Comparative Evaluation Of Left Atrial Appendage Parameters In Patients With Atrial Fibrillation By Transthoracic Echocardiography And Transesophageal Echocardiography

Objectives:To verify the feasibility of transthoracic echocardiography（TTE）in the structural and functional test of left atrial appendage（LAA）in patients with atrial fibrillation（AF）,to explore the clinical value of TTE in the evaluation of LAA in patients with AF and the feasibility of left atrial appendage opening transverse section to evaluate the structure of LAA,and to provides the possibility to evaluate LAA for patients located in primary hospitals without transesophageal echocardiography（TEE）and patients with contraindications for TEE.Methods:A total of 78 inpatients with AF who met the admission and exclusion criteria in the Cardiology Department were enrolled.Philips EPIQ7 C and Philips IE33 ultrasound machines were used to complete the TTE and TEE examinations by transthoracic S5-1 probe and the transesophageal X7-2 probe.The measurement of TTE data was completed by two physicians with more than ten years of work experience.The patient was placed in the left lateral position,and the left atrial appendage length（LAA-L）,left atrial appendage opening left and right diameter（LAA-OLR）,left atrial appendage peak emptying velocity（LAA-PEV）,left atrial appendage peak filling velocity（LAA-PFV）,left atrial appendage apex systolic tissue doppler imaging（LAAA-STDI）,left atrial appendage apex diastolic tissue doppler imaging（LAAA-DTDI）were measured in left atrial appendage long axis section,left atrial appendage opening long diameter（LAA-OLD）,left atrial appendage opening short diameter（LAA-OSD）,left atrial appendage opening maximum area(LAA-A_max),left atrial appendage opening minimum area(LAA-A_min)were measured in left atrial appendage opening transverse section.The measurement of TEE data was completed by a deputy senior professional doctor.Fasting and water-free for 8 to 10 hours before TEE,the patient took oral lidocaine for local anesthesia,connected ECG and took a supine,mouthpiece was placed in the mouth,and the probe penetrated the esophagus about 25 to 35 cm from the incisors.Stored the LAA two-dimensional image for analysis,then started 3D ZOOM and made two perpendicular two-dimensional images completely including the LAA target area,started 3D ZOOM again to obtain the three-dimensional image of LAA,and accessed the three-dimensional dynamic image.Qlab analysis software was used to measure the same parameters mentioned above.All data were averaged after three measurements.The statistical software SPSS 22.0 and Med Calc 15.2.2 were used to analyze the data.The Kolmogorov-Smirnov method was used to evaluate the distribution characteristics of the variables.If the quantitative data conformed to the normal distribution,it was described as （?）±s.If the quantitative data conformed to the skewed distribution,it was described as M（QR）.The consistency of the measured values between different observers used Bland-Altman analysis;the difference analysis between the two TTE and TEE used paired samples t test or Wilcoxon signed-rank test.The difference was statistically significant with P<0.05.Results:1 The analysis by the Kolmogorov-Smirnov method showed that all measured data and related differences conformed to the normal distribution.2 The consistency analysis of LAA parameters measured by TTE between different observers:95%CI of limits of agreement LAA-L,LAA-OLR,LAA-OLD,LAA-OSD,LAA-A_max,LAA-A_min,LAA-PEV,LAA-PFV,LAAA-STDI,LAAA-DTDI were（-0.5628,0.5936）mm,（-0.4237,0.3775）mm,（-0.6822,0.6180）mm,（-0.7967,0.7019）mm,（-0.3442,0.3390）cm²,（-0.4388,0.3824）cm²,（-0.4866,0.4096）cm/s,（-0.4766,0.3818）cm/s,（-0.4388,0.3824）cm/s,（-0.4177,0.3793）cm/s,and all the above parameters had more than 95% points within 95% limits of agreement.3 The correlation analysis results of related parameters measured by TTE and TEE:（1）structural parameters: the parameters of left atrial appendage long axis section: the correlation coefficients of LAA-L and LAA-OLR were 0.941,0.901,all have correlations（all P <0.05）.The parameters of left atrial appendage opening transverse section: the correlation coefficients of LAA-OLD,LAA-OSD,LAA-A_max,LAA-A_min were 0.985,0.954,0.727,0.707,all have correlations（all P <0.05）.（2）functional parameters: the correlation coefficients of LAA-PEV,LAA-PFV,LAAA-STDI,LAAA-DTDI were 0.996,0.991,0.966 and 0.889,all have correlations（all P <0.05）.4 The difference analysis results of related parameters measured by TTE and TEE:（1）structural parameters: the parameters of left atrial appendage long axis section: LAA-L and LAA-OLR were significantly different（all P < 0.05）.The parameters of left atrial appendage opening transverse section: LAA-OLD,LAA-OSD,LAA-A_max,LAA-A_min were no significantly different（all P > 0.05）.（2）functional parameters: there was no statistically significant difference in LAA-PEV,LAA-PFV,LAAA-STDI,LAAA-DTDI（all P > 0.05）.5 The consistency analysis of related parameters measured by TTE and TEE:95%CI of limits of agreement of LAA-L,LAA-OLR measured by left atrial appendage long axis section,LAA-OLD,LAA-OSD,LAA-A_max,LAA-A_min measured by left atrial appendage opening transverse section,the functional parameters of LAA-PEV,LAA-PFV,LAAA-STDI,LAAA-DTDI were（-1.859,2.351）mm,（-2.227,2.829）mm,（-1.032,1.234）mm,（-1.422,1.268）mm,（-1.125,1.145）cm²（-1.003,0.937）cm²,（-2.182,2.200）cm/s,（-2.888,2.690）cm/s,（-2.198,1.762）cm/s,（-2.590,2.224）cm/s,and all the above parameters had more than 95% points within 95% limits of agreement.Conclusions:1 When using TTE to measure LAA,the consistency between different observers is good,which proves that the evaluation of LAA by TEE is repeatable.2 TTE and TEE are not significantly different in evaluating LAA functional parameters,and have good correlation and consistency.TTE and TEE are significantly different in evaluating some LAA structural parameters,but have good correlation and consistency.TTE can be used as a feasible method for the evaluation of LAA of patients located in primary hospitals and patients with contraindications for TEE,but we still need to increase the sample size of the study.3 There is no statistically significant difference between the parameters of left atrial appendage measured by the left atrial appendage opening transverse section of TTE and the corresponding parameters measured by TEE,and the correlation and consistency are good.It provides the possibility to popularize the left atrial appendage opening transverse section of TTE to evaluate LAA,and we still need to increase the sample size and introduce more relevant parameters.