Association between B-lines on lung ultrasound, invasive haemodynamics, and prognosis in acute heart failure patients

Aims: Increased left atrial pressure leads to pulmonary congestion. Although the B-lines in lung ultrasound (LUS) are useful in detecting pulmonary congestion, data regarding the association between B-lines and invasive haemodynamics are inconsistent. This study aimed to explore the correlation of the B-line count by LUS with pulmonary capillary wedge pressure (PCWP) stratified for preserved and reduced ejection fraction (EF) in acute heart failure patients.

Methods and results: We performed a prospective observational study on 116 hospitalized patients with acute heart failure (mean age, 75.2 ± 10.3 years), who underwent right heart catheterization before discharge. LUS was performed in eight zones within 4 h of right heart catheterization and compared with PCWP separately in each EF group. Cardiac events were recorded 1 year after discharge. PCWP revealed a clear pivot point at which the B-lines began to increase in the overall cohort and each EF. Specific thresholds of the increase in B-lines were identified at 19 and 25 mmHg for preserved and reduced EF, respectively. Residual congestion at discharge was defined as the presence of ≥6 B-lines. Patients with residual congestion had a higher risk for cardiac events than those without residual congestion (hazard ratio, 12.6; 95% confidence interval, 4.71-33.7; log-rank, P < 0.0001).

Conclusion: A clear pivot point was associated with increased B-lines count in PCWP at 19 and 25 mmHg for preserved and reduced EF, respectively. Moreover, the increased B-line count above the defined cut-off used to quantify residual congestion was associated with significantly worse outcomes.