Intraoperative Transesophageal Echocardiography in the Evaluation of Residual Gradients after Surgical Correction of Right and Left Ventricular Outflow Tract Obstructions

Background: Despite the large use of intraoperative Transesophageal Echocardiography (TEE) in congenital heart surgery, limited information is available regarding ventricular outflow tract obstruction. Objective: The aim of this study was to assess the reliability of the post-bypass TEE to detect residual gradients in patients with ventricular outflow obstruction. Patients and Methods: Post-bypass TEE peak systolic gradients of 127 patients (mean age of 7 years), being 79 with right ventricular outflow tract obstruction and 48 with left ventricular outflow tract obstruction, were compared with the postoperative TTE. Postoperative lesions were considered of hemodynamic significance when peak systolic gradient was higher than 40 mmHg. Results: In patients with left ventricular outflow tract obstruction TEE showed mean peak systolic gradients higher than TTE (30 mmHg versus 24 mmHg; p= 0,014). In 75%, TEE gradients were lower than 40 mmHg and agreed with TTE in 97%. In the remaining patients, TEE gradients were higher than 40 mmHg and agree with TTE in 33%. In patients with right ventricular outflow tract obstruction TEE mean gradients agreed with TTE (28 mmHg versus 25 mmHg; p= 0.21). In 88%, TEE gradients were lower than 40 mmHg and agreed with TTE in 91.5%. In the remaining patients, TEE gradients were higher than 40 mmHg and agreed with TTE in 60%. Conclusion: TEE showed to be a reliable technique to detect residual ventricular outflow tract obstructions in the majority of patients. However, when considered gradients higher than 40 mmHg, TEE suggested a greater severity of obstructions, particularly on the left side (Arq Bras Cardiol: Imagem cardiovasc. 2014;27(4):229-234).