Cerebrovascular reactivity and reserve capacity in type II diabetes mellitus.
ABSTRACT The aim of the study was to test the hypothesis that cerebrovascular reserve capacity and cerebrovascular reactivity are impaired in patients suffering from non insulin-dependent diabetes mellitus. We also intended to investigate factors which may influence resting cerebral blood flow velocity and cerebrovascular reserve capacity. A total of 28 patients suffering from type II diabetes mellitus and 20 healthy control subjects were studied. Based on diabetes duration patients were divided into two groups: subjects with > 10 years and those with < or = 10 years disease duration. Middle cerebral artery mean blood flow velocities were measured at rest and after intravenous administration of 1g acetazolamide. Cerebrovascular reactivity and reserve capacity were calculated. Blood glucose, insulin, glycosylated 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 subgroups and controls. Correlations between laboratory parameters and cerebrovascular reserve were investigated by linear regression analysis. Resting cerebral blood flow velocity was similar in controls and in the two diabetic subgroups. Cerebrovascular reactivity was elevated for a shorter time in patients with > 10 years disease duration than in controls and short-term diabetic patients. Cerebrovascular reserve capacity was lower in the long-term diabetes group (means +/- SD: 39.6 +/- 20.7%) than in patients with < or = 10 years disease duration (63.3 +/- 17.4%, p < 0.02 after Bonferroni 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 cerebrovascular reserve capacity. The vasodilatory ability of cerebral arterioles is diminished in long-standing type II diabetes mellitus.
Article: Cerebrovascular reserve capacity is preserved in a population-based sample of patients with type 2 diabetes mellitus.[show abstract] [hide abstract]
ABSTRACT: Type 2 diabetes mellitus (DM2) is associated with an increased risk of stroke. DM2 is also associated with cognitive impairments. Vascular dysfunction, such as impaired cerebrovascular reserve capacity (CVR), may be a determinant of these changes, but previous studies on CVR in DM2 have provided variable results in selected populations of patients. We aimed to examine CVR in a population-based sample of DM2 patients. The CO(2) reactivity of the middle cerebral artery was examined using transcranial Doppler ultrasonography in 81 DM2 patients and 38 controls. In DM2 patients CVR was correlated with diabetic parameters, vascular risk factors and cognitive functioning. CVR was similar in patients and controls (51 vs. 49%). Within the DM2 group, there was no statistically significant relationship between CVR and DM duration, HbA(1c), albuminuria, blood pressure, intima-media thickness and cognition. CVR tended to be lower in diabetic patients with retinopathy [46 vs. 55%, mean difference: -7.9 (confidence interval -18.0, 2.2)]. We conclude that CVR is not impaired in unselected patients with DM2 and probably does not, therefore, play a major role in the aetiology of cognitive impairment.Cerebrovascular Diseases 02/2006; 22(1):46-50. · 2.72 Impact Factor