Inter-twin differences in fetal echocardiographic findings are associated with decreased dual twin survival in twin-twin transfusion syndrome.

To determine if inter-twin differences in fetal echocardiographic findings are associated with fetal survival in monochorionic pregnancies complicated by twin-to-twin transfusion syndrome (TTTS). This study included women who underwent laser surgery for TTTS between 2012 and 2018 at a single institution. Echocardiographic cardiac parameters in the donor and recipient twins were compared using Z-scores and regression analyses (adjusted for confounding variables) to determine whether any measurable inter-twin differences were associated with neonatal survival at birth. Results are expressed as (Odds ratio [95% confidence interval], p-value). Fetal echocardiography and delivery information was available in 124 TTTS cases. Dual live-birth occurred in 72% and at least one live-birth was seen in 89% of cases.Sixty-four percent (51/79) of recipient twins had evidence of cardiac dysfunction compared to 10% (8/79) of the donor twins (p < .01). In the logistic regression, inter-twin differences in left ventricle short axis dimension (0.62[0.44-0.87], p < .01), aortic valve diameter (0.67[0.45-0.99], p = .047), peak systolic velocity across the pulmonary artery (PA-PSV) (0.09[0.01-0.53], p < .01) and mitral valve diameter (0.56[0.38-0.84], p < .01) were associated with lower dual twin survival at birth. Inter-twin differences in left cardiac geometry and function are associated with decreased survival at delivery in TTTS.