Assessing arterial wave transmission from micro- to hypergravity: A multiscale cardiovascular modeling approach

The human cardiovascular system is adapted to terrestrial gravity, yet transitions toward microgravity and hypergravity induce marked blood redistribution and hemodynamic changes. Despite their clinical relevance, arterial pressure and flow wave dynamics under altered gravity remain poorly characterized, owing to scarce direct measurements beyond ground-based studies. Here, a validated fluid dynamics-based multiscale cardiovascular model was used to investigate arterial wave transmission and reflection in standing posture across the 0g–3g range. Pulse wave velocity maintained its proximal-to-distal increase at fixed g, while showing opposite gravity-dependent trends across the orthostatic indifference point (decreasing above and increasing below), mainly driven by wall stiffness changes. Backward waves were attenuated more than forward waves, and reflection indices decreased throughout the network, including the lower limbs. Bifurcation- and tapering-related effects were only weakly gravity-sensitive, whereas distal peripheral resistances emerged as the dominant mechanism modulating wave amplitudes. Wave trapping remained preserved along the aortic tract, limiting central reflected wave load. Present findings indicate a gravity-resilient wave-filtering behavior of the arterial network and provide a mechanistic framework for studying cardiovascular adaptation to extreme environments.