C13 - Potential Predictors of Advanced Heart Failure Secondary to Myxomatous Mitral Valve Disease in Dogs

Abstract: Background: Predictive variables and survival time of advanced heart failure (AHF) secondary to myxomatous mitral valve disease (MMVD) in dogs remain unknown.




Hypothesis/Objectives: This retrospective case-control study investigated predictive variables of AHF in dogs with MMVD.




Animals: The study included 38 dogs diagnosed with AHF and 38 with stable congestive heart failure (CHF) secondary to MMVD. AHF group was determined as dogs with refractory CHF treated with a total daily dosage of 8 mg/kg furosemide or the equivalent dose of torsemide. Dogs were included in the stable group, if there were no changes in the maintenance dose of furosemide (lower than 8 mg/kg/day) and other cardiac medicines above 12 weeks.




Methods: Logistic regression modeling was used to compare and analyze clinical, radiographic, and echocardiographic variables between groups. Survival times were analyzed using the Kaplan-Meier method.




Results: Left atrium to aortic root ratio, normalized left ventricular dimension at the end-diastole and end-systole, isovolumic relaxation time (IVRT) and the ratio of early transmitral inflow velocity to IVRT were associated with AHF progression. The median survival times in the stable group were significantly longer than those in the AHF group. After the diagnosis of AHF, the median survival times of all-cause mortality and cardiogenic mortality were 194 days (range 0–1,088 days) and 354 days (range 0–1,063 days), respectively.




Conclusions and clinical importance: AHF was significantly associated with enlarged left atrium, left ventricle and elevated left atrial pressure in dogs with MMVD; these dogs exhibited a survival time of approximately six months.