Reliability of Doppler echocardiography in the assessment of high pulmonary vascular resistance in patients with severe pulmonary arterial hypertension

Abstract Background The objective is to assess whether the squaring of tricuspid regurgitation velocity (TRV) gives an improved estimate of pulmonary vascular resistance (PVR) or is equivalent to the ratio of TRV and time velocity integral of right ventricular outflow tract (TVI RVOT ) (TRV/TVI RVOT ) for assessing PVR in patients with high PVR values. Methods Thirty patients predicted to have PVR >6 WU by Doppler were included in the present study. TRV and TVI RVOT were measured by echo Doppler. TRV/TVI RVOT and TRV 2 /TVI RVOT were calculated. PVR CATH was estimated within 2 h of Doppler study. Regression equations for calculating PVR from TRV/TVI RVOT (PVR ECHO1 ) and TRV 2 /TVI RVOT (PVR ECHO2 ) were developed. Bland–Altman analysis for agreement between PVR CATH and PVR ECHO1 , PVR ECHO2 was carried out. Results The mean value of PVR CATH was found to be 15.08 ± 7.03 WU. The calculated values of PVR ECHO1 and PVR ECHO2 were found to be 15.08 ± 6.34 WU and 15.05 ± 6.08 WU, respectively. The linear regression analysis carried out for PVR CATH and TRV/TVI RVOT showed good correlation (R = 0.84). Bland–Altman analysis showed excellent agreement between the two Doppler methods and invasive PVR with negligible bias. Conclusion Noninvasive estimation of PVR by Doppler is reliable even in patients with high PVR (>6 WU) and, squaring TRV is not superior to TRV alone.