Effects of Aging and Hematocrit on Cerebral Blood Flow Velocity in Patients with Unilateral Cerebral Infarctions: A Doppler Ultrasound Evaluation

Abstract

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.

Influence of hemorheological parameters and mean blood pressure on carotid blood flow asymmetry in patients with chronic unilateral cerebral infarctions

“…The cardiac function seems to has a direct influence on the left carotid blood flow, maintaining the showing that these risk factors worsen the carotid blood flow predominantly on the side of the cerebral infarction due to insufficient collateral circulation. Similar results were found in our previous studies using conventional CW [13] and transcranial Doppler sonography [11]. All these findings are in agreement with the hypothesis of Wood and Kee [15], who suggested that the reduction in cerebral blood flow secondary to increased BV associated with HT has an inverse effect on the collateral blood flow in patients with UCI.…”

Transcranial Doppler Pulsatility Indices as a Measure of Diffuse Small‐Vessel Disease

“…Of particular relevance to this study is the fact that prior studies have suggested that small arterial vessels are a significant determinant of vascular resistance. 16,17 Previous investigators have demonstrated an elevation in PIs with increasing age 18,19 and hypertension 20 and with the presence of vascular dementia. 21 In our study, both age and hypertension were strongly correlated with increasing PI on univariate analysis; however, in multivariate analysis, only age remained an independent predictor of higher PI.…”

The value of transcranial Doppler derived pulsatility index for diagnosing cerebral small-vessel disease

“…Recent studies showed that PI increases in hyperlipidemia, hypertension,[ 14 ] diabetes,[ 15 ] increasing age,[ 16 ] and vascular dementia. [ 17 ] Some studies showed that another indexes in TCD not PI increase due to SVD.…”