Embolization (Clot Migration )

An embolus is a clot or perhaps some debris from a buildup of atherosclerotic plaque that has moved from its point of origin, has lodged in a new location, and is blocking the flow of blood. (The embolus is distinguished from a thrombus in that the latter is a clot that forms in the vessel and remains stationary and the former is a clot that travels to another location in the body. Emboli may be small and multiple, or they may be single and massive.

Emboli can also be classified into arterial emboli which originate on the arterial side of the circulation and leave the left side of the heart and can become trapped in any of the arteries of the body. If it is trapped in a brain artery, it can cause stroke  and if trapped in a leg artery the can cause severe pain and gangrene in this leg. The other type is called venous emboli which commonly originate from a thrombus in a big vein in the leg and then migrate to the right side of your heart and from there to your lungs causing pulmonary embolism . Emboli can be life threatening, such as when they lodge in the brain, or can lead to tissue death in an arm or leg if not treated within a few hours. Arterial emboli may originate in the left atrium if you are experiencing atrial fibrillation or in the left ventricle after a heart attack.

Signs and Symptoms of arterial emboli:

• Pain in the affected area;
• Pale, cool skin;
• Numbness.
• Stroke if affecting a brain artery [paralysis or weakness of a limb]

Diagnosis:

When embolization occurs, the flow of blood to the legs and feet may stop abruptly or can slow gradually over weeks and months. If a clot or some debris from an atheromatous plaque in the aorta is carried with the flow of blood through the arteries in the thigh, it may plug the arteries at the level of the knee where the larger artery splits into several small ones.

This obstruction causes sudden pain and pallor in the lower leg and foot. If the clot or debris is not removed by surgery within a matter of hours, the tissue below that level may die and amputation might be necessary. When embolism happens, it is important to protect the leg from any injury by wrapping it loosely with a soft blanket and gauze. Because the foot is very cold, it is tempting to apply heat but this may damage the already compromised tissue. However, protecting the leg from loss of heat by using a blanket, gauze, or other wrap is important.

Your physician will measure the pulse in the affected limb and also may try to localize the embolus by an ultrasound examination or by injecting a dye into the affected blood vessels and taking an x-ray (arteriogram).

Arterial Embolism is an emergency and if the flow of blood is not restored within a few hours, the affected limb could be permanently damaged and amputation may be necessary.

Treatment

Medication:

Your physician may immediately give you a drug to break up the embolus, perhaps delivering it directly to the affected artery through the use of a catheter. This is called thrombolysis. Long-term use of aspirin or a so-called blood thinner (anticoagulant drug) may be appropriate in order to prevent the development of more clots.

Surgery:

If the health of a limb is in danger, immediate surgical removal of the clot may be required. This usually can be performed by using a balloon—tipped catheter inserted into the artery. As it is being withdrawn, the inflated balloon pulls the clot out. Occasionally, replacement or bypass of the blocked vessel is necessary.