NT-proBNP/BNP

B-type natriuretic peptide (BNP) and N terminal-pro-B-type natriuretic peptide (NT-proBNP) are peptide hormones produced in the heart by breakdown of a precursor protein (pre-pro-BNP). BNP causes natriuresis, diuresis and vasodilation; NT-proBNP is inactive.

The use of BNP/NT-proBNP as the primary screening tool for diagnosis/exclusion of heart failure is recommended in all European and American cardiology guidelines and has also been prioritised in the Chronic Heart Failure guidelines: SIGN147 (2016) and NICE106 (2018).

Plasma BNP and NT-proBNP concentrations are raised in patients with both HF-REF and HF-PEF and the concentrations tend to rise with deteriorating NYHA class. Pooled sensitivity for the diagnosis of HF using NT-proBNP testing was 0.91 (95% CI 0.88 to 0.93) and specificity was 0.76 (95% CI 0.75 to 0.77) (SIGN 147)

Refer to local guidelines for details on availability of testing and clinical cut off values.

Natriuretic peptide (BNP-type natriuretic peptide or NT-proBNP) levels should be measuredin patients with suspected heart failureto decide if echocardiography is needed or not.

To help make this decision, thepatient should undergo anECGandmeasurement of BNP / NTpro-BNP levels(depending on local circumstances). If either test is abnormal, there is sufficient likelihood of HF to warrant echocardiography to confirm a diagnosis. If both tests are normal, HF is
unlikely and alternative tests for the symptoms should be considered.

BNP levels can predict risk of hospitalisation and mortality, people presenting with signs and symptoms of HF in the community setting and who have very high natriuretic peptide levels should
be treated more urgently than those with lower, but still abnormal, levels of natriuretic peptides.

NICE devised the following thresholds, based on the expert opinionof the group:

• BNP greater than 400pg/ml(ng/L) or NT-proBNP greater than 2,000pg/ml (ng/L):echocardiogram and specialist clinical assessment no longer than two weeks from the time of presentation.
• BNP 100pg/ml to 400pg/ml (ng/L) or NT-proBNP 400pg/ml to 2,000pg/ml (ng/L): echocardiogram and specialised clinical assessment within six weeks from the time of presentation.
• BNP less than100pg/ml(ng/L)or NT-proBNP less than 400pg/ml(ng/L)in the absence of HF therapy: HF is an unlikely cause for the presentation.

Naturetic peptides should not be used to screening the asymptomatic population.
Note: Naturetic peptides can be reduced if: BMI is greater than 35; patient is on medication for HF (e.g. diuretics, ACE inhibitors, AIIRAs, beta-blockers, aldosterone antagonists)

Naturetic peptides should not be repeated for the same symptoms unless in exceptional circumstances, e.g. intervening MI.

1. Scottish Intercollegiate Guidelines Network (SIGN). Management of chronic heart failure. Edinburgh: SIGN; 2016. (SIGN publication no. 147). [cited 03 Oct 2022]. Available from URL: https://www.sign.ac.uk/our-guidelines/management-of-chronic-heart-failure/
2. National Institute for Health and Care Excellence. Chronic heart failure in adults: diagnosis and management [Internet]. [London]: NICE; 20018 [cited 2022 Oct 03]. (Nice Guidline [NG 106]). Available from: https://www.nice.org.uk/guidance/ng106

A PDF summary document is available here.