Cerebrovascular reactivity and reserve capacity in type II diabetes mellitus

The aim of the study was to test the hypothesis that cerebrovascular reserv e capacity and cerebrovascular reactivity are impaired in patients sufferin g from non insulin-dependent diabetes mellitus. We also intended to investi gate factors which may influence resting cerebral blood flow velocity and c erebrovascular reserve capacity. A total of 28 patients suffering from type II diabetes mellitus and 20 healthy control subjects were studied. Based o n diabetes duration patients were divided into two groups: subjects with > 10 years and those with less than or equal to 10 years disease duration. Mi ddle cerebral artery mean blood flow velocities were measured at rest and a fter intravenous administration of 1g acetazolamide. Cerebrovascular reacti vity and reserve capacity were calculated. Blood glucose, insulin, glycosyl ated hemoglobin, hemostatic factors (fibrinogen, alpha-2 macroglobulin and von Willebrand factor antigen) were determined. Cerebrovascular reactivity and reserve capacity values were compared between the two diabetic subgroup s and controls. Correlations between laboratory parameters and cerebrovascu lar reserve were investigated by linear regression analysis. Resting cerebr al blood flow velocity was similar in controls and in the two diabetic subg roups. Cerebrovascular reactivity was elevated for a shorter time in patien ts with > 10 years disease duration than in controls and shortterm diabetic patients. Cerebrovascular reserve capacity was lower in the long-term diab etes group (means +/- SD: 39.6 +/- 20.7%) than in patients with less than o r equal to 10 years disease duration (63.3 +/- 17.4%, p < 0.02 after Bonfer roni correction). Cerebrovascular reserve capacity was inversely related to the duration of the disease (R = 0.53, p < 0.003). None of the determined laboratory factors had any relation with resting cerebral blood flow and ce rebrovascular reserve capacity. The vasodilatory ability of cerebral arteri oles is diminished in long-standing type II diabetes mellitus. (Journal of Diabetes and Its Complications 13;4:191-199, 1999.) (C) 1999 Elsevier Scien ce Inc.