The Characteristics Of The Spectra Of Superior Vena Cava Flow Doppler Velocities In Pulmonary Arterial Hypertension

Objective:To explore and evaluate the characteristics of spectra wave of the superior vena cava(SVC)Doppler flow patterns in patients with pulmonary arterial hypertension by echocardiography.Methods:Fourty-nine patients with pulmonary arterial hypertension (PAH)as the PAH group and the paired healthy subjects as the control group were recruited.According to the level of Pulmonary artery systolic Pressure(PASP),the patients were divided into 3 groups.Mild PAH group: 30mmHg≤PASP＜50 mmHg,Moderate PAH group:50mmHg≤PASP＜70 mmHg,Severe PAH group:PASP≥70 mmHg.The spectra of Superior Vena Cava flow Doppler velocities in the right supraclavicular fossa view were measured by Transthoracic echocardiography.Maximum and minimum return flow velocity spectra of SVC in respiration cycle were recorded,peak velocities and their velocity time integrals(VTI)were measured also,and the respiratory changes of the parameters Of the spectra of SVC were calculated.Linear regression was analysed between PASP and the Vexp/Vins ratio of S wave.Results:1.The spectra wave shapes of SVC flow velocity in the group with PAH were different from those of healthy subjects,D waves were lower than those of the control,and AR waves,VR waves in PAH groups significantly higher than those of the control,and the S waves during inspiration were lower than those of the control.2.The peak velocities and VTIs of S waves at inspiration and the changes of peak velocities of SVC flow Doppler velocities during respiratory in Moderate and Severe PAH groups were significantly lower than those of the control(p＜0.05);Linear regression analysis revealed a significant correlation between PASP and the Vexp/Vins ratio(r=0.760, P=0.000).The peak velocities and VTIs of D waves of SVC flow Doppler velocities in all PAH groups were significantly lower than those of the control(p＜0.05),also,the changes of peak velocities of D waves during respiratory in PAH groups significantly lower than those of the control(p＜0.05).The peak velocities and VTIs of AR,VR waves of SVC flow Doppler velocities in PAH groups were significantly higher than those of the control(p＜0.05).Conclusion:1.The spectra wave shapes of SVC flow velocity in the group with PAH were different from those of control,D waves were lower than those of the control,and AR waves,VR waves in PAH groups significantly were higher than those of the control,also,the S waves during inspiration were lower than those of the control.These findings may have a diagnositic value for pulmonary hypertension.2.The peak velocities and VTIs of S waves during inspiration,D waves,AR waves and VR waves of Superior Vena Cava flow Doppler in the groups with PAH were different from the control,the ratio of Vexp and Vins in S waves of SVC flow Doppler may provide a non-invasive index to diagnosis pulmonary arterial hypertension.