Echocardiographic assessment of pulmonary vascular resistance in pulmonary arterial hypertension

Abstract

BackgroundEchocardiographic ratio of peak tricuspid regurgitant velocity to the right ventricular outflow tract time-velocity integral (TRV/TVI rvot) was presented as a reliable non-invasive method of estimating pulmonary vascular resistance (PVR). Studies using this technique in patients with moderate to high PVR are scarce. Left ventricular outflow tract time-velocity integral (TVI lvot) can be easier to measure than TVI rvot, especially in patients with severe pulmonary hypertension (PH) with significant anatomical modifications of the right structures.AimsWe wanted to determine whether the TRV/TVI rvot and TRV/TVI lvot ratios would form a reliable non-invasive tool to estimate PVR in a cohort of patients with moderate to severe pulmonary vascular disease.MethodsDoppler echocardiographic examination and right heart catheterisation were performed in 37 patients. Invasive PVR was compared with TRV/TVI rvot and TRV/TVI lvot ratios using regression analysis. Two equations were modelled and the results compared with invasive measurements using the Bland-Altman analysis. Using receiver-operating characteristics curve analysis, a cut-off value for the two ratios was generated.ResultsCorrelation coefficients between invasive PVR and TRV/TVI rvot then TRV/TVI lvot were respectively 0.76 and 0.74. Two new equations were found but the Bland-Altman analysis showed wide standard deviations (respectively 3.8 and 3.9 Wood units). A TRV/TVI rvot then TRV/TVI lvot ratio cut-off value of 0.14 had a sensitivity of 93% and a specificity of 57% for the first and a sensitivity of 87% and a specificity of 57% for the second to determine PVR > 2 Wood units.ConclusionEchocardiography is useful for the screening of patients with pulmonary hypertension and PVR > 2 WU. It remains disappointing for accurate assessment of high PVR. TVI lvot may be an alternative to TVI rvot for patients for whom accurate TVI rvot measurement is not possible.

A Simple Echocardiographic Method to Estimate Pulmonary Vascular Resistance

“…One study reported no benefit to using LVOT over RVOT-VTI. 10 In addition, CO is the product of stroke volume and heart rate. Integrating heart rate into the equation did not improve estimates.…”

Right Ventricular Outflow Tract Systolic Excursion: A Distinguishing Echocardiographic Finding in Acute Pulmonary Embolism

“…RVOT systolic excursion ¼ RVOT end-diastolic diameterÀRVOT end-systolic diameter RVOT end-diastolic diameter Pulmonary vascular resistance (PVR) was calculated using the following formula: 21,24 PVR =Peak tricuspid regurgitation velocity /RVOT velocity time integral ratio Quantitative assessment of the RV was obtained by measuring the end-diastolic RV area on the apical four-chamber image. A ratio of end-diastolic RV area to end-diastolic LV diameter ratio was then expressed as previously described.…”

Risk of Death and Need for Transplantation in Chronic Pulmonary Hypertension

“…The sample volume was placed so that the closing but not opening click of the pulmonary valve was visualized. 22,23 Pulsed-wave Doppler was used rather than continuous-wave Doppler to eliminate cases with increased pulmonary velocities secondary to either pulmonary valve or peripheral pulmonary artery stenosis and assess more accurately the duration of the signal. 14,22 Velocity time integral values were obtained by tracing the RVOT spectral pulsed Doppler signals, as previously described.…”