The application of the N-terminal fragment of pro hormone brain natriuretic peptide (NT proBNP) in cardiac disease risk assessment

Abstract

NT proBNP is a precursor peptide that is derived from proBNP a cardiac natriuretic peptide (NP), which is measured in plasma to assist with management of cardiac related conditions. The first aim of this study was to examine the biological variation (BV) of NT proBNP and to calculate its reference change value (RCV) in healthy individuals. The second aim was to assess if the RCV calculated for NT proBNP could be used as prognostic marker in patients who presented with chest pain or acute coronary syndrome (ACS) symptoms at an emergency care unit. A second NT proBNP measurement was performed twenty four hours after admission. These patients were assessed for a likelihood of presenting with three outcomes; probability of mortality; angioplasty or bypass surgery after being monitored for a period of one year. The third aim of the study was to investigate if NT proBNP could be used to identify individuals with possible cardiac conditions for life insurance purpose. NT proBNP assays were measured using the Elecsys 2010 analyser from Roche Diagnostics which uses an electrochemilumeinesence immunoassay that functions on the basis of the sandwich technique. Statistical methods will include analysis of variance and Odd Ratio analysis to assess the risk of a particular outcome. The reference change value (RCV) was calculated as 67%. The odds of requiring angioplasty increased 3.6-fold if a RCV of >67% was observed. The RCV did not aid in predicting mortality, or in predicting need for bypass surgery. A significant association was observed between ECG findings and NT proBNP. The ECG and NT proBNP are not independent of each other in males, as is evident from the correlation between the two variables (r=0.6; p<0.005). This implies that the variables can be used interchangeably. The study concluded that the 67% RCV calculated allows for a more accurate prognostic analysis of each patient and it allows us to move away from the use of population based reference ranges. It was established that a 67% RCV can significantly indicate the likelihood of patients requiring angioplasty. The correlation that was assessed between NT proBNP and the ECG provides insurance companies with the option to choose the method that best accommodates them when assessing cardiac risk.