Transcript BNP Testing For Heart failure

BNP testing
WELCOME
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
Pro BNP
NT- proBNP
BNP
What does BNP do ?
Water loss in
kidneys
BNP
Vasodilatation
Natriuresis
Fluid overload
Decreased
plasma
volume and
BP
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 / Sign
Sensitivity ( % )
Specificity ( %)
Dyspnoea
66
52
Orthopnoea
21
81
PND
33
76
Odema
23
80
Raised JVP
10
97
3rd HS
31
95
Peripheral Odema
10
93
Tachycardia
7
99
Crepitation
13
91
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 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. 2002 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
X2
X1
What to do when you get
the BNP test back?
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
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
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