Identification and guided treatment of ventricular dysfunction in general practice using blood B-type natriuretic peptide

BACKGROUND: B-type natriuretic peptide (BNP) is a blood test which detects ventricular wall stretch and is being increasingly used in primary care on limited evidence. AIM: To assess the practical implications and potential clinical benefit of measuring BNP to identify and guide the treatment of undiagnosed or under-treated ventricular dysfunction in at-risk patients. DESIGN OF STUDY: Screening study with single-arm intervention. SETTING: A total of 1918 patients with diabetes mellitus or ischaemic heart disease aged > or =65 years registered with 12 general practices were invited; 76 patients with elevated BNP underwent BNP-guided treatment titration. METHOD: Eligible patients were invited to attend for a blood test at their own practice; those with a persistently elevated plasma BNP concentration (>43.3 pmol/l) after repeat measurement were offered initiation or up-titration of treatment guided by remeasurement of BNP with a target concentration of <36 pmol/l. RESULTS: Seven-hundred and fifty-nine patients (40%) attended for screening; 76 (10% of 759) commenced treatment titration. Of these 76 patients, 64 (84%) were asymptomatic or had only mild breathlessness. Maximum titration effect was achieved by the second visit when 27 (36%) had achieved the BNP target concentration and the mean reduction was 10.8 pmol/l (P<0.001). The most effective therapeutic step was a switch in beta-blocker to carvedilol or bisoprolol (P<0.001). CONCLUSION: About 10% of patients with diabetes or cardiovascular disease on GP morbidity registers have a persistently raised plasma BNP concentration. Simple adjustment of their drug treatment may reduce their BNP and associated mortality risk, but further up-titration against BNP is only possible if the within-person biological variability of measurement can be reduced.