Age and sex dependence of hemodynamic parameters of human internal carotid arteries

The study of the ultrasound diameter, linear velocity, and resistance of the internal carotid arteries in 647 subjects of both sexes aged from 1 to 74 years has been performed. Additionally, shear stress and the Reynolds number have been calculated. During the period from early childhood to adolescence and from the first mature to younger elderly ages, there is an increase in the diameter of the internal carotid arteries. Phases of an increase in the vascular resistance by the first period of childhood, adolescence, and younger elderly age are observed. The space flow velocity has relatively stable parameters till youth, and then it declines by younger elderly age. The average linear velocity, shear stress, and the Reynolds number progressively diminish twice by younger elderly age. Laminar blood flow with local twists in the early stages of postnatal ontogenesis is characteristic of the internal carotid arteries. The diameter of the internal carotid arteries, vascular resistance index, and blood flow velocity are higher in men than in women during most age periods. Shear stress in both internal carotid arteries during all the age periods studied is symmetrical and has no sex differences.