WELCOME BNP testing

Aims of this education package Better understanding of what BNP testing is How to appropriately use the test How to request the test What to do with the results

BNP – Brain Type Natriuretic peptide 1988 Identified from porcine brain Later on isolated from heart muscle

BNP – how is it produced? Fluid Overload Ventricular stretch NT- proBNP BNP Pro BNP

What does BNP do ? BNP Water loss in kidneys Vasodilatation Natriuresis Decreased plasma volume and BP Fluid overload

What other things affect BNP test BNP test is increased –Renal failure –Pulmonary hypertension –Chronic hypoxia –PE –Age>70 –LVH –Ischaemia –Valvular heart disease –AF –Sepsis –Hyperthyroidism –Liver cirrhosis BNP test is decreased –Obesity –Diuretics, ACE/ARB, beta blockers

Bolton Heart Failure Audit

The problem with clinical diagnosis of heart failure Symptom / SignSensitivity ( % )Specificity ( %) Dyspnoea6652 Orthopnoea2181 PND3376 Odema2380 Raised JVP rd HS3195 Peripheral Odema1093 Tachycardia799 Crepitation1391 Harlan WR et al ; Chronic Congestive Heart Failure in coronary artery disease : a clinical criteria. Ann Intern Med 1977:86:133-8

BNP – diagnostic test BNP levels of more than 100 pg/ml have a greater than 95% specificity and greater than 98% sensitivity Hobbs FD, Davis RC, Roalfe AK, et alHobbs FD, Davis RC, Roalfe AK, et al; Reliability of N-terminal pro-brain natriuretic peptide assay in diagnosis of heart failure: cohort study in representative and high risk community populations. BMJ Jun 22;324(7352):1498. If BNP level is less than 100pg/ml i.e NEGATIVE then its highly unlikely the symptoms (breathlessness) are due to heart failure

Is it cost effective ?

Benefits of BNP testing Sensitive and specific to rule out heart failure Simple test to do Cost effective Improves patient experience and journey with a more efficient diagnostic pathway

How to request test and pathway It is a blood test and sent to the RBH laboratory Use a normal form or Anglia ICE system if possible Because of instability of BNP, the sample should be processed by lab within 4 hours of taking the blood sample. So if bloods are taken in house, make sure it is the last blood test of the morning or do blood test close to time of collection

Take 2 red bottles and one brown bottle. This will enable the BNP test to be done as well as FBC, electrolytes, LFTs and TFTs at the same time. These are useful tests in the preliminary assessment of someone who is breathless or with heart failure Then put in the brown envelope with yellow circle marked BNP test (so lab can identify sample quickly ) Results with come through the normal path lab link X 1 X 2

What to do when you get the BNP test back? BNP< 100pg/ml BNP< 100pg/ml NORMAL Review patient and consider other diagnosis for breathlessness with the help of history, examination and the following tests if not already done: 1. CXR 2. Spirometry 3. Blood tests/ D-Dimer 4. ECG Refer to respiratory medicine if needed

What do when you get the BNP test back? BNP 100–400 pg/ml BNP 100–400 pg/ml Raised Refer to direct access cardiology echocardiogram clinic ROUTINE ( usually within 6 weeks )

What do when you get the BNP test back? BNP> 400pg/ml BNP> 400pg/ml HIGH Refer to direct access cardiology echocardiogram clinic URGENT – should be seen within 2 weeks

Summary BNP test is used to help identify possible HF Request 2 red tubes and 1 brown tube for BNP, FBC, U&E, LFT, TFT Sample to be taken late am close to collection Echocardiogram is GOLD STANDARD needed to confirm diagnosis DO NOT –Use BNP test to predict prognosis –Use to monitor response to treatment –repeat BNP tests unless clinical change If BNP negative –unlikely patient has heart failure – investigate for other causes for breathlessness/ symptoms. If you still feel this maybe due to heart failure please discuss with the cardiologist before referring for echocardiogram Positive BNP refer for direct access echocardiogram and cardiology review