Impact of Systemic Ventricular Morphology on (zlog-)NT-proBNP in Children Undergoing Staged Fontan Palliation

Background: As a marker of cardiac wall stress, NT-proBNP offers high prognostic and diagnostic potential in patients with univentricular hearts (UVH). However, the impact of systemic ventricular morphology on this biomarker during the different stages of Fontan palliation remains unclear.

Methods: Children who underwent systemic-to-pulmonary (SP) shunt, bidirectional cavopulmonary shunt (BCPS), or total cavopulmonary connection (TCPC) at our institution between 1994 and 2021 were identified. Subjects were included if they had an NT-proBNP measurement at most 7 days before surgery, or 6 months to 5 years after TCPC when presenting in a stable condition at our outpatient clinic. Age-adjusted z-scores (“zlog-NT-proBNP”) were calculated to allow comparison between subjects with systemic left ventricle (SLV) and systemic right ventricle (SRV), independent of the pronounced physiological decrease in NT-proBNP reference intervals with age.

Results: A total of 289 children met the eligibility criteria. Of these, 179 patients had a systemic right ventricle, while 110 had a systemic left ventricle. At each stage of Fontan palliation, zlog-NT-proBNP levels were significantly elevated in patients with SRV compared with those with SLV: before SP shunt (median 3.67 vs. 2.99, p = 0.025); before BCPS (median 3.38 vs. 1.72, p < 0.001); before TCPC (median 1.58 vs. 0.67 ng/L, p < 0.001); and after TCPC (median 1.67 vs. 0.78, p < 0.001). Furthermore, after Fontan completion, 96% of children with SLV demonstrated physiological NT-proBNP levels within the age-specific reference intervals (zlog-NT-proBNP ≤ +1.96). In contrast, 26% of subjects with SRV after TCPC revealed elevated zlog-NT-proBNP levels.

Conclusion: Systemic ventricular morphology highly affects NT-proBNP levels before, during and after staged Fontan palliation. When interpreting NT-proBNP levels in these patients, clinicians and future studies should consider that children with an SRV reveal higher NT-proBNP levels than those with an SLV.

Publication History

Article published online:
13 February 2024