Evaluation Of Right Ventricular Remodeling In Patients With Pulmonary Hypertension Using Single Cardiac Cycle Real-time Three-dimensional Echocardiography

Objective：To evaluate right ventricular(RV) remodeling in patients withpulmonary hypertension(PH) using single cardiac cycle real-timethree-dimensional echocardiography (sRT-3DE)，and to explore the influencefactors of right ventricle/left ventricle(RV/LV) ratio，also the relationshipbetween RV remodeling and systolic function measured by sRT-3DE.Methods：1A total of40patients with PH were enrolled in this study and27age andgender-matched healthy subjects were included as control groups. TheRV/LV ratio were determined in the parasternal view.According to the RV/LVratio=0.8the patients were divided into two groups.No patient had pulmonarystenosis，right ventricular outflow tract obstruction，congenital heart disease，other organic heart disease and left ventricular ejection fraction<50%.All the healthy individuals determined by the clinical characters，chestX-ray， electrocardiogram and echocardiography.All the subjects are sinusrhythm.2SRT3DE was performed in all the subjects using a SIEMENS ACUSON2000ultrasound machine with a4Z1c probe and with RVA automatic analysissoftware to analyze right ventricular function.3Echocardiograms were obtained with the patients in the left lateral decubitusposition. All the subjects are linked with electrocardiogram. Firstly，gender，age and heart rate were recorded， all the echocardiography views andmeasurements were made according to the standard view of echocardiography.Finally， during a brief breath hold， the4D mode was activated and theapical four-chamber view was got，a full-volume3D image of the rightventricle was acquired (2beats) and all the datesets were saved on a hardware for analysis.4Image analysis and parameters measurement4.1parameters of conventional two-dimensional echocardiography and rightventricular function4.1.1RV/LV ratio was calculated by measurement of the maximum right andleft ventricular end-diastolic diameter， and the main pulmonary arterydiameter (MPA)，right atrium diameter (RAD)was measured as right heartstructure parameters.4.1.2Pulmonary artery systolic pressure（PASP）was estimated from the peakcontinuous-wave Doppler velocity of the tricuspid regurgitation jet plusright atrial pressure (assessed by inferior vena cava diameter and inspiratorycollapsibility). And mean pulmonary artery pressure (MPAP) were estimatedfrom early diastolic velocity of the pulmonary insufficiency jet(eDVPI) andright atrial pressure.4.1.3RV outflow velocity-time integra（lVTIRVOT）was determined from theVTI of pulsed-wave Doppler in the RV outflow tract. PVRe and correctedPVRe are based on the PVR equation: PVRe=TRV(m/s)/VTIRVOT（cm）×10+0.16(where TRV is tricuspid regurgitation velocity) and PVRe（wood）=3.2×PVRe-4.5.4.1.4Firstly，tricuspid annular plane systolic excursion(TAPSE) is obtained inthe apical four-chamber view by placing the sample-volume at level of lateraltricuspid annulus under Mode echocardiography’s guidance.Then TVI modewas activated，isovolumic relaxation time(IRT)，isovolumetric contractiontime(ICT) and ejection time (ET) were measured with the Doppler samplevolume positioned at the lateral margin of the tricuspid annulus. Tei index isbased on the equation：Tei=ICT+IRT/ET.4.1.5Inferior vena cava (IVC) diameter and its inspiratory collapsibility wasdetected by subcostal view.4.2Parameters measurement of three-dimensional volume of right ventricleThe images were extracted from ACUSON SC2000workstation and putinto the RVA automatic analysis software.Following the action menu， parameters including RV global end-diastolic volume (EDVRV)， end-systolicvolumes (ESVRV)，stroke volume (SVRV)，and ejection fraction (EF) werecalculated.Results：1Comparison of general clinical parametersNo significant difference was found in gender and age among the threegroups. There were statistically significant differences for resting heart ratebetween the patient and control groups，and no significant difference wasfound for resting heart rate between the group A and group B.2Comparison of parameters of conventional two-dimensionalechocardiography and right ventricular function2.1Comparison of parameters of conventional two-dimensionalechocardiographyThere were statistically significant differences for MPA and RA diameteramong the three groups. MPA and RA diameter were significantly increasedin the patient compared with those in the controls.2.2There were statistically significant differences for PASP， MPAP，PVRand moderate to severe tricuspid regurgitation beteen between the group A andgroup B.2.3There were statistically significant differences for TAPSE among the threegroups，and TAPSE is lower with the increasment of RV/LV ratio.2.4There were statistically significant differences for Tei index among thethree groups，and Tei index is greater with the increasment of RV/LV ratio.3Comparison of parameters of three-dimensional volume of right ventricleamong the three groupsThere were statistically significant differences for EDVRV，ESVRVandRVEF3D between the patient and control groups，and no significant differencewas found for SVRVbetween the group A and group B.No statistical significance for RVEF3D was found between the group A andcontrol groups. There were statistically significant differences for RVEF3Dbetween the group A and control groups. There were statistically significant differences for EDVRV，ESVRV，RVEF3D between the group A and groupB(P<0.05， P<0.05， P<0.01， respectively).4Correlation between RV/LV ratio and right ventricular structural andfunctional parametersThere are the positive correlation between RV/LV ratio and RAD，PASP，MPAP and moderate to severe tricuspid regurgitation.There are thenegative correlation between RV/LV ratio and TAPSE which could reflectright ventricular systolic function（r=-0.719）.And there are the positivecorrelation between RV/LV ratio and Tei index which could reflect rightventricular overall function(r=0.681).5Correlation between RVEF3D and right ventricular structural and functionalparametersThere are the negative correlation between RVEF3D and RV/LV ratiowhich could reflect right ventricular remodeling；and PASP，MPAP and PVR.There are the positive correlation between RVEF3D and TAPSE whichcould reflect right ventricular systolic function (r=0.695) and there are thenegative correlation between RVEF3D and Tei index which could reflectoverall function(r=-0.466).6Multiple stepwise regression analysis on RV/LV ratioRV/LV ratio as the dependent variable，PASP，MPAP，PVR andmoderate to severe tricuspid regurgitation as independent variables， bymultiple stepwise regression analysis， PASP and MPAP are variableentering the equation．That show PASP and MPAP are the main factors whichcould affect the RV/LV ratio.7Multiple stepwise regression analysis on RVEF3DRVEF3D as the dependent variable，RV/LV ratio，PASP，MPAP andPVR as independent variables，by multiple stepwise regression analysis，MPAP is the only variable entering the equation．That show MPAP is themain factors which could affect the RVEF3D.Conclusions:Right ventricular remodeling and right ventricular systolicfunction decreasing are common characteristic in all the patients with pulmonary hypertension. And sRT-3DE can be used to quantitatively andaccurately assess right ventricular systolic function，the RVEF3D measuredby sRT-3DE have good correlation with TAPSE and Tei index. Patients withPH whose RV/LV ratio>0.8have worse right ventricular systolic function. Bymultiple stepwise regression analysis，MPAP is the main factor which couldaffect the RVEF3D and MPAP and PASP are the main factors which couldaffect the RV/LV ratio.