Vascular resistance estimation in renal hemodynamics using a time-varying Windkessel model

In studies of the dynamics of renal vascular response to blood pressure variations, measurements of pressure and flow rate are typically utilized to characterize a dynamic response with pressure as input and flow as output. However, the primary regulatory effect is the adjustment of vascular resistance, so that a record of a resistance time series would better serve as the regulated output. Toward this goal, a technique is developed for estimating the parameters of a three-element, time-varying Windkessel model of the renal vasculature that enables resistance estimation. The method is described, analyzed, and applied to renal pressure/flow data from rats.