Estimation of right ventricle to pulmonary artery pressure gradient in patients subjected to intracardiac repair for tetralogy of fallot – a comparison of echocardiographic methods vs direct pressure measurement

Background: The tetralogy of Fallot (TOF) is surgically corrected by Intra Cardiac Repair which involves the resection of muscle bundles that obstruct the right ventricular outflow tract (RVOT) thus increasing the pulmonary blood flow. The most common problem following corrective surgery is residual RVOT obstruction. The aim of the study is to assess whether TEE can provide reliable estimate of the RVOT gradients in patients with TOF. Methods -60 patients who were scheduled for Intra Cardiac Repair for TOF were included in the study after obtaining informed and written consent. Study design-Prospective observational study. During the preoperative&postoperative phase, the RV-PA gradient was obtained from the ME ascending aortic short axis view ,UE aortic arch short axis view and the TG RV outflow view and the gradients so obtained were compared with the preoperative RV – PA gradient obtained by the surgeon using a needle-saline filled pressure transducer system. Results-Appropriate statistical analysis of the results revealed the following significant findings: • TEE can provide reliable estimates of RVOT gradients in patients with TOF, especially in the post CPB period. • In the pre CPB period, the intraoperatively measured highest echocardiography gradients showed a relatively weak correlation (R=.216) when compared to the needle gradients. • In the post CPB period, relatively strong correlation (R=.657) was observed between the highest intraoperative echocardiography gradients and the needle gradients. All the individual TEE views had a clinical and statistical significant levels of correlation with the needle-saline-transducer gradient. Conclusion: The use of intraoperative TEE provides reliable estimates of the RVOT gradients in patients with TOF undergoing ICR in both pre and post CPB period. TEE can be recommended as a less invasive modality to measure the RVOT gradients with accuracy instead of the more invasive needle-saline-transducer gradient measurements.