Supplementary Material for: Common arterial trunk in fetal life: accuracy of diagnosis and prediction of outcome

Introduction Common arterial trunk (CAT) is a congenital heart disease with significant perinatal mortality in which diagnostic agreement remains low. Methods Retrospective cohort study on fetuses with suspected CAT. Diagnostic accuracy was tested considering gold-standard postnatal ultrasound or necropsy. Prenatal sonographic markers were evaluated by logistic regression for perinatal survival. Results There were 79 fetuses with suspected CAT, and 55 cases had available necropsy/postnatal ultrasound conforming the study population. The diagnostic accuracy was 90.9% for CAT and 83.6% at a subtype level. In those with a confirmed diagnosis and intention-to-treat (n=28) composite early-mortality (intrauterine, pre-surgical and early-surgery) was of 25%, 10.5% in isolated-cases. The OR for early-mortality of isolated-cases was 0.13 [95% confidence interval (CI) 0.03-0.75]. After adjusting for isolated-cases, the only prognostic prenatal markers of perinatal mortality were a dysplastic truncal valve OR 7.78 (95% CI 1.23-49.13) and a stenotic flow OR 8.48 (95%CI 1.40-51.10) Conclusion CAT is a condition that if evaluated by experts, can be diagnosed with a high degree of accuracy. It remains an entity with high perinatal mortality. Its most important prognostic factor is its association with other anomalies. In isolated cases, the presence of a dysplastic truncal valve and a stenotic flow increase the chances of perinatal death.