Changes in atrial natriuretic peptide levels during cardiac bypass in the fetal goat

The aim of this study is to evaluate the effect of fetal cardiac bypass on the production and secretion of fetal atrial natriuretic peptide (ANP) in the goat. Eighteen pregnant goats, at days 120 to 140 of gestation, were randomly divided into control (n = 8) and bypass (n = 10) groups. The control group underwent a sham procedure involving fetal sternotomy and cannulation. The bypass group underwent fetal cardiac bypass using a centrifugal pump for 30 min. Fetuses in the bypass group exhibited hypoxia, hypercapnia, and acidosis during and after cardiac bypass. The pulse index (PI) of the umbilical artery in the bypass group increased significantly after cardiac bypass compared with the control group. Tei indices of the left and right ventricles in the bypass group increased remarkably after cardiac bypass. Plasma troponin I levels in the bypass group increased significantly compared with that of the control group. Plasma ANP levels increased markedly in the bypass group after cardiac bypass, and the difference between two groups was significant. Transcriptional levels of ANP mRNA in the fetal heart elevated remarkably in the bypass group compared with the control group at 2 h after the bypass. A significant positive correlation between plasma ANP levels and Tei indices of the ventricles, plasma troponin I was observed (left ventricular Tei index, r = 0.606, P < 0.01; right ventricular Tei index, r = 0.581, P < 0.01; plasma troponin I, r = 0.275, P < 0.05). In conclusion, fetal cardiac bypass promoted the production and secretion of ANP and was associated with fetal cardiac dysfunction.