MITRAL VALVE ABNORMALITIES U2 L1

How can mitral valve disease in a pediatric patient be classified?

As either:

1. Congenital

2. Acquired

List the 3 ways mitral valve disease can be subdivided.

• Primarily stenotic

• Primarily regurgitant

• Combination of stenosis and regurgitation

List the 3 mitral valve abnormalities that are more stenotic.

• Congenital mitral stenosis

• Mitral arcade

• Parachute mitral valve

Which mitral valve abnormality is more regurgitant, and what is its incidence?

Mitral valve prolapse — 5–15%.

How may a Double Orifice Mitral Valve function, and what is its incidence?

It may be normal, stenotic, and/or regurgitant.

Incidence: 1.0%

How common are congenital mitral valve deformities?

They are rare.

Is congenital mitral incompetence more or less common than congenital mitral stenosis?

It is even rarer.

What is the male-to-female prevalence ratio for congenital mitral valve abnormalities?

1.5:1 to 2.2:1.

Are congenital mitral valve abnormalities usually isolated?

They can occur in isolation, but are more commonly associated with other congenital heart disease.

List the 4 left-heart obstructions that define Shone syndrome.

• Parachute mitral valve

• Supravalvular mitral stenosing ring

• Subaortic stenosis

• Coarctation of the aorta

What is Shone complex?

A series of left-heart obstructive lesions that do not meet the original definition of Shone syndrome.

List the 4 abnormalities that may cause congenital mitral stenosis.

• Supravalvular mitral stenosing ring

• Parachute mitral valve

• Mitral arcade

• Double orifice mitral valve

What is a supravalvular mitral stenosing ring, and where is it located?

A membrane in the left atrium located:

• Above the mitral annulus

• Below the left atrial appendage

Can a supravalvular mitral stenosing ring be obstructive or nonobstructive?

Yes. It can be either.

What percentage of supravalvular mitral stenosing rings occur with left-sided obstructive lesions?

90%

List the 3 effects a supravalvular mitral stenosing ring can have on the heart.

• Flow disturbances and damage to the MV leaflets

• High left atrial pressure

• Mitral regurgitation is usually present

List the 3 clinical findings of a supravalvular mitral stenosing ring.

• Shortness of breath

• Diastolic rumble with a systolic component from MR

• Pulmonary congestion and cardiomegaly on X-ray

List the 5 lesions associated with a supravalvular mitral stenosing ring.

• Left SVC

• VSD

• Coarctation of the aorta

• ASD

• Shone complex

What happens to the LA with a supravalvular mitral stenosing ring?

The LA becomes enlarged

In what views and phase of the cardiac cycle can the membrane be seen?

In diastole from:

1. PLAX

2. Apical views

How do the mitral valve leaflets appear with a supravalvular mitral stenosing ring?

They appear thickened with limited excursion.

What color Doppler finding is seen with a supravalvular mitral stenosing ring?

Flow acceleration just above the mitral annulus.

List the 3 additional things that should be assessed on echo.

• ASD

• MR

• RVSP

What is the differential diagnosis for a supravalvular mitral stenosing ring?

Other forms of congenital mitral stenosis.

How is a supravalvular mitral stenosing ring treated?

• Surgical resection of the membrane

• Mitral valve repair or replacement if the valve is damaged

What is a parachute mitral valve?

The mitral valve chordae insert into a solitary papillary muscle.

Which papillary muscle do the chordae typically insert into in a parachute mitral valve?

The posteromedial papillary muscle.

What happens to the anterolateral papillary muscle in a parachute mitral valve?

It is reduced or absent.

What does it mean that a parachute mitral valve has a functionally unilateral papillary muscle?

Functionally, the valve's chordae are supported by one papillary muscle.

Can 2 papillary muscles still be present with a parachute mitral valve?

Yes. They may be asymmetric, with one prominent papillary muscle and the other representing remnants of the congenital malformation.

How are the chordae abnormal in a parachute mitral valve, and what can this cause?

The chordae may be abnormal in length and thickened, limiting systolic and diastolic motion and producing:

1. Mitral stenosis

2. Mitral regurgitation

How may an adult with a parachute mitral valve present?

The patient may have:

• Normal hemodynamics, or

• Significant mitral stenosis or regurgitation on Doppler

What type of associated cardiovascular abnormalities should make you think of Shone syndrome or Shone complex in a patient with a parachute mitral valve?

LV outflow-tract and aortic-arch abnormalities.

List the 3 associated defects and their frequencies with parachute mitral valve.

• Aortic valve stenosis — 32%

• ASD — 54%

• Hypoplastic left heart — 19%

How common is an isolated parachute mitral valve?

Less than 1% of cases.

What is the main pathology of a parachute mitral valve?

A single dominant papillary muscle with shortened/thickened chordae converging onto that papillary muscle.

What are the 2 key PSAX findings of a parachute mitral valve?

• At the mid-papillary level — single papillary muscle

• At the basal level — parachute-shaped leaflets

What is seen in the LV long-axis view with a parachute mitral valve?

The chordae may be shortened/thickened or elongated and converge toward a single papillary muscle.

List the 2 four-chamber findings of a parachute mitral valve.

• Thickened MV leaflets with thickened/dysplastic chordae

• Pear-shaped mitral configuration with a diastolic dome shape

What is the differential diagnosis, treatment, and prognosis for a parachute mitral valve?

• Differential: Other congenital mitral stenosis

• Treatment: Mitral valve replacement

• Prognosis: Good

What is another name for a mitral arcade?

Hammock mitral valve

What are the papillary muscles and chordae like in a mitral arcade?

• 2 elongated papillary muscles

• Shortened dysplastic chordae that attach directly to the mitral leaflets

How do the chordae tendineae typically appear in a mitral arcade?

They are short, thick, and fused, making it look like the papillary muscles attach directly to the mitral leaflets.

Why can a mitral arcade cause both mitral stenosis and regurgitation?

The arc-like papillary muscles and short chordae cause:

• Restricted mitral leaflet motion

• Incomplete leaflet coaptation

This can produce both MS and MR.

Is mitral arcade more stenotic or regurgitant?

It is more stenotic, with regurgitation also present.

What are the main hemodynamics of a mitral arcade?

Mitral stenosis hemodynamics.

What is the clinical presentation of a severe mitral arcade?

Severe CHF related to progressive:

1. MR

2. MS

What does the slide say about mortality and survival with mitral arcade?

Early mortality is high, and survival into adulthood is extremely rare.

List the 3 main pathologic features of a mitral arcade.

• Short, thick, fused or absent chordae

• Elongated papillary muscles

• Fibrous tissue connecting the papillary muscles and mitral leaflets in an arc-like or hammock configuration

What PLAX findings may be seen with a mitral arcade?

Elongated papillary muscles appear directly attached to the mitral leaflets because the chordae are very short, thick, or absent.

What PSAX finding may identify the fibrous band in a mitral arcade?

A hyperechoic structure between the 2 papillary muscles, representing the interconnecting fibrous band.

What mitral leaflet-motion abnormality may occur with a mitral arcade?

Restricted systolic and/or diastolic motion, usually involving the anterior mitral leaflet.

What is the differential diagnosis, treatment, and prognosis for a mitral arcade?

• Differential: Other congenital mitral stenosis

• Treatment: Mitral valve replacement

• Prognosis: Good

What is a Double Orifice Mitral Valve (DOMV)?

A mitral valve with one annulus but 2 separate openings divided by a fibrous bridge.

What embryologic abnormality causes DOMV?

Abnormal endocardial cushion development.

How can a DOMV function?

• Function normally

• Be stenotic

• Be regurgitant

How does the clinical presentation of DOMV depend on valve function?

• Stenosis → mitral stenosis symptoms

• Regurgitation → mitral regurgitation symptoms

• Normal function → asymptomatic/incidental finding

List the 4 defects associated with DOMV.

• AV canal defects

• Coarctation of the aorta

• PDA

• Bicuspid aortic valve

In which views is DOMV best seen?

• Parasternal short axis

• Apical 2-chamber

What sweeps should be performed when evaluating DOMV?

Use multiple parasternal and subcostal short-axis sweeps and apical views.

What should be evaluated in each orifice of a DOMV?

• Regurgitation

• Stenosis

List the 3 things imaging should determine in DOMV.

• Type of DOMV

• Function of the abnormality

• Anatomy of the tensor apparatus

What is medical therapy used for in symptomatic DOMV?

To treat symptoms of:

1. Heart failure

2. Pulmonary congestion

How may stenotic DOMV be treated?

Treatment may include:

1. Percutaneous transcatheter balloon dilation

2. Surgical mitral valvuloplasty

3. Mitral valve replacement

How may a regurgitant DOMV be surgically repaired?

With leaflet plication.

Why can surgically closing one orifice of a DOMV be a problem?

It can reduce the total mitral valve area, resulting in stenotic flow.

What is mitral valve prolapse (MVP)?

One or both mitral leaflets arch excessively and pass beyond the annulus into the left atrium during systole.

How common is MVP in adults versus children?

• Adults: Common finding

• Children: Infrequent outside of connective-tissue disease

What valve degeneration characterizes MVP?

Progressive myxomatous degeneration of the valve apparatus.

List the 3 structural changes associated with myxomatous degeneration.

• Expansion/thickening of the valve leaflet

• Elongation of the chordal apparatus

• Annular dilation

Which mitral leaflet is most commonly affected by myxomatous degeneration?

The posterior leaflet, although either leaflet can be affected.

When does mitral valve prolapse occur during systole?

When the leaflets slip past the coaptation zone.

What leaflet displacement defines MVP?

>2 mm displacement in the long-axis plane.

What complications can MVP eventually cause?

• Mitral regurgitation

• Chordal rupture → flail leaflet

What is primary MVP?

Myxomatous degeneration of the mitral valve without a connective-tissue disorder.

What is secondary MVP?

MVP associated with a connective-tissue disorder.

What inheritance pattern is associated with MVP?

Multiple genetic abnormalities may produce a common phenotype, and there is a family inheritance pattern.

How common is at least mild MVP in patients with Marfan syndrome?

Approximately 75%.

List the 2 other connective-tissue disorders associated with an increased prevalence of MVP.

• Ehlers-Danlos syndrome

• Loeys-Dietz syndrome

What is syndromic MVP?

MVP associated with a connective-tissue disorder.

What patient measurement should be documented during an MVP echo?

Blood pressure.

List the 4 main views used to diagnose MVP and evaluate the tensor apparatus.

• PLAX

• PSAX LV

• Apical long axis

• Apical 2-chamber

In which view should MVP displacement be measured?

PLAX.

List the 2 measurement criteria given for MVP.

• Leaflet displacement >2 mm

• Leaflet thickness >5 mm

What 2 rupture abnormalities should be looked for with MVP?

• Chordal rupture

• Papillary muscle rupture

What should be done with the MR associated with MVP?

Quantify the amount of mitral regurgitation.

What should be done if the MR jet is eccentric?

Use off-axis imaging.

What 2 timing patterns may an MVP MR jet have?

• Holosystolic

• Late systolic

What direction is the MR jet with posterior leaflet prolapse?

Anteriorly directed.

What direction is the MR jet with anterior leaflet prolapse?

Posteriorly directed.

What direction may the MR jet have with bileaflet prolapse?

It may be central or eccentric.

List the 4 additional considerations when evaluating MVP.

• Regurgitation may be progressive

• Perform Pickelhaube assessment

• Rule out endocarditis

• MVP can be associated with embolic events

What is the Pickelhaube sign?

Tugging of the posteromedial papillary muscle during mid-systole, pulling the adjacent posterobasal LV wall sharply toward the apex and producing a spiked configuration.

What Pickelhaube annular spike velocity may be a risk marker for malignant arrhythmias?

>16 cm/s in patients with myxomatous mitral valve disease and bileaflet MVP.

What tissue Doppler sample-volume size is used for Pickelhaube assessment?

5 mm.

Which annuli are evaluated from the apical 4-chamber view for Pickelhaube?

• Medial annulus

• Lateral annulus

Which annuli are evaluated from the apical 2-chamber view for Pickelhaube?

• Inferior annulus

• Anterior annulus

Which annulus is evaluated from the apical long-axis view, and where is the highest Pickelhaube velocity usually found?

The posterolateral annulus, which is also where the highest Pickelhaube signal velocity is typically found.

List the 4 treatments given for MVP.

• Medical management

• Prophylaxis

• Transcatheter edge-to-edge repair

• Mitral valve replacement

List the 8 findings associated with congenital mitral valve abnormalities.

• ASD

• Coarctation of the aorta

• Subaortic stenosis

• Bicuspid aortic valve

• LSVC

• Left-sided hypoplasia

• Shone complex or Shone syndrome

• Pulmonary hypertension