Detection and prognostic value of pulmonary congestion by lung ultrasound in ambulatory heart failure patients

Pulmonary congestion is a common and important finding in heart failure (HF). While clinical examination and chest radiography are insensitive, lung ultrasound (LUS) is a novel technique that may detect and quantify subclinical pulmonary congestion. We sought to independently relate LUS and clinical findings to 6-month HF hospitalizations and all-cause mortality (composite primary outcome). We used LUS to examine 195 NYHA class II-IV HF patients (median age 66, 61% men, 74% white, ejection fraction 34%) during routine cardiology outpatient visits. Lung ultrasound was performed in eight chest zones with a pocket ultrasound device (median exam duration 2 min) and analysed offline. In 185 patients with adequate LUS images in all zones, the sum of B-lines (vertical lines on LUS) ranged from 0 to 13. B-lines, analysed by tertiles, were associated with clinical and laboratory markers of congestion. Thirty-two per cent of patients demonstrated ≥3 B-lines on LUS, yet 81% of these patients had no findings on auscultation. During the follow-up period, 50 patients (27%) were hospitalized for HF or died. Patients in the third tertile (≥3 B-lines) had a four-fold higher risk of the primary outcome (adjusted HR 4.08, 95% confidence interval, CI 1.95, 8.54; P < 0.001) compared with those in the first tertile and spent a significantly lower number of days alive and out of the hospital (125 days vs. 165 days; adjusted P < 0.001). Pulmonary congestion assessed by ultrasound is prevalent in ambulatory patients with chronic HF, is associated with other features of clinical congestion, and identifies those who have worse prognosis.