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Of the 600,000 strokes that occur each year in the USA, it is estimated that 30-40% are caused by plaque in the carotid artery. This means that if the carotid artery plaque is discovered before a stroke occurs, the potential exists to prevent as many as 200,000 strokes annually.
Plaque accumulation in the carotid artery can be associated with symptoms or it may be silent ("asymptomatic"). Stroke may occur when a piece of plaque breaks free and travels to the brain or if the plaque in the carotid artery becomes so thick that it shuts down blood flow completely. Approximately 50% of people who suffer a stroke will die from the event and about 50% of the survivors have some permanent neurological deficit such as paralysis or inability to speak.
Another event that can occur due to plaque in the carotid arteries is a Transient Ischemic Attack (TIA). This is sometimes called a "mini stroke" but actually it is not a stroke.
Temporary weakness or numbness of an arm or leg (or both the arm and the leg on the same side of the body)
Temporary speech difficulty
Transient loss of vision in one eye (called transient monocular blindness or TMB)
When a person who has experienced a TIA is found on ultrasound exam to have a critical stenosis of the carotid artery, the risk of a stroke is thought to be about 30% during the next six months after the occurrence of the TIA. Surgery is recognized as the best option in such patients according to a widely accepted national prospective randomized study of this subject called the NASCET Trial.
Stenosis of the carotid artery is frequently silent and the plaque accumulation is discovered only because a physician has recommended an ultrasound examination of the neck as a "screening procedure". Patients who should be screened for carotid plaque are those with:
High cholesterol Coronary artery disease Previous Myocardial Infarction Diabetes Hypertension Peripheral vascular disease Family history of stroke
When plaque accumulation in the carotid artery has narrowed the artery by more than 80%, many vascular specialists will recommend that the plaque be removed. The advisability of surgery for this group of patients was proven by another prospective, randomized, national study called the ACAS Study. In most cases, the safest and most effective method for dealing with carotid artery plaque is by an operation called a carotid endarterectomy.
The decision to recommend surgery for any individual patient should be considered on a case by case basis by the physicians and surgeons who are treating that individual patient. Many factors should be considered in the decision making process. Not all patients need surgery. Some patients are best treated with medical management including statin therapy and anti-platelet therapy.
This operation is performed via a small incision on the side of the neck. The artery is opened and the plaque is removed. Frequently, the vascular surgeon will enlarge the artery by sewing a patch of vein or artificial material onto the artery after the plaque is removed. The operation is safe, extremely effective in preventing stroke and quite durable over the long-term in preventing stroke.
The success of this operation has been shown to be very dependent upon the experience of the surgeon. Results of operation vary from complication rates (meaning stroke during the operation itself) of 1-2% to as high as 10% with high volume surgeons having lower stroke rates than surgeons with a low volume of carotid surgery. In my own series of carotid operations in more than 1000 patients over a period of more than 20 years, the risk of stroke has been less than 1%. The average patient undergoing carotid endarterectomy is able to leave the hospital in one day. Recovery at home is rapid. Patients rarely have significant pain. Recurrence rates of carotid stenosis are very low-particularly if a vein patch is used to enlarge the carotid artery after the plaque is removed (see Video #2, Video #12).
Balloon angioplasty has been used in many arteries of the body including the femoral and iliac arteries of the leg and the coronary arteries of the heart. It was only a matter of time before it was tried in the carotid arteries. The procedure remains under investigation at this point and some of the surgeons who were initially enthusiastic about this procedure have had this enthusiasm tempered by less than satisfactory outcomes. It must be remembered that the balloon angioplasty and stent procedure is designed to crush plaque-NOT to remove it. Many strokes are considered to be caused by fragments of carotid artery plaque traveling from the neck to the brain. It would be expected that crushing a plaque with a balloon angioplasty and stent technique could lead to more fragments than the complete removal of a plaque from within the artery using meticulous surgical technique. Whereas a small piece of plaque traveling downstream from an angioplasty site may be easily tolerated in the leg or even the heart muscle, the consequences of such plaque fragmentation in the brain can be devastating. The standard carotid endarterectomy operation has been perfected to the point that most surgeons are reluctant to allow their patients to undergo the less successful carotid angioplasty/stenting procedure. Some vascular surgeons who routinely advise angioplasty/stenting of arteries in the abdomen, legs and heart will not advise carotid angioplasty/stenting. At this point in time carotid angioplasty/stenting is still an investigational procedure that must be compared with the carefully studied and clinically proven technique of carotid endarterectomy surgery. No long-term follow-up studies are available to permit a comparison of the durability of carotid angioplasty/stenting with carotid endarterectomy surgery.
A carotid artery dissection is a tear in the inner lining of the carotid artery that causes blood to flow between the layers of the artery wall. This reduces the size of the lumen of the artery and can reduce the amount of blood flowing to the brain. There is no bleeding into the neck with these tears because it occurs in the inner layer of the artery (there are three layers to each artery). A dissection can be caused by many things including direct trauma to the neck, twisting or hyperextending the neck, straining (as when lifting heavy weights), certain yoga positions, and chiropractic manipulations. A carotid artery dissection usually presents as pain in the neck, with or without headache. Often, but not always, there are neurologic symptoms consistent with a TIA or stroke. Most carotid artery dissections heal after treatment with anticoagulant medications such as heparin and warfarin ("Coumadin"). Surgery is rarely necessary. Although it has been tried, there is rarely a role for placing a stent into the carotid artery to treat a dissection. The diagnosis is established by studies such as carotid artery ultrasound, MRA (magnetic resonance angiogram), CTA (CT angiogram), or conventional angiography.