Diagnostic value of lung ultrasound B-line score in acute heart failure

Abstract

To investigate the value of bedside lung ultrasound B-line score in the diagnosis of acute heart failure (AHF). A retrospectively analysis was conducted. The adult patients presenting with acute dyspnea in intensive care unit (ICU) of Affiliated Hospital of Nanjing University of Traditional Chinese Medicine from January 2016 to June 2017 were enrolled. An 8-zone lung ultrasound was performed and plasma B-type natriuretic peptide (BNP) level was tested in all patients. AHF was determined as the final diagnosis by two experienced ICU doctors according to the diagnostic criteria of AHF. Patients were divided into two groups: AHF group and non-AHF group. The levels of BNP and B-line score were compared between the two groups, and the diagnostic value of BNP and B-line score in AHF was evaluated. Fifty-six patients were included in this study, with 32 of men and 24 of women, and with an average age of 77.3±8.8. Thirty-six patients were diagnosed as AHF. The level of BNP and lung ultrasound B-line score in AHF group were higher than those in non-AHF group [BNP (ng/L): 1 640.4±1 078.4 vs. 236.9±124.9, B line score: 12.8±5.3 vs. 5.4±1.8, both P < 0.01]. There was a strong correlation between elevated BNP levels and an increased B-lines score (R2 = 0.712, P = 0.000). The receiver operating characteristic curve (ROC) showed that when the cut-off of lung ultrasound B-line score was 8.5, AHF could be discriminated from dyspnea caused by other diseases (sensitivity was 77.8%, specificity was 95%, positive likelihood ratio was 15.56, negative likelihood ratio was 0.23). The area under the ROC curve (AUC) of lung ultrasound B-line score was 0.917 [95% confidence interval (95%CI) = 0.847-0.987, P = 0.000], slightly lower than that of plasma BNP [0.979 (95%CI = 0.951-1.008)]. Lung ultrasound B-line score was highly specific, but moderately sensitive for identifying patients with AHF.