1. A system for modifying a three-dimensional model based on one or more cardiovascular treatment options for a patient, the system comprising: at least one computer system configured for: creating a reduced order model representing at least a portion of the patient's heart or vasculature based on patient-specific data regarding a geometry of the patient's heart or vasculature; determining a treatment type for a condition in the patient's heart or vasculature; determining a vessel characteristic of a vessel in the portion of the patient's heart or vasculature; obtaining a stored reduced order model parameter of a stent or a bypass graft based on the determined treatment type and the determined vessel characteristic; modifying the reduced order model of the portion of the patient's heart or vasculature to include the obtained reduced order model parameter of the stent or bypass graft; and determining a blood flow rate or pressure within the portion of the patient's heart or vasculature based on the modified reduced order model.