Dr Aniket Gadre explains the importance of this simple test in identifying complications of the heart
Heart failure is a leading cause of complications and death in people with heart disease. The diagnosis of heart failure remains essentially clinical based on history, physical examination and chest radiograph findings. However, clinical findings and examination alone are often inadequate in diagnosing heart failure as multiple other conditions related to the heart and lungs mimic the symptoms of heart failure. This may lead to misdiagnosis and delays the initiation of appropriate management. In such cases, the existence of a biomarker that could accurately identify heart failure as the cause of a person’s symptoms would be extremely helpful in timely medical care.
Natriuretic peptides, namely BNP and NT- proBNP, present themselves as such markers and are now being widely used in diagnosing and managing heart failure.
Natriuretic peptides are proteins secreted by the muscles of the heart in response to the volume or pressure. They are secreted
in response to volume or pressure overload.
When you have heart failure, your heart makes two proteins. Your doctor will call them B-type natriuretic peptide (BNP) and N-terminal-pro-BNP (NT-pro-BNP). Levels of both in your blood go up when your heart failure gets worse and go down when it gets better.
Importance of the test
BNP levels help your doctor figure out if you have heart failure or something else that has similar symptoms such as shortness of breath. The test also shows if your heart failure has worsened. It’ll help your doctor decide what treatments you need and if you need to be hospitalized. It
may also give him a look into what the future may hold. It is a sensitive test to allow the doctor to evaluate improvement or worsening of heart failure and to help monitor whether or not the medication is working well
Reference Range
The reference values of brain-type natriuretic peptide (BNP) and N- terminal (NT) proBNP are different to exclude or confirm a diagnosis of heart failure. These
values also depend on age and gender and are higher in elderly persons and women. In general, the following cut off values may be employed for acutely breathless patients
BNP:
- < 100 pg/mL – HF unlikely
- >400 pg/mL – HF likely
- 100-400 pg/mL – Use clinical judgement
- NT-proBNP
- < 300 pg/mL – HF unlikely
- Age < 50 years, NT-proBNP >450 pg/mL – HF likely
- Age 50-75 years, NT-proBNP >900 pg/mL HF likely
- Age >75 years, NT-proBNP >1800 pg/mL HF likely
What happens during the test?
A small amount of blood will be taken from your vein. Then it’s placed in a machine that reads the level of BNP and NT-pro-BNP.
Conditions associated with elevated BNP other than heart failure are as follows:
- Acute renal failure and chronic renal failure
- Hypertension
- Lung diseases like chronic obstructive pulmonary disease, pulmonary embolism, adult respiratory distress syndrome
- Cardiac causes – Myocardial infarction, atrial fibrillation, acute coronary syndrome, heart disease
- Older age
- Female
- Liver cirrhosis
- Sepsis
Dr Aniket Gadre is a consultant Cardiologist.
