Vascular wall shear index in progressive carotid artery atherosclerosis

Objective. To assess the index of vascular wall shear in carotid artery atherosclerosis. Material and methods. During the study, 32 healthy male and female volunteers (mean age 35±1.2 years) as well as 47 patients with carotid artery pathology (mean age 66±2.7 years) were examined. The investigation was carried out on Mindray Resona 7 ultrasound machine (China), equipped with linear sensor (3—11 MHz) with updated Vflow software. Systolic (Vs) and diastolic (Vd) blood flow velocities were recorded before and after stenosis. The wall shear stress (WSS) and the oscillation index (OSI) were evaluated using the built-in program on vector analysis. These indices were analyzed in the internal carotid artery before and after the plaque. The correlation coefficient between wall shear stress and blood flow velocity was calculated. Results. In the case of atherosclerotic lesions of the internal carotid artery, the index of oscillation and stress was different from normal (p<0.001). The degree of damage to the internal carotid artery was estimated by blood flow velocity, wall stress and oscillation index. The mean artery wall stress was more than 10 times lower in patients with atherosclerosis (0.05±0.01), and the oscillation index (0.23±0.1) — 7 times higher. Conclusion. At the level of the internal carotid artery stenosis, the wall shear stress was significantly higher in the direction of blood flow. Movement velocities at medium and high deformation values are one of the indicators for identification of the vessel wall stenosis areas. Recording of wall shear stress by means of vector flow mapping in patients with cerebrovascular diseases is a new promising direction for assessing the atherosclerotic lesion development.