Pulse Wave 1D Algorithms: 21^st Century Database for Modeling the Hemodynamic Responses to Acute Cardiovascular Stress

We simulated blood flow in the major vasculature of the trunk, limbs, and head to investigate the hemodynamic effects of acute cardiovascular stress (i.e., fear and aerobic exercise). Vessel dimensions were based on modern high-resolution medical imaging data with a focus on active young adult humans. Utilizing a network of reduced-order transmission line elements (0.5 cm or smaller arterial segments), together with peripheral three-element Windkessel models, we solved for instantaneous changes in flow rates and pressures in response to stress-adjusted cardiac output, peripheral resistance, and arterial compliance. Wave propagation was initiated by applying an external force mimicking the myocardial contraction of the left ventricle. We characterized the effects of fear and exercise on systemic arterial wall shear stress (WSS). Compared to the resting state, time-averaged WSS increased by 50% in the brachial arteries (BAs) and by 60% in the femoral arteries (FAs) in response to fear; likewise, WSS increased by 110% in the BAs and by 430% in the FAs during moderate aerobic exercise. Our updated anatomical database is publicly available (DOI: 10.5281/zenodo.4630326) and allows for location-specific assessment of hemodynamics under active physiologic conditions.