COMPROMISED CEREBRAL BLOOD-FLOW REACTIVITY IS A PREDICTOR OF STROKE IN PATIENTS WITH SYMPTOMATIC CAROTID-ARTERY OCCLUSIVE DISEASE

Purpose: The purpose of this study was to determine whether the hemody namic consequences of extracranial carotid disease correlate with the risk of subsequent cerebral infarction. Methods: In 95 patients with s ymptoms who had greater than or equal to 70% stenosis (31 patients) or who had occlusion (64 patients) of the ipsilateral carotid artery, ce rebral blood how was measured by the stable xenon/computed tomography technique both at baseline and after vasodilatory challenge with intra venous acetazolamide. Patients were stratified into group 1, 43 patien ts with no more than a 5% decrease in flow in any vascular territory, and group 2, 52 patients with greater than a 5% decrease in one or mor e vascular territories after an acetazolamide challenge. Results: In g roup 2, 15 (28.9%) of 52 patients had a new stroke, but only one (2.3% ) of 43 patients in group 1 did (p = 0.0005). Of patients with total c arotid occlusion 10 (26%) of 38 in group 2 and none (0%) of 26 in grou p 1 had a new stroke (p = 0.003). Of patients with greater than or equ al to 70% stenosis, five (36%) of 14 in group 2 and only one (6%) of 1 7 in group 1 had a stroke (p = 0.067). Conclusion: The loss of cerebra l reactivity in patients with symptoms who had greater than or equal t o 70% carotid stenosis or occlusion is an important predictor of impen ding cerebral infarction.