B-type natriuretic peptide levels predict outcomes for children on extracorporeal life support after cardiac surgery

The frequency of postoperative BNP measurement and intervention threshold of BNP concentration in pediatric cardiac intensive care unit: a prospective multicenter observational study

PURPOSE

The purpose of this study is to investigate the current status of postoperative BNP measurement in the pediatric cardiac intensive care unit (PCICU).

METHODS

This was a prospective multicenter observational study. Children under 15 years old who underwent pediatric cardiac surgery were included. Postoperatively, all BNP measurement was collected in PCICU. We checked whether each BNP measurement was used for the decision-making of intervention or not. We divided the BNP measurements into 4 groups: group A 0-299 pg/ml (reference), group B 300-999 pg/ml, group C 1000-1999 pg/ml, group D ≧ 2000 pg/ml. We performed logistic regression analysis to compare the intervention ratio between group A and B, C, D. We also did multiple comparison analyses to compare the intervention ratio in each group.

RESULTS

Thirty-nine (15.8%) measurements were used as a criterion to intervene in all BNP measurements. There was no protocol for the measurement of BNP in all institutions. The number of BNP measurements in each group is as follows: group A 113 (45.9%), group B 81 (32.9%), group C 45 (18.3%), group D 7 (2.8%). The intervention ratio in each group was 6.2% (group A), 8.6% (group B), 44.4% (group C), and 71.4% (group D). The intervention ratio of group C and D were significantly higher than group A: (Odds ratio (95%CI): 12.1(4.8-33.9), p < 0.0001, 25.2(5.2-146.2), p < 0.0001). The result of multiple comparisons is similar to logistic regression analysis.

CONCLUSION

High BNP concentration, especially more than 1000 pg/ml, was more often intervened upon compared to that of less than 1000 pg/ml.

Biomarkers in pediatric heart disease

A biomarker is a characteristic that can be used as an indicator of a biological state. A biomarker can be a clinical observation, laboratory test or an imaging parameter. In this review, we discuss the use of biomarkers in differentiating cardiac from noncardiac disease; predicting the prognosis of patients with heart failure, pulmonary hypertension and dilated cardiomyopathy; diagnosing subclinical cardiac involvement in muscular dystrophy and postchemotherapy cancer patients; detecting acute rejection following heart transplantation; diagnosing Kawasaki disease; aiding the management of postoperative cardiac patients; and managing both common (tetralogy of Fallot) and complex (single-ventricle physiology) congenital heart diseases.

Clinical utility of B-type natriuretic peptide (NP) in pediatric cardiac surgery--a systematic review

BACKGROUND

NP is a biomarker that has been used in the diagnosis, management, and prognostication of a number of cardiovascular disorders in the pediatric population. The physiological role of this hormone is to allow the myocardium to adapt to stress or strain imposed by a volume and/or pressure load.

OBJECTIVE

The aim of this study was to determine the utility of preoperative and postoperative NP to predict outcome in pediatric patients undergoing cardiac surgery for structural congenital heart disease.

METHOD

We conducted a systematic review by searching three electronic databases using the search terms 'paediatric' or 'pediatric' and 'B-type natriuretic peptide'. Twenty peer-reviewed papers were included in the study.

RESULTS

Preoperative NP levels were associated with the severity of cardiac failure in several studies. Preoperative NPs also correlated with early postoperative outcome measures such as duration of cardiopulmonary bypass, duration of mechanical ventilation, presence of low cardiac output syndrome, length of stay in the intensive care unit and in one study, death. Early (within 24 h) postoperative NPs showed a stronger correlation than preoperative NPs to early postoperative adverse events.

CONCLUSION

NPs provide a simple, noninvasive and complementary tool to echocardiography that can be used to assist clinicians in the assessment and management of pediatric patients with congenital heart disease in the perioperative period.

Surgical resilience: a review of resilience biomarkers and surgical recovery

BACKGROUND

Two distinct and large bodies of literature exist on resilience that are of potential interest for surgical outcomes. First is the literature on the impact of resilience on surgical recovery and wound-healing. Second is the literature on biomarkers for resilience, which largely focuses on neuropeptide Y (NPY), testosterone and dehydroepiandrosterone (DHEA). Despite this activity, there is a dearth of literature linking these two bodies of research by investigating biomarkers for surgical resilience and its impact on surgical recovery. This paper reviews both bodies of literature within the context of surgical recovery.

METHOD

Literature searches within Medline and Embase were conducted for studies and previous reviews of resilience biomarkers and for the impact of individual resilience on surgical recovery. Reference lists of the reviews were searched for additional papers. No systematic review is yet possible due to the novelty of the use of resilience biomarkers within a surgical context.

RESULTS

This is the first review to explore a potential link between resilience biomarkers and surgical recovery. There are a number of biomarkers that correlate with individual resilience levels and resilient individuals exhibit better recovery trajectories following surgery, suggesting a novel use of such biomarkers for the identification of "surgical resilience".

CONCLUSION

By identifying surgical resilience, there is potential for utilising these biomarkers as prognostic indicators of likely recovery trajectories from surgery, which in turn complement individualised peri-operative management.

Preoperative B-type natriuretic peptide levels are associated with outcome after total cavopulmonary connection (Fontan)

OBJECTIVE

The study objective was to determine the association between preoperative B-type natriuretic peptide levels and outcome after total cavopulmonary connection. Surgical palliation of univentricular cardiac defects requires a series of staged operations, ending in a total cavopulmonary connection. Although outcomes have improved, there remains an unpredictable risk of early total cavopulmonary connection takedown. The prediction of adverse postoperative outcomes is imprecise, despite an extensive preoperative evaluation.

METHODS

We prospectively enrolled 50 patients undergoing total cavopulmonary connection. We collected preoperative clinical data, preoperative plasma B-type natriuretic peptide levels, and postoperative outcomes, including the incidence of an adverse outcome within 1 year of surgery (defined as death, total cavopulmonary connection takedown, or the need for cardiac transplantation).

RESULTS

The mean age of patients was 4.7 years (standard deviation, 2.1 years). The median (interquartile range) preoperative B-type natriuretic peptide levels were higher in patients who required total cavopulmonary connection takedown and early postoperative mechanical cardiac support (n = 3; median, 55; interquartile range, 42-121) compared with those with a good outcome (n = 47; median, 11; interquartile range, 5-17) (P < .05). A preoperative B-type natriuretic peptide level of 40 pg/mL or greater was highly associated with the need for total cavopulmonary connection takedown (sensitivity, 100%; specificity, 93%; P < .05), yielding a positive predictive value of 50% and a negative predictive value of 100%. Higher preoperative B-type natriuretic peptide levels also were associated with longer intensive care unit length of stay, longer hospital length of stay, and increased incidence of low cardiac output syndrome (P < .05).

CONCLUSIONS

Preoperative B-type natriuretic peptide blood levels are uniquely associated with the need for mechanical support early after total cavopulmonary connection and total cavopulmonary connection takedown, and thus may provide important information in addition to the standard preoperative assessment.

The effect of preoperative nutritional status on postoperative outcomes in children undergoing surgery for congenital heart defects in San Francisco (UCSF) and Guatemala City (UNICAR)

OBJECTIVE

The objective of this study was to determine the association between preoperative nutritional status and postoperative outcomes in children undergoing surgery for congenital heart defects (CHD).

METHODS

Seventy-one patients with CHD were enrolled in a prospective, 2-center cohort study. We adjusted for baseline risk differences using a standardized risk adjustment score for surgery for CHD. We assigned a World Health Organization z score for each subject's preoperative triceps skin-fold measurement, an assessment of total body fat mass. We obtained preoperative plasma concentrations of markers of nutritional status (prealbumin, albumin) and myocardial stress (B-type natriuretic peptide [BNP]). Associations between indices of preoperative nutritional status and clinical outcomes were sought.

RESULTS

Subjects had a median (interquartile range [IQR]) age of 10.2 (33) months. In the University of California at San Francisco (UCSF) cohort, duration of mechanical ventilation (median, 19 hours; IQR, 29 hours), length of intensive care unit stay (median, 5 days; IQR 5 days), duration of any continuous inotropic infusion (median, 66 hours; IQR 72 hours), and preoperative BNP levels (median, 30 pg/mL; IQR, 75 pg/mL) were associated with a lower preoperative triceps skin-fold z score (P < .05). Longer duration of any continuous inotropic infusion and higher preoperative BNP levels were also associated with lower preoperative prealbumin (12.1 ± 0.5 mg/dL) and albumin (3.2 ± 0.1; P < .05) levels.

CONCLUSIONS

Lower total body fat mass and acute and chronic malnourishment are associated with worse clinical outcomes in children undergoing surgery for CHD at UCSF, a resource-abundant institution. There is an inverse correlation between total body fat mass and BNP levels. Duration of inotropic support and BNP increase concomitantly as measures of nutritional status decrease, supporting the hypothesis that malnourishment is associated with decreased myocardial function.

Clinical trials in neonates and children: Report of the pulmonary hypertension academic research consortium pediatric advisory committee

Drug trials in neonates and children with pulmonary hypertensive vascular disease pose unique but not insurmountable challenges. Childhood is defined by growth and development. Both may influence disease and outcomes of drug trials. The developing pulmonary vascular bed and airways may be subjected to maldevelopment, maladaptation, growth arrest, or dysregulation that influence the disease phenotype. Drug therapy is influenced by developmental changes in renal and hepatic blood flow, as well as in metabolic systems such as cytochrome P450. Drugs may affect children differently from adults, with different clearance, therapeutic levels and toxicities. Toxicity may not be manifested until the child reaches physical, endocrine and neurodevelopmental maturity. Adverse effects may be revealed in the next generation, should the development of ova or spermatozoa be affected. Consideration of safe, age-appropriate tablets and liquid formulations is an obvious but often neglected prerequisite to any pediatric drug trial. In designing a clinical trial, precise phenotyping and genotyping of disease is required to ensure appropriate and accurate inclusion and exclusion criteria. We need to explore physiologically based pharmacokinetic modeling and simulations together with statistical techniques to reduce sample size requirements. Clinical endpoints such as exercise capacity, using traditional classifications and testing cannot be applied routinely to children. Many lack the necessary neurodevelopmental skills and equipment may not be appropriate for use in children. Selection of endpoints appropriate to encompass the developmental spectrum from neonate to adolescent is particularly challenging. One possible solution is the development of composite outcome scores that include age and a developmentally specific functional classification, growth and development scores, exercise data, biomarkers and hemodynamics with repeated evaluation throughout the period of growth and development. In addition, although potentially costly, we recommend long-term continuation of blinded dose ranging after completion of the short-term, double-blind, placebo-controlled trial for side-effect surveillance, which should include neurodevelopmental and peripubertal monitoring. The search for robust evidence to guide safe therapy of children and neonates with pulmonary hypertensive vascular disease is a crucial and necessary goal.

Elevated preoperative serum asymmetrical dimethylarginine (ADMA) is associated with poor outcomes after pediatric cardiac surgery

PURPOSE

Asymmetrical dimethylarginine (ADMA), an endogenous competitive inhibitor of nitric oxide synthase, is elevated in vascular pathologies such as hypertension and chronic kidney disease. Children undergoing cardiac surgery are at high risk of poor hemodynamic and renal outcomes secondary to cardiopulmonary bypass (CPB). This study tested the hypothesis that elevated preoperative ADMA levels are associated with overall worse clinical outcomes after pediatric CPB.

METHODS

This was a prospective, observational study of 100 patients aged from 2 weeks to 18 years who underwent cardiac surgery involving CPB. Serum ADMA levels were obtained preoperatively and on postoperative days zero through four. Clinical outcomes measured included acute kidney injury (AKI) by pRIFLE criteria, low cardiac output syndrome (LCOS), length of mechanical ventilation, hospital and ICU length of stay, unplanned reoperation, and mortality.

RESULTS

The 29 patients with an elevated preoperative ADMA were more likely to have prolonged mechanical ventilation, increased ICU and hospital length of stay, unplanned reoperation, and LCOS than those with a normal preoperative level. ADMA levels inversely correlated with estimated glomerular filtration rate (eGFR), but did not differ between patients with and without AKI after CPB. Preoperative ADMA levels correlated with hospital length of stay (r(s) = 0.289), ICU length of stay (r(s) = 0.308), and length of mechanical ventilation (r(s) = 0.402); [all p < 0.05]. ADMA levels before surgery had good predictive power for prolonged mechanical ventilation (AUC-ROC 0.809; 95 % CI 0.704, 0.914; p < 0.001).

CONCLUSIONS

Patients with elevated ADMA before surgery were more likely to have prolonged mechanical ventilation, develop LCOS, require an extended length of stay, and require reoperation. ADMA levels inversely correlated with eGFR, but did not predict AKI. Preoperative serum ADMA appears to identify pediatric cardiac surgery patients at risk of poor postoperative outcomes following CPB.

B-type Natriuretic Peptide: Diagnostic and Therapeutic Applications in Infants and Children

The natriuretic peptide system plays an active role in the regulation of fluid balance and systemic vascular resistance. Peptides of the natriuretic system produced through recombinant DNA technology are now available for clinical use including both atrial natriuretic peptide (ANP) and brain-type natriuretic peptide (BNP). Assays of BNP are available and may be used for both diagnostic and prognostic purposes in various clinical scenarios. The basic physiology of the natriuretic peptide system is presented, applications of BNP monitoring as a diagnostic tool are reviewed, and reports regarding the use of recombinant BNP in the pediatric population are discussed.

B-type natriuretic peptide predicts responses to indomethacin in premature neonates with patent ductus arteriosus

OBJECTIVES

To determine whether B-type natriuretic peptide (BNP) predicts indomethacin responsiveness in premature neonates with patent ductus arteriosus (PDA).

STUDY DESIGN

Premature neonates receiving indomethacin for an echocardiograhically large (diameter>1.5 mm) and clinically significant PDA were prospectively studied. All neonates underwent paired echocardiography and BNP measurements at baseline and 24 hours after each dose of indomethacin. After treatment, neonates who responded (with closed or insignificant PDA) and neonates who did not respond (with persistent significant PDA requiring surgical ligation) were compared.

RESULTS

Thirty-one premature neonates (mean gestational age, 30 weeks) underwent 119 paired echocardiography and BNP determinations. Mean BNP levels (1286+/-986 pg/mL) associated with significant PDA (n=96) were higher than those associated with closed or insignificant PDA (n=23; 118+/-124 pg/mL; P<.001). Twenty-three neonates responded and 8 neonates did not respond to indomethacin. Mean baseline BNP levels were higher in neonates who were non-responders (2234+/-991 pg/mL) than neonates who were responders (983+/-814 pg/mL; P=.001). A baseline BNP level>1805 pg/mL had a sensitivity rate of 88% and a specificity rate of 87% for predicting indomethacin non-responsiveness (P=.003).

CONCLUSIONS

High baseline BNP levels predict poor responses to indomethacin and the need for surgery in premature neonates with PDA.

Early elevations in B-type natriuretic peptide levels are associated with poor clinical outcomes in pediatric acute lung injury

OBJECTIVES

To determine B-type natriuretic peptide (BNP) levels in infants and children with acute lung injury (ALI), and to investigate associations between BNP levels and clinical outcome.

DESIGN

Prospective observational study.

SUBJECTS

After informed consent, plasma was collected from 48 pediatric patients on day 1 of ALI.

METHODOLOGY

Plasma BNP levels were measured by immunoassay on day 1 of ALI in 48 pediatric patients. Associations between BNP levels and outcome were determined.

RESULTS

The mean PaO(2)/FiO(2) at the onset of ALI was 155 (+/-74) and BNP values ranged from 5 to 2,060 pg/ml with a mean of 109 (+/-311). BNP levels were inversely correlated with ventilator-free days (Spearman rho -0.30, P = 0.04), and positively correlated with exhaled tidal volume (Spearman rho 0.44, P = 0.02). BNP levels were higher in patients receiving inotropic support (n = 12) than patients not receiving inotropic support (n = 33, P = 0.02). BNP levels were correlated with PRISM III scores (Spearman rho 0.55, P < 0.001) and PELOD scores (Spearman rho 0.4, P = 0.006). Mortality for the cohort was 15%. BNP levels were higher in non-survivors (n = 7) than survivors (n = 41, P = 0.055).

CONCLUSIONS

BNP levels are elevated in children with ALI/ARDS early in the disease course, and increased levels are associated with worse clinical outcome.