Table 1 Inclusion/Exclusion Criteria for Carotid Endarterectomy Trials

        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)
        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]
        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
        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