Lung Ultrasound in Acute Heart Failure: Prevalence of Pulmonary Congestion and Short- and Long-Term Outcomes

Abstract

Objectives: This study sought to assess the prevalence, changes in, and prognostic importance of B-lines, a pulmonary congestion measure by using a simplified lung ultrasonography (LUS) method in acute heart failure (AHF).

Background: Pulmonary congestion is an important finding in AHF, but conventional methods for its detection are insensitive.

Methods: In a 2-site, prospective, observational study, 4-zone LUS was performed early during hospitalization for AHF (LUS1) and at discharge (LUS2). B-lines were quantified off-line, blinded to clinical findings and outcomes, by a core laboratory.

Results: Among 349 patients (median, 75 years of age; 59% men; mean ejection fraction 39%), the sum of B-lines in 4 zones ranged from 0 to 18 (LUS1). The risk of an adverse in-hospital event increased with rising number of B-lines on LUS1: the odds ratio for each B-line tertile was 1.82 (95% confidence interval [CI]: 1.14 to 2.88; p = 0.011). B-line count decreased from a median of 6 (LUS1) to 4 (LUS2; p < 0.001) over 6 days (median). In 132 patients with LUS2 images, the risk of HF hospitalization or all-cause death was greater in patients with a higher number of B-lines at discharge. This relationship was stronger closer to discharge: unadjusted hazard ratio (HR) at 60 days was 3.30 (95% CI: 1.52 to 7.17; p = 0.002); 2.94 at 90 days (95% CI: 1.46 to 5.93; p = 0.003); and 2.01 at 180 days (95% CI: 1.11 to 3.64; p = 0.021). The association between number of B-lines and short- and long-term outcomes persisted after adjusting for important clinical variables, including N-terminal pro-B-type natriuretic peptide.

Conclusions: Pulmonary congestion using a simplified 4-zone LUS method was common in patients with AHF and improved with therapy. A higher number of B-lines at baseline and discharge identified patients at increased risk for adverse events.

Keywords: acute heart failure; lung ultrasonography; prognosis; pulmonary congestion.

Figure 1.. Overview of 8 and 4-zone lung ultrasound technique

“A) 8-zone and B) 4-zone lung ultrasound method. Adapted from: Platz E et al. Eur J Heart Fail. 2017;19(9):1154-1163.

Figure 2.. Dynamic changes in B-lines (n=129)

4-zone LUS early during hospitalization and at discharge.

Central Illustration:. Cumulative incidence of HF hospitalization or death by pre-discharge B-line tertiles (n=132)

Cumulative incidence plot of composite long-term outcome.