Three Dimensional Fluid Structure Interaction Modeling of Hemodynamics with Continuous Postures

A sudden postural change may produce symptoms or even syncope mainly due to orthostatic hypotension. To date, most hemodynamic studies in postural change focus on the response of static and definite postures. To quantify cardiovascular hemodynamics characteristics during continuous posture, we developed a three-dimensional fluid-structure interaction mathematical model of hemodynamics with continuous posture. In this model, the rotating inertial forces were introduced. By the finite element method, the distribution of blood flow pressure (DBFP) in the inner carotid artery in ±90° postures was numerically simulated with rotation and gravity concerned or not. The simulations are as follows: (1) whether gravity was considered or not, the DBFP varied from two-dimensional axisymmetrical distribution without rotation to threedimensional asymmetrical one with rotation considered, and extreme pressures occurred in the same positions in the two cases. (2) The effect intensity of rotation is larger than the effect intensity of gravity. So, unlike gravity, rotation affected the DBFP. This indicates that hemodynamic characteristics in certain position during dynamic change of posture obviously differ from that in static and definite posture. This study may provide a novel way to characterize hemodynamics during continuous posture, and consequently help to evaluate the syncope patients, astronauts or pilots and athletes with unexplained syncope more accurately. Keywords— Blood flow pressure, Continuous posture, Gravity, Hemodynamics, Mathematical Model, Rotation, Syncope.