ACVIM consensus MMVD dogs 2019

Question 1

What percentage of dogs with heart dz have MMVD?

Answer 1

75%

Question 2

T/F In pt with MMVD the tricuspid valve can also be involved.

Answer 2

T, in 30% of the cases

Question 3

T/F female dogs are more likely to be affected by MMVD

Answer 3

F: male, 1.5x more

Question 4

T/F smaller breeds are predisposed and experience faster dz progression compared to large breeds.

Answer 4

F. larger dogs experience faster dz progression

Question 5

What breeds are predisposed?

Answer 5

CKCS, Dachshinds, mini and toy poodles

Question 6

what is the pathophys of MMVD?

Answer 6

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)

Question 7

Define heart failure.

Answer 7

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”).

Question 8

What are the stages of MMVD?

Answer 8

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

Question 9

T/F recommendations for stage A include no drugs but dietary adjustement.

Answer 9

F: no diet change needed.

Question 10

What is the only recommendation for stage A?

Answer 10

exclude from breeding dogs with a murmur or echo evidences of MR.

Question 11

What do you recommend for a B1?

Answer 11

repeat echo (or rads) in 6-12 months

Question 12

What are the criteria to define B2?

Answer 12

• murmur intensity >=3/6
• La:AO >= 1.6
  . LVIDDN (left ventr internal diameter in diastole normalized for BW) >= 1.7
• VHS>10.5

Question 13

And what of these criteria is most reliable?

Answer 13

echo evidences of La or LV enlargement

Question 14

What is VLAS?

Answer 14

vertebral left atrial size

Question 15

How do you obtain the VLAS?

Answer 15

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

Question 16

What VLAS value is likely to identify stage B2?

Answer 16

> =3

Question 17

What are the recommendation for stage B2?

Answer 17

• pimo
• mild dietary restriction
• ACEi (either at beginning or if LA size progressing fast)

Question 18

T/F: a pretreatment finding of a low-velocity E-wave on pulsed-wave
Doppler strongly L-heart failure.

Answer 18

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.

Question 19

What are the recommendation for acute tx of stage C?

Answer 19

1. furosemide
2. free access to H2O
3. Pimo
4. O2
5. centesis
6. antianxiety meds
7. dobutamin if no response to pimo
8. nitrorpusside CRI if non-responsive pulm edema
9. ACEi
10. nitroglicerin paste
11. add spironolactone TGH
12. diltiazine/digoxine if needed
13. diet: ensure adequate prot and restrict Na. Consider Mg, K and omega3

Question 20

How do you define stage D?

Answer 20

If more than a total daily dosage of 8 mg/kg of furosemide is required

Question 21

How does Torasemide work and when would you give it?

Answer 21

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.

Question 22

What is the MOA of hydralazine?

Answer 22

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.

Question 23

T/F: Afterload reduction in stage D dogs is most often associated with hypotension.

Answer 23

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.

Question 24

What is the MOA of sildenafil?

Answer 24

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.