From the Guidelines
Elevated BNP levels are primarily caused by heart failure, as well as other cardiac conditions such as acute coronary syndromes, pulmonary embolism, and myocarditis, as outlined in the 2016 ESC guidelines 1. The causes of elevated BNP can be categorized into cardiac and non-cardiac conditions.
- Cardiac causes include:
- Heart failure
- Acute coronary syndromes
- Pulmonary embolism
- Myocarditis
- Left ventricular hypertrophy
- Hypertrophic or restrictive cardiomyopathy
- Valvular heart disease
- Congenital heart disease
- Atrial and ventricular tachyarrhythmias
- Heart contusion
- Cardioversion, ICD shock
- Surgical procedures involving the heart
- Pulmonary hypertension
- Non-cardiac causes include:
- Advanced age
- Ischaemic stroke
- Subarachnoid haemorrhage
- Renal dysfunction
- Liver dysfunction (mainly liver cirrhosis with ascites)
- Paraneoplastic syndrome
- Chronic obstructive pulmonary disease
- Severe infections (including pneumonia and sepsis)
- Severe burns
- Anaemia
- Severe metabolic and hormone abnormalities It is essential to consider the patient's overall clinical picture when interpreting elevated BNP results, as levels above 100 pg/mL suggest cardiac dysfunction, while values exceeding 400 pg/mL strongly indicate heart failure, as noted in the 2016 ESC guidelines 1.
From the Research
Possible Causes for Elevated BNP
Elevated B-type natriuretic peptide (BNP) levels can be caused by various cardiac and non-cardiac conditions. Some of the possible causes include:
- Cardiac disease states such as congestive heart failure (CHF), acute coronary syndromes, diastolic dysfunction, atrial fibrillation (AF), amyloidosis, restrictive cardiomyopathy (RCM), and valvular heart disease 2, 3
- Non-cardiac diseases such as pulmonary hypertension, chronic obstructive pulmonary disease, pulmonary embolism, and renal failure 2, 3
- Critical illness such as acute decompensated CHF (ADHF) and sepsis 2, 4
- Other conditions such as left ventricular hypertrophy, cor pulmonale, lung cancer, and circulatory overload 3
- Factors such as age, gender, and body mass index (BMI) can also influence BNP levels 2
Predictors of Elevated BNP Levels
Independent predictors of elevated BNP levels in patients without congestive heart failure include:
- Medical history of atrial fibrillation
- Radiographic cardiomegaly
- Decreased blood hemoglobin concentration
- Decreased body mass index
- Increased age 5
Diagnostic and Prognostic Impact of BNP
BNP assay is useful for evaluating patients with acute dyspnea, and can help rule out CHF in primary care settings 4. However, the specificity of BNP in CHF is not strong, and other mechanisms beyond simple ventricular stretch stimulate BNP release 4. BNP levels can be elevated in multiple disorders, including cardiovascular disease states and disorders of no cardiac origin, such as sepsis and acute respiratory distress syndrome 4.