Carotid artery disease is important in the pathogenesis of stroke. Almost one half of all cases of stroke have their origins in disease of the carotid arteries. These arteries are a common site of narrowing particularly if patients are subject to some of the cardiaovascular risk factors of smoking, high cholesterol, diabetes and blood pressure. The arteries tend to narrow and form an irregular lining. As the blood crosses the artery wall the narrowness produces an increase in the speed of the blood flow which in combination with the irregular lining may result in small particles becoming dislodged. These particles pass into the blood stream to the brain and lodge in the smaller arteries supplying the brain. This results in small portions of the brain becoming starved of blood and can produce a stroke or mini stroke. The most important elements of dealing with this is improving the patients risk profile by stopping smoking, reducing blood pressure, controlling diabetes, cholesterol levels and other cardiovascular risk factors. The next step is to start an anti platelet or blood thinning agent such as Aspirin. Altering all of these risk factors is designed to improve the risk of having a stroke or mini strokes in the future. Once the risk factors have been adjusted and the right medication has been started then some consideration should be given to carotid artery surgery. Surgery on the carotid artery is designed to remove the inner, irregular layer by separating it from the rest of the artery. Once it has been removed the artery is closed and hopefully the blood flow will be less turbulent. This procedure is called carotid endarterectomy.
Patients with carotid artery disease can be divided generally into two groups: 1) those patients who have already had a mini stroke and 2) those patients who have not had symptoms of any kind have had carotid disease picked up on a scan either as a result of screening or for some other reason.
Carotid disease is diagnosed by ultrasound and categorised as mild moderate and severe. In patients who have had a stroke or mini stroke before and who have severe disease carotid endarterectomy is recommended. In patients who have never had a stroke or mini stroke the benefits are more marginal however surgery should be considered in male patients with severe disease under the age of 75 and female patients with severe disease under the age of 70. Surgery is not considered for everybody as it has a small risk of producing a stroke itself. That risk is about 3% for all surgery. The result is that the risk of surgery has to be balanced against the risk of leaving the patient being treated only with risk factor modification and medication.
Carotid stenting is another alternative treatment however some studies have suggested that the stroke rate from treatment may not be quite as good as surgery. At present in Ireland this treatment tends to be reserved for patients for whom surgery specifically is not a good option. Of course as these treatments improve they well become more and more commonly performed and perhaps even accepted as the treatment of choice