Multicenter analytical performance evaluation of the Elecsys® proBNP assay

Increased left atrial volume index is an independent predictor of raised serum natriuretic peptide in patients with suspected heart failure but normal left ventricular ejection fraction: Implication for diagnosis of diastolic heart failure

BACKGROUND

Left atrial volume index (LAVI) is increasingly recognised as a relatively load-independent marker of left ventricular (LV) filling pressures. We assessed the capacity of LAVI to predict LV diastolic dysfunction in comparison with N-terminal pro B-type natriuretic peptide (NTproBNP) in patients with suspected heart failure and a normal ejection fraction (EF).

METHODS

137 patients with suspected heart failure (HF), referred from the community for echocardiography, prospectively underwent Doppler echocardiography, LAVI and NTproBNP estimation. Raised LAVI and reduced LV systolic function were defined as >26 ml/m2 and LV EF <50% respectively.

RESULTS

Of 137 patients, 21 were excluded (2 with significant mitral valve disease and 19 with atrial fibrillation). Of the remaining 116 subjects, 92 showed normal LV systolic function. The univariate predictors of serum log NTproBNP were age (p < 0.001), LA dimension (p = 0.001), LAVI (p < 0.001), A wave (p = 0.001), E:A (p = 0.07) and septal wall thickness (p = 0.004). However on multivariate analysis, LAVI was found to be the most consistent and significant predictor of NTproBNP. The area under the curve of the receiver operating characteristic (ROC) curve for NTproBNP in detecting patients with LVEF > or = 50% and LAVI >26 ml/m2 was 0.81 (p < 0.0001) and for patients with LAVI > 26 ml/m2 with and without LVEF > or = 50% was 0.82 (p < 0.0001).

CONCLUSION

This data confirms that LAVI on resting echocardiography, specifically in patients with suspected HF and normal LV systolic function is a powerful independent predictor of LV diastolic dysfunction as predicted by serum NTproBNP. In a population with a high suspicion of diastolic heart failure, LAVI may significantly contribute to diagnostic precision.

Assessment of BNP and NT-proBNP in emergency department patients presenting with suspected acute coronary syndromes

OBJECTIVES

The relationship between BNP and NT-proBNP among physiologically and clinically relevant demographic subgroups has never been clarified in the context of the emergency department (ED).

DESIGN AND METHODS

A blood sample taken from patients presenting to the E.D. with suspected acute coronary syndromes (ACS) was analyzed for BNP and NT-proBNP, and correlation between them was examined as an entire group then as subgroups according to gender, ethnicity, age, and comorbidity variables.

RESULTS

BNP and NT-proBNP correlate well (0.89, P < 0.0001) in a population of 420 patients and in patient subgroups with a history of various etiologies, including vascular disorders.

CONCLUSIONS

In general, BNP and NT-proBNP correlate very well in patients with suspected ACS and may aid in the risk stratification process in emergency departments.

NT-ProBNP in Acute Heart Failure: Correlation With Invasively Measured Hemodynamic Parameters During Recompensation

BACKGROUND

N-terminal brain natriuretic peptide (NT-proBNP) level is elevated in patients with acute and chronic heart failure. This study addresses whether NT-proBNP correlates with invasively measured hemodynamic parameters and whether a decrease of NT-proBNP over time correlates with invasively monitored hemodynamic improvement.

METHODS AND RESULTS

Twenty consecutive patients with acute exacerbation of chronic heart failure (New York Heart Association class III-IV) were included in this prospective study. NT-proBNP and hemodynamic measurements by balloon-tipped pulmonary artery catheter were performed simultaneously. Recompensation strategies included vasodilators, diuretics, and inotropes. The patients were divided in 2 subgroups. Group A, by definition, had a hemodynamic improvement over 24 hours with an increase of cardiac index of >30% and a decrease of pulmonary capillary wedge pressure of >30%. Group B did not show a hemodynamic improvement. Group A had a decline of NT-proBNP levels to 42% of the baseline value over 32 hours. In group B, the NT-pro BNP levels did not change significantly over 32 hours.

CONCLUSION

The decrease of NT-proBNP correlates with hemodynamic improvement in patients with decompensated heart failure. The relative changes of NT-proBNP seem to be a reliable diagnostic tool in monitoring these patients. There results have been confirmed in a larger patient group.

Elecsys NT-ProBNP and BNP Assays: Are There Analytically and Clinically Relevant Differences?

BACKGROUND

B-type natriuretic peptide (BNP; 77-108 amino acids) and its N-terminal (1-76 amino acids) counterpart, NT-proBNP, are cardiac biomarkers that have been established for the assessment of left ventricular dysfunction and congestive heart failure and provide prognostic and risk stratification information for patients with acute coronary syndrome. Various automated immunoassays currently are available for the measurement of these natriuretic peptides, but there are significant analytical differences, especially between BNP and NT-proBNP.

METHODS AND RESULTS

Recently published methods and results were reviewed.

CONCLUSION

Although there are significant pre-analytical and analytical differences between the Triage BNP and Elecsys NT-proBNP and other BNP methods, they do not translate to clinically significant differences in their diagnostic and prognostic application in the assessment of systolic heart failure and risk stratification of patients with acute coronary syndrome. However, there appears to be some evidence that suggests that NT-proBNP may have an advantage in the detection of patients with mild or asymptomatic heart disease.

Plasma levels of N-terminal pro-brain natriuretic peptide in patients with coronary artery disease and relation to clinical presentation, angiographic severity, and left ventricular ejection fraction

Comparative assessment of N-terminal pro-brain natriuretic peptide (NT-pro-BNP) across a wide spectrum of angiographic and clinical coronary artery disease (CAD) in a consecutive series of patients has not been reported. This study examined 879 subjects (684 patients who had angiographically proved CAD and 195 controls who did not have CAD). NT-pro-BNP concentrations were measured before an angiographic procedure that allowed diagnosis of CAD and measurements of left ventricular ejection fraction and end-diastolic blood pressure. Median values (25th and 75th percentiles) of NT-pro-BNP in patients and controls were 474.5 pg/ml (162.3 and 1,542.8) and 117.0 pg/ml (60.1 and 230.6), respectively (p <0.001). In patients who had stable angina, unstable angina, and acute myocardial infarction, NT-pro-BNP concentrations were 327.7 pg/ml (129.2 and 973.2), 660.6 pg/ml (201.2 and 1,563.5), and 1,045.0 pg/ml (323.8 and 2,486.0, p <0.001). NT-pro-BNP concentrations in subgroups with 1-, 2-, and 3-vessel CAD were 385.5 pg/ml (117.2 and 1,266.0), 463.0 pg/ml (135.0 and 1,480.5), and 533.8 pg/ml (221.8 and 1,809.4), respectively (p = 0.005). Multivariable analysis showed that NT-pro-BNP was an independent correlate of the presence of CAD (chi-square 10.8, odds ratio 1.08, 95% confidence interval 1.03 to 1.13 for 100-pg/ml increase in concentration; p <0.001), acute coronary syndromes (chi-square 6.3, odds ratio 1.01, 95% confidence interval 1.00 to 1.02 for 100-pg/ml increase in concentration, p = 0.01) and a strong trend that was independently associated with angiographic severity (chi-square 3.68, p = 0.055). This study shows that NT-pro-BNP concentrations are high across the entire spectrum of CAD and parallel the clinical or angiographic severity of CAD.

Analytical evaluation of the Dade Behring Dimension RxL automated N-Terminal proBNP (NT-proBNP) method and comparison with the Roche Elecsys 2010

Methods to quantify B-type natriuretic peptide (BNP) and N-terminal-propeptide (NT-proBNP) in plasma or serum samples are well established. We assessed the analytical performance of the Dimension RxL NT-proBNP method (Dade-Behring). Evaluation of different sample types was carried out. Controls and heparin plasma pools were used to determine the detection limit, precision, and linearity. Sample stability and the effect of interfering substances on the NT-proBNP concentrations were evaluated. Agreement between Dimension RxL and Elecsys 2010 (Roche Diagnostics) NT-proBNP methods was assessed. The influence of age and sex on NT-proBNP concentrations was evaluated in healthy subjects. Heparin plasma should be the matrix of choice. The detection limit was 2.0ng/L. The total imprecision was 2.6–3.6% for concentrations from 231 to 9471ng/L; mean NT-proBNP concentrations of 21 and 15ng/L were associated with coefficients of variation of 9.9% and 14.7%, respectively. The method was linear up to 32,650ng/L. There was no effect of temperature, freeze-thaw cycles and interfering substances. A bias was detected when Dimension RxL and Elecsys 2010 NT-proBNP methods were compared. Age and sex were significantly and independently related to NT-proBNP concentrations. The Dimension RxL NT-proBNP method, like the Elecsys 2010, is suitable for routine use in the diagnosis of heart failure.