How to interpret cardiac biomarkers in children?

Cardiac biomarkers are used as first-line diagnostic tools in suspected myocardial injury and heart failure in adult patients. Their use in paediatric patients has been limited by variability caused by age, gender and the presence of an underlying congenital cardiac condition. There are established reference ranges for both NT-proBNP and troponin in healthy children, but these cannot be applied to all paediatric patients because of limited large studies focusing on children with congenital heart disease and/or cardiomyopathy.This article will focus on the pathophysiology of myocardial injury and heart failure in children and the subsequent cardiac biomarker correlation. It will explain how to interpret the biomarker assay levels obtained for both troponin and NT-proBNP and highlights the importance of a clear clinical question prior to requesting a cardiac biomarker assay level.Clinical cases outline scenarios that may prompt consideration of biomarker analysis in children and aims to equip the reader with an understanding of how to interpret the results.

Exercise prescription improves exercise tolerance in young children with CHD: a randomised clinical trial.

OBJECTIVE: The main objective of this study was to ascertain if a structured intervention programme can improve the biophysical health of young children with congenital heart disease (CHD). The primary end point was an increase in measureable physical activity levels following the intervention. METHODS: Patients aged 5-10 years with CHD were identified and invited to participate. Participants completed a baseline biophysical assessment, including a formal exercise stress test and daily activity monitoring using an accelerometer. Following randomisation, the intervention group attended a 1 day education session and received an individual written exercise plan to be continued over the 4-month intervention period. The control group continued with their usual level of care. After 4 months, all participants were reassessed in the same manner as at baseline. RESULTS: One hundred and sixty-three participants (mean age 8.4 years) were recruited, 100 of whom were male (61.3%). At baseline, the majority of the children were active with good exercise tolerance. The cyanotic palliated subgroup participants, however, were found to have lower levels of daily activity and significantly limited peak exercise performance compared with the other subgroups. One hundred and fifty-two participants (93.2%) attended for reassessment. Following the intervention, there was a significant improvement in peak exercise capacity in the intervention group. There was also a trend towards increased daily activity levels. CONCLUSION: Overall physical activity levels are well preserved in the majority of young children with CHD. A structured intervention programme significantly increased peak exercise capacity and improved attitudes towards positive lifestyle changes.

Risk factors for congenital heart disease: The Baby Hearts Study, a population-based case-control study.

We investigated the role of maternal environmental factors in the aetiology of congenital heart disease (CHD). A population-based case-control study (242 CHD cases, 966 controls) was conducted using an iPad questionnaire for mother with linkage to maternity and first trimester prescription records. Risk of CHD was associated with low maternal education (OR adjusted for confounders 1.59; 95% confidence interval [CI], 1.02-2.49), pregestational diabetes (OR 4.04; 95% CI 1.00-16.28), self-reported maternal clotting disorders (adjOR 8.55, 95%CI 1.51-48.44), prescriptions for the anticlotting medication enoxaparin (adjOR 3.22, 95%CI 1.01-10.22) and self-reported vaginal infections (adjOR 1.69, 95%CI 1.01-2.80). There was no strong support for the hypothesis that periconceptional folic acid supplements have a protective effect, but there was a protective effect of frequent consumption of folate rich fruits (adjOR 0.64, 95%CI 0.47-0.89). Compared to the most common pre-pregnancy dietary pattern, CHD risk was associated with a poor diet low in fruit and vegetables (adjOR 1.56, 95%CI 1.05-2.34). Mothers of cases reported more pregnancy related stress (adjOR 1.69; 95% CI 1.22-2.34) and multiple stressors (adjOR 1.94, 95%CI 0.83-4.53). We found no supportive evidence for CHD risk being associated with obesity, smoking, depression or antidepressant use in this population. Our findings add to the previous evidence base to show potential for public health approaches to help prevent CHD in future by modifying environmental factors. Independent confirmation should be sought regarding elevated CHD risk associated with maternal blood clotting disorders and their treatment, since we are the first to report this.