Predictive factors for responders to tolvaptan in fluid management after cardiovascular surgery

OBJECTIVE To identify the predictive factors for responders to tolvaptan, a novel vasopressin type 2 receptor antagonist for fluid management after cardiovascular surgery. METHODS Between January 2013 and May 2014, 113 patients were treated with tolvaptan for fluid management after cardiovascular surgery. As indicators for the effects of tolvaptan, change in bodyweight during the tolvaptan administration period and correlations with perioperative factors were assessed. Thirty-one patients were administered tolvaptan at the first day after surgery (early tolvaptan group). In this group, urine volume during the 6 h before the initial tolvaptan administration was compared with that at 6 h after administration. RESULTS For all the patients, the change in bodyweight during the tolvaptan administration period significantly correlated with pre-operative serum creatinine (r = 0.19, p = 0.04) and albumin levels before tolvaptan administration (r = -0.29, p = 0.002). In the early tolvaptan group, the ratio of urine volume at 6 h before and 6 h after the initial tolvaptan administration significantly correlated with the pre-operative serum creatinine level (r = 0.43, p = 0.02), the serum albumin level before tolvaptan administration (r = -0.50, p = 0.004), and change in bodyweight (r = 0.38, p = 0.03). CONCLUSIONS In patients undergoing cardiovascular surgery, deteriorating renal function, increased bodyweight, and hypoalbuminemia were found to be predictive factors for responders to tolvaptan for postoperative fluid management.