The CLI CTO: When, Where, and How to Best Cross

Introduction

J.A. Mustapha, MD

Crossing of the critical limb ischemia (CLI) chronic total occlusion (CTO) remains one of the most challenging aspects of CLI therapy.  The operator must determine when in the patient’s presentation to initiate therapy, where to obtain access, how to best cross the CTO, and what closure device or method to use.

In CLI, the CTO is never straightforward and tends to be associated with many additional obstacles. With us during this issue is Gary Ansel, MD, who has had a long history of treating CTOs and has pioneered many of the currently used CTO crossing methods both above and below the ankle. Dr. Ansel is an interventional cardiologist who serves as System Medical Chief – Vascular Services at OhioHealth in Columbus, Ohio.  Dr. Ansel is one of the founders and a member of the board of directors of VIVA Physicians. This year, the annual VIVA conference will be held September 18-22, 2016 (vivaphysicians.org).

J.A. Mustapha, MD: Dr. Ansel, when you think of the CLI CTO, what is the first thing that comes to your mind?

Gary Ansel, MD: “Success stratification.” The variables for our group are where, length, reconstitution of a named vessel, and calcification. Once we have those variables evaluated, we stratify it as one procedure, two procedures, and high success (>95%) or low (70%). We start to plan for success. The “where” is divided into above the knee or below the knee. The length is short or long, and typically for our lab, short means less than 20 cm, and long means more than 20 cm. The reconstitution is whether there is a named vessel downstream, and calcification is severe vs non severe.  

Dr. Mustapha: CTOs, in general, are challenging. How do you implement a different plan of attack when dealing with 300-600 mm CTOs?

Dr. Ansel: CTOs are not created equally. Length is one component, but the other variables I mentioned seem to play a larger role. I did not mention one other factor that can affect ease of crossing, and this is a previous bypass. The bypass anastomotic area distally can really affect the ease of re-entry due to scarring, changing the tissue plane and fibrotic density of the occlusion.  

Dr. Mustapha: Operators still gaining experience often ask about how best to treat a flush superficial femoral artery (SFA) CTO that reconstitutes at the P1 level.  Beside surgical bypass, what is your advice to approaching this type of CTO?

Dr. Ansel: I find these cases can be completed with a high degree of success and rarely send them to bypass anymore. Even when flush occluded, you can typically find the ostium using an angled catheter such as a Judkins right (JR)-4. Once located, I will typically utilize a short JR-4 guide catheter through a braided sheath as well as a telescoping braided crossing catheter for enough support.  I then utilize a .035-inch, straight, stiff, hydrophilic guidewire for crossing the CTO. If the ostium is too calcified, I will use one of many devices to get through the cap. The luminal crossing catheters that use either a sharp tip or some form of energy will often allow you to obtain enough purchase to cross. Keeping it simple is my mantra. Though they are referred to as luminal devices, most of the time I find myself subintimal and either the wire re-enters on its own, or I then go to a re-entry catheter. (Yes, these cases can be expensive.) In the rare case where there is difficulty and the ostium is not heavily calcified, I will often just puncture P1, come back retrograde, and use the techniques in reverse order. At the OhioHealth Vascular Institute, CTOs are a separate membership criteria, requiring 80% success. Thus we have to plan very well. 

Dr. Mustapha: Starting to cross a CTO is usually the easy part. Do you have any advice to the readers on when to stop? What signs or tips trigger you that it is time to stop?

Dr. Ansel: This is a great question. Certainly, a perforation that we are having trouble controlling may make us reverse anticoagulation and rethink the procedure, but that is very rare. In our lab, we will not stop until 2 operators have put their heads together and have not progressed. We also stop if the patient’s tolerance of the procedure is becoming an issue. As I have gained more experience through the years, I think it makes you much more time efficient, and I will typically only stop if I have run through my various options and am still not making progress. I want to stress the second opinion part. If someone is going after a CTO that is a little out of their norm, I highly recommend going over the case with a more experienced operator or doing the procedure with a more experienced operator to improve the learning process, as well as the chances of a successful procedure for the patient. I am very lucky to have great partners and even today will often go over a tough procedure with them before starting. We encourage our younger partners to do the same thing.

Dr. Mustapha: The CLI CTO seems so unpredictable, often with no rhyme or reason as to its presence. The most perplexing CLI CTO is one that starts in P2 or P3, and reconstitutes in the distal tibials at the level of the anterior and posterior communicating arteries. Can you advise your thoughts on an approach to crossing such an onerous CTOs?

Dr. Ansel: As you point out, these are, in my opinion, some of the toughest cases. I know I sound redundant, but pre-procedure planning is extremely important. If the patient has a wound, you want to document whether the plantar arch is patent and thus angiosome is less important, or closed, where you want to be very deliberate as to which vessel you are going to try to open. I will place a 90 cm, braided, 5 French (Fr) sheath to the popliteal artery.  I do this instead of a 4 Fr system due to the potential need for an aspiration catheter (these don’t typically go through a 4 Fr). I will then utilize an .018-inch braided and angled crossing catheter, and an .018-inch gold-tipped hydrophilic guidewire. Even after all these years, I keep coming back. I will then try to angle the catheter toward the vessel I want to open. If I am not having much success, I will go to a 4 Fr angled catheter and an .035-inch angled wire. If still not having success, I will assess for a collateral vessel to go through and come back retrograde, or complete a puncture on the pedal/tibial vessel I want to open and cross retrograde. 

Dr. Mustapha: Many operators, including myself, learned tips and tricks on CTO crossing during the VIVA live cases.  Can you tell us what to expect this year?

Dr. Ansel: Thanks for the nice compliment. VIVA always attempts to be educational and demonstrate good, successful technique. This year there will be discussion not only regarding the tools, but the economics that are affected by decision making. As many institutions are moving to “valued care”, we will have to take the success and need for repeat procedures into consideration, beyond the upfront device costs.

Dr. Mustapha: CTO complexity varies and CTO crossing rates vary. With that in mind, are we are at a point where we should hold ourselves accountable to a successful CTO crossing rate? 

Dr. Ansel: Absolutely. As noted above, our multi-institutional OhioHealth Vascular Institute now makes it a separate membership. After reviewing the data, we chose 80%, even though some hospitals have a >90% success rate. Even measuring this variable makes our institute different and encourages member interaction. To assist members, the OhioHealth Vascular Institute put on a CTO course for members. The members will often bring up complex cases for discussion, bringing them to a more experienced operator. Members will then do the case together or have a more experienced operator come to their lab to assist them. The membership strongly believes this type of activity will allow us to be more competitive as we move to a “valued care” model. 

Dr. Mustapha: If you or one of your partners do not meet an 80% CTO crossing rate across the board, what should be done to improve the outcome and increase the CTO crossing success rate?

Dr. Ansel: Education and utilizing available resources is very important. It actually creates more camaraderie. The cases are less stressful as a result, and may even be fun. 

Dr. Mustapha: Do you believe the tibial CTO to be equal to SFA/popliteal CTO? 

Dr. Ansel: Yes and no. Tibial disease is often a different disease process compared to the SFA, though, in my experience, SFA CTOs can be typically crossed even when outside the vessel. Tibial disease, in my experience, is either very easy or very difficult, with not many in-between. Some long tibial CTOs are actually very easy, with the wire quickly traversing a lumen compressed from medial disease. Others are, however, much more difficult.  We do not have the same number of devices for tibial re-entry and once outside a calcified vessel, it can be almost impossible to get back into true lumen, which thus necessitates a more distal pedal puncture to come back retrograde.  

Dr. Mustapha: Can you share more about the VIVA CLI program and tell readers why they should not miss VIVA this year?

Dr. Ansel: The VIVA CLI program will once again continue to build upon the basics while at the same time, providing the latest techniques by the best operators in the world. We feel VIVA is the ultimate endovascular educational experience. The chance to work with our fantastic, multi-specialty faculty, including the VIVA partnership with our Leipzig Interventional Course (LINC) European colleagues, is an experience simply not to be missed. We also have continued the late-breaking trial momentum started over the last few years, so attendees will hear the latest and greatest data first at VIVA.

Disclosure: Dr. Mustapha reports he is a consultant for Bard, Covidien, Cordis, CSI, Spectranetics, Boston Scientific, Cook, & Terumo. Dr. Ansel reports he is a member of the medical advisory board for Boston Scientific, Medtronic, Cardinal Health, & Reflow Medical; he reports royalties for sheaths, balloons, & catheters with Cook Medical.

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

Dr. Gary Ansel can be contacted at gary.ansel@ohiohealth.com