What is Carotid Occlusive Disease?
The carotid arteries are blood vessels in the neck that supply blood to the brain. “Plaque,” or the buildup of fatty material, can result in narrowing, called a “stenosis” of the artery. Plaque particles that break lose are called “emboli, and these emboli can migrate to the brain, reducing its blood supply and resulting in a stroke.
What are the Symptoms of Carotid Disease?
The symptoms of carotid disease are the symptoms of a “mini-stroke” or “stroke.”
A “mini-stroke” is also called a “transient ischemic attack” (TIA), which is a reversible neurologic deficit resolving in less than 24 hours. This can manifest as loss of vision in one eye (amarosis fugax), paralysis, weakness, numbness, or tingling on one side of the body, or slurred speech. When these symptoms resolve in less than 24 hours, this is termed a “TIA,” which is a harbinger of a stroke. When the neurologic deficit is established, lasting longer than 24 hours, this is termed a “stroke.”
How do I know if I Have Carotid Occlusive Disease?
Risk factors that predispose a person to the development of carotid occlusive disease include high blood pressure, diabetes, smoking, high cholesterol, heart disease, and a family history of stroke. On physical examination, a physician may use a stethoscope and hear turbulent blood flow in the neck, called a “bruit.” If a bruit is heard, a duplex scan, essentially an ultrasound, of your carotid arteries will be obtained. This test is noninvasive, quick, and painless. It uses sound waves to detect the degree of carotid blockage. Other confirmatory studies include an MRI, or magnetic resonance imaging, and an angiogram. An MRA uses a magnet to detect a detailed image of the carotid artery, and usually is administered with intravenous contrast. The angiogram is the “gold-standard” study to confirm the degree of carotid blockage. It is invasive, and performed under X-ray imaging. It involves the placement of a needle, wire, and hollow tubes called sheaths and catheters, through the femoral artery in the groin, and the injection of contrast directly into the artery.
What is the Medical Management and Prevention of Carotid Occlusive Disease?
Reducing cholesterol levels, controlling diabetes and hypertension, exercising regularly, and cessation of smoking are cornerstones of treatment. The use of an “antiplatelet” medication, Aspirin (81 mg or 325 mg per day), has been shown to prevent stroke.
When do I Need Surgery for Carotid Occlusive Disease?
The purpose of carotid surgery is to prevent stroke. The risk of stroke increases with increasing degree of carotid stenosis. Numerous studies established the basis for when surgery is needed for carotid occlusive disease. The two widely accepted studies include the NASCET (North American Symptomatic Carotid Endarterectomy Trial), and the ACAS (Asymptomatic Carotid Artery Trial).
The NASCET Trial established that patients with symptoms (strokes or TIAs), had a higher stroke prevention rate with carotid surgery if they had greater that 70% carotid stenosis, in comparison to treatment with aspirin alone. Those with other risk high risk factors for a stroke, with a carotid stenosis between 50-69% also had a higher stroke prevention rate with carotid surgery, versus aspirin alone.
The ACAS Trial established that patients without symptoms had a greater stroke prevention rate with carotid surgery if they had a greater than 60% carotid stenosis, in comparison to treatment with aspirin alone.
What are the Options for Carotid Surgery?
Carotid endarterctomy and carotid stenting.
How is Carotid Endarterectomy Performed?
The operation can be performed under general or regional anesthesia. With general anesthesia, you are completely asleep, and placed on the ventilator. With regional anesthesia (a local anesthesia block of the neck), you are awake. A skin incision is made in the neck, along the course of the carotid artery, and control is obtained of the carotid arteries. You are given heparin, a blood thinner, and the arteries are clamped, opened, and plaque is removed. The artery is then usually reconstructed with a patch, and blood flow is reestablished to the brain, and the wound is closed. One can expect to be discharged the next day. If performed under regional anesthesia, the surgeon can continually assess your neurologic function. When performed under general anesthesia, a shunt may be placed in the artery to allow continual blood flow to the brain while the plaque is removed. Alternatively, a shunt does not have to be used if various adjunctive measures assess adequate blood flow to the brain, despite carotid clamping.
What are the Risks of Carotid Endarterectomy?
The risks include heart attack, bleeding, infection, stroke (1-3% in experienced hands at specialized centers), carotid re-blockage (1-21% range), and cranial nerve injury (occurs in about 16%, resulting in difficulty with speech, swallowing, lip corner droop, hoarseness, tongue deviation, and facial numbness).
What are the Advantages of Carotid Endarterectomy?
The main advantage is that is is a proven, durable procedure with established data in stroke prevention.
How is Carotid Stenting Performed?
Before the stenting procedure, you will begin taking aspirin and Plavix (Clopidigrol). With local anesthesia in the groin a needle puncture is made into the femoral artery, a wire is advanced into the aorta, and sheath (hollow tube) is inserted into the artery, and a catheter (long hollow tube) is directed into the carotid artery, all under X-ray guidance with the use of contrast agents. You are given heparin, and measurements are taken of the carotid artery to identify the correct filter basket and stent size. A filter basket attached to a wire, to capture emboli and is deployed into the carotid artery beyond the plaque. A stent (a flexible, wire mesh tube) is deployed at the site of the plaque. A balloon is inflated in the stent (angioplasty) to expand the stent fully, and then the balloon is removed. Sometimes, the balloon angioplasty needs to be performed prior to the stent deployment if a tight stenosis prevents stent passage. The filter basket with its captured emboli is reconstrained into a catheter and removed. A final image is obtained and a closure device is used to close the hole in the groin artery. After the procedure, you lye flat for several hours, your neurologic function is continuously monitored, and you are usually discharged the next day.
What are the Indications for Carotid Stenting?
Carotid stenting has limited indications. It has presently been approved by the Food and Drug Administration for the following use: patient who are symptomatic with > 50% carotid stenosis and who are high risk for carotid endarterectomy, and patients who are asymptomatic with a >80% carotid stenosis and who are high risk for carotid endarterectomy.
What are the Advantages of Carotid Stenting?
It can be performed under local anesthesia, requires no incisions, allows for a sooner full functional recovery, and causes no cranial nerve injury.
What are the Risks of Carotid Stenting?
Risks include stroke, puncture site bleeding, allergic dye reaction, hypotension (low blood pressure) kidney failure, arrhythmias (heart rhythm abnormalities), stent stenosis or thrombosis (clotting), heart attack and death.