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Background: Adequate fluid management is an important component of patient care following cardiac surgery. Our aim in this study was to determine the benefits of tolvaptan, an oral selective vasopressin-2 receptor antagonist that causes electrolyte-free water diuresis, in postoperative fluid management. We prospectively examined the effect of tolvaptan on renal excretion of electrolytes and urea nitrogen in cardiac surgery patients., Methods: Patients undergoing coronary artery bypass surgery were randomized to receive conventional loop diuretics (Group C, n = 30) or conventional loop diuretic therapy plus tolvaptan (Group T, n = 27). Fractional excretions of sodium (FENA), potassium (FEK) and urea nitrogen (FEUN) were measured in both groups during post-surgical hospitalization., Results: Urine output was greater with tolvaptan (Group T) than without it (Group C), and some patients in Group C required intravenous as well as oral loop diuretics. Serum sodium concentrations decreased after surgery in Group C, but were unchanged in Group T (postoperative day [POD] 3, 139.8 ± 3.5 vs. 142.3 ± 2.6 mEq/L, p = 0.006). However, postoperative FENA values in Group C did not decrease, and the values were similar in both groups. Serum potassium levels remained lower and FEK values remained higher than the preoperative values, but only in Group C (all p < 0.05). BUN increased postoperatively in both groups, but it remained higher than its preoperative value only in Group C (all p < 0.01). Group T showed an initial increase in BUN, which peaked and then returned to its preoperative value within a week. The FEUN increased postoperatively in both groups, but the change was more pronounced in Group T (POD7, 52.7 ± 9.3 vs. 58.2 ± 6.5 %, p = 0.025)., Conclusions: Renal excretion of sodium and potassium reflects the changes in serum concentration in patients treated with tolvaptan. Patients treated only with loop diuretics showed a continuous excretion of sodium and potassium that led to electrolyte imbalance, whereas the combination of loop diuretics and tolvaptan increased renal urea nitrogen elimination. Tolvaptan therefore appears to be an effective diuretic that minimally affects serum electrolytes while adequately promoting the elimination of urea nitrogen from the kidneys in patients undergoing coronary artery bypass surgery., Trial Registration: The present study is registered with the UMIN Clinical Trials Registry (ID: UMIN000011039 ).

Background: Galectin-3 is a marker of myocardial inflammation and fibrosis shown to correlate with morbidity and mortality in heart failure (HF). We examined the utility of galectin-3 as a marker of the severity of HF, the response of galectin-3 levels to ventricular assist device (LVAD) implantation or heart transplantation (HTx), and its use as a prognostic indicator., Methods: Plasma galectin-3 was measured using a commercially available ELISA assay in patients with stable HF (n = 55), severe HF (n = 63), at 3 (n = 17) and 6 (n = 14) months post-LVAD and at LVAD explantation (n = 23), patients following HTx (n = 85) and healthy controls (n = 30)., Results: Galectin-3 levels increase with the severity of HF (severe HF: 28.2 ± 14, stable HF: 19.7 ± 13, p = 0.001; controls: 13.2 ± 9 ng/ml, p = 0.02 versus stable HF). Following LVAD implantation, galectin-3 levels are initially lower (3 months: 23.7 ± 9, 6 months: 21.7 ± 9 versus 29.2 ± 14 ng/ml implantation; p = NS) but are higher at explantation (40.4 ± 19 ng/ml; p = 0.005 versus pre-LVAD). Galectin-3 levels >30 ng/ml are associated with lower survival post-LVAD placement (76.5 % versus 95.0 % at 2 years, p = 0.009). After HTx, galectin-3 levels are lower (17.8 ± 7.1 ng/ml post-HTx versus 28.2 ± 14 pre-HTx; p < 0.0001). Patients with coronary allograft vasculopathy (CAV) post-HTx showed higher galectin-3 levels (20.5 ± 8.8 ng/ml versus 16.8 ± 6.3, p = 0.1) and the degree of CAV correlated with levels of galectin-3 (r (2) = 0.17, p < 0.0001)., Conclusions: Galectin-3 is associated with the severity of HF, exhibits dynamic changes during mechanical unloading and predicts survival post-LVAD. Further, galectin-3 is associated with the development on CAV post-HTx. Galectin-3 might serve as a novel biomarker in patients with HF, during LVAD support and following HTx.