Accepted Manuscript
Prognostic Value and Kinetics of Soluble Neprilysin in Acute Heart Failure. A Pilot
Study
Antoni Bayes-Genis, MD, PhD, Jaume Barallat, MD, Domingo Pascual, MD, PhD,
Julio Nuñez, MD, PhD, Gema Miñana, MD, Jesús Sánchez-Mas, PhD, Amparo
Galan, MD, PhD, Juan Sanchis, MD, PhD, Elisabet Zamora, MD, PhD, María Teresa
Pérez-Martínez, MD, Josep Lupón, MD, PhD
PII:
S2213-1779(15)00266-8
DOI:
10.1016/j.jchf.2015.03.006
Reference:
JCHF 306
To appear in:
JACC: Heart Failure
Received Date: 6 February 2015
Revised Date:
25 February 2015
Accepted Date: 9 March 2015
Please cite this article as: Bayes-Genis A, Barallat J, Pascual D, Nuñez J, Miñana G, Sánchez-Mas
J, Galan A, Sanchis J, Zamora E, Pérez-Martínez MT, Lupón J, Prognostic Value and Kinetics of
Soluble Neprilysin in Acute Heart Failure. A Pilot Study, JACC: Heart Failure (2015), doi: 10.1016/
j.jchf.2015.03.006.
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Prognostic Value and Kinetics of Soluble Neprilysin in Acute Heart Failure.
A Pilot Study
Antoni Bayes-Genis, MD, PhD1,3, Jaume Barallat, MD2, Domingo Pascual, MD, PhD4, Julio
Nuñez, MD, PhD5,7, Gema Miñana, MD8, Jesús Sánchez-Mas, PhD4, Amparo Galan, MD,
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PhD2, Juan Sanchis, MD, PhD6,7,Elisabet Zamora, MD, PhD1,3, María Teresa Pérez-Martínez,
MD4, Josep Lupón, MD, PhD1,3
From: 1Cardiology Service and Heart Failure Unit, and 2Biochemistry Service, Hospital
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Universitari Germans Trias i Pujol, Badalona, Spain. 3Department of Medicine, Autonomous
University of Barcelona, Barcelona, Spain. 4Cardiology Department, Hospital Virgen de la
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Arrixaca, Department of Medicine, University of Murcia, Murcia, Spain. 5Biochemistry and
Cardiology Services, Hospital Clínico Universitario. Valencia,Spain. 7University of
Valencia.8Cardiology Service, Hospital de Manises. Valencia,Spain
Short Title: sNEP in acute HF
Corresponding Author:
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List of disclosures: Nothing to declare
Antoni Bayes-Genis, MD, PhD, FESC, FHFA
Cardiology Service. Hospital Universitari Germans Trias i Pujol.
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Carretera de Canyet s/n 08916. Badalona (Barcelona).
E-mail: [email protected]
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Telephone +34 93 497 86 62; Fax +34 93 497 89 39
ACKNOWLEDGMENTS
We wish to thank the nurses in the HF units for collecting the data and for their invaluable
work. We also wish to acknowledge the research network Red de Investigación
Cardiovascular (RD12/0042/0047, RD12/0042/0049 and RD12/0042/0010).
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ABSTRACT
Background: The soluble form of neprilysin (sNEP) was recently identified in chronic heart
failure (HF) and associated with cardiovascular outcomes.
Objectives: To examine the prognostic value of sNEP in acute HF (AHF) and sNEP kinetics
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during hospital admission.
Methods: A total of 350 patients (53% women, mean age 72.6 ± 10.7 years) were included in
the study. Primary endpoints were a composite of cardiovascular death or heart failure
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hospitalizations at short-term (2 months) and long-term (mean 1.8 ± 1.2 years) follow-up.
sNEP was measured using an ad hoc modified ELISA assay and its prognostic value assessed
admission and discharge (n=92).
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using Cox regression analyses. In a subgroup of patients sNEP was measured both at
Results: Median admission sNEP levels were 0.67 ng/ml (Q1-Q3 0.37-1.29), and sNEP was
significantly associated, in age-adjusted Cox regression analyses, with the composite
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endpoint at short-term (hazard ratio [HR] 1.29, 95% confidence interval [CI] 1.04-1.61,
p=0.02) and long-term follow-up (HR 1.23, 95% CI 1.01-1.05, p=0.003). In multivariable
Cox analyses that included clinical variables and N-terminal pro-brain natriuretic peptide
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(NTproBNP), admission sNEP showed a clear trend towards significance for the composite
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endpoint at 2 months (HR 1.22, 95% CI 0.97-1.53, p=0.09) and remained significant at the
end of follow-up (HR 1.21, 95% CI 1.04-1.40, p=0.01). At discharge, sNEP levels decreased
from 0.70 to 0.52 ng/ml (p=0.06).
Conclusions: Admission sNEP was associated with short- and long-term outcomes in AHF
and dynamic sNEP concentrations were observed during hospital admission. These
preliminary data may be hypothesis generating for the use of NEP inhibitors in AHF.
Key words: Neprilysin, acute heart failure, prognosis
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CONDENSED ABSTRACT
The soluble form of neprilysin (sNEP) was recently identified in chronic heart failure (HF)
and associated with cardiovascular outcomes. We examined the prognostic value of sNEP in
acute HF in 350 patients and sNEP kinetics during hospital admission in 92 patients. Primary
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endpoints were a composite of cardiovascular death or HF hospitalizations at short-term (2
months) and long-term (mean 1.8 ± 1.2 years) follow-up. sNEP was significantly associated,
in age-adjusted Cox regression analyses, with the composite endpoint at short-term and long-
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term follow-up. In those patients with sNEP available at discharge, sNEP levels decreased
from 0.70 to 0.52 ng/ml.
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ABREVIATION LIST
NEP: Neprilysin
HF: Heart failure
AHF: Acute heart failure
CV: Cardiovascular
HR: Hazard ratio
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ARNi: angiotensin receptor neprilysin inhibitor
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NT-proBNP: N-terminal pro-B type natriuretic peptide
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LVEF: Left ventricular ejection fraction
SD: Standard deviation
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The enzyme neprilysin (NEP) plays a central role in neurohormonal regulation in heart
failure (HF) by breaking down a plethora of vasoactive peptides (1). The extracellular domain
of NEP was identified recently in ambulatory chronic HF patients as a circulating soluble
form of NEP (sNEP) (2). In a large, real-life, consecutive cohort of 1,069 patients with long-
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term follow-up, sNEP was found to be a good pathobiological surrogate of cardiovascular
mortality and morbidity (2).
In acute HF (AHF) a multitude of regulatory and counter-regulatory neurohormonal
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axes are acutely over-expressed (3), but no evidence is available on sNEP concentrations in
AHF. Therefore, this pilot multicentre study aimed to identify the levels and prognostic value
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of sNEP in AHF and the sNEP kinetics during hospital admission.
From May 2008 to December 2013, 350 patients (mean age 72.6±10.7 years) admitted
for AHF were consecutively included in the study. Inclusion criteria and blood sample
collection have been described elsewhere (4,5). All participants provided written informed
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consent, and the local ethics committees approved the study. Primary outcomes were a
composite of cardiovascular death or HF hospitalization at 2 months and at the end of followup.
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Human NEP was measured using a modified sandwich immunoassay (HUMAN
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NEP/CD10 ELISA KIT, Aviscera Biosciences, Santa Clara, USA, Ref. SK00724-01, Lot No.
20112070) with previously reported ad hoc modifications to improve the analytical
sensitivity of the method (2). The intra- and inter-assay coefficients of variation were 3.7%
and 8.9%, respectively.
Categorical variables were expressed as percentages. Continuous variables were
expressed as means (standard deviation [SD]) or medians (quartile Q1-Q3) according to
normal or non-normal distributions. Normal distribution was assessed with normal Q-Q plots.
The sNEP and N-terminal pro-brain natriuretic peptide (NTproBNP) values were log-
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transformed and 1 standard deviation (SD) used to calculate the hazard ratio (HR). Cox
regression analyses including sNEP with age as a covariate and multivariable Cox regression
analyses were performed.
The clinical characteristics of patients are shown in Table 1. The median sNEP level
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was 0.67 ng/ml (Q1-Q3 0.37-1.29). At 2 months, 60 composite endpoints, 28 cardiovascular
deaths, and 36 HF re-hospitalizations had occurred. At the end of follow-up (mean 1.8 ± 1.2
years), 158 composite endpoints, 81 cardiovascular deaths, and 120 HF re-hospitalizations
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had occurred. As a continuous variable in age-adjusted Cox regression analyses, sNEP
concentration was significantly associated with the composite endpoint at 2 months (HR 1.29,
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95% confidence interval [CI] 1.04-1.61, p=0.02) and at the end of follow-up (HR 1.23, 95%
CI 1.01-1.05, p=0.003). The sNEP level was also associated with cardiovascular death at 2
months (HR 1.38, 95% CI 1.01-1.88, p=0.04). Figure 1 depicts the survival-free event curves
for the composite endpoint at 2 months (A) and long-term follow-up (B) for patients with
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sNEP levels below or above the median.
In a multivariable Cox regression analyses that included clinical variables (age, sex,
ischemic etiology of HF, left ventricular ejection fraction, hemoglobin, creatinine) and
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NTproBNP, sNEP showed a clear trend towards significance for the composite endpoint at 2
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months (HR 1.22, 95% CI 0.97-1.53, p=0.09). In the long-term follow-up analysis, if
treatment was not incorporated in the model, both sNEP and NTproBNP were independent
predictors of the composite endpoint (p=0.015 and p=0.006, respectively). However, when
treatment with beta-blockers, angiotensin-converting enzyme inhibitors/angiotensin II
receptor blockers, and mineralcorticoid receptor antagonists was also incorporated into the
model; sNEP remained significant at the end of follow-up (HR 1.21, 95% CI 1.04-1.40,
p=0.01), but NTproBNP lost its prognostic significance for the combined end-point (HR
1.19, 95% CI 0.96-1.47, p=0.12).
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In a small sample of 92 patients, sNEP was also measured at discharge. In these
patients, the median value decreased from 0.70 ng/ml at admission to 0.52 ng/ml at discharge
(p=0.06). We did not find significant differences between patients with and without sNEP
reduction relative to age, sex, LVEF, ischemic etiology, treatment during admission, number
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of hospitalization days, nor initial NTproBNP and sNEP concentrations; nevertheless, sNEP
reduction tended to be more frequent in non-ischemic patients (62% vs. 42% in ischemic
patients, p=0.06). In the subgroup of patients with serial sNEP, HR for outcomes at 60 days
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were 0.70 (95%CI 0.22 to 2.33) and 0.55 (95%CI 0.91 to 3.27) for the composite end-point
and CV death, respectively; although in the good direction, in both cases the p-values were
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non-significant very likely due to the limited number of events.
Assessing risk in the context of AHF is a challenging proposal. Currently, natriuretic
peptides are state-of-the-art prognostic biomarkers in AHF patients (6). However, the use of
biomarkers beyond natriuretic peptides for risk assessment in patients with AHF is under
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examination. Here, we provide evidence for sNEP as a novel prognostic biomarker in AHF in
both the short- and the long-term. Indeed, NEP is responsible for the break-down of a
plethora of vasoactive neurohormones activated in AHF, including natriuretic peptides.
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Remarkably, in long term follow-up, sNEP levels, reflective of comprehensive
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neurohormonal activation, remained strongly significant for the combined end-point, whereas
NTproBNP, which is only reflective of the natriuretic peptide axis, lost significance.
The dynamic behaviour of sNEP observed in the setting of AHF is similar to that of
other biomarkers, such as natriuretic peptides and ST2. The decreased sNEP levels as the
clinical status stabilizes may mirror the return to quiescence of the acutely activated
neurohormonal axes. In our chronic HF cohort we found a median sNEP concentration of
0.64 ng/ml (2), lower than that found in the present AHF cohort. Although the subsample
with sNEP kinetics was small, a reduction with stability is clearly suggested, observation that
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conforms to the lower sNEP concentration found in chronic patients. Additional studies
beyond the scope of the present report are needed to address whether sNEP kinetics respond
to specific therapeutic strategies.
NEP inhibition may become mainstream during 2015 as LCZ696 is approved by
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regulatory agencies. The results of the Prospective comparison of ARNI with ACEI to
Determine Impact on Global Mortality and morbidity in Heart Failure trial (PARADIGMHF) Trial indicate that chronic ambulatory HF patients are candidates for replacement of
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enalapril by LCZ696 (7), but what to do in AHF in the post-PARADIGM era is uncertain.
Some argue that LCZ696 should be initiated as soon as possible during hospital admission,
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whereas others argue that hospitalized patients should receive enalapril first. Our data provide
a better understanding of sNEP in AHF and may be hypothesis generating for the use of NEP
inhibitors in AHF.
As main limitations we have to acknowledge that the sample size is limited to draw
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definitive conclusions, and also that we have no data on sNEP stability while frozen so we
cannot discard that sNEP concentration would have been different in fresh samples.
In summary, this pilot multicentre study suggests that admission sNEP levels are
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associated with short- and long-term outcomes in AHF, and that sNEP concentrations are
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dynamic during hospital admission. These preliminary data may argue in favour of NEP
inhibitor use in AHF.
Perspectives
COMPETENCY IN MEDICAL KNOWLEDGE: Neprilysin is a crucial enzyme that
breaks down a multitude of vasoactive peptides in patients with HF, and inhibition of
neprilysin as a therapeutic target is associated with reductions in cardiovascular morbidity
and mortality.
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TRANSLATIONAL OUTLOOK: Prospective trials are needed to assess whether neprilysin
inhibition based on measurements of plasma neprilysin levels in patients with acute HF is
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clinically useful.
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REFERENCES
1. Erdos EG, Skidgel RA. Neutral endopeptidase 24.11 (enkephalinase) and related
regulators of peptide hormones. FASEB J 1989;3:145–51
2. Bayes-Genis A, Barallat J, Galan A, et al. Soluble Neprilysin is Predictive of
Am Coll Cardiol 2015;65:657–65.
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Cardiovascular Death and Heart Failure Hospitalization in Heart Failure Patients. J
3. Bayes-Genis A, Santaló-Bel M, Zapico-Muñiz E, et al. N-terminal probrain natriuretic
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peptide (NT-proBNP) in the emergency diagnosis and in-hospital monitoring of
patients with dyspnoea and ventricular dysfunction. Eur J Heart Fail. 2004;6:301-8.
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4. Pascual-Figal DA, Bonaque JC, Manzano-Fernández S, et al. Red blood cell
distribution width predicts new-onset anemia in heart failure patients. Int J Cardiol
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5. Bonanad C, Núñez J, Sanchis J, et al. Serum heat shock protein 60 in acute heart
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failure: a new biomarker? Congest Heart Fail. 2013;19:6-10.
6. Januzzi JL, van Kimmenade R, Lainchbury J, et al. NT-proBNP testing for diagnosis
and short-term prognosis in acute destabilized heart failure: an international pooled
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analysis of 1256 patients: the International Collaborative of NT-proBNP Study. Eur
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Heart J 2006; 27:330–337.
7. McMurray JJ, Packer M, Desai AS, et al; PARADIGM-HF Investigators and
Committees. Angiotensin-neprilysin inhibition versus enalapril in heart failure. N
Engl J Med. 2014;371:993-1004.
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FIGURE LEGEND
Figure 1.
Cox Regression event-free survival curves for the composite end-point at 2
months (A) and long-term follow-up (B). Age was included as a covariate and
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the median value of NEP was 0.67ng/ml.
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Table 1.
Demographic and clinical characteristics at baseline and treatments during followup
Total Cohort
N= 350
*
72.6 ± 10.7
Female, n (%)
186 (53.1)
Ischemic etiology of HF, n (%)
132 (37.7)
LVEF, in %*
46.6 ± 16.2
Creatinine, mg/dl*
1.26 ± 0.6
Hemoglobin, g/dl*
12.2 ± 2.1
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NT-proBNP ng/l†
3953 (1988–8155)
†
0.67 (0.37-1.29)
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Neprilysin, ng/ml
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Age, yr
*Mean ± standard deviation; †Median (Q1-Q3). HF, heart failure; LVEF, left ventricular
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ejection fraction; NT-proBNP, N-terminal pro-brain natriuretic peptide.
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