From the Guidelines
BNP, or B-type natriuretic peptide, is a hormone released by the heart ventricles when they are stretched due to increased pressure or volume, serving as an important biomarker for diagnosing and monitoring heart failure. When the heart is under stress, it releases more BNP into the bloodstream, making elevated BNP levels a reliable indicator of heart failure.
Key Points
- Normal BNP levels are typically below 100 ng/L, while levels above 400 ng/L strongly suggest heart failure, as defined by the National Institute for Health and Clinical Excellence guideline 1.
- Healthcare providers use BNP testing to help diagnose heart failure, assess its severity, guide treatment decisions, and monitor a patient's response to heart failure therapy.
- BNP works in the body by promoting diuresis (increased urine production), vasodilation (widening of blood vessels), and inhibiting harmful neurohormonal systems that can worsen heart failure.
- This test is particularly valuable in emergency settings to distinguish between heart failure and other conditions that cause similar symptoms like shortness of breath.
Clinical Use
- Measurement of BNP or NT-proBNP is useful to support clinical decision making in the diagnosis of heart failure, especially when there is clinical uncertainty, as stated in the ACCF and AHA guidelines 1.
- BNP- or NT-proBNP–guided therapy can be useful to achieve optimal dosing of medical therapy in select clinically euvolemic outpatients in structured management programs.
- The usefulness of serial measurement of BNP or NT-proBNP to reduce hospitalizations or mortality in patients with heart failure has not been established, as noted in the ACCF and AHA guidelines 1.
From the Research
Definition of BNP
- BNP stands for Brain Natriuretic Peptide, a cardiac hormone produced in the heart 2, 3, 4, 5, 6
- It is a member of the natriuretic peptide family, which plays a cardioprotective role in heart failure 2
- BNP is abundantly expressed and secreted in the ventricles, and its levels increase in patients with heart failure 2, 3, 4
Physiological Functions of BNP
- BNP exhibits diuretic/natriuretic actions, vasodilatory actions, and inhibition of aldosterone secretion, which are antagonistic to the effects of angiotensin II 2
- It is involved in the regulation of cardiovascular homeostasis and disease, and its levels are used as a biomarker for heart failure 2, 3, 4
- BNP is also produced by cells infiltrating the heart, such as endothelial cells, T cells, and macrophages, in patients with severe heart failure 5
Clinical Significance of BNP
- BNP levels are increased in patients with heart failure, and low levels of BNP rule out heart failure 3
- BNP-guided therapy has been shown to improve outcomes in heart failure patients, by reducing the risk of heart failure-related death or hospital stay 6
- The measurement of BNP levels can be used to monitor the effectiveness of treatment and to adjust medication dosages 6