Acute Limb Ischemia

Acute limb ischemia (ALI) means there’s a sudden and severe drop in blood flow to a limb, typically your leg or foot. This is usually due to a blood clot that forms in an artery and blocks blood flow. When this happens, the tissues in that area quickly become damaged and may soon die. You need immediate treatment to save your limb and your life.

ALI is an advanced stage of peripheral artery disease (PAD). About 1 to 2 out of every 100 people with PAD develop ALI. But people without PAD can also develop ALI if they have a condition that raises the risk of blood clots in their leg arteries.

Symptoms of acute limb ischemia

ALI causes a group of symptoms known as the “six Ps.” Your affected limb may feel:

• Painful: Severe pain is a common symptom and usually the first.
• Pale: Your skin looks much paler than usual.
• Pretty cold: Your skin feels cool to the touch.
• Pulseless: Your pulse is weak, or you can’t feel it at all.
• Pins and needles: You have a “pins and needles” feeling known as paresthesia.
• Paralyzed: You can’t feel or move your limb.

Call 911 or your local emergency number if you have symptoms of acute limb ischemia.

The longer your limb goes without blood flow, the worse your symptoms will get. Permanent damage to your limb may occur within four to six hours, and if it does, you may need an amputation. Don’t delay seeking medical attention.

ALI causes

There are three major causes of acute limb ischemia:

• Thrombus (blood clot that forms in your artery)
• Embolus (blood clot that travels to your artery from another spot)
• Direct injury to a blood vessel wall

A blood clot (thrombus) that blocks an artery causes most cases of acute limb ischemia. A thrombus is like an object that clogs a pipe. Blood can’t flow through to nourish your tissues, just like water can’t flow through a clogged pipe.

Usually, these clots develop in your leg arteries. A clot may form in a spot where there’s lots of plaque buildup. Or it may form on a stent or graft that providers previously inserted to treat PAD.

A clot may also form in one part of your body and then travel through your bloodstream. This is called an embolus. An embolus can get stuck in one of your arteries and block blood flow.

An embolus that causes ALI can start in many different locations. It might form in one artery and then travel to another artery. An embolus can also begin in your heart. For example, it can form as a complication of a prior heart attack, as a result of an abnormal heart rhythm (such as AFib), or in association with a prosthetic heart valve.

Other causes of ALI include a tear in an artery wall (dissection) and traumatic injury to a limb.

Risk factors

The most important risk factors for acute limb ischemia are having PAD, having diabetes and/or smoking. Others include:

• AFib
• Aortic diseases, like aneurysm or dissection
• Blood clotting disorders
• Heart valve disease
• High blood pressure
• High cholesterol
• Infective endocarditis
• Recent COVID-19 infection
• Recent heart attack

If you have PAD, following the treatment plan your provider gives you can help slow down the disease progression and lower your risk of ALI. Your provider may prescribe you blood thinners (like Eliquis® or Xarelto®) if you have AFib or a history of blood clots.

Complications of this condition

Acute limb ischemia can lead to limb loss or death. The sooner you get treatment, the better the odds of saving your limb and surviving.

How doctors diagnose this condition

Acute limb ischemia is a medical emergency that needs a fast and accurate diagnosis. This often begins in an emergency room and includes:

• Physical exam: A healthcare provider will carefully check your limb. They’ll feel your skin and check your pulse at many different points. They’ll also look for signs of PAD, like skin ulcers. It helps if you can describe your symptoms and how long they’ve been going on.
• Medical history: Your provider will review your medical history to help find the cause of the blockage. For example, they’ll check if you have a PAD diagnosis or recently had a heart attack. They may also ask about any history of blood clots in your biological family.
• Testing: Your provider may use a handheld ultrasound device to check blood flow in your limb. You might need other imaging tests if you had a stent or graft procedure in the past. This can help your provider see the exact location of the blockage.
• Vascular surgery consultation: A vascular surgeon will evaluate your condition and decide the best plan as quickly as possible.

How is acute limb ischemia treated?

ALI treatment aims to restore blood flow to your limb, save your limb and prevent more blood clots from forming. You may need:

• Anticoagulant therapy: Anticoagulants are medications that thin your blood. Your provider gives you medication (typically heparin) through an IV to keep the clot from growing or breaking away and traveling to another artery. This usually starts right at diagnosis.
• Fibrinolytic therapy: Your provider gives you medications through an IV or catheter to dissolve the clot.
• Thrombectomy: Your provider performs surgery or a minimally invasive procedure to remove the clot.

If your limb is too damaged to save, you may need surgery to remove part of your limb (amputation). This is a last resort that can save your life.

After receiving emergency treatment, you may need further procedures to help blood flow normally in your limb. For example, you may need:

• Endarterectomy to remove plaque from your artery
• Peripheral artery bypass surgery to create a new path for blood to flow

When should I see my healthcare provider?

Your provider will tell you how often you should come in for appointments. These visits are key to managing PAD or other conditions that could lead to ALI. Call your provider if you have any new or changing symptoms.

Call 911 or your local emergency number if you have signs of complications after ALI treatment. The most common ones are:

• Pain, swelling, numbness or weakness in your limb
• Pus or drainage from an incision site
• Bleeding

It’s also possible to experience:

• Chest pain or discomfort
• Confusion or trouble thinking
• Dizziness or balance problems
• Fever
• Shortness of breath

What can I expect if I have this condition?

ALI can affect people in different ways. Acute limb ischemia can lead to limb loss or death. But quick treatment and follow-up care can raise your odds of a better outcome. Talk with your provider about what you can expect.

Is there anything I can do to feel better?

Closely follow your healthcare provider’s guidance on how to care for yourself when you’re back home. They may advise you to:

• Stop smoking or using any tobacco products (this is one of the most important risk factors for PAD and ALI that you can change)
• Add physical activity into your daily routine (your provider will tell you what’s safe in your situation)
• Maintain a weight that’s healthy for you
• Take medications to manage conditions like high blood pressure or high cholesterol

Surviving acute limb ischemia can take a toll on both your body and mind. You may feel weak, exhausted, stressed or scared. It may help to speak with a counselor about how you’re feeling. Your provider can also help connect you with support groups for people with heart or blood vessel conditions.