Pulmonary congestion on lung ultrasound in ambulatory patients with heart failure and preserved ejection fraction.

Background: Early detection of pulmonary congestion among ambulatory patients with heart failure with preserved ejection fraction (HFpEF) is critical to optimize decongestive therapy prior to overt decompensation, yet traditional tools are insensitive.

Objectives: To examine the prevalence of B-lines, an ultrasound measure of pulmonary congestion, and their clinical and imaging correlates in patients with HFpEF.

Methods: In a prospective, multi-site observational study, using a pocket ultrasound device, 8-zone lung ultrasound was performed in outpatients with HFpEF, left ventricular ejection fraction (LVEF) ≥45% and NYHA class II-IV. B-lines and cardiac structure and function from echocardiograms were quantified off-line in core laboratories, blinded to clinical findings.

Results: Among 415 participants (mean age 74 years, 52% women, 51% obese, median N-terminal pro-B-type natriuretic peptide (NT-proBNP) 744 pg/ml) B-lines were detectable in 78% of patients ranging from 0 to 36 (median 3 [interquartile range 1, 6]). There was a linear association between B-line count and log-transformed NT-proBNP (P<0.001). Among patients in the highest tertile of B-lines, 76% had no crackles on auscultation, and 50% did not have elevated NT-proBNP levels. A higher B-line count was associated with larger sizes of cardiac chambers, greater left ventricular mass, higher filling pressures (E/e'), tricuspid regurgitant velocity, and inferior vena cava size, and worse right ventricular systolic function (P trend < 0.05 for all), but not LVEF.

Conclusions: Among ambulatory patients with HFpEF, lung ultrasound-detected B-lines were common, associated with NT-proBNP levels and clinically important echocardiographic features, and identified pulmonary congestion that was not always evident by auscultation.