Critical Limb Ischemia (CLI) is a condition where there is severe blockage in the blood vessels thus reducing blood flow or oxygen supply to hands, feet and legs. It is the most severe pattern of peripheral arterial disease. Peripheral arterial disease is a common circulatory problem where the narrow arteries reduce blood flow to the limbs and extremities. PAD is caused by the hardening and narrowing of the blood vessels due to the build-up of fatty deposits or plaques.
There are several complications associated with CLI such as major amputation, cardiovascular events and death. Many specialists report a mortality rate of 20% within 6 months after the diagnosis and 50% at 5 years. This excessive mortality may be due to the systemic cardiovascular diseases, including coronary artery disease and cerebrovascular arterial disease. Furthermore, CLI comes with a slew of peripheral complications such as ulceration, gangrene, infection and a high risk of lower limb amputation estimated in 10%–40% of patients at 6 months, especially in non-treatable patients
In an interview with Times of India, Dr. Balaji V, Senior Consultant Vascular Surgeon at the Apollo Hospitals Greams Lane, Chennai delves more into the various unknown aspects about CLI. He says that one of the key symptoms of CLI is extreme pain in the limbs. This occurs because of severely decreased blood flow to the limbs and the pain worsens at night when lying down. The lesser blood flow also diminishes the pulse in the legs making it difficult to heal superficial or deep foot injuries. Ulcers, sores and gangrene also occur.
Diagnosis of CLI involves many steps. The initial approach requires identifying cardiovascular risk factors and evaluating peripheral pulses (femoral, popliteal, dorsalis pedis and posterior tibial artery) even if their presence cannot exclude completely a potential condition of ischemia. Among the first-level examinations, the specialists look for ABI (ankle brachial index), TBI (toe brachial index), TcPO2 (transcutaneous oxygen pressure) and ultrasound (US) colour duplex. The second-level examinations include magnetic resonance imaging (MRI) and computed tomography (CT) which help to detect arterial lesions.
Risk factors for CLI include old age, smoking, high cholesterol levels, chronic kidney disease, hypertension and diabetes. However these factors can be easily tackled with strategic and timely care. Quitting smoking even after CLI onset lowers the chances of leg amputation. Dr. Balaji suggests that patients with CLI should be treated with statin medications to reduce risk of heart attack and amputation. Controlling blood sugar levels may also help decrease the risk of amputation and improve wound healing.
Management of CLI is a complicated process and it has to be personalised according to the disease severity in the patients. However, the main priority of the doctors should be to preserve the limb and leg function. “Medication can help control disease progression, reduce pain, prevent clotting, and fight infections,” says Dr. Balaji. Restoring blood flow to the affected leg by surgical bypass or angioplasty (revascularisation) can help heal wounds.
Dr. Balaji even discussed some novel therapeutic solutions for CLI such as stem cell therapy. Cell-based therapies have emerged as a new therapeutic alternative for CLI. Stem cells have great potential for evolving into various cell types. The surrounding cellular environment gradually stimulates the stem cells, resulting in the formation of specialised cells that are identical to those with which they come in contact with. Hence, neoangiogenesis ensures the development of new small blood vessels, thereby restoring blood circulation and enabling reparative activities.
Stem cell therapies can be allogeneic or autologous. While autologous treatments use stem cells harvested from the patient, allogeneic treatment uses stem cells from healthy donors. The specialist gives an intramuscular injection to the muscle bulk of the affected limb of the patient. Stem cell therapy helps decrease pain in the limb, improves walking and enhances quality of life. This therapy is a strong alternative to amputation.
Both gene- and cell-based therapies in CLI are encouraging options for the potential treatment in a subset of patients. However, all of these studies need more double-blinded control studies and the evaluation of longer outcomes in terms of wound healing, amputation, safety and quality of life.