Prognostic value of echocardiographic parameters in congenital diaphragmatic hernia: a systematic review and meta-analysis

Background: Prognostication of mortality and decision to offer extracorporeal membrane oxygenation (ECMO) treatment in infants with congenital diaphragmatic hernia (CDH) can inform clinical management.

Objective: To summarise the prognostic value of echocardiography in infants with CDH.

Methods: Electronic databases Ovid MEDLINE, Embase, Scopus, CINAHL, the Cochrane Library and conference proceedings up to July 2022 were searched. Studies evaluating the prognostic performance of echocardiographic parameters in newborn infants were included. Risk of bias and applicability were assessed using the Quality Assessment of Prognostic Studies tool. We used a random-effect model for meta-analysis to compute mean differences (MDs) for continuous outcomes and relative risk (RR) for binary outcomes with 95% CIs. Our primary outcome was mortality; secondary outcomes were need for ECMO, duration of ventilation, length of stay, and need for oxygen and/or inhaled nitric oxide.

Results: Twenty-six studies were included that were of acceptable methodological quality. Increased diameters of the right and left pulmonary arteries at birth (mm), MD 0.95 (95% CI 0.45 and 1.46) and MD 0.79 (95% CI 0.58 to 0.99), respectively) were associated with survival. Left ventricular (LV) dysfunction, RR 2.40, (95% CI 1.98 to 2.91), right ventricular (RV) dysfunction, RR 1.83 (95% CI 1.29 to 2.60) and severe pulmonary hypertension (PH), RR 1.69, (95% CI 1.53 to 1.86) were associated with mortality. Left and RV dysfunctions, RR 3.30 (95% CI 2.19 to 4.98) and RR 2.16 (95% CI 1.85 to 2.52), respectively, significantly predicted decision to offer ECMO treatment. Limitations are lack of consensus on what parameter is optimal and standardisation of echo assessments.

Conclusions: LV and RV dysfunctions, PH and pulmonary artery diameter are useful prognostic factors among patients with CDH.