[Cerebrovascular reactivity in insulin dependent diabetes mellitus studied by an acetazolamide test]

The aim of this study was to investigate, whether the cerebrovascular reactivity (CR) was altered in diabetes mellitus and to evaluate the influence of diabetes's duration on cerebrovascular reactivity. Transcranial Doppler-Acetazolamide tests were performed on 20 insulin-dependent diabetics and in 19 controls. Patients were divided into two groups, each group consisted of 10 patients: diabetics with > 10 years disease duration and with < 10 years diseases duration. Middle cerebral artery mean velocities were measured at rest and after i.v. administration of Ig Acetazolamide (AZ). There were no differences in the absolute velocities between controls and diabetics. The percentual increase of the mean velocity after AZ was slower and less intensive in longterm diabetics (means +/- SE: 5 min: 19.4 +/- 2.8%, 10 min: 28 +/- 3.6%, 15 min: 25.7 +/- 3.8%, 20 min: 23.9 +/- 4.3%), than that in controls (5 min: 32.3 +/- 4.3% -p < 0.05-, 10 min: 45.1 +/- 4.9% -p < 0.05-, 15 min: 47.5 +/- 4.3% -p < 0.01-, 20 min: 46.5 +/- 4.7% -p < 0.01) as well as in diabetics with < 10 years disease duration (5 min.: 39.5 +/- 7% -p < 0.05-, 10 min.: 49.2 +/- 6.5% -p < 0.05-, 15 min.: 53.9 +/- 8.6% -p < 0.01-, 20 min: 32.9 +/- 5.9% -n.s.). The cerebrovascular reactivity is impaired in diabetics after long duration of the disease. The altered cerebrovascular reactivity might be caused by angiopathy of the cerebral arterioles.