Carotid Artery Disease: Causes and Treatment

The blood vessels that deliver blood to the brain via the neck are called the carotid arteries. You can feel their pulsations in your neck. Narrowing of these vessels, due to deposition of fat and cholesterol in its wall, causes a reduction in the flow of blood to the brain resulting in a disease called carotid artery disease. Sometimes there can be permanent damage to the brain because of reduced blood flow, this condition is commonly called stroke. Every year about 750,000 individuals in the US become victims of stroke.

Causes of Carotid Artery Disease

Carotid artery disease is caused due to the narrowing of the blood vessel supplying the brain. There are multiple risk factors which affect the development of this disease like:

• Diabetes
• High blood pressure
• High level of fat in the blood increases the chances of their deposition in the wall of carotid artery
• Smoking
• Gender: males are more likely to be affected
• Elderly
• When there is an injury to the affected segment of the artery a clot is formed over it. The disease is detected when small fragments of cholesterol and blood clots break off, from the deposition in the wall, and get lodged in a smaller artery in the brain leading to a sudden loss of blood supply to a particular area in the brain.

Symptoms of Carotid Artery Disease

Most of the individuals with carotid artery disease are asymptomatic until they experience a Transient ischemic attack (TIA) or a stroke which are caused due sudden loss of blood supply to a part of the brain. The severity of the symptoms depends on the size of the blood vessel and the area of the brain involved.

• Transient ischemic attack: also known as a mini-stroke, you might experience symptoms that are sudden in onset which resolve in less than an hour. The symptoms can be anything ranging from Blurring of vision in either or both eyes
• Slurring of speech
• Difficulty in walking
• Weakness on one side of the face
• Deviation of the mouth towards one side
• Difficulty in remembering words to say
• On experiencing any of these symptoms you should visit your physician as soon as possible because a TIA is an indication of a carotid artery disease. Individuals who have experienced a TIA have are at an increased of developing a stroke
• Stroke: symptoms are similar to TIA but they do not resolve as quickly as in TIA.

Diagnostic Tests

To identify the cause of your symptoms your doctor will first do a physical examination to look for signs of a stroke or TIA. To confirm your doctor might order a panel of tests like:

• Ultrasonography: This scan uses sound waves to visualize the blood vessel and asses the flow of blood in it. This will help in identifying the extent and location of narrowing in your carotid artery
• MRI scan or a CT scan: to look for signs of damage to the brain due to sudden loss of blood supply
• MR angiography or CT angiography : for better visualization of the blood vessels in the brain and the neck to look for the vessel with the narrowing or blockage
• Your doctor might order a series of blood tests to look for risk factors like blood sugar to look for diabetes and serum lipid profiles.

Treatment of Carotid Artery Disease

• The treatment of carotid artery disease depends upon the extent of narrowing of the artery and on whether the patient is symptomatic or not. It aims to reduce recurrence of TIA or stroke and also halt the progression of the disease by reducing the modifiable risk factors.
• Controlling blood pressure: hypertension is the most significant risk factor. The first number in your blood pressure measurement should be less than 140 or if you are diabetic, less than 130. Your doctor will prescribe anti-hypertensive medications to control your blood pressure. Dietary changes and regular exercising also help in controlling blood pressure
• Treatment of high cholesterol: your doctor might prescribe statins, cholesterol lowering drugs, to control the levels of cholesterol in the blood. Studies have shown that statins help in reducing the risk of stroke in individuals with normal blood cholesterol also. Changing your diet, losing weight and exercising regularly also help in reducing blood cholesterol levels.
• Treatment of diabetes: if you have diabetes the chances that you develop a stroke is about 4 times higher than the normal population, hence your doctor will prescribe medications to keep your blood sugar in a particular range.
• Blood thinning agents: drugs like aspirin and clopidogrel reduce the risk of formation of clot over the fat deposits in the wall of the artery, hence reducing the risk of stroke.
• Carotid endarterectomy: it is a surgery performed under general anaesthesia. The surgeon opens the carotid artery and removes the cholesterol deposit leading to a normalisation of blood flow.
• Carotid artery stenting: under x ray guidance a small tube (catheter) with a deflated balloon and a stent, is introduced into your body through the artery in the groin. After reaching the carotid artery the balloon is inflated at the site of the narrowing. The artery and the stent expand with the balloon and the stent pushes away the cholesterol deposit in the artery and restores the blood flow.

Complications of Carotid Artery Disease

The most dreaded complication of carotid artery disease is a stroke which can leave the patient in a debilitated condition.  Although most individuals with this disease are asymptomatic, individuals with a narrowing of more than 70% will be suggested a corrective surgery to reduced their high risk of stroke.

Prognosis of Carotid Artery Disease

If you have asymptomatic carotid artery disease, the risk of developing a stroke annually is nearly 2%. This risk rises to 13% if you have symptomatic carotid artery disease i.e. you have had a TIA or stroke before. Carotid endarterectomy has greater beneficial effect when performed within 2 weeks of onset of symptoms. The benefits are more pronounced in older individuals and in males.

Resources:

• American college of cardiology
• American heart association
• Society for Vascular Surgery