Keynote Message

Current common medical treatment for chronic mitral valve disease due to myxomatous mitral valve degeneration (MMVD) includes diuretics, pimobendan, ACE-I, and spironolactone. However, although current guidelines for the diagnosis and treatment of MMVD in dogs provide some recommendations about medical therapy at different stages of the disease, decision on when to start the treatment, and which drugs should be used, remains mainly a choice of the clinician. A recent study suggests that pimobendan is able to delay onset of congestive heart failure in dogs with MMVD and advanced cardiac remodelling. The Longitudinal Outcome Of Canine Mitral valve disease (LOOK-mitral) study is a multicenter prospective longitudinal study intended to:

1.  Assess the natural history of canine MMVD in a large referred population

2.  Assess the prevalence and effects of co-morbidities on the natural history of the disease

3.  Identify risk factors for disease progression and death

The study was initiated in October 2015 and represents a collaborative research project between the Virginia-Maryland College of Veterinary Medicine and the CVCA Cardiac Care for Pets group in USA. Inclusion criteria for study enrollment is a diagnosis of MMVD confirmed by echocardiographic exam. Dogs are enrolled in the study at the time the diagnosis is confirmed by a cardiology specialist. Collected data include physical exam, radiographic findings, ECG findings, echocardiography, co-morbidities, laboratory results, and treatment. Data are collected at each reevaluation until the termination of the study (October 2020) or until the death of the dog. To date, the database contains clinical information from 2,156 dogs of 104 different breeds. Follow-up examination data are available for approximately 30% of the dogs. In this session, current recommendation for medical treatment of dogs affected by MMVD will be critically appraised. Moreover, preliminary data about treatment of dogs enrolled in the LOOK-Mitral study will be presented.

Key References

1.  Boswood A, Haggstrom J, Gordon SG, et al. Effects of pimobendan in dogs with preclinical myxomatous mitral valve disease and cardiomegaly: The EPIC study - A randomized clinical trial. J Vet Intern Med. 2016;30(6):1765–1779.

2.  Borgarelli M, Crosara S, Lamb K, et al. Survival characteristics and prognostic variables of dogs with preclinical chronic degenerative mitral valve disease attributable to myxomatous degeneration. J Vet Intern Med. 2012;26(1):69–75.

3.  Borgarelli M, Haggstrom J. Canine degenerative mitral valve disease: natural history, clinical presentation and therapy. Vet Clin North Am Small Anim Pract. 2010;40(4):651–663.

4.  Atkins C, Bonagura J, Ettinger S, et al. Guidelines for the diagnosis and treatment of canine chronic valvular heart disease. J Vet Intern Med. 2009;23:1142–1150.