Lung ultrasound b-lines as a non-invasive tool for estimating left ventricular filling pressure: correlation with invasive hemodynamics

Background Direct measurement of left ventricular end-diastolic pressure (LVEDP) remains the gold standard for evaluating hemodynamic congestion, yet its invasive nature limits its use in daily clinical practice. Lung ultrasound (LUS) quantifies extravascular lung water through B-lines and could represent a non-invasive, bedside alternative. However, its direct correlation with invasively measured LVEDP has not been validated. Purpose To determine the diagnostic performance of LUS-derived B-lines in estimating invasively measured LVEDP and to explore their relationship with echocardiographic and biomarker-based surrogates of left ventricular filling pressure. Methods In this prospective, single-centre study, consecutive adults undergoing left heart catheterization were assessed. Within 60 minutes post-procedure, a standardized 8-zone anterior LUS protocol was performed by trained operators blinded to hemodynamic data. The total B-line count was compared to invasively measured LVEDP. Correlations with echocardiographic parameters (E/e’, LVEF) and NT-proBNP were analyzed using Pearson’s coefficient and multivariate linear regression. Results Sixty-one patients were included (73% male, median age 59 years). Elevated LVEDP (≥18 mmHg) was present in 34%. Patients with elevated LVEDP exhibited a significantly higher B-line count (median 4 [0–18] vs. 0 [0–1], p = 0.002). B-lines strongly correlated with LVEDP (r = 0.64, p < 0.001), comparable to the correlation observed for E/e´ (r = 0.62, p < 0.001). LVEF inversely correlated with LVEDP (r = –0.53, p < 0.001), whereas NT-proBNP showed no significant relationship (r = 0.08, p = 0.88). In multivariate analysis, B-lines (β = 0.57, p = 0.001) and E/e´ (β = 0.78, p = 0.016) independently predicted elevated LVEDP. Conclusion B-line quantification by LUS provides a robust, non-invasive estimate of LVEDP, demonstrating strong agreement with direct intracavitary measurements. This translational approach bridges invasive hemodynamic monitoring and bedside assessment, enabling rapid, radiation-free evaluation of cardiac congestion. Incorporating LUS into clinical algorithms may enhance diagnostic precision and guide tailored therapy in acute and chronic heart failure.