What is the treatment approach for a dog with left-sided heart failure, ascites, mitral and tricuspid regurgitation?

From the Guidelines

The treatment approach for a dog with left-sided heart failure, ascites, and both mitral and tricuspid regurgitation should prioritize a comprehensive medication regimen and consider surgical intervention for tricuspid regurgitation, as indicated by recent guidelines 1. The cornerstone of therapy includes furosemide (1-4 mg/kg orally every 8-12 hours) to reduce fluid accumulation, pimobendan (0.25-0.3 mg/kg orally every 12 hours) to improve cardiac contractility, and an ACE inhibitor such as enalapril (0.5 mg/kg orally every 12-24 hours) to reduce afterload and mitigate the renin-angiotensin-aldosterone system activation. For the ascites specifically, spironolactone (1-2 mg/kg orally every 12-24 hours) should be added as an aldosterone antagonist to help manage fluid retention. The tricuspid regurgitation contributing to right-sided congestion may require additional diuresis, potentially with hydrochlorothiazide (2 mg/kg orally every 12-24 hours) in severe cases. Regular monitoring of renal values, electrolytes, and blood pressure is essential as these medications can cause azotemia, hypokalemia, and hypotension. Dietary sodium restriction is also important, and periodic abdominocentesis may be necessary for severe ascites that is unresponsive to medical management. Surgical intervention for tricuspid regurgitation should be considered in patients with severe TR, as indicated by guidelines 1, which suggest that surgery is indicated in symptomatic patients with severe TR, and should be considered in patients with moderate primary TR, as well as in patients with mild or moderate secondary TR and significant dilatation of the annulus (≥40 mm). Key points to consider in the treatment approach include:

• Comprehensive medication regimen targeting both sides of the heart
• Consideration of surgical intervention for tricuspid regurgitation
• Regular monitoring of renal values, electrolytes, and blood pressure
• Dietary sodium restriction and periodic abdominocentesis as needed.

From the FDA Drug Label

Indications: VETMEDIN (pimobendan) is indicated for the management of the signs of mild, moderate, or severe congestive heart failure in dogs due to clinical myxomatous mitral valve disease (MMVD) or dilated cardiomyopathy (DCM). VETMEDIN is indicated for use with concurrent therapy for congestive heart failure (e.g.,furosemide, etc.) as appropriate on a case-by-case basis. The treatment approach for a dog with left-sided heart failure, ascites, mitral and tricuspid regurgitation may include pimobendan in conjunction with other therapies, such as furosemide, as pimobendan is indicated for the management of congestive heart failure in dogs due to mitral valve disease, which is relevant to this case given the presence of mitral regurgitation 2.

• Key considerations include the use of pimobendan with concurrent therapy for congestive heart failure on a case-by-case basis.
• Treatment goals should focus on managing the signs of congestive heart failure.

From the Research

Treatment Approach

The treatment approach for a dog with left-sided heart failure, ascites, mitral and tricuspid regurgitation involves a combination of medications to manage the symptoms and slow the progression of the disease.

• The use of angiotensin-converting enzyme inhibitors (ACEIs) such as enalapril has been shown to decrease sympathetic tone and increase cardiac parasympathetic tone in dogs with mitral regurgitation 3.
• The addition of pimobendan, a phosphodiesterase inhibitor, has been found to improve heart rate variability and increase survival time in dogs with congestive heart failure caused by mitral valve disease 4, 5.
• Diuretics such as furosemide are commonly used to manage ascites and reduce fluid overload in dogs with heart failure 6, 4, 5.
• Spironolactone, a potassium-sparing diuretic, may also be used to manage ascites and reduce mortality in dogs with heart failure 6, 4.

Medication Combinations

Combining multiple medications, such as furosemide, ACEIs, pimobendan, spironolactone, and amlodipine, may result in long survival times in dogs with mitral regurgitation and congestive heart failure 4.

• A combination of pimobendan, furosemide, and enalapril has been shown to enhance cardiac autonomic modulation and increase heart rate variability in dogs with myxomatous mitral valve degeneration 5.

Tricuspid Regurgitation

Functional tricuspid regurgitation is a common finding in patients with left-sided heart disease, and its treatment is often focused on managing the underlying condition 7.

• In some cases, tricuspid regurgitation may improve spontaneously with time and pharmacological preload reduction, as well as normalization of right atrial inflow and subsequent cardiac remodelling 6.