Non-invasive evaluation of segmental pressure drop and resistance in large arteries in humans based on a Poiseuille model of intra-arterial velocity distribution

Study objective – The aim of the study was to evaluate in hypertensive subjects the longitudinal pressure drop and segmental resistance in a large artery in relation to shearing forces of the circulating blood column at the arterial wall. Design – Arterial diameter, blood velocity, and flow were measured in the brachial artery using pulsed Doppler aparatus. Blood viscosity was measured at 96 s−1 with a low shear viscometer. Segmental resistance per unit arterial length was calculated using the basic Poiseuille resistance expression from the ratio between blood viscosity and the fourth power of arterial diameter. Longitudinal pressure drop was deduced as the product between segmental resistance and blood flow. The Poiseuille model of velocity distribution also enabled wall shear rate and stress to be calculated from the ratio between blood velocity and arterial diameter and from the product between shear rate and blood viscosity respectively. Patients – 19 ambulatory male patients with mild to moderate hypertension and 11 normotensive male controls of similar age were studied. Results – Compared to controls, hypertensive patients had higher arterial diameter (p