NTproBNP after Fontan anastomosis: Early versus late post-operative value

Abstract

NTproBNP assessment remains limited in congenital cardiology, particularly in patients with univentricular heart physiology who underwent total cavopulmonary connection (TCPC) where long-term prognosis is greatly related to ventricular function. To evaluate the NTproBNP after TCPC and seek a correlation with clinical and laboratory monitoring. A retrospective study was initiated on all TCPC patients born after 1991. Demographic, anatomical, echocradiography data and NTproBNP serum level were collected following the early post-operative period. Routine NTproBNP screening for these patients was initiated in our institution in 2008. NTproBNP Z-score was calculated based on our published equation from healthy children. Of a total of 46 patients who completed TCPC, 5 died post-operatively. All remaining 41 subjects had available NTproBNP beyond the immediate post-operative period and constituted the study population. NTproBNP was significantly elevated during the first post-operative year (Z-score 1.9 ± 1.17) compared to mid-term follow-up (3–5 years) (Z-score 1.23 ± 0.72), P = 0.03. Mean NTproBNP Z-score increased in the subsequent years to 1.6 ± 1.1 ( P = 0.21 vs year-1 post TCPC, and 0.06 vs mid-term). Z-scores > 2.0 were associated with a lower serum albumin (39.2 ± 3.3 vs 44.4 ± 4.4 mg/dL; P = 0.04), but not with other laboratory tests. There were however no identifiable predisposing clinical factors (i.e., ventricular morphology, age), preoperative hemodynamic data (PVRi, mean pulmonary artery pressure, Nakata index), surgical specifics (type of TCPC, presence of fenestration, pacemaker implantation), or postoperative events. The TCPC postoperative year is marked by a significant increase in the levels of NTproBNP. The observation does not seem to vary between left and right dominant ventricular anatomy, neither did it correlate with various parameters. NTproBNP improved in the mid-term follow-up.