Arterial Embolism

Arterial embolism is a sudden blockage of an artery by material carried in the bloodstream from elsewhere, called an embolus. An embolus is usually a blood clot, but it can also be a fragment of plaque, a clump of bacteria from an infected heart valve, or part of a heart tumor. The embolus travels with the blood until it lodges in a smaller artery, instantly stopping blood flow to the tissue beyond it.

Where the Clot Comes From

In most cases, the embolus comes from the heart. A common cause is atrial fibrillation, a rhythm disorder that lets blood pool in the left atrium so it clots easily, covered on the Atrial Fibrillation page. Clots can also form in the left ventricle after a heart attack, on an artificial heart valve, or with a valve infection, covered on the Infective Endocarditis page. Other sources are a widened section of the aorta or of the artery behind the knee, and plaque in the aorta. In people with a small opening in the wall between the heart chambers, a clot from a vein can cross to the left side, covered on the Patent Foramen Ovale page.

Where the Blockage Occurs

An embolus often lodges in the leg arteries, especially at the groin and behind the knee, as well as in the arm arteries. A suddenly blocked leg becomes painful, pale, cold, and numb. This is called acute limb ischemia. An embolus can also block an artery in the brain and cause a stroke, covered on the Ischemic Stroke page, an artery in the eye, covered on the Eye Stroke page, and arteries to the intestines or kidneys. This page focuses on blockages in the legs, arms, and abdominal organs.

Different from Pulmonary Embolism and Chronic Narrowing

Pulmonary embolism happens on the venous side: a clot from a leg vein travels to the lung arteries, covered on the Pulmonary Embolism page. Arterial embolism happens in the arteries that carry blood from the heart to the body. A sudden blockage can also occur when a clot forms directly in a leg artery that has long been narrowed by plaque. The symptoms are similar and treatment is just as urgent. Narrowing that worsens slowly over weeks is covered on the Critical Limb Ischemia page.

Why Every Hour Counts

Leg muscles and nerves can survive only a few hours without blood flow. The sooner blood flow is restored, the greater the chance of saving the leg and keeping it working as before. The ESVS 2020 guidelines recommend giving a blood thinner as soon as the diagnosis is made, followed by opening the artery as quickly as possible if the leg is threatened, for example by removing the clot with a balloon catheter. After that, the doctor looks for the source of the clot so the blockage does not happen again.

Arterial embolism is diagnosed mainly from the symptoms and a physical examination in the emergency room. The doctor compares the color, temperature, pulse, sensation, and strength of movement of the affected leg or arm with the healthy side, often using a handheld Doppler device to listen to blood flow. From this, the doctor judges how threatened the limb is. If sensation or movement is already affected, treatment is not delayed for time-consuming tests.

When time allows, CT angiography or duplex ultrasound maps the location of the blockage. Catheter angiography can be done at the same time as the procedure to open the artery. Blood tests assess kidney function, muscle damage, and blood clotting. Once blood flow is restored, an ECG, heart rhythm recording, and echocardiography are used to look for the source of the clot, such as atrial fibrillation or a clot inside the heart.

Arterial embolism is an emergency. If your leg or arm suddenly becomes painful, pale, cold, numb, or weak, call an ambulance (119) right away or ask someone to take you to the nearest emergency room. Do not apply hot compresses, massage the limb, or wait for the symptoms to ease, because every hour affects the chance of saving the limb. Toes that suddenly turn blue and painful also need to be checked right away.

Make an appointment with a doctor if:

• Your heartbeat often feels irregular
• You have atrial fibrillation and are unsure about your anticoagulant medicine
• You have had an arterial embolism and need follow-up on the source of the clot
• You have an aneurysm of the aorta or a leg artery that has not been treated