Are natriuretic peptides clinically useful as markers of heart failure?

A Clinical Study of the N-Terminal pro-Brain Natriuretic Peptide in Myocardial Injury after Neonatal Asphyxia

BACKGROUND

We aimed to study the changes of serum N-terminal pro-brain natriuretic to peptide (NT-proBNP) levels after asphyxia-induced myocardial injury in children and explore the relationship between serum NT-proBNP levels and neonatal asphyxia.

METHODS

One hundred and six cases of neonatal asphyxia were randomly selected for the study, including 46 severe cases with myocardial injury and 60 mild cases with no cardiac injury. Sixty-three healthy newborns were selected as the control group. The serum NT-proBNP level was detected using electrochemiluminescence. Creatine kinase MB (CK-MB) and serum sodium and calcium were measured simultaneously.

RESULTS

The serum NT-proBNP level in the myocardial injury group was significantly higher than that of the noncardiac injury and control groups (p < 0.01). Asphyxia serum NT-proBNP and cardiac enzymes were significantly correlated. The median value of neonatal NT-proBNP was 1491 pg/mL at postnatal Day 3 (P3) and 1077 pg/mL at postnatal Day 14 (P14). The cutoff value for children with myocardial injury was 3612.5 pg/mL; the area under the receiver operating characteristic curve was 0.80 (p < 0.001), with a sensitivity of 83.3%, a specificity of 80.5%, a positive predictive value of 82.8%, and a negative predictive value of 79.4%. After treatment, the serum NT-proBNP level in children with myocardial damage showed a significant decrease.

CONCLUSION

The serum NT-proBNP level can reflect myocardial injury in neonates with asphyxia and can guide its diagnosis.

The effect of coronary angioplasty on plasma NT-proBNP level in patients with and without arterial hypertension

AIMS

The purpose of the study was to assess the effect of percutaneous transluminal coronary angioplasty (PTCA) on plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) level in hypertensive and normotensive subjects with and without systolic left ventricular dysfunction.

METHODS AND RESULTS

Forty patients affected by ischemic heart disease and submitted to PTCA were studied. The patients were divided into four groups: group I - 10 patients with essential arterial hypertension (HT) and normal left ventricular ejection fraction (EF); group II - 10 patients with HT and EF < 55%; group III - 10 patients without HT and with normal EF; group IV - 10 patients without HT and with EF < 55%. Blood samples were collected twice: 24 h before and after PTCA. The plasma NT-proBNP concentrations increased significantly in group I (368+/-103 pg/ml vs 488 +/- 182 pg/ml; p < 0.05), in group III (257 +/- 107 pg/ml vs 447 +/- 198 pg/ml; p < 0.05), and in group IV (419 +/- 99 pg/ml vs 826 +/- 432 pg/ml; p < 0.05) 24 h after PTCA. There were significant differences in the relative change in plasma NT-proBNP concentrations between groups I and II, and between groups III and IV.

CONCLUSIONS

Successful coronary angioplasty results in a rise in plasma NT-proBNP concentration. The increase is less expressive in patients with systolic left ventricular dysfunction. The presence of hypertension does not affect NT-proBNP concentration after PTCA.

Amino-terminal pro-brain-type natriuretic peptide: heart or lung disease in pediatric respiratory distress?

OBJECTIVES

The aim of this study was to determine whether plasma levels of amino-terminal pro-brain natriuretic peptide (N-BNP) could differentiate between heart failure and lung disease among infants with acute respiratory distress. In addition, our aim was to determine whether plasma levels of N-BNP could be used to monitor the effects of treatment among infants with heart failure.

METHODS

Infants (age range: 1-36 months; median age: 10 months) who presented with respiratory distress underwent physical examination, plasma N-BNP measurement, and echocardiography within 24 hours after admission. Seventeen infants were finally diagnosed with acute heart failure and 18 with acute lung disease. Thirteen healthy infants served as a control group.

RESULTS

Plasma N-BNP levels were significantly higher for the infants with heart failure (median: 18452 pg/mL; range: 5375-99700 pg/mL) than for the infants with lung disease (median: 311 pg/mL; range: 76-1341 pg/mL). Among the infants with heart failure, there was a significant difference in plasma N-BNP levels before and after congestive heart failure treatment.

CONCLUSION

Among infants with respiratory distress, plasma N-BNP measurements can differentiate between acute heart failure and lung disease and can be used to monitor the effects of treatment for infants with heart failure.

Diagnostic accuracy and prognostic relevance of the measurement of cardiac natriuretic peptides: a review

BACKGROUND

The pathophysiologic and clinical relevance of cardiac natriuretic hormone (CNH) assays has been investigated in numerous experimental and clinical studies. Authors have sought to evaluate the diagnostic accuracy and prognostic relevance of the measurement of CNHs according to evidence-based laboratory medicine principles.

METHODS

In June 2003, we ran a computerized literature search on National Library of Medicine using keywords "ANP" and "BNP" and found more than 12 300 and 1200 articles, respectively. A more refined search with keywords "ANP or BNP assay" extracted approximately 7000 and 800 articles, respectively. Only studies specifically designed to evaluate the diagnostic accuracy and prognostic relevance of CNH measurements were selected from this huge mass of articles to be discussed in this review.

CONTENT

Several studies suggested that CNH assays may be clinically useful for the screening and classification of patients with heart failure, as a prognostic marker in cardiovascular disease, in the follow-up of patients with heart failure, and because they may reduce the need for further cardiac investigation. However, it is difficult to compare even the best-designed studies because not only did the authors evaluate different populations, they also used different gold standards.

CONCLUSIONS

CNH assays and conventional diagnostic work-ups provide complementary information for evaluation of the presence and severity of cardiac dysfunction and clinical disease. Several aspects of CNH assays are still to be elucidated, and further work is needed to carefully assess their diagnostic accuracy and prognostic value in cardiac disease.

Plasma concentrations of N-terminal pro-brain natriuretic peptide in control children from the neonatal to adolescent period and in children with congestive heart failure

OBJECTIVE

To determine plasma levels of N-terminal pro-brain natriuretic peptide (N-BNP) in control children to establish a normal age-dependent range from the neonatal period to adulthood. In addition, plasma concentrations of N-BNP were measured in children with congestive heart failure (CHF) and correlated with ejection fraction and clinical symptoms of heart failure.

METHODS

For establishing a normal age-dependent range of plasma N-BNP, venous blood samples were taken in 133 control patients from the neonatal period to adulthood (10 days-32 years) and in 31 children with CHF. Plasma N-BNP levels were determined by an enzyme immunoassay. In children (1 month-14 years) with CHF, plasma N-BNP levels were correlated to ejection fraction measured by echocardiography and clinical symptoms of heart failure using the Ross Score.

RESULTS

N-BNP levels in control children, adolescents, and adults did not show a significant age-related difference. In control children, the normal range was established between 150 (10th percentile) and 430 fmol/mL (90th percentile). Mean plasma N-BNP in control children was 311 fmol/mL (range: 74-654 fmol/mL). In 31 children with CHF, the plasma N-BNP levels were significantly higher (mean: 846; range: 219-2718) than in control children. N-BNP levels showed a negative correlation with the ejection fraction (r = -0.53) and a positive correlation with the clinical heart failure score (r = 0.74).

CONCLUSIONS

Plasma N-BNP levels reflect the severity of symptoms of heart failure and the impairment of cardiac function in children with CHF. In the future, determination of plasma N-BNP levels may be used as a helpful adjunct to monitor the effect of various treatments for CHF in children.