Definition and Overview

Carotid artery occlusion (CAO) is a medical condition in which the arteries that supply blood to the brain are blocked. Thus, the brain does not get its supply of oxygen and nutrients. This can cause brain cells to die in just a matter of minutes. When this happens, the patient will have a stroke. This often leads to permanent brain damage or even death.

There are two carotid arteries. They are located on each side of the neck. When they are blocked, it is usually because of plaque build-up. Plaque is made up of substances found in the blood. These include calcium and cholesterol. As blood circulates in the body, a small amount of these substances can be stuck within a blood vessel. Over time, they can build up and cause a blockage. Many patients show signs of stroke when their arteries begin to narrow. But the symptoms go away when blood flow to their brain is restored. Unless they seek treatment, their arteries can eventually become totally blocked. This is often fatal.

Causes of Condition

The condition is often due to plaque build-up. It can also be caused by damage to the arteries.

A number of factors can increase the risk of the condition. These include disorders and diseases that weaken and damage the blood vessels. Some of the most common are diabetes and high blood pressure. Other risk factors are obesity and a sedentary lifestyle. Patients with these factors can lessen their risk of stroke. They can do so by seeking treatment for their underlying conditions. In many cases, these can be kept under control with medications and by making healthy lifestyle changes.

Undergoing annual check-up can also help lower their risk. Early signs of CAO can be detected during a physical exam. When caught early, preventive measures can be taken to prevent a stroke from occurring.

Key Symptoms

Blocked carotid arteries are the main cause of stroke. Symptoms of stroke include:

  • Sudden weakness or numbness of one side of the body

  • Sudden confusion

  • Sudden difficulty talking or understanding speech

  • Sudden vision and balance problems

Patients often do not have early warning signs before a stroke. But some report having severe headaches and sudden vision changes beforehand.

Who to See and Types of Treatments Available

A blocked carotid artery is diagnosed with a number of tests and procedures. Doctors often start with carotid ultrasound. This test uses sound waves to measure the pressure in the arteries. If the blood flow is slower than normal, doctors will order imaging tests. These include an MRI and a CT scan. A cerebral angiography is also often used. These tests provide clear images of the artery. Thus, they can confirm if there is a blockage. They can also identify the exact location of the blockage.

Treatment depends on the severity of the blockage. It also depends on whether just one or both the carotid arteries are blocked. Minor to moderate cases can be treated with medications. Patients are given certain drugs for diseases that increase their risk of CAO. These include diabetes and high blood pressure. Patients are also advised to make healthy lifestyle changes. It is important that they eat a well-balanced diet and exercise often. They must also work closely with their doctors to monitor their condition.

Patients may need surgery to remove the plaque that blocks the artery. This is often a traditional open surgery. This requires an incision in the neck area to access the affected artery. The blocked artery can also be widened to restore normal blood flow. This can be done using a less invasive method. For this procedure, a tube with a balloon on its tip is inserted into the carotid artery. Once in position, the balloon is inflated. This action pushes plaque to the walls of the artery. This gives the blood more room to flow in. A stent can be left in place to keep the artery open.

Treatment is different for patients who already had a stroke. Doctors will focus on restoring normal blood flow to their brain. They will do so by injecting tissue plasminogen activator into the patient’s vein. This medication works by dissolving the blockage in the affected artery. It is important to note that this treatment only works if it is given within three hours of having a stroke. Once the blood flow to the brain is restored, patients will need the same procedures mentioned above.


  • North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. 1991 Aug 15. 325(7):445-53.

  • Brown K, Itum DS, Preiss J, Duwayri Y, Veeraswamy RK, Salam A, et al. Carotid artery stenting has increased risk of external carotid artery occlusion compared with carotid endarterectomy. J Vasc Surg. 2015 Jan. 61 (1):119-24.

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