Background Cyanotic patients have potential growth retardation and malnutrition due to hypoxemia and other reasons.Ghrelin is a novel endogenous growth hormone secretagogue that has effects on growth and cardiovascular activities.The aim of this study was to evaluate the plasma level and myocardial expression of ghrelin and insulin-like growth factor-1 (IGF-1) using an immature piglet model of chronic cyanotic congenital heart defects with decreased pulmonary blood flow.Methods Twelve weanling Chinese piglets underwent procedures of main pulmonary artery-left atrium shunt with pulmonary artery banding or sham operation as control. Four weeks later, hemodynamic parameters were measured.Enzyme-linked immunosorbent assay for plasma ghrelin and IGF-1 level measurement were performed. Ventricular ghrelin and IGF-1 mRNA expressions were measured by quantitative real-time polymerase chain reaction.Results Four weeks after surgical procedure, the cyanotic model produced lower arterial oxygen tension ((68.73 ±15.09) mmHg), arterial oxygen saturation ((82.35 ± 8.63)%), and higher arterial carbon dioxide tension ((51.83 ± 6.12)mmHg), hematocrit ((42.67 ± 3.83)%) and hemoglobin concentration ((138.17 ± 16.73) g/L) than the control piglets ((194.08 ± 98.79) mmHg, (96.43 ± 7.91)%, (36.9 ± 4.73) mmHg, (31.17 ± 3.71)%, (109.83 ± 13.75) g/L) (all P