Carotid artery stenosis

As carotid stenosis refers to a narrowing of the cerebral arteries carotid artery (CCA ) or internal carotid artery ( ICA). The most common cause for carotid artery stenosis is atherosclerosis. During carotid stenosis without symptoms are almost always treated with medication, even if the vessel is heavily concentrated carotid stenosis with symptoms of circulatory disorder of the brain or eye are often treated surgically.

Dissemination

The prevalence of carotid artery stenosis in the general adult population, that is, in people without symptoms, is between 0 and about 11%. Carotid stenosis are more common with age and are more common in women than in men. Also increase other risk factors for the development of atherosclerosis, the likelihood of carotid artery stenosis: While elevated blood lipid levels increase the likelihood of carotid stenosis only slightly, carotid stenosis patients come in smokers with hypertension or diabetes mellitus two to three times more common.

In approximately 20% of patients with stroke stenosis or occlusion of the ( extracranial ) is diagnosed carotid arteries.

Cause

The most common cause of carotid artery stenosis is atherosclerosis in more than 90 % of all cases. Risk factors are high blood pressure, smoking, older age or increases in blood lipid levels.

Furthermore, even vasculitis, ie inflammatory diseases of the blood vessels, fibromuscular dysplasia and dissection can lead to carotid artery stenosis.

Clinical manifestations

Carotid stenosis usually cause no symptoms for a long time. They eventually manifest themselves in transitory ischemic attacks, in which a reversible neurological deficit occurs. This should be seen as harbingers of an irreversible stroke. As a possible symptom also comes amaurosis fugax in question, retinal temporary blindness due to an occlusion of the central artery.

Nine-tenths of all ischemic strokes affecting the supply area of ​​the carotid artery. One-fifth of strokes caused by constrictions of the carotid artery outside the skull. Around 30,000 people suffer a stroke each year in Germany this cause. However, not every stenosis lead to a stroke. In an asymptomatic stenosis of less than 80 % of the lumen, the annual risk of stroke is around 1-2%. The risk increases with both the degree of stenosis as well as with the appearance of characteristic symptoms such as a Transient ischemic attack (TIA). Stenoses with a luminal laying of over 80 % have a risk of 3-5%. After a TIA, and the presence of a stenosis over 70 % suffer 40% of patients within two years of a stroke. With the simultaneous closure of the artery on the opposite side, the risk is 70%.

Diagnosis

Simplest step to diagnosis is the auscultation of arteries using the stethoscope. Stenosis at the carotid bifurcation can thus be seen with high security. Also half of the stenosis of the internal carotid artery show still audible Stenosegeräusch.

Next step in diagnosis is the study of blood flow in the cerebral arteries using a color-coded duplex ultrasound examination. The aim of this study is to determine the degree of stenosis, the angiographic criterion of reduction in diameter of the lumen is used as the gold standard. Since in the case of a narrowing of the vessel is the same volume flow of blood must flow through the restriction as shown by the normal large vessel before and after the constriction ( → continuity equation ), the rate of blood is increased in the constriction. Therefore, the degree of stenosis is essentially determined by the measured with the pulsed Doppler peak systolic velocity. In addition, the ratio of peak velocity in the internal carotid artery and the common carotid artery is still used to eliminate the influence of hypertension and the elasticity of the vessels. Moreover, can be characterized by morphology of plaques ultrasound, that is, the deposits on the Karotiswänden are examined for their surface condition and constitution thereof.

In addition, stand angiography procedure using computed tomography or magnetic resonance imaging are available. For clarifying by constrictions of the blood vessels within the cranium, both methods can also be employed.

Therapy

First up is the therapy of cardiovascular risk factors. Each of the following items represents a prognostically important therapeutic option, which prevent Stenosewachstum, with stringent setting can even be reversed. These include nicotine abstinence, exercise, diet, cessation of blood lipids, and blood pressure- lowering therapy, which must be carefully titrated at higher grade stenoses.

Standard treatment method for symptomatic patients, the carotid thromboendarterectomy ( carotid TEA). In this method, the atherosclerotic vascular stenosis is enucleated with the inner wall layers of the vessel., The vessel is sutured with a plastic patch and thereby expanded. The risk of stroke or death from complications during surgery was in an international literature review from 1994-2000 of 2.8% in asymptomatic stenosis and 5.1% for symptomatic stenosis. Comparable data for quality assurance within Germany from 2002 showed 1.8% respectively 3.0%.

To follow-up after carotid TEA administration of Thrombozytenagreggationshemmern (eg, acetylsalicylic acid 100 mg / day ) is necessary. To observe any possible re-closures, indicated six months after the operation, a scan.

The Karotisstentangioplastie (or PTA - percutaneous transluminal angioplasty ) is used to treat: this extends the stenosis with a balloon catheter and kept open with the help of a stent.