Pulmonary artery diameter ratio as a prognostic indicator of congenital diaphragmatic hernia

Background Following on from an earlier study published in 2008 about left pulmonary artery (LPA) flow measured on serial echocardiography being strongly prognostic in left-sided congenital diaphragmatic hernia (CDH) and the ratio of LPA to right pulmonary artery (RPA) diameters being a simple and reliable indicator for commencing nitric oxide (NO) therapy, the ratio of LPA:RPA diameters (PA ratio or PAR) was hypothesized to possibly reflect cardiopulmonary stresses accompanying CDH better. Methods Subjects with isolated left-sided CDH treated between 2007 and 2020 at a single pediatric surgical center were recruited and classified according to survival. Data obtained retrospectively for subject demographics, clinical course, LPA/RPA diameters, and PAR were compared between survivors and non-survivors. The value of PAR for optimizing the prognostic value of PA diameter data in CDH were analyzed with receiver operating characteristic (ROC) curve analysis. Results Of 65 subjects, there were 54 survivors (82.3%) and 11 non-survivors (17.7%); 7 of 11 non-survivors died before surgical repair could be performed. Mean PAR for survivors (0.851±0.152) was significantly higher than for non-survivors (0.672±0.108) ( p =0.0003). Mean PAR for non-survivors was not affected by surgical repair. Characteristics of survivors were: LPA ≥2 mm (n=52 of 54; mean PAR=0.866±0.146) and RPA ≥3 mm (n=46 of 54; mean PAR=0.857±0.152). Non-survivors with similar LPA and RPA diameters to survivors had significantly lower mean PAR. ROC curve cut-off for PAR was 0.762. Subjects with high PAR (≥0.762) required high-frequency oscillatory ventilation/NO less than subjects with low PAR (<0.762) ( p =0.0244 and p =0.0485, respectively) and subjects with high PAR stabilized significantly earlier than subjects with low PAR (1.71±0.68 days vs 3.20±0.87 days) ( p <0.0001). Conclusions PAR would appear to be strongly correlated with clinical outcome in CDH and be useful for planning management of cardiopulmonary instability in CDH. Data are available upon reasonable request.