PREVALENCE OF IMPAIRED CEREBROVASCULAR RESERVE IN PATIENTS WITH SYMPTOMATIC CAROTID-ARTERY DISEASE

Cerebrovascular reserve (CVR) was studied in 104 consecutive patients with symptomatic carotid territory disease and ipsilateral internal ca rotid artery stenosis. Overall, 30 of 104 patients (29 per cent) had i mpaired CVR. The frequency of CVR impairment increased with the severi ty of internal carotid artery stenosis: impairment was present in none of 11 patients with stenosis of less than 50 per cent, four of 24 wit h stenosis of 50-69 per cent, 14 of 41 with stenosis of 70-89 per cent and 12 of 28 with stenosis of 90-99 per cent. Patients presenting wit h a stroke were significantly more likely to have impaired CVR than th ose with transient ischaemic attacks and/or amaurosis fugax (odds rati o 3.7 (95 per cent confidence interval (c.i.) 1.5-9.0)), as were those with a residual neurological deficit (odds ratio 4.3 (95 per cent c.i . 1.6-11.5)) and evidence of infarction from computed tomography (odds ratio 3.8 (95 per cent c.i. 1.6-9.4)).