The contribution of upper and lower body arterial vessels to the aortic root reflections: A one-dimensional computational study

BACKGROUND AND OBJECTIVES: Reflections measured at the aortic root are of physiological and clinical interest and thought to be composed of the superimposed reflections arriving from the upper and lower parts of the circulatory system. However, the specific contribution of each region to the overall reflection measurement has not been thoroughly examined. This study aims to elucidate the relative contribution of reflected waves arising from the upper and lower human body vasculature to those observed at the aortic root. METHODS: We utilised a one-dimensional (1D) computational model of wave propagation to study reflections in an arterial model that included 37 largest arteries. A narrow Gaussian-shaped pulse was introduced to the arterial model from five distal locations: carotid, brachial, radial, renal, and anterior tibial. The propagation of each pulse towards the ascending aorta was computationally tracked. We calculated the reflected pressure and wave intensity at the ascending aorta in each case. The results are presented as a ratio of the initial pulse. RESULTS: The findings of this study indicates that pressure pulses originated at the lower body can hardly be observed, while those originated from the upper body account for the largest portion of reflected waves seen at the ascending aorta. CONCLUSIONS: Our study validates the findings of earlier studies, which demonstrated that human arterial bifurcations have a significantly lower reflection coefficient in the forward direction as compared to the backward direction. The results of this study underscore the need for further in-vivo investigations to provide a deeper understanding of the nature and characteristics of reflections observed in the ascending aorta, which can inform the development of effective strategies for the management of arterial diseases.