Application Of Three-dimensional Transesophageal Echocardiography In Preoperative Evaluation Of Transcatheter Aortic Valve Replacement

BackgroundTranscatheter aortic valve replacement(TAVR)has become one of the major methods in the treatment of moderate to severe aortic valve disease after development of more than ten years,its effectiveness and safety have already been widely recognized.The2017 AHA/ACC guidelines have recommended it as aⅠlevel treatment method for patients with severe aortic stenosis(AS)who are at high risk or inhibit for surgery,and studies on TAVR for patients with low risk are also underway.Direct vision is not available during TAVR process,and the performers cannot directly see or touch the anatomical structure of the surgical area.Accurate preoperative evaluation of the aortic root structure plays a crucial role in the decision of surgical strategies and the reduction of postoperative complications.Computed tomography(CT)is currently the golden standard resource for preoperative evaluation,but its use is often limited in specific populations such as renal insufficiency due to the exposure to ionizing radiation and the use of contrast agents.Three-dimensional transesophageal echocardiography(3D-TEE)is expected to be an alternative evaluation resource.Previous studies generally showed that the measurement results based on 3D-TEE are significantly lower than those based on CT.However,we found that the above mentioned studies generally have two shortcomings.Firstly,different measurement software and methods were used to evaluate 3D-TEE and CT data respectively,which may lead to systematic errors.Secondly,they were mainly concentrated on patients with severe AS.As more and more patients with pure aortic regurgitation(AR)had become candidates for TAVR,the representativeness of the above studies was insufficient.In addition,besides the inconsistencies of measurement software and methods,there is a lack of convincing research on whether there are other factors that may lead to the difference between 3D-TEE and CT results,and thus affect the accuracy of 3D-TEE measurement.ObjectiveUsing the same software and method to evaluate the aortic root structure of patients receiving TAVR in Xijing hospital for aortic valve disease(including AS and pure AR)based on preoperative 3D-TEE and CT data,respectively.Analysing the accuracy of3D-TEE in preoperative evaluation of TAVR compared with CT when the error led by inconsistent software and method has been eliminated and the representativeness of sample has been improved.In addition,we will also explore the influence of aortic root calcification on the accuracy of 3D-TEE in aortic annulus evaluations.MethodPart Ⅰ: we retrospectively studied the patients who underwent TAVR in the department of cardiovascular surgery in Xijing hospital from January 2016 to August 2019.Among them,45 patients whose 3D-TEE and CT data were well preserved and in the required format were included in the study.Mimics and multiplanar reconstruction method were used for evaluation based on 3D-TEE and CT.Annulus diameter-area derived(Da),annulus diameter-perimeter derived(Dp),annulus mean diameter,the left ventricular outflow tract(LVOT)diameter-Dp,the sinus tube junction(STJ)diameter-Dp and aortic sinus diameter were compared and analyzed.Part ⅱ: we retrospectively studied the patients who underwent TAVR in the department of cardiovascular surgery in Xijing hospital from January 2016 to August 2019.Among them,31 patients whose 3D-TEE and CT data were well preserved and in the required format were included in the study.The results of CT evaluation were regarded as golden standard,HU450 and HU850 were used as indicators to measure the severity of calcification,and spearman rank correlation and ROC(receiver operating characteristic,ROC)curve was used to analyze the correlation between aortic root calcification and accuracy of 3D-TEE in aortic annulus measurement.Result1.For the annulus and LVOT,the measurement results based on 3D-TEE were significantly lower than those of CT,and the correlation coefficient of the two groups was0.699 ～ 0.948(p < 0.01),indicating a relatively significant correlation.As for the STJ and aortic sinus,except for the STJ diameter-Dp in diastole(p=0.11),other results showed that,compared with CT,the measurement based on 3D-TEE would underestimated the size of each parameter(p < 0.01),and the correlation coefficient was 0.893 ～ 0.954,which also indicated a significant correlation between the two groups.2.Bland-Altman plot showed that the ordinate values were mostly within the 95% consistency limit,the consistency of the two groups was good.3.By establishing the linear regression equation,the two groups can be inferred from each other.Part ⅱ: Spearman rank correlation analysis: there was no statistically correlation between the degree of sinus calcification and the accuracy of 3D-TEE annulus evaluation(HU450: P = 0.183 ～ 0.992;HU-850: P = 0.414 ～ 0.829);ROC curve analysis: the area under the curve was 0.506 ± 0.110 ～ 0.688 ± 0.098(HU-450)and 0.512 ± 0.109 ～ 0.650± 0.101(HU850),respectively,indicating that the influence of sinus calcification on the accuracy of 3D-TEE annulus evaluation was limited.Conclusion1.After excluding the possible errors caused by the inconsistence of software and method and improving the sample representativeness,the evaluation based on 3D-TEE still significantly underestimated the results compared with the current golden standard CT evaluation.However,as the two groups obtain considerable correlation and consistency,we can deduce CT results from 3D-TEE results by establishing regression equation.For those who are contraindicated for CT,3D-TEE can be a good alternative.2.Calcification in the aortic sinus did not affect the accuracy of 3D-TEE annulus evaluation.