Table 1 Inclusion/Exclusion Criteria for Carotid Endarterectomy Trials

NASCET [9]

Inclusion

Symptoms of focal cerebral ischemia ipsilateral to a stenosis of <70% (moderate group) or ≥70% (severe group) within 180 days, as shown on angiography

Symptoms lasting <24 hours or producing nondisabling stroke (Rankin score <3)

Exclusion

Age >80 years (initial phase of moderate and severe stenosis; continuing study of moderate stenosis included these patients)

Lack of angiographic visualization of symptomatic artery

Lack of informed consent

Intracranial stenosis more severe than the cervical stenosis

Other disease limiting life expectancy to <5 years

Cerebral infarction limiting useful function in the affected arterial territory

Nonatherosclerotic carotid disease

Cardiac lesions likely to cause cardioembolism

History of ipsilateral carotid endarterectomy

ACAS [8]

Inclusion

Age 40–79 years

Compatible history and findings on physical and neurologic examination

Acceptable laboratory and electrocardiogram results

Arteriography within the previous 60 days indicating stenosis of at least 60% reduction in diameter (if arteriography performed 61–364 days before randomization, repeat Doppler showing artery still patent) or Doppler examination within 60 days showing a frequency or velocity greater than the instrument-specific cut point with 95% positive predictive value or Doppler examination showing a frequency or velocity greater than the instrument-specific 90% positive predictive value cut point confirmed by ocular pneumoplethysmographic examination within the previous 60 days

Exclusion

Cerebrovascular event in the distribution of the affected carotid artery or the vertebrobasilar system

Symptoms referable to the contralateral cerebral hemisphere within the previous 45 days

Contraindication to aspirin therapy

Any disorder that could seriously complicate surgery

Any condition that could prevent continuing participation or likely to produce death or disability within 5 years

Lack of informed consent