Figure 1

Schematic representation of the lumped-parameter model and input data used to calibrate it. On the top, IVUS registration was illustrated in the yellow rectangle: a slice was selected to extract the geometrical measurements related to the more proximal tract (OSTIUM) of a right CA. In the green rectangle, the points selected along the centerline of the 3D model of the aortic root were shown; they were used to measure aortic geometrical parameters. The 3D model was reconstructed through the segmentation of CT. In the middle, signals recorded during the coronary functional assessment were shown in the blue rectangle. For both rest and hyperemic conditions CBF (Q) and CA resistance (R) were assessed. Aortic pressure wave signal was used to extract patient values to rescale both aortic and left ventricular pressure waves taken from literature¹⁴. On the bottom, the purple rectangle enclosed a schematic representation of the lumped-parameter model. Each arterial segment was represented by the circuit highlighted in gray, aortic BCs were defined by the Windkessel circuit colored in orange, and the BC of the CAs were defined in the blue dashed rectangle.