Interrelation between pulse wave forms in the peripheral arteries registered by methods of impedance rheography and ultrasonic dopplerography

Background and Objectives: Impedance plethysmography and Doppler ultrasound, in most cases, are considered as independent methods for analyzing hemodynamics. This work shows the presence of similarities in the shape of pulse waves recorded by the two indicated methods at rest and during exercise tests. The dynamics of the volume and velocity of blood flow in the radial artery was studied at rest, during an occlusive test and a test with a deep breath. Materials and Methods: The method of impedance rheography was used to determine the dynamics of the blood volume in the artery, and the method of ultrasound dopplerography was used to determine the linear velocity of arterial blood flow. The equation that considers the irregular distribution of erythrocytes velocity in the cross-section of a blood vessel has been obtained for a correct quantitative description of the dynamics of the volumetric blood flow velocity. Results: It has been determined that both the deep breath test and the occlusive test lead to vasodilation of the radial artery. In this case, the test with deep breath causes the appearance of an additional peak in the diastole which agrees in time with the negative (retrograde) diastolic peak of the blood flow velocity. Comparative analysis of the integrated velocity and volume waves demonstrates phase matching and a linear dependence of the shape of these waves at rest which are disrupted during the deep breath test. Conclusions: The proposed equation for calculating volumetric blood flow enables one to study the processes of autoregulation of blood flow in vessels by controlling the balance of changes in blood volume and velocity by the methods of impedance rheography and ultrasound dopplerography and can potentially form the basis for the development of appropriate methods of functional diagnostics.