B-type natriuretic peptide predicts adverse cardiovascular events in pediatric outpatients with chronic left ventricular systolic dysfunction

Cystatin C and body surface area are major determinants of the ratio of N-terminal pro-brain natriuretic peptide to brain natriuretic peptide levels in children

BACKGROUND

Production of N-terminal pro-brain natriuretic peptide (NT) and BNP is equimolar. Although NT clearance occurs only in the kidneys, BNP clearance occurs in the kidneys and other organs. This study tested the hypothesis that NT/BNP ratio in children may be independently related to cystatin C (CysC), a glomerular filtration rate marker, when diastolic function and age/body size are taken into consideration.

METHODS

The study included 430 children (5.3±4.9 years) with heart disease who had undergone cardiac catheterization and simultaneous BNP, NT, and CysC measurements. Pulmonary capillary wedge pressure (PCWP) was used as a ventricular diastolic stretch marker. Variables showing skewed distribution were transformed into a common logarithm.

RESULTS

Univariate regression revealed that logNT/BNP was affected by PCWP (r=-0.12) and logCysC (r=0.57). When age and the log of body surface area (BSA) were added to the stepwise regression, age was not adopted because of multicollinearity to logBSA, but PCWP (β=-0.10), logCysC (β=0.22), and logBSA (β=-0.66) were independent factors of logNT/BNP.

CONCLUSIONS

Renal dysfunction independently increased NT/BNP, whereas high BSA decreased it and is the greatest determinant of NT/BNP. The observation that high PCWP decreased NT/BNP may suggest that worsening heart failure slows BNP clearance from other organs, a compensatory pathway of heart failure. These factors need to be considered when assessing BNP and NT.

Bedside biomarkers in pediatric cardio renal injuries in emergency

Point of care testing (POCT) using biomarkers in the emergency department reduces turnaround time for clinical decision making. An ideal biomarker should be accurate, reliable and easy to measure with a standard assay, non-invasive, sensitive and specific with defined cutoff values. Conventional biomarkers for renal injuries include rise in serum creatinine and fluid overload. Recently, neutrophil gelatinase associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), cystatin C, interleukin-18 (IL-18) and liver fatty acid binding protein (L-FABP) have been studied extensively for their role in acute kidney injury associated with various clinical entities. Biochemical markers of ischaemic cardiac damage commonly used are plasma creatine kinase and cardiac troponins (cTn). Clinically valuable cardiac markers for myocardial injury in research at present comprise BNP/NT-proBNP and to a lesser extent, CRP, which are independent predictors of adverse events including death and heart failure. Current status of point of care biomarkers for diagnosis and prognostication of renal and cardiac injuries in pediatric emergency care is appraised in this review.

B-type natriuretic peptide trends after pediatric heart transplantation

BNP is increasingly utilized in the management of pediatric HT recipients. Performing a retrospective single-center chart review, we sought to describe BNP changes during the first year after HT and identify factors that affect its trend. After exclusion for rejection, 316 BNP levels from 50 patients were evaluated. BNP underwent an exponential decline 120 days after HT followed by a plateau. Log10 BNP decline strongly correlated with time (r = -0.70, p < 0.0001). Initial BNP was less in pretransplant VAD (p = 0.0016) and lower post-HT inotrope use (p = 0.0043). Infant recipients, IT >4 h, and those bridged medically were associated with higher plateau BNP. Multivariable logistic regression demonstrated IT >4 h independently predicted plateau BNP in the upper quartile (OR 7.1, p = 0.02). No significant change in BNP coincided with rejection (N = 6 patients) without severe hemodynamic compromise. BNP correlated modestly with right atrial pressure (r = 0.4652, p < 0.0001) and pulmonary capillary wedge pressure (r = 0.2660, p < 0.001), but poorly with echocardiogram (r = -0.18, p = 0.003). Trending BNP could help provide insight into how the graft recovers after HT and IT >4 h independently predicted higher plateau BNP and may reflect subtle changes in graft performance.

Heart transplantation in pediatric cardiomyopathies

Cardiomyopathies represent an uncommon but serious cause of heart disease in the pediatric population and can be categorized as dilated, hypertrophic, restrictive and left ventricular non-compaction. Each of these subtypes has multiple potential genetic etiologies in addition to possible non-genetic causes. Many patients with cardiomyopathies can benefit from transplantation, although there is not insignificant morbidity and mortality for those patients. Outcomes both prior to and following transplantation depend on the underlying etiology, the amount of support needed prior to transplantation and the illness severity of the patient prior to transplantation. Mechanical circulatory support is frequently used to bridge patients to transplantation, and newer technologies are currently in development.

Factors associated with serum B-type natriuretic peptide in infants with single ventricles

Data regarding the value of B-type natriuretic peptide (BNP) measurements in infants with a single-ventricle (SV) physiology are lacking. This analysis aimed to describe the BNP level changes in infants with an SV physiology before and after superior cavopulmonary connection (SCPC) surgery. Levels of BNP were measured by a core laboratory before SCPC (at 5.0 ± 1.6 months) and at the age of 14 months during a multicenter trial of angiotensin-converting enzyme inhibition therapy for infants with SV. Multivariable longitudinal analysis was used to model the associations between BNP levels and three sets of grouped variables (echocardiography, catheterization, growth). Multivariable analysis was performed to assess associations with patient characteristics at both visits. Associations between BNP levels and neurodevelopmental variables were investigated at the 14 month visit because neurodevelopmental assessment was performed only at this visit. The BNP level was significantly higher before SCPC (n = 173) than at the age of 14 months (n = 134). The respective median levels were 80.8 pg/ml (interquartile range [IQR], 35-187 pg/ml) and 34.5 pg/ml (IQR, 17-67 pg/ml) (p < 0.01). A BNP level higher than 100 pg/ml was present in 72 subjects (42 %) before SCPC and in 21 subjects (16 %) at the age of 14 months. In the 117 patients who had BNP measurements at both visits, the median BNP level decreased 32 pg/ml (IQR, 1-79 pg/ml) (p < 0.01). In the longitudinal multivariable analysis, higher BNP levels were associated with a higher end-systolic volume z-score (p = 0.01), a greater degree of atrioventricular (AV) valve regurgitation (p < 0.01), a lower weight z-score (p < 0.01), and a lower length z-score (p = 0.02). In multivariable analyses, a higher BNP level at the age of 14 months was associated with arrhythmia after SCPC surgery (p < 0.01), a prior Norwood procedure (p < 0.01), a longer hospital stay after SCPC surgery (p = 0.04), and a lower Bayley psychomotor developmental index (p = 0.02). The levels of BNP decreases in infants with SV from the pre-SCPC visit to the age of 14 months. A higher BNP level is associated with increased ventricular dilation in systole, increased AV valve regurgitation, impaired growth, and poorer neurodevelopmental outcomes. Therefore, BNP level may be a useful seromarker for identifying infants with SV at risk for worse outcomes.

Natriuretic peptides: molecular biology, pathophysiology and clinical implications for the cardiologist

Natriuretic peptides (NPs) counter the effects of volume overload or adrenergic activation of the cardiovascular system. They are able to induce arterial vasodilatations, natriuresis and diuresis, and they reduce the activities of the renin-angiotensin-aldosterone system and the sympathetic nervous system. However, in addition to wall stress, other factors have been associated with elevated natriuretic peptide levels. Since 2000, because of their characteristics, NPs have become quantitative plasma biomarkers of heart failure. Nowadays, NPs play an important role not only in the diagnosis of heart failure, but also for a prognostic purpose and a guide to medical therapy. Finally, a new drug that modulates the NP system or recombinant analogs of NPs are now available in patients with heart failure.

Tissue Doppler septal Tei index indicates severity of illness in pediatric patients with congestive heart failure

The Doppler Tei index is an independent predictor of outcomes in adult heart failure. Tissue Doppler imaging (TDI) may be a superior method to measure the Tei index in children because it is less affected by heart rate variability. We hypothesized that the TDI Tei index reflects severity of illness in pediatric heart failure. Twenty-five pediatric heart failure patients were prospectively enrolled. Listing for heart transplantation or death were the outcomes used to define severity of illness. Baseline demographics, brain natriuretic peptide (BNP), and standard echocardiographic and TDI-derived parameters were analyzed to determine outcome indicators. Ten of the 25 patients (40%) were listed for transplantation. There were no deaths. Multivariate analysis combining age, heart rate, standard echocardiographic parameters, and BNP resulted in shortening fraction (p = 0.002) as the best indicator of listing for transplantation (R(2) = 0.32). A second multivariate analysis combining age, heart rate, TDI parameters, and BNP resulted in age (p = 0.03) and septal Tei index (p = 0.03) as the best predictive model (R(2) = 0.36). The area under the receiver operating characteristic (ROC) curve for septal Tei index was 0.84 (95% confidence interval = 0.64-0.96,), and it was comparable with the ROC curve for shortening fraction, p = 0.76. Optimal values of sensitivity (100%) and specificity (60%) were obtained with septal Tei index values >0.51. The TDI septal Tei index is an indicator of disease severity in pediatric heart failure patients and offers potential advantages compared with standard echocardiographic measures of left-ventricular ejection.

Cardiomyopathies encountered commonly in the teenage years and their presentation

Cardiomyopathy encompasses a broad range of inherited and acquired abnormalities affecting the myocardium. This heterogeneous group of disorders is an important cause of morbidity and mortality in the adolescent patient as a result of the presence of systolic or diastolic dysfunction, as well as the risk of coexisting arrhythmias and sudden cardiac death. It is important for the primary care physician involved in the care of adolescents to understand the different causes of cardiomyopathy and their typical clinical presentations. The cause, pathogenesis, clinical presentation, and diagnostic evaluation for adolescents with cardiomyopathy are reviewed. An overview of treatment modalities is also presented.

Clinical implications of serial serum N-terminal prohormone brain natriuretic peptide levels in the prediction of outcome in children with dilated cardiomyopathy

N-terminal prohormone brain natriuretic peptide (NT-proBNP) is known to be valuable as a prognostic marker for the management of heart failure. This study aimed to assess the serial changes of serum NT-proBNP levels as a prognostic factor for outcomes of pediatric dilated cardiomyopathy (DC). A retrospective study reviewed echocardiographic measurements and serum NT-proBNP levels obtained at the time of diagnosis, 3 and 6 months after diagnosis, and at the last follow-up in 68 children with DC. They were classified into 3 groups according to the last follow-up of the left ventricular (LV) function: group I (n = 37) with LV fractional shortening (FS) ≥25%, group II (n = 15) with 10% ≤ LVFS < 25%, and group III (n = 16) with LVFS <10% or cardiac death. The median age at diagnosis was 30 months and median duration of follow-up was 45 months (range 8 to 108 months). The origin of DC varied. Serial serum NT-proBNP levels showed statistically significant differences among the 3 groups. Although initial levels of serum NT-proBNP at diagnosis were not different from each other, group III maintained a higher NT-proBNP level throughout the duration of the follow-up. On multivariate Cox analysis, only the NT-proBNP level at 3 months was a significant predictor of an adverse outcome (hazard ratio 2.012, p = 0.028). The percent changes of NT-proBNP from diagnosis were not significant. Patients with DC with a serum NT-proBNP level ≥681 pg/ml at 3 months after diagnosis showed an increased risk of severe LV dysfunction or cardiac death (p <0.001, area under the curve = 0.846). In conclusion, the level of NT-proBNP in serum at 3 months after diagnosis could predict an adverse outcome in pediatric DC and could be used as a guide for long-term treatment plans.

Evaluation by N-terminal prohormone of brain natriuretic peptide concentrations and ross scoring of the efficacy of digoxin in the treatment of heart failure secondary to congenital heart disease with left-to-right shunts

This study aimed to evaluate the effectiveness of digoxin in children with heart failure secondary to left-to-right shunt lesions and normal left ventricular systolic function. The study registered 37 such patients (ages 10 days to 24 months, groups 1 and 2) and used 20 healthy children as a control group (group 3). Left ventricular systolic function, as assessed by conventional echocardiography, was normal in all the subjects. Congestive heart failure was diagnosed by clinical evaluation and modified Ross scoring. Plasma N-terminal prohormone of brain natriuretic peptide (NT-proBNP) concentrations and complete blood counts were assessed in all the children. Group 1 was treated with digoxin, enalapril, and furosemide and group 2 with enalapril and furosemide. Approximately 1 month after starting treatment, the patients were reevaluated by physical and echocardiographic examinations, modified Ross scoring, plasma NT-proBNP concentrations, and complete blood counts. The pre- and posttreatment Ross scores of group 1 (p = 0.377) and group 2 (p = 0.616) did not differ significantly. The NT-proBNP values in both groups decreased after treatment (p = 0.0001). The pre- and posttreatment NT-proBNP values did not differ significantly in group 1 (p = 0.094)) and group 2 (p = 0.372). The pretreatment NT-proBNP values in groups 1 and 2 (p = 0.0001) were significantly higher than in the control group (p = 0.003). A smaller difference was observed between posttreatment NT-proBNP values in group 1 and the control group (p = 0.045). We found no significant difference between the posttreatment NT-proBNP values of group 2 and those of the control group (p = 0.271). The study showed that both treatments currently used to treat heart failure secondary to congenital heart disease with left-to-right shunts and preserved left ventricular systolic function are effective and do not differ significantly. Thus, digoxin does not provide any extra benefit in the treatment of such patients.

B-type natriuretic peptide levels predict outcomes in infants undergoing cardiac surgery in a lesion-dependent fashion

OBJECTIVE

B-type natriuretic peptide is used in the diagnosis, risk stratification, and management of adult patients with cardiac disease. However, its use in infants with congenital heart disease has been limited, particularly in the perioperative period. Our objective was to determine the alterations in perioperative B-type natriuretic peptide levels and their predictive value on postoperative outcomes, in infants undergoing congenital heart surgery.

METHODS

We prospectively enrolled 115 patients: 24 with univentricular heart disease undergoing a modified Norwood procedure, 11 with d-transposition of the great arteries, 55 with hemodynamically important left-to-right shunt, and 25 with tetralogy of Fallot undergoing primary repair. Clinical data and B-type natriuretic peptide samples were collected before and 2, 12, and 24 hours after cardiopulmonary bypass. Univariate analysis and multivariate linear regression analysis were performed.

RESULTS

The perioperative B-type natriuretic peptide levels were lesion specific. Patients with d-transposition of the great arteries and univentricular heart disease had high preoperative B-type natriuretic peptide levels that decreased postoperatively, and those with hemodynamically important left-to-right shunts and tetralogy of Fallot had lower preoperative levels that increased during the first 12 hours postoperatively. The patients with univentricular heart disease with an adverse outcome had a significantly greater 24-hour B-type natriuretic peptide level than those without (P < .05). Those with hemodynamically important left to right shunts and an adverse outcome had a greater 12-hour B-type natriuretic peptide level than those without (P < .05). A 12-hour postoperative/preoperative ratio greater than 45 was 100% sensitive and 82% specific for an adverse outcome in the patients with tetralogy of Fallot.

CONCLUSIONS

The perioperative changes in B-type natriuretic peptide levels and their ability to predict outcomes are lesion-specific. Characterization of these changes might be useful in caring for infants after congenital heart surgery.

Cardiomyopathies in children

Cardiomyopathy (CMP) is a heterogeneous disease caused by a functional abnormality of the cardiac muscle. CMP is of 2 major types, dilated and hypertrophic, and is further classified as either primary or secondary. Secondary CMP is caused by extrinsic factors, including infection, ischemia, hypertension, and metabolic disorders. Primary CMP is diagnosed when the extrinsic factors of secondary CMP are absent. Furthermore, the World Health Organization, American Heart Association, and European Cardiology Association have different systems for clinically classifying primary CMP. Primary CMP is rare and associated with a family history of the disease, implying that genetic factors might affect its incidence. In addition, the incidence of CMP varies widely according to patient ethnicity. Genetic testing plays an important role in the care of patients with CMP and their families because it confirms diagnosis, determines the appropriate care for the patient, and possibly affects patient prognosis. The diagnosis and genetic identification of CMP in patients' families allow the possibility to identify novel genes that may lead to new treatments. This review focuses on the epidemiology, pathophysiology, diagnosis, and treatment of CMP, with the aim of providing pediatricians with insights that may be helpful in the early identification and management of idiopathic CMP in children.

Outcomes of children following a first hospitalization for dilated cardiomyopathy

BACKGROUND

We hypothesized that children with dilated cardiomyopathy who require hospital admission are at increased risk for death or transplantation during their first hospitalization and in the first year that follows. We also assessed the value of routine data collected during that time to predict death or the need for transplantation prior to discharge and within 1 year of admission.

METHODS AND RESULTS

We conducted a retrospective review of 83 pediatric patients with dilated cardiomyopathy whose initial hospitalization fell between 2004 and 2009. The mean age at hospitalization was 7 years. The majority of patients demonstrated moderate or severe left ventricular dysfunction on initial echocardiogram (80%) and/or the need for intravenous inotropes within 7 days of hospital admission (69%). Five patients (6%) died, and 15 (18%) were transplanted in the initial hospitalization. At 1 year, 11/71 (15%) had died, and 27/71 (38%) were transplanted. The overall freedom from death, transplantation, or rehospitalization at 1 year following admission was 21%. Fractional shortening, left ventricular ejection fraction, serum cholesterol, uric acid, mixed venous saturation, and atrial filling pressures were all predictive of death or transplantation during the initial hospitalization. Left ventricular ejection fraction was predictive of death or transplantation at 1 year.

CONCLUSIONS

The first hospitalization for dilated cardiomyopathy marks a period of high risk for clinical decline, end stage heart failure, and the need for cardiac transplantation. Echocardiographic function and hemodynamic and serum measurements may aid in predicting outcomes. Despite medical management, most patients will be rehospitalized and/or require cardiac transplantation within 1 year of admission.

B-type natriuretic peptide and rebound during treatment for persistent pulmonary hypertension

OBJECTIVE

To investigate whether serum B-type natriuretic peptide (BNP) is a useful biomarker in evaluating the course of persistent pulmonary hypertension of the newborn (PPHN) and the effectiveness of treatment.

STUDY DESIGN

Prospective follow-up study of infants with clinical and echocardiographic signs of PPHN, who were treated with inhaled nitric oxide (iNO). Of 24 patients with PPHN who were treated, serum BNP levels were determined longitudinally in 21. BNP levels were compared between infants with (n = 6) and without rebound PPHN (n = 15).

RESULTS

BNP levels in all infants with PPHN were not significantly different at the initial start of iNO. BNP levels decreased in both groups during iNO treatment. In the infants in whom rebound PPHN developed after weaning from iNO, a significantly higher increase was found in BNP (283 pmol/L to 1232 pmol/L) compared with that in infants without rebound (98 pmol/L to 159 pmol/L). This occurred before the onset of clinical deterioration. BNP again decreased significantly after iNO treatment was restarted.

CONCLUSIONS

BNP, a biomarker of cardiac ventricular strain, proved to be useful in evaluating the efficacy of PPHN treatment, and moreover, BNP helps to predict a rebound of PPHN.

Current applications and Future Needs for Biomarkers in Pediatric Cardiomyopathy and Heart Failure: Summary From The Second International Conference On Pediatric Cardiomyopathy

Biomarkers have established an important role in the diagnosis and prognosis of heart failure in adults, with early indications being that their sensitivity and specificity will be similar in the pediatric population. Since early detection of remodeling is vital to preemptive management in cardiomyopathy and in heart disease arising from congenital lesions, biomarkers may offer a means of identifying high risk patients before they develop symptoms. Although in current use, natriuretic peptides high sensitivity troponins, and C-reactive protein need to have their applications more clearly defined in pediatrics, by evidence based guidelines. Exploratory work should meanwhile continue to define the risk of disease progression in patients with dilated cardiomyopathy, and of sudden death in hypertrophic cardiomyopathy based on biomarker profiles. Further research into the interaction of the genetic basis of disease and proteomic biomarkers will be a valuable means of assessing the importance of different pathways of disease related ventricular remodeling.

Biomonitors of cardiac injury and performance: B-type natriuretic peptide and troponin as monitors of hemodynamics and oxygen transport balance

Serum biomarkers, such as B-type natriuretic peptide and troponin, are frequently measured in the cardiac intensive care unit. A review of the evidence supporting monitoring of these biomarkers is presented.

DESIGN

A search of MEDLINE, PubMed, and the Cochrane Database was conducted to find literature regarding the use of B-type natriuretic peptide and troponin in the cardiac intensive care setting. Adult and pediatric data were considered.

RESULTS AND CONCLUSION

Both B-type natriuretic peptide and troponin have demonstrated utility in the intensive care setting but there is no conclusive evidence at this time that either biomarker can be used to guide inpatient management of children with cardiac disease. Although B-type natriuretic peptide and troponin concentrations can alert clinicians to myocardial stress, injury, or hemodynamic alterations, the levels can also be elevated in a variety of clinical scenarios, including sepsis. Observational studies have demonstrated that perioperative measurement of these biomarkers can predict postoperative mortality and complications.

RECOMMENDATION AND LEVEL OF EVIDENCE

(class IIb, level of evidence B): The use of B-type natriuretic peptide and/or troponin measurements in the evaluation of hemodynamics and postoperative outcome in pediatric cardiac patients may be beneficial.

Growth differentiation factor 15: an additional diagnostic tool for the risk stratification of developing heart failure in patients with operated congenital heart defects?

BACKGROUND

Many young adults who have congenital heart defects develop heart failure despite corrective surgeries. Growth differentiation factor 15 (GDF-15) has an established role as a marker for risk stratification and mortality both in patients after acute myocardial infarction and in patients with heart failure. Our aim was to establish a role for GDF-15 for monitoring heart failure in operated congenital heart defects (ACHD). This potential biomarker was validated through comparison with maximal oxygen uptake (VO(2max)) and to another biomarker, N-terminal pro-brain natriuretic peptide (NT-proBNP).

METHODS

A total of 317 ACHD patients (129 females) with an average age of 26.5 ± 8.5 years (mean ± SD) enrolled in the study. We studied the relation between GDF-15 and NT-proBNP and VO(2max%) (percent predicted for age and gender). The cutoffs for the groups were as follows: NT-proBNP <100, 100 to 300, and >300 pg/mL; VO(2max%) <65%, 65% to 85%, and >85% of predicted normal.

RESULTS

Significant differences in mean GDF-15 levels were found between the NT-proBNP <100 and NT-proBNP >300 groups, as well as between the 100 to 300 and the >300 groups. For VO(2max%), significant differences were found in GDF-15 levels between <65% and >85% and between <65% and 65% to 85%, respectively. The lowest mean GDF-15 was found in groups with NT-proBNP <100 pg/mL and VO(2max%) >85%. The highest mean GDF-15 was found in the groups with NT-proBNP >300 pg/mL and VO(2max%) <65%. A subgroup analysis, including 82 patients with operated tetralogy of Fallot, showed that patients in the New York Heart Association I class have significantly lower NT-proBNP and GDF-15 level and markedly higher VO(2max) compared with the patients in higher New York Heart Association class.

CONCLUSION

Growth differentiation factor 15 might be used as a surrogate marker for latent heart failure and could help to identify patients with ACHD who are at risk for developing heart failure, even if they are clinically asymptomatic.

Relationship of brain natriuretic peptide concentrations to left ventricular function and adverse outcomes in children with end-stage renal disease undergoing hemodialysis

B-type natriuretic peptide (BNP) is a biomarker of cardiovascular disease that is common in adults with chronic kidney disease (CKD). However, in children with CKD, the range and predictive power of BNP concentrations are not known. We aimed to determine the effect of HD on BNP, as well as the prognostic impact of BNP, in end-stage renal disease (ESRD) children undergoing hemodialysis (HD). Thirty-five children with chronic renal failure (16 boys age 12.1 ± 3.7 years) on maintenance HD were included. BNP level was measured, and Doppler echocardiography was performed 30 min before (pre-HD BNP) and 30 min after (post-HD BNP) HD in each patient. An adverse event was defined as all-cause death and heart failure hospitalization. The median pre-HD BNP, the post-HD BNP, and the change in BNP were, respectively, 240 pg/ml (72 to 3346), 318 pg/ml (79 to 3788), and 9 pg/ml (-442 to 1889). Pre-HD BNP concentration was negatively correlated with left ventricular (LV) ejection fraction (r = -0.41, P = 0.018). During a mean follow-up of 39 ± 14 months, 6 patients died, and 3 were hospitalized for heart failure. Using univariate analysis, BNP before and after HD as well as Doppler tissue imaging velocities had a strong graded relationship with adverse events. Cox proportional hazards model demonstrated that pre-HD body weight (P = 0.008), pre-HD BNP (P = 0.011), and post-HD BNP (P = 0.038) remained independent predictors of adverse outcome. Even in case of ESRD, BNP still strongly correlated with LV systolic and diastolic dysfunction and was associated with mortality in HD children.

Indications for heart transplantation in congenital heart disease

In this review we have looked at indications for cardiac transplantation in congenital heart disease. An outline of the general principles of the use of transplant as a management strategy both as a first line treatment and following other surgical interventions is discussed. We explore the importance of the timing of patient referral and the evaluations undertaken, and how the results of these may vary between patients with congenital heart disease and patients with other causes of end-stage heart failure. The potential complications associated with patients with congenital heart disease need to be both anticipated and managed appropriately by an experienced team. Timing of transplantation in congenital heart disease is difficult to standardize as the group of patients is heterogeneous. We discuss the role and limitations of investigations such as BNP, 6 minute walk, metabolic exercise testing and self estimated physical functioning. We also discuss the suitability for listing. It is clear that congenital heart patients should not be considered to be at uniform high risk of death at transplant. Morbidity varies greatly in the congenital patient population with the failing Fontan circulation having a far higher risk than a failing Mustard circulation. However the underlying issue of imbalance between donor organ supply and demand needs to be addressed as transplant teams are finding themselves in the increasingly difficult situation of supporting growing numbers of patients with a diverse range of pathologies with declining numbers of donor organs.

Effectiveness of serial increases in amino-terminal pro-B-type natriuretic peptide levels to indicate the need for mechanical circulatory support in children with acute decompensated heart failure

We sought to determine prospectively whether serial assessment of the natriuretic peptide prohormone, amino-terminal pro-B-type natriuretic peptide (NT-pro-BNP), correlated with clinical severity and outcomes in children hospitalized for acute decompensated heart failure (ADHF). Patients (>1 month of age) admitted from 2005 to 2007 with ADHF requiring intravenous vasoactive/diuretic therapy for ADHF were eligible. Serum NT-pro-BNP levels were obtained within 24 hours of admission and at prespecified intervals, and clinical caregivers were blinded to these levels. End points included hospital discharge, death or cardiac transplantation, and care escalation including the need for mechanical circulatory support (MCS) was noted. Twenty-four patients were enrolled: 22 survived to hospital discharge and 2 died. Ten required MCS (of which 6 underwent cardiac transplantation). Two patients underwent transplantation without MCS. For the entire cohort, NT-pro-BNP levels peaked at days 2 to 3 after admission, with a subsequent gradual decrease until discharge. However, for those who did require MCS, NT-pro-BNP failed to decrease consistently until after MCS initiation. At discharge, NT-pro-BNP levels were significantly decreased from admission levels but remained well above normal for all patients. Single-point NT-pro-BNP levels on admission did not correlate with independently assessed clinical scores of heart failure severity or predict the need for MCS in this cohort. In conclusion, serial NT-pro-BNP levels demonstrated an incremental trend after 48 hours in patients who went on to require MCS but decreased in all other patients and may therefore assist the decision to initiate or avoid MCS after admission for pediatric ADHF.

Outpatient management of pediatric heart failure

The management of heart failure in children is becoming a specialized discipline within pediatric cardiology. Unlike the treatment of heart failure in adults, for which an extensive body of literature supports current treatment regimens, management of heart failure in children is largely guided by extrapolation from adult studies and expert opinion. This review focuses on the current state-of-the-art with respect to the outpatient management of heart failure in children.

Plasma B-type natriuretic peptides in children with cardiovascular diseases

Natriuretic peptides (NP) are released from the heart in response to pressure and volume overload. The biologic properties of NPs include counterregulation of the rennin-angiotensin-aldosterone pathway and a decrease in sympathetic tone resulting in diuresis, natriuresis, and vasodilation. Natriuretic peptides help to maintain fluid balance and blood pressure in a healthy physiologic range. The B-type natriuretic peptide (BNP) and its N-terminal precursor (NTpBNP) have become important diagnostic biomarkers of cardiovascular diseases (CVDs) in adults. Although many studies suggest that BNP also is a reliable test for diagnosing significant CVDs in children, data are lacking on whether additional use of BNP increases diagnostic accuracy and predicts prognosis. This comprehensive review describes the utility of BNP and NTpBNP for various CVDs of the neonatal and pediatric age groups. Because BNP is not a stand-alone test, it should not replace history, physical examination, or clinical judgment, but it has a clear value in adding details to the whole story for children, thus enabling the front-line physicians to make a diagnosis, especially in the acute care setting.

B-type natriuretic peptide: perioperative patterns in congenital heart disease

OBJECTIVE

B-type natriuretic peptide (BNP) has diagnostic, prognostic, and therapeutic roles in adults with heart failure. BNP levels in children undergoing surgical repair of congenital heart disease (CHD) were characterized broadly, and distinguishable subgroup patterns delineated.

DESIGN

Prospective, blinded, observational case series.

SETTING

Academic, tertiary care, free-standing pediatric hospital.

PATIENTS

Children with CHD; controls without cardiopulmonary disease. Interventions. None.

MEASUREMENTS

Preoperative cardiac medications/doses, CHD lesion types, perioperative BNP levels, intraoperative variables (lengths of surgery, bypass, cross-clamp), postoperative outcomes (lengths of ventilation, hospitalization, open chest; averages of inotropic support, central venous pressure, perfusion, urine output; death, low cardiac output syndrome (LCOS), cardiac arrest; readmission; and discharge medications).

RESULTS

Median BNP levels for 102 neonatal and non-neonatal controls were 27 and 7 pg/mL, respectively. Serial BNP measures from 105 patients undergoing CHD repair demonstrated a median postoperative peak at 12 hours. The median and interquartile postoperative 24-hour average BNP levels for neonates were 1506 (782-3784) pg/mL vs. 286 (169-578) pg/mL for non-neonates (P < 0.001). Postoperative BNP correlated with inotropic requirement, durations of open chest, ventilation, intensive care unit stay, and hospitalization (r = 0.33-0.65, all P < 0.001). Compared with biventricular CHD, Fontan palliations demonstrated lower postoperative BNP (median 150 vs. 306 pg/mL, P < 0.001), a 3-fold higher incidence of LCOS (P < 0.01), and longer length of hospitalization (median 6.0 vs. 4.5 days, P= 0.01).

CONCLUSIONS

Perioperative BNP correlates to severity of illness and lengths of therapy in the CHD population, overall. Substantial variation in BNP across time as well as within and between CHD lesions limits its practical utility as an isolated point-of-care measure. BNP commonly peaks 6-12 hours postoperatively, but the timing and magnitude of BNP elevation demonstrates notable age-dependency, peaking earlier and rising an order of magnitude higher in neonates. In spite of higher clinical acuity, non-neonatal univentricular CHD paradoxically demonstrates lower BNP levels compared with biventricular physiologies.

Serial measurements of serum NT-proBNP as markers of left ventricular systolic function and remodeling in children with heart failure

BACKGROUND

Increasing serum levels of N-terminal pro-hormone brain natriuretic peptide (NT-proBNP) are associated with worsening heart failure (HF) in adults. We determined whether changes in NT-proBNP level are associated with changes in symptoms and left ventricular (LV) systolic function and remodeling in children with HF secondary to dilated cardiomyopathy.

METHODS

We retrospectively examined associations between serum NT-proBNP levels and NYHA/Ross functional class, LV systolic and diastolic diameter (LVSD-z and LVDD-z), LV ejection fraction (LVEF), and LV shortening fraction (LVSF-z) using generalized linear mixed models. Fluctuation in functional class of subjects was also modeled using logistic regression and receiver operating characteristic (ROC) curves.

RESULTS

In 36 children (14 males), a 10-fold increase in NT-proBNP serum levels was associated (P < .001) with a 9.8% decrease in LVEF, a 3.25-unit drop in LVSF-z, a 1.53-unit increase in LVDD-z, a 2.64-unit increase in LVSD-z, and an increased odds of being in functional class III/IV (OR 85.5; 95% CI, 10.9 to 671.0). An NT-proBNP level greater than 1000 pg/mL identified children constantly or intermittently in functional class III-IV with 95% sensitivity and 80% specificity. The reliability of a single NT-proBNP value was 0.61, but the means for two and three NT-proBNP values were 0.76 and 0.82, respectively.

CONCLUSIONS

In children with HF, NT-proBNP is associated with cardiac symptoms and indices of LV systolic dysfunction and remodeling. NT-proBNP >1000 pg/mL identifies highly symptomatic children. Within subject serial measurements of NT-proBNP are needed for a reliable and accurate determination of disease status and/or course.

Heart transplantation for heart failure in children

Heart transplantation has become standard therapy for end-stage heart failure in children with cardiomyopathy as well as complex congenital heart disease, and has a significant effect on survival and quality of life. The indications for listing and referral for transplantation are outlined. Evaluation for heart transplantation is discussed, including full pretransplant assessment. ABO incompatible listing and HLA sensitization are discussed, and listing algorithms are outlined for different countries.

BNP Levels Predict Outcome in Pediatric Heart Failure Patients

Background—

The ability of serum B-type natriuretic peptide levels (BNP) to predict outcomes in children with heart failure (HF) has not been well demonstrated. This study was designed to determine whether BNP levels predict outcomes in patients with moderate symptomatic HF.

Methods and Results—

We investigated whether enrollment BNP levels for the Pediatric Carvedilol Trial were associated with baseline characteristics. Freedom from a composite end point of HF hospitalization, death, or transplantation at 9 months was compared using a threshold BNP level identified using receiver operating curve analysis. Median BNP level was 110 pg/mL (interquartile range, 22.4 to 342.0 pg/mL) in 138 subjects. Median age was 3.4 years (interquartile range, 1.1 to 11.0 years). Diagnoses were cardiomyopathy (60%) and congenital heart disease (40%); 73% had a systemic left ventricle. BNP levels correlated moderately with left ventricular ejection fraction ( R =0.39, P <0.001) but did not differ by HF class, age, diagnosis, sex, ventricular morphology, or left ventricular end-diastolic dimension Z -score ( R =0.19). Outcome events included 25 HF hospitalizations, 4 deaths, and 2 transplants. Sensitivity was 71% and specificity 63%, for a BNP cutoff value of 140 pg/mL. BNP ≥140 pg/mL (hazard ratio, 3.7; 95% confidence interval, 1.62 to 8.4; P =0.002) and age >2 years (hazard ratio, 4.45; 95% confidence interval, 1.68 to 12.04; P =0.003) were independently associated with worse outcomes.

Conclusions—

In children with moderately symptomatic HF, BNP ≥140 pg/mL and age >2 years identified subjects at higher risk for worse outcome. Further validation is needed to determine the BNP levels necessary to stratify risk in other pediatric cohorts.

Long-term prognostic value of cardiac autonomic nervous activity in postoperative patients with congenital heart disease

BACKGROUND

Abnormal cardiac autonomic nervous activity (CANA) is not uncommon in postoperative patients with congenital heart disease (CHD).

METHODS AND RESULTS

We attempted to clarify the prognostic value of the CANA variables in postoperative CHD patients and prospectively evaluated the CANA variables in 292 consecutive biventricular and 91 Fontan repair patients. The CANA variables included the heart rate variability, arterial baroreflex sensitivity (BRS), washout ratio of the myocardial metaiodobenzylguanidine scintigraphy, and plasma norepinephrine level. With a follow-up of 10 ± 2 years, 98 total events that required hospitalization, including 13 deaths and 48 unscheduled cardiac events (UCEs), occurred. In all the CHD patients, all the CANA indices predicted the total events and UCEs. Of those, the NE level (p=0.0004) and BRS (p=0.0373) predicted the mortality. In a multivariate analysis, the BRS was an independent CANA-predictor for the total events (p=0.007). In the biventricular patients, the plasma NE level, heart rate variability, and BRS predicted the total events and UCEs and the BRS was the only independent CANA-predictor for the total events (p=0.0329). In the Fontan patients, the plasma NE level was the only predictor for the UCEs (p=0.0242) and no other CANA variables were independent predictors of the total events or UCEs.

CONCLUSIONS

All CANA variables, especially the BRS, were useful predictors for future clinical events in biventricular CHD patients, whereas no CANA variables, except for the plasma NE level, predicted future clinical events in the Fontan patients.

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.

Serum parameters and echocardiographic predictors of death or need for transplant in newborns, children, and young adults with heart failure

For children admitted with symptomatic heart failure (HF), the risk of death/need for transplantation (D/Tx) is high. Data from adult studies suggest serum measurements, such as percent lymphocytes, are valuable predictors of outcomes. The aim of this study was to identify risk factors for D/Tx in hospitalized pediatric patients with symptomatic HF. Retrospective analysis of children admitted to an academic center from January 1994 to June 2008 with clinical HF was undertaken. The most common cause of HF was dilated cardiomyopathy (58 of 99, 59%). Echocardiographic and serum measurements were collected from admission. Factors independently associated with risk of D/Tx were evaluated by a stepwise multivariate Cox regression model. There were 99 children with 139 hospitalizations. Median age at admission was 3 years (range 0 to 22). Mean systemic ventricular ejection fraction was 23% +/- 11. Risk of D/Tx per hospitalization was 60 of 139 (43%). In multivariate analysis, lymphocytopenia, lower ejection fraction, low serum sodium, and higher serum creatinine were independent predictors of D/Tx. These variables correctly predicted those subjects at risk of D/Tx in 82.1% of cases. Subgroup analysis found that brain natruretic peptide did not improve the model's accuracy markedly. In conclusion, serum measurements (percent lymphocytes, sodium, and creatinine) and echocardiographic assessment routinely obtained at admission are predictive of D/Tx in children hospitalized for HF. Significant lymphocytopenia was predictive of adverse outcomes.

Clinical course and risk profile in adolescents with idiopathic dilated cardiomyopathy

We sought to analyze the prevalence, clinical course, and risk profile of left ventricular systolic dysfunction in adolescents with idiopathic dilated cardiomyopathy. Patients with clinical onset at <13 years (n = 18) or >19 years (n = 14) of age and/or patients followed up for <12 months were excluded. Clinical and biochemical markers were evaluated during 4 +/- 3 years of follow-up to determinate predictors of adverse outcome. A composite end point (hospitalization for worsening heart failure, cardiac transplantation, and death) was investigated. The final cohort consisted of 48 patients (median age 17 years) with idiopathic dilated cardiomyopathy. During follow-up, 11 patients required hospitalization for heart failure (21%) and 6 patients entered the transplantation list (4 underwent orthotopic cardiac transplantation, 8%). A Cox multivariate model evidenced N-terminus pro-brain natriuretic peptide (NT-pro-BNP; odds ratio 1, confidence interval 1 to 1.1, p = 0.001), New York Heart Association (NYHA) classes III to IV (odds ratio 2.5, confidence interval 1 to 5.9, p = 0.04), and electrocardiographic atrial enlargement (odd ratios 6.7, confidence interval 1.8 to 25, p = 0.005) as predictors of adverse events (composite end point) at 60 months. The association of NYHA classes III to IV, electrocardiographic atrial enlargement, and NT-pro-BNP value > or =250 pg/ml (are under the curve 0.88) showed 100% sensitivity, 77% specificity, 62% positive predictive value, and 100% negative predictive value. In conclusion, compared to other clinical, echocardiographic, and biochemical parameters, the combination of advanced NYHA class, electrocardiographic atrial enlargement, and NT-pro-BNP > or =250 pg/ml seem to better predict the risk of adverse events in adolescent with long-term systolic dysfunction.

Dilated cardiomyopathy

Dilated cardiomyopathy is characterised by left ventricular dilation that is associated with systolic dysfunction. Diastolic dysfunction and impaired right ventricular function can develop. Affected individuals are at risk of left or right ventricular failure, or both. Heart failure symptoms can be exercise-induced or persistent at rest. Many patients are asymptomatic. Chronically treated patients sometimes present acutely with decompensated heart failure. Other life-threatening risks are ventricular arrhythmias and atrioventricular block, syncope, and sudden death. Genetic inheritance arises in 30-48% of patients, and inflammatory disorders such as myocarditis or toxic effects from medications, alcohol, or illicit drugs also result in dilated cardiomyopathy. Genes that cause dilated cardiomyopathy generally encode cytoskeletal and sarcomeric (contractile apparatus) proteins, although disturbance of calcium homeostasis also seems to be important. In children, disrupted mitochondrial function and metabolic abnormalities have a causal role. Treatments focus on improvement of cardiac efficiency and reduction of mechanical stress. Arrhythmia therapy and prevention of sudden death continue to be mainstays of treatment. Despite progress over the past 10 years, outcomes need to be improved.

Clinical and functional characterisation of rheumatic mitral regurgitation in children and adolescents including the brain natriuretic peptide

Rheumatic fever is a public health problem of universal distribution, predominantly affecting individuals in developing countries. In individuals less than 20 years of age, pure mitral regurgitation is the most commonly found condition in chronic rheumatic valve disease. In the present study, rheumatic mitral regurgitation was assessed in children and adolescents, addressing its clinical (duration of the disease, symptoms, use of benzathine penicillin, and number of outbreaks of the acute phase of rheumatic fever), electrocardiographic (left atrium abnormality and/or left ventricle hypertrophy) and echocardiographic characteristics (left atrium and ventricle measurements, ejection fraction and pulmonary artery pressure), as well as plasma dose of N-terminal portion of the brain natriuretic peptide through electrochemiluminescence immunoassay. Fifty-three patients were studied. The patients had moderate (41.5%) or severe (58.5%) rheumatic mitral regurgitation; had not undergone surgery; were not in the acute phase of the disease; and were being treated at a paediatric cardiology reference hospital in Northeastern Brazil. Mean patient age was 10.6 years (minimum of 3 and maximum of 19 years). With the exception of the ejection fraction, the echocardiographic variables had a significant correlation to the natriuretic peptide, demonstrating that this hormone reflects the haemodynamic consequences of mitral regurgitation. It was concluded that cardiac remodelling that occurs in rheumatic mitral regurgitation in children and adolescents leads to the production of the brain natriuretic peptide, which could be used as a complementary diagnostic tool in the follow-up of such patients.

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.

Acute heart failure syndromes in the pediatric emergency department

OBJECTIVE

The objectives of this study were to (1) describe the clinical presentation of acute heart failure syndromes (AHFS) in the pediatric emergency department (ED) and (2) determine the physician treatment regimens and outcomes in the same population.

METHODS

This was a cross-sectional study of patients who presented with AHFS to the ED at our institution from January 2003 to October 2006. We defined AHFS as "the gradual or rapid deterioration in heart failure signs and symptoms resulting in a need for urgent therapy." Patients were included when they had documented signs or symptoms of HF attributable to ventricular dysfunction. Patients were excluded when they were older than 21 years or had HF symptoms that were attributable to left-to-right intracardiac shunting or left-sided obstructive lesions. All eligible ED patient visits were adjudicated by a pediatric HF specialist.

RESULTS

Fifty-seven patient visits to the ED met inclusion criteria. There was a significant difference in time from arrival to treatment with a diuretic when the therapy was started in the ED rather than in the inpatient units. Median time to initiation of a vasoactive agent was significantly less for patients whose infusions were started in the ED compared with the ICU. Two patients died in the ED, and overall mortality or need for mechanical circulatory support for hospitalized patients was 18% (n = 10).

CONCLUSIONS

These data yield important insight into the clinical features and initial treatment of children who present with AHFS in the ED and may allow for improved recognition and treatment of this clinical syndrome.

Accuracy of plasma B-type natriuretic peptide to diagnose significant cardiovascular disease in children: the Better Not Pout Children! Study

OBJECTIVES

The purpose of this study was to assess the ability of plasma B-type natriuretic peptide (BNP) to diagnose significant cardiovascular disease (CVD) in the pediatric population.

BACKGROUND

BNP has been shown to be reliable in detecting ventricular dysfunction and heart failure in adults. Timely and accurate identification of significant pediatric heart disease is important but challenging. A simple blood test could aid the front-line physician in this task.

METHODS

Subjects without a history of heart disease with findings possibly attributable to significant CVD in the acute care setting requiring a cardiology consult were enrolled. Clinicians were blinded to the BNP result, and confirmation of disease was made by cardiology consultation.

RESULTS

Subjects were divided into a neonatal (n = 42, 0 to 7 days) and older age group (n = 58, >7 days to 19 years). CVD was present in 74% of neonates and 53% of the older age group. In neonates with disease, median BNP was 526 pg/ml versus 96 pg/ml (p < 0.001) for those without disease. In older children with disease, median BNP was 122 pg/ml versus 22 pg/ml in those without disease (p < 0.001). Subjects with disease from an anatomic defect, a longer hospital stay, or who died had higher BNP. A BNP of 170 pg/ml yielded a sensitivity of 94% and specificity of 73% in the neonatal group and 87% and 70% in the older age group, respectively, using a BNP of 41 pg/ml.

CONCLUSIONS

BNP is a reliable test to diagnose significant structural or functional CVD in children. Optimal cutoff values are different from adult values.