Peripheral artery disease (PAD) is a medical condition in which the arteries other than those which supplies blood and oxygen to the heart and brain narrow down. It generally affects the limbs. Critical Limb Ischemia (CLI), commonly known as limb threat, is the advanced and severe stage of Peripheral artery disease and needs treatment by a vascular specialist or surgeon. Critical Limb Ischemia (CLI) is a chronic disease which includes pain in the limbs including the toes because of occurrence of ischemia (a slowdown of the cellular metabolism because of the restricted supply of blood through the arteries), along with arterial ulcers and gangrene. This pain which is also known as rest pain, affects the legs and can temporarily be relieved by raising the leg while resting with the help of pillow or by walking around.
The ache can become excruciating and severe if treatment is delayed. Critical limb ischemia, in general, has a negative prognosis within a year of the initial diagnosis. The amputation rates are approximately 12 percent within the first year and possibility of the patient succumbing to the disease is 50 percent and 70 percent in the next 5 and 10 years respectively. Every year around 500 to 1000 new cases occur per 1 million, with diabetes being the biggest risk factor.
Types of Critical Limb Ischemia
Critical Limb Ischemia can be divided in to two types, namely rest and tissue loss.
- Rest Pain: It is the continuous burning pain of the lower leg or the feet. The pain can be relieved by sitting or standing.
- Tissue Loss: The second type is tissue loss where development of the ulcers and gangrene is predominantly caused by the non-supply of blood in some parts of the limbs.
Symptoms of Critical Limb Ischemia
As mentioned, critical limb ischemia is the aggravated stage of Peripheral Arterial Disease, where only 1 in 5 people who show symptoms of Peripheral Arterial Disease develop critical limb ischemia. It's very important that the affected person is reviewed by a team of specialists who are proficient in treating patients with blood circulation problems. An early detection of critical limb ischemia can be done if the following symptoms are visible in someone and is complaining of severe pain in the limbs or occurrence of non-healing sores on the feet or legs:
- Numbness in the feet
- Skin of the legs or feet turning dry
- Toenails thickening
- Reduction of temperature in the area of feet and legs
- No or faint pulse in the feet or legs
- Non-healing sores, skin infections or ulcers
- Skin turning black and senseless.
Causes of Critical Limb Ischemia
As the narrowing of the vessels increase, the person gets affected by critical limb ischemia since the blood flow is not able to meet the metabolic demands of tissues. The causes of critical limb ischemia are mostly leading an unhealthy lifestyle which includes someone who is obese, has poor diabetes or high blood pressure control and a family history of vascular disease. In Critical Limb Ischemia, the walls of the arteries get thickened caused by the build-up of plaque, commonly known as atherosclerosis which reduces or stops the blood flow to reach the limbs thus reducing the blood circulation to the feet, legs and hands.
Risk Factors of Critical Limb Ischemia
The risk factors for Critical Limb Ischemia which increase the chances of someone getting affected by critical limb ischemia include:
- Men of age more than 60
- Women who have attained menopause
- Smoking and Drinking
- High Blood Sugar (Diabetes)
- Excessive eating or unhealthy eating habits
- High cholesterol levels (hypercholesterolemia)
- Sedentary lifestyle that calls for nil physical activity
- High Blood Pressure (hypertension)
- Inheritance of vascular disease.
Along with the above cases, there are a number of other diseases that might result into critical limb ischemia. Buerger's disease, commonly known as thromboangiitis obliterans can cause critical limb ischemia. Thromboangiitis Obliterans is a recurring progressive inflammation of the small and medium arteries of the hands and legs. A few forms of arteritis can also cause critical limb ischemia.
Diagnosis of Critical Limb Ischemia
The criteria for the diagnosis of critical limb ischemia include either one of the following:
- Recurrent Foot Pain: If the patient has been complaining about recurrent foot pain for the past 2 weeks, has been taking analgesics dosage which did not subside the problem, has an ankle systolic pressure of 50mm Hg or less, or a 30 mm Hg or less toe systolic pressure, it could indicate the problem of critical limb ischemia.
- Non-Healing Sore or Gangrene: A non-healing wound or open sore or gangrene on the foot or toes shows that the blood flow through the arteries have been restricted or blocked and hence, the tissues are not able to get enough amount of oxygen.
- Auscultation: A "whooshing" sound in the arteries of the legs is heard by using a stethoscope.
Consulting a doctor is very important if any of the major symptoms are observed in anyone. An early detection of CLI can help the patient do a quick recovery and get back to normal life. The diagnostic tests for identifying and locating the cause of critical limb ischemia include:
- Ankle-Brachial Index (ABI): This is done by calculating the ratio of blood pressure at the ankle to the pressure at the ankle. A lower blood pressure at the ankle indicates towards the disease.
- Doppler Ultrasound: This Ultrasound can measure the velocity as well as the direction of the blood flowing through the vessels.
- CT Angiography: A hi-tech X-ray procedure that generates 3D images using a computer.
- Magnetic Resonance Angiography (MR angiography): Under the influence of strong magnetic field, the patient is exposed to radio waves. A computer measures the energy released in order to construct 2D and 3D images of the vessels.
- Angiogram: X-ray study of the vessels is taken with the help of contrast dyes.
Treatment of Critical Limb Ischemia
Critical limb ischemia is an extremely serious medical condition which needs immediate attention and treatment to re-establish the blood flow through the vessels to the affected area or areas. Most of the patients diagnosed with the disease have multiple arterial blockages.
Treatment for Critical Limb Ischemia is complex, depends on the patient's condition and also varies from patient to patient. However, the overall goal remains to decrease the pain and increase the blood flow. Treatments for critical limb ischemia can be done in the following ways:
- Medications for Critical Limb Ischemia: Doctors prescribe medications to prevent the further worsening of the disease by reducing the effects of the high risk factors like high blood pressure, hypercholesterolemia and high sugar. Medications that prevent the clotting of blood, which subsequently form ulcers and gangrene if not treated, are prescribed along with painkillers to reduce the pain of the limbs due to critical limb ischemia. For the pain, patients might be offered pain relief medicines like paracetamol or either weak or strong opioids, depending on the severity of the pain. Patients who take strong opioids often face problems like constipation and nausea, so along with these some laxatives and anti-sickness medication is also provided.
- Endovascular Treatments to Cure Critical Limb Ischemia: Such types of curing procedures are the least invasive and are often an option for the treatment of critical limb ischemia. The recommended treatment depends on the severity and location of the blockages. Most patients affected by critical limb ischemia have arterial blockages at many places. The method involves insertion of a catheterin the artery of the groin in order to gain access to the affected portion. Following are the few Endovascular treatments used by the doctors:
- Angioplasty: Angioplasty is done to open the blockages by inserting small balloons into an artery using a catheter. The balloon is inflated in there and as it inflates, the artery stretches and opens up thus, improving the blood flow. If required, a metallic device known as "stent" is then inserted to maintain the expanded the artery.
- Laser Atherectomy: Laser Atherectomy involves small pieces of plaque being vaporized with the help of the tip of a laser probe.
- Directional Atherectomy: In this method, a catheter with a rotating cutting blade removes the plaque from the artery physically.
- Arterial Surgery as a Treatment for Critical Limb Ischemia: If the endovascular therapy is not favorable for the arterial blockages, then surgery is recommended. This process involves the bypassing of the arterial disease with either a vein taken from other body parts from the patient or a synthetic graft.
- Amputation for Critical Limb Ischemia: The last option for treating Critical Limb Ischemia would be the amputation of a part of leg or feet. In some patients, the blood flow can't be re-established and amputation becomes the only option to cut off the gangrene or reduce the severe pain. Amputation reduces the risk of spreading the gangrene to the other parts of the body. It is recommended that amputation above the ankle should only be considered if it is the last option and all the other ways and treatments have been applied and failed.
Critical Limb Ischemia when detected early can be cured without any impact in the future. The treatment depends on the severity and many individual parameters. Whenever someone develops ulcers, or has pain in the legs or feet while walking or resting should see a vascular specialist or surgeon as early as possible. The earlier the diagnosis can be done, the earlier treatment can be initiated without any serious consequence.