Carotid endarterectomy

# Overview
Carotid endarterectomy (CEA) is a surgical procedure used to correct carotid stenosis (narrowing of the carotid artery lumen by atheroma), used particularly when this causes medical problems, such as transient ischemic attacks (TIAs) or cerebrovascular accidents (CVAs, strokes). Endarterectomy is the removal of material on the inside (end-) of an artery.  Angioplasty and stenting of the carotid artery are undergoing investigation as alternatives to carotid endarterectomy.

# Introduction
Endarterectomy is a surgical procedure for removing plaque within arteries that have caused occlusion. Removal of this plaque in the carotid arteries is called Carotid Endarterectomy (CEA). Patients with blocked carotid arteries can present as symptomatic or asymptomatic. By revascularizing the arteries, blood flow can improve as well as relieve symptoms and future risks.

# History
- 1946- Joao Cid dos Santos performed the first procedure on a superficial femoral artery at the University of Lisbon
- 1951- E. J. Wylie performed the first procedure of endarterectomy on an abdominal aorta. Later that same year surgeons Carrea, Molins, and Murphy repaired a carotid artery occlusion using a bypass procedure.
- 1953- First successful endarterectomy performed by Michael DeBakey at Methodist Hospital in Texas
- 1954- The Lancet journal recorded the first supposed case in medical literature by Felix Eastcott from St Marys Hospital in London. Although later it was realized that he only excised the diseased area and reconnected the health artery.

# Indications
Surgical intervention to relieve atherosclerotic obstruction of the carotid arteries was first performed at St. Marys Hospital, London, in 1954.  Since then, evidence for its effectiveness in different patient groups has accumulated.  In 2003 nearly 140,000 carotid endarterectomies were performed in the USA (Halm).
The aim of CEA is to prevent the adverse sequelae of carotid artery stenosis secondary to atherosclerotic disease, i.e. stroke.  As with any prophylactic operation, careful evaluation of the relative benefits and risks of the procedure is required on an individual patient basis.  Peri-operative combined mortality and major stroke risk are 2  5%.
Carotid stenosis is diagnosed with ultrasound doppler studies of the neck arteries or magnetic resonance arteriography (MRA). The circle of Willis typically provides a collateral blood supply. Symptoms have to affect the other side of the body; if they do not, they may not be caused by the stenosis, and arterectomy it will be of minimal benefit.

### Symptomatic Patients
The North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST) are both large randomized class 1 studies that have helped define current indications for carotid endarterectomy.  The NASCET found that for every six patients treated, one major stroke would be prevented at two years (i.e. a number needed to treat (NNT) of six) for symptomatic patients with a 70  99% stenosis.  Symptomatic patients with less severe carotid occlusion (50  69%) had a smaller benefit, with an NNT of 22 at five years (Barclay).  In addition, co-morbidity adversely affects the outcome; patients with multiple medical problems have higher postoperative mortality and hence benefit less from the procedure.

### Asymptomatic Patients
The European asymptomatic carotid surgery trial (ACST) found that asymptomatic patients may also benefit from the procedure, but only the group with high-grade stenosis (greater than 75%).  For maximum benefit, patients should be operated on soon after a TIA or stroke, preferably within the first month.

### Carotid Revascularization in Patients Undergoing CABG
CEA (with embolic protection) before or concurrent with CABG is reasonable in patients with >80% stenosis who have experienced ipsilateral retinal or hemispheric cerebral ischemic symptoms within 6 months (I, C).
The safety and efficacy of carotid revascularization before or concurrent with myocardial revacularization are not well established (II b, C).

# Contraindications
The procedure is not necessary when:
- There is 100% internal carotid artery obstruction because there is an increased risk of stroke and cerebral damage instead of the surgery reducing the risk.
- The person has a previous complete hemispheric stroke on the ipsilateral and complete cerebrovascular territory side with severe neurologic deficits (NIHSS>15), because there is no brain tissue at risk for further damage.
People deemed unfit for the surgery due to comorbidities.
In a more technical approach, high-risk criteria for CEA 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-day) heart attack
- Severe lung disease or COPD
- Severe renal disease
- High cervical (C2) or intrathoracic lesion
- Prior radical neck surgery or radiation therapy
- Contralateral carotid artery occlusion
- Prior ipsilateral CEA
- Contralateral laryngeal nerve injury
- Tracheostoma

# Equipment
- Stethoscope: Clinical diagnosis can be achieved with the use of a stethoscope. Listening for a carotid bruit, a distinctive sound that occurs when the blood in an artery does not flow smooth as it should.
- Doppler ultrasound: This test shows the flow of blood using ultrasound waves to determine if there is an inconsistency from the normal flow.
- Study imaging: Other tests that can be done are CT scans and MRIs with the use of radioactive dyes for viewing blood flow through the arteries and

# Preprocedure
Before the procedure, imaging tests such as carotid duplex ultrasonography are best used with an accuracy of 80-97% for confirming the severity of stenosis. But if on imaging less than 50% stenosis is observed then further advanced imaging is required to seek out other underlying causes. Once symptoms are correlated with the imaging, patients are prepared for anesthesia. 
The types of anesthesia are general anesthesia and regional anesthesia. Of both types, regional anesthesia is preferred. This is to observe for any intraoperative complications such as cerebral ischemia. On the other hand, general anesthesia is done to reduce the anxiety of the patient and making reentry of the internal carotids smoother. Although the type of anesthesia the patient is put under does not have a significant impact on the outcome of surgery, regional anesthesia reduces the operating time, and the time to recovery.
While being prepared patients are not required to stop any particular medications but instead, they are encouraged to continue taking antiplatelet therapies and blood pressure medications for the prevention of clotting risks and maintaining optimal blood pressures.
After the patient is prepared, they are then placed in a supine position with the head of the patient turned away from the side of surgery. This allows for a wider field to work with. The area is then sterilized, draped, and lighted.

# Procedure

### Conventional CEA
The internal, common and external carotid arteries are clamped, the lumen of the internal carotid artery is opened, and the atheromatous plaque substance removed. The artery is closed, hemostasis achieved, and the overlying layers closed. Many surgeons lay a temporary shunt to ensure blood supply to the brain during the procedure.  The procedure may be performed under general or local anesthesia. The latter allows for direct monitoring of neurological status by intra-operative verbal contact and testing of grip strength.  With general anesthesia, indirect methods of assessing cerebral perfusion must be used, such as electroencephalography (EEG), transcranial doppler analysis and carotid artery stump pressure monitoring.  At present, there is no good evidence to show any major difference in outcome between local and general anesthesia.
Non-invasive procedures have been developed, by threading catheters through the femoral artery, up through the aorta, then inflating a balloon to dilate the carotid artery, with or without a wire-mesh shunt. The safety and effectiveness of these procedures are controversial. In the SAPPHIRE study, Yadav concluded that this procedure, known as carotid stenting, was non-inferior to carotid endarterectomy in total adverse events, and lowered event rates for major stroke, cranial nerve palsy, and myocardial infarction, in patients at high risk for surgery. However, Cambria concluded that the study was not sufficiently powered to detect differences in stroke and death, and final conclusions must await larger trials.

### Eversion CEA

# Postprocedure
After the surgery is complete, the patient is awakened from anesthesia and neurological deficits are ruled out. From there on the patient is sent to the recovery room where they are monitored for 6 hours. During these 6 hours, careful observation is given to neurologic deterioration, blood pressure and bleeding.

# Medications
Common medications taken are antidysrhythmic agents, anticoagulants, and antiplatelets. Antidysrhythmic agents such as 1% Lidocaine Hydrochloride are given to reverse carotid reflex bradycardia. Anticoagulants such as Heparin are given to reduce the thrombotic events. Antiplatelets such as Aspirin and Clopidogrel are given to prevent ischemic strokes. Unless contraindicated, Aspirin is preferred over Clopidogrel.

# Special Situations
- Bilateral carotid stenosis  Unilateral CEA of any vessel in bilateral occlusion leads to increased complications. This led to the NASCET study which further concluded that ipsilateral stenosis and contralateral occlusion augmented the risk for stroke. In all cases, the treatment of symptomatic patients with CEA had better outcomes over medication and is more effective than CAS.
- Prophylactic carotid endarterectomy  Prophylactic CEA is generally considered in patients who have previously undergone coronary artery bypass grafts (CABGs) or major peripheral vascular procedures.

# Complications
- Hypotension
- Hypertension
- Horner syndrome
- Wound hematoma
- Injury to Facial nerve
- Injury to Vagus nerve
- Cranial nerve dysfunction
- Injury to Hypoglossal nerve
- Infection and false aneurysm
- Injury to Glossopharyngeal nerve
- Hyperperfusion and cerebral hemorrhage

# Guideline on the Management of Patients With Extracranial Carotid and Vertebral Artery Disease: Selection of Patients for Carotid Revascularization

# Outcome

# Guideline on the Management of Patients With Extracranial Carotid and Vertebral Artery Disease: Periprocedural Management of Patients Undergoing Carotid Endarterectomy

## Guideline on the Management of Patients With Extracranial Carotid and Vertebral Artery Disease: Management of Patients Experiencing Restenosis After Carotid Endarterectomy or Stenting

# Carotid Endarterectomy (CEA) vs Stenting (CAS)
- The CREST study showed a higher rate of death/MI in patients treated with stenting vs CEA: 6.4% vs 4.7%.
- CEA is preferred in patients who impaired renal function who are at risk of contrast induced nephropathy, tortuous calcified aortas, complex eccentric calcified lesions.
- Stenting may be preferred in patients with high carotid bifurcations where it is hard for surgeons to technically perform the surgery.
- If an elderly patient has a transient ischemic attack and if there is a narrowing in the ipsilateral artery, then carotid endarterectomy should be performed within two weeks of the symptoms.
- CAS is considered over CEA in patients with neck anatomy unfavorable for arterial surgery(II a, B):
Arterial stenosis distal to the second cervical vertebra or proximal (intrathoracic) arterial stenosis
Previous ipsilateral CEA
Contralateral vocal cord paralysis
Open tracheostomy
Radical surgery
Irradiation..
- Arterial stenosis distal to the second cervical vertebra or proximal (intrathoracic) arterial stenosis
- Previous ipsilateral CEA
- Contralateral vocal cord paralysis
- Open tracheostomy
- Radical surgery
- Irradiation..

# Related Chapters
- Carotid artery stenosis