Reduced order modeling of the circulatory system hemodynamics for 0D-3D coupled simulations

Lower dimensional lumped parameter networks (LPN) coupled to 3D models provides a relatively accurate method for capturing global hemodynamics of the circulatory system at an affordable cost. In this method, the major vessels are fully solved in a 3D model of patient anatomy whereas the rest of the circulatory system is often modeled with a 0D LPN. Provided a set of clinical measurements, tuning components in the LPN poses a major challenge in this approach as it requires adjusting model parameters (LPN 0D components) to minimize the difference between model output and clinical measurements. This optimization procedure can be costly as it requires simulating the 3D domain at each iteration. In this study, we offer an alternative approach, where a simplified 0D circuit model replaces the 3D model, thereby reducing the cost of the tuning process at each iteration to simulating an inexpensive 0D-0D coupled model. To construct this simplified model, we developed a separate optimization algorithm that is tailored to this problem. We demonstrate the reasonable accuracy and computational cost efficiency of our approach by comparing it to the standard 3D/0D procedure.