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

Abstract

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. >1694pg/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 56years, 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 (30days: P=0.01, 180days: 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.