Clinical findings and risk factors for clinical outcomes in dogs with myxomatous mitral valve disease hospitalized for cardiogenic pulmonary edema.

Background: Cardiogenic pulmonary edema (CPE) is a serious development for dogs with myxomatous mitral valve disease (MMVD). Due to the hemodynamic impact of MMVD, and changes in left atrial pressure and pulmonary capillary pressure, CPE commonly requires hospitalization. Hypothesis/Objectives: To characterize clinical findings particularly in respiratory rate and breathing effort in dogs with MMVD hospitalized with CPE and assess them as risk factors focusing on selected clinical outcomes. Animals: 100 dogs with MMVD hospitalized with CPE were included, with a median age of 12.0 years and a median body weight of 3.31 kg. Fifty-five dogs were male and 45 were female. Methods: Prospective cohort study measuring clinical parameters and Tufts Dyspnea Score (TDS) during hospitalization to assess outcomes. Descriptive statistics and regression analysis were used. Results: Upon hospital presentation, the median respiratory rate was 64 breaths per minute, the median TDS was 5 (ranging from 0 to 10). The median duration of oxygen administration was 20 h. Ninety-five of 100 dogs survived to hospital discharge. For the 93 dogs with follow-up information, 17 experienced cardiac death and 22 experienced re-hospitalization for CPE within 2 months post-discharge. Lower minimum TDS within 12 h was found to be associated with survival to hospital discharge. The administration of parenteral inotropes and higher minimum respiratory rate within 12 h were associated with cardiac death within 2 months post-discharge. Dogs with a louder murmur at presentation were more likely to experience re-hospitalization due to CPE within 2 months post-discharge. Conclusions and clinical importance: We observed a high survival rate to discharge in dogs with MMVD hospitalized with CPE; however, cardiac death and rehospitalization due to CPE within 2 months post-discharge were common in these dogs. No clinical parameter measured before initiating treatment was associated with in-hospital mortality. However, risk factors such as systolic blood pressure below 90 mmHg upon hospital presentation, administered parenteral inotropes and the minimum respiratory rate during the initial 12 h have been associated with an increased risk of cardiac death within 2 months post-discharge.