Initial investigations in primary care

Carry out ———— tests in ——- care. Be aware of the threshold of —————-

• baseline

• primary

• NT-proBNP

What does NT-proBNP stand for?

• N-terminal pro-B-type natriuretic peptide

Measurement of what is reccommended by NICE in the UK for any patient with suspected possible heart failure?

• N-terminal pro-B-type natriuretic peptide (NT-proBNP)

When are natriuretic produced?

• Natriuretic peptides are produced by the left ventricle in response to stress on the ventricular wall

Are natriuretic peptides a diagnostic test for heart failure?

• No, natriuretic peptides are markers of cardiac stress

What should you refer a patient to if they have a raised natriuretic peptide?

• Transthoracic echocardiography and a specialist assessment to determine whether heart failure is the diagnosis

What sensitivity and specificity does NT-proBNP have for heart failure?

• high sensitivity

• modest specificity

What is the current threshold in the UK of NT-proBNP?

• 400 ng/L (47 pmol/L)

What happens if a patient has a natriuretic peptide value below the threshold?

• In a patient not receiving treatment, this excludes chance of significant heart failure

• need to consider alternative causes of patient’s symptoms

What is the threshold for NT-proBNP that the European Society of Cardiology reccommend?

• 125 ng/L

What is the advantage of the NT-proBNP threshold by NICE compared to the European Society of Cardiology?

• It’s the most cost effective

In some areas what is measured rather than NT-proBNP, and how do the two compare?

• BNP is measured instead

• they differ e.g. a BNP of 800 ng/L is a very high level compared to a NT-proBNP of 800 ng/L which is only a modest rise

What is the NICE guideline for if a patient has a NT-proBNP more than 2000 ng/L (236 pmol/L)?

• Refer these patients for transthoracic echocardiography and a specialist assessment within two weeks

• The rationale for this is that very high level of serum natriuretic peptides carry a poor prognosis

What is the NICE guideline for if a patient has a NT-proBNP of 400 ng/L to 2000 ng/L (47 pmol/L to 236 pmol/L)?

• Suggests a moderate probability of heart failure

• Refer these patients for transthoracic echocardiography and a specialist assessment within six weeks

What is the NICE guideline for if a patient has a NT-proBNP less than 400 ng/L (47 pmol/L)?

• Heart failure is unlikely. Consider alternative causes for symptoms

What is the NICE guideline for patients with suspected heart failure who have had previous myocardial infarction?

• should still have their NT-proBNP measured before referral for echocardiography and specialist assessment

What can reduce levels of natriuretic peptide?

• obesity

• African or African-Caribbean family origins

• diuretics

• angiotensin-converting enzyme (ACE) inhibitors

• beta blockers

• angiotension II receptor antagonists (ARBs)

• mineralocorticoid receptor antagonist (MRA) such as spironolactone

What should you do if a patient has low natriuretic peptide levels because of treatment they’ve been receiving but you suspect heart failure?

• seek specialist advice

The sooner disease ———- therapy can be started, the better the ———- is likely to be.

• modifying

• outcome

What are tests other than natriuretic peptides to request in primary care in patients with suspected heart failure?

• ECG

• Chest x ray

• Full blood count

• Electrolytes

• Creatinine

• Estimated glomerular filtration rate (eGFR)

• Liver function tests

• Thyroid function tests

• Lipids

• Glycosylated haemoglobin (HbA1c)

• Urinalysis

• Peak flow or spirometry

• Oxygen saturations

What signs could ECG detect?

• signs of previous mycocardial infarction (e.g. Q waves)

• rhythm disturbance associated with heart failure like atrial fibrillation

• heart rhythm

• rate

• QRS morphology

• QRS duration

  Specific abnormalities:

  • atrioventricular (AV) block

  • evidence of left ventricular hypertrophy

What differential diagnoses can a chest x ray detect or exclude?

• lung cancer = can mimic or coexist with heart failure

• pulmonary congestion (more useful for detecting this in an acute setting than primary care)

• oedema

.———- on a chest x ray is an unreliable sign compared with —————

• cardiomegaly

• echocardiography

There is no guidance on the ———— of patients with ———— on a chest x ray (including those with an ——— finding of cardiomegaly). It is prudent to refer the patient for ————- to investigate further if there is cardiomegaly on a chest x ray

• management

• incidental

• incidental

• echocardiography

What is a frequent cause of cardiomegaly on chest x ray?

• dilatation of the atria in patients with atrial fibrillation

What can full blood count detect?

• anaemia, could be altrenative cause of symptoms or could be worsening heart failure

• can adversely affect prognosis

What can electrolytes, creatinine, estimated glomerular filtration rate (eGFR), and liver function tests detect?

• help identify cause of heart failure e.g. alcohol excess or identify alternative causes of fluid retention like nephrotic syndrome or cirrhosis of the liver

What are electrolytes, creatinine, estimated glomerular filtration rate (eGFR), and liver function tests necessary for?

• to obtain a baseline assessment of renal function to assess suitability for treatment with drugs like:

  • diuretics

  • ACE inhibitors

  • mineralocorticoid antagonists (also known as aldosterone antagonists e.g. spironolactone)

  • sacubitril-valsartan

    all of which may cause deterioration in renal function

What is the importance of thyroid function tests?

• to detect throid dysfunction, as hypothyroidism or hyperthyroidism may be a reversible cause of heart failure

What is peak flow or spirometry and oxygen saturations used to detect?

• chronic obstructive pulmonary disease (COPD) or pulmonary embolism as an alternate cause for breathlessness

What can both COPD and pulmonary embolism cause?

• right sided heart failure by producing hypoxia and pulmonary hypertension (cor pulmonale)