The CHAT classification of stroke.

Current terminology for clinical episodes relating to stroke is inconsistent and unclear, does not permit inclusion of data regarding the location and magnitude of extracranial and intracerebral arterial disease, does not coincide with existing classifications in Europe, and characterizes a hemispheric entity only, as opposed to a global description including prior symptoms in both hemispheres. A new classification system (CHAT) has been designed to deal with these problems, including the current clinical presentation, historical clinical episodes, the site and pathologic type of arterial disease, and information regarding abnormalities of the brain. Using this system, a retrospective review of 480 consecutive carotid endarterectomies is presented, demonstrating the advantages of the CHAT classification. Data include a significant difference in the probability of survival after carotid endarterectomy for asymptomatic stenosis in patients with prior symptoms on the opposite side, as well as a significant difference in the probability of stroke-free survival between patients with amaurosis fugax and those with prior carotid cortical symptoms (TIAs) as the presenting clinical condition. The CHAT classification is suggested as a significant advance in the reporting of all surgical cerebrovascular disease experience, and has particular implications for the current randomized trials between medical and surgical therapy for carotid artery disease.