Neprilysin

Soluble neprilysin and long-term clinical outcomes in patients with coronary artery disease undergoing percutaneous coronary intervention: a retrospective cohort study

Background

Neprilysin has an essential role in regulating fluid balance and vascular resistance, and neprilysin inhibitors have shown beneficial effects in patients with heart failure. However, the potential predictive value of neprilysin levels as a biomarker for cardiovascular risk remains unclear. The aim of this study was to assess the prognostic value of soluble neprilysin (sNEP) levels in patients with ischemic heart disease.

Methods

Neprilysin levels were measured in 694 consecutive patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI). These patients were classified into two groups according to their serum levels of neprilysin and categorized into the lower neprilysin group (n = 348) and the higher neprilysin group (n = 346). The primary clinical endpoint was all-cause mortality, and the secondary endpoint was a composite of major adverse cardiac events (MACE).

Results

The median sNEP level was 76.0 pg/ml. The median sNEP levels were higher in patients with left ventricular ejection fraction (LVEF) ≥40% (77.6 pg/ml, interquartile range 46.6–141.3) than in those with LVEF < 40% (70.0 pg/ml, interquartile range 47.1–100.6; P = 0.032). Among all patients, each clinical outcome and MACE did not differ significantly according to the groups divided into median, tertile, or quartile of sNEP levels during a median follow-up of 28.4 months. We did not find a significant relationship between sNEP levels and clinical outcomes in multivariate Cox regression analysis. Among patients with LVEF < 40%, an increased sNEP level was associated with a higher rate of all-cause death (adjusted hazard ratio 2.630, 95% confidence interval 1.049–6.595, P = 0.039).

Conclusion

Serum sNEP levels are not associated with long-term mortality or cardiovascular outcomes after PCI in patients with CAD. In the LVEF < 40% group, increased sNEP levels may be associated with a higher risk of all-cause death.

Neutral Endopeptidase (Neprilysin) in Therapy and Diagnostics: Yin and Yang

Neprilysin (NEP) is a zinc-dependent metalloproteinase that exists in organisms in both transmembrane and soluble forms. NEP substrates are involved in regulating the cardiovascular and nervous systems. In this review, we discuss some of the biochemical characteristics and physiological functions of this enzyme with special emphasis on the use of NEP as a therapeutic target. The history and various physiological aspects of applying NEP inhibitors for treating heart failure and attempts to increase NEP activity when treating Alzheimer's disease using gene and cell therapies are described. Another important issue discussed is the role of NEP as a potential marker for predicting the risk of cardiovascular disease complications. The diagnostic and prognostic performance of soluble NEP in various types of heart failure is analyzed and presented. We also discuss the methods and approaches for measuring NEP activity for prognosis and diagnosis, as well as a possible new role of natriuretic peptides (NEP substrates) in cardiovascular diagnostics.

Soluble Neprilysin ― Cardiac Function and Outcome in Hypertrophic Cardiomyopathy ―

Background: Circulating soluble neprilysin (sNEP) predicts outcome in heart failure (HF) patients with reduced ejection fraction (EF), but not in those with preserved EF. We examined sNEP in patients with hypertrophic cardiomyopathy (HCM), and their correlations with other biomarkers, cardiac function, and clinical outcome.

Methods and Results: We examined the associations between sNEP and the laboratory and echocardiography parameters in the HCM patients (n=93). Regarding the laboratory data, sNEP had a significant positive correlation with B-type natriuretic peptide (BNP; R=0.326, P=0.003), but not with troponin I. As for the echocardiographic parameters, sNEP negatively correlated with left ventricular EF (R=−0.283, P=0.009) and right ventricular fractional area change (R=−0.277, P=0.012), but not with left ventricular mass. Next, we prospectively followed up on the patients for cardiac events, including worsening HF or cardiac death, and all-cause mortality. On Kaplan-Meier analysis (mean follow-up, 1,021 days), the cardiac event rate and all-cause mortality were similar between the higher sNEP group (sNEP ≥median level of 1.43 ng/mL, n=46) and lower sNEP group (sNEP <1.43 ng/mL, n=47). On Cox proportional hazard analysis, sNEP was not a predictor of cardiac event or all-cause mortality.

Conclusions: Soluble neprilysin appears to correlate with BNP and cardiac systolic function, but it is not significantly associated with prognosis in HCM patients.

Natriuretic peptide family as diagnostic/prognostic biomarker and treatment modality in management of adult and geriatric patients with heart failure: remaining issues and challenges

B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP), the key members of natriuretic peptide family have been recommended as the gold standard biomarkers for the diagnosis and prognosis of heart failure (HF) according to the current clinical guidelines. However, recent studies have revealed many previously unrecognized features about the natriuretic peptide family, including more accurate utilization of BNP and NT-proBNP in diagnosing HF. The pathophysiological mechanisms behind natriuretic peptide release, breakdown, and clearance are very complex and the diverse nature of circulating natriuretic peptides and fragments makes analytical detection particularly challenging. In addition, a new class of drug therapy, which works via natriuretic peptide family, has also been considered promising for cardiology application. Under this context, our present mini-review aims at providing a critical analysis on these new progresses on BNP and NT-proBNP with a special emphasis on their use in geriatric cardiology settings. We have focused on several remaining issues and challenges regarding the clinical utilization of BNP and NT-proBNP, which include: (1) Different prevalence and diagnostic/prognostic values of BNP isoforms; (2) methodological issues on detection of BNP; (3) glycosylation of proBNP and its effect on biomarker testing; (4) specificity and comparability of BNP/NT-proBNP resulted from different testing platforms; (5) new development of natriuretic peptides as HF treatment modality; (6) BNP paradox in HF; and (7) special considerations of using BNP/NT-proBNP in elderly HF patients. These practical discussions on BNP/NT-proBNP may be instrumental for the healthcare providers in critically interpreting laboratory results and effective management of the HF patients.

Management of suspected acute heart failure dyspnea in the emergency department: results from the French prospective multicenter DeFSSICA survey

BACKGROUND

An appropriate diagnostic process is crucial for managing patients with acute heart failure (AHF) in emergency department (ED). Our study aims to describe the characteristics and therapeutic management of patients admitted to the ED for dyspnea suspected to have AHF, their in-hospital pathway of care and their in-hospital outcome.

METHODS

Consecutive patients admitted in 26 French ED for dyspnea suspected to be the consequence of AHF, prior to in hospital diagnostic test, were prospectively included at the time of their admission in the DeFSSICA Survey. Clinical characteristics at admission were recorded by the ED physicians. At discharge from ED, patients were categorized as AHF or non-AHF based on the final diagnosis reported in the discharge summary. The completeness of the data was controlled by the local investigator.

RESULTS

From 16/6/2014 to 7/7/2014, 699 patients were included, of whom 537 (77 %) had a final diagnosis of AHF at discharge. Patients with AHF were older (median 83 vs 79 years, p = 0.0007), more likely to have hypertension (71 % vs 57 %, p = 0.002), chronic HF (54 % vs 37 %, p = 0.0004), atrial fibrillation (45 % vs 34 %, p = 0.02) and history of hospitalization for AHF in the previous year (40 % vs 18 %, p < 0.0001) when compared to patients without AHF. Furosemide and oxygen were used in approximately 2/3 of the patients in the ED (respectively 75 and 68 %) whereas nitrates were in 19 % of the patients. Diagnostic methods used to confirm AHF included biochemistry (100 %), pro-B-type natriuretic peptide (90 %), electrocardiography (98 %), chest X-ray (94 %), and echography (15 %) which only 18 % of lung ultrasound. After the ED visit, 13 % of AHF patients were transferred to the intensive care unit, 28 % in cardiology units and 12 % in geriatric units. In-hospital mortality was lower in AHF vs non-AHF patients (5.6 % vs 14 %, p = 0.003).

DISCUSSION

DeFSSICA, a large French observational survey of acute HF, provides information on HF presentation and the French pathway of care. Patients in DeFSSICA were elderly, with a median age of 83 years. Compared with the French OFICA study, patients in DeFSSICA were more likely to have hypertension (71 % vs 62 %) and atrial fibrillation (45 % vs 38 %). As atrial fibrillation and a rapid heart rate have been closely linked to mortality, detection of atrial fibrillation should be considered systematically.The limited use of nitrates in DeFSSICA may be related to the median SBP of 140 (121-160) mmHg. However, our use of nitrates was similar to those in the EAHFE (20.7 %) and OPTIMIZE-HF (14.3 %) registries. In line with guidelines, the proportions of patients who underwent ECG, biological analysis, or chest X-ray were all >90 % in DeFSSICA. Similarly, BNP or pro-BNP was measured in 93 % of patients, compared with 82 % of patients in the OFICA study. Although BNP may be helpful when the diagnosis of HF is in doubt, ultrasound remains the gold standard. The use of ultrasound in the ED has been reported to accelerate the diagnosis of HF and the initiation of treatment, and shorten the length of stay. In-hospital mortality of HF patients in DeFSSICA was 6.4 %, slightly lower than in the OFICA study (8.2 %). Improved interdisciplinary cooperation has been highlighted as a key factor for the improvement of HF patient care.

CONCLUSIONS

DeFSSICA shows that patients admitted for dyspnea suspected to be the consequence of AHF are mostly elderly. The diagnosis of AHF is difficult to ascertain based on clinical presentation in patients with dyspnea. Novel diagnostic techniques such as thoracic ultrasound are warranted to provide the right treatment to the right patients in the ED as early as possible.