New Model for Non-Invasive Echocardiographic Assessment of Pulmonary-Capillary Wedge Pressure in Patients With Aortic and Mitral Regurgitation

Abstract

The pulmonary-capillary wedge pressure (PCWP) is a central parameter of cardiac function. In this work, we propose an equation based on a simple physical model, which should be applicable to any class of patient, provided they present some level of aortic and mitral regurgitation. We modeled the left cardio-circulatory system as three chambers placed in a series as follows: left atrium (LA), left ventricle (LV), and aorta (A). Starting from the principle of energy conservation, knowing pressure gradient between A and LV (transaortic gradient) and between LV and LA (trans mitral gradient), we can measure blood pressure in A with a non-invasive central blood pressure (BP) analysis device and then we can derive pressure in LA. With the model described, we derive the equation PCWP ≈ {[(systolic central BP + 4 maximal aortic valve outflow velocity2) − 4 maximal mitral valve regurgitation jet velocity2] + [(diastolic central BP − 4 telediastolic aortic valve regurgitation jet velocity2) + mean mitral valve inflow gradient]} / 2. Herein, we propose a new model for PCWP determination using Doppler echocardiography and a non-invasive central blood pressure (BP) analysis device. One of the main advantages of the method we proposed is that, given it is based on a simple physical model instead of multilinear regression, it should be applicable to any class of patient, provided they present some level of aortic and mitral regurgitation. Further studies are needed for its validation by parallel analysis using invasive methods.