Effect of Tadalafil on Heart Function in Children with Severe Pulmonary Regurgitation Following Surgical Repair of Tetralogy of Fallot: A Prospective Study

Background: Tetralogy of Fallot (TOF) is the most prevalent cyanotic congenital heart defect. Pulmonary regurgitation (PR) is a common sequela following most surgical repairs for TOF. Tadalafil might reduce pulmonary vascular resistance after Tetralogy of Fallot total correction (TOFTC). Objectives: This study evaluated the efficacy of tadalafil in reducing PR volume and improving heart function among TOFTC children with severe PR, using transthoracic echocardiography, particularly focusing on changes in N-terminal pro-b-type Methods: The present study was conducted on TOFTC patients consecutively between September 2019 and August 2020 at Shiraz University of Medical Sciences, Shiraz, Iran. M-mode and two-dimensional (2D) Doppler echocardiography were performed, and NT-proBNP levels were measured in 20 patients before and one month after tadalafil administration. SPSS version 23.0 was utilized to analyze all results. Results: The patients' ages ranged from 25 to 128 months. The mean age and weight of the patients were 67.9 +/- 34.5 months and 21.1 +/- 6.9 kg, respectively. Tadalafil administration did not significantly improve Doppler and tissue Doppler parameters; however, it increased the pulmonary valve pressure gradient and velocity-time integral. Additionally, tadalafil had no significant effect on improving NT-proBNP levels. The Spearman correlation test did not show any significant correlation between the pulmonary valve pressure gradient and velocity-time integral with age, weight, and NT-proBNP. Conclusions: Tadalafil increased the pulmonary valve pressure gradient and velocity-time integral in TOFTC patients with severe PR; however, it did not affect NT-proBNP levels or tissue Doppler parameters.