Carotid Artery Stenting

A pair of carotid arteries course through the neck and supply the majority of blood to the brain. Narrowing of these arteries increases the risk of stroke.

There are currently two therapies for this problem. Traditionally, a surgeon operates on the neck, exposes the artery, temporarily clamps it off and removes the diseased lining before closing the artery and re-establishing blood flow (endarterectomy). More recently carotid stenting is proving to be an alternative therapy. This involves placing a metal scaffold within the artery to keep it open. In some instances carotid stenting may be the preferred treatment.

Before the procedure your doctor will commence you on a drug called Clopidogrel which acts on the blood constituents which normally cause clotting (platelets). Aspirin is also prescribed for the same reason if you are not already taking it. Both of these drugs work in tandem to reduce the risk of clotting during the procedure and within the stent afterward (thrombosis) and thereby reduces the risk of stroke.

The procedure is performed under sedation with an anaesthetist in attendance and usually takes a 1-2 hours. A slightly larger tube is placed in the groin allowing the stent to be passed through. The neuroradiologist passes a very fine wire (microwire) with an attached umbrella like protection device through the narrowing. This acts to catch any material that enters the vessel during stent placement and vessel balloon dilatation. The narrowing may first be dilated to allow easier passage of the stent. You may feel some mild discomfort as the balloon is inflated for a short time. The metallic stent is then accurately positioned across the region of narrowing and deployed. Another balloon may then be passed within the stent to open it up further.

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Before treatment After treatment Metallic stent in place

Complications are as described for diagnostic cerebral angiography although the risk of stroke is slightly increased due to the necessity of passing catheters and guide wires through a diseased artery and stretching the diseased artery with a balloon and stent.

The carotid artery contains some sensors which detect pressure (baroreceptors). Some people are more sensitive than others when this area is stretched by the balloon or stent resulting in a slowing of the heart-rate (bradycardia) and reduction in blood pressure (hypotension). This is usually treated with medication but in rare cases a temporary pacemaker may need to be inserted. Typically if this problem occurs it settles within days of the stent being placed.

Another potential (albeit very rare) problem that may occur results from the marked increase in blood flow to the brain following stent placement. This is known as reperfusion injury and occurs due to a malfunction in the way the blood vessels of the brain cope with increased blood flow as they have been used to much less blood getting through for a long time. This problem is uncommon but may result in swelling of the brain (cerebral oedema) and less often hemorrhage within the brain which is potentially very serious.

After the procedure you will be transferred to intensive care for close observation over the next day. The groin sheath is subsequently removed and you will be transferred to the ward for another day or two before going home.

Important note for patients treated with carotid stenting:
You should avoid excessive pressure on your neck where the stent has been placed. This should be brought to the attention of the operator when you have an ultrasound scan of the neck and therapists such as chiropractors, masseurs and physiotherapists.

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