Is the Measurement of B-Type Natriuretic Peptide in the Emergency Room Useful in Established Congestive Heart Failure Exacerbation?

Introduction: Measurement of natriuretic peptides, particularly brain natriuretic peptide(BNP) has been established as a helpful aid in the diagnosis of heart failure(HF), however, the role of BNP in patients with already well documented HF who present at the Emergency Room(ER) with HF exacerbation is not well understood. Objectives: We sought to evaluate the role of the BNP in patients with documented HF who present to the ER with HF exacerbation. Methods: Retrospective chart review was performed on 443 patients, who presented to the ER with HF exacerbation with previous well documented HF. We compared already established diagnosis criteria for HF with the different BNP levels. Also, the cohort was divided into three groups as follow: BNP!100, BNP 100-400, and BNPO400. Mortality rate and days of hospitalization were compared between the groups. Results: When predicting the outcome of the ER-administered BNP test, there were a number of variables that showed as significant correlation. Normal/Abnormal Previous Echocardiogram: both were correlated with BNP measures(Estimate: -579.0, standard Error: 88.8, p-value !0.05 and -324.8, 93.2, !0.05, respectively), CXR with pleural effusion and/or cardiomegaly both positively correlated with BNP level(368.3, 79.4, !0.05 and 276.4, 67.5, !0.05, respectively) and presenting chief complaint of orthopnea was positively correlated with BNP level(291.2, 64.7, !0.05). A less strong correlation was found between BNP and NYHA classification at presentation(457.9, 182.8, !0.05). The variable of BNP O400 was created and regressed against previous echocardiogram findings, normal echocardiogram mostly yields BNP!400(1.64, 0.37, !0.05), also abnormal echocardiogram mostly yields BNPO400(0.80, 0.38, !0.05) The cohort was divided into three groups as follow: BNP!100, BNP 100400, and BNPO400. No significant difference was noted in the mortality rate between the three groups(p50.08) and no significant difference was noted in the days of hospitalization when comparing the groups(p50.09). Conclusions: Based on our findings, the use of BNP as a diagnostic test for patients with documented HF in the ER does not add any significant value to the information already available from clinical features, CXR and previous echocardiographic findings. Therefore, routine measurement of BNP in patients with established diagnosis of HF does not appear to be useful or cost-effective.