Critical limb ischemia (CLI) therapy is experiencing immense growth and it is reflected among all specialties. Most of the growth is in the form of endovascular therapies. Despite this vast growth in therapy, the outcome and results are not all equal and satisfactory. Some sites or centers are beginning to show that they are carving out a successful edge over others, leading to the introduction of new terms such as “CLI Center,” “Amputation Prevention Program,” etc. Historically in medicine we see disparate results when fast growth such as this is experienced. Fast growth can quickly lead to vast success or quick failure.
What to do with such differential outcomes? Do we just let the current course of therapy play itself out, or do we step forward and state the obvious for the betterment of all patients and their providers? This month, we have the privilege of hearing the opinion of an expert, John Rundback, MD, who has been leading the CLI field with great success.
J.A. Mustapha, MD: John, endovascular therapy has risen exponentially over the last few years. What is your first thought on this rise in endovascular therapy?
John Rundback, MD: There are several reasons why endovascular therapies are growing. The first and principal factor is an aging population with high prevalence of diabetes, metabolic syndrome, obesity, and chronic kidney disease, all of which are associated risk factors for peripheral arterial disease (PAD). A second reason is increased awareness, particularly amongst podiatrists who now are better equipped to recognize and refer patients with ischemic injuries to the foot and ankle. Related is a growing prevalence of CLI, which used to affect 2-5% of the PAD population, but now affects almost 10% of patients with PAD over the age of 70. The third reason, which I believe to be crucial, is our ability as endovascular therapists to successfully treat more and more complicated patterns of disease, with supportive data regarding clinical benefit. Sophisticated techniques and the endovascular devices needed to perform them — such as advanced tibial intervention, multilevel therapies, atherectomy, drug delivery technologies, pedal access, and plantar pedal loop angioplasty, to name a few — have all served to change the paradigm for endovascular therapy from a treatment that had limited value to one that can reliably save limbs and lives.
J.A. Mustapha, MD: There seems no slowing down of endovascular procedures as new operators embark on expanding therapy to include CLI. Most of the new operators tend to train on the job, and by trial and error. Is there anything that can be done to provide better training to newcomers to achieve the skill level of experienced CLI operators?
John Rundback, MD: I am very concerned about interventionalists initiating a CLI program without adequate training and backup. This may be acceptable in environments in which there is nobody else doing this work, since the unmet need must be filled. However, even in that situation, there should be a gradual evolution of treatment experience, with the goal of assuring successful therapy and not overextending in a way that might be harmful. It is much more prudent to treat what can be comfortably treated and then perform secondary interventions if needed. That being said, CLI interventions can be extremely challenging, both on a cognitive and a technical level. When appropriate, physicians should defer the most complex interventions to individuals in their community who have the most experience doing these cases, regardless of specialty, and work collegially to support this referral pattern. Over time, simply due to the nature and prevalence of CLI, there will be sufficient need and comfort to provide increasingly complex services that would have been referred away. The key here is that less experienced CLI operators need to at least initially suppress their natural tendencies to be very aggressive, and instead think of who will provide the best care for the patient. Companion to this is the idea that doctors should not be threatened to refer very difficult cases to other interventionalists, rather than abandoning care and dooming a patient to limb loss. Perhaps the best way to accomplish all of this and maintain a spirit of collaboration is to work closely to establish CLI teams, which include not just endovascular therapists, but podiatrists, wound care specialists, infectious disease doctors, and others who have an interest in these patients. Really interesting data from Italy1-3 has shown that growing a CLI practice organically and safely through the creation of CLI teams not only provides the best outcomes, but also is associated with higher volumes of endovascular treatments as patients and referring physicians understand and trust the CLI team results.
J.A. Mustapha, MD: CLI is a term loosely used to describe many forms of PAD. Is it time to have a universally agreed-upon definition of the term?
John Rundback, MD: CLI has generally referred to patients with ischemic rest pain or tissue loss, and I think this is largely still a reasonable definition. Over the next few years, we will probably add validated perfusion measures to enhance the term “CLI”, whether this is using existing technologies such as skin perfusion pressure (SPP), transcutaneous oxygen pressure (TcPO2) or immunofluorescent angiography, or emerging tools including near-infrared imaging. However, what does need further definition and detail is an understanding of the patterns of CLI and how this relates to limb preservation, particularly after intervention. The Wound, Ischemia, and foot Infection (WIfI) criteria from the Society for Vascular Surgery (SVS) is an important first step in this direction, but overlooks angiographic descriptors that are crucial to outcome. There are no validated risk stratification models for CLI, so that it is very difficult to objectively judge outcomes based upon degree of complexity and overall patient condition. In addition, I really believe that we need to create a system of reporting CLI interventions not only based on our ability to restore complete or partial unobstructed flow towards the feet, but also based upon the status of the pedal loop, robustness of collaterals, details of the wound blush, and intraprocedural perfusion assessments. There is a great deal that we are just beginning to understand with regard to what potentially constitutes optimal revascularization in these patients.
J.A. Mustapha, MD: As you know, many different specialties require accreditation and CME. Are we there yet for the CLI provider?
John Rundback, MD: We need to think of CLI care and interventions differently than interventions in other vascular beds, and the skill set needed for treating these patients is more sophisticated. Credentialing and accreditation for CLI physicians should be an ongoing process of training and review, with better definitions and risk-stratified public reporting of outcomes by individual practitioners and institutions. An informed patient population will mandate all physicians involved in the care of CLI patients to adhere to the highest possible standards. I believe that in the next several years, we will see an evolution of societies and organizations pressing for increased rigor in how we train and evaluate limb salvage techniques and CLI teams.
J.A. Mustapha, MD: What about CLI program accreditation?
John Rundback, MD: Integral to the idea of best CLI care is the creation of CLI teams, and inherent in this is the concept of CLI Centers of Excellence. Not everybody will be able to provide the same quality of care, and this needs to be monitored. We will of course need societal, industry, and institutional support to move in this direction initially, and validation that these dedicated programs provide higher levels of excellence in care. An important metric of the success of CLI programs will be the financial benefit not only in terms of acute care, but in longer term societal costs. Unfortunately, in today’s economic climate, the barriers to implementing these specialized CLI programs on a broad scale is such that I am not sanguine that this can be achieved in the near future, but I do think we will see the emergence of some pilot CLI Centers of Excellence within the next decade.
J.A. Mustapha, MD: Please share with us some pre and post images of some of your greatest CLI successes.
John Rundback, MD: [Figures 1-6] This was a recent 76-year-old woman with ischemic ulceration and rest pain involving the plantar aspect of her forefoot medially, particularly affecting the bases of the first and second metatarsals. She had a recent aortic valve replacement and her anticoagulation could not be discontinued, and her INR was 2.9 at the time of the procedure. Intervention was performed entirely via a dorsalis pedis access, with retrograde subintimal recanalization and angioplasty of the anterior tibial artery, followed by advancement across the anterior tibial arch down the tibioperoneal trunk to intraluminal and subintimal recanalization and angioplasty of the entire length of the posterior tibial artery, through to the plantar branches. The patient had complete healing of her ulceration and resolution of rest pain within 3 weeks of the procedure. This is an example of the ability of advanced techniques to allow successful revascularization and clinical outcomes even in the most challenging cases.
- Scatena A, Petruzzi P, Ferrari M, Rizzo L, Cicorelli A, Berchiolli R, et al. Outcomes of three years of teamwork on critical limb ischemia in patients with diabetes and foot lesions. Int J Low Extrem Wounds. 2012 Jun; 11(2): 113-119. doi: 10.1177/1534734612448384.
- Clerici G, Faglia E. Saving the limb in diabetic patients with ischemic foot lesions complicated by acute infection. Int J Low Extrem Wounds. 2014 Dec; 13(4): 273-293. doi: 10.1177/1534734614549416.
- Setacci C, Galzerano G, Sirignano P, Mazzitelli G, Sauro L, de Donato G, et al. The role of hybrid procedures in the treatment of critical limb ischemia. J Cardiovasc Surg (Torino). 2013 Dec; 54(6): 729-736.