Doppler flow spectra of the superior vena cava in a rat model of chronic pulmonary hypertension

The aim of this study was to explore the changes of the Doppler flow spectra of the superior vena cava (SVC) in a rat model of chronic pulmonary hypertension (PH). Thirty-two rats were injected with monocrotaline (MCT) to establish a model of chronic PH. Eight rats from the control group had a sham operation by injecting Dulbecco's phosphate-buffered solution. Serial echocardiographic parameters of the SVC were analysed four weeks after treating with MCT or placebo, and the relationship was analysed between the Doppler flow spectra of SVC and the pulmonary arterial systolic pressure (PASP). PH models were successfully established in 29 rats. The right ventricular systolic pressure, mean pulmonary arterial pressure and PASP in the PH group were significantly higher than those in the sham group at 28 days (P < 0.001). The ratios of SVC maximum reverse peak flow velocity/maximum systolic peak flow velocity (VAr/VS) and maximum reverse peak velocity time integral/maximum systolic peak velocity time integral (VTIAr/VTIS) increased significantly (P < 0.05) after MCT injection. These results demonstrate that echocardiography can be used to monitor the haemodynamic changes in SVC in MCT-induced chronic PH rat models. The ratios of VAr/VS and VTIAr/VTIS may be sensitive indices for evaluating PH.