N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a commonly used biomarker in the detection, diagnosis, and evaluation of heart failure. Studies suggest that in heart failure patients with preserved ejection fraction, the association between NT-proBNP and outcome may vary significantly according to the presence or absence of atrial fibrillation. Higher levels of NT-proBNP being less predictive of heart failure among individuals with atrial fibrillation compared to those without.
Across two trials (the TOPCAT trial and the I-Preserve studies) comprising a total of 3835 heart failure patients with preserved ejection fraction patients, 719 patients (19%) had atrial fibrillation according to their baseline ECG. Patients with and without atrial fibrillation were categorized into one of 4 NT-proBNP threshold levels: <400, 400 – 999, 1000 – 1999 or ≥ 2000 pg/mL. In the low NT-proBNP group (<400 pg/mL), cardiovascular death or heart failure hospitalization was observed to be higher in the presence of atrial fibrillation (3.2 vs 8.0 events per 100 patient-years, non-atrial fibrillation patients vs atrial fibrillation patients respectively). For higher NT-proBNP levels, the opposite was seen, whereby patients with atrial fibrillation displayed less events than those without atrial fibrillation (13.2 vs 11.4 events per 100 patient-years with NT-proBNP 1000–1999 pg/mL and 25.6 vs 17.4 events per 100 patient-years with NT-proBNP ≥2,000 pg/mL, non-atrial fibrillation patients vs atrial fibrillation patients respectively).
These findings show that when NT-proBNP is <400 pg/mL, absolute event rates are lower in the absence of atrial fibrillation. As NT-proBNP increases, the relationship between biomarker level and cardiovascular outcomes changes, with a lower absolute risk of cardiovascular death or heart failure hospitalization being observed in patients with atrial fibrillation. This suggests that higher NT-proBNP levels may be of lesser prognostic value in patients with atrial fibrillation than in those without, making the presence/absence of atrial fibrillation a key factor when considering NT-ProBNP as a predictive biomarker in HF.
Original article: Circ Heart Fail 2019;12:e005766.
Author: Daniel Guns, Cardiology Update