Right Ventricular Strain, Brain Natriuretic Peptide, and Mortality in Congenital Diaphragmatic Hernia

Abstract

Rationale: Brain-type natriuretic peptide (BNP) correlates with pulmonary hypertension as demonstrated by echocardiogram in congenital diaphragmatic hernia (CDH); however, its association with right ventricular (RV) function and mortality is unknown.Objectives: To characterize the relationships between echocardiogram-derived RV strain, BNP, and mortality in diaphragmatic hernia.Methods: We performed a single-center retrospective cohort study of infants with CDH and at least one BNP-echocardiogram pair within a 24-hour period. RV global longitudinal strain (GLS) and free-wall strain (FWS) were measured on existing echocardiograms. Associations among strain, BNP, and mortality were tested using mixed-effect linear and logistic regression models. Survival analysis was stratified by BNP and strain abnormalities.Results: There were 220 infants with 460 BNP-echocardiogram pairs obtained preoperatively (n = 237), ≤1 week postoperatively (n = 35), and >1 week postoperatively ("recovery"; n = 188). Strain improved after repair (P < 0.0001 for all periods). Higher BNP level was associated with worse strain in recovery but not before or immediately after operation (estimate [95% confidence interval] for recovery: GLS, 1.03 [0.50-1.57]; P = 0.0003; FWS, 0.62 [0.01-1.22]; P = 0.047). BNP and strain abnormalities were associated with an extracorporeal-membrane oxygenation requirement. Higher BNP level in recovery was associated with greater mortality (odds ratio, 11.2 [1.2-571.3]; P = 0.02). Abnormal strain in recovery had high sensitivity for detection of mortality (100% for GLS; 100% for FWS) but had low specificity for detection of mortality (28% for GLS; 48% for FWS).Conclusions: Persistent RV dysfunction after CDH repair may be detected by a high BNP level and abnormal RV strain.

Keywords: congenital diaphragmatic hernias; heart; pediatrics; pulmonary hypertension; ventricles.

Figure 1.

BNP decreases after congenital diaphragmatic hernia repair. The P value is for comparisons among the pre-op, immediate post-op, and recovery periods. BNP = brain-type natriuretic peptide; post-op = postoperative; pre-op = preoperaptive.

Figure 2.

Both (A) GLS and (B) FWS improve after congenital diaphragmatic hernia repair. P value is for comparisons among the pre-op, immediate post-op, and recovery periods. FWS = free-wall strain; GLS = global longitudinal strain; post-op = postoperative; pre-op = preoperaptive.