B-type Natriuretic Peptide in Differentiating Acute Dyspnea

Choi, Han Joo; Hwang, Sung Oh; Jang, Yong Soo; Oh, Sung Bum; Cha, Kyung Cheol; Lee, Seo Young; Kim, Hyun; Lee, Kang Hyun

Abstract

PURPOSE
This study was to test the diagnostic value of Btype natriuretic peptide (BNP) for differentiating between the causes of acute dyspnea.
METHODS
We conducted a prospective study of 41 patients who came to the emergency department with acute dyspnea between August 1, 2002, and October 31, 2002. Plasma BNP was measured for a bedside assay. We excluded patients who suffered from dyspnea due to airway obstruction, hyperventilation syndrome, psychiatric causes, drug intoxication, and chronic renal failure or from dyspnea of neuromuscular origin. The clinical diagnosis of congestive heart failure was adjudicated by echocardiographic findings. Two emergency physicians, who were blinded to the results of the BNP assay and the echocardiographic findings, determined the cause of dyspnea as regard to the Framingham criteria.
RESULTS
The final diagnosis of dyspnea was due to a cardiogenic origin in 29 patients (71%), and due to a noncardiogenic origin in 12 patients (29%). The plasma BNP levels in themselves were more specific and sensitive in diagnosing cardiogenic dyspnea than was a clinical decision based on the authority of the Framingham criteria. In the echocardiographic findings, the left-ventricular end-systolic dimension and the left- ventricular end-diastolic dimension were positively correlated with the plasma BNP levels(R=0.44, p=0.002 and R=0.40, p=0.005), the ejection fraction was negatively correlated (R=-0.46, p=0.001). In the multiple logistic-regression analysis, measurements of the plasma BNP level added significant independent predictive power to other clinical variables in the models.
CONCLUSION
The assay of plasma BNP in the emergency department was useful method for differentiating acute dyspnea based on its cause, and the plasma BNP level was corresponded to the degree of left ventricular dysfunction.