Introduction
Carotid stenting is an alternative method of treating atherosclerotic plaque in the carotid artery. Similar to stents used in the peripheral arteries, the carotid stent compresses the plaque into the arterial wall and then acts as a scaffold to keep the artery open. It is a less invasive (keyhole) procedure, however there is a risk of dislodging plaque with the stent, which can travel up to the brain, so in most situations carotid stenting is reserved for patients where surgery is considered too high risk.
Indications
As for carotid endarterectomy, the aim of Carotid Stenting is to reduce the risk of stroke. There are 2 main indications for the surgery:
- Patients having symptoms from the carotid stenosis
- Stroke – arm or leg weakness, facial droop, speech difficulties
- Transient Ischaemic Attack– the same symptoms of stroke but recovering in <24 hours
- Visual Loss (Amaurosis Fugax) – the temporary or permanent loss of vision form the eye on the same side as the stenosis.
- Asymptomatic (No Symptoms) Severe Stenosis.
Carotid stenting is mainly considered in patients unsuitable for carotid surgery. This may be due to other medical conditions (e.g. severe heart disease), previous neck surgery or radiation treatment.
Preoperative Instructions
Carotid stenting is generally performed under Local Anaesthesia with sedation. This allows ongoing neurological monitoring during the procedure. Most patients will be admitted the day prior surgery to assess Blood pressure and review of medications.
The decision to proceed with treatment will depend on Ultrasound imaging, Ct Angiography and the types of symptoms present.
Procedure
The procedure involves performing angiography form an arterial puncture in the groin. Ultrasound is used to guide the puncture and a tube is then placed into the artery to allow contrast (X-ray dye) injection.
Images of the carotid artery, the plaque and the blood flow into the brain are obtained. After the administration of strong blood thinners, a small guide wire is passed through the plaque into the normal artery above the plaque. A small filter is then placed above the plaque to capture any material if it should be dislodged.
Balloon Angioplasty is performed to pre-dilate the artery to ensure the stent will adequately expand. A self-expanding (spring like) stent is then deployed over the plaque and further ballooning to ensure adequate positioning is performed. Further angiographic images are obtained to ensure adequate blood flow is restored.
The groin puncture is then usually closed with a device that places a clip or suture into the artery and the patient transferred to the intensive care unit for further monitoring.
Postoperative Instructions
Postoperative care is performed in the intensive care unit for the first 24 hours. This allows careful monitoring of blood pressure and neurological status. On day following the procedure the patient will be transferred to the ward to mobilise and return to usual activities. Most patients will be discharged on day 2 after the procedure.
Risks
As with all procedures, there are risks associated with carotid stenting. The main concern is neurological events such as stroke.
The potential complications include:
- Bleeding – bleeding from the puncture site in the groin may occur following stenting procedures. This can usually be managed with simple measures, however in severe situations, surgical treatment to repair the artery may be required.
- Stoke – the aim of carotid stenting is to prevent stroke. There is a small risk of stroke from this procedure. This may occur due to dislodging plaque during passage of the wire through the plaque or during ballooning or stent deployment. Stroke following stenting can be very minor with full recovery or a severe disabling stroke. Symptoms can include arm or leg weakness, speech difficulty or visual loss. In severe cases there is a risk of life-threatening damage.
- Cardiac Complications – carotid stenting can cause fluctuations of blood pressure This in turn can cause some cardiac stress with the risk of a heart attack developing.
- Intra-cranial Haemorrhage – this is a very rare complication and can develop if the blood pressure is too high. Treating the plaque does increase the blood flow to the brain tissue on that side which can pose a risk of bleeding, particularly if a previous large stroke has occurred.
- Re-Narrowing – whilst uncommon, it is possible that the treated artery can re-narrow over time. This can be due to more plaque development or due to scarring at the site of the surgery. Most re-narrowing is treated with medications, however re-operation may occasionally be required.
Treatment Alternatives
The options to treat carotid artery disease are:
- Medical therapy – blood thinners, cholesterol medications, blood pressure and diabetic control are all critical in the management of carotid disease.
- Carotid Endarterectomy – surgical removal of the carotid plaque is generally recommended in symptomatic patients and those with a severe carotid stenosis.
- Carotid Stenting – an alternative to endarterectomy and usually reserved for high risk patients or those unsuitable for carotid surgery.