Carotid Artery Disease and Stroke Oxygenated blood is carried from the heart to the face and brain by the carotid arteries one on each side of the neck. The carotid arteries (common) bifurcate and become the internal carotid artery (ICA) and the external carotid artery (ECA). Blood supply to the brain is mainly through the internal carotid artery and the vertebral arteries (1). Blood flow to the brain is affected by carotid artery disease. Carotid artery disease is the narrowing (stenosis) or blockage (occlusion) of the carotid arteries.
Carotid artery disease is a common problem and a major cause of stroke. Carotid artery disease is caused by atherosclerosis (plaque) Atherosclerosis cannot be prevented, but the progression of the disease can be slowed or reduced through life style changes and diet (1). The best preventive measures are once again regular exercise, healthy diet, one that is low in cholesterol and saturated fat, maintaining a healthy body weight and not smoking (2). Factors that increase the risk of carotid artery disease: smoking, hypertension, diabetes, age, family hx, obesity, physical inactivity and high cholesterol (2).
The most serious complication of carotid artery disease is stroke. Carotid artery disease increases the risk of stroke by several means. • Reduced blood flow. A carotid artery may become so narrowed by atherosclerosis that not enough blood is able to reach portions of the brain. • Ruptured plaque. A piece of plaque may break off and flow to the brain (cerebral arteries). This fragment may get stuck in one of the smaller arteries, creating a blockage that cuts off blood supply to that area of the brain causing a stroke. • Blood clot blockage.
Some plaques are prone to cracking and forming irregular surfaces on the artery wall. When this happens, the body treats it like an injury and sends platelets to the area. A blood clot can develop and block or slow the flow of blood through a carotid or cerebral artery, causing a stroke. A stroke can leave a patient with permanent brain damage and muscle weakness. In severe cases, it can be fatal (3). To diagnose carotid artery disease, a physician may use a stethoscope to listen to the carotid arteries to detect a bruit (sound caused by turbulent flow in a narrowed artery).
Depending on the results of patient history and the physical examination the doctor may order the following test: Carotid duplex ultrasound: transcranial Doppler ultrasound, CT scan, an MRA or arteriography (3) The main goal of treating carotid artery disease is to prevent a stroke. The method of treatment depends on how narrow the arteries have become. In mild to moderate cases, simple lifestyle changes and medications may be sufficient to prevent stroke. If the blockage is severe or the patient has experienced a TIA or stroke, surgery or a stenting procedure may be necessary (4).
Medications: a daily aspirin or another blood-thinning medicine may be prescribed to prevent the formation of dangerous blood clots. ACE inhibitors, or calcium channel blockers may be used to control hypertension and a statin medication to lower cholesterol (4). Procedures: when narrowing of a carotid artery is severe, or if the patient has had a stroke, it is common practice to open up the artery and remove the blockage. There are two ways to do this (3). • Carotid endarterectomy. This is the most common treatment for severe carotid artery disease.
This procedure is done under either local or general anesthesia. After making an incision along the front of the neck, the surgeon opens the affected carotid artery and removes the plaque. The artery is repaired with either stitches or a graft. Most people are discharged from the hospital within 48 hours after the operation. The risks are low, even in adults over 80 years old, as long as they are in good health. Studies have also shown that this type of surgery has lasting benefits and helps prevent strokes (3). When a carotid endarterectomy isn’t feasible due to the location of the blockage or when the patient’s condition, may make surgery too risky. A balloon procedure called carotid angioplasty and stenting may be performed (3). There are no specific symptoms to carotid artery disease. Unfortunately, a stroke is often the first or only symptom of carotid artery disease. Transient ischemic attacks (TIAs) are the most important warning sign a patient may be on the verge of a stroke. However, not everyone who has a stroke experiences a (TIA) (2).
A (TIA) is an episode of temporary cerebral dysfunction caused by impaired blood flow to the brain. Symptoms of transient ischemia attack (TIA) are: Partial loss of vision in one eye, weakness, tingling, or numbness that happens without any apparent cause, on one side of the body or in one arm or leg, loss of control of movement of one arm or leg and trouble with speech (2). Transient ischemic attacks can last anywhere, from a few minutes, to a couple of hours and rarely last more than 24 hours (2).
A cerebrovascular accident (CVA), also called a stroke or brain attack happens when the blood supply to part of the brain is blocked or when a blood vessel burst (aneurysm) causing brain damage. When blood flow to the brain is impaired oxygen and glucose cannot be delivered (2). The adult brain represents two percent of total body weight, but consumes more than twenty percent of the oxygen and glucose used even during rest. When blood flow to the brain is interrupted neural functions are impaired. Deprivation of four minutes or more can cause permanent damage and even a brief slowing can cause unconsciousness (3).
Strokes are the third leading cause of death in the United States. Among the survivors, strokes can cause significant disability including paralysis along with speech and emotional problems (5) The symptoms that follow a stroke depend on the area of the brain that was affected and the magnitude of damage. Small strokes may not have any symptoms but still damage brain tissue; this type of stroke is referred to as a silent stroke. According to The U. S. National Institute of Neurological Disorders and Stroke (NNDS) the five major signs of stroke are (5). ). Sudden numbness or weakness of the face, arm or leg, especially on one side of the body 2). Sudden confusion or trouble speaking or understanding. 3). Sudden trouble seeing in one or both eyes. 4). Sudden trouble walking, dizziness, loss of balance or coordination. 5). Sudden sever headache with no known cause. Strokes are classified as either Ischemic strokes (when the brain is not getting enough blood) or hemorrhagic stroke (too much blood within the skull). Strokes can be caused by a variety of reason other than carotid artery disease.
Narrowing of the small arteries in the brain, embolism from the heart, cerebral hemorrhage caused by hypertension, subarachnoid hemorrhage, vasculitis and migraine headache (4) • Risk factors: family history of stroke, heart attack or TIA, age (55;) hypertension, smoking, diabetes, obesity, high cholesterol, cardiovascular disease, previous stroke or TIA, use of birth control pills, heavy binge drinking and cocaine. Although men and women have strokes at about the same rate, women often die of strokes more than men do.
Blacks are more likely to have strokes than people of other races (5). Before treating a stroke it must first be decided what type of stroke the patient is having and what part of the brain is being affected. This can be accomplished using the following methods: carotid ultrasound, arteriography, CT, MRI, and physical examination. These methods are also used for screening at risk patients (4). Treatment depends on what type of stroke the patient is experiencing. Ischemic stroke, blood flow to the brain must be restored quickly. Clot busting therapy must start within three hours (4).
Aspirin is the best-proven treatment immediately following a stroke to reduce the chance of having another stroke (4). Warfin, Coumadin and heparin may be given, but they are not used as commonly as aspirin. An injection of tissue plasminogon activator (clot buster) has shown some recovery benefit to patients but cannot be used with patients who are having a hemorrhagic stroke (4). Carotid endarterectomy or angioplasty and stents may be performed to open up the carotid arteries and return blood flow to the brain (5). Hemorrhagic stroke usually require some type of surgery.
The most common procedures done are aneurysm clipping and arteriovenous malformation removal (AVM) and coiling. Aneurysm clipping: A small clamp is placed at the base of the aneurysm, cutting it off from circulation. This may keep the aneurysm from bursting. The clip stays in place permanently (4). Aneurysm embolization: A catheter is positioned into the aneurysm and a small coil is pushed inside the catheter. The coil fills the aneurysm causing the blood to clot and sealing off the aneurysm (4) Surgical AVM removal: this procedure can only be done on small, superficial vessels that are easily accessible.
This procedure has proven to eliminate the risk of rupture and thereby lowering the overall risk of hemorrhagic stroke (4) There is much to be learned about strokes, carotid artery and coronary disease. There is a link between the three, along with the other pathologies we have already discussed. As a student I am learning how these diseases mimic one another along with how they differ. I see the importance of knowing the diseases and my role in being able to distinguish them. Citation Page 1). Arger, P (2004). The Complete Guide to Vascular Ultrasound. Philadelphia, PA: Lippincott Williams & Wilkins. Lyoob, 2004). 2. ) Tortora, G (2006). Principles of Anatomy and Physiology. Hoboken, NJ: John Wiley and Sons. (Derrickson, 2006). 3). (2008, December 10). MedicineNet. Retrieved September 7, 2009, from Carotid Artery Disease Web site: http://www. medicinenet. com. 4). 2009, March 05). MedicineNet. Retrieved September 7, 2009, from Stroke Causes, Symptoms, Diagnosis and Treatment Web site: http://www. medicinenet. com/Stroke. html. 5). (2009, August 07). NNDS Disorders. Retrieved September 7, 2009, from Stroke Web site: http://www. nnds. nih. gov/disorders/stroke. html