Abstract 4368240: Increased Number of B-Lines on Lung Ultrasound Is Associated with Elevated Filling Pressures and Adverse Outcomes in Acute Heart Failure

Background: B-lines on lung ultrasound (LUS) are useful for identifying pulmonary congestion in acute heart failure (AHF), but their relationship with detailed cardiac structure and function remains less studied. Hypothesis: We hypothesized that clinical and echocardiographic characteristics and risk of all-cause mortality and AHF readmission differ based on B-line burden. Methods: This prospective, two-center observational cohort study (2022-2024) enrolled adults hospitalized with clinical signs of AHF, irrespective of LVEF or heart failure history. Transthoracic echocardiography, 8-zone LUS and laboratory data were acquired shortly after admission (median time: 48 hours). B-line groups (0-2, 3-7, ≥8) were predefined from literature to reflect increasing pulmonary congestion. The primary endpoint investigated was a composite of all-cause mortality or AHF readmission, assessed at both 30 and 180 days after enrollment. Results: Among 470 patients (mean age 78.1 ± 11.5 years; 41.1% female; mean BMI 26.5 kg/m 2 ± 5.96), 155 (33.0%) had 0-2 B-lines, 120 (25.5%) had 3-7 B-lines and 195 (41.5%) had ≥8 B-lines. Increasing B-line burden was associated with a higher prevalence of known heart failure (p for trend=0.023), significant valvular disease (p for trend<0.001), higher NYHA-class (p for trend=0.018) and peripheral edema at admission (p for trend=0.014). On echocardiography, higher B-line burden was associated with increased filling pressures (E/é ≥14: 31.0% vs. 50.8% vs. 56.9%, p for trend<0.001) and left atrial enlargement (LAVI ≥34 mL/m 2 : 22.6% vs. 32.5% vs. 39.0%, p for trend=0.020). The composite endpoint occurred in 22.6% and 45.6% of patients with ≥8 B-lines at 30 and 180 days, compared to 9.7% and 24.5% in those with 0–2 B-lines (p for trend<0.001). In unadjusted Cox regression, patients with ≥8 B-lines had more than twice the risk of the composite endpoint at 30 days (HR 2.55, 95% CI 1.42-4.58) and 180 days (HR 2.20, 95% CI 1.51-3.22) compared to those with 0-2 B-lines. After adjustment for age, sex, BMI and comorbidities, the association remained significant at both 30 days (HR 2.05, 95% CI 1.05-4.00) and 180 days (HR 1.74, 95% CI 1.12-2.70). Conclusion: Among individuals hospitalized with AHF, greater B-line burden on LUS early during the admission was associated with elevated filling pressures and increased risk of all-cause mortality or AHF readmission, highlighting the potential prognostic value of B-lines on LUS.