1. A computer-implemented method for determining a hemodynamic pressure quantity, the method comprising: acquiring angiography data from a patient at a first physiological state of the patient, the first physiological state comprising a state of hyperemia, a state of rest, or a state of exercise, the angiography data comprising x-ray angiography data, magnetic resonance angiography data, and/or computed tomographic angiography data; determining, by a processor, a first flow in a blood vessel of the patient based on the angiography data, wherein the first flow corresponds to the first physiological state of the patient; determining, by the processor, a second flow in a blood vessel based on scaling the first flow by a numerical factor from the first physiological state to a second physiological state, the second physiological state comprising a state of hyperemia, a state of rest, or a state of exercise, wherein the second flow corresponds to the second physiological state of the patient that is different from the first physiological state of the patient; determining, by the processor, the hemodynamic pressure quantity based on the second flow; and reporting the hemodynamic pressure quantity.