GPs urged to choose lab-based test to rule out heart failure
Research at the British Cardiac Society annual conference this month covered aspects of GP care. Brian Kelly reports
One of two tests to be recommended by the Government for GPs to rule out heart failure is much better than the other, research suggests.
The researchers found the N-terminal pro-brain natiuretic peptide (NT-proBNP) test, a blood test processed in the laboratory, avoided inappropriate referrals without missing as many patients with heart failure as the near-
patient B-type natiuretic peptide (BNP) test.
The National Institute for Clinical Excellence will release guidance this summer telling GPs to use one or other of the tests to exclude suspected heart failure before referring patients for an echocardiogram to avoid swamping the service.
But GPs will get no guidance on which of the tests to choose.
Study leader Dr Ahmet
Fuat, research fellow at the University of Durham and a GP in Darlington, compared the two tests in 120 patients referred from primary care to a heart failure clinic.
The NT-proBNP test had the highest negative predictive value at 97 per cent, which avoided 31 per cent of referrals and missed just one patient with left ventricular systolic dysfunction (LVSD). This result was based on a cut-off of 150pg/ml. Patients with
levels under this value were highly unlikely to have heart failure.
The results showed for BNP, the highest negative predictive value was 88 per cent when using a cut-off of 40pg/ml. This avoided 42.5 per cent of referrals but would have missed six patients with LVSD.
Dr Fuat said: 'It was a small study but suggests one test is better than the other. NT-proBNP is easier for GPs to use because you just take some blood and send it off to the laboratory.'
He said equipment for the BNP assay cost around £2,000 plus £15 per kit.
Dr Fuat added he would soon roll out a study using 600 NT-proBNP tests in 30 practices to see if it avoided inappropriate hospital admissions and echo referrals.
Professor Martin Cowie, professor of cardiology at the Royal Brompton Hospital in London and clinical adviser
to the NICE guidelines on heart failure, said there was
little to choose between the two tests.
He said: 'There is no clinically significant difference between the two peptides and which test to use should be left up to local health care communities.
'For a large group practice the point-of-care test might be more useful but other GPs might find it easier to send
it off with all the other blood tests.'