Carotid Occlusive Disease

Carotid occlusive disease, also called carotid stenosis, occurs when one of the carotid arteries in the neck, which supply blood to the brain, becomes narrowed or blocked. The narrowing usually is the result of the buildup of plaque, which is made up of fatty material and blood platelets, along the vessel walls. The buildup may either completely block the artery or it may lead to the obstruction of an artery further in the brain, leading to a stroke or a transient ischemic attack (TIA or "mini-stroke"). The plaque buildup can cause an obstruction (called an embolus) in other cerebral arteries if a piece of the fatty deposit breaks off and flows up to block a more narrow artery, or if the deposit causes a thrombus, or clot, to form.

The risk factors for carotid occlusive disease include high blood pressure, heart disease, diabetes, smoking, obesity, family history, elevated homocysteine levels, and TIAs.

Symptoms

A TIA, or "mini-stroke," is a temporary condition is which the blood flow to a part of the brain is restricted, leading to transient neurological deficits. A stroke is when the blood supply to a part of the brain is completely blocked, leading to the death of brain cells and often death. Stroke is the third leading cause of death in United States-more than 150,000 deaths each year-and approximately 50 percent of all strokes are caused by buildup of plaque in the arteries.

A carotid occlusion does not always lead to a stroke. Sometimes other arteries will expand to transport the blood the brain needs if the carotid arteries are blocked. Also, the carotid arteries are big enough that a significant blockage still will allow enough blood to flow through. A serious blockage however, increases the risk that an embolus will form.

Diagnosis

Often carotid occlusive disease is not diagnosed until a patient has a stroke, but imaging techniques have made it possible to catch an occlusion before that happens. Carotid stenosis is assessed first with a thorough physical examination. This examination can reveal specific neurological, motor, and sensory deficits that can provide clues about both the extent and location of an occlusion. In addition, physicians may be able to hear changes in blood flow in the carotid arteries with a stethoscope. A complete diagnostic workup also includes carotid Duplex ultrasound followed by magnetic resonance imaging (MRI) and computed tomography (CT) scans, which are noninvasive techniques. Complex cases may require an informal angiogram in which a catheter (rubber tube) is inserted into the vessels to project a dye that provides pictures of the blood vessels.

Treatment

Treatment, which is determined by the extent of the narrowing and the condition of the patient, may include medication to treat the underlying risk factors associated with carotid occlusive disease, including antihypertensives for high blood pressure, medication to reduce cholesterol levels, and diabetes medication.

In cases of serious obstruction, surgical procedures may be employed to prevent strokes from occurring. Carotid endarterctomy and endovascular strategies most often are used. Carotid endarterctomy is the surgical removal of the occluding mass from the lining of the artery to allow blood to flow into the brain normally. Angioplasty and stenting, which are used in patients who cannot undergo surgery, are endovascular procedures used to open flow through the artery with the use of a catheter, or tube. The catheter usually is inserted in an artery in the groin and guided up to the site of the occlusion. Once there, it can deploy a balloon that pushes open the narrow artery and displaces the plaque. Then a stent, a self-expanding metallic mesh tube, can be implanted to hold the artery open and maintain blood flow.

Carotid occlusive disease is a complex condition, and should be addressed at major centers with experts experienced in its treatment.