Question

Is BNP always elevated in Heart Failure?

Answer 1

B-type natriuretic peptide (BNP) is a kind of hormone produced by the heart. N-terminal (NT) prohormone BNP (NT-pro BNP) is a non-active prohormone released from the same molecule that produces BNP. In response to changes in pressure inside the heart, both BNP and NT-proBNP are released. The changes are related to cardiac problems and heart failure. Levels of BNP and NT-proBNP are measured and evaluated as a simple blood test to diagnose and monitor heart failure.

Complete answer
When heart failure gets worse or develops, the levels of BNP and NT-proBNP go up. At the same time, the levels go down when heart failure becomes stable. So, in most cases, levels of NT-proBNP and BNP are enhanced in patients having heart failure than the people having normal heart function.

BNP is very helpful in the diagnosis of heart failure. A normal BNP level is 98% accurate in ruling out the diagnosis, thus allowing doctors to search for other conditions, which cause fluid retention or shortness of breath.

Most of the patients who do not have true heart failure, have increased levels of BNP, because of severe kidney or lung disease.

Increasing age, lung disease, high blood pressure, and female gender enhance the BNP levels during non cardiac conditions. At the same time, obesity, ACE inhibitors, medications, and spironolactone mitigates the level of BNP.

BNP levels below 100 picograms per milliliter rule out heart failure as the cutoff value is 200 picograms per milliliter for patients with kidney failure.

Higher BNP levels are inconclusive. But, in patients with suspected heart failure, BNP levels of 900 picrograms per milliliter in 50-75 years and above pictograms per milliliter in older patients, support the diagnosis 90% of the time.

The result aids the doctor to determine if the patient has heart failure, worsening fatigue, shortness of breath due to heart failure, or another problem or heart failure progressing towards the end of life.

Note:
Patients with treated chronic stable heart failure can have normal levels of BNP and NT-proBNP. BNP level is associated with cardiac status. It is a strong predictor of the risk of death and cardiovascular events in patients, who have been previously diagnosed with cardiac dysfunction or heart failure. A highly negative value of BNP is specifically helpful for ruling out heart failure.