Carotid Artery Disease, Strokes and TIAs
A stroke (or "brain attack") results from damage to the brain usually due to a blockage in a blood vessel supplying the brain or bleeding on the brain. It can affect people in many different ways, the most common being paralysis or weakness down one side of the body or difficulty speaking or seeing. A TIA (transient ischaemic attack or "mini stroke") is when the above mentioned symptoms occurs for a short period and then disappear completely. The significance of a TIA is that it is a warning sign that a major stroke may be about to occur. Stroke is the third most common cause of death in the western world after cancer and heart disease. In a recent poll it was the medical condition New Zealanders over the age of 65 feared the most. As well as death it can dramatically alter quality of life, often leaving patients totally dependent on others to help them perform everyday normal activities.
One of the most common causes of stroke and TIA is a narrowing in the carotid artery. There are two carotid arteries, one on each side of the neck. These are the main blood vessels supplying blood to the brain. There are also two smaller arteries on each side of the neck, the vertebral arteries, that also help supply blood to the brain. Half way up the neck the carotid artery divides into two branches - the external carotid artery, which supplies the face, and the internal carotid artery which supplies the brain. This branch point is a common location to develop atherosclerotic plaque. Tiny fragments of this plaque can break off and travel up to the brain blocking arteries and thus causing a TIA or stroke. If the plaque gets very severe it can totally block the carotid artery which can also cause a stroke. Contrary to what one might expect the right side of the brain (which is supplied by the right carotid artery) controls the left hand side of the body and vice versa. Therefore if you have had a TIA affecting the left side of your body it may be due to a problem with your right carotid artery!
Most people who have had a stroke or TIA should have their carotid arteries checked to make sure they are not narrowed. The most common way to check this is by doing an ultrasound scan. A CT scan or MRI scan can also be done to look for narrowing or to provide additional information to help your doctor plan your treatment. If the carotid artery is severely narrowed (a "carotid stenosis") your doctor may recommend an operation (carotid endarterectomy) to prevent you having another stroke or TIA. If your have had a stroke, TIA or have a narrowing in your carotid artery it is very important your doctor prescribes you appropriate medication. This would normally include a blood thinning agent (e.g. aspirin), a cholesterol lowering agent (e.g. simvastatin) and a medication to lower your blood pressure if it is elevated.