What is the treatment for a double mitral valve?

Treatment of Double Mitral Valve

Surgical intervention is the primary treatment for double mitral valve (DOMV), with the specific approach depending on the type of DOMV, associated valve dysfunction, and presence of concomitant cardiac abnormalities. 1, 2

Diagnosis and Assessment

• Double-orifice mitral valve is a rare congenital malformation characterized by two orifices in the left atrioventricular valve area, each with independent chordal attachments to papillary muscles 1
• Echocardiography (particularly transthoracic echocardiography) is the primary diagnostic tool, sufficient in most cases to define the type, anatomy, and associated lesions 2
• Transesophageal echocardiography may be required in some cases for definitive diagnosis 2
• Three main types of DOMV exist: complete bridge type (most common), hole type, and duplicate mitral valve type 2

Treatment Approach Based on Valve Function

For DOMV with Mitral Stenosis (MS)

• Mechanical correction is necessary in most symptomatic patients with DOMV and significant MS 3
• If MS is the predominant lesion with favorable valve anatomy, percutaneous balloon mitral valvotomy may be considered first 3
• When MS is combined with other valve diseases (e.g., aortic stenosis), surgical intervention is typically required 3
• Cardiac catheterization is often necessary to fully assess hemodynamics, especially when exercise testing is needed to evaluate symptoms 3

For DOMV with Mitral Regurgitation (MR)

• Surgical intervention is indicated for symptomatic patients with severe MR 4
• Surgery should be considered in asymptomatic patients with severe MR if any of the following are present: left ventricular dysfunction, new onset atrial fibrillation, or pulmonary hypertension 4
• Mitral valve repair is strongly preferred over replacement when technically feasible 4, 5

Important Surgical Considerations

• The fibrous "bridges" between the orifices should NOT be transected surgically, as they are composed of mitral leaflet tissue and chordae, not fibrous adhesions - cutting them can cause iatrogenic mitral regurgitation 1
• The underlying tensor apparatus anomalies must be carefully evaluated as they are always present in DOMV 1
• Repair techniques should be based on specific pathology and may include non-resection techniques or resection with annuloplasty ring 4
• For patients at high surgical risk, percutaneous edge-to-edge repair may be considered, though experience with this approach in DOMV is limited 4

Management of Associated Conditions

• When DOMV is associated with tricuspid regurgitation (TR) and mitral valve surgery is performed, concomitant tricuspid annuloplasty should be considered 3
• If DOMV is associated with atrial septal defects (common association), these should be addressed during the same procedure 2
• In cases of mixed valve disease (e.g., DOMV with both stenosis and regurgitation), management follows the recommendations for the predominant lesion 3

Follow-up Protocol

• Asymptomatic patients with moderate MR should have yearly clinical follow-up with echocardiography every 2 years 4
• Asymptomatic patients with severe MR should have clinical evaluation every 6 months with annual echocardiography 4
• After repair or replacement, a baseline ECG, X-ray, and echocardiography should be established for future comparison 4

Common Pitfalls

• Failure to recognize the underlying tensor apparatus anomalies can lead to inappropriate surgical techniques 1
• Mistaking the fibrous bridges for adhesions and cutting them can cause severe iatrogenic mitral regurgitation 1
• Underestimating the severity of valve dysfunction due to the complex hemodynamics of double orifice anatomy 3
• Delaying intervention until symptoms develop or left ventricular dysfunction occurs can lead to poorer outcomes 4

Remember that DOMV is rare, and management should be undertaken at centers with experience in complex congenital heart disease and valve repair techniques.