Myxomatous mitral valve degeneration

Last revised by Joachim Feger on 17 Dec 2021

Myxomatous mitral valve degeneration, myxomatous degeneration of the mitral valve, myxomatous mitral valve disease or simply myxomatous mitral valve is a non-inflammatory progressive alteration of the mitral valve structure associated with mitral valve prolapse and mitral insufficiency.

Myxomatous mitral valve degeneration is also termed ‘Barlow disease’ yet the name actually refers to the clinical syndrome describing a late systolic murmur and a non-ejection systolic click associated with mitral valve prolapse 1.2.

Myxomatous degeneration of the mitral valve is a common form of valvular heart disease with an estimated frequency of 0.6-2.4% 1 and seems to be more common in females, but symptoms seem to be more severe in men 2.

Myxomatous degeneration of the mitral valve is closely associated with the following conditions 1-6:

Patients can present with a systolic click and a mid to late systolic murmur on auscultation indicating mitral valve prolapse 1,2.

Complications of myxomatous degeneration of the mitral valve include the following conditions 1-6:

Myxomatous degeneration of the mitral valve is a histopathological diagnosis and characterized by myxomatous altered thickened mitral leaflets and involvement of the chordae tendineae leading to a loss of mechanical leaflet integrity 3. The posterior mitral leaflet is more frequently affected 2.

On gross appearance, myxomatous degeneration is characterized by ample leaflet thickening not only involving the valve but also the chordae tendineae 1.

Microscopically myxomatous mitral valve degeneration shows the following features 1-3:

  • thickening and proliferation of the spongiosa
  • accumulation and pooling of glycosaminoglycan
  • disruption of the fibrosa by the myxomatous extracellular matrix with cystic appearance
  • collagen fragmentation of the fibrous layer

Some cases have been linked to a familial inheritance mapped to the Xq28 location 3,7.

The main imaging feature of myxomatous mitral valve degeneration is a thickening of one or both mitral leaflets 3.

Echocardiography is considered is usually the first-line imaging modality for the evaluation of mitral valvular disorders. It can identify mitral valve thickening, assess leaflet coaptation, depict flail leaflets and other associated conditions as mitral prolapse and mitral insufficiency as well as mitral annular dilation 5.

Due to good spatial resolution, cardiac CT can assess the thickness of the mitral leaflets and can detect leaflet flail. It can also identify calcification of the chordae tendineae.

Cardiac MRI can detect valvular thickening and associated findings as mitral prolapse, mitral insufficiency and mitral annular disjunction as well as complications e.g. chordae tendineae rupture 5.

The radiological report should include a description of the following features:

Management is subject to complications but in the setting of mitral valve regurgitation, it is the most common indication for mitral valve repair or replacement 1,3. In asymptomatic individuals, without mitral regurgitation, the management will consist in watchful waiting 1.

The clinical presentation and significance of systolic click and late systolic murmur on auscultation have been first demonstrated by JB Barlow and WA Pocock in 1963 8.

Conditions mimicking the imaging appearance of myxomatous mitral valve degeneration include:

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