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Noninvasive assessment of pulmonary vascular resistance by doppler echocardiography
Background: The ratio of tricuspid regurgitation velocity (TRV) to the time-velocity integral of the right ventricular outflow tract (TVIRVOT) has been studied as a reliable measure to distinguish elevated from normal pulmonary vascular resistance (PVR). The equation TRV/TVIRVOT x 10 + 0.16 (PVRecho) has been shown to provide a good noninvasive estimate of PVR. However, its role in patients with significantly elevated PVR (> 6 Wood units [WU]) has not been conclusively evaluated. The aim of this study was to establish the validity of the TRV/TVIRVOT ratio as a correlate of PVR. The role of TRV/TVIRVOT was also compared with that of a new ratio, TRV 2/TVIRVOT, in patients with markedly elevated PVR (>6 WU).
Methods: Data from five validation studies using TRV/TVIRVOT as an estimate of PVR were compared with invasive PVR measurements (PVR cath). Multiple linear regression analyses were generated between PVRcath and both TRV/TVIRVOT and TRV2/TVIRVOT. Both PVRecho and a new derived regression equation based on TRV2/TVIRVOT: 5.19 x TRV 2/TVIRVOT - 0.4 (PVRecho2) were compared with PVRcath using Bland-Altman analysis. Logistic models were generated, and cutoff values for both TRV/TVIRVOT and TRV2/TVIRVOT were obtained to predict PVR > 6 WU.
Results: One hundred fifty patients remained in the final analysis. Linear regression analysis between PVRcath and TRV/TVIRVOT revealed a good correlation (r = 0.76, P <.0001, Z = 0.92). There was a better correlation between PVRcath and TRV2/TVIRVOT (r = 0.79, P <.0001, Z = -0.01) in the entire cohort as well as in patients with PVR > 6 WU. Moreover, PVRecho2 compared better with PVRcath than PVRecho using Bland-Altman analysis in the entire cohort and in patients with PVR > 6 WU. TRV2/TVIRVOT and TRV/TVIRVOT both predicted PVR > 6 WU with good sensitivity and specificity.
Conclusions: TRV/TVIRVOT is a reliable method to identify patients with elevated PVR. In patients with TRV/TVIRVOT > 0.275, PVR is likely > 6 WU, and PVRecho2 derived from TRV 2/TVIRVOT provides an improved noninvasive estimate of PVR compared with PVRecho.
History
Publication title
Journal of the American Society of EchocardiographyVolume
26Issue
10Pagination
1170-1177ISSN
0894-7317Department/School
Menzies Institute for Medical ResearchPublisher
MosbyPlace of publication
Inc, 11830 Westline Industrial Dr, St Louis, USA, Mo, 63146-3318Rights statement
Copyright 2013 American Society of EchocardiographyRepository Status
- Restricted