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

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.