Investigation On The Ventricular Function In TOF Patients Using Echocardiographic Novel Techneques

Background.Tetralogy of Fallot(TOF) is one of the most frequent abnormalities in cyanotic congenital heart disease.Echocardiography is the most important diagnostic method. Although 2-Dimensional echocardiography(2DE) has high accuracy in displaying directly its anatomic structure,its evaluation effect is influenced by acoustic window.There are only a few of articles about cardiac function pre- and post-operation in TOF,but there is always dispute about it.Control study between pre- and post-operation is very important for clinic diagnosis.Recent real-time three-dimensional echocardiography(RT-3DE) is an effective method in evaluating cardiac morphology and function,with providing more three-dimensional anatomic information than 2DE.Some researchers measured the volume of left ventricle(LV) and right ventricle(RV) using RT-3DE,and found that the values using RT-3DE correlates well with the actual values,indicating that RT-3DE is a perfect technique in evaluating ventricular volume and function in dynamic and real-time condition.Tei index is a novel index to detect global cardiac function.The usage of conventional Tei index(C-Tei) derived from Doppler technique is limited because of poor sampling clarity.Tissue Doppler imaging(TDI) was introduced to calculate Tei-index(TDI-Tei) in 1990s,and soon was applied owing to clear sampling.It is considered that TDI-Tei index is more sensitive and accurate than C-Tei in evaluating RV function and is a perspective method for cardiac function.ObjectiveTo evaluate LV and RV morphology and systolic function of TOF before operation and at different time point after operation with RT-3DE,to evaluate the global function with TDI-Tei and C-Tei index;and to assess the systolic and diastolic function changes preand post operation(post-op) with TDI velocity at mitral and tricuspid annulus,and to evaluate the feasibility of RT-3DE and TDI-Tei index for evaluating LV and RV function at the same time.MethodsFifty four patients with TOF proved by surgery were studied during October 2006 to July 2007 and thirty of them with full data(mean age 9±7 years) were enrolled in evaluation.Philips iE33 instrument with probe S5-1 and probe X3-1 was used to obtain 2-dimensional TDI-PW images and 3-dimensional full volume images in TOF patients.The images then were imported to QLAB5.2 workstation.Then LV and RV volume of end-diastole(EDV) and end-systole(ESV) and systolic function(ejection fraction,EF) were analyzed with QLAB5.2 3DQ Advance software(3DQA).TDI-PW images in mitral annulus and tricuspid annulus were used for measurement of time interval "a"' and "b"', blood flow frequency spectrum of mitral orifice and tricuspid orifice for time interval "a", LV outflow tract and RV outflow tract for "b" respectively.Then TDI-Tei index and C-Tei index were calculated.Systolic(Vs) and diastolic velocity(Ve and Va) of mitral and tricuspid annulus were measured and used as reference to analyze the change tendency of TDI-Tei index and C-Tei index.And Ve/Va was combined with systolic and global function parameters to assess diastolic function of LV and RV.Cardiac MRI images were obtained in ten cases of TOF before operation with 1.5T Infinit Twin Speed MR instrument(GE Corporation).After routine three-plane location scanning, apical four and two chamber's view were obtained,then short axis views were located vertical to interventricular septum(the line between mitral valve and Apex).Consecutive multiple plannar short axis images were obtained with Fiesta Cine series.With the help of postprosessing software package,outline the endocardium border of LV and RV,LV and RV volume and EF were calculated respectively and used as control standard of RT-3DE.Results:1.The mean RVEDV,RVESV,RVEF,LVEDV,LVESV and LVEF measured by RT-3DE had no statistic difference,compared with that by MRI in 10 preoperative TOF patients,with coefficient correlation was 0.996,0.997,0.95,0.996,0.998,0.950 respectively.2.RT-3DE clearly displayed the cross section area of RV outflow tract and pulmonary artery,area of ventricular septal defect,and the patch repairing the defect.The cross section area of RV outflow tract and pulmonary artery post operation(post-op) was significantly increased,compared with that of before operation(pre-op)(P＜0.05),and the defects of ventricular septum disappeared.3.RV functional abnormality:Although RVEF were decreased in some TOF patients before operation,the mean RVEF was not decreased significantly(P＞0.05).RVEDV at 12d post-op had no statistical difference(P＞0.05),while RVEF was markedly decreased(P＜0.05),compared with that of preoperation.RVEDV at 3mon post-op increased to some degree,but it had no statistical significance(P＞0.05),and RVEF increased to almost normal(P＞0.05).Compared with pre-op,the systole velocity(Vs),early(Ve) and late diastole velocity (Va) of lateral wall at mitral annulus decreased at 12d post-op(P＜0.05),while Ve/Va had no significant difference(P＞0.05),and Vs,Ve and Ve/Va at 3mon post-op increased (P＜0.05).There was no statistic difference between 12d and 3mon post-op(P＞0.05).Compared with preoperation,TDI-Tei index at 12d increased and 3mon post-op reduced(P＜0.05),and TDI-Tei index of 3mon post-op was reduced than that of 12d post-op (P＜0.05).Compared with TDI-Tei index,C-Tei index had no significant difference before operation(P＞0.05),but decreased markedly at 12d increased and 3 mon post-op(P＜0.05), that at 3 mon post-op was further decreased than 12d post-op(P＜0.05).The changing tendency of C-Tei index was different with TDI-Tei.4.LV functional abnormality:LV volume was in the low range before operation compared with normal reference data.LV volume increased markedly at 12d post-op(P＜0.05) and increased very markedly at 3mort post-op(P＜0.05,0.01 respectively),LVEF did not increase at 12d post-op(P＞0.05) but increased markedly at 3mon post-op(P＜0.05),although some patients still did not increase up to normal range.Compared with pre operation,TDI-Tei index at 12d increased and 3mon post-op were all decreased significantly(P＜0.05),and TDI-Tei index of 3mon post-op was diminished than that of 12d post-op(P＜0.05).Compared with pre operation,Vs had no significant difference(P＞0.05),Ve and Ve/Va increased significantly at 12d post-op(P＜0.05).Vs,Ve and Ve/Va at 3mon post-op increased significantly(P＜0.05).There was no statistic difference between 12d and 3mon post-op(P＞0.05).Compared with pre operation,C-Tei index at 12d increased and 3mon post-op were all diminished significantly(P＜0.05),that of 3mon post-op was further decreased than 12d post-op(P＜0.05).The changing tendency of C-Tei index was the same with TDI-Tei.Conclusion:1.RT-3DE provide LV and RV volumes and ejection fraction highly relative to that by MRI,indicate that RT-3DE can accurately quantify LV and RV volumes and ejection fraction.2.RT-3DE can clearly display the anatomic morphology and so can make more accurate diagnosis in TOF than 2DE and provide a new tool to evaluate cardiac morphology.3.Although RV global and diastolic function is impaired,systolic function is still normal before operation in TOF.RV volume doesn't improve obviously at 12 d and 3 mon after operation.RV systolic function and global function decrease at 12 d after operation, compared with preoperation,but RV diastolic function doesn't change.At 3 mon after operation,RV systolic function recover to the level of preoperation,but RV global is improved than that of 12 d after operation but is still than the normal function,indicate that the recovery of RV diastolic function is slower than systolic function.4.LV global function is impaired and systolic function is still in the lower line of normal value before operation in TOF.Compare with preoperation,the LV capacity at 12 d and 3 mon after operation increase obviously.LV systolic function doesn't improve,and LV diastolic function increase and global function improve at 12 d after operation.LV systolic function at 3 mon after operation raise to normal level,and LV global function improve to nearly normal level,imply that the recovery of LV systolic function is slower than diastolic function.5.TDI-Tei index can make estimation more accurate than C-Tei index to RV global function of TOF,and the same as C-Tei index to LV global function of TOF.6.Pulmonary artery branch regurgitation is valuable in diagnosis of pulmonary artery hypertension about the TOF patients after operation.