Characteristics Of Pulmonary Arterial Flow Derived From Phase Contrast Magnetic Resonance Imaging In Patients With Pulmonary Arterial Hypertension: Correlations With Right Ventricular Function And Hemodynamics

Background: The phage contrast cardiac magnetic resonance (CMR) can encode the flow character, which enables flow velocity and volume to be assessed. We designed this prospective study to validate that pulmonary artery (PA) net forward flow measured by phase contrast CMR could be a useful parameter to assess right ventricle stoke volume noninvasively in pulmonary arterial hypertension (PAH) patients. Methods: PAH patients were observed prospectively. Right heart catheterization (RHC), echocardiogram and CMR were performed within one week. Correlations between parameters derived from phase contrast CMR, and right ventricular function and hemodynamics derived from RHC and echocardiogram were analyzed. Results: Thirty PAH patients were enrolled. Average pulmonary arterial (PA) velocity (r=0.455, P= 0.011; r=-0.575, P=0.001), PA forward flow volume (PA_FFV_PC, r=0.465, P=0.010; r=-0.532, P=0.003), PA net forward flow volume (PA_net FFV_PC, r=0.492, P=0.006; r=-0.592, P=0.001) all had significant positive correlations with TAPSE and negative correlations with PVR. At the same time, PA_FFV_PC (r=-0.392, P= 0.036) and PA_ net FFV_PC (r=-0.420, P=0.023) also had significant negative correlations with N-terminal pro brain natriuretic peptide. PA_ FFV_PC (r= 0.732, P<0.001), PA_ net FFV_PC (r=0.764, P<0.001), aortic forward flow volume (Ao_FFV_PC, r=0.737, P<0.001), aortic net forward flow volume (Ao_ net FFV_PC, r=0.733, P<0.001) all had significant positive correlations with RV stroke volume (RVSV_RHC) which also must be measured invasively. Bland-Altman analysis showed that PA_net FFV_PC and Ao_net FFV_PC had good consistency with RVSV_RHC. Conclusions: PA flow characteristics can reflect right heart function of PAH patients, and PA_ net FFV_PC also had a good consistency with RVSV_RHC.