Prognostic impact of lung ultrasound detected B-lines on hospitalised ischaemic heart failure with mildly reduced ejection fraction patients

Objectives: Prognostic impact of lung ultrasound-derived B-lines (LUS-BL) in heart failure with mildly reduced left ventricular ejection fraction (HFmrEF) patients remains elusive. We evaluated the correlation between LUS-BL and prognosis in HFmrEF patients.

Methods: This is a subgroup analysis based on our previously published retrospective study with 1691 HFmrEF patients. This subgroup analysis involved 574 patients with LUS-BL results at admission. After discharge, patients underwent clinical follow-up for a minimum of 1 year through telephone, clinical visits or community visits. The primary endpoint was defined as cardiovascular (CV) event, including CV-related mortality or HF hospitalisation at 90 days and 1 year after discharge.

Results: CV event at 90 days was significantly increased with higher LUS-BL number (0, 1-2, 3-9 and ≥10: 20%, 14%, 18% and 33%, p=0.008), while CV event rate at 1 year was similar among groups (45% vs 45% vs 42% vs 50%, p=0.573). Older age, hypertension (HR=2.06, 95% CI 1.31 to 3.25), higher right ventricular diameter (>23 mm, HR=2.008, 95% CI 1.37 to 2.94), increased ratio of early transmitral flow velocity to early mitral annular velocity (>24, HR=1.79, 95% CI 1.11 to 2.26) and higher LUS-BL number (>11, HR=1.510, 95% CI 1.01 to 2.26) were identified as independent determinants associated with increased risk of CV event at 90 days after discharge. The Harrell's C-Statistic analysis, based on the Cox regression models, demonstrated a significant improvement in the predictive ability of the model that incorporated both clinical and echocardiographic risk factors along with LUS-BL (areas under the curve (AUC)=0.72) compared with the model comprising only clinical risk factors and LUS-BL (AUC=0.69, p=0.036), or to the model with echocardiographic risk factors and LUS-BL (AUC=0.68, p=0.025).

Conclusion: In HFmrEF patients with ischaemic heart disease, admission LUS-BL>11 is independently associated with an increased risk of CV event at 90 days following discharge.