Quantitative Assessment Of Left Ventricular Function In Patients With Aortic Valve Replacement By Real-time Three-dimensional Echocardiography

Background and ObjectiveAortic valve disease is one of heart valve disease. The morbidity of it is highnowadays and age of onset is gradually younger. Aortic valve disease includes threetypes, aortic stenosis(AS),aortic regurgitation(AR),mixed aortic valve disease(MAVD) which is aortic stenosis with moderate to severe aortic regurgitation oraortic regurgitation with moderate to severe aortic stenosis. Aortic valve disease isassociated with rheumatic inflammation, and caused by congenital aortic valvemalformation, valve degeneration with old age, secondary to trauma, hypertension,aortic dissection and so on. Aortic valve disease are subjected to chronic volumeoverload or (and) pressure overload, leads to left ventricular hypertrophy anddamages left ventricular systolic and diastolic function. Aortic valve replacement(AVR) is one of effective way to reduce left ventricular volume overload and pressureoverload, restraint left ventricular remodeling and improve cardiac function.The methods of evaluating aortic valve disease by echocardiography aretwo-dimensional echocardiography, Doppler echocardiography, strain rate imaging,speckle tracking imaging, stress echocardiography and so on, but all of these can notreflect morphosis of aortic valve and volume of left ventricle really and directly. Real-time three-dimensional echocardiography (RT3DE) is considered as a milestonein the development of three-dimensional technology.RT3DE has great significance indiagnose and treat of cardiovascular disease. It can not only display live3D dynamicimage of heart structure, but also display chamber size, valve sharp and movement,spatial relation of heart structure. Most studies have focused on the sharp of leftventricle by RT3DE, but few studies have reported the change of left ventriculargeometry pre-and post-AVR in different aortic valve disease.The objective of the study is to assess the value of RT3DE in left ventriculargeometry and function in patients with different aortic valve disease.Methods1. Study population The study population included30healthy subjects(18men and12women; mean age,41.9±12.4years),50subjects (29men and21women;mean age,46.9±16.9years)who have accepted aortic valve replacement betweenaugust,2012and october,2013. They were divided into2groups according to aorticvalve disease,28aortic regurgitation (Group B) without moderate to severe aorticstenosis,22aortic stenosis(Group C) without moderate to severe aortic regurgitation.Both of the two groups were diagnosed without coronary artery disease, hypertension,myocardiopathy, diabetes mellitus and other heart disease according to coronaryangiography, electrocardiogram and echocardiography. The30healthy subjects werefrom health examination people, confirmed without any other related heart disease byphysical examination and echocardiograpy. Healthy subjects and patients with aorticvalve replacement were measured by RT3DE before operation,1week,1month and6month after operation.2. RT3DE measurement RT3DE was performed with Philips iE33, X5-1matrix array transducer, frequency1～5MHz. All subjects were taken left-lateralposition, connected electrocardiogram, Vmax, PPG of aortic valve were measured byusual echocardiography. The optimized apical four-chamber view was obtainedduring full volume mode. Apical full-volume imaging of left ventricle was obtainedfor all objects during breathhold. Images were stored and exported offline to work station. LVM were measured by manual tracing of epicardial and endocardial bordersof left ventricle in four-chamber view and two-chamber view at the end-diastole inQLAB9.03DQ software.LV segmentation was performed using3DQ Advanced inthe same way. Five endocardial points of four-chamber view and two-chamber viewat mitral valve level, one LV apical point were placed as landmarks. A series of LVparameters were displayed. Left ventricular end-diastolic volume(LVEDV),end-systolic volume(LVESV),ejection fraction(LVEF). Body surface area (BSA) ofsubjects was used to reduce the influence of height, weight and other factors to themeasured data. The LVEDVI was obtained by calculating the ratio of LVEDV to BSA,the LVESVI was obtained by calculating the ratio of LVESV to BSA, the LVMI wasobtained by calculating the ratio of LVM to BSA, and the LVRI was obtained bycalculating the ratio of LVM to LVEDV.3. Statistical analysis All data were expressed as mean±standard deviation.All the analyses were performed with SPSS17.0for windows. Differences in andamong groups were examined using one-way analysis of variance (ANOVA). For thecorrelation of different parameters, Pearson correlation analysis was used. P<0.05was considered to indicated a statistically significant result. Drawing analysis ofBland-Altman was used to determine interobserver and intraobserver variability.Results1. Comparison among groupsNo significant differences in age, height, weight, BSA, HR were found betweencontrol group and aortic valve disease group (P>0.05).LVMI and LVRI hadsignificant differences in three groups before operation,1week,1month and6monthafter operation. LVMI and LVRI in group B and group C were significantly higherthan group A (P<0.05).Vmax and PPG in group C were significantly higher thangroup A and group B before operation (P<0.05), while Vmax and PPG in group B andgroup C were significantly higher than group A after operation (P<0.05).LVEDVI and LVESVI in group B were significantly higher than group A andgroup C before operation(P<0.05).LVEDVI and LVESVI had no significant differences among three groups1week,1month and6month after operation(P>0.05).LVRI in group B and group C had significant differences before and1weekafter operation (P<0.05).2. Comparison in groupsLVEDVI,LVESVI,LVMI in group B and LVMI, Vmax, PPG in group Csignificantly decreased after1week of AVR compared with pre-operation(P<0.05),LVRI in group B and group C had significant differences1week of AVR comparedwith pre-operation (P<0.05).LVMI and LVRI in group B significantly decreased1month of AVR compared with1week of operation (P<0.05), while LVMI and LVRIin group C had no significant differences(P>0.05).LVMI and LVRI in group B andgroup C had no significant differences6month of AVR compared with1month ofAVR (P>0.05).3. Correlation analysisLinear correlation analysis showed negative correlation between LVEF andLVMI after1week,1month and6month of AVR (r=-0.68,P<0.05; r=-0.73,P<0.05;r=-0.88,P<0.05).4. Three-dimensional intra-and inter-observer variabilityDrawing analysis of Bland-Altman showed good intra-and inter-observeragreement for LVMI, LVEDVI and LVRI.Conclusions1. RT3DE could quantitatively assess left ventricular remodeling and function.2. AVR could reverse left ventricular remodeling in patients with different aorticvalve disease. For AVR, aortic regurgitation group is better than aortic stenosis group.3. LVEF and LVMI have higher correlation in different time of AVR. It indicatesthat left ventricular mass index on RT3DE could quantitatively evaluated leftventricular remodeling and function.