Around 5.1 million patients in the US have HF, the estimated cost of HF to the economy is estimated to be around $30.7 billion dollars a year.1 Even though the past few decades have seen significant advances in the understanding of the HF syndrome, patients with chronic HF have still an adverse prognosis overtime. In the last decade serum NT-proBNP has emerged as a widely used biomarker in HF. The N-terminal prohormone of brain natriuretic peptide (NT-proBNP) is a prohormone with a 76 amino acid N-terminal inactive protein that is cleaved from the molecule to release brain natriuretic peptide.^2,3 It is secreted by cardiac myocytes in response to bio-mechanical stress.

Numerous studies have evaluated ”point in time” measurements of NT-proBNP. Higher NT-proBNP levels are clearly associated with a prognosis in acute and chronic HF (both HFPeF and HFReF).¹ There has been considerable enthusiasm and controversy around using NTpro-BNP levels to guide the management of HF^1,2. This biomarker strategy relies on a better understanding of the association of temporal trends in NTpro-BNP levels in patients and clinical outcomes ^1,2. Serial assessment of NP in HF has revealed that changes in NP concentrations over time parallels clinical outcomes both in patients with chronic HF and acute decompensated heart failure.^3,4,5. However, it is unclear whether this holds true in patients with both subsets of HF- HpEF(left ventricular ejection fraction (LVEF) > 50%) and HFrEF (left ventricular ejection fraction (LVEF) < 40%)⁶.

Some investigators have suggested that the association of temporal trends in NT-proBNP levels and clinical outcomes (that is observed in HFrEF) may not be observed in patients with HFpEF, partly because there may be significant difference in the kinetics of NT-proBNP in HFpEF and HFrEF. ^6,7 NT-proBNP levels in patients with HFpEF have been shown to have a significantly higher short-term “intra-day” fluctuation than in patients HFrEF, without any discernible change in clinical status.⁷ This suggests that longer term trends in NT-proBNP levels in HFpEF patients, may not be as tightly associated with clinical outcomes as in HFrEF.

We conducted this retrospective study to investigate whether temporal trends in NT-pro-BNP levels were associated with mortality in both HFpEF and/or HFrEF. We had the following hypothesis; Rising NT-proBNP levels would be associated with a lower six-month survival in both the echocardiographically defined subsets of HF (HFpEF and HFrEF) after adjusting for other clinically relevant co-variates.