Brain Natriuretic Peptide Helps Prognosticate Improvement in Renal Function in Acute Heart Failure

Abstract

Introduction We aimed to evaluate the prognostic implications of improved renal function (IRF) in acute heart failure (AHF) and the relationship with regards to measures of congestion. Hypothesis: AHF patients with IRF experience worse outcomes than those with no change or worsening in renal function, but this may be from insufficient decongestion. Methods The Acute Kidney Injury NGAL Evaluation of Symptomatic heart faIlure Study (AKINESIS) was a prospective, international, multicenter study of AHF patients. We investigated the relationship between IRF, changes in brain natriuretic peptide (BNP) and one-year mortality. IRF was defined as a decrease in creatinine of > 0.3 mg/dl at any time during hospitalization. BNP decrease was defined as ≥ 30% decrease in the last measured BNP compared to admission. Results Among 760 patients investigated, 95 patients (13%) experienced IRF. Patients with IRF had worse renal function and higher BNP on admission compared to those without IRF (creatinine, 2.04 mg/dl [1.60, 2.52 mg/dl] vs. 1.16 mg/dl [0.90, 1.44 mg/dl], p = 0.004; BNP, 846 ng/l [319, 1465 ng/l] vs. 535 ng/l [232, 1059 ng/l], p = 0.006). Both groups had a significant decrease in BNP ( Figure 1 ), though patients with IRF were less likely to experience a ≥ 30% BNP decrease (37% vs. 55%, p = 0.001). Discharge BNP levels were also higher in those with IRF (664 ng/l [265, 1012 ng/l] vs. 308 ng/l [128, 714 ng/l], p Figure 2 ), though after adjusting for confounders, BNP decrease but not IRF was associated with worse outcomes (IRF, adjusted HR 1.29, 95% CI 0.82-2.02, p = 0.269; BNP decrease, adjusted HR 0.61, 95% CI 0.42-0.89, p = 0.010). Conclusions IRF was associated with severe congestion on admission, insufficient decongestion during hospitalization, and residual congestion at discharge. Decongestion but not IRF was an independent predictor of worse outcomes.