Intraoperative Infusion Volume and Incidence of Postoperative Congestive Heart Failure in Dogs with Myxomatous Mitral Valve Disease

In this retrospective study, we investigated the fluid management during surgical anesthesia and occurrence of congestive heart failure (pulmonary edema) in MMVD-affected dogs undergoing noncardiac surgery. Dogs with MMVD were classified into stage B1 (B1 group: n=109), stage B2 and C (B2・C group: n=22) according to the American College of Veterinary Internal Medicine (ACVIM) consensus guideline, and dogs without MMVD (n=132) were used as a control group. As a result, no postoperative pulmonary edema occurred. There were no significant differences between the B1 group and the control group in total infusion volume during anesthesia (ml/kg) or in the percentage of dogs administered diuretics (mean ± SD: 21.5 ± 9.9 vs. 23.5 ± 10.2, 2/109 vs. 0/132). On the other hand, the B2・C group had significantly lower total infusion volume during anesthesia (ml/kg) than the control group (mean ± SD: 14.2 ± 13.3 vs. 23.5 ± 10.2), but a significantly higher percentage of dogs administered diuretics due to suspected volume overload (5/22 vs. 0/132). The results of this study suggest that dogs in stage B1 have a low risk of developing postoperative congestive heart failure, even with the same fluid management as dogs without MMVD. In stage B2 and C dogs, limitation of infusion and postoperative monitoring and diuresis may have contributed to the prevention of congestive heart failure.