What is Carotid disease?
Carotid disease arises from the development of plaque along the line of the carotid arteries. There are two carotid arteries in the neck and two vertebral arteries. These are the four arteries which supply blood to the brain. When plaque becomes extremely narrow it can lead to blockage and then stroke. The plaque can also rupture, and the resultant debris can be deposited in the blood stream and flow to the brain can be limited causing stroke.
Occasionally in association with plaque disease there can be aneurysmal change of the carotid artery.
Why is Carotid disease a problem?
Carotid disease is a problem because it can lead to stroke either from blockage of the carotid artery or as a result of plaque rupture. The debris from plaque rupture enters the blood stream and can cause a stroke or what is known as a transient ischaemic attack. A transient ischaemic attack is when a temporary occlusion of blood supply to the brain occurs causing a temporary stroke. The blood supply recovers and the stroke resolves. A stroke, itself, is a fixed deficit, in other words a permanent weakness of arm, leg or visual symptoms and this can be a severe stroke or a minor stroke.
The deficit resulting from a stroke in the carotid territory includes arm or leg paresis, loss of speech, loss of brain function resulting in black outs and there is also the possibility of visual loss on the troublesome side. This visual loss can be transient or permanent.
Stroke can be associated with death and can leave permanent deficits such as outlined above.
How is Carotid disease detected?
Commonly, examination of the neck will reveal what is a called a bruit. This is the noise made by turbulent blood flow passing through a narrow carotid artery. This can be picked up with a stethoscope leading to investigation with ultrasound and occasionally MRA and CT-angiogram.
Symptoms also lead to investigation and these symptoms can be either of a transient stroke (TIA) or fixed mild stroke.
The symptoms of TIA/stroke are:
- Arm weakness
- Leg weakness
- Facial droop
- Loss of vision in one eye
- Drop attack
- Disturbance of speech
What predisposes to Carotid disease?
- Age (over 70)
How is it prevented?
Risk factor control
- Cessation of smoking
- Control diabetes
- Control hypertension
- Control hyperlipidemia
How is it treated?
- Risk factor control
- Antiplatelet medication (Aspirin, Plavix)
- Anti-coagulation (Warfarin, Eliquis etc)
- Carotid Surgery (Carotid stent, Carotid endarterectomy)
When to choose carotid endarterectomy or carotid stenting?
The aim of all carotid surgery be it endarterectomy or stent is to prevent stroke.
In the setting of a minor stroke, transient stroke or very tightly narrowed carotid artery, then carotid surgery may be appropriate. There are two options, namely endarterectomy where the artery is cleaned out by open surgery or stent where the plaque is stabilised by introduction of a stent into the flow channel. The endarterectomy is open surgery requiring anesthetic, the stent is local anesthetic and sedation, with a stent being introduced via a needle puncture in the groin (femoral artery).
Both procedures have the benefit of preventing stroke and both carry the small risk of a stroke at the time of surgery. In the case of endarterectomy, the risk is about 2% of cases in the carotid stent the situation is 4%.
The open procedure with endarterectomy is usually reserved for patients with a good cardiac, respiratory and renal function, whereas stenting is more applicable to patients with significant coincidental illness, particularly of a cardiac nature, respiratory nature or if the carotid disease has been a consequence of radiation to the neck or there has been a previous carotid endarterectomy, with renarrowing of artery.
What is carotid endarterectomy?
This is a surgical procedure to clear plaque from the carotid artery and repair the artery. It is usually performed under general anesthetic but can be performed under local anesthetic and the plaque is usually situated at the midpoint of the neck near the angle of the jaw. An oblique incision is made in the neck, the artery that contains the plaque is displayed and it is important to preserve the function of the nerves surrounding the carotid artery. The artery is then clamped and opened. Sometimes a shunt is used to maintain blood supply during the procedure, but often, this is not necessary. Plaque is then removed; the artery is repaired and the incision in the artery is then closed with a fabric patch to maximise patency and minimise the chance of post-operative narrowing of the artery. The neck incision is then closed, and a drain tube is placed in the wound.
What can be expected post operatively?
You will be returned to the vascular ward. The nurses will undertake observations for blood pressure pulse rate, neurological state and inspect for hematoma in the neck. The following day the drain tube will be removed, observations will continue, but you should be able to get out of bed and walk and start resuming normal activities the following day. You will be home on day two or three post operatively provided neck wound and blood pressure is stable and neurologically all is well.
You will be able to resume a full range of activities at about 2 – 3 weeks and that includes driving, but in the intervening period you will be able to relax at home without much in the way of discomfort in the neck. There may be a little numbness on the inside of the neck wound, which will resolve in time.
Are there any changes to be expected?
Because of the incision there will be a scar. The scar will be thickened in the first few months and then will resolve to be a mature fine white line. There will be some numbness in the neck, as mentioned above, but this will diminish although it will probably leave you will a small area of numbness immediately in the front of the scar in the middle of the neck, but this is of no great consequence. In the early days there will be some mild wound swelling, but this will resolve.
What are the major complications?
- Hematoma in the neck to some degree occurs in 1-2% of patients. In a small percentage of these patients the hematoma needs surgical drainage.
- Stroke – Stroke rate is a less than 2% for this procedure.
What is a carotid stent?
A carotid stent is a metal scaffold (usually Nitinol) which is placed within the flow channel of the artery to push aside the plaque and maintain a channel. It stablises the plaque, however it does not remove the plaque. The stent is delivered to the carotid artery via a femoral artery puncture (in the groin). A catheter and wire are introduced from the groin to the neck, a sheath is positioned in the carotid artery just below the plaque and then a filter (like an umbrella) is passed through the flow channel in the narrowed plaque and positioned beyond the plaque to catch any debris, which may be released when the plaque is balloon dilated and stented.
With the umbrella in place, the plaque is then balloon dilated to open the channel and this balloon dilation is then supported with a stent, which is further ballooned. The balloon is then removed, the stent remains in place permanently and the umbrella is retrieved.
The puncture site in the groin is then plugged with an angioseal closure device. The positioning of the stent is undertaken under radiological control. The procedure needs to be performed in a special radiological based operating theatre.
What can I expect after the procedure?
You will go back to the vascular ward. Observations will be made regarding blood pressure, pulse rate, hematoma in the groin and neurological changes. If all is well and blood pressure is well maintained you will be able to go home 48 hours after the procedure. If blood pressure is not quite stable or neurological changes, or a groin hematoma occurs then a hospital stay will be required until the issue is resolved.
What are the major complications of a carotid stent?
The major complication is stroke, with a rate of approximately 4%, groin hematoma of approximately 1% and death is rare.