Thomas S. Mir

NT-Pro-B-type Natriuretic Peptide in Infants and Children: Reference Values Based on Combined Data from Four Studies

In cardiology, B-type natriuretic peptide and the amino terminal segment of its prohormone (NT-proBNP) are important biomarkers. The importance of these peptides as markers for heart disease in pediatric cardiology is reviewed. The peptide levels are dependent on age, assay, and possibly gender. The normal value range and upper limits for infants and children are needed. To determine reference values, data were combined from four studies that measured NT-proBNP levels in normal infants and children using the same electrochemiluminescence assay. The age intervals for the upper limits of normal were chosen for intervals in which no age-dependent change was observed. Statistical analysis was performed on log-transformed data. A total of 690 subjects (47% males) ages birth to 18xa0years were included in the review. The levels of NT-proBNP were highest in the first days of life, then showed a marked decline in the first week or weeks. The peptide levels continued to decline gradually with age (rxa0=xa00.43; pxa0<xa00.001). Male and female levels differed only for children ages 10 to 14xa0years. However, the upper limit of normal did not differ between the boys and girls in any age group. The findings lead to the conclusion that B-type natriuretic peptide (BNP) and NT-proBNP are important markers for heart disease in pediatric cardiology. The levels of NT-proBNP are highest in the first days of life and decrease drastically thereafter. A mild gradual decline occurs with age throughout childhood. Girls have somewhat higher levels of NT-proBNP during puberty.

N-Terminal pro-brain natriuretic peptide: normal ranges in the pediatric population including method comparison and interlaboratory variability

Abstract The aim of the present study was the investigation of N-terminal pro-brain natriuretic peptide (NT-proBNP) in the pediatric population. This is essential for adequate monitoring and classification of pediatric patients with heart disease, but no consistent data are available yet. In addition, the comparability of two commercially available NT-proBNP assays and the inter-laboratory variability for the most suitable one were assessed. For this purpose, 408 subjects (1–29years) were included. NT-proBNP was determined with a non-competitive electrochemiluminescent immunoassay (Roche NT-proBNP; n=402) and a competitive enzyme-immunoassay (Biomedica NT-proBNP; n=402). Inter-laboratory variability was evaluated for the Roche assay by stepwise inclusion of four and 11 centers throughout Germany, respectively. Roche NT-proBNP ranged from 5.0 to 391.5ng/L, with higher values for younger children. The 97.5th (75th) percentile curve ranged from 319.9ng/L (231.2 ng/L, 1–3years) to 114.9ng/L (53.3 ng/L, 18years). In contrast, Biomedica NT-proBNP ranged from 253.7 to 7602.8 ng/L, with no significant age dependency. The mean difference between the assays was 1649.7ng/L (95% confidence interval 1546.3–1753.1ng/L). Inter-laboratory variability ranged from 6.5% to 3.8%, covering a range from 51.3 to 6618.1ng/L. The assay seems to influence the interpretation of resulting NT-proBNP values and therefore has to be chosen carefully. For the monitoring and classification of pediatric patients with congenital heart disease, age-based NT-proBNP values should be used.

Plasma Concentrations of N-Terminal Brain Natriuretic Peptide in Healthy Children, Adolescents, and Young Adults: Effect of Age and Gender

Children with congenital heart disease need adequate diagnostic classification regarding their cardiovascular status (CVS). N-terminal brain natriuretic peptide (N-BNP) plasma concentration indicates dysfunction of the cardiovascular system and guides decisions concerning treatment and prognosis. Reference values are established for adults, with age-dependent increasing values and higher values in women. To avoid misclassification concerning the CVS, a large group of healthy children and adolescents can be used show the relationship between gender, age, and N-BNP and these can serve as reference values. N-BNP was measured in 434 healthy subjects (240 female and 194 male) with ages ranging from 0 to 32 years without any cardiovascular disease or renal or hepatic impairment. Measurements were performed with an electrochemiluminescence immunoassay from Roche Diagnostics. Mean N-BNP decreased from 12.6 fmol/ml (0–9 years; n = 79) to 9.41 fmol/ml (10–14 years; n = 154) and in adolescents from 6.1 (15–19 years; n = 99) to 4.8 fmol/ml (>19 years; n = 102) in adults (p < 0.05). Mean N-BNP concerning gender did not differ in any age group younger than 19 years. In contrast, the adult female group had 78% higher N-BNP compared to the male group (p < 0.05). There was a significant peak in N-BNP at the age of 12–14 years. This study shows that reference values for N-BNP differed profoundly in children compared to adults and were up to 260% higher in children without any gender difference. Therefore, these reference values will help to avoid CVS misclassification in children for the biomarker N-BNP.

Levels of brain natriuretic peptide in children with right ventricular overload due to congenital cardiac disease.

OBJECTIVEnTo evaluate the role of the concentration of brain natriuretic peptide in the plasma, and its correlation with haemodynamic right ventricular parameters, in children with overload of the right ventricle due to congenital cardiac disease.nnnMETHODSnWe studied 31 children, with a mean age of 4.8 years, with volume or pressure overload of the right ventricle caused by congenital cardiac disease. Of the patients, 19 had undergone surgical biventricular correction of tetralogy of Fallot, 11 with pulmonary stenosis and 8 with pulmonary atresia, and 12 patients were studied prior to operations, 7 with atrial septal defects and 5 with anomalous pulmonary venous connections. We measured brain natriuretic peptide using Triage(R), from Biosite, United States of America. We determined end-diastolic pressures of the right ventricle, and the peak ratio of right to left ventricular pressures, by cardiac catheterization and correlated them with concentrations of brain natriuretic peptide in the plasma.nnnRESULTSnThe mean concentrations of brain natriuretic peptide were 87.7, with a range from 5 to 316, picograms per millilitre. Mean end-diastolic pressure in the right ventricle was 5.6, with a range from 2 to 10, millimetres of mercury, and the mean ratio of right to left ventricular pressure was 0.56, with a range from 0.24 to 1.03. There was a positive correlation between the concentrations of brain natriuretic peptide and the ratio of right to left ventricular pressure (r equal to 0.7844, p less than 0.0001) in all patients. These positive correlations remained when the children with tetralogy of Fallot, and those with atrial septal defects or anomalous pulmonary venous connection, were analysed as separate groups. We also found a weak correlation was shown between end-diastolic right ventricular pressure and concentrations of brain natriuretic peptide in the plasma (r equal to 0.5947, p equal to 0.0004).nnnCONCLUSIONnThere is a significant correlation between right ventricular haemodynamic parameters and concentrations of brain natriuretic peptide in the plasma of children with right ventricular overload due to different types of congenital cardiac disease. The monitoring of brain natriuretic peptide may provide a non-invasive and safe quantitative follow up of the right ventricular pressure and volume overload in these patients.

Utility of N-terminal brain natriuretic peptide plasma concentrations in comparison to lactate and troponin in children with congenital heart disease following open-heart surgery

We conducted a prospective study in a pediatric cardiac intensive care unit in order to determine the diagnostic value of N-terminal brain natriuretic peptide (N-BNP) plasma concentration in the perioperative care of children with congenital heart disease (CHD). N-BNP plasma concentrations were determined by using a validated enzyme immunoassay. We measured N-BNP the day before surgery and up to 15 days postoperatively in 23 children (age range, 0.25–11 years) undergoing cardiac surgery due to various CHDs. Supply and duration of catecholamines, vasodilators, and respiratory therapy were determined and correlated to N-BNP. In addition, troponin T (TnT) and arterial Lactat (aL) concentrations were measured simultaneously. We found a significant correlation between preoperative and maximal N-BNP levels and dosage of vasodilators (r = 0.41, p < 0.02 and r = 0.83, pu2009< 0.01, respectively). Maximal TnT and aL levels were not correlated to dosage of vasodilators. The dosage and duration of catecholamines, the duration of respiratory therapy, and the plasma concentration of TnT and aL were not correlated to pre- or perioperative N-BNP. Maximal TnT and aL levels were correlated to duration (r = 0.53, p < 0.01 and r = 0.48, p < 0.02) and dosage (r = 0.52, p < 0.02 and r = 0.60, p < 0.01) of catecholamines and duration of respiratory therapy (r = 0.57, p < 0.01 and r = 0.50, p < 0.02). As recent studies show, N-BNP appears to be a powerful neurohumoral indicator of ventricular function and prognosis for guiding therapy in the outpatient department or for discriminating cardiac from noncardiac symptoms. In contrast, the value of N-BNP for guiding perioperative therapy in pediatric cardiac intensive care units is limited.

Total serum transforming growth factor-β1 is elevated in the entire spectrum of genetic aortic syndromes.

Total serum transforming growth factor‐beta 1 (tsTGF‐β1) is increased in patients with Marfan syndrome (MFS), but it has not been assessed in thoracic aortic aneurysm and dissection (TAAD), Loeys‐Dietz syndrome (LDS), and bicuspid aortic valve disease (BAVD).

Retrospective analysis of the effect of angiotensin II receptor blocker versus β-blocker on aortic root growth in paediatric patients with Marfan syndrome

Objectives Cardiovascular pathology, including aortic root dilation at the level of sinus of Valsalva (SV), is one of the major causes of morbidity in paediatric patients with Marfan syndrome (MFS). β-Blocker (BB) is well established to slow aortic dilation in MFS. Less is known about the effectiveness of angiotensin II receptor blocker (ARB) on aortic dilation in paediatric patients with MFS. Methods 215 patients with MFS (9.01±5.7u2005years) were subject to a standardised diagnostic programme. Aortic root dilation was evaluated and followed up by echocardiography. In 48 cases, BB and ARB effects on aortic root dilation were evaluated. Effect of treatment was measured by comparison of z scores of SV before and after treatment initiation. Results Treatment by ARB and BB leads to significant reduction of SV dilation (p<0.05). The deviation of SV enlargement from normal as expressed by the rate of change in z scores was significantly reduced by a mean difference of −0.56±0.71 z scores (p<0.001) under ARB therapy and by a mean difference of −0.35±0.68 z scores (p<0.05) under BB therapy. The prophylactic effect of ARB and BB on aortic root dilation is similar in both groups (p>0.05). Conclusions Both concepts lead to a significant reduction of SV dilation. The effect of ARB and BB is similar. This is the first study concerning the comparison of ARB and BB in previously untreated paediatric patients with MFS. The results of the study show that both treatment strategies are beneficial in paediatric and adolescent patients.

Impact of Age and Gender on Cardiac Pathology in Children and Adolescents With Marfan Syndrome

Abstract Cardiac pathologies are the major aspect in the treatment strategies for Marfan syndrome (MFS). In this progressive disease, less is known about manifestations and progression of cardiovascular symptoms in children. To define a certain decision regarding therapeutic options, knowledge concerning the onset of cardiovascular findings is essential. From 1998 to 2011, suspected pediatric Marfan patients were subjected to a standardized diagnostic program. Cardiovascular findings were analyzed in terms of age at first clinical manifestation, prevalence and gender differences, morbidity, mortality, and treatment. Marfan syndrome was diagnosed in 82 patients (46 boys; mean age at diagnosis, 9.0xa0±xa05.7xa0years). At first presentation, aortic root dilation was found in 56xa0% of patients, mitral valve prolapse in 31xa0%, whereas pulmonary artery dilation was detected in 22xa0% and tricuspid valve prolapse in only 17xa0% of patients. Aortic (2.5xa0%) and mitral valve regurgitations (22xa0%) are significantly correlated with aortic root dilation (pxa0<xa00.01) and mitral valve prolapse (pxa0<xa00.05) but without relevant progression during childhood. Prophylactic medication was initiated for 42xa0% of the patients (mean age, 8.0xa0±xa04.5xa0years) because of progressive aortic root dilation. Aortic dissection did not appear. Aortic root surgery was needed for 4xa0% of the patients. Gender-specific differences in cardiovascular findings, progression of disease, or treatment did not appear. Comparable with adults, aortic root dilation is the most frequent cardiovascular finding in children and associated with relevant morbidity, whereas aortic and mitral valve regurgitation are of minor clinical relevance. Manifestation at an early age and slow progression of cardiovascular findings underscore the necessity of repeated echocardiographic examinations for early diagnosis and start of prophylactic treatment.

Early Stage 2 Palliation Is Crucial in Patients With a Right-Ventricle-to-Pulmonary-Artery Conduit

BACKGROUNDnImproved survival after Norwood stage 1 palliation is giving more patients the opportunity to reach stage 2 palliation; thus, more patients are exposed to the risk of interstage death.nnnMETHODSnA single-center review of patients who underwent stage 1 palliation from January 1998 to December 2007 (n = 58) was performed. Pulmonary blood flow was established either by a modified Blalock-Taussig-shunt (mBTS, n = 33) or a right ventricle-to-pulmonary artery conduit (RVPAC, n = 25).nnnRESULTSnHospital, interstage, and 1-year survival was not significantly different between groups. However, Kaplan-Meier survival analysis reflected a significantly higher survival probability for RVPAC patients until the age of 120 days (RVAPC, 92% ± 5% [standard error of the mean]; 95% confidence interval, 82 to 100; mBTS, 63% ± 9%; 95% confidence interval, 48 to 82; p = 0.01). During a 1-year follow-up, all 11 nonsurvivors with mBTS died at an age younger than 120 days, including 2 patients with early stage 2 palliation. In contrast, besides 2 early deaths, all RVPAC patients (n = 5) showed later attrition at an age older than 120 days while awaiting stage 2 palliation. Interstage death occurred significantly later among RVPAC patients (RVPAC, 146 ± 60 days versus mBTS, 81 ± 23 days; p = 0.01). After stage 2 palliation, all patients with RVPAC survived, including 7 patients with surgery at an age younger than 120 days. All interstage and late deaths were related to compromising cardiac lesions with no statistical difference between groups.nnnCONCLUSIONSnAfter Norwood stage 1 palliation, survival was improved with RVPAC for the first 4 months. However, a loss of the favorable primary outcome was present by delaying stage 2 palliation beyond the age of 120 days. Progressive volume load as a result of conduit regurgitation may play a crucial role for later attrition. Residual lesions should be addressed early to preserve cardiac function.

The role of the multidisciplinary health care team in the management of patients with Marfan syndrome.

Marfan syndrome (MFS) is a rare, severe, chronic, life-threatening disease with multiorgan involvement that requires optimal multidisciplinary care to normalize both prognosis and quality of life. In this article, each key team member of all the medical disciplines of a multidisciplinary health care team at the Hamburg Marfan center gives a personal account of his or her contribution in the management of patients with MFS. The authors show how, with the support of health care managers, key team members organize themselves in an organizational structure to create a common meaning, to maximize therapeutic success for patients with MFS. First, we show how the initiative and collaboration of patient representatives, scientists, and physicians resulted in the foundation of Marfan centers, initially in the US and later in Germany, and how and why such centers evolved over time. Then, we elucidate the three main structural elements; a team of coordinators, core disciplines, and auxiliary disciplines of health care. Moreover, we explain how a multidisciplinary health care team integrates into many other health care structures of a university medical center, including external quality assurance; quality management system; clinical risk management; center for rare diseases; aorta center; health care teams for pregnancy, for neonates, and for rehabilitation; and in structures for patient centeredness. We provide accounts of medical goals and standards for each core discipline, including pediatricians, pediatric cardiologists, cardiologists, human geneticists, heart surgeons, vascular surgeons, vascular interventionists, orthopedic surgeons, ophthalmologists, and nurses; and of auxiliary disciplines including forensic pathologists, radiologists, rhythmologists, pulmonologists, sleep specialists, orthodontists, dentists, neurologists, obstetric surgeons, psychiatrist/psychologist, and rehabilitation specialists. We conclude that a multidisciplinary health care team is a means to maximize therapeutic success.