Secretion of A-type and B-type natriuretic peptides into the bloodstream and pericardial space in children with congenital heart disease

Postoperative B-type natriuretic peptide monitoring for the assessment of the magnitude of shunting through Blalock-Taussig anastomoses

BACKGROUND

The Modified Blalock-Taussig shunt (MBTS) is the most common palliative operation performed in patients with complex cardiac defects. Postoperative morbidity and mortality rates are high, mainly due to shunt thrombosis and over-shunting. Over-shunting may be difficult to identify postoperatively based on conventional criteria. Since plasma B-type natriuretic peptide (BNP) concentrations correlate with the magnitude of shunting in various left-to-right shunt cardiac defects, we investigated its ability to identify postoperative MBTS over-shunting.

METHODS AND RESULTS

This retrospective, observational study included 42 consecutive patients (median age 9.50days, IQR: 6.00-58.25) undergoing MBTS for obstruction of the pulmonary blood flow at a tertiary referral pediatric cardiac center. The BNP threshold concentrations which accurately predicted outcome and MBTS over-shunting were derived using the ROC methodology. 443 BNP concentrations were analysed. The presence of atrio-ventricular valve regurgitation was the most important component of overall variance (72.75%). In 34 patients without regurgitation, BNP concentrations were predictive of a duration of mechanical ventilation >8days and of intensive care stay >11days, with ROC areas of 0.655 [0.597-0.719], 0.650 [0.589-0.711], a negative predictive value for the >1035pgmL^-1 threshold of 0.93 and 0.96 respectively. SaO₂ was less accurate for the prediction of both outcomes. In patients in whom the pulmonary flow was entirely MBTS-supplied, a BNP concentrations >1052pgmL^-1 was predictive of a pulmonary-to-systemic ratio>2.

CONCLUSION

In MBTS patients without atrio-ventricular valve regurgitation, maintaining BNP below 1000pgmL^-1 may represent a therapeutic target to avoid over-shunting.

Changes in Plasma Atrial and Brain Natriuretic Peptide Levels in Children Undergoing Surgical Isolated Atrial Septal Defect Closure

Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels increase after cardiopulmonary bypass (CPB) in pediatric patients. However, the exact reason for the postoperative increase remains unclear. This study elucidated the perioperative changes in plasma natriuretic peptide levels in children undergoing surgical isolated atrial septal defect (ASD) closure. Between 2010 and 2012, 24 pediatric patients (median 7.1, range 2.7-15.7 years) underwent surgery for simple ASD using CPB under ventricular fibrillation (Group A, 16 patients) or under cardiac arrest (Group B, 8 patients). Natriuretic peptide levels were measured before surgery, on postoperative day 0, 1, 3, and at the first outpatient visit. The pulmonary to systemic blood flow ratio (Qp/Qs) was estimated by echocardiography using an index of right ventricle end-diastolic area. Preoperative natriuretic peptide levels positively correlated with the Qp/Qs. Plasma ANP levels peaked on postoperative day 0, and its values were higher in Group A than in Group B patients (p < 0.001). Plasma BNP levels increased significantly in both Groups on postoperative day 1, and its values were significantly greater in Group A than in Group B patients (p = 0.007). There was a weak negative correlation between the amount of postoperative increase in natriuretic peptide levels and the Qp/Qs. There was no appreciable difference in the acute postoperative clinical course and echocardiographic parameter on postoperative day 3 between Group A and B patients. In conclusion, acute postoperative natriuretic peptide levels after isolated ASD closure were multifactorial, and they might be unreliable for predicting clinical outcomes.

Changes in serum natriuretic peptide levels after percutaneous closure of small to moderate ventricular septal defects

Background. B-type natriuretic peptide has been shown to be a very sensitive and specific marker of heart failure. In this study, we aimed to investigate the effect of percutaneous closure of ventricular septal defects with Amplatzer septal occluders on brain natriuretic peptide levels. Methods. Between 2008 and 2011, 23 patients underwent successfully percutaneous ventricular septal defect closure in 4 cardiology centers. Brain natriuretic peptide levels were measured in nine patients (4 male, mean ages were 25.3 ± 14.3) who underwent percutaneous closure with Amplatzer occluders for membranous or muscular ventricular septal defects were enrolled in the study. Brain natriuretic peptide levels were measured one day before and one month after the closure. Patients were evaluated clinically and by echocardiography one month after the procedure. Results. Percutaneous closures of ventricular septal defects were successfully performed in all patients. There was not any significant adverse event in patients group during followup. Decrease in brain natriuretic peptide levels after closure were statistically significant (97.3 ± 78.6 versus 26.8 ± 15.6, P = 0.013). Conclusion. Brain Natriuretic Peptide levels are elevated in patients with ventricular septal defects as compared to controls. Percutaneous closure of Ventricular Septal Defect with Amplatzer occluders decreases the BNP levels.

Early N-terminal pro-brain natriuretic peptide measurements predict clinically significant ductus arteriosus in preterm infants

We report a blinded, prospective study of the diagnostic utility of N-terminal pro-brain natriuretic peptide (NTproBNP) measurements for predicting clinically significant patent ductus arteriosus (PDA) and assessing closure.

METHODS

Plasma NTproBNP was measured during the first week in 100 preterm babies (mean gestation 28.8 +/- 2.9 weeks; mean birth weight 1224 +/- 512 g). Echocardiography was performed between days 5 and 7 by operators, blinded to NTproBNP concentration.

RESULTS

NTproBNP peaked on days 2 and 3, declined by day 7. Twenty babies, later treated for PDA, had significantly higher NTproBNP levels throughout. Areas under receiver operating characteristic (ROC) curves were 0.896, 0.897 and 0.931 on days 2, 3 and 7, respectively (p < 0.0001). A concentration > 2850 pmol/L had diagnostic sensitivity of 90% and specificity of 89% (95% CI: 68, 99; likelihood ratio 8.10). Ductal closure was associated with a fall in mean NTproBNP from 3003 to 839 pmol/L (p < 0.001).

CONCLUSION

N-terminal pro B-type brain natriuretic peptide (NTproBNP) concentrations peaked and then declined in the first week but remained higher in preterm babies whose PDA required treatment. NTproBNP on day 3 predicted whether a neonatal physician blinded to results would treat a PDA. Fall in plasma NTproBNP indicated closure.

Brain natriuretic peptide concentration in pericardial fluid is independently associated with atrial fibrillation after off-pump coronary artery bypass surgery

OBJECTIVES

Postoperative atrial fibrillation is associated with the increased incidence of morbidities and mortality. Predisposing determinants of atrial fibrillation development after off-pump coronary artery bypass grafting remain unclear. We hypothesized that pericardial fluid natriuretic peptide concentrations have a predictive value for developing postoperative atrial fibrillation in patients who have undergone off-pump coronary artery bypass grafting.

METHODS

We prospectively measured atrial natriuretic peptide and brain natriuretic peptide concentrations in plasma and pericardial fluid in 42 consecutive patients undergoing off-pump coronary artery bypass grafting, then continuously observed the occurrence of atrial fibrillation following off-pump coronary artery bypass grafting until the time of discharge.

RESULTS

Postoperative atrial fibrillation was documented in nine patients (21%, atrial fibrillation group), and not in 33 patients (no atrial fibrillation group). Between the groups, there was neither significant difference in plasma atrial natriuretic peptide concentrations nor in pericardial atrial natriuretic peptide concentrations. Plasma brain natriuretic peptide concentrations were comparable in both groups [56.2 (interquartile range 42.7-102.8) vs. 35.2 pg/ml (13.8-75.0), P=0.07]. Pericardial fluid brain natriuretic peptide concentrations were significantly higher in the atrial fibrillation group than in the no atrial fibrillation group [188.0 (124.8-411.0) vs. 39.3 pg/ml (10.0-88.4), P=0.0001]. In a multivariable logistic regression model, pericardial brain natriuretic peptide concentration was significantly associated with a higher risk of postoperative atrial fibrillation (odds ratio=3.0 every 50 pg/ml increase; 95% confidence interval, 1.1-8.6; P=0.04).

CONCLUSION

Our results suggested that pericardial fluid brain natriuretic peptide concentration is independently associated with the development of atrial fibrillation after off-pump coronary artery bypass grafting.

Relationship between Pericardial Fluid B-type Natriuretic Peptide and Ventricular Structure and Function

BACKGROUND

We undertook this study to investigate the levels of pericardial B-type natriuretic peptide (BNP) and its relationship with ventricular structure and function.

METHODS

Pericardial and plasma BNP concentrations were measured in 18 patients with congenital ventricular septal defect.

RESULTS

The mean level of BNP in the pericardial fluid (324.8+/-137.3 pg/mL) was higher than the plasma (20.8+/-6.1 pg/mL) (p=0.03). Pericardial BNP was correlated with the plasma BNP (r=0.85, p<0.01). A good correlation was also found between the pericardial BNP and left atrial diameter, left ventricular end-diastolic and end-systolic diameter, left ventricular ejection fraction, right ventricular diameter and pulmonary artery systolic pressure (p<0.05).

CONCLUSIONS

The levels of BNP in pericardial fluid were higher than in the plasma. Similar to plasma BNP, pericardial BNP is also related to the ventricular structure and function.

Utility of rapid B-type natriuretic peptide assay for diagnosis of symptomatic patent ductus arteriosus in preterm infants

OBJECTIVE

In preterm infants, the rapid and accurate determination of the presence of a hemodynamically significant patent ductus arteriosus (PDA) is extremely important, but this is often difficult. Plasma B-type natriuretic peptide (BNP) measurement has been reported to be a helpful aid in the diagnosis of hemodynamically significant PDA in preterm infants. The aim of our study was to investigate the usefulness of a rapid BNP assay as a diagnostic marker of symptomatic PDA (sPDA) in preterm infants.

METHODS

Sixty-six preterm infants, ranging from 25 to 34 gestational weeks of age, underwent clinical and echocardiographic examinations for PDA every other day from the third day of life until the disappearance of ductal flow. Blood samples were collected and plasma BNP concentrations were measured simultaneously using a commercial kit, (Triage BNP test kit; Biosite Diagnositics, San Diego, CA). When > or =2 clinically significant features of PDA were noted, and a large ductal flow was confirmed by color Doppler echocardiography, sPDA was diagnosed and treated with indomethacin.

RESULTS

On the third day after birth, the mean BNP concentration in the sPDA group (n = 23) was significantly higher than in the control group (n = 43) (2896 +/- 1627 vs 208 +/- 313 pg/mL). Seventeen infants (74%) in the sPDA group became asymptomatic after an initial course of indomethacin and their BNP levels concomitantly decreased. Moreover, BNP concentrations were significantly correlated with the magnitudes of the ductal shunt, such as the ratio of left atrial to aortic root diameter and the diastolic flow velocity of the left pulmonary artery (r = 0.726 and 0.877). The area under the receiver operator characteristic curve for the detection of sPDA was high: 0.997 (95% confidence interval: 0.991-1.004). The best cutoff of BNP concentration for the diagnosis of sPDA was determined to be 1110 pg/mL (sensitivity: 100%; specificity: 95.3%).

CONCLUSION

In preterm infants, the circulating BNP levels correlated well with the clinical and echocardiographic assessments of PDA. Although not a stand-alone test, the rapid BNP assay provides valuable information for the detection of infants with sPDA that require treatment. Moreover, serial BNP measurements may be of value in determining the clinical course of PDA in preterm infants.