Effects of Low-Dose Tolvaptan for Fluid Management After Cardiovascular Surgery

Abstract

Background: Perioperative management of body fluid levels after cardiovascular surgery with cardiopulmonary bypass is essential. Fluid management using tolvaptan with conventional diuretics is effective in maintaining urine output without worsening renal function. This study aimed to improve the in-out balance in the early perioperative phase using low-dose tolvaptan (3.75 mg/day). Methods and Results:This prospective, single-center, randomized, open-label study included 199 patients who underwent cardiovascular surgery with cardiopulmonary bypass in Kobe City Medical Center General Hospital between September 2018 and December 2020. Treatment with tolvaptan and loop diuretics (tolvaptan group; 99 patients) was compared with treatment with loop diuretics alone (control group; 100 patients) to evaluate achievement of preoperative body weight as the primary outcome. Secondary outcomes were urine volume, the incidence of worsening renal function (WRF), and postoperative paroxysmal atrial fibrillation (POAF). There was no significant difference between groups in the return to preoperative body weight on postoperative Day 6. The tolvaptan group had significantly increased urine volume (2,530 vs. 2,150 mL/day) and decreased total furosemide dose (24 vs. 32 mg) compared with the control group. No significant differences were observed in the development of WRF and POAF between the 2 groups. Conclusions:Although low-dose tolvaptan administration did not shorten the time to achieving preoperative body weight, it did significantly increase urine volume without WRF and POAF.

Optimal Patient Selection and Treatment Timing for Tolvaptan Therapy Following Cardiovascular Surgery

“…To the Editor: Matsuda et al demonstrated that post-surgical low-dose tolvaptan therapy did not shorten the time to achieving preoperative body weight compared with conventional diuretic therapy. 1 Optimal patient selection is key to successful tolvaptan therapy. In general, tolvaptan is indicated for patients refractory to conventional diuretics.…”

“…In the study of Matsuda et al, most patients had preserved renal function and the response to loop diuretics in the control group was acceptable. 1 Patients with left ventricular ejection fraction <40% and those with a glomerular filtration ratio <30 mL/min/1.73 m 2 were excluded from the study. These patients may be rather good candidates for tolvaptan therapy.…”

Optimal Patient Selection and Treatment Timing for Tolvaptan Therapy Following Cardiovascular Surgery ― Reply ―

“…We selected hemodynamically stable patients who did not undergo dialysis and were at low risk for safety, such as those who had a glomerular filtration rate ≥30 mL/min/1.73 m 2 and left ventricular ejection fraction ≥40%. 5 The administration of tolvaptan was initiated on postoperative Day (POD) 2; this was because patients are hemodynamically unstable after cardiovascular surgery. However, the earlier initiation of tolvaptan may be clinically beneficial in fluid management, because the low-risk group was hemodynamically stable.…”