The right ventricular systolic to diastolic duration ratio: A simple prognostic marker in congenital diaphragmatic hernia?

Aims: (i) To compare the ratio of right ventricular systolic to diastolic duration (SD/DD) in infants with congenital diaphragmatic hernia (CDH) and normal controls and (ii) to examine its association, if any, with outcomes in CDH. Methods: Retrospective chart and echocardiographic review of consecutive neonates (<1 month old) with CDH and term controls without structural heart defects. Right ventricular SD/DD was calculated by a single reader. Results: Infants with CDH (n = 29) were comparable to controls (n = 27) in their mean (SD) age [2.2 (3.3) vs. 2 (4.0) days], birthweight [3 (0.67) vs. 3 (0.69) kg] and proportion of males (48.2% vs. 72.4%). The DD and SD/DD were significantly abnormal in the CDH group, compared to controls. Among infants with CDH, those who died (n = 15) and those who died or required ECMO (n = 17) had significantly shorter DD and higher SD/DD ratio. At a cut-off of 1.3, SD/DD ratio had a sensitivity of 92.8 (95% CI 64-99%) and specificity of 61.5 (32-85%) for prediction of mortality. Significant independent associations with mortality were observed with antenatal diagnosis (p = 0.003) and higher SD/DD ratio (p = 0.04). Conclusion: The right ventricular SD/DD ratio is a sensitive objective prognostic marker in infants with CDH. Further studies incorporating SD/DD ratio as a guide to intervention are warranted.