Valve-in-Valve Repair in a Critically Ill Obstetric Patient with Severe Pulmonary Stenosis: A Rare Case

<b>Background:</b> Among patients with congenital heart disease, particularly those with a history of undergoing the Fontan operation, pregnancy presents a significant maternal-fetal risk, especially when complicated by severe valvular dysfunction. Lung reperfusion syndrome (LRS) is a rare but life-threatening complication occurring following valve intervention. Multidisciplinary management, including by Cardio-Obstetrics teams, is essential for optimizing outcomes in such high-risk cases. <b>Methods</b>: We present the case of a 37-year-old pregnant patient with previously repaired tetralogy of Fallot (via the Fontan procedure) who presented at 24 weeks gestation with worsening severe pulmonary stenosis and right-ventricular dysfunction. The patient had been lost to cardiac follow-up for over a decade. She experienced recurrent arrhythmias, including supraventricular and non-sustained ventricular tachycardia, prompting hospital admission. A multidisciplinary team recommended transcatheter pulmonic valve replacement (TPVR), performed at 28 weeks' gestation. <b>Results</b>: Post-TPVR, the patient developed acute hypoxia and hypotension, consistent with Lung Reperfusion Syndrome, necessitating intensive cardiopulmonary support. Despite initial stabilization, progressive maternal respiratory failure and fetal compromise led to an emergent cesarean delivery. The neonate's neonatal intensive care unit (NICU) course was complicated by spontaneous intestinal perforation, while the mother required intensive care unit (ICU)-level care and a bronchoscopy due to new pulmonary findings. She was extubated and discharged in stable condition on postoperative day five. <b>Conclusions</b>: This case underscores the complexity of managing severe congenital heart disease and valve pathology during pregnancy. Lung reperfusion syndrome should be recognized as a potential complication following TPVR, particularly in pregnant patients with Fontan physiology. Early involvement of a multidisciplinary Cardio-Obstetrics team and structured peripartum planning are critical to improving both maternal and neonatal outcomes.