CLI Hemodynamics for Diagnosis and Treatment

Disclosure: Dr. Mustapha reports he is a consultant for Bard, Covidien, Cordis, CSI, Spectranetics, Boston Scientific, Cook, and Terumo. Dr. Adams reports he is a consultant for Cook Medical, Daiichi Sankyo, Lake Region Medical, Volcano, Asahi, Abbott Vascular, CSI, Medtronic, and Terumo. He is a speaker for Abbott Vascular, CSI, Cook Medical, Medtronic, and Spectranetics. He has received research support from Boston Scientific, CloSys, Daiichi Sankyo, Flexible Stenting Solutions, Medtronic, Volcano, and Mercator. 

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

Critical limb ischemia (CLI) hemodynamics has been the cornerstone measure prior to CLI vascular revascularization. It has, and continues to be, a crucial step in the algorithm of therapy for the CLI patient. Today, the CLI patient adds a few conflicting factors into the assessment of their tibial-pedal arteries, including the concept of non-compressible arteries leading to falsely elevated ankle-brachial index (ABI), which has been studied to some degree. Many CLI specialists also began to see discordance between patients with CLI and toe-brachial index (TBI). This issue emerged during the era of infrapopliteal trials that used tibial-pedal hemodynamics as trial inclusion and exclusion criteria. Surprisingly, many patients met the clinical and angiographic findings of critical limb ischemia, but were excluded from the studies due to elevated hemodynamics.

This month, Dr. George Adams shares his experience and his personal interpretations of CLI hemodynamics in his daily practice.

J.A. Mustapha, MD: How many critical limb ischemia (CLI)-specific procedures do you perform per week?

George Adams, MD: I perform 10 CLI procedures per week.

J. Mustapha: What is your average time per CLI procedure?

G. Adams:  3 hours.

J. Mustapha: While evaluating your CLI patient, what are the must-have clinical findings for these patients to be considered “clinically positive” for CLI?

G. Adams: Rutherford class 4-6 defines CLI; specifically, patients with rest pain and/or non-healing wounds.

J. Mustapha: After completing clinical assessment of a CLI patient, what are your usual next steps?

G. Adams: Ankle-brachial index (ABI), toe-brachial index, and duplex ultrasound. I also evaluate the patient for cardiovascular and cerebrovascular disease, considering these two pathologies typically lead to their demise.  

J. Mustapha: What do you do with patients with elevated ABI?

G. Adams:  Duplex ultrasound.

J. Mustapha: If the toe-brachial index (TBI) and ankle/toe pressures are not conclusive (elevated instead), do you downgrade this patient to a non-CLI presentation? Or do you do any additional testing?

G. Adams: Typically, if the TBI and ankle/toe pressures are not conclusive, this means that the pedal vessels are calcified. The next step for me would be an angiogram considering the patient has CLI.

J. Mustapha: If the ABI was falsely elevated, do you repeat post-revascularization and during the follow-up periods?

G. Adams: We typically follow with duplex ultrasound post intervention if the ABI is falsely elevated.

J. Mustapha: What about the TBI/ankle and toe pressures?

G. Adams:  If the TBIs are falsely elevated, we will follow toe pressures.

J. Mustapha: Transcutaneous oxygen (TCO2) measurements can be helpful. Do you believe we have been using these tools sufficiently?

G. Adams:  No, because the majority of our patients have difficulty lying still for an extended period of time to get an accurate TCO2 measurement. Also, we don’t see the oxygenation measurement utilization used as much as we would like, primarily due to lack of awareness and the misconception that the test is not helpful. We hope to see more utilization of transcutaneous oxygen measurements.  TCO2 is a helpful test, especially when combined with the more widely used toe pressures. Toe pressure is a standard of care in many labs across the country.

J. Mustapha: What do you do for the non-diabetes mellitus patient that has a foot ulcer and normal hemodynamics?

G. Adams:  We work up the patient for other causes other than arterial — for example, a venous etiology.

J. Mustapha: When should we assume an ulcer is neuropathic?

G. Adams: Considering diabetes is an epidemic in the United States, neuropathic ulcers are common. However, the majority of these ulcers may be mixed in nature. For example, neuropathic ulcers may actually be neuro-ischemic, meaning they also have an arterial component. Therefore, the ulcer may heal if we are able to improve blood supply to the wound. 

J. Mustapha: Do you believe in angiosome-directed therapy?

G. Adams: Yes. Remember that it is not just getting blood flow to a wound, but it is also direct in-line flow to the wound to improve perfusion pressure.

J. Mustapha: Does the angiogram of a CLI patient differ from the angiogram of a claudicant patient? 

G. Adams: Yes, the typical CLI patient is older, diabetic, and with renal insufficiency. As such, the CLI patient suffers from multilevel peripheral arterial disease, chronic total occlusions, and plaques that are calcified. These CLI lesions are definitely the most challenging as compared to a claudicant.

J. Mustapha: What is your favorite access for a long popliteal-tibial chronic total occlusion (CTO)?

G. Adams: A combination: antegrade common femoral artery and retrograde tibial.

J. Mustapha: What are your favorite 3 wires for tibial CTO crossing?

G. Adams: The 18gm 0.14-inch coil-tipped Approach CTO (Cook), Victory 18gm 0.14-inch polymer coated wire (Boston Scientific), and Astato 30gm 0.18-inch coil-tipped wire (Asahi Intecc).

J. Mustapha: What are your favorite supporting catheters for superficial femoral artery (SFA)/popliteal CTO crossing?

G. Adams: Quick-Cross (Spectranetics), Corsair (Asahi Intecc), Navicross (Terumo) from antegrade, and retrograde would be the CXC (Cook) because it can go through a 2.9 French sheath.

J. Mustapha: Do you use atherectomy during CLI therapy?

G. Adams: Absolutely.

J. Mustapha: Is there one atherectomy that fits all for CLI therapy?

G. Adams: No. The plaque, length of the lesion, subintimal versus true lumen crossing, and location of the lesions will help determine which atherectomy device to select. Selecting an atherectomy device, as with all tools in the periphery, is individual to the operator.

J. Mustapha: Is there any role for combining atherectomy and drug-coated balloons? 

G. Adams: Yes, there is a thought that if a calcified plaque can be modified, that drug uptake to the media and adventitia by drug-coated balloon may be improved. This thought is supported by a 2012 study by Stabile et al.¹

J. Mustapha: What is the best scenario for an atherectomy/drug-coated balloon combination?

G. Adams: A patient who is at a high restenosis rate (older, diabetic, renal insufficiency) with CLI whose stenotic lesions are calcific in nature.

J. Mustapha: What advice do you have for the CLI therapist out there?

G. Adams: To treat CLI successfully, you need three things:

1) Tools. A carpenter is only as good as his tools.

2) Patience. These are long and complicated cases; it’s a marathon, not a sprint.

3) Skill. You must be a lifelong learner, because this is one of the fastest-evolving fields today. 

Case Study

A 72-year-old diabetic male with a two-week history of a non-healing ulcer of the left hallux presented with severe rest pain. Non-invasive evaluation showed non-palpable left dorsalis pedis and posterior tibial pulses. Both were biphasic via Doppler exam. Left ankle brachial index (ABI) = 1.4 and left toe brachial index (TBI) = 0.93. Per current critical limb ischemia (CLI) endovascular trials, this patient would be excluded due to hemodynamics. 

At one-month follow up, the patient reported resolution of rest pain and wound healing was observed. 

Case performed by J.A. Mustapha, MD

Reference

1. Stabile E, Virga V, Salemme L, Cioppa A, Ambrosini V, Sorropago G, et al. Drug-eluting balloon for treatment of superficial femoral artery in-stent restenosis. J Am Coll Cardiol. 2012 Oct 30; 60(18): 1739-1742. doi: 10.1016/j.jacc.2012.07.033.