Real-time Three-dimensional Echocardiographic Assessment Of Left Ventricular Remodeling Index And Heart Function In Patients With Coronary Artery Disease

PrefaceThe morbidity and mortality of coronary artery disease(CAD)has rapidly increasedwith the improvement of the standard of living and the development of the aging.According to investigations of population,there are 60,000,000 cases of CAD in China,andthe cases dead of CAD were more than 1,000,000 every year.In recent decade,Themorbidity rate of man and women increased 26.1% and 19.0%,respectively,comparedwith the same period of last decade.Moreover,the patients with CAD become more young.The morbidity ratio among the youngs who were less than 40 years was 4.3% .Themorbidity ratio of young with CAD who are less than 35 years is continously increasing.CAD has been becoming one of diseases that seriously threaten the healthy of people.With progression of CAD and the increasing numbers of the involved coronaryarteries,left ventricle(LV) will develope modification in shape,size,and function whichare defined as left ventricular remodeling .These changes will play great role in diagnosing,making decisions and evaluating prognosis.Coronary artery bypass grafting(CABG) thatcan provide blood supply for the ischemic myocardium has become one of effectiveapproaches to treat CAD resulted by the entire closure or serious stenosis of coronaryartery.The bridge grafting artery can reopen the collateral circulation for ischemicmyocardium,which effectively results in restraining LV remodeling and improving LVfunction as well as reducing myocardial necrosis,restraining infarction areas and penetrate degree which improves or restores surviving myocardial (hibernation myocardium,stunnemyocardium and injured myocardium) function.Conventional 2DE has become first choice in asseement of LV remodeling and heartfunction because of its simpleness,convenience and reproducibility.The results measuredby 2DE is thought to be accurate in patients with normal LV shape which is assumpted as aregular geometric model.Then ,the regular geometric model volume of LV are measured atthe 2DE standard planes and calculated by a specific formula .However,the results isinaccurate under the condition of the changed shape of LV measured by 2DE as the actualshape of LV is totally different with the geometric model assumption.Previous clinicpractices had showed that conventional transthoracic 2DE were not ideal tool for accuratequantification of left ventricular volume as this method is subjected to two dimensionalplanes.RT-3DE can conveniently acquire the whole dataset of the stereo structures in theinteresting region and directly display the shape of the remodeled LV such as aneurysm.Recently,animal researches and clinic studies showed that RT-3DE had resolved majorlimitations of 2DE and could significantly improve the accuracy of these measurements ofLV volume,mass ,function and wall motion by a fast way.The results obtained byRT-3DE have good agreement with those obtained by Cardiac Magnetic Resonance(MRI).The aim of this study is to assess CAD's LV remodeling and its function before andafter CABG using parameters such as left ventricular remodeling index (LVRI),leftventricular ejection fraction(LVEF),regional peak ejection ratio(rPER),regional peakfilling ratio (rPFR),global peak ejection ratio (gPER),global peak filling ratio (gPFR)measured by RT-3DE.The dissertation includes three parts as following:Part 1 Real-time Three-dimensional Echocardiographic Assessment of LeftVentricular Remodeling Index in Patients with Coronary Artery DiseaseIn the part,according to the results of coronary artery angiography,single main vessel stenosis which was eqeal to or larger than 50% was defined as recruited standard ,RT-3DE was carried out in 24 patients with left circumflex coronary artery or/and rightcornary artery stenosis (LCX/RCA group),21 patients with left anterior descendingcoronary artery stenosis (LAD group),27 patients with double or triplex coronary arteriesstenosis which must include LAD(Vessels group)and 22 subjets (normal controls group).The rate of cases with angina,acute myocardial infarction,and old myocardial infarctionwas 1/3 in every CAD group ;and the rate of cases with mild,moderate,severe coronaryartery stenosis was 1/3 in every CAD group.Left ventricular end-diastolic volume(LVEDV),left ventricular end-diastolic epicardial volume (LVEDVepi),left ventricularejection fraction (LVEF) were automatically measured by 4D LV analysis CAP 2.5software of TomTec company;left ventricular mass [ LVM=1.05×(LVEDVepi-LVEDV)],LVRI (LVM/LVEDV)were calculated.All above parameters were measured andcalculated in the same manner by 2DE Simpson biplane method.The inter-group differencesof LVEDV,LVRI,LVEF measured by RT-3DE and 2DE;and the intra-group differencesand correlations of LVEDV,LVRI,LVEF between RT-3DE and 2DE;and the correlationsbetween RT-3DE LVRI and LVEF,LVRI and LVEDV;correlations between 2DE LVRI andLVEF LVRI and LVEDV in normal controls group,LCX/RCA group,LAD group ,andVessels group were analyzed.RESULTS RT-3DE and 2DE LVRI and LVEF significantlydecreased in order,LVEDV significantly increased in order in normal controls group,LCX/RCA group,LAD group and Vessels group,respectively.RT-3DE LVEDV:(74.82±10.43)ml vs (89.72±11.17) ml vs (101.27±19.58) ml vs (116.79±18.13) ml,RT-3DE LVRI:1.85±0.06 vs 1.75±0.11 Vs 1.64±0.15 vs 1.50±0.22 ,and RT-3DE LVEF:(63.26±4.93)%vs (55.34±7.24) % vs (49.30±9.74) % vs (42.17±11.55)%,( all P＜0.05 or P＜0.01);2DE LVEDV:(74.58±9.95)ml vs (87.76±8.99)ml vs (95.86±17.60)ml vs (110.30±17.68)ml,2DE LVRI:1.86±0.05 vs 1.78±0.12 vs 1.70±0.09 vs 1.59±0.17,and 2DE LVEF:(64.31±4.43) % vs (56.43±5.97) % vs (50.70±9.26) % vs (45.78±9.99) %;(all P＜0.05or P＜0.01).LVEDV.LVRI,LVEF measured by RT-3DE and 2DE were significant difference in LAD group and Vessels group ( P＜0.05 or P＜0.01);but no significantdifference in normal controls group and LCX/RCA group ( P＞0.05) .The correlationanalysis indicated that:1.There were significant correlations of LVEDV,LVRI,LVEFbetween RT-3DE and 2DE in normal controls group ,LCX/RCA group,LAD group andVessels group(r=059～0.99,all P＜0.01 ),except for LVRI measured by RT-3DE and 2DEin Vessels group(r=0.36,P＞0.05).2.There were significant correlations betweenRT-3DE LVRI and LVEF (r=0.86,0.82,0.74,all P＜0.01) ;between 2DE LVRI andLVEF(r=0.78,0.86,0.59,all P＜0.01) in LCX/RCA group,LAD group and Vessels group,respectively;but no significant correlation ( RT-3DE r=0.10,2DE r=0.28,all P＞0.05) innormal controls group.2.There were significant negative correlations between RT-3DELVRI and LVEDV (r=-0.49,-0.77,-0.91,all P＜0.05 or P＜0.01) ;between 2DE LVRIand LVEDV(r=-0.62,-0.83,-0.91,all P＜0.01) in LCX/RCA group ,LAD group andVessels group,respectively;but no significant conrelations ( RT-3DE r=0.12,2DE r=0.09,all P＞0.05)in normal controls group.The good agreement and reproducibility ofLVRI measured by RT-3DE were found superior to 2DE.Part 2 Clinical Study of Left Ventricular Regional and Global Function byReal-time Three-dimensional Echocardiographic Volume-time Curve in Patients withCoronary Artery DiseaseTo assess the feasibility and accuracy of RT-3DE VTC in quantifying regional andglobal left ventricular systolic and diastolic function in patients with CAD.According tocoronary artery angiography ,single main vessel stenosis eqeal to or larger than 50% wasdefined as positive standard .Full volumetric RT-3DE data of 24 patients with leftcircumflex coronary artery or/and right coronary artery stenosis (LCX/RCA group ) ,21patients with single left anterior descending coronary artery stenosis ( LAD group) ,27patients with double or triplex coronary arteries stenosis,which must include LAD(Vesselsgroup)and 22 subjects (normal controls group) were acquired.The rate of cases with angina, acute myocardial infarction,and old myocardial infarction was 1/3 in every CAD group ;and the rate of cases with mild,moderate,severe coronary artery stenosis was 1/3 in everyCAD group.The gPER,rPER,gPFR,rPFR and LVEF were obtained by 4D LV analysisCAP 2.5 software of TomTec company.RESULTS The gPER:(296.60±118.69) ml/s vs(225.49±89.52) ml/s vs (162.09±46.58) ml/s vs (95.80±47.46) ml/s,gPFR:(209.69±101.65) ml/s vs (152.75±69.66) ml/s vs (106.77±34.54) ml/s vs (58.88±30.60)ml/s,LVEF:(63.27±4.92)% vs (55.33±7.18)% vs (49.48±9.38)% vs (42.11±11.49)%significantly decreased in order ( all P＜0.05 or P＜0.01 ) in normal controls group,LCX /RCA group,LAD group,Vessels group,respectively.The other rPER,rPFR ofcorresponding sections where coronary artery had positive stenosis were significantlylower than those of corresponding sections where coronary artery had no positive stenosisinter-group ( P＜0.05 or P＜0.01 ),respectively,except rPFR of mid inferiorin in LAD groupand Vessels group,rPFR and or rPER of partial apical inferior,apical lateral and apex inLCX / RCA group,LAD group,and Vessels group.Correlation analysis indicated that goodpositive correlations between gPER and gPFR ( r =0.975,0.985,0.977,0.983,all P＜0.01),between gPER and LVEF ( r =0.980,0.878,0.951,0.972,all P＜0.01) in normal controlsgroup ,LCX/ RCA group,LAD group,Vessels group,respectively;The good positivecorrelations between rPER and rPFR of each section ( r=0.891～0.990,all P＜0.01)were found.Part 3 Real-time Three-dimensional Echocardiographic Analysis of LeftVentricular Remodeling Index and Heart Function in Evaluating the Effect ofCoronary Artery Bypass GraftingTo evaluate the effect of CABG with left LVRI and heart function using RT-3DE.22 normal control subjects (normal control group) and 30 patients with CABG group( including pre-CABG ,one week after CABG ,one month after CABG subgroups) ofRT-3DE full volumetric dataset were acquired.LVEDV,LVESV,LVEDVepi,The gPER, gPFR,and LVEF in all cases were offline obtained by 4D LV analysis CAP 2.5 software ofTomTec company;LVM,LVRI were calculated.Then,the differences of LVRILVEF ,gPER,gPFR between normal controls group and CABG subgroup,betweenpre-CABG subgroup and one week after CABG subgroup/ one month after CABGsubgroup;the correlations between LVRI and gPER,LVRI and LVEF,gPER and gPFR innormal controls group ,CABG group were compared with.RESULTS LVRI ,LVEF ,gPER,gPFR of pre-CABG ,one week after CABG ,one month after CABG subgroupswere significant lower than those of normal controls group ( P＜0.05 );LVRI ,LVEF ,gPER,gPFR of one month after CABG subgroup were significant greater thanthose of pre-CABG subgroup,one week after CABG subgroup( P＜0.05 );but LVRI ,LVEF,gPER,gPFR of one week after CABG subgroup weren't significant dittiences fromthose ofpre-CABG subgroup ( P＞0.05 ).Correlation analysis indicated that good positivecorrelations between LVEF and gPER,between gPER and gPFR in normal control groupand CABG group;good positive correlations between LVRI and LVEF,LVRI and gPER inpre-CABG subgroup ,one week after CABG subgroup and one month after CABGsubgroup,but no good positive correlations between LVRI and LVEF,between LVRI andgPER in normal controls group were found.CONCLUSIONS:1.LVRI measured by RT-3 DE and 2DE can assess CAD' s left ventricular remodeling,and reflect its left ventricular systolic function;RT-3DE LVRI can take as a newapproach for evaluating left ventricular remodeling in clinic superior to 2DE.2.RT-3DE VTC can provide a new noninvasive and accurate tool for assement of LVregional and global diastolic and systolic function in CAD with gPER,gPFR,rPER,rPFR,LVEF parameters.3.RT-3DE can combinely assess left ventricular remodeling and heart function changesin patients with CAD by measuring LVRI,gPER,gPFR,LVEF. 4.RT-3DE is a new tool for clinical evaluation of CABG effects by combinely measuringLVRI,gPER,gPFR,LVEF before and after CABG.