The purpose of this study is to compare the changes in B-type Natriuretic Peptide (BNP) and amino-terminal fragment of proBNP (NT-proBNP) in outpatients managed in the heart failure (HF) clinic initiated on the Angiotensin Receptor Neprilysin Inhibitor (Entresto) and directly compare the prognostic values of BNP and NT-proBNP in patients admitted with acute decompensated HF.

Both natriuretic peptides (NP), namely B-type NP (BNP) and amino-terminal fragment of proBNP (NT-proBNP), have an established role in the management of patients with heart failure (HF).[1] However, the clinical utility of BNP has recently been questioned with the PARADIGM-HF trial, which demonstrated increased BNP and reduced NT-proBNP levels following the administration of Entresto, a newly approved angiotensin receptor neprilysin inhibitor (ARNI).[2.3] The increase in BNP was thought to be reflective of reduced metabolism of BNP as a result of neprilysin inhibition.[2] However, this claim was based on observations of three points in time and with wide confidence intervals.[3] In addition, there has been no attempt to demonstrate dose relationships. Furthermore, although both BNP and NT-proBNP have each been shown to predict HF readmission in hospitalized patients [1,4,5] the relative utility between the two NPs for this prediction remains unclear. We therefore hypothesize that once beyond the initiation of ARNI therapy, BNP and NT-proBNP will be equally predictive of clinical events in patients with HF.

The studies comprise of two separate protocols:

A. Outpatient Protocol - the effect of Entresto measuring the changes in the NT-proBNP and BNP test results. This protocol will be conducted on ambulatory outpatients initiating on Entresto. Patients will have blood sampling for the measurements of BNP and NT-proBNP at baseline, at the first and second up titration in dose of Entresto, and at 6 months and 1st year after starting Entresto.

B. Inpatient Protocol-predicting outcomes. This will be conducted on patients admitted for acute decompensated HF. Blood sampling for BNP and NT-proBNP will be collected in different time points (admission, hospital discharge, 30th day, 90th day, and 180th day) and measure its changes.

Inclusion Criteria:

Out Patient Protocol - Patients with chronic heart failure being followed in the heart failure clinic eligible to switch angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) to ARNI (Entresto).

In Patient Protocol - Patients admitted due to acute decompensated heart failure