CLI PERSPECTIVES

CLI and Low-Profile Devices: Have We Reached a Device Paradigm Shift?

July 9, 2016
Authors: 

CLI Perspectives is headed by section editor J.A. Mustapha, MD, Metro Health Hospital, Wyoming, Michigan. 

This month, Dr. Mustapha interviews Osamu Iida, MD, Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan.

Critical limb ischemia (CLI) is often thought of as tibial-pedal disease and is always associated with small vessel disease. This is for many reasons, including the comorbidities of CLI such as diabetes, chronic kidney disease, etc. With this interview, I am hopeful we can open the concept of CLI into its broad and original anatomical description of a multi-level and multi-vessel disease. It is true many of CLI patients have tibial-pedal disease, but also we need to mention and discuss the presence of inflow disease as well. Osamu Iida, MD, is an interventional cardiologist and a passionate CLI therapist from Kansai Rosai Hospital in Hyogo, Japan. Dr. Iida practices multiple approaches to treating CLI patients. One such approach is to provide direct flow to the target ischemic ulcers. This concept of direct flow to a target vessel forces operators to target one of the three tibial arteries. As we all know, it is not always easy to get to the target vessel from above alone, hence the need for alternative access approaches and small devices for the already diseased target access segment.

J.A. Mustapha, MD: Dr. Iida, please define CLI disease in the way you think of it daily, as you plan your treatment approach.

Osamu Iida, MD: The definition of CLI varies, but a case with a wound/ulcer caused by ischemia is definitely CLI. In such a case, revascularization should always be considered. The case may have a higher ankle-brachial index (ABI), transcutaneous oxygen (TcPO2), and skin perfusion pressure (SPP) values than the boundary values if lesions are present. This is because the amount of blood flow needed differs depending on the level of wound severity. In Japan, SPP is generally used for the evaluation of the wound, which is considered ischemic if under 40 mmHg.

Dr. Mustapha: Do you see value in low-profile devices in your daily CLI therapy or in selected cases only?

Dr. Iida: The answer is clearly “yes”. Approximately half of patients with CLI in Japan are on dialysis therapy. Lesions in below-the-knee and ankle arteries are commonly complicated, with an extremely tiny vessel diameter, as well as the presence of severe calcification. In order to prevent access complications, a 3 French (Fr) sheath is routinely used with an antegrade approach. Within these characteristics, it is commonly agreed that there is no chance to achieve satisfactory initial and midterm results without low-profile devices.

Dr. Mustapha: How have low-profile device changed your treatment plan to patients that you may not have treated in the past? 

Dr. Iida: Low-profile devices have enabled us to have similar efficacy with lower invasiveness. These devices are applied to treat small vessel lesions, as well as for distal access, including the tibial and digital arteries. Additionally, low-profile devices can reduce device cost, procedural time, and complication rates.

Dr. Mustapha: Share with us some of the latest low-profile devices to come to the market in Japan.

Dr. Iida: The latest such devices to become available to us are micro catheters, .010-inch or .014-inch wires, and 3 Fr sheaths. I believe micro-catheters by Asahi Intecc have superior trackability.

Dr. Mustapha: Have you seen an increase in CLI therapy in Japan, including multiple attempts to some of the previously failed revascularization procedures?

Dr. Iida: Traditional methods such as sympathetic nerve block and/or hyperbaric oxygen therapy are used for cases after failed revascularization. In fact, recently, we treated a case of ischemic ulcer caused by non-arteriosclerosis, where complete ulcer healing was obtained by the use of a sympathetic nerve block. 

Dr. Mustapha: Why do you think more operators are re-attempting revascularization of complex CLI cases after the initial failure vs the previous next step of major amputation?

Dr. Iida: It is a known fact that life expectancy after amputation is extremely poor. Operators are eager to prevent amputation; therefore, they will re-attempt. Although a first case may be unsuccessful, especially in cases of below-the-knee (BTK) lesions, sometimes recanalization can be achieved by incorporating tibial access techniques. Today, we can use many more techniques or approaches, than ever before, for lower extremity endovascular treatment to achieve higher initial success.

Dr. Mustapha: Do you think the low-profile devices are creating a device paradigm shift in the way we treat CLI vs what we were able to do a few years ago? 

Dr. Iida: I think a paradigm shift is difficult to identify as a result of the emergence of low-profile devices. A paradigm shift could occur after drug-eluting devices take over the use of plain balloons. Overcoming restenosis is the most important issue in CLI treatment.

Dr. Mustapha: Do you see lower complication rates with low-profile devices?

Dr. Iida: Yes, low-profile devices enable downsizing of sheaths and thus decrease the complication rate.

Dr. Mustapha: Please share with us how you currently revascularize complex CLI chronic total occlusions (CTOs) that have a proximal CTO cap in the superficial femoral artery (SFA) and distal reconstitution in the mid-tibial arteries?

Dr. Iida: I recently treated a patient in Rutherford Class 5, without infection, due to a long occlusion from the SFA ostium to the distal posterior tibial artery. I consulted with a vascular surgeon, but decided to perform endovascular treatment since an autologous vein graft is smaller than 3 mm and not appropriate for distal bypass treatment. I successfully crossed the lesion using the knuckle-wire technique and finished with balloon angioplasty alone, and achieved successful revascularization.

Dr. Mustapha: How do you ensure direct revascularization in most of your CLI cases?

Dr. Iida: I typically combine the use of tibial access techiniques to ensure direct revascularization.

Most vessels with long CTO lesions result in wounds. Therefore, a bi-directional approach with tibial access technique is definitely needed for higher initial success.

Dr. Mustapha: If direct revascularization is not successful, what is your typical “Plan B?” 

Dr. Iida: Plan B is stenting of the tibio-peroneal trunk and restoring the peroneal artery. The recoil rate is 97% at 15 minutes after plain balloon angioplasty in the infrapopliteal artery. The wound needs a definite amount of blood flow initially and at mid term. Therefore, after we revascularize, we incorporate the use of a stent to prevent residual stenosis and recoiling. This approach contributes to vessel patency and moderate blood flow maintenance to achieve wound healing in the long term. 

Disclosure: Dr. Mustapha and Dr. Iida report no conflicts of interest regarding the content herein.

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

Dr. Osamu Iida can be contacted at iida.osa@gmail.com.