What is myxomatous mitral valve disease?

From the Guidelines

Myxomatous valve disease is a degenerative condition that requires careful management to prevent morbidity and mortality, and the most recent guidelines recommend a personalized approach to treatment, with surgical intervention recommended when severe regurgitation develops, especially with symptoms or signs of left ventricular dysfunction, as stated in the 2022 study 1.

Diagnosis and Treatment

Myxomatous valve disease is a condition affecting heart valves, most commonly the mitral valve, where the valve tissue becomes floppy and stretchy due to abnormal accumulation of proteoglycans. This condition is the most common cause of mitral valve prolapse, where the valve leaflets bulge back into the left atrium during contraction.

• Most patients with myxomatous valve disease remain asymptomatic and require no specific treatment.
• For those who develop symptoms like shortness of breath, palpitations, or chest discomfort, management depends on severity.
• Beta-blockers such as metoprolol (25-100 mg twice daily) may help control symptoms by reducing heart rate and contractility, as mentioned in the example answer.
• Patients with significant regurgitation require regular echocardiographic monitoring every 1-2 years to assess disease progression, according to the 2008 guidelines 2.

Surgical Intervention

Surgical intervention (valve repair or replacement) is recommended when severe regurgitation develops, especially with symptoms or signs of left ventricular dysfunction, as stated in the 2022 study 1.

• The decision to operate is best made before surgery based on the symptoms and preoperative testing, as mentioned in the 2008 guidelines 2.
• Intraoperative transesophageal echocardiography may provide additional information about the mechanism of regurgitation and may be helpful to direct the decision whether to repair or replace the valve, as stated in the 2008 guidelines 2.

Antibiotic Prophylaxis

Antibiotic prophylaxis is no longer routinely recommended for most patients with myxomatous valve disease unless they have a history of endocarditis, as mentioned in the example answer.

• The condition results from abnormal collagen production and degradation, with possible genetic factors involved in some cases, particularly with connective tissue disorders like Marfan syndrome, as stated in the 2015 guidelines 3.

Imaging Techniques

Transthoracic echocardiography is the most commonly used imaging test for MR; transesophageal echocardiography is often needed to better define morphology and MR severity, and is essential for guiding transcatheter therapies for MR, as stated in the 2021 study 4.

• Multidetector computed tomography has become the standard to assess whether transcatheter valve replacement is an option because of its ability to assess valve sizing, access, and potential left ventricular outflow tract obstruction, as mentioned in the 2021 study 4.

From the Research

Myxomatous Valve Disease

• Myxomatous mitral valve disease is a spectrum that ranges from fibroelastic deficiency to Barlow's disease, as stated in the study 5.
• The disease can cause valvular stenosis, regurgitation, or both, due to structural abnormalities of the mitral valve, involving different components of the mitral apparatus 6.
• Advanced myxomatous degeneration of the mitral valve is defined as a degenerative process whereby both leaflets are voluminous and aneurysmal and the mitral annulus diameter exceeds 40 mm and has posterior displacement 7.

Diagnosis and Management

• Diagnosis of myxomatous valve disease has been greatly aided by the use of 3-dimensional echocardiography, which improves the accuracy of lesion localization and the quantification of the associated mitral regurgitation 5.
• Two- and three-dimensional transthoracic and/or transesophageal echocardiography, as well as magnetic resonance imaging, are the major diagnostic tools for the diagnosis of a cardiac myxoma 8.
• Surgical resection with mitral valve defect repair is the commonest remedy for mitral valve myxoma when mitral valve function can be preserved, and the mitral valve should be replaced when necessary 8.
• Mitral valve repair for advanced myxomatous degeneration provides excellent early functional results, but late recurrent regurgitation is common, despite correction of dilated and displaced mitral annulus and leaflet prolapse 7.

Treatment Outcomes

• Patients with mitral valve myxoma show good response to surgical treatment during the follow-up, with a mean follow-up of 17.0 ± 28.4 months after the operation 8.
• The survival at 10 years was 92% +/- 3% for patients who underwent mitral valve repair for advanced myxomatous degeneration 7.
• The freedom from reoperation at 10 years was 93% +/- 3%, and the freedom from recurrent moderate or severe mitral regurgitation at 10 years was 80% +/- 5% 7.