Extremely elevated BNP in acute heart failure: Patient characteristics and outcomes

BackgroundWe explored the clinical characteristics and outcomes of patients with acute systolic heart failure (HF) and extremely elevated admission B-type natriuretic peptide (BNP).MethodsExtremely elevated BNP was defined if BNP level was > 85th percentile of the study cohort (i.e. > 1694 pg/mL). Our objectives were to find characteristic features that identify patients with extremely elevated BNP, to compare the degree of congestion in both groups and to study post-discharge outcomes.Results347 patients (mean age 56 years, 74% males) were divided into two groups based on whether BNP was extremely elevated (n = 53) or not (n = 294). Those with extremely elevated BNP were older (P = 0.004), with a lower body mass index (P < 0.0001), higher blood urea nitrogen (P = 0.01), higher creatinine (P = 0.005), lower cardiac output (P < 0.0001) and lower cardiac index (P = 0.001). With regards to signs of congestion, both groups had no significant difference in the frequency of rales (P = 0.454), peripheral edema (P = 0.397), jugular venous distension (P = 0.396), positive hepatojugular reflux (P = 0.083), S3 gallop (P = 0.107), mean pulmonary capillary wedge pressure (P = 0.351), and right atrial pressure (P = 0.310). Both groups had similar frequency of rehospitalization for HF (P = 0.939), nonetheless, patients with extremely elevated BNP had longer hospital stay during initial (P = 0.014), or subsequent hospitalization (30 days: P = 0.01, 180 days: P = 0.008). 6-month all-cause-mortality was higher in patients with extremely elevated BNP (P = 0.008), although death due to pump failure was not (P = 0.921). Cox proportional hazard analysis revealed that extremely elevated admission BNP is an independent predictor of 6-month all-cause-mortality (hazard ratio 1.857, 95% CI = 1.074-3.208, P = 0.027) after adjustment for known predictors of post-discharge mortality in HF.ConclusionExtremely elevated admission BNP did not match the degree of congestion nor was a predictor of rehospitalization due to HF. It was associated with decreased COP, prolonged hospital stay, and increased 6-month all-cause-mortality.