The Age of Non-Invasive Measurements: Echocardiographic Equations Methods to Determine Variables in the Pulmonary Vascular Reactivity Test

Introduction and objectives: Right Heart Catheterization (RHC) is a gold method to perform the Pulmonary Vascular Reactivity Test (PVRT), however echocardiography has proven effective in estimating different hemodynamic variables. This study to demonstrate that with the Doppler echocardiographic index: Tricuspid Regurgitation Maximum Velocity (TRV)/Time-Velocity Integral of the Right Ventricle Outflow Tract (TVIrvot) we will obtain a Pulmonary Vascular Resistance Value (PVR) comparable to the invasive method. We evaluate its applicability in the PVRT. Methods: Prospective, double-blind, observational study in 30 patients, performed in 2 stages: A) We obtained simultaneous measurements of PVR by invasive method and echocardiography. TRV/TVIrovt index measurements were correlated with invasive PVR using the analysis of linear regression. An equation was modeled to calculate PVR in Wood Units (WU) by echocardiography; the results were compared with invasive RVP measurements using the Bland-Altman analysis. B) TRVP was performed by simultaneous measurement of PVR and Pulmonary Arterial Mean Pressure (MPAP) with the echocardiographic and invasive method. We use the equation formulated by Abbas (RVPa) and another modified one proposed in this study (RVPt). Results: In the first stage, the TRV/TVIrotv ratio correlated well with invasive PVR measurements (R2 =0.92). The Bland Altman analysis using RVP=10 × VRT/TVIrvot+0.36 showed satisfactory agreement limits (mean ± 0.36, L: 0.12-0.61). In the TRVP there was a high correlation of PVR between the two methods using the two equations. We also found high correlation with MPAP. Conclusions: The Doppler echocardiogram offers a reliable and non-invasive method to measure the PVR and MPAP in the PVRT.