Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 3 1 2008 01 22 39 42 Seiied Mahmoud Meraji Shahid Rajaei Hospital, Iran University of Medical Sciences, Tehran, Iran. Paridokht Nokhostin Davari Shahid Rajaei Hospital, Iran University of Medical Sciences, Tehran, Iran. Mohammad Yousef Aarabi Shahid Rajaei Hospital, Iran University of Medical Sciences, Tehran, Iran. Ali Akbar Shahmohammadi Shahid Rajaei Hospital, Iran University of Medical Sciences, Tehran, Iran. Hojjat Mortezaeian Shahid Rajaei Hospital, Iran University of Medical Sciences, Tehran, Iran. Ramin Emamzadegan Shahid Rajaei Hospital, Iran University of Medical Sciences, Tehran, Iran. 2015 10 03 Background: Fenestration in the modified Fontan operation allows right-to-left shunting, which reduces the Fontan pathway pressure and improves cardiac output. However, on account of the fact that persistent right-to-left shunting results in cyanosis and paradoxical emboli, fenestration closure is recommended after recovery from the Fontan operation. Methods: This study recruited 3 patients who underwent the transcatheter closure of the Fontan fenestration with the ASD-Amplatzer because of severe cyanosis and significant intracardiac shunts. Results: Fenestration closure was performed at a mean age of 8 yr (6-12 yr) and average of 15 months after the Fontan operation. Aortic O2 saturation increased by an average of 17.6% (9-26%). During more than a two-year period of follow-up (mean: 27 months), two patients had complete occlusion on echocardiography and the other one had a small residual shunt. One of these patients had atrial flutter during the follow-up. Conclusion: The transcatheter closure of the Fontan fenestration is a safe and feasible technique that is effective in elevating systemic O2 saturation and well-being and confers acceptable growth and development in children. https://rhythm.tums.ac.ir/index.php/jthc/article/view/82 https://rhythm.tums.ac.ir/index.php/jthc/article/download/82/80