Carotid endarterectomy | |
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ICD-9-CM | 38.1 |
MeSH | D016894 |
Carotid endarterectomy is a surgical procedure used to reduce the risk of stroke from carotid artery stenosis (narrowing the internal carotid artery). In endarterectomy, the surgeon opens the artery and removes the plaque. The plaque forms and thickens the inner layer of the artery, or intima, hence the name of the procedure which simply means removal of part of the internal layers of the artery.
An alternative procedure is carotid stenting, which can also reduce the risk of stroke for some patients.
Carotid endarterectomy is used to reduce the risk of strokes caused by carotid artery stenosis over time. Carotid stenosis can either have symptoms (i.e., be symptomatic), or be found by a doctor in the absence of symptoms (asymptomatic) - and the risk-reduction from endarterectomy is greater for symptomatic than asymptomatic patients.
Carotid endarterectomy itself can cause strokes, so to be of benefit in preventing strokes over time, the risks for combined 30-day mortality and stroke risk following surgery should be < 3% for asymptomatic people and ≤ 6% for symptomatic people. [1]
Carotid endarterectomy does not treat symptoms of prior strokes. It is controversial if carotid endarterectomy can improve cognitive function in some patients. [2]
Symptomatic people have had either a stroke or transient ischemic attack or amaurosis fugax.
In symptomatic patients with a 70–99% stenosis, for every six people treated, one major stroke would be prevented at two years (i.e., a number needed to treat of six). [3]
Unlike asymptomatic patients, symptomatic people with moderate carotid stenosis (50–69%) still benefit from endarterectomy, albeit to a lesser degree, with a number needed to treat of 22 at five years. Recent evidence demonstrated that unstable carotid atherosclerotic plaques are responsible for cerebral ischemic events and symptoms (stroke or transient ischemic attack) in these patients. [4] [5] In addition, co-morbidity adversely affects the outcome: people with multiple medical problems have a higher post-operative mortality rate and hence benefit less from the procedure. For maximum benefit people should be operated on soon after a stroke or transient ischemic attack, preferably within the first 2 weeks. [3]
Asymptomatic people have narrowing of their carotid arteries, but have not experienced a transient ischemic attack or stroke. The annual risk of stroke in patients with asymptomatic carotid disease is between 1% and 2%, although some patients are considered to be at higher risk, such as those with ulcerated plaques. This low rate of stroke means that there is less potential stroke risk-reduction from endarterectomy for asymptomatic patients relative to symptomatic patients. However, for asymptomatic patients with severe carotid stenosis (80-99%), carotid endarterectomy plus treatment with a statin medicine and anti-platelet therapy does reduces stroke risk further than medication alone in the five years following surgery. [6]
The most feared complication of carotid endarterectomy is stroke. Risks of stroke at the time of surgery are higher for symptomatic (3–5%) than asymptomatic patients (1–3%). [7]
Bleeding, infection, and cranial nerve injury are also risks at the time of surgery. Following surgery, a rare early complication is cerebral hyperperfusion syndrome, also known as reperfusion syndrome, which is associated with headache and high blood pressure following surgery.
Long term complications include restenosis of the endarterectomy bed, although the clinical significance of this is controversial in asymptomatic patients.
The procedure should be avoided when:
High risk criteria for carotid endarterectomy include the following:
Carotid artery stenting is an alternative to carotid endarterectomy in cases where endarterectomy is considered too risky.
An incision is made on the midline side of the sternocleidomastoid muscle. The incision is between 5 and 10 cm (2.0 and 3.9 in) in length. The internal, common and external carotid arteries are carefully identified, controlled with vessel loops, and clamped. The lumen of the internal carotid artery is opened, and the atheromatous plaque substance removed. The artery is closed using suture with or without a patch to increase the size of the lumen. Hemostasis is achieved, and the overlying layers closed with suture. The skin can be closed with suture which may be visible or invisible (absorbable). Many surgeons place a temporary shunt to ensure blood supply to the brain during the procedure. The procedure may be performed under general or local anaesthesia. The latter allows for direct monitoring of neurological status by intra-operative verbal contact and neurological assessment. [8] With general anaesthesia, indirect methods of assessing cerebral perfusion must be used. Electroencephalography (EEG), transcranial doppler analysis, cerebral oximetry, or carotid artery stump pressure monitoring can guide the placement of a shunt, or a shunt may be routinely used. At present there is still ongoing debate related to difference in outcome between local and general anaesthesia, and methods of determining the need for a shunt. [3] However, excellent outcomes can be achieved by performing carotid endarterectomy under local local anaesthesia. [9]
The endarterectomy procedure was developed and first done by the Portuguese surgeon Joao Cid dos Santos in 1946, when he operated an occluded subsartorial artery, at the University of Lisbon. In 1951 an Argentinian surgeon repaired a carotid artery occlusion using a bypass procedure. The first endarterectomy was successfully performed by Michael DeBakey around 1953, at the Methodist Hospital in Houston, TX, although the technique was not reported in the medical literature until 1975. [10] The first case to be recorded in the medical literature was in The Lancet in 1954; [10] [11] the surgeon was Felix Eastcott, a consultant surgeon and deputy director of the surgical unit at St Mary's Hospital, London, UK. [12] Eastcott's procedure was not strictly an endarterectomy as we now understand it; he excised the diseased part of the artery and then resutured the healthy ends together.[ citation needed ] Carotid endarterectomy was finally shown to be effective in stroke prevention after a landmark clinical trial [13] spearheaded by the Canadian clinical scientist Dr. Henry Barnett. Since then, evidence for its effectiveness in different patient groups has accumulated. In 2003 nearly 140,000 carotid endarterectomies were performed in the US, however, the number of procedures has continued to decrease over time. [14]
A transient ischemic attack (TIA), commonly known as a mini-stroke, is a minor stroke whose noticeable symptoms usually end in less than an hour. A TIA causes the same symptoms associated with a stroke, such as weakness or numbness on one side of the body, sudden dimming or loss of vision, difficulty speaking or understanding language, slurred speech, or confusion.
Angioplasty, also known as balloon angioplasty and percutaneous transluminal angioplasty (PTA), is a minimally invasive endovascular procedure used to widen narrowed or obstructed arteries or veins, typically to treat arterial atherosclerosis.
Cerebrovascular disease includes a variety of medical conditions that affect the blood vessels of the brain and the cerebral circulation. Arteries supplying oxygen and nutrients to the brain are often damaged or deformed in these disorders. The most common presentation of cerebrovascular disease is an ischemic stroke or mini-stroke and sometimes a hemorrhagic stroke. Hypertension is the most important contributing risk factor for stroke and cerebrovascular diseases as it can change the structure of blood vessels and result in atherosclerosis. Atherosclerosis narrows blood vessels in the brain, resulting in decreased cerebral perfusion. Other risk factors that contribute to stroke include smoking and diabetes. Narrowed cerebral arteries can lead to ischemic stroke, but continually elevated blood pressure can also cause tearing of vessels, leading to a hemorrhagic stroke.
Vascular surgery is a surgical subspecialty in which vascular diseases involving the arteries, veins, or lymphatic vessels, are managed by medical therapy, minimally-invasive catheter procedures and surgical reconstruction. The specialty evolved from general and cardiovascular surgery where it refined the management of just the vessels, no longer treating the heart or other organs. Modern vascular surgery includes open surgery techniques, endovascular techniques and medical management of vascular diseases - unlike the parent specialities. The vascular surgeon is trained in the diagnosis and management of diseases affecting all parts of the vascular system excluding the coronaries and intracranial vasculature. Vascular surgeons also are called to assist other physicians to carry out surgery near vessels, or to salvage vascular injuries that include hemorrhage control, dissection, occlusion or simply for safe exposure of vascular structures.
Stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke:
Amaurosis fugax is a painless temporary loss of vision in one or both eyes.
Henry Joseph Macaulay Barnett, known by his colleagues and friends as "Barney", was a Canadian physician and neurologist. He was also a leading clinical stroke researcher as a result of being the principal investigator in several major clinical trials. As a clinical scientist, he did pioneering research in stroke prevention, beginning with the use of aspirin.
Carotid artery stenosis is a narrowing or constriction of any part of the carotid arteries, usually caused by atherosclerosis.
Cerebral infarction, also known as an ischemic stroke, is the pathologic process that results in an area of necrotic tissue in the brain. In mid to high income countries, a stroke is the main reason for disability among people and the 2nd cause of death. It is caused by disrupted blood supply (ischemia) and restricted oxygen supply (hypoxia). This is most commonly due to a thrombotic occlusion, or an embolic occlusion of major vessels which leads to a cerebral infarct. In response to ischemia, the brain degenerates by the process of liquefactive necrosis.
Vertebrobasilar insufficiency (VBI) describes a temporary set of symptoms due to decreased blood flow (ischemia) in the posterior circulation of the brain. The posterior circulation supplies the medulla, pons, midbrain, cerebellum and supplies the posterior cerebellar artery to the thalamus and occipital cortex. As a result, symptoms vary widely depending which brain region is predominantly affected.
A watershed stroke is defined as a brain ischemia that is localized to the vulnerable border zones between the tissues supplied by the anterior, posterior and middle cerebral arteries. The actual blood stream blockage/restriction site can be located far away from the infarcts. Watershed locations are those border-zone regions in the brain supplied by the major cerebral arteries where blood supply is decreased. Watershed strokes are a concern because they comprise approximately 10% of all ischemic stroke cases. The watershed zones themselves are particularly susceptible to infarction from global ischemia as the distal nature of the vasculature predisposes these areas to be most sensitive to profound hypoperfusion.
Fibromuscular dysplasia (FMD) is a non-atherosclerotic, non-inflammatory disease of the blood vessels that causes abnormal growth within the wall of an artery. FMD has been found in nearly every arterial bed in the body, although the most commonly affected are the renal and carotid arteries.
A Hollenhorst plaque is a cholesterol embolus that is seen in a blood vessel of the retina. It is usually found when a physician performs ophthalmoscopy, during which a plaque will appear as a small, bright crystal that is refractile and yellow. This is a medical exam finding, and is not a medical condition, though it may be related to cardiovascular conditions such as atherosclerosis of the internal carotid artery. It was first described by American ophthalmologist Robert Hollenhorst in 1961.
Carotid artery dissection is a serious condition in which a tear forms in one of the two main carotid arteries in the neck, allowing blood to enter the artery wall and separate its layers (*dissection*). This separation can lead to the formation of a blood clot, narrowing of the artery, and restricted blood flow to the brain, potentially resulting in stroke. Symptoms vary depending on the extent and location of the dissection and may include a sudden, severe headache, neck or facial pain, vision changes, a drooping eyelid, and stroke-like symptoms such as weakness or numbness on one side of the body, difficulty speaking, or loss of coordination.
Carotid artery stenting is an endovascular procedure where a stent is deployed within the lumen of the carotid artery to treat narrowing of the carotid artery and decrease the risk of stroke. It is used to treat narrowing of the carotid artery in high-risk patients, when carotid endarterectomy is considered too risky.
The leptomeningeal collateral circulation is a network of small blood vessels in the brain that connects branches of the middle, anterior and posterior cerebral arteries, with variation in its precise anatomy between individuals. During a stroke, leptomeningeal collateral vessels allow limited blood flow when other, larger blood vessels provide inadequate blood supply to a part of the brain.
Andrew Nicolaides is a British-Greek Cypriot surgeon, and an expert in cardiovascular disease and stroke prevention.
John David Spence is a Canadian medical doctor, medical researcher and Professor Emeritus at the University of Western Ontario. He is affiliated with the University of Western Ontario and the Robarts Research Institute, one of Canada's leading medical research organizations. Before his retirement from clinical practice in July 2022, he was also affiliated with the London Health Sciences Centre's University Hospital. He is a recognized expert in stroke prevention and stroke prevention research, with more than 600 peer-reviewed publications since 1970. He delivered more than 600 lectures on stroke prevention in 42 countries. In 2015, he received the Research Excellence Award from the Canadian Society for Atherosclerosis, Thrombosis and Vascular Biology. In 2019, he was appointed a Member of the Order of Canada, and in 2020 he received the William Feinberg Award from the American Heart Association for excellence in clinical stroke research.
Embolic stroke of undetermined source (ESUS) is an embolic stroke, a type of ischemic stroke, with an unknown origin, defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic sources. As such, it forms a subset of cryptogenic stroke, which is part of the TOAST-classification. The following diagnostic criteria define an ESUS:
Brajesh K. Lal, born in 1963 in Varanasi, India and of Indian origin, is an American surgeon, and an expert in vascular disease, particularly the prevention and treatment of stroke and venous disease. He is a tenured Professor of Vascular Surgery at the University of Maryland and Professor of Neurology at Mayo Clinic. He holds additional appointments at the Departments of Bioengineering at the University of Maryland and George Mason University. He founded and currently directs the multi-specialty Center for Vascular Research and the NIH Vascular Imaging Core Facility at the University of Maryland. He has been elected as a Distinguished Fellow of the Society for Vascular Surgery and Distinguished Fellow of the American Venous Forum.