CEREBROVASCULAR REACTIVITY BY TRANSCRANIAL DOPPLER ULTRASONOGRAPHY IN INSULIN-DEPENDENT DIABETIC-PATIENTS

Cerebrovascular reserve capacity (CVRC) was investigated in 13 insulin-dependent diabetic (IDDM) patients with clinical microangiopathy and in 12 healthy subjects. CVRC was assessed by transcranial Doppler (TCD) ultrasonography continuously recording mean blood flow velocity (FV(m)) of the middle cerebral artery in the resting condition and for 2 h after an i.v. injection of 1 g acetazolamide. The increase in FV(m) was observed a few minutes after the injection of acetazolamide with the highest value being reached after 10 min in both IDDM patients and controls. Each single curve was significantly increased in controls and in the diabetic group (p < 0.001 by one-way Anova analysis and the Scheffe test). When comparing FV(m) in IDDM patients and controls. the values of the IDDM patients were significantly lower at all times (p < 0.05). An age-dependent decline of FV(m) was observed in IDDM patients at rest (p = 0.016), but not in healthy controls (NS). The absolute increase in mean blood flow velocity after 10 min was 16.7 +/- 8.5 cm/s (mean +/- SD) in IDDM patients and 24.1 +/- 9.3 cm/s in controls (p < 0.05), while 3 out of 13 IDDM patients had a CVRC below 1 SD of the control group. The acetazolamide test and TCD ultrasonography seem to be useful methods for assessing CVRC in IDDM patients,