Contributor: Chris Sobowale

Heart failure patients with HFrEF and atrial fibrillation (HFrEF-AF) have higher NT-proBNP than HFrEF patients without atrial fibrillation (AF). This is thought to be a consequence of AF and not necessarily correlated with deleterious clinical outcomes.

HF clinical trials have stipulated different inclusion NT-proBNP levels for patients with HFrEF-AF. It turns out, a defined higher NT-proBNP level for patients with HFpEF-AF may not be necessary.

Two major HF trials (including over 14,000 HFrEF patients) were evaluated: PARADIGM-HF and ATMOSPHERE. The inclusion criteria were: NYHA class II-IV, EF ≤35% and a BNP ≥150 pg/mL or NT-proBNP ≥600 pg/mL. If hospitalized for heart failure within 12 months before the study, patients could enroll with a lower BNP 100pg/ml or NT-proBNP ≥ 400pg/ml.

The primary endpoints for both trials were: 1) composite of CV death and HF hospitalization, 2) CV death, 3) HF hospitalization, and 4) all-cause mortality. Baseline NT-proBNP was measured at time of screening in both trials.

Indeed, HFrEF-AF patients had higher NT-proBNP. However, between 400 pg/ml and 8000 pg/ml, risk of cardiovascular death and/or HF hospitalization was similar for any BNP level, whether or not patients had AF. This was true in adjusted and unadjusted analysis.

No study is perfect. HFrEF-AF patients with a NT-proBNP of ≤400 pg/ml had higher events rates than those without AF, but this could be related to the small number of HFrEF-AF patients. This study is retrospective, largely a male cohort (roughly 80%), and represents only HFrEF patients.

In a heartbeat… NT-proBNP above 400 pg/ml has similar predictive value for adverse outcomes in HFrEF patients with or without AF. Higher thresholds for NT-proBNP clinical trial inclusion may not be necessary in patients with atrial fibrillation.

Study Link: Prognostic Value of N-Terminal Pro-B-Type Natriuretic Peptide Levels in Heart Failure Patients With and Without Atrial Fibrillation