The Relationship of Pulmonary Artery Pressure and Survival in Congenital Diaphragmatic Hernia

Background/purpose: Pulmonary hypertension is an integral part of the pathophysiology of the respiratory failure associated with congenital diaphragmatic hernia. Hypothesizing that the evolution of the pulmonary hypertension would determine clinical outcome, the authors examined pulmonary artery pressures in relation to survival in their CDH patients.

Methods: The authors performed a retrospective chart review of all neonates with the CDH from 1991 to 2002 at their institution eliminating infants with complex congenital heart disease, prematurity, or limited treatment. Cardiac ECHO data were used to estimate pulmonary artery pressures as a ratio to systemic pressure. Statistical analyses of estimated pulmonary pressure ratios stratified by survival status and time were performed using chi2 and Fisher's Exact Test methods.

Results: Forty-seven full-term CDH infants with 428 cardiac ECHO evaluations were studied. Long-term survival rate was 74%. Forty-nine percent of patients had normal pulmonary artery pressure estimates within the first 3 weeks of life. All patients survived. Seventeen percent had persistent systemic or suprasystemic pressure estimates unrelieved by treatment interventions resulting in 100% mortality rate. Thirty-four percent had intermediate reductions in pressure estimates over time with 75% survival rate. Systemic pulmonary artery pressures were associated with decreased survival at all time-points when compared with normal-pressure survivors: week 1, 60% (P <.003); week 3, 38% (P <.007); week 6, 0% (P <.02).

Conclusions: The evolution of pulmonary hypertension is a critical determinant of survival in CDH patients with current treatment strategies. Three groups can be modeled with markedly different clinical performance patterns. Using serial cardiac ECHO examinations, pulmonary artery pressure estimations can be used to predict clinical outcome.