A Case of Refractory Hypoxemia Caused by Anterior Leaflet Cleft of the Tricuspid Valve in a Neonate: A Case Report and Literature ReviewYang Meilin, Song Wenjing, Zhou Wenli Department of Neonatology, The First Hospital of Jilin University, Jilin 130021, China

Objective To investigate the clinical characteristics, imaging manifestations, and therapeutic strategies of refractory hypoxemia caused by anterior leaflet cleft of the tricuspid valve in neonates, in order to improve early recognition and management of this rare condition. Methods We retrospectively analyzed the clinical data of a neonate admitted to the Department of Neonatology, The First Hospital of Jilin University, in June 2024, who was diagnosed with anterior tricuspid leaflet cleft accompanied by severe pulmonary hypertension and refractory hypoxemia. Literature was retrieved from CNKI, Wanfang Database, Chinese Journal Full-text Database, PubMed, and Web of Science from database inception to October 2025 using the keywords “newborn,” “tricuspid valve cleft,” “tricuspid valve,” “chordae tendineae rupture,” “papillary muscle rupture,” “tricuspid valve,” “papillary muscle,” “chordae tendineae,” “rupture,” and “neonate.” Reported cases were reviewed to summarize clinical features, treatment approaches, and outcomes. Results The present case involved a term female infant (gestational age 38⁵/₇ weeks) who was admitted 4 hours after birth due to cyanosis. The infant, delivered via elective cesarean section, developed severe cyanosis and refractory hypoxemia immediately after birth. She showed poor response to standard treatment for pulmonary hypertension. After comprehensive management including fluid optimization, prostaglandin E₁ to maintain ductus arteriosus patency, and vasoactive agents, the patient’s condition improved. On day 4 after admission, echocardiography confirmed a 3.2 mm cleft at the junction between the anterior tricuspid leaflet and chordae tendineae. The infant did not undergo surgery, and cardiac function remained normal during follow-up after discharge. A total of 28 cases (including the present one) were identified through literature review: 27 term infants and 1 preterm infant. Thirteen had a definite history of perinatal asphyxia, and 26 presented with respiratory distress and cyanosis after birth. Twenty-two cases underwent surgical repair between 20 hours and 29 days after birth. Six cases (including the present one) did not undergo surgery; among them, three died (autopsy confirmed chordae tendineae rupture), while the remaining three (including the present case) survived with normal cardiac function during short-term follow-up. Conclusion Severe tricuspid regurgitation due to anterior tricuspid leaflet cleft is a rare but important cause of refractory hypoxemia in neonates. Its clinical presentation can be easily masked by pulmonary hypertension. Early recognition, precise hemodynamic management, and timely surgical intervention are essential to improving outcomes.