SYMPTOMATIC CAROTID-ARTERY OCCLUSION - A REAPPRAISAL OF HEMODYNAMIC FACTORS

Background Over the last several years evidence has accumulated that i n addition to embolism, a compromised cerebral blood flow may play an important role in causing transient ischemic attacks and ischemic stro ke in patients with occlusion of the internal carotid artery. This evi dence is found in both clinical features and ancillary investigations, particularly measurements of cerebral blood flow. Summary of Review O n the basis of 20 follow-up studies in patients with transient ischemi c attacks or minor ischemic stroke associated with an occluded carotid artery, the annual risk of stroke was 5.5% (95% confidence interval [ CI], 5.0% to 6.0%), and that of ipsilateral stroke (distinguished in 1 1 of the 20 studies) was 2.1% (95% CI, 1.6% to 2.8%). Patients with a compromised cerebral blood flow as measured by positron emission tomog raphy, single-photon emission CT, transcranial Doppler, or stable xeno n CT (six studies) have an even higher annual risk of stroke (all stro kes: 12.5%; 95% CI, 8.9% to 17.6%; ipsilateral stroke: 9.5%; 95% CI, 6 .4% to 14.0%). Conclusions Because a compromised cerebral blood flow m ay be an important causal factor in patients with symptomatic carotid artery occlusion, medical and surgical options for treatment are revie wed in this light.