β-Receptor downregulation in congenital heart disease: a risk factor for complications after surgical repair?

Background. Neurohormonal activation in children with heart failure due to congenital heart disease leads to downregulation of myocardial β-receptors that may influence the postoperative course after cardiothoracic surgery. Methods. Myocardial biopsies of 26 children (aged 14 ± 4 months) were obtained from the right atrium during cardiac surgery. Patients were allocated to either of two groups based on the duration of their intensive care unit stay: group 1 comprised those who stayed less than 7 days (n = 17), whereas group 2 comprised those who stayed more than 7 days, plus 3 infants who died during the early postoperative course (n = 9). For β1- and β2-mRNA quantitation, real-time polymerase chain reaction with fluorescence-labeled products was used. Results. Values for myocardial β-receptor gene expression were twice as high in group 1 children compared with group 2 (β1-receptor 0.12 ± 0.07 versus 0.06 ± 0.03, p = 0.0016; β2-receptor 0.12 ± 0.07 versus 0.06 ± 0.03, p = 0.0071). β-Receptor gene expression in 16 children who received standard treatment for heart failure averaged lower than in the 10 children who received additional propranolol. Conclusions. β-Receptor downregulation due to congestive heart failure has an impact on the postoperative course in children with congenital disease and depends on heart failure therapy.