ACVIM consensus MMVD dogs 2019 Flashcards
What percentage of dogs with heart dz have MMVD?
75%
T/F In pt with MMVD the tricuspid valve can also be involved.
T, in 30% of the cases
T/F female dogs are more likely to be affected by MMVD
F: male, 1.5x more
T/F smaller breeds are predisposed and experience faster dz progression compared to large breeds.
F. larger dogs experience faster dz progression
What breeds are predisposed?
CKCS, Dachshinds, mini and toy poodles
what is the pathophys of MMVD?
Changes in the cellular constituents as well as the intercell matrix of the valve apparatus.
Changes involve both the collagen
content and the alignment of collagen fibrils within the valve. Expansion
of the spongiosa layer is characterized by changes in the proteoglycan
content of this layer. Dysregulation of the extracell matrix appears to
be central to these changes.
- increase proteolytic enzymes, including matrix metalloproteinases, which
degrade collagen and elastin
- Progressive valvular regurgitation increases cardiac work, leading to
ventricular remodeling (eccentric hypertrophy of both the atrium
and ventricle, and intercellular matrix changes)
Define heart failure.
Heart disease that affects heart function such that either venous pressures increase so severely that fluid accumulates in the lungs or a body cavity (congestive heart failure [CHF], “backward heart failure”), or
the heart’s pumping ability is compromised such that it cannot meet the
body’s needs, in the face of either normal
or increased venous pressures (“forward heart failure”).
What are the stages of MMVD?
A: high risk
B1: asymptomatic, structural heart dz but no remodelling
B2: asymptomatic, structural heart dz with rads and echo findings of LA and LV enlargement
C: current or past failure caused by MMVD
D: refractory to standard tx
T/F recommendations for stage A include no drugs but dietary adjustement.
F: no diet change needed.
What is the only recommendation for stage A?
exclude from breeding dogs with a murmur or echo evidences of MR.
What do you recommend for a B1?
repeat echo (or rads) in 6-12 months
What are the criteria to define B2?
- murmur intensity >=3/6
- La:AO >= 1.6
. LVIDDN (left ventr internal diameter in diastole normalized for BW) >= 1.7 - VHS>10.5
And what of these criteria is most reliable?
echo evidences of La or LV enlargement
What is VLAS?
vertebral left atrial size
How do you obtain the VLAS?
by drawing a line from the center of the most ventral aspect of the carina to the
most caudal aspect of the LA where it intersects with the dorsal border of the caudal vena cava, that line then is transposed to the cranial edge of the 4th thoracic vertebral body
What VLAS value is likely to identify stage B2?
> =3
What are the recommendation for stage B2?
- pimo
- mild dietary restriction
- ACEi (either at beginning or if LA size progressing fast)
T/F: a pretreatment finding of a low-velocity E-wave on pulsed-wave
Doppler strongly L-heart failure.
F: most dogs in Stages C and D have high-velocity
early filling waves.
E wave= Early diastolic flow through the mitral valve, driven by the pressure gradient between the full LA and the relaxing LV. In most canine and feline patients, the commonest cause of accelerated transmitral flow is pathologically-increased LA pressure, due to either mitral insufficiency or compromised LV filling.
What are the recommendation for acute tx of stage C?
- furosemide
- free access to H2O
- Pimo
- O2
- centesis
- antianxiety meds
- dobutamin if no response to pimo
- nitrorpusside CRI if non-responsive pulm edema
- ACEi
- nitroglicerin paste
- add spironolactone TGH
- diltiazine/digoxine if needed
- diet: ensure adequate prot and restrict Na. Consider Mg, K and omega3
How do you define stage D?
If more than a total daily dosage of 8 mg/kg of furosemide is required
How does Torasemide work and when would you give it?
potent long-acting loop diuretic may be used to treat dogs no longer adequately responsive to furosemide (5%-10% of the current furosemide
dosage to deliver a furosemide-equivalent dose). It produces less RAAS activation than furosemide.
What is the MOA of hydralazine?
Direct systemic arteriolar vasodilator→ alters smooth muscle IC Ca2+ metabolism (interferes with Ca2+ movements + prevents initiation+ maintenance of contractile state).
It is a semicarbazide-sensitive amine oxidase (SSAO) inhibitor.
Effect on arterioles > veins.
T/F: Afterload reduction in stage D dogs is most often associated with hypotension.
because afterload reduction may increase CO substantially in the setting of severe MR and heart failure, administration of an effective arterial dilator drug in this setting does not necessarily compromise blood pressure.
What is the MOA of sildenafil?
Sildenafil inhibits phosphodiesterase type 5, an enzyme that metabolizes cyclic guanosine monophosphate, thereby enhancing the cyclic guanosine monophosphate–mediated relaxation and growth inhibition of vascular smooth-muscle cells, including those in the lung.
