Heart failure (HF) is a complex clinical syndrome affecting 6.2 million people in the United States [1]. The diagnosis of heart failure is challenging as patients usually present non-specific symptoms, which are often shared by other diseases. Both B-type natriuretic peptide (BNP) and the N-terminal pro BNP (NT-proBNP) are widely used as biomarkers to diagnose heart failure and assess a patient’s response to therapy. Cardiomyocytes secrete proBNP in response to myocardial wall stretch, which is further cleaved into two circulating fragments; C-terminal B-type NP (BNP), a biologically active fragment and N-terminal proBNP (NT-proBNP), biologically inactive fragment [2].
NT-proBNP
For treating heart failure, a new FDA approved drug called Entresto is commonly used, which disrupts the levels of BNP [3]. To resolve this issue, NT-proBNP can be used as a biomarker for diagnosis and prognosis in patients treated with Entresto [4]. The pharmacodynamic studies revealed that Entresto increased the plasma levels of BNP, while decreased the plasma levels of NT-proBNP. These increased BNP levels may lead to misinterpretations in the response of patients after treatment with Entresto [5]. Thus NT-proBNP is a better biomarker than BNP. In order to distinguish normal NT-proBNP from the pathological one, different classification systems are used. The classification system provided by the European Society of Cardiology is based on a cut‐off level of 125 ng/L for NT-proBNP in case of chronic heart failure [6]. The classification system provided by Stämpfli et al. is based on age and gender [7]. Clinical Chemistry and Laboratory Medicine use a classification system according to the manufacturer’s instructions [8].
Advantages of NT-proBNP VS BNP
The production of ventricular NT-proBNP has been reported to be upregulated in cardiac failure and localized in the area of myocardial infarct. Half-life and the plasma levels of NT-proBNP is higher than BNP, which may provide a better diagnostic value [9]. Moreover, NT-proBNP is a more stable specimen for diagnosis purposes as it is less likely to degrade in vitro and in vivo [10]. Whereas, BNP has shown less stability in the in vitro studies [11]. All NT-proBNP diagnostic tests are harmonized to the Roche method in contrast to BNP tests, which utilize many targets and antibodies. The BNP testing is not harmonized to a single method, thus yielding different results [12]. NT-proBNP has also shown good results in predicting morbidity, mortality, and hospitalization for HF as compared to BNP [13]. In addition, NT-proBNP has better accuracy in identifying mild HF than BNP [14].
In the past, BNP was the only diagnostic tool for acute HF and ventricular dysfunction [15]. High levels of BNP also act as a predictor for thromboembolism in patients with pulmonary embolism [16]. However, recent developments in research reported the production of NT-proBNP also from the atrial wall upon myocardial stretch [17]. Atrial fibrillation (AF) is associated with alterations in atrial muscle tone, and may lead to generate changes in the production of NT-proBNP. Thus, NT-proBNP can also be used as a risk factor of atrial fibrillation with or without left atrial enlargement [18]. High levels of NT-proBNP are used to distinguish cardiac from the pulmonary causes of acute HF [19], predict short-term and long-term cardiovascular mortality and ischemic recurrence [20], and also used to assess the severity of chronic HF [21]. Levels of NT-proBNP are also used as an effective indicators in predicting cardiac events in elderly chronic heart failure (CHF) and have a clinical significance in evaluating disease severity and prognosis. NT-proBNP detection has a significant role in evaluating CHF in elderly patients [22]. As the plasma level of NT-proBNP is not affected by the medication, thus it has been concluded that NT-proBNP is a better natriuretic biomarker than BNP for HF diagnosis and prognosis.
The RAMP® NT-proBNP test is used in diagnosis and assessment of severity in patients with chronic heart failure.
REFERENCES
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