Effects of aging and hematocrit on cerebral blood flow velocity in patients with unilateral cerebral infarctions: a Doppler ultrasound evaluation.

By means of conventional continuous-wave (CW) (4 MHz) and transcranial pulsed (2 MHz) Doppler sonography 50 patients (34 men and 16 women, mean age 58.6 +/- 7.6 years) who survived unilateral cerebral infarctions (UCI) in the middle cerebral artery (MCA) territory were investigated. The control group consisted of 30 presumed healthy age-matched persons. The main quantitative sonographic parameters of the major arteries of the head and the basal cerebral arteries were evaluated. On the day of the neurosonographic investigations, hematocrit (Hct) was determined. Low-degree stenoses of the internal carotid arteries were found in 26 (52%) of the patients. Increased intracranial vessels' resistance in the MCA on the infarction side was usually obtained. Decreasing of Doppler shift frequency with advancing age and increasing of Hct was established in the controls. In patients with UCI the effects of aging and Hct on the sonographic parameters of the collateral arteries were more pronounced. Obviously, in patients with UCI, the alterations of the sonographic parameters are caused by parallel influence of vessels' disease, age-defined changes of vessels' walls, and viscosity variations.