Background:Oral administration of tolvaptan, a vasopressin V₂receptor antagonist, significantly reduces deterioration of renal function, which has recently been highlighted as an exacerbating factor for adverse events in patients with acute heart failure. In the present study we tested the hypothesis that concomitant administration of tolvaptan with a conventional diuretic is beneficial for perioperative body fluid management in patients who have undergone cardiac surgery.

Methods and Results:In all, 280 patients who underwent cardiac surgery were prospectively randomized to concomitant treatment with tolvaptan and a conventional diuretic (tolvaptan group; 147 patients) or treatment with a conventional diuretic alone (control group; 133 patients). Groups were compared in terms of the time required to restore preoperative body weight and the incidence of worsening renal function (WRF), defined as an increase in the serum creatinine level ≥0.3 mg/dL. The time required to restore preoperative body weight was significantly shorter in the tolvaptan than control group (mean [±SD] 3.97±1.95 vs. 5.02±2.83 days, respectively; P<0.001). The incidence of WRF was significantly lower in the tolvaptan than control group (n=11 [7.5%] vs. n=25 [18.8%], respectively; P=0.011).

Conclusions:Administration of tolvaptan with conventional diuretics in the early postoperative period after cardiac surgery could be beneficial in maintaining urine output without affecting renal function and may thus help avoid WRF.