Cervical arteriosclerosis--diagnostic advances in need of a clinical answer.

OVER THE PAST SEVEN decades, a relationship between thrombo-embolic stroke and arteriosclerotic changes of the carotid and vertebral arteries has been established. 1_n While the role of extracranial arterio sclerotic disease in the etiology of stroke is agreed to be important, its exact contribution remains unde fined. Largely responsible for this uncertainty are: the frequent coexistence of similar arteriosclerotic changes in both the cervical and intracranial vascula ture; the presence of morphologically identical forms of atherosclerotic disease in comparable locations in both symptomatic and asymptomatic patients; the fact that clinical manifestations of thrombo-embolic stroke are, for the most part, related more to physiological changes than to disturbed anatomy; and heretofore the need to use invasive procedures, carrying un acceptable risks, to document the lesions of arteriosclerosis."' ' 2 Once it has occurred, the course of an ischemic stroke remains to an unacceptable degree refactory to therapy, leading either to persistent neurological dys function or death in a majority of patients. A favorable therapeutic approach therefore must be prophylactic, a restriction requiring recognition of the population at risk before they have suffered a stroke. Most commonly, ischemia or infarction of the brain does not represent a disease per se but rather is a nonspecific incidental manifestation of steadily pro gressive arteriosclerosis affecting arteries throughout the body. 13 In this regard, a cohort from the general population who are at increased risk for the occurrence of an ischemic cerebrovascular accident can be identi fied. Hypertension, diabetes mellitus, cardiac dys function as measured by either clinical, radiographic or electrical parameters, smoking, obesity and stress all have been implicated as factors which serve as markers for this population. Through the use of statisti cal methods, a stroke risk profile can be developed based on these factors. Such a profile allows recogni tion of that segment of the still asymptomatic group in which half of the thrombo-embolic strokes will occur. Persons in this population have a 40 to 47% chance of suffering such a calamity within eight years. 12 Others at risk may be recognized because of historical ac counts of intermittent transient ischemic attacks or as a result of findings on physical examination such as ca rotid bruits or ophthalmoscopic abnormalities.'°-' 4 l5-l6 Over the last decade, simultaneously with the accu mulation of epidemiological data, extensive efforts have been directed towards development of safe tech niques for assessment of the extracranial vasculature. In this …