Three-section transmission-line arterial model for noninvasive assessment of vascular remodeling in primary hypertension

High central arterial blood pressure can be sustained by the capacity of living arteries to respond to hemodynamic stimuli by changing their structural and/or functional characteristics. These adaptations are considered to occur in a time-dependency, in which different patterns of vascular geometry are identified at all stages. This paper proposes a three-section transmission-line model of the brachial-radial arterial segment and a rational procedure to analyze its transfer function that can be used to interpret the longitudinal remodeling process of medium-sized arteries. The three sections of the model correspond to different arterial segments of the forearm. The model processed pressure signals collected noninvasively from normotensive and hypertensive volunteers at brachial and radial arteries. Aiming to explain possible hypertrophic inward remodeling, geometrical model parameters obtained from normotensive individuals were modified in order to generate high-pressure pulses observed in the hypertensive subjects. The resulting transfer functions for the hypertrophy adaptation exhibit properties related to the pathophysiology of the remodeling process, mainly the reduced amplification of the higher harmonics of the pulse waveform. The results suggest the model can be used to assess noninvasively the hypertension-induced adaptations related to geometrical characteristics of the medium-size arteries.