The Clinical Significance of Non-Ebsteinoid Fetal Tricuspid Valve Regurgitation.

Background: Tricuspid regurgitation (TR) is commonly identified via fetal echocardiography (FE). The association of TR in the fetal heart with neonatal outcomes remains poorly understood. We aimed to assess the spectrum and evolution of non-Ebsteinoid TR in fetuses and to understand the associated clinical outcomes in the current era.

Methods: We conducted a retrospective cohort study of all fetuses diagnosed with non-Ebsteinoid TR at a single center from January 1, 2012, to October 1, 2023. Eligible fetuses were divided into 3 groups based on the severity of TR on initial FE: mild, moderate, and severe. Initial and serial FE were reviewed along with postnatal echocardiographic findings. Prenatal variables and neonatal outcomes were also collected.

Results: A total of 67 fetuses met the inclusion criteria. Based on initial FE, 49 (73.1%) fetuses had mild TR, 15 (22.4%) had moderate TR, and 3 (4.5%) had severe TR, diagnosed at a median gestational age of 26.3 weeks [23.4, 32.3]. Of fetuses with mild TR that had worsening TR in utero (17.9%) or postnatally (17.6%), all had tricuspid valve (TV) dysplasia or right ventricle (RV) dysfunction noted prenatally. Compared to fetuses with mild TR and normal TV anatomy, fetuses with mild TR and TV dysplasia had larger TV annuli (1.12 cm vs 0.96 cm; P = .035) and RV internal diameter in diastole (1.59 cm vs 1.26 cm; P = .01). Newborns with prenatally diagnosed severe TR were more likely to require cardiac intensive care after birth (3/3 = 100%; P < .001) than those with mild (1/49 = 2%) or moderate TR (1/15 = 6.7%).

Conclusions: In the absence of TV dysplasia or RV dysfunction, mild, non-Ebsteinoid fetal TR can be considered a benign finding in the current era. However, when these findings are present, or in the patient with limited imaging windows, postnatal evaluation should be performed to rule out other primary cardiac disease.