Progression of Truncal Valve regurgitation during fetal life: a retrospective multicenter study

Background Truncal valve regurgitation is a key factor impacting outcomes in patients with truncus arteriosus. Patients with moderate or greater regurgitation have elevated risk for early and late postoperative mortality. While the influence of regurgitation on postnatal outcomes is well-documented, its progression during fetal life is less understood. Our goal is to provide accurate prognostic information to parents by describing how truncal valve regurgitation evolves throughout pregnancy and whether this progression is related to cusp morphology, type of truncus arteriosus, or genetic abnormalities. Materials and Methods This retrospective multicenter study includes fetuses diagnosed with truncus arteriosus between January 2003 and April 2024. We analyzed the progression of truncal valve regurgitation by comparing first and second trimester fetal echocardiograms, as well as early postnatal echocardiograms. Regurgitation was assessed semi-quantitatively and classified as none, absent, moderate, or severe. The primary endpoint was to describe how truncal valve regurgitation progresses during fetal life and to assess whether it is associated with cusp number, truncus arteriosus type, or genetic abnormalities. Results Out of 56 initial fetal echocardiograms, 10 pregnancies were terminated, 4 cases were excluded due to moderate or severe regurgitation in the first trimester, 5 cases did not confirm a diagnosis of truncus arteriosus, and 4 were lost to follow-up. Comparing the second with the third trimester fetal echocardiogram, 2 patients progressed from absent/mild to moderate. When only third trimester echocardiogram was available, due to late referral, only 1 patient progressed from absent/mild to moderate regurgitation compared with postnatal assessment. Bicuspid and quadricuspid valves were more likely to exhibit progressive regurgitation (p = 0.049), while no significant association was found with genetic abnormalities or the type of truncus arteriosus. Conclusion Truncal valve regurgitation rarely progresses during fetal life and it is more likely to occur in cases with bicuspid or quadricuspid valves. These findings may be useful in counseling families with fetuses diagnosed with minimal truncal valve regurgitation, helping to set realistic expectations regarding postnatal outcomes. The counseling can be somewhat reassuring that the risk of progression to more significant truncal regurgitation is fairly low.