Cardiovascular natriuretic peptides in emergency

Natriuretic peptides have emerged as important candidates for development of diagnostic tools in cardiovascular disease being the establishment of the cause of shortness of breath in the acute setting (Emergency Department) one of most interesting clinical application. In fact, the measurement of plasma cardiac natriuretic peptides and, in particular, BNP or NT-proBNP which are secreted by the heart in response to increases in trasmural pressure, is useful to differentiate dyspnea due to cardiac involvement from dyspnea related to other factors. In our experience, carried out by evaluating the NT-proBNP measurement in a population of 122 patients presenting at ED with acute-severe dyspnea, we observed a statistically significant difference( p = 0.05) in values measured in patients showing a dyspnea of cardiac origin (50° percentile 3509 ng/l) in comparison to those of pulmonary (50° percentile 259.70 ng/l) as well as of other factors origin (50°percentile 539 ng/l). At 1760 ng/l, the best cut-off calculated from ROC analysis (AUC ± SE 0.815 ± 0.041), the accuracy of test in identifying the cardiac origin of dyspnea was 0.78, being 0.78 and 0.79 the positive predictive value and negative predictive value, respectively. Comparing NT-proBNP values and ED diagnosis, a disagreement in 24 patients was observed. Using the discharge diagnosis as “gold standard”, four cases (17%) were found to be False Positive (FP) and 11 cases (46%) were False Negative (FN) considering ED diagnosis, while 2 patients showed FP and 7 FN NT-proBNP values. NT-proBNP measurement represents a useful biochemical tool helping ED physician in the rapid and reliable recognition of the cardiac involvement in patients presenting at ED with acute-severe dyspnea, allowing a better and faster therapeutic treatment of patients as well as a reduction in unnecessary admissions that may help to justify the costs for implementing a new biochemical tools in this particular clinical setting.