What is the usefulness of B-type natriuretic peptide (BNP)?

From the Guidelines

B-type natriuretic peptide (BNP) is a highly useful diagnostic tool in clinical decision making for heart failure, particularly in cases of clinical uncertainty. The measurement of BNP or N-terminal pro-B-type natriuretic peptide (NT-proBNP) is useful to support clinical decision making in the diagnosis of heart failure, especially when there is clinical uncertainty 1. This is evident from the 2013 ACCF/AHA guideline for the management of heart failure, which states that measurement of BNP or NT-proBNP is useful for establishing prognosis or disease severity in chronic heart failure (Level of Evidence: A) 1.

Key Points to Consider

• BNP levels can be used to differentiate cardiac failure from other causes of dyspnea, with a level of 100 pg.ml-1 identified as the optimal cut-off point (90% sensitivity, 76% specificity) 1.
• The use of dual cut-off points, with an exclusion level < 300 pg.ml-1 (98% negative predictive value) and an inclusion level > 900 pg.ml-1 (76% positive predictive value), can result in further improved diagnostic ability 1.
• BNP levels should be regarded as a continuous variable, with even mildly elevated levels being associated with increased risk of death, heart failure, atrial fibrillation, and stroke 1.
• The usefulness of serial measurement of BNP or NT-proBNP to reduce hospitalizations or mortality in patients with heart failure has not been established 1.

Clinical Application

In clinical practice, BNP or NT-proBNP measurement can be a valuable tool in diagnosing and managing heart failure, particularly in ambulatory patients with dyspnea and in cases where clinical uncertainty exists 1. However, it is essential to consider the limitations and potential causes of elevated BNP levels, as well as the need for careful interpretation of results in the context of individual patient circumstances.

From the Research

Usefulness of BNP

• BNP is a useful clinical tool for the diagnosis, prognosis, and management of heart failure (HF) patients 2.
• Studies have consistently demonstrated high sensitivity, specificity, and negative predictive value of BNP levels in diagnostic situations 2.
• BNP can be used to assist in diagnosing HF in emergency and outpatient situations, particularly when the presenting symptom is dyspnea 2, 3.
• BNP levels can also be used to determine HF prognosis, including predicting death and cardiac events 2, 3.
• A BNP-guided strategy has been shown to reduce the risk of CHF-related death or hospital stay for CHF 4.

Limitations of BNP

• BNP cannot differentiate between systolic and diastolic HF 2.
• BNP levels can vary depending on multiple confounders, making clinical interpretation difficult 2.
• The prognosis for patients with CHF remains poor, despite the use of BNP and other pharmacological agents 5.

Potential Future Developments

• BNP, or a derivative thereof, has great potential for the treatment of patients at various stages in the progression of heart failure 5.
• Nesiritide, the human recombinant form of BNP, is a new vasodilator used in the treatment of acute heart failure 3.
• Further research is needed to fully explore the potential of BNP in the management of heart failure 6.