans-collateral approach for patients with critical limb ischemia in whom I am concerned that a trans-tibial approach is not ideal. I often utilize the trans-collateral approach as a routine alternative approach in severe claudicants with superficial femoral artery occlusions.

Dr. Mustapha: The pedal collateral system is seldom discussed. Please shed some light on this system for us.

Dr. Walker: The pedal collateral system is crucial in achieving limb salvage, particularly in diabetics. Under normal circumstances, there are rich collaterals to the foot. The peroneal has anterior and posterior communicating branches that serve as collaterals to the anterior and posterior tibial arteries, respectively. The anterior tibial and posterior tibial typically communicate via the lateral plantar branch of the posterior tibial. These are the most common communications, but there are, of course, others.

Dr. Mustapha: Do you have a set approach to treating tibial pedal disease via collaterals after a tibial attempt was not successful?

Dr. Walker: There are two different approaches I utilize. One is to try to cross again, utilizing techniques borrowed from the coronary CTO world with retrograde and antegrade dissection, and in some cases, re-entry tools. The other approach I use if I can’t cross the tibial vessel is to perform pedal loop reconstruction to deliver blood flow to the obstructed pedal vessel.

Dr. Mustapha: The NCVH conference brings us the latest tips and tricks each year. Is there anything in particular that you are excited about sharing for NCVH 2016?

Dr. Walker: As always, we have great live cases from many of the world’s great experts. I believe that this is crucial to learning improved interventional technique. We have our first-ever session on the similarities of coronary CTO intervention and peripheral vessel disease intervention in CLI. I believe that adopting those techniques and equipment will improve CLI interventional success. We have a session on venous reconstructive intervention headed by Dr. Sehdri Raju, who will be giving one of the keynote talks.

Dr. Mustapha: NCVH always covers the spectrum of peripheral vascular disease. What are the CLI-focused sessions this year? 

Dr. Walker: NCVH has had a whole day devoted to just CLI for the past 12 years, but we have actually increased that this year. It is important to note that those sessions not typically attributed to CLI (aortic intervention, common femoral artery intervention, superficial femoral artery and profunda intervention, and popliteal intervention) are all crucial in the interventional therapy of CLI. In addition, combined arterial and venous disease is involved in patients presenting with CLI and ulcers, and I strongly believe that interventionists must understand the significance of these diseases.

Dr. Mustapha: NCVH’s support to fellows has been historical and continues to grow. Any message you would like to relay to program directors and fellows?

Dr. Walker: Our fellows program has continued to grow. Prior participants have fueled this growth. We are dedicated to including them into the interventional community and helping to nurture their growth.

Dr. Mustapha: The Global CLI Society is focusing primarily on awareness in its first year. Do you have any advice or guidance for the new CLI specialist?

Dr. Walker: CLI is a huge problem that is growing worldwide. Interventionists who are willing to take on this challenge must also educate patients, referring physicians, insurers, and policy makers about the importance of this process. We must move towards better early screening, better medical therapy, better follow-up, and better cooperation amongst disciplines.

Dr. Mustapha: Your last word on CLI?

Dr. Walker: I have truly enjoyed my lifetime mission of improving care in patients with CLI. We now have better tools to diagnose, cross, treat, and follow these patients. This disease process is just starting to be recognized for its importance in overall health. The treatment of this disorder has improved because of the efforts of many that have resulted in better recognition and treatment. 

Dr. J.A. Mustapha can be contacted at jihad.mustapha@metrogr.org.