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Carotid endarterectomy is a
surgical Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...
procedure used to reduce the risk of
stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop funct ...
from
carotid artery stenosis Carotid artery stenosis is a narrowing or constriction of any part of the carotid arteries, usually caused by atherosclerosis. Signs and symptoms The common carotid artery is the large artery whose pulse can be felt on both sides of the neck unde ...
(narrowing the
internal carotid artery The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these ...
). 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 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 i ...
, which can also reduce the risk of stroke for some patients.


Medical uses

Carotid endarterectomy is used to reduce the risk of
stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop funct ...
s caused by
carotid artery stenosis Carotid artery stenosis is a narrowing or constriction of any part of the carotid arteries, usually caused by atherosclerosis. Signs and symptoms The common carotid artery is the large artery whose pulse can be felt on both sides of the neck unde ...
over time. Carotid stenosis can either have symptoms (i.e., be symptomatic), or be found by a doctor in the absence symptoms (asymptomatic) - and the risk-reduction from endarterectomy is greater for symptomatic than asymptomatic patients. Carotid endartectomy 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. Carotid endarterectomy does not treat symptoms of prior strokes. It is controversial if carotid endarterectomy can improve cognitive function in some patients.


Symptomatic

Symptomatic people have had either a
stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop funct ...
or
transient ischemic attack 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. TIA causes the same symptoms associated with strokes, such as weakness or numbness on one side of ...
. 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 The number needed to treat (NNT) or number needed to treat for an additional beneficial outcome (NNTB) is an epidemiological measure used in communicating the effectiveness of a health-care intervention, typically a treatment with medication. The ...
of six). Unlike asymptomatic patients, symptomatic people with mild carotid stenosis (50–69%) still benefit from endarterectomy, albeit to a lesser degree, with a number needed to treat of 22 at five years. In addition, co-morbidity adversely affects the outcome: people with multiple medical problems have a higher post-operative
mortality rate Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular population, scaled to the size of that population, per unit of time. Mortality rate is typically expressed in units of de ...
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.


Asymptomatic

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, carotid endarterectomy plus treatment with a
statin Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs. L ...
medicine and anti-platelet therapy does reduces stroke risk further than medication alone in the five years following surgery for asymptomatic patients with severe carotid stenosis (80-99%).


Complications

The most feared complication of carotid endarterectomy is
stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop funct ...
. Risks of stroke at the time of surgery are higher for symptomatic (3–5%) than asymptomatic patients (1–3%). Bleeding, infection, and
cranial nerve Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and f ...
injury are also risks at the time of surgery. Following surgery, a rare early complication is
cerebral hyperperfusion syndrome Cerebral hyperperfusion syndrome, also known as reperfusion syndrome, is a dysregulated state of cerebral blood flow following the restoration of arterial blood flow to the brain, usually following treatment of carotid artery stenosis. Risk factor ...
, 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.


Reasons to avoid

The procedure should be avoided when: *There is complete internal carotid artery occlusion *The person has a previous complete hemispheric stroke on the
ipsilateral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...
and complete cerebrovascular territory side severe neurologic deficits (NIHSS>15), because there is no brain tissue at risk for further stroke damage. *People deemed unfit for the operation by the surgeon or anesthesiologist due to comorbidities. High risk criteria for carotid endarterectomy include the following: *Age ≥80 years *Class III/IV congestive heart failure *Class III/IV angina pectoris *Left main or multi vessel coronary artery disease *Need for open heart surgery within 30 days *Left ventricular ejection fraction of ≤30% *Recent (≤30 days) heart attack *Severe lung disease or chronic obstructive pulmonary disease *Severe renal disease *High cervical (C2) or intrathoracic lesion *Prior radical neck surgery or radiation therapy *Contralateral carotid artery occlusion *Prior ipsilateral carotic endarterectomy. *Contralateral laryngeal nerve injury *Tracheostoma Carotid artery stenting is an alternative to carotid endarterectomy in cases where endarterectomy is considered too risky.


Procedure

An incision is made on the midline side of the
sternocleidomastoid muscle The sternocleidomastoid muscle is one of the largest and most superficial cervical muscles. The primary actions of the muscle are rotation of the head to the opposite side and flexion of the neck. The sternocleidomastoid is innervated by the access ...
. The incision is between 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 and a patch to increase the size of the lumen.
Hemostasis In biology, hemostasis or haemostasis is a process to prevent and stop bleeding, meaning to keep blood within a damaged blood vessel (the opposite of hemostasis is hemorrhage). It is the first stage of wound healing. This involves coagulation, ...
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 A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in ...
during the procedure. The procedure may be performed under general or local
anaesthesia Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), a ...
. The latter allows for direct monitoring of neurological status by intra-operative verbal contact and testing of grip strength. With general anaesthesia, indirect methods of assessing cerebral perfusion must be used.
Electroencephalography Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex ...
(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 no good evidence to show any major difference in outcome between local and general anaesthesia, nor between methods of determining the need for a shunt.


History

The endarterectomy procedure was developed and first done by the Portuguese surgeon Joao Cid dos Santos in 1946, when he operated an occluded superficial femoral artery, at the
University of Lisbon The University of Lisbon (ULisboa; pt, Universidade de Lisboa, ) is a public research university in Lisbon, and the largest university in Portugal. It was founded in 2013, from the merger of two previous public universities located in Lisbon, th ...
. In 1951 an Argentinian surgeon repaired a carotid artery occlusion using a bypass procedure. The first endarterectomy was successfully performed by
Michael DeBakey Michael Ellis DeBakey (September 7, 1908 – July 11, 2008) was a Lebanese-American general and cardiovascular surgeon, scientist and medical educator who became Chairman of the Department of Surgery, President, and Chancellor of Baylor Colleg ...
around 1953, at the Methodist Hospital in Houston, TX, although the technique was not reported in the medical literature until 1975. The first case to be recorded in the medical literature was in The Lancet in 1954; the surgeon was Felix Eastcott, a consultant surgeon and deputy director of the surgical unit at
St Mary's Hospital, London St Mary's Hospital is an NHS hospital in Paddington, in the City of Westminster, London, founded in 1845. Since the UK's first academic health science centre was created in 2008, it has been operated by Imperial College Healthcare NHS Trust, w ...
, UK. 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. 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.


References

{{DEFAULTSORT:Carotid Endarterectomy Vascular surgery Neurosurgery Stroke