Common carotid artery hemodynamic factors in patients with cerebral infarctions.

The aim of the study was to investigate the changes of the common carotid local hemodynamic factors like wall shear stress and tensile forces in 16 patients with chronic unilateral cerebral infarctions (CUCI), 58 patients with risk factors (RF) for cerebrovascular disease (CVD) and 25 healthy control subjects. The blood flow velocities (BFV), the internal diameters (D) and the vessel wall intima-media thickness (IMT) in the common carotid arteries (CCA) were recorded with color duplex sonography. Systolic (SBP) and diastolic (DBP) blood pressure were measured and mean blood pressure (MBP) was calculated by the formula of Wiggers. Whole blood viscosity (WBV) at the shear rate of 94.5 s-1 was measured on the day of the Doppler ultrasound examination with a rotational viscometer Contraves Low Shear 30. Wall shear stress (WSS), the circumferential wall tension (T) and the tensile stress tau were calculated. The main RF in the patients' groups were hypertension and hyperlipidemia. The SBP, WBV and IMT were significantly increased in the patients with UCI and RF for CVD in comparison to controls. Lower systolic WSS and tau and higher T were established in the patients with UCI. The IMT correlated with WSS and tau. The study confirms the complex influence of the changes in WBV and blood pressure for the development of carotid atherosclerosis.