Critical Limb Ischemia: What to Know

As the number of people suffering from atherosclerosis-related conditions such as  diabetes and heart disease grows, so do cases of a serious, potentially deadly condition called critical limb ischemia (CLI). 

Limb ischemia is characterized by severe pain in your legs and feet while at rest, ulcers and gangrene. It can progress rapidly if not treated, resulting in mandatory amputation and possibly death. 

What Is Critical Limb Ischemia? 

Critical limb ischemia is the most advanced form of peripheral artery disease (PAD), a progressive circulation disorder caused by the buildup of plaque or blockage in the arteries. 

It can form in any artery, but when it reaches advanced levels in the legs and feet it is called critical limb ischemia. Swift care is required to restore blood flow to prevent severe infection and limb loss. 

Because critical limb ischemia is rooted in peripheral artery disease, they share many of the same risk factors: 

●      Age, men over 60 and post-menopausal women are at increased risk

●      Smoking

●      Diabetes

●      Obesity

●      Sedentary lifestyle

●      High cholesterol

●      High blood pressure

●      Family history of atherosclerosis or claudication (cramping and muscle weakness)

CLI can also be caused by trauma, embolisms, blood clots or any injury to a muscle that severely limits blood flow. 

The “5 Ps” of Critical Limb Ischemia

CLI’s spectrum of symptoms is often categorized as the “5 Ps of arterial ischemia,” which can help identify its progression, from moderate to irreversible: 

●      Pain or cramping which increases at rest

●      Pallor of the skin - ranging from shiny, smooth and dry to pale and mottled

●      Pulselessness - an absent or diminished pulse in the legs or feet

●      Paresthesia - numbness or tingling that can progress to paralysis

●      Poikilothermia - a coolness of the skin

As ischemia advances, acute symptoms include:

●      Open sores, skin infections or ulcers that do not heal

●      Dry gangrene (dry, black skin) of the toes or the entire foot. 

Critical – or chronic – limb ischemia is defined as having symptoms that develop over more than two weeks. Acute limb ischemia is characterized by symptoms that progress more rapidly (under two weeks). Both require immediate care, but that is particularly true with acute limb ischemia, where the limb may have only hours before it becomes unsalvageable. 

Early Diagnosis Is Crucial 

At the onset of CLI, it’s easy for symptoms to be discounted or attributed to another issue, as many conditions can share symptoms such as numbness or cramping. 

But for patients with a medical history that includes any form of arterial damage or coronary heart disease, additional physical exams and screenings are highly recommended to rule out blockage. These procedures include: 

●      Manual examination of the feet and legs to assess skin temperature, sensitivity to touch and pulse levels.

●      An Ankle-Brachial Index (ABI) test to compare blood pressure in your limbs.

●      Doppler ultrasound which uses high-frequency sound waves to measure blood flow rate in the veins.

●      Computerized tomography (CT) angiography which combines a CT scan with dye injection to create an image of affected blood vessels.

●      Magnetic resonance angiography (MRA) which uses a strong magnetic field, radio waves and a computer to evaluate blood vessels. 

Treatment Options 

Depending on how quickly CLI is diagnosed, there are treatment options which can open blocked arteries or create a bypass. Depending on the severity and extent of the disease, these include:

•  Endovascular treatments, including catheter-based techniques, are usually the first choice to determine the extent of the disease. These treatments can help doctors plan additional measures, with balloons, stents and other devices.

• For acute limb ischemia, doctors can use catheter-directed thrombolysis (CDT) – a non-surgical procedure that dissolves blood clots – or mechanical thrombectomy. If the clot is extensive, an open thromboembolectomy procedure may be used to surgically remove the blood clot.

• Surgical treatments like bypass surgery, which employs a graft to go around the damaged or blocked blood vessel, can also be used if the disease is far more advanced. 

Unfortunately, once limb ischemia has reached irreversible levels, the only solution to avoid further health complications (including death) is amputation. 

Should you fall into one of the risk categories, speak to your primary care physician or cardiologist about additional testing. Early detection, combined with moderate exercise, healthy diet and quitting smoking can make the difference between life or limb.