Clinical application value of intraoperative transesophageal echocardiography in pediatric cardiac valvular disease

Background: To explore the value of intraoperative transesophageal echocardiography (TEE) in the surgical treatment of pediatric cardiac valvular disease. Methods: Transthoracic echocardiography (TTE) was performed in 64 children with cardiac valvular disease, of which 49 patients underwent TEE before and after cardiopulmonary bypass. Results: The coincidence rate of preoperative TEE with the surgical diagnosis on valvular lesions was 100%, higher than that of TTE (78%). TEE supplemented or corrected 10 cases of TTE valvular lesion diagnosis, improving the accuracy of valvular disease diagnosis. Besides, TEE can effectively evaluate the surgical results. Conclusions: Preoperative TEE can accurately diagnose valvular disease in children, which helps to develop a surgical plan. Postoperative TEE can find the remaining problems in time and improve the success rate of surgery.


Background
Transesophageal echocardiography (TEE) examination has been widely used in coronary heart disease (CHD) and valvular disease surgery [1][2][3][4][5], showing important value for making treatment decisions. Before the advent of pediatric-specific TEE probes, we used transthoracic echocardiography (TTE) for children with heart disease. Compared with TTE, TEE has better sound-transparent conditions, especially for older children, obese children, and children with significant lung interference.
How to better use TEE to monitor the valve during the perioperative period is of great significance to improve the success rate of surgery and reduce complications. This study performed a TEE examination on patients and compared it with TTE to evaluate the value of TEE in the surgical treatment of children with cardiac valvular disease.

Methods
The present study was approved by the Ethics Committee of Department of ultrasound, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China. Written informed consent was obtained from all participants.

Patients
From January 2017 to March 2019, 64 children with valvular heart disease were enrolled, including 36 males and 28 females, aged from 1 month to 160 months, with an average of (40.3 ± 41.1) months. There were 36 cases of common atrioventricular canal with valvular disease, 9 cases of Ebstein's anomaly, 8 cases of ventricular septal defect, atrial septal defect and patent ductus arteriosus combined with valvular lesion, 1 case of coarctation of aortic arch with mitral valve disease, 1 case of pulmonary stenosis with tricuspid valve disease, 2 cases of mitral stenosis with insufficiency, 1 case of mitral valve prolapse with cleft, 2 cases of two lobe malformation of aortic valve, 1 case of aortic-left ventricular canal with aortic insufficiency, and 3 cases of valvular disease caused by infective endocarditis (Figure 1-10).
Transthoracic echocardiography (TTE) was performed in 64 children with cardiac valvular disease, of which 49 patients underwent transesophageal echocardiography (TEE) before and after cardiopulmonary bypass.
Inclusion criteria: patients with congenital or secondary heart valve disease; children with calm coordination, and clear ultrasound images can thus be obtained; patients with at least two times of transthoracic heart Doppler ultrasound; preoperative, intraoperative, and postoperative ultrasound examinations were completed by a doctor with more than 13 years of experience; cardiac function ejection fraction (EF) ≥ 55%; hospitalized patients with complete medical records; patients who can actively cooperate with the treatment and follow-up.
Exclusion criteria: patients with valvular regurgitation after heart surgery; patients with unexplained valvular regurgitation; patients who had not been diagnosed by surgical treatment; patients combined with fever, pneumonia (gas would affect the clarity of transthoracic ultrasound images when coughing), chest fluid, and pericardial effusion; cardiac function EF < 55%; patients without postoperative follow-up data.
Methods TTE was performed on 64 children undergoing surgical treatment with a Philips iE33 color ultrasound system, S8-3 probe, S5-1 probe, GE VividE9 color Doppler ultrasound, M5S probe, and 6S probe. During the examination, the child was placed in the supine position or the left lateral position. The uncooperative person was sedated with 10% chloral hydrate to fully expose the chest. The heart anatomy was routinely scanned to determine whether the heart was deformed, with the valve carefully observed.
During the operation, the Philips iE33 ultrasound system was applied. The S7-3t and S8-3t were inserted through the esophageal probe, and the area associated with heart disease in 49 patients with general anesthesia was examined and compared with preoperative TTE results. The examination information was communicated to the cardiac surgeon in time and compared with the intraoperative findings. After the operation, the heart was reexplored and TEE was used to evaluate the effect of the operation.

Comparison of preoperative TTE and TEE diagnosis results
There was no significant difference in baseline data between patients undergoing TTE and TEE (P > 0.05) ( Table 1). The coincidence rate of TTE and surgical diagnosis of 64 children was 78% (50/64) (Table 2), of which 49 patients receiving preoperative and postoperative TEE obtained satisfactory two-dimensional and color Doppler sonograms. Especially for valvular lesions, TEE had more advantages than TTE, clearly showing the shape, echo, opening, and closing of the leaflets, fissures, as well as other malformations in the heart, which were basically consistent with the findings during the operation. Ten patients (Table   3) were diagnosed or corrected by preoperative TEE examination, and the coincidence rate with the surgical diagnosis was 100% (49/49).
Accuracy of the diagnosis of the valvular disease improved by TEE TEE made a clear etiological diagnosis of valvular lesions diagnosed by preoperative TTE, including 10 cases of supplemental or modified diagnosis, consistent with surgical findings (Table 4).

Postoperative TEE assessment of surgical outcomes
Immediately after the operation, the TEE was evaluated, and 3 cases were found to have significant residual problems. The residual septal flow was greater than 2 mm, and the flow velocity was greater than 3 m/s in two cases; the valve was moderate insufficiency in one case. As the TEE was found timely, it was handled accordingly and the results were satisfactory.
The success rate of 49 cases of TEE probe insertion into the esophagus was 100%. All children were able to tolerate TEE and no adverse complications occurred. For children with cardiopulmonary bypass, ventilatory guidance in the left heart system was performed under the observation of TEE before the end of cardiopulmonary bypass, and air embolism complications did not occur in all children.

Discussion
The most common cause of valvular disease in children is congenital heart disease, followed by infective endocarditis and rheumatic valvular disease. In this group of 64 children, 61 cases were the congenital valvular disease, of which 36 cases (56.25%) were common atrioventricular canal with valvular disease, and 3 cases were caused by infective endocarditis.
The clinical application of TEE in pediatrics has greatly overcome the limitations of TTE and has become an important tool for the diagnosis of cardiac valvular disease in children. CONSENT FOR PUBLICATION All parents, guardians or next of kin provided written informed consent for the minors to participate in this study. Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.

AVAILABILITY OF DATA AND MATERIALS
The analyzed data sets generated during the study are available from the corresponding author on reasonable request.

COMPETING INTERESTS
The authors declare that they had no competing interests.       Ebstein's anomaly. A: Cuspis medialis valvulae tricuspidalis moves downward; B: The tricuspid valve is poorly developed and the tricuspid regurgitation is obvious.       Infective endocarditis with mitral valve posterior perforation.

Figure 10
Left coronary artery-right atrial fistula complicated with infective endocarditis. A: The neoplasm is visible in the fistula; B: The neoplasm continues to the right atrium, and it is also visible in the aortic valve.