6. Myxomatous mitral valve diseases Flashcards
what is Myxomatous Mitral Valve Disease
characterised by progressive degeneration of the mitral valve which can lead to mitral regurgitation & subsequent left atrial & ventricular dilation
other names for Myxomatous Mitral Valve Disease
Acquired mitral regurgitation
Mitral valve insufficiency
Atrioventricular valvular degeneration
Endocardiosis
Chronic Mitral Valve Disease
Mitral Valve degeneration
Degenerative valvular disease
Cause of Myxomatous Mitral Valve Disease
unknown
predisposition of Myxomatous Mitral Valve Disease
Increase with age
small breeds
male > female
Pathophysiology of Myxomatous Mitral Valve Disease
valvular interstitial cells behave like activated myofibroblasts
Proteolytic enzymes degrade valvular collagen and elastin
2 pathways responsible for Myxomatous Mitral Valve Disease
Serotonin
TGF - Beta
what does regurgitation cause
increased cardiac workload and volume overload
consequences of Myxomatous Mitral Valve Disease
Mitral valve prolapse
Mitral insufficiency
Pulmonary oedema
LA & LV diilation - eccentric ventricular hypertrophy
Increased LA, pulmonary vein pressure
Pulmonary hypertension
Diagnosis of Myxomatous Mitral Valve Disease
systolic murmur
left sided HF
+/- right sided HF
lung oedema, chamber enlargement - xray
echo
normal LA: Aorta ratio
1:1
LA: Aorta ratio in case of HF
> 2/7:1
Stage A MMVD
All patients at risk for developing heart disease
no current apparent structural abnormality
No murmur
No treatment
Stage B1 MMVD
Asymptomatic patients with no evidence of cardiac remodelling
Stage B2 MMVD
Asymptomatic patients with evidence of cardiac remodelling
Stage C MMVD
Dogs with MMVD and clinical signs of HF
responsive to standard HF therapy
