Place two fingers on the side of your neck– when you feel a pulse, you’ve located your carotid arteries. These arteries are the main route by which blood is carried to the brain--they branch off a short distance away from the heart and extend upwards through the neck, carrying oxygen-rich blood. Unfortunately, the vital roles of the carotid arteries leave them vulnerable to serious afflictions, such as carotid artery disease or carotid artery stenosis (the narrowing of the carotid arteries).
A blockage in the carotid arteries can also have severe consequences such as stroke. Such obstructions can be caused by atherosclerosis– a disease of the blood vessels in which fatty substances, cholesterol, cellular waste products, calcium and fibrin build up in the inner lining of an artery to form plaque, hardening the artery and causing a blockage. These can not only lead to a heart attack, but also reduce the supply of oxygen and nutrients to the brain.
If the narrowing of the carotid arteries becomes severe enough to block blood flow, or if a piece of artery plaque breaks off and obstructs blood flow to the brain, brain cells will begin to die after just a few minutes without blood or oxygen, causing a stroke.
Blocked or narrowed carotid arteries can be treated through a process called a carotid angioplasty. First performed in 1980 by Dr Sean F. Mullan of the University of Chicago, the carotid angioplasty is a less invasive alternative to a carotid endarterectomy, which requires the artery to be surgically opened.
A carotid angioplasty, on the other hand, only involves making a small puncture in the groin. A special catheter with a tiny balloon at its tip is inserted into the carotid artery to be treated, and the balloon is inflated once the catheter has been placed into the narrowed area of the artery. The inflation of the balloon compresses the fatty tissue in the artery and makes a larger opening inside the artery for improved blood flow. A tiny expandable metal coil, known as a stent, may be inserted into the newly opened area of the artery to help keep the blood vessel from narrowing or closing again.
As with any surgical procedure, a carotid angioplasty does carry some risk: Clots can potentially dislodge from the plaque built up in the carotid arteries, move into the circulation of the brain and possibly cause a stroke during the operation. Embolic prevention devices, some with a filter-like basket attached to a catheter, are therefore positioned in the artery during a carotid angioplasty to catch any clots or small debris that might break loose from the plaque, thereby helping to reduce the incidence of stroke while the patient is in surgery.
The only setback is that not many neurologists believe that stenting works. There are many patients with severely narrowed carotid arteries who are simply being sent home with drugs. Such attitudes towards carotid angioplasties will only worsen a patient’s condition
Statistics demonstrate that a carotid angioplasty is in fact a fairly low-risk procedure—in 1993, its immediate success rate in North America already exceeded 80 per cent, while its stroke and mortality rate remained low at nine per cent. A later study conducted in 1996 by Dr G.S. Roubin revealed that out of 238 carotid angioplasties, the mortality rate was only 0.5 per cent, the major stroke rate was one per cent, and the minor stroke rate was 7.4 per cent.
The carotid angioplasty has always been a high-risk procedure. The risk is in the range of below 5 per cent, in that someone may get a stroke and other associated conditions such as a dramatic drop in blood pressure or a heart attack during the carotid angioplasty. Patient usually remains conscious during the procedure, though under a local anaesthetic, and will not be allowed to bend their leg nearest the insertion site (if the insertion is done in the groin) for several hours.
However, the relative lack of invasiveness during the procedure means that a patient who has undergone a carotid angioplasty may be discharged from hospital after two nights’ admission, depending on their progress.
There is usually no discomfort, except the patient has to lie flat until their groin is better. There should be no neck pain, although some patients may feel some discomfort at the site of the neck where the stent was placed. Aftercare mainly involves monitoring a patient’s blood pressure until their condition stabilises. They may also be prescribed double antiplatelets for one month.
HeartTalk Issue No 4
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