A Cut-off Value Study of N-terminal Brain Natriuretic Peptide （Chemiluminescence Method）

Heart failure (HF) is a complex clinical syndrome characterized by dyspnea, fatigue, and fluid retention (pulmonary congestion, systemic congestion, and peripheral edema) caused by abnormal changes in the structure and/or function of the heart due to multiple causes, resulting in dysfunctional ventricular contraction and/or diastolic function [1]. Heart failure is a severe or advanced stage of various cardiac diseases, with high rates of mortality and rehospitalization [1]. The prevalence of heart failure in developed countries is 1.5%~2.0%, and the prevalence in ≥ 70-year-old population ≥ 10%[2]. According to the epidemiological survey in 2003, the prevalence of heart failure in adults aged 35~74 years in China was 0.9% [3]. In recent years, with the aging of the population, the prevalence of heart failure in China has continued to increase.

A comprehensive and accurate diagnosis is a prerequisite for effective treatment for patients with heart failure, but patients with heart failure often have multiple diseases, and the clinical symptoms of heart failure overlap with those of chronic obstructive pulmonary disease and asthma, making it difficult to make clinical differential diagnosis [1]. At present, a variety of biomarkers have been used in the clinical diagnosis of heart failure, among which brain natriuretic peptide (BNP)/aminoterminal brain natriuretic peptide precursor (NT-proBNP) is the best biomarker for diagnosing heart failure [4].

Natriuretic peptides are a class of endogenous polypeptides with natriuretic and diuretic effects. BNP is an important natriuretic peptide in the human body, which is very sensitive and specifically reflects cardiac dysfunction, and has important clinical significance [5,6]. BNP is mainly synthesized by the ventricles, and when myocardial cells are stimulated, they produce a 134-amino acid B-type natriuretic peptide precursor, followed by a 108-amino acid BNP precursor, which is cleaved by the action of an endonuclease into a 76-amino acid, non-biologically active NT-proBNP, and a 32-amino acid-containing active BNP, which are released into the bloodstream [6].

Currently, blood BNP levels have been recommended by several international authoritative societies, including the American College of Cardiology Foundation/American Heart Association (ACCF/AHA), and the European Society of Cardiology (ESC), as a diagnostic and prognostic indicator of heart failure [7-10].

NT-proBNP and BNP belong to the same natriuretic peptide family and have the same biological origin. Because NT-proBNP and BNP are equimolar releases, they have similar clinical applications in the diagnosis, treatment, monitoring, and prognosis of cardiovascular diseases [5].