Predictors of B-line count in hospitalized patients with COVID-19

Abstract Background B-lines on lung ultrasound (LUS) are non-specific signs of increased density within lung tissue, which can be secondary to pulmonary congestion, pneumonia, or fibrosis. LUS is recommended for managing acute heart failure (HF); however, its value in non-HF populations is less clear. Purpose To identify clinical, laboratory, and echocardiographic predictors of B-lines in a population with Coronavirus disease 2019 (COVID-19). Methods In the ECHOVID-19 study, hospitalized non-ICU patients ≥18 years with confirmed laboratory diagnosis of COVID-19 in Eastern Denmark underwent 8-zone LUS and echocardiography. We used trend and regression analyses to identify associations with the number of B-lines and adjusted for potential confounders (age, sex, body mass index, C-reactive protein, and pandemic wave). Results Among 270 (89%) patients with adequate LUS images, the mean age was 69±14 years, 58% were male and 11% had prior HF. Median time from hospital admission to LUS was 4 [2-8] days. In total, 263 (97%) had ≥1 B-line (median B-line number 14 [9-22]) and median left ventricular ejection fraction [LVEF] was 59 [54-63]). In adjusted models, more B-lines were associated with higher levels of C-reactive protein with an incidence rate ratio (IRR) of 16% (95%CI: 8%-24%) per log-unit increase (P<0.001) and higher Early Warning Score (IRR 5% [95%CI: 1%-0%] per point, P=0.02). Higher tricuspid regurgitation gradient was associated with more B-lines: IRR 2% (95%CI: 1%-3%) per mmHg, P<0.001) (Figure 1). Echocardiographic measures of left ventricular (LV) function (including LVEF and global longitudinal strain, left atrial volume, and LV filling pressures (E/e’)) and right ventricular function were not significantly associated with the number of B-lines. B-lines were not associated with N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations, even in patients with established HF. Lastly, B-lines were not associated with 30-day mortality. Conclusions Among hospitalized patients with COVID-19, B-lines on LUS are associated with markers of infectious disease severity and pulmonary hypertension but not with markers of left-sided HF.Figure1.Predictors of B-lines