The Value Of MRI In Early Detection Of Right Ventricular Dysfunction After Postoperative Radical Surgery In Tetralogy Of Fallot

Objectives: Tetralogy of Fallot is one of the most common cyanotic congenital heart diseases,As tetralogy of Fallot often associated with severe right ventricular outflow tract stenosis and pulmonary valve dysplasia,it showed significant hypoxia symptoms after birth,and need radical surgery as early as possible.Long-term follow-up found that some children with pulmonary valve regurgitation increased.Long-term severe pulmonary valve regurgitation will lead to decompensation of the right ventricular volume overload,resulting in right ventricular dysfunction,the progress of irreversible right ventricular system failure,or even sudden death.Currently,the evaluation?Grade and stage of postoperative right ventricular function was evaluated by echocardiography.The accuracy of echocardiography on the evaluation of right ventricular function Parameter were all affected by the factors such as the subjective factors and the variability of right ventricular structure.Early detection of right ventricular dysfunction can discovery and treat the severe complications of Tetralogy of Fallot radical surgery,which is the top priority,and also an important research topic.Cardiovascular magnetic resonance imaging(CMRI)is a nonradiative imaging method with high resolution,high tissue contrast and a variety of parameters can be compared.In recent years it has been widely used to the diagnosis of cardiovascular disease.uploaded the image to AW4.3 can automatically measure the heart anatomy and physiological parameters,quantify the right ventricular structure and function,and the results of objective reality,repeatability,subject to subjective factors.In this study,CMRI was used to measure the ratio of right ventricular ejection fraction?pulmonary valve fraction,Especially for the first time use the ratio of right ventricular myocardium mass and right ventricularend-diastolic volume after radical surgery of TOF,which response of the early change of myocardial cell structure and function,To investigate the significance of the the ratio of right ventricular myocardium mass and right ventricular end-diastolic volume on the diagnosis of early right ventricular dysfunction after radical surgery of TOF.Methots:A total of 42 children underwent Tetralogy of Fallot radical correction surgery were enrolled in the Department of Cardiac Surgery Hebei Provincial Children's Hospital,Hebei Medical University,The patients were informed performing CMRI test.all cases of preoperative age form3 to 12 months,an average of 6.4 ± 1.6 months,according to the determination of diastolic reverse blood flow semi-quantitative show a small amount to medium amount of pulmonary valve regurgitation,and no residual shunt and residual obstruction occurred.according to the children's heart function classification standard(I:children with physical activity is not restricted;II: heavier labor has symptoms.III: light labor has the symptoms,activity was limited.IV:breathe difficult at resting state,hepatomegaly,complete loss of labor).There was no children cardiac function with grade IV.the fast imaging employing steady-state acquisition(FIESTA)was used to scan the macroscope and scan the field of vision 400 mm.Repeat time(TR)27 ms,callback time(TE)3.2ms,matrix 240x256,layer thickness 5 mm,Layer interval of 0.5mm.Children with nuclear magnetic resonance examination using a calm breath,children of incompatibility should be given10% chloral hydrate 0.5ml/kg oral or enema,given intravenous contrast agent gluco benzoic acid glucosamine salt(Gd-DTPA)0.2ml/kg,fast steady state preoperative imaging sequence(FIESTA)collection of quantitative ventricular volume and quality images,while adding parallel acquisition(i PAT)technology to reduce the imaging time and artifact generation.Vertical ventricular septum images were collected perpendicularly to the atrioventricular valve,and ventricular short axis images were collectedparallel to the atrioventricular valve.The acquired images were reconstructed by image,and the end systolic and end diastolic images were marked.1.Determination of right ventricular function,right ventricular end systolic volume(RVESV)and right ventricular end diastolic volume(RVEDV),the results by body surface area(BSA)correction calculation,right ventricular end systolic volume index(RVESVI),namely RVESVI=RVESV/BSA,calculate right ventricular end diastolic volume index(RVEDVI),namely RVEDVI=RVEDVI/BSA,calculate right ventricular ejection fraction(RVEF),namely(RVEF)=(RVEDV)-(RVESV)/(RVEDV* 100%.)by using spss19.0 statistical software to process data,the definition of RVEF<50% for heart failure and the single factor analysis of variance analysis,the critical value of statistically significant differences for P<0.05,three groups were compared the measured statistical differences of RVEF,RVESVI,RVEDVI,the result of the statistical was P<0.05,that the difference was statistically significant.2.Measurement of pulmonary valve regurgitation fraction: Pulmonary arterial blood flow correlation data were collected by phase contrast technique.Pulmonary arterial profile was determined in the sagittal long axis of the right ventricular outflow tract,fast film imaging sequence was used and in the direction of blood flow,the blood flow velocity was applied to encode the gradient field to obtain a series of phase diagrams of the blood flow information of the pulmonary valve level.The AW4.3 workstation automatically processed and analyzed the image data automatically,calculated the pulmonary valve Average Forward Flow(AFF)and Average Backward Flow(ANF),and then calculated the pulmonary regurgitation fraction(PRF=ANF/AFF*100%.),the result of the statistical was P<0.05,that the difference was statistically significant.3.The determination of the ratio of right ventricle myocardial mass right ventricle / right ventricular end diastolic volume according to the FIESTA sequence image manual depicting right ventricular epicardial and endocardial,septal,papillary cords and muscle trabecula and so on,which is not includedin the right ventricular mass,the calculation of right heart myocardial mass/volume ventricular ratio,RVMM/RVEDV,the results corrected by body surface area.Statistical analysis:Statistical analyses were analyzed by SPSS 19.0 statistical software.softwarethe,ONE-WAY ANOVA was used to compare demographic characteristics among right ventricular function parameters,PRF and RVMM/RVEDV.P value of less than 0.05 was considered indicative of a statistically significant Descriptive statistical Bonferroni method was used for comparison between groups,P value of less than 0.05 was considered indicative of a statistically significant Descriptive statistical.According to the RVEF values measured by CMRI,RVEF<40% was defined right ventricular dysfunction,analyzed the preoperative variables by K-S test for data distribution analysis,the Students t test and were reported as mean and standard between groups,Chi-squared test was used to compare between groups,Univariate and multivariate logistic regression models were used to identify factors independently associated with the presence of clinically relevant,Pearson correlation analysis were used to identify the variables.P value of less than 0.05 was considered indicative of a statistically significant Descriptive statistical.Results:1.Determination of right ventricular function by CMRI: children were divided into 3 groups by heart function classification standard,the measurement of the RVEF of the 3 group of children were RVEF = 60.4 +7.3%,55.3 + 10.7%,45.2 + 12.5%.RVEDVI were 35.7 + 11.6,37.3 + 5.3,55.5+ 6.4;RVESVI were 24.8 + 1.6,26.4 + 0.4,27.6 + 0.3;RVESVI was no statistically significant difference between the three groups(P>0.05),RVEDVI?RVEF showed a significant difference in the three groups(P<0.05),Bonferroni was used to compare the difference between groups,RVEF,RVEDVI were no statistical significance between group II and group I,and were statistical significance with group III.Moreover the measurement of thevalue of RVMM /RVEDV were 0.83 + 0.16,0.67 + 0.15,0.57 + 0.23,there were a significant difference between three groups.(P<0.05)(Table 1)2.Determination of PRF by CMRI: the determination of the PRF of the three groups were 23.5±10.2%,30.3±6.7%,38.2±8.3%,the difference was statistically significant(P<0.05).Each group were statistically significant difference,logistic regression analysis showed: PRF was a independent factors for reduction of the RVEF,Pearson analysis showed PRF and RVEF were negatively correlated.(r=-0.425 P =0.043)3.Children with RVEF<40%was defined right ventricular dysfunction,retrospective analysis of preoperative variables with single factor analysis found that the difference of aorta occlusion time,Mcgoon Ratio,ICU monitoring time,PRF RVEDVI RVMM/RVEDV were statistically significant,Logistic,regression,analysis,revealed,PRF,RVEDVI,RVMM/RVE DVI was the risk factors of right ventricular dysfunction,RVEDVI was negatively correlated with RVEF by Pearson correlation analysis(r=-0.788,P=0.001),while RVMM/RVEDV showed that RVEF were highly positive correlation.(r=0.869,P=0.001)Conclusions:1.CMRI showed that all of children with TOF had pulmonary regurgitation and heart function,the value of RVEF,RVEDVI were no significant difference in group I and group II,but had significant difference with group III,indicated the occurrence of cardiac insufficiency,the increase of RVEDVI the decreased of RVEF,While the myocardial was already expansionary change.There were statistically significant differences in RVMM/RVEDV in the early stage of cardiac functional insufficiency.When RVEF,RVEDVI did not change,RVMM/RVEDV had significance for the early diagnosis of right cardiac functional insufficiency.2.RVEF<40% is defined as right heart insufficiency,a retrospective analysis of the children's preoperative basic variables,Single factor variance analysis found that the aortic clamp time,Mcgoon ratio,ICU monitoring time,PRF,RVEDVI,RVMM/RVEDV were statistically significant,that childrenwith pulmonary vascular hypogenesis and the operation time,may have statistical significance with postoperative right ventricular dysfunction.3.PRF,RVEDVI,RVMM/RVEDV measured by CMRI were the risk factors of the reduction of RVEF.the measured value of PRF RVEDVI,RVMM/RVEDV had significantly correlated,with the reduction of RVEF.,the correlation coefficient of RVMM/RVEDV is closer to 1,was a sensitive index to evaluate right ventricular structure and function.at the early stage of Right ventricular myocardial volume decompensation.whitch indicate the early response of myocardial remodeling,interstitial fibrosis and other irreversible pathology For the early detection of right ventricular dysfunction is of great significance.