A system and method of modeling flow of a vasculature in near real-time, is described. A vessel segment of the vasculature is modeled by a reduced order model, and a remainder of the vasculature is modeled by a 0D model. The reduced order model is generated using boundary conditions generated by a 0D model of the entire vasculature. Moreover, the reduced order model of the vessel segment and the 0D model of the remainder of the vasculature can be coupled to simulate flow that can be compared to actual flow measurements to personalize the 0D model of the remainder of the vasculature for a patient. Accordingly, a physician can update parameters of the personalized vascular system model to predict the effects of treatment protocols, including exercise or therapeutic substances, on the patient. Other embodiments are also described and claimed.