- the NICE clinical guideline on CHF the use of BNP as a diagnostic tool for heart failure (1,2)
- refer patients with suspected heart failure and previous myocardial infarction (MI) urgently, to have transthoracic Doppler 2D echocardiography and specialist assessment within 2 weeks (1)
- refer people with suspected heart failure and an NT-proBNP level above 2,000 ng/litre (236 pmol/litre) urgently, to have specialist assessment and transthoracic echocardiography within 2 weeks - because very high levels of NT-proBNP carry a poor prognosis
- refer people with suspected heart failure and an NT-proBNP level between 400 and 2,000 ng/litre (47 to 236 pmol/litre) to have specialist assessment and transthoracic echocardiography within 6 weeks
- review alternative causes for symptoms of heart failure in people with NTproBNP levels below 400 ng/litre. If there is still concern that the symptoms might be related to heart failure, discuss with a physician with subspeciality training in heart failure
- perform transthoracic echocardiography to exclude important valve disease, assess the systolic (and diastolic) function of the (left) ventricle, and detect intracardiac shunts
- if a poor image is produced by transthoracic echocardiography
- consider alternative methods of imaging the heart (for example, radionuclide angiography [multigated acquisition scanning], cardiac MRI or transoesophageal echocardiography)
- the level of serum natriuretic peptide does not differentiate between heart failure due to left ventricular systolic dysfunction and heart failure with preserved left ventricular ejection fraction
Also perform an ECG and consider the following tests to evaluate possible aggravating factors and/or alternative diagnoses:
- chest X-ray
- blood tests:
- electrolytes, urea and creatinine - eGFR (estimated glomerular filtration rate)
- thyroid function tests
- liver function tests
- fasting lipids
- fasting glucose
- full blood count
- urinalysis
- peak flow or spirometry
When a diagnosis of heart failure has been made, assess severity, aetiology, precipitating factors, type of cardiac dysfunction and correctable causes
Notes:
- serum natriuretic peptides:
- obesity, African or African-Caribbean family origin, or treatment with diuretics, angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, angiotensin II receptor blockers (ARBs) or mineralocorticoid receptor antagonists (MRAs) can reduce levels of serum natriuretic peptides
- high levels of serum natriuretic peptides can have causes other than heart failure (for example, age over 70 years, left ventricular hypertrophy, ischaemia, tachycardia, right ventricular overload, hypoxaemia [including pulmonary embolism], renal dysfunction [eGFR less than 60 ml/minute/1.73m2], sepsis, chronic obstructive pulmonary disease, diabetes, or cirrhosis of the liver)
Reference: