O1007: Comparison of Post-operative Transesophageal and Transthoracic Echocardiogram Findings Following Atrioventricular Septal Defect Repair

Background: Success of atrioventricular septal defect (AVSD) repair is defined by post-operative left and right atrioventricular valve (AVV) function and presence of residual intracardiac shunting. Intra-operative transesophageal echocardiography (TEE) provides critical information on repair quality. However, interpretation of AVV function and identification of residual lesions may differ systematically in TEE compared to pre-discharge transthoracic echocardiograms (TTEs) given different hemodynamic states and technical differences between modalities. We sought to evaluate assessment of AVV function and residual lesions on post-operative TEEs as compared to post-operative TTEs in a contemporary cohort of infants undergoing AVSD repair.

Methods: Patients 0-12 months old who underwent AVSD repair at our center from 2018 to 2022 were identified. Patients with unbalanced defects, left-sided obstructive lesions, or additional complex lesions were excluded. Clinical data were extracted from the medical record. A single cardiologist reviewed all TEE and post-operative TTE images and measured AVV inflow gradients on each study. Identification rate of residual lesions was compared between modalities; residual shunts were characterized as trivial/small, moderate, or large. Data were compared using standard univariate tests. A p-value of < 0.05 was considered significant.

Results: 106 patients were identified. Mean age and weight at time of operation were 160 ± 45 days and 5.34 ± 1.01 kg, respectively; 92/106 (86.8%) of patients had trisomy 21. Heart rates were similar for TEE and TTE, but blood pressure was increased at time of TTE. Left ventricular systolic function improved from TEE to TTE. There were no significant changes in left AVV inflow gradients between studies. However, the degree of left AVV regurgitation increased from TEE to TTE. The right AVV inflow gradients and regurgitation were both increased from TEE to TTE (Table 1). There were 30 patients in whom a residual ventricular septal defect (VSD) was seen on TTE that was not identified on TEE and 13 patients in whom an atrial septal defect (ASD) was identified on TTE but not TEE. All VSDs and ASDs identified only on post-operative TTE were trivial or small. Among patients with VSDs identified on both TEE and TTE, there were no patients in whom the defect by TTE was characterized in a larger size category than that assigned from TEE.

Conclusion: Both left and right AVV regurgitation increase on TTE assessment compared to TEE. The right AVV inflow gradient was increased on TTE relative to TEE. Although there are a significant number of patients with residual intracardiac shunts not visualized on TEE but discovered on TTE, these defects are hemodynamically insignificant. Knowledge of the expected changes in left and right AVV function from TEE to TTE can inform intra-operative decision-making, especially regarding decision to return to cardiopulmonary bypass to address residual lesions.