Arterial embolism

Definition

Arterial embolism is a sudden interruption of blood flow to an organ or body part due to a clot (embolus).

Alternative Names

Causes, incidence, and risk factors

An embolus is a blood clot or a piece of plaque that acts like a clot. Emboli means more than one clot. If the clot travels from the site where it formed to another location in the body, it is called an embolism.

An arterial embolism may be caused by one or more clots. The clots can get stuck in an artery and block blood flow. The blockage starves tissues of blood and oxygen, which can result in damage or tissue death (necrosis).

Arterial emboli often occur in the legs and feet. Some may occur in the brain, causing a stroke, or in the heart, causing a heart attack. Less common sites include the kidneys, intestines, and eyes.

Atrial fibrillation is a major risk factor for arterial embolism. The risk of an embolism increases when factors that tend to form clots are increased. Such factors include injury or damage to an artery wall and conditions that increase blood clotting (such as increased platelet count).

Another condition that poses a high risk for embolization (especially to the brain) is mitral stenosis. Endocarditis (infection of the inside of the heart) can also cause arterial emboli.

A common source for an embolus is from areas of hardening (atherosclerosis) in the aorta and other large blood vessels. These clots can break loose and flow down to the legs and feet.

Paradoxical embolization can take place when a clot in a vein enters the right side of the heart and passes through a hole into the left side. The clot can then move to an artery and block blood flow to the brain (stroke) or other organs.

If a clot involves the arteries supplying blood flow to the lungs, it is called a pulmonary embolus.

Symptoms

Symptoms may begin quickly or slowly depending on the size of the embolus and how much it blocks the blood flow.

Symptoms of an arterial embolism in the arms or legs may include:

• Cold arm or leg
• Decreased or no pulse in an arm or leg
• Fingers or hands feel cool
• Lack of movement in the arm or leg
• Muscle pain in the affected area
• Muscle spasm in the affected area
• Numbness and tingling in the arm or leg
• Pale color of the arm or leg (pallor)
• Weakness of an arm or leg

Later symptoms:

• Blisters of the skin fed by the affected artery
• Shedding (sloughing) of skin
• Skin erosion (ulcer)
• Tissue death (necrosis; skin is dark and damaged)

Symptoms of a clot in an organ vary with the organ involved but may include:

• Pain in the part of the body that is involved
• Temporarily decreased organ function

Signs and tests

The health care provider may find decreased or no pulse, and decreased or no blood pressure in the arm or leg. There may be signs of tissue death or gangrene.

Tests to diagnose arterial embolism or reveal the source of emboli may include:

• Angiography of the affected extremity or organ
• Doppler ultrasound exam of an extremity
• Duplex Doppler ultrasound exam of extremity
• Echocardiogram
• MRI
• Myocardial contrast echocardiography (MCE)
• Plethysmography
• Transcranial Doppler exam of arteries to the brain
• Transesophageal echocardiography (TEE)

This disease may also affect the results of the following tests:

• Euglobulin lysis time (ELT)
• Factor VIII assay
• Isotope study of the affected organ
• Plasminogen activator inhibitor-1 (PAI-1) activity
• Platelet aggregation test
• Tissue-type plasminogen activator (t-PA) levels

Treatment

Arterial embolism requires prompt treatment at a hospital. The goals of treatment are to control symptoms and to improve the interrupted blood flow to the affected area of the body. The cause of the clot, if found, should be treated to prevent further problems.

Medications include:

• Anticoagulants (such as warfarin or heparin) can prevent new clots from forming
• Antiplatelet medications (such as aspirin, ticlopidine, and clopidogrel) can prevent new clots from forming
• Painkillers given through a vein (by IV)
• Thrombolytics (such as streptokinase) can dissolve clots

Some people need surgery. Procedures include:

• Bypass of the artery (arterial bypass) to create a second source of blood supply
• Clot aspiration (thromboaspiration)
• Clot removal through a balloon catheter placed into the affected artery or through open surgery on the artery (embolectomy)
• Opening of the artery with a balloon catheter (angioplasty) with or without a stent implanted

Support Groups

Expectations (prognosis)

How well a patient does depends on the location of the clot and how much the clot has blocked blood flow. Arterial embolism can be serious if not treated promptly.

The affected area can be permanently damaged. Up to approximately 25% of cases require amputation.

Arterial emboli can come back (recur) even after successful treatment.

Complications

• Acute MI
• Infection in the affected tissue
• Septic shock
• Stroke (CVA)
• Temporary or permanent decrease or loss of other organ functions
• Temporary or permanent kidney failure
• Tissue death (necrosis) and gangrene
• Transient ischemic attack (TIA)

Calling your health care provider

Go to the emergency room or call the local emergency number (such as 911) if you have symptoms of arterial embolism.

Prevention

Prevention begins with identifying the source of the blood clot. If your health care provider determines you have a high risk for blood clots, you may be prescribed blood thinners (such as warfarin or Coumadin) to prevent them from forming. Antiplatelet drugs may also be needed.

The risk for both atherosclerosis and clot formation increases in persons who:

• Are inactive and do little exercise
• Are overweight
• Are under stress
• Smoke

Taking steps to reduce hardening of the arteries (atherosclerosis) may reduce your risk of an arterial embolus forming from a piece of plaque.

visHeader

References

Clagett GP, Sobel M, Jackson MR, Lip GY, Tangelder M, Verhaeghe R. Antithrombotic therapy in peripheral arterial occlusive disease: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest. 2004;126(3):609S-626S.

Hirsch AT, Haskal ZJ, Hertzer NR, Bakal CW, Creager MA, Halperin JL, et al. ACC/AHA 2005 practice guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic). Circulation. 2006;113:e463-e654.

Goldman L. Approach to the patient with possible cardiovascular disease. In: Goldman L, Ausiello D. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 48.