['Long-term impact of levosimendan on renal function remains undefined. Prospectively, we evaluated effects of levosimendan on renal function in patients with advanced chronic heart failure awaiting cardiac transplantation.', 'Of 40 patients, 20 were randomized to receive levosimendan (10-minute bolus 12 microg/kg, followed by 0.1 microg/kg/min for 24 hours; LS Group), and 20 received no levosimendan (Controls). The groups did not differ in age, heart failure etiology, left ventricular ejection fraction, and plasma brain natriuretic peptide. Patients were followed for 3 months. At baseline, the groups did not differ in serum creatinine (1.92 +/- 0.13 mg/dL in LS Group versus 1.91 +/- 0.12 mg/dL in Controls, P = .81) and creatinine clearance (43.7 +/- 2.9 mL/min versus 43.9 +/- 2.8 mL/min, P = .84). At 3 months, we found a decrease in serum creatinine and an increase in creatinine clearance in LS Group, but not in Controls, leading to a significant intergroup difference in serum creatinine (1.60 +/- 0.26 mg/dL in LS Group versus 1.90 +/- 0.14 mg/dL in Controls, P = .005) and creatinine clearance (53.6 +/- 8.6 mL/min versus 44.0 +/- 3.3 mL/min, P = .005). An improvement in creatinine > or = 0.5 mg/dL occurred in 50% patients from LS Group compared with 10% of Controls (P = .005).'] Does levosimendan improve renal function in patients with advanced chronic heart failure awaiting cardiac transplantation?