Pulmonary Congestion and Anemia in Hemodialysis: The Potential Link to Inflammation

Pulmonary congestion (PC) is common in hemodialysis (HD) patients. We explored the association of anemia and pulmonary congestion in HD patients. A prospective pilot observational study included 18 patients on maintenance HD. Individual B-lines scores (BLS; 8-sites method) were obtained by lung ultrasound, before and after the first two consecutive HD sessions of the week (HD1-HD2), with different inter-dialytic intervals (68 vs. 44 h). Bioimpedance spectroscopy body composition (BIS) was performed before each HD session. Hemoglobin (Hb) levels, in addition to circulating markers of chronic inflammation (soluble urokinase Plasminogen Activator Receptor [suPAR], soluble Suppression of Tumorigenicity 2 [sST2]) were obtained. Mean (±SD) BLS values were quite elevated at all time points: Pre-HD1 (16 ± 5.53), post-HD1 (15.3 ± 6.63), pre-HD2 (16.3 ± 5.26) and post-HD2 (13.6 ± 5.83), respectively. No direct significant correlation was found between inflammation markers levels and BLS. However, mean levels (±SD, ng/mL) of suPAR pre-HD1 (7.88 ± 3.07) and pre-HD2 (7.78 ± 3.02) remained significantly above the normal range (<4 ng/mL), and sST2 levels reached 2-fold the upper normal value in most patients (27.4 ± 17.8). Pulmonary congestion reflected by BLS was negatively correlated to Hb levels pre-HD1 (R² = 0.439, p = 0.003), and pre-HD2 (R² = 0.301, p = 0.018). In addition, Hb levels were negatively correlated to global volume status estimated by BIS (R² = 0.351, p = 0.009). Hemoglobin levels were negatively correlated to pulmonary congestion and to the global volume status evaluated by BIS. Chronic inflammation markers were increased in HD patients, suggesting a complex volume- and non-volume-dependent pathophysiology of pulmonary congestion in HD patients.