Plasma B-type natriuretic peptide levels in ambulatory patients with established chronic symptomatic systolic heart failure

Background - The diagnostic and prognostic values of plasma B-type natriuretic peptide (BNP) testing are established. However, the range of plasma BNP levels present in the setting of chronic, stable systolic heart failure (HF) is unclear. Methods and Results - We followed up 558 consecutive ambulatory patients with chronic, stable systolic HF ( left ventricular ejection fraction < 50%) treated at a specialized outpatient HF clinic between November 2001 and February 2003. Retrospective chart review was performed to determine clinical and functional data at the time of BNP testing (Biosite Triage). The clinical characteristics of patients with plasma BNP levels < 100 pg/mL and those with greater than or equal to 100 pg/mL were compared. In our cohort, 60 patients were considered asymptomatic, and their plasma BNP levels ranged from 5 to 572 pg/mL ( median, 147 pg/mL). Of the remaining 498 symptomatic (NYHA functional class II-III) patients, 106 (21.3%) had plasma BNP levels in the "normal" diagnostic range ( < 100 pg/mL). Patients in this "normal BNP" subgroup were more likely to be younger, to be female, to have nonischemic pathogenesis, and to have better-preserved cardiac and renal function and less likely to have atrial fibrillation. Conclusions - In the ambulatory care setting, both symptomatic and asymptomatic patients with chronic, stable systolic HF may present with a wide range of plasma BNP levels. In a subset of symptomatic patients ( up to 21% in our cohort), plasma BNP levels are below what would be considered "diagnostic" ( < 100 pg/mL).