Cerebrovascular reactivity in carotid artery occlusion: Possible implications for surgical management of selected groups of patients

Objectives - The aim of this study was to use transcranial Doppler ultrasonography to investigate cerebrovascular reactivity to hypercapnia in the middle cerebral arteries of patients with carotid occlusion with different outcomes. Patients and methods - Cerebrovascular reactivity to hypercapnia was calculated with the breath-holding index (BHI). Patients with unilateral carotid occlusion were divided as follows: asymptomatic (20 patients), transient ischemic attack (TIA) (20 patients), minor (20 patients) and major stroke (14 patients). Values of BHI homolateral to the carotid occlusion were compared with those of 25 healthy subjects and 34 stroke patients without significant carotid stenosis. Results - BHI values were comparable in healthy controls, non stenotic stroke patients and asymptomatic occluded patients. BHI values of patients with symptomatic occlusion were significantly lower than those of the above-mentioned groups (P