Critical Limb Ischemia Management- Regenerative Care

Critical Limb Ischemia (CLI) is the most advanced stage of peripheral arterial disease (PAD) that significantly blocks blood flow in the lower limbs. CLI is a chronic condition that is associated with severe pain in toe or feet while resting. This increases the risk of heart complications. In extreme cases, the individuals require limb amputation.

CLI management focuses on the restoration of adequate blood flow in limbs. To undertake an effective therapeutic approach, you must understand Critical Limb Ischemia (CLI) and available treatment options.

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What Is Critical Limb Ischemia?

Chronic limb ischemia is referred to as end-stage PAD. It is characterized by multi-level atherosclerosis and plaque formation, leading to hindrance/blockage of blood in the lower limbs. The underlying pathophysiology of the disease is crucial in understanding its developing factors. This includes:

Macrovascular Obstruction: develops progressively, restricting blood flow to the lower limbs due to atherosclerosis.
Microvascular Obstruction: develops endothelial damage that leads to inadequate platelet activation, decreased blood fluidity, or leukocyte adhesion.
Paralysis of Vasomotor: Blood vessels undergo maximal dilation that gradually leads to arterioles paralysis. The response to metabolic changes gets compromised. Leads to resting pain.
Systemic Failure: the initial stage of CLI triggers angiogenesis (new blood vessel formation) and arteriogenesis (collateral vessel enlargement). This compromises nutritional flow and tissue oxygenation due to increased demand, resulting in tissue death.
Metabolic Shift: The compromised nutritional flow pushes tissue towards anaerobic metabolism. This is triggered by hypoxia, leading to tissue acidosis.

What are the Common Symptoms and Causes of CLI?

The symptoms and causes of CLI involve severe resting pain on lower extremities. The pain wakes an individual at night. Sometimes walking or putting legs on the edge of the bed and walking relieves the pain. Some other symptoms include:

Intense foot or leg pain at resting stage
Cold limbs (hand, feet, or legs)
Numbness in legs and feet
Slow healing of sores, skin discoloration
Experiencing a weaker pulse on lower limbs

Critical Limb Ischemia Criteria: How Is It Diagnosed?

Healthcare professionals diagnose CLI based on its symptoms. Some diagnostic tests and identification include:

Imaging: MRI, CT scans, Ultrasounds, or angiograms
Wound healing capability
Extend of narrowed arteries
Presence of non-healing ulcers or gangrenes

One of the important early diagnostic aspects involves Critical Limb Ischemia ABPI (Ankle-Brachial Pressure Index) measures. This is the ratio of systolic blood pressure between the ankle and the arm. The indicative range includes:

0.9-1.3- Normal
0.6-0.9- Mild PAD
0.3-0.6- Moderate/Severe PAD
0.3-0.4- CLI

However, in diabetic patients, the presence of calcified vessels makes the arteries incompressible. This can lead to a high ratio in Critical Limb Ischemia ABPI. In the case of such patients, the toe brachial index (TBI) shows more accuracy.

Critical Limb Ischemia ICD 10 & Critical Lower Limb Ischemia ICD 10

CLI is coded 170.2-series (atherosclerosis in native arteries of the extremities)

Code is given based on clinical presentations such as:

Rest Pain (e.g., I70.22-)
Ulceration (I70.23-)
Gangrene (I70.26-)

Hereby, the laterality matters depend on- Right leg, Left leg, Bilateral legs, Unspecified extremity [1]

Accurate ICD-10 coding plays a crucial role in precise diagnosis, risk factor assessment, and treatment planning.

What are Conventional Treatments for CLI?

The common treatment includes:

Palliative Care: includes medications that prevent clots, manage hyperglycemia, hypertension, and hyperlipidemia
Endovascular Procedures: This involves minimally invasive procedures such as angioplasty (placing a stent for opening blocked or thinned arteries), atherectomy (removing buildup of plaque)
Surgical Bypass: A surgical procedure that repairs and replaces arteries by using the patient’s own vein or a synthetic replacement

*In case the above treatment does not work, the affected body part gets amputated. Approximately 1 in 5 patients experience limb amputation in the case of CLI. This underscores the urgency in transitioning towards regenerative treatment options.

How Regenerative Therapies Work in CLI?

Scientists are working at the cutting edge using a stem cell-based regenerative approach for CLI. The use of stem cells for CLI patients has various therapeutic advantages. This includes:

Cellular Regeneration: Stem cells differentiate into endothelial cells, which help in new artery development
Tissue Repair: Stem cells interact with existing endothelial cells that promote cell growth and migration. This enables the formation of new arteries and prevents leaky vessels. This facilitates tissue repair and enhances wound healing.
Angiogenesis: Stem cells release various growth factors (VEGF, IL-8, FGF) that support angiogenesis. The production of growth-supporting enzymes increases (MMP2, MMP9, MT1-MMP)
Anti-Inflammation: Stem cells releases anti-inflammatory cytokines (PGF2, TSG6, IL8, sTNFR, CXCL5, or CXCL6)
Immunomodulation: Stem cells facilitate directed immune response by enhancing the role of M2 macrophages and regulatory T cells. This redirects immune cells towards repair mechanisms and promotes healing.

Clinical Evidence Supporting Regenerative Care

Preclinical and clinical trial research showed a positive outcome of using stem cells for CLI patients. This includes:

Angiogenesis: Improves the development of new blood vessels, improvement in blood flow and oxygenation in ischemic tissues [2]
Reduced Inflammation: Stem cells release anti-inflammatory cytokines that reduce inflammation. It also helps in the repair of the damaged tissues.
Repair of Existing Blood Vessels: Stem cells secrete certain growth factors that repair existing cells/tissue. It creates a healthier microenvironment that further enhances circulation and tissue regeneration.
Wound Healing: Stem cells improved wound healing mechanism, reduction of subsequent pain and limb salvage [3]

Who May Benefit from Regenerative Approaches?

Patients who are not eligible for surgery or revascularisation
Patients who experience refractory CLI, where patients experience persistent rest pain, severe ischemia, non-healing ulcers or gangrene
A diabetic patient with minimal ability for distal blood vessel reformation

Safety, Eligibility & Treatment Considerations

Stem cell therapy is observed as safe for CLI patients. Major criteria followed to ensure patients’ safety include:

Use of superior quality stem cells with high viability and physiological condition
Detailed patient health assessment to check eligibility
Administration of an optimised dose of stem cells
Continuous monitoring and supervision after the therapy

*Advancells, India, is one of the renowned stem cell research laboratories that works on chronic diseases, including CLI

Future Directions in Critical Limb Ischemia Management

Stem cell therapy potentially offers a promising solution for CLI. The future research must consider:

Large-scale clinical trial for ensuring long-term treatment effectiveness and safety
Development of a standardised protocol, cell source, and treatment procedure
Development of nanotechnology-based tissue scaffolds that promote cell survival, host vasculature, etc.

Patient Success Stories

References

ICD10Data.com. I70.22 Atherosclerosis of native arteries of extremities with rest pain. 2026. Available from: https://www.icd10data.com/ICD10CM/Codes/I00-I99/I70-I79/I70-/I70.22
Shirbaghaee Z, Heidari Keshel S, Rasouli M, Valizadeh M, Hashemi Nazari SS, Hassani M, Soleimani M. Report of a phase 1 clinical trial for safety assessment of human placental mesenchymal stem cells therapy in patients with critical limb ischemia (CLI). Stem Cell Research & Therapy. 2023 Jul 5;14(1):174.
Xie B, Luo H, Zhang Y, Wang Q, Zhou C, Xu D. Autologous stem cell therapy in critical limb ischemia: a meta‐analysis of randomised controlled trials. Stem Cells International. 2018;2018(1):7528464.

FAQ’s

Q- How is Critical Limb Ischemia Diagnosed?

CLI is diagnosed based on chronic rest pain, considering ABPI ratio, determination of toe pressure, and non-healing ulcers or gangrene.

Q- Can Stem Cell Therapy Prevent Limb Amputation in CLI Patients?

The research evidence and clinical trials reported have shown the ability of stem cell therapy in preventing limb amputation. They improve wound healing, blood flow in ischemic areas, and nutrient delivery. They facilitate tissue regeneration and repair of existing tissue.

Q- Is Stem Cell Therapy Safe for CLI Patients?

Yes, the current evidence ensured safety of stem cell therapy in CLI patients. Care is taken for the quality of stem cells and an adequate source of application.

Critical Limb Ischemia: Discover New Hope Through Regenerative Care

Urgency of Critical Limb Ischemia