Extension of Doppler-derived echocardiographic measures of pulmonary vascular resistance to patients with moderate or severe pulmonary vascular disease

Background: Pulmonary vascular resistance (PVR) is a critical parameter in the assessment and treatment of patients with pulmonary hypertension, regardless of origin. Noninvasive estimation of PVR could be helpful. Methods: Consecutive patients with known or suggested pulmonary hypertension referred for cardiac catheterization were evaluated prospectively and the PVR was calculated invasively. Subsequently, the tricuspid regurgitation velocity (TRV), the velocity-time integral (mean of 3 measurements) of the right ventricular outflow tract (VTIm), and the right ventricular outflow tract diameter were recorded noninvasively. Results: The TRV/VTIm ratio and the TRV/VTIm corrected for the indexed RVOT diameter correlated well with the PVR at catheterization with R-2 = 0.711 and R-2 = 0.731, respectively, including patients with very high values of PVR. A TRV/VTIRVOT value of 38 provided a specificity of 100% for a PVR of 8 Woods units. Conclusion: Noninvasive estimation is feasible over a broad range of PVR values and could be a useful tool to estimate and longitudinally tracked changes in PVR.