Objective: To explore and evaluate the characteristics of spectra wave shapes and parameters of the superior vena cava (SVC) Doppler flow patterns in patients with pulmonary arterial hypertension(PAH) by echocardiography.
Methods: Forty-nine patients with PAH as the PAH group and the paired healthy subjects as the control group were included in this study. Transthoracic echocardiography was used, and the spectra of SVC flow Doppler velocities in the right supraclavicular fossa view were examined and recorded. Peak velocity and velocity time integral (VTI) were measured.
Results: The spectra wave shapes of SVC flow velocity in the PAH group were distinguished from those of the control. The peak velocity and VTI of S waves during inspiration and the rate of respiratory changes of peak velocity of SVC flow Doppler velocity in moderate and severe PAH groups were significantly lower than those of the control (P<0.05).The peak velocity and VTI of D waves of SVC flow Doppler velocity in the PAH groups were significantly lower than those of the control (P<0.05). The rate of respiratory changes of peak velocity of D waves in the PAH groups was significantly lower than those of the control (P<0.05). The peak velocity and VTI of AR, and VR waves of SVC flow Doppler velocity in the PAH groups were significantly higher than those of the control (P<0.05). Linear regression analysis revealed a significant correlation between pulmonary arterial systolic pressure(PASP) and the Vexp/Vins ratio (r=0.760, P<0.001).
Conclusion: The spectra wave shapes of SVC flow velocity in the PAH groups were distinguished from those of the control which may have some diagnostic value for PAH.The peak velocities and VTI of S waves during inspiration, D waves, AR waves and VR waves of SVC flow Doppler in the PAH groups are different from the control. The ratio of Vexp/Vins of S wave may be a non-invasive quantitative index to detect PAH.