Acute Limb Ischemia
Acute Limb Ischemia (ALI) is a medical emergency marked by a sudden interruption of blood flow through a limb’s blood vessels. Associated with a high-risk of limb loss and death, early diagnosis and intervention are crucial to improving patient outcomes and preserving limb function. ALI is often a complication of peripheral artery disease (PAD), a chronic condition suffered by more than 8 million Americans ages 40 and older.
More About This Condition
ALI occurs when there is a sudden interruption of blood flow through blood vessels of the arm or leg. In most cases, flow is blocked by thrombus, a thickened mass of blood or clot. Such a blockage prevents necessary oxygen and nutrients from reaching cells that depend on them for survival. How long tissue remains viable or “alive” depends on the degree to which a vessel is blocked, as well as the presence of alternate vessels through which blood can flow to reach at-risk tissue.
ALI can occur due to the following events:
- Acute thrombosis occurs when a blood clot (thrombus) forms at the site of plaque buildup (atherosclerosis) in an artery.
- Arterial embolism occurs when a blood clot (embolus) breaks off from elsewhere in the body, such as the heart, travels through the bloodstream, and becomes lodged in an artery.
IMPORTANT NOTE: This overview is provided for informational purposes only and should not be used as a substitute for talking with your doctor. Be sure to talk with your doctor for a complete discussion of this condition as well as the benefits and risks of any treatment options.
Symptoms
Symptoms may include:
- Pain
- Pulselessness
- Numbness (occurs in about half of patients)
- Pale color
- Paralysis
- Inability to regulate temperature (cold sensation)
Diagnosis
Your doctor may:
- Ask you or a family member about your medical history, such as claudication (limping due to leg pain), diabetes, smoking, heart disease, palpitations, atrial fibrillation, and previous ischemic symptoms.
- Ask about your signs and symptoms and when they began.
- Conduct a physical examination focusing on sensory and motor function, which is critical for determining the level of ischemia and the urgency of intervention.
Your doctor may order one of more of the following tests:
- Ultrasound imaging uses sound waves to produce pictures of the structures inside the body.
- Computed tomography (CT) scan is an imaging test that uses a combination of X-rays and computer technology to produce images of the body. CT with contrast, a dye-like substance, enhances the image of the organ or tissue under study.
- Magnetic resonance angiography (MRA) uses a powerful magnetic field, radio waves and a computer to evaluate blood vessels and help identify abnormalities or diagnose atherosclerotic (plaque) disease.
Treatment
Treatment for this condition must always be discussed with your doctor for a full discussion of options, risks, benefits, and other information.
Treatment of a threatened limb is time critical, as irreversible damage can occur within 4 to 6 hours from the time an artery becomes blocked by clot. Immediate endovascular or surgical removal of the clot is recommended to restore blood flow to the limb and prevent amputation.
Endovascular treatment consists of either an injection of a clot-busting drug or mechanical thrombectomy, a minimally invasive procedure that physically removes clot from blocked arteries. The two can be used in combination.
Now, physicians can use computer-aided thrombectomy, which is designed to address blood loss concerns for efficient clot removal across multiple disease states including ALI.