UNGUARDED TRICUSPID VALVE FETAL ECHO

unguarded tricuspid valve (UTVO) in a fetus is a rare, severe congenital heart defect characterized by the partial or complete absence of leaflets, creating an “empty” atrioventricular ring. Fetal echocardiography typically shows massive right atrial and ventricle enlargement, severe tricuspid regurgitation, and a characteristic low-velocity “to-and-fro” flow pattern across the tricuspid orifice. 

Key Fetal Echocardiographic Findings:

• Absent Leaflets: Inability to visualize tricuspid valve leaflets (subvalvular apparatus) in the 4-chamber view.
• “Empty” Ring: The annulus appears “empty” or void of moving tissue.
• Severe Tricuspid Regurgitation: Color Doppler shows massive, often pan-systolic regurgitation (regurgitant flow) from the right ventricle into the right atrium.
• “To-and-Fro” Flow: Doppler spectrum across the valve shows a to-and-fro flow pattern.
• Chamber Enlargement: Gross dilation of the right atrium and right ventricle due to severe regurgitation.
• Associated Findings: Frequently associated with pulmonary atresia with intact ventricular septum (PA/IVS) (70% of cases), noncompacted myocardium, or ventricular dysfunction. 

Prognosis and Management:

• High Risk: Due to the severe nature of the defect, it often carries a poor prognosis, with cases of intrauterine death or early neonatal mortality.
• Diagnosis: Requires careful, detailed fetal echocardiography to distinguish it from Ebstein’s anomaly or dysplasia.
• Management: Some cases may be candidates for specialized, staged neonatal surgical intervention.