A Study On The Value Of Four-dimensional Transesophageal Echocardiography In Mitral Valvuloplasty

Background Mitral regurgitation(MR)is the most common heart valve disease clinically.The classic surgical treatment is mitral valve replacement(MVR).However,with the deepening understanding of mitral valve structure,mitral valvuloplasty(MVP)has gradually replaced MVR as the preferred surgical treatment for mitral regurgitation.In the early stage of MVP,transthoracic echocardiography(TTE)and two-dimensional transesophageal echocardiography(2D-TEE)were used to diagnose the lesions before operation,and then a general strategy was formulated according to the results of ultrasonic examination.However,the diagnosis of these two-dimensional plane images depend on the experience of the ultrasound doctors,and the clinical parameters available to the surgeon are limited.Four-dimensional transesophageal echocardiography(4D-TEE)technology can real-time,accurately presents the spatial structure of mitral valve,through the model similar to the surgical field intuitively showing the morphology of the mitral valve leaflet with the lesion during mitral regurgitation,reduce the interpretation of two-dimensional images by ultrasound doctors and the reconstruction steps of the interpretation by surgeons,so as to assist the formulation of surgical plan more effectively.Objective To explore the application value of four-dimensional transesophageal echocardiography(4D-TEE)in mitral valvuloplasty(MVP).Methods Retrospective analysis was performed on the clinical data of 59 patients who were admitted to the Department of Cardiac and Grand Vascular Surgery of the First Affiliated Hospital of Anhui Medical University from February 2019 to January 2020and were scheduled to undergo MVP due to mitral regurgitation(MR),including 39males and 20 females,aged(55.31±10.85)years.All patients underwent transthoracic echocardiography(TTE)in the outpatient department,and left atrium anterior-posterior diameter(LAD),left ventricular end diastolic diameter(LVEDD),left ventricular ejection fraction(LVEF),the area of mitral regurgitation and the area of left atrium were measured at the same time.Then all patients underwent 4D-TEE examination before MVP.The cause of mitral regurgitation,lesion type,lesion location,and the degree of regurgitation was accurately evaluated.And the intertrigonal distance,anterolateral to posteromedial diameter(DAl Pm)of systolic mitral annulus,anterior to posterior diameter(DAP)of systolic mitral annulus,and the length of the outer,middle and inner position of the anterior and posterior leaflet of the mitral valve which was named as A1～A3 and P1～P3 were measured respectively.Then,on the basis of the test results,a surgical plan was worked out.Intraoperative exploration verified the preoperative ultrasonic detection results,and selected the appropriate forming ring size.After the MVP operation,we directly measured the coaptation height of the mitral valve leaflet with methylene blue staining.TEE was performed again after cardiac resuscitation.The coaptation height of the mitral valve leaflet was measured and the surgical effect was evaluated immediately.MVP was successfully performed in 55 of 59patients.The 55 patients were followed up one year after surgery,and TTE was examined again,LAD,LVEDD,LVEF,the area of mitral regurgitation and the area of left atrium were measured meanwhile.(1)Observe the cause of mitral regurgitation,lesion type,lesion location and degree of regurgitation diagnosed by 4D-TEE before surgery,and the consistency with the intraoperative exploration results.(2)Compare the changes of parameters measured by TTE in the preoperative outpatient department and the one year follow-up after operation.(3)The correlation between parameters of the mitral valve obtained by 4d-TEE before surgery and the final size of the forming ring used during surgery was compared.(4)To compare the correlation between the coaptation height measured by 4D-TEE after cardiac resuscitation and the coaptation height measured by methylene blue staining under direct vision by the operator.(5)Analyze the influencing factors of the degree of mitral regurgitation one year postoperatively.Results The accuracy of etiology and lesion type in 59 patients was 96.6%(57/59)compared with the results of preoperative 4D-TEE and intraoperative exploration.The accuracy of diagnosis for a single region of the mitral valve leaflet was 31/31,and the accuracy of diagnosis for combined lesions in two regions and complex lesions in multiple regions was 13/15 and 6/8,respectively.Preoperative 4D-TEE evaluation of mitral regurgitation degree in 10 cases of grade 3,and 49 cases of grade 4 were consistent with the results of intraoperative exploration.The parameters measured by TTE during preoperative and postoperative one year follow-up were compared,LAD,LVEDD,the area of mitral regurgitation and the area of left atrium were statistically significant(All P values were<0.001),and LVEF was not statistically significant(P value>0.05).The stepwise multiple linear regression analysis of the intraoperative forming ring size with each index measured by preoperative 4D-TEE showed that DAP(X1)and the intertrigonal distance(X2)were entered into the regression model.The multivariate linear equation the size of the forming ring Y=10.380+0.243X1+0.387X2was established and the model was statistically significant(P value<0.001),and the R~2value of the determination coefficient was 0.532,indicating that the model fitting effect was good.The standardized partial regression coefficient of DAP is 0.485,and the standardized partial regression coefficient of the intertrigonal distance is 0.350,suggesting that both of them were of great significance for the prediction of the forming ring size.Pearson correlation analysis was conducted between the coaptation height of A1-P1,A2-P2,A3-P3 and the average coaptation height of the 3 coaptation edges and the coaptation height measured under the direct view of methylene blue staining during the operation.Correlation coefficients of the four groups were 0.618,0.879,0.562 and0.810,respectively,which were positively correlated(All P values were<0.01).The factors influencing the degree of mitral regurgitation one year after surgery were analyzed.Logistic regression analysis showed that the average coaptation height≤6.7mm was the risk factor of postoperative mitral regurgitation with an OR value of4.733(P=0.024),and suggesting that the patients whose average coaptation height was≤6.7mm were more likely to have recurrent regurgitation.Conclusion 4D-TEE can not only accurately determine the cause of mitral regurgitation,lesion type,lesion location and degree of regurgitation before mitral valvuloplasty,but also predict the actual size of the forming ring used in the operation according to the measured quantitative parameters,so as to assist surgeons in the decision of operation plan.Moreover,the efficacy of the operation can be evaluated in real time during the operation,which improves the success rate of the operation.In addition,the parameters provided by it have a certain predictive value for the early postoperative forming effect,so it has a very important clinical application prospect.