No relationship between cerebral blood flow velocity and cerebrovascular reserve capacity and contemporaneously measured glucose and insulin concentrations in diabetes mellitus

Blood glucose and insulin concentrations have been reported to influence ce rebral hemodynamics. We studied the relationship between actual blood gluco se and insulin concentrations and resting cerebral blood flow velocity in t he middle cerebral artery and cerebrovascular reserve capacity after acetaz olamide stimulation. Thirty-six insulin-dependent diabetic patients in a st ate of good glycemic control were studied. Blood samples were taken for det ermination of glucose and insulin concentrations. Subsequently we measured resting cerebral blood flow velocities in supine position using transcrania l Doppler, administered 1 g acetazolamide intravenously, and repeated the m easurements after 5, 10, 15 and 20 minutes. Cerebrovascular reserve was cal culated as the maximal percent increase after acetazolamide stimulation. Mu ltiple regression was used for statistical analysis. Blood glucose levels were not correlated with resting blood flow velocity ( R = 0.21, p = 0.22) nor cerebrovascular reserve capacity (R = 0.17, p = 0.3 2). Similarly, no correlation was found between insulin concentrations, res ting cerebral blood flow velocity (R = 0.24, p = 0.22) and cerebrovascular reserve (R = 0.26, p = 0.24). Studying patients with long-term (> 10 years) and short-term (less than or equal to 10 years) disease duration yielded t he same lack of correlation. We conclude that there is no significant correlation between contemporaneou sly measured glucose and insulin concentrations and either cerebral blood f low velocity or cerebrovascular reserve capacity in the middle cerebral art ery in type 1 diabetic patients with good control.