Echocardiographic Estimation of Pulmonary Vascular Resistance in Chronic Thromboembolic Pulmonary Hypertension: Utility of Right Heart Doppler Measurements

Authors

  • Yu Xie M.D.,

    1. U.C. San Diego School of Medicine and Sulpizio Cardiovascular Center, University of California San Diego, La Jolla, CA
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  • Benita M. Burke M.D.,

    1. U.C. San Diego School of Medicine and Sulpizio Cardiovascular Center, University of California San Diego, La Jolla, CA
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  • Alex Kopelnik M.D.,

    1. U.C. San Diego School of Medicine and Sulpizio Cardiovascular Center, University of California San Diego, La Jolla, CA
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  • William Auger M.D.,

    1. U.C. San Diego School of Medicine and Sulpizio Cardiovascular Center, University of California San Diego, La Jolla, CA
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  • Lori B. Daniels M.D.,

    1. U.C. San Diego School of Medicine and Sulpizio Cardiovascular Center, University of California San Diego, La Jolla, CA
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  • Michael M. Madani M.D.,

    1. U.C. San Diego School of Medicine and Sulpizio Cardiovascular Center, University of California San Diego, La Jolla, CA
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  • David S. Poch M.D.,

    1. U.C. San Diego School of Medicine and Sulpizio Cardiovascular Center, University of California San Diego, La Jolla, CA
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  • Nick H. Kim M.D.,

    1. U.C. San Diego School of Medicine and Sulpizio Cardiovascular Center, University of California San Diego, La Jolla, CA
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  • Daniel G. Blanchard M.D.

    Corresponding author
    1. U.C. San Diego School of Medicine and Sulpizio Cardiovascular Center, University of California San Diego, La Jolla, CA
    • Address correspondence and reprint requests: Daniel G. Blanchard, M.D., UCSD Sulpizio Cardiovascular Center, 9444 Medical Center Drive, #7411, La Jolla, CA 92037, USA. Fax: 858 657-5012;

      E-mail: dblanchard@ucsd.edu

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Abstract

The ratio of tricuspid regurgitation velocity divided by the velocity-time integral of right ventricular outflow tract pulsed-wave Doppler tracing (TRV/VTIRVOT) has been used to estimate pulmonary vascular resistance (PVR). However, this method has not been validated in chronic thromboembolic pulmonary hypertension (CTEPH). We assessed the utility of TRV/VTIRVOT in patients with CTEPH and PVR from 2 to 20 WU. All had right heart catheterization (RHC) within 2 days of echocardiography. TRV/VTIRVOT was calculated and RHC-derived pressures, PVR, and cardiac outputs were recorded. Mean pulmonary artery pressure was 47 ± 12 mmHg, cardiac output: 4.2 ± 1.1 L/min, PVR: 9 ± 4 WU, right atrial pressure: 12 ± 6 mmHg. Mean VTIRVOT was 13 ± 5 cm; mean TRV was 4.2 ± 0.8 m/s, mean tricuspid regurgitation severity was 2.5 ± 0.8 (1 = trace, 2 = mild, 3 = moderate, 4 = severe). Regression analysis demonstrated a correlation between RHC PVR and TRV/VTIRVOT: PVR = 19.4 × (TRV/VTIRVOT) + 2.4 (r = 0.74, P < 0.001). However, Bland–Altman analysis found a poor degree of agreement between echo-derived PVR and RHC PVR. We also studied 28 patients with non-CTEPH pulmonary hypertension. Similar analysis revealed a regression equation of PVR = 20.1 × (TRV/VTIRVOT) + 0.3 (r = 0.57, P < 0.01). Conclusion: TRV/VTIRVOT is only marginally useful for estimating PVR in CTEPH (r = 0.74). Moreover, the regression equation in CTEPH differs significantly from previous studies in pulmonary hypertension. Reasons for this may include the markedly elevated PVR levels in this population and specific effects on VTIRVOT from CTEPH.

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