Prospective evaluation and long term follow up of patients referred to secondary care based upon natriuretic peptide levels in primary care.

Objectives: The UK National Institute for Health and Care Excellence (UK-NICE) and European Society of Cardiology (ESC) guidelines advise natriuretic peptide (NP) assessment in patients presenting to primary care with symptoms possibly due to chronic heart failure (HF), to determine need for specialist involvement. This prospective service evaluation aimed to describe the diagnostic and prognostic utility of these guidelines.

Methods: We prospectively collected clinical, echocardiography and outcomes data (minimum 5yrs) from all patients referred to the Leeds HF Service for 12m following the initiation of the NP-guideline-directed pathway.

Results: Between May 1st 2012 and August 1st 2013, 1020 people with symptoms possibly due to HF attended either with a raised NT-pro-BNP or a previous myocardial infarction (MI) with an overall rate of LVSD of 33%. Of these, 991 satisfied the ESC criteria (NT-pro-BNP ≥125pg/mL) in whom the rate of LVSD was 32%, and 821 the UK-NICE criteria in whom the rate of LVSD was 49% in those with a previous MI, 25% in those with NT-pro-BNP concentration 400-2000pg/mL and 54% in those with NT-pro-BNP concentration of >2000pg/mL. An NT-pro-BNP concentration 125-400pg/mL had a 12% risk of LVSD. Specificity was poor in women >70yrs, who made up the largest proportion of attendees. Elevated NT-pro-BNP levels were associated with lower survival even in the absence of LVSD.

Conclusion: In people referred through the ESC and UK-NICE guidelines, elevated NT-pro-BNP is a marker of increased mortality risk, but there is wide variation in specificity for LVSD. Age- and sex-adjusted criteria might improve performance.