Mitral Valve Repair Metrics

One of the most frequent questions asked when considering a surgery as risky as cardio-pulmonary bypass, is what are the chances my dog will survive the surgery and what is the long term prognosis post-surgery. The answer is always "it depends".  Each dog is different, and each circumstance is unique.  Below are some guidelines to help you determine the best course of action for your dog based on aggregate data.  For more specific recommendations regarding surgery for your dog, please contact JASMINE Veterinary Medical Center directly.  Additional mitral valve repair statistics may be found in an abstract published by Dr. Masami Uechi from October 2016.

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Global survival rates of dogs who have undergone Mitral Valve Repair with Dr. Masami Uechi:

• 99% in stage B2

• 95% in stage C (if no pulmonary hypertension (PHT) before surgery)

• 85% in stage C (if there is PHT before surgery)

• 75% in stage D

The younger the dog is, the higher the success rate.

80% of the dogs operated on do not need any treatment or additional medications for mitral valve disease after surgery.

Mitral valve repair is needed if one or more of these conditions are present:

• If the dog is 13 years old or less AND

• As soon as the dog is in stage C

• If there is chordae tendinae rupture and/or grade 3 prolapse (even in stage B2)

• If there is a grade 3 or 4 mitral regurgitation (even in stage B2)

• If pulmonary arterial pressure (PAP) is less than 50 mmHg (otherwise the dog must be put on sildenafil 1-2 months before surgery)

• If the 2D LA/AO ratio in SAX is > 1.6 (right parasternal) (The LA/AO - meaning Left Atrial to Aorta Ratio - uses the relatively fixed diameter of the aorta to assess the degree of left atrial volume loading)

• If the NT-ProBNP level is > 2100 mol/l (even in stage B2)

Mitral Valve Repair under Cardio-Pulmonary Bypass (CPB) is a very complicated procedure

Weak points triggering a poor recovery from CPB are:

• The age of the dog (older dogs are more prone to Systemic Inflammatory Response Syndrome and thrombosis after surgery because their endothelium is more damaged)

• The degree of PHT before surgery (because one of the side effects of CPB is PHT)

• The systolic/myocardial function (because there is myocardial ischemia during CPB and the recovery is directly related to the myocardial health before surgery)

• The severity of the ACVIM stage

The surgery might be contraindicated (or have a lower survival rate) if:

• The dog is more than 13 years old

• There is severe PAP not improved after sildenafil therapy

• There is myocardial dysfunction/ischemia (low cardiac output) before surgery

• There is any concomitant medical disease (a secondary illness), for example:

  • A neoplastic process (a mass or tumor)

  • everely impaired renal function such as nephrotic syndrome or protein-losing enteropathy (kidney disorders)

  • Severe hepatic insufficiency (liver failure)

  • Unresolved infections

  • ndocrine disease (such as Cushings)

    • Hypothyroidism can be adjusted and treated 2-3 months before surgery
      

• There is coagulation dysfunction (an issue with blood clotting) and especially decreased levels of antithrombin 3 before surgery

  • Surgery might be difficult if there is a significant aortic insufficiency, an observation that must be recorded in the cardiology report