Desaturation after Fontan procedure due to systemic venous collateral and improvement after closure with embolization.

Key Clinical Message: Systemic to pulmonary venous collaterals (SPVCs) are common findings in patients with Fontan and may be responsible for desaturation in this group of patients. In selected cases, percutaneous closure of SPVCs with coils or vascular plugs could be offered as a safe and effective treatment modality for these patients.

Abstract: A 27-year-old female patient who had operated primarily with Glenn operation and she underwent later a lateral tunnel Fontan operation. After 5 years, she presented with desaturation due to significant systemic to pulmonary venous collateral development, and a decision was made to proceed with interventional occlusion. Afterward, the arterial saturations increased.