Factors associated with serum brain natriuretic peptide levels after the Fontan procedure

Abstract

Objective: Although a useful marker of heart failure in adults, the utility of brain natriuretic peptide concentration (BNP) for children after the Fontan procedure is not well studied.

Design: BNP was measured in 510 patients who were 6-18 years old in the Pediatric Heart Network Fontan cross-sectional study at a median of 8.2 years after Fontan. Patients underwent echocardiography, exercise testing, magnetic resonance imaging (MRI) and functional health status questionnaires. Associations of BNP with baseline patient characteristics, medical history and cross-sectional assessment were examined with multivariable linear regression analyses.

Results: The distribution of BNP was highly skewed, median 13.0 pg/mL (interquartile range: 7.1, 25.9), and was normalized with logarithmic transformation (logBNP). Among medical history variables, logBNP was greater in females (P= .02) and older patients (P < .001). Presence of pre-Fontan systolic ventricular dysfunction, greater number of post-Fontan complications, and thrombosis after Fontan were independently associated with higher logBNP (R(2) = 0.16). Age-adjusted logBNP was significantly related to Fontan connection type (lower with extracardiac conduits, higher with atriopulmonary connection; P < .001). Lower physical functioning health status (R(2) = 0.05), lower chronotropic index during exercise (R(2) = 0.17), indices of diastolic dysfunction measured by echocardiography (R(2) = 0.15), and higher total ventricular mass on MRI (R(2) = 0.33) were related to higher logBNP.

Conclusions: Despite a markedly abnormal circulation, BNP was variable but within a normal range in the majority of Fontan patients in this large outpatient cohort. Higher BNP was associated with several markers of suboptimal outcome, although associations were weak. The routine use of BNP as an outpatient surveillance tool in asymptomatic Fontan patients is not warranted.

Figure 1

Distribution of Brain natriuretic peptide (BNP) concentration excluding 4 patients with values exceeding 200 pg/ml.

Figure 2

Subgroup analysis of serum brain natriuretic peptide concentrations (BNP) by Fontan connection type. Mean ± SE of raw BNP adjusted for gender and age at enrollment APC=atriopulmonary connection, ECC=extracardiac conduit, ECLT=extracardiac lateral tunnel, ICLT=intracardiac lateral tunnel.