Echocardiographic predictors of survival in dogs with myxomatous mitral valve disease

Objectives: To evaluate vena contracta and other echocardiographic measures of myxomatous mitral valve disease (MMVD) severity in a multivariable analysis of survival in dogs. Animals: 70 dogs diagnosed with MMVD from stored echocardiographic images that met study inclusion criteria. Methods: Left heart dimensions were measured as well as mitral regurgitant jet area/left atrial area (JAR), early mitral filling velocity (E-vel), extent of mitral valve prolapse in right and left views (Prol(R), Prol(L)), Prol indexed to aortic diameter (Prol(R):Ao, Prol(L):Ao), presence of a flail leaflet (Flail(R), Flail(L)), and mitral regurgitation vena contracta diameter (VCR, VCL) indexed to aortic diameter (VCR:Ao, VCL:Ao). Follow-up from referring veterinarians was obtained by questionnaire or telephone to determine survival times. Inter- and intra-observer agreement was evaluated with Bland-Altman plots and weighted Kappa analysis. Survival was analyzed using Kaplan-Meier curves, logrank tests and Cox's proportional hazards. Results: Logrank analysis showed VCL:Ao, VCR:Ao, Flail(L), Prol(R):Ao, Prol(L):Ao, left ventricular internal dimension in diastole indexed to aortic diameter (LVIDD:Ao) > 2.87, left atrium to aorta ratio (LA/Ao) > 1.6, and E-vel > 1.4 m/s were predictors of cardiac mortality. In a multivariable analysis, the independent predictors of cardiac mortality were E-vel > 1.4 m/s [hazard ratio (HR) 5.0, 95% confidence interval (CI) 2.5-10.3], Flail(L) (HR 3.1, 95% CI 1.3-7.9), and Prol(R):Ao (HR 2.8, 95% CI 1.3-6.3). Conclusions: Echocardiographic measures of mitral regurgitation severity and mitral valve pathology provide valuable prognostic information independent of chamber enlargement in dogs with MMVD. (C) 2014 Elsevier B.V. All rights reserved.