Biomarker responses during mid-term mechanical cardiac support in children

Background: The purpose of this study was to determine the effect of mid-term mechanical circulatory support on the natriuretic hormone system in children and to assess whether such changes are associated with myocardial recovery. Methods: Serial blood samples were collected from 19 children (median age 10.8 years, range 0.2 to 17.5 years), all supported with A pulsatile ventricular assist device (Berlin Heart EXCOR; median support time 55 days). Levels of NT-proBNP were analyzed before and 7 and 30 days after device implantation. In addition, we determined levels of mid-region proANP (MR-proANP) and BNP in 13 of the 19 children. Results: The actuarial survival rate to discharge, home was 84%. Two children could be weaned from the system, 14 reached heart transplantation, and 3 died during mechanical circulatory support. Serial measurements of NT-proBNP, BNP and MR-proANP showed a significant down-regulation of all three natriuretic peptides within the first week of support and a further decrease between Days 7 and 30. The lowest NT-proBNP level while on the device (250 pg/ml) was found in the child later weaned, who reached normal levels (71 pg/ml) within 12 weeks after weaning. Conclusions: Extremely high levels of natriuretic peptides reflect the severity of myocardial failure before device implantation. During mechanical support, the decline of natriuretic peptides appears to be a helpful additional tool in the pre-selection of potential weaning candidates.