Relevance of B-Lines on Lung Ultrasound in Volume Overload and Pulmonary Congestion: Clinical Correlations and Outcomes in Patients on Hemodialysis

Abstract

Background: Volume overload in patients on hemodialysis (HD) is an independent risk factor for cardiovascular mortality. B-lines detected on lung ultrasound (BLUS) assess extravascular lung water. This raises interest in its utility for assessing volume status and cardiovascular outcomes. Methods: End-stage renal disease patients on HD at the Island Rehab Center being older than 18 years were screened. Patients achieving their dry weight (DW) had a lung ultrasound in a supine position. Scores were classified as mild (0-14), moderate (15-30), and severe (>30) for pulmonary congestion. Patients with more than 60 were further classified as very severe. Patients were followed for cardiac events and death. Results: 81 patients were recruited. 58 were males, with a mean age of 59.7 years. 44 had New York Heart Association (NYHA) class 1, 24 had class 2, and 13 had class 3. In univariate analysis, NYHA class was associated with B-line classes (<0.001) and diastolic dysfunction (0.002). In multivariate analysis, NYHA grade strongly correlated with B-line classification (0.01) but not with heart function (0.95). 71 subjects were followed for a mean duration of 1.19 years. 9 patients died and 20 had an incident cardiac event. A Kaplan-Meier survival analysis demonstrated an interval decrease in survival times in all-cause mortality and cardiac events with increased BLUS scores (p = 0.0049). Multivariate Cox regression analysis showed the independent predictive value of BLUS class for mortality and cardiac events with a heart rate of 2.98 and 7.98 in severe and very severe classes, respectively, compared to patients in the mild class (p = 0.025 and 0.013). Conclusion: At DW, BLUS is an independent risk factor for death and cardiovascular events in patients on HD.