Mitral Valve Disease in Dogs – What Do the Experts Say? The ACVIM Consensus Report on Mitral Valve Disease in the Dog

Introduction

Other than heartworm disease, most important cardiovascular syndrome in veterinary medicine is canine chronic mitral valvular disease (canine chronic valvular heart disease – CCVHD, endocardiosis, myxomatous valve degeneration, mitral regurgitation [MR]), affecting 85% of dogs aged 13 years or older and constituting 75% of canine heart disease. 1 The American College of Veterinary Internal Medicine’s Board of Regents selected a group of European and U.S. ACVIM-boarded cardiologists to arrive at a consensus as to the diagnosis and treatment of CCVHD. 1 Appropriately, the 10 panel members represented diverse points of view on cardiac therapeutics. Evidence was derived from sources ranging from placebo-controlled, double-blind clinical trials and other experimental data to anecdote, clinical experience, and expert opinion, with greater weight put on the former. To achieve consensus, all 10 panelists had to agree on the recommendation. In addition to putting forth consensus recommendations on diagnostic and therapeutic options, the panel revealed instances when the majority of panelists agreed upon a recommendation, even if consensus was not reached. The group chose to use a new grading system for cardiac disease severity and progression, which is described below. In addition to the panels’ recommendations, I will render my own personal opinion, when I feel that it is appropriate to do so. Space constraints preclude discussion of the panel’s recommendations on diagnostic steps for each category of CCVHD and treatment recommendations for refractory heart failure (Stage D). Hence I will cover only management recommendations for dogs at risk for CCVHD, those with very early disease, those with cardiac enlargement, those hospitalized for heart failure, and those treated for heart failure at home.

Mitral Valve Disease Severity Classification

The panel chose to adapt a novel classification scheme modeled after that put forth by the American Heart Association and the American College of Cardiology. This scheme avoids the NYHA classification pitfall of using progressive loss of exercise tolerance to grade disease severity. In addition, it adds an early category (A), during which dogs are without evidence of disease, but which are at risk for developing disease (e.g. Cavalier King Charles Spaniels). The ACVIM classification system is shown in Figure 1. Class A CCVHD patients are at risk, B1 have murmurs but no cardiomegaly, B2 have cardiomegaly, C a have acute heart failure, requiring hospitalization, C c have chronic heart failure and are treated at home, D a patients have refractory heart failure, requiring hospitalization, while D c have refractory heart failure but can be managed at home. The panel attempted to achieve consensus on the management of dogs in all categories of severity. Only the therapeutic recommendations for ACVIM Class A through C are discussed herein. […]