Clinical findings and survival time in dogs with myxomatous mitral valve disease at the American College of Veterinary Internal Medicine stage D

Introduction/objectives: Data on dogs with end-stage myxomatous mitral valve disease (MMVD) are sparse. This study aimed to describe the clinical findings and survival time of dogs with MMVD at the American College of Veterinary Internal Medicine (ACVIM) stage D. Animals, materials, and methods: Dogs with MMVD receiving a total daily dosage of furosemide >8 mg/kg/day, or the equivalent dosage of torasemide, were retrospectively searched. Signalment, clinical, echocardiographic, electrocardiographic, laboratory, therapeutic, and outcome data were retrieved. A statistical analysis was performed to assess the entire population and compare specific subgroups of dogs based on their treatment protocols. Results: Sixty-one dogs were included. At the time of study inclusion, left-sided congestive heart failure, pulmonary hypertension, and arrhythmias were documented in 38 of 49 (77.5%), 23 of 61 (37.7%), and 18 of 61 (29.5%) dogs, respectively. The median time needed to progress from the ACVIM stage C to D was 245 days (144-376 days). After diagnosis of stage D, the median survival time for cardiac-related death was 155 days (103-259 days). When comparing dogs receiving furosemide or torasemide, there were no significant differences in median survival time (P=0.47), serum sodium concentration (P=0.554), or serum chloride concentration (P=0.638). However, dogs receiving torasemide had higher serum creatinine (P=0.025) and lower potassium concentrations (P=0.005). Study limitations: The limitations of this study included the retrospective study design and heterogeneous treatment protocols. Conclusions: This study provides novel data on the clinical characteristics and survival expectations of dogs with MMVD at the ACVIM stage D.