North American Symptomatic Carotid Endarterectomy Trial - NASCET


Carotid endarterectomy for stroke and death in symptomatic patients.


Carotid endarterectomy may reduce the risk of stroke and stroke-related death. To identify those patients who would most benefit from carotid endarterectomy. To examine whether carotid endarterectomy maintains or improves the functional status of patients over time.

Study Design

Study Design:

Patients Screened: Not given
Patients Enrolled: 1,212
Mean Follow Up: 30 days
Mean Patient Age: 65.5
Female: 31

Patient Populations:

Patients must have experienced within the past 120 days in the appropriate carotid distribution: one or more transient ischemic attacks, characterized by distinct focal neurologic dysfunction or monocular blindness with clearing of signs and symptoms within 24 hours; one or more minor (nondisabling) completed strokes with persistence of symptoms or signs for more than 24 hours.
Selective carotid angiography must have been performed within 120 days of entry with a minimum of two projections showing both the cervical and intracranial portions of the carotid arteries and their major intracranial branches.
Computerized tomography of the head, duplex sound of the carotid arteries, and chest radiograph.


Not competent to give informed consent because of repetitive language difficulty, intellectual decline, or psychiatric illness.
Without clear and adequate selective angiographic visualization of the carotid arteries or their intracranial branches.
Carotid occlusive disease distal to the body of the second cervical vertebral body that is more significant than the surgically accessible lesion in the more proximal portion of the artery.
Total internal carotid artery occlusion or carotid stenosis of less than 30%.
No symptoms appropriate to the stenotic lesion
>79 years of age.
Organ failure of kidney, liver, heart, or lung or have cancer likely to cause death within five years
Cerebral infarction on either side of sufficient size to deprive the patient of all useful function in the affected territory.
Symptoms caused by nonarteriosclerotic disease.
Cardiac valvular lesion or rhythm disorder of a type likely to be associated with cardioembolic cerebral vascular symptoms.
No occurrence of an ischemic event in the appropriate territory within the previous 120 days.
Previous ipsilateral carotid endarterectomy.

Primary Endpoints:

Fatal or nonfatal stroke ipsilateral to the carotid lesion.

Secondary Endpoints:

Strokes (severity) and all deaths

Drug/Procedures Used:

Carotid endarterectomy and best available medical therapy

Concomitant Medications:

Aspirin, 1300 mg/day (if no side effects)

Principal Findings:

Results are available for patients in the group with the most severe stenoses. Life-table estimates of the cumulative risk of any ipsilateral stroke at two years were 26% of the medical patients and 9% of the surgical patients (P < 0.001).


Because a significant benefit became obvious for patients with a 70 to 99% stenosis, the monitoring committee stopped the trial for these patients. Despite higher perioperative morbidity in the presence of an occluded contralateral artery, the longer-term outlook for patients who had endarterectomy performed on the recently symptomatic, severely stenosed ipsilateral carotid artery was considerably better than for medically treated patients.


1. N Engl J Med 1991;325:445-53. Final results

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Vascular Medicine, Interventions and Imaging, Interventions and Vascular Medicine, Nuclear Imaging

Keywords: Radiography, Thoracic, Stroke, Ischemic Attack, Transient, Tomography, Endarterectomy, Carotid, Blindness, Carotid Arteries, Constriction, Pathologic, Carotid Stenosis

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