Correlation between chest x-ray and B-type natriuretic peptide in congestive heart failure

Introduction B-Type natriuretic peptide (BNP) values greater than 400 pg/mL have high positive likelihood ratio (>10) for the diagnosis of clinical congestive heart failure (CHF). However, in patients with CHF, it is not known what correlation, if any, exists for the BNP levels above 400 pg/mL and the findings on the initial chest x-ray (CXR). Methods Retrospective review of emergency department patients with CHF and initial BNP greater than 400 pg/mL. Descriptive statistics were analyzed and logistic regression was performed. Results Fifty-four patients mean age of 81.7 (SD, 8.2), 64.8% women. The mean BNP was 1493 pg/mL (SD, 1106). Only 68.5% had a finding of CHF on CXR. Logistic regression showed no correlation (Wald P = .568; R2 = 0.8%). Conclusion In patients with clinical CHF, there is no correlation between very high BNP levels (>400 pg/mL) and CXR readings. Clinicians should not be surprised to find patients with very high BNP levels but negative CXR.