Carotid stenosis

Macroscopic view of a stenosing plaque of the carotid fork

As carotid stenosis refers to a narrowing of the vessels supplying the brain common carotid artery (ACC) or the internal carotid artery (ICA). The most common cause of carotid stenosis is arteriosclerosis . While carotid stenoses with no symptoms are almost always treated with medication, even if the vessel is severely narrowed, carotid stenoses with symptoms of circulatory disorders of the brain or eye are often treated surgically.

distribution

Prevalence of asymptomatic carotid stenosis in different age groups

The prevalence of carotid stenosis in the general adult population, that is, in people without symptoms, is between 0% (women under 50 years) and around 7.5% (men over 80 years). Carotid stenosis is more common with age and is more common in men than women. Other risk factors for developing atherosclerosis also increase the likelihood of carotid stenosis: While elevated blood lipids only slightly increase the likelihood of carotid stenosis, carotid stenoses are two to three times more common in smokers, patients with high blood pressure or diabetes mellitus .

A stenosis or obstruction of one of the (extracranial) carotids is diagnosed in around 20% of patients with a stroke.

root cause

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

Furthermore, vasculitis , i.e. inflammatory diseases of the blood vessels , fibromuscular dysplasia and dissection can also lead to carotid stenosis.

Clinical manifestations

Carotid stenosis usually does not cause symptoms for a long time. Finally, they manifest themselves in transient ischemic attacks , in which a reversible neurological deficit occurs. These are to be seen as harbingers of an irreversible stroke. Another possible symptom is amaurosis fugax , a temporary blindness due to an occlusion of the central retinal artery .

Nine tenths of all ischemic strokes affect the carotid artery supply area. One fifth of strokes are caused by narrowing of the carotid artery outside the skullcap. Around 30,000 people in Germany suffer a stroke of this cause every year. However, not every stenosis leads to a stroke. With an asymptomatic stenosis below 80% of the lumen , the annual risk of an insult is around 1–2%. The risk increases with the degree of stenosis and with the occurrence of characteristic symptoms such as a transitory ischemic attack (TIA). Stenoses with a lumen displacement of over 80% have a risk of 3–5%. After a TIA and a stenosis of over 70% is present, 40% of patients will suffer a stroke within two years. If the artery on the opposite side is blocked at the same time, the risk is 70%.

diagnosis

Severe stenosis of the internal carotid artery on ultrasound

The easiest step towards diagnosis is auscultation of the arteries with the help of a stethoscope . Stenoses on the carotid fork can thus be detected with a high degree of certainty. Half of the stenoses of the internal carotid artery still show an audible stenosis noise.

Degree of stenosis in percent (NASCET)	Top speed in ACI (cm / s)	Top speed ratio ACI / ACC
<50	<125	<2
50-69	> 125	2-4
70-89	> 230	> 4
> 90	> 400	> 5

The next step in diagnosis is to examine the blood flow in the arteries supplying the brain using a color-coded duplex ultrasound scan . The aim of the investigation is to determine the degree of stenosis, using the angiographic criterion of reducing the diameter of the lumen as the gold standard . Since the same volume flow of blood has to flow through the constriction in the event of a constriction of the vessel as it does through the normal-sized vessel before and after the constriction (→ continuity equation ), the speed of the blood in the constriction is increased. That is why the degree of stenosis is essentially determined by the systolic peak velocity measured with the PW Doppler . In addition, the quotient of the peak velocity in the internal carotid artery and the common carotid artery is used to eliminate the influence of high blood pressure and the vasodilability . In addition, the morphology of plaques can be characterized with ultrasound, i.e. the deposits on the carotid walls are examined for their surface properties and composition.

Stenosis grading according to NASCET = (AB) / A and ECST = (CB) / C

In addition, angiography methods using computed tomography or magnetic resonance tomography are available. Both methods can also be used to clarify constrictions in the blood vessels within the skull.

therapy

PTA
A before
B during and
C after dilation

First and foremost is the therapy of cardiovascular risk factors. Each of the following points represents a prognostically significant therapeutic option that can prevent the growth of stenosis, or even reverse it if the setting is strict. These include abstinence from nicotine, exercise, diet, adjustment of blood lipids and antihypertensive therapy, which must be carefully titrated in the case of severe stenoses.

The standard treatment method for symptomatic patients is carotid thrombendarterectomy (carotid TEA). In this procedure, the arteriosclerotic vascular narrowing is peeled off with the inner wall layers of the vessel. The vessel is sewn with a plastic patch and thereby expanded. In an international review of the literature from 1994–2000, the risk of a stroke or fatal complications during surgery was 2.8% for asymptomatic stenoses and 5.1% for symptomatic stenoses. Comparable data from quality assurance within Germany from 2002 showed 1.8% and 3.0% respectively.

For follow-up care after carotid TEA, the administration of platelet aggregation inhibitors (e.g. acetylsalicylic acid 100 mg / day) is necessary. An ultrasound examination is indicated six months after the operation in order to observe any reclosures.

Also, the Karotisstentangioplastie (or PTA - percutaneous transluminal angioplasty) is used for the treatment: this is a balloon catheter expands the stenosis and with the aid of a stent held open.

literature

• S3 guideline for extracranial carotid stenosis; Diagnostics, therapy and aftercare of the German Society for Vascular Surgery and Vascular Medicine and the Society for Operative, Endovascular and Preventive Vascular Medicine. In: AWMF online (as of 2012)
• H.-H. Eckstein, P. Heider, O. Wolf, M. Hanke: Vascular surgery. In: JR Siewert Surgery. 8th edition. Heidelberg 2006, ISBN 3-540-30450-9 , pp. 440-448.
• CM Rumack et al: Diagnostic Ultrasound. 2011, ISBN 978-0-323-05397-6 .
• JR Siewert, RB Brauer: Basic Knowledge Surgery 2010, ISBN 978-3-642-12379-5 .
• A. Thrush, T. Hartshorne: Vascular Ultrasound. How, Why and When. 2011, ISBN 978-0-443-06918-5 .

Individual evidence

1. ↑ ^{a b c} M. de Weerd et al .: Prevalence of asymptomatic carotid artery stenosis in the general population: an individual participant data meta-analysis. In: Stroke. 2010 Jun; 41 (6), pp. 1294-1297, PMID 20431077 , doi : 10.1161 / STROKEAHA.110.581058 .
2. ↑ ^{a b c d} J. R. Siewert (2006), p. 441.
3. ↑ JR Siewert (2010), p. 199.
4. ↑ CM Rumack, pp 979-981.
5. ^ Information from the Bremen Vascular Center
6. ↑ JR Siewert (2006), p. 442.
7. ↑ MT Magyar, EM Nam, L. Csiba, MA Ritter, EB Ringelstein, DW Droste: Carotid artery auscultation - anachronism or useful screening procedure? In: Neurol Res. 2002 Oct; 24 (7), pp. 705-708, PMID 12392209 .
8. ↑ Joint recommendations for reporting carotid ultrasound investigations in the UK , quoted from A. Thrush, p. 106.
9. ↑ ^{a b} A. Thrush, p. 103.
10. ^ A. Thrush, p. 52.
11. ↑ CM Rumack, S. 952nd
12. ↑ Journal for Hypertension (PDF; 2.0 MB), Olmesartan: Comprehensive vascular protection through targeted angiotensin II blockade
13. ↑ ^{a b} J. R. Siewert (2006), p. 447.

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !