Congenital Mitral Valve Disease

1
Congenital Mitral Valve Disease

• Seoul National University Hospital
• Department of Thoracic Cardiovascular Surgery

2
Congenital Abnormalities of Mitral Valve

• Incidence
• 0.2-0.4 of all CHD
  
  
  
• MS 0.6 in autopsy
• MR 0.5 in autopsy
• Associated lesions ASD, VSD, PS, COA,
  LVOTO
• Mitral valve malformations may
  constitute an integral part of
• complex lesions such as hypoplastic
  left heart syndrome,
• Shones complex, atrioventricular
  canal, double inlet ventricle.
• Pathophysiology
• MS (75-80 have associated lesions)
• MR
• MSR

3
Pathophysiology of Congenital Mitral Valve Disease

• Malformation of the mitral valve apparatus
  results in mitral stenosis, insufficiency, or
  both.
• Significant flow obstruction or regurgitation of
  the mitral valve results in elevated pulmonary
  venous pressure and pulmonary congestion.
• Left untreated, pulmonary vascular occlusive
  changes and pulmonary hypertension lead to right
  ventricular hypertrophy and right heart failure.

4
Clinical Features of Congenital Mitral Valve
Disease

• Symptoms
• Fatigue, DOE, recurrent pulmonary infection,
  
• tachypnea, growth retardation, central
  cyanosis.
• ? Severely affected infants have CHF with
  gross
• pulmonary edema
• Signs
• Systolic diastolic murmur, redistribution
  of
• pulmonary vascularity, cardiac enlargement,
  
• LA enlargement, increased MPA, LV
  enlargement in MR

5
Patterns of Congenital MV Diseases

• Mitral Stenosis
• 1) Associated lesions
• 25 isolated
• 30 VSD
• 40 LVOT obstruction( 2 of COA has
  congenital MS)
• others TOF, VSDPS, PS
• 2) Symptom signs
• usually severe if untreated, death
  during 1st 45 years of life
• Mitral Insufficiency
• Often only moderate in severity in early
  life, and 1/2 patients
• come to operation until older than about 5
  years of age.

6
Types of Congenital Mitral Stenosis

• Supravalvular
• Fibrous ring
• Shones syndrome
• Valvular
• Fusion of commissure papillary muscle
• Double orifice
• Excessive valve tissue
• Annular hypoplasia( usually associated
  with HLHS)
• Subvalvular
• Single papillary muscle (Parachute valve)
• Abnormally large or numerous papillary
  muscle (Hammock valve)
• Absent papillary muscle
• Abnormalities associated with LVOTO
• Abnormal attachment of the subvalvular
  apparatus to the septum.
  
• Systolic anterior movement( usually with
  hypertrophic cardiomyopathy)

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Supramitral Ring
8
Congenital Mitral Stenosis
Functional Classification (Carpentier)

• 1. Normal papillary muscle
• 1) Commissural papillary fusion
• 2) Excessive leaflet tissue
• 3) Valvar ring
• 4) Annular hypoplasia
• 2. Abnormal papillary muscle
• 1) Parachute mitral valve
• 2) Hammock mitral valve

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Parachute-like Asymmetric Mitral Valve

• Unequal distribution of chords
• One normal and one elongated papillary muscle
• Elongated papillary muscle is displaced toward
• the MV annulus.
• The anterolateral papillary muscle is usually
• abnormal.
• Clinical implications are mitral stenosis and
• other malformations are present.

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Congenital Mitral Regurgitation

• Annulus
• 1) Dilation
• secondary due to ventricular dilation (
  rare in primary causes)
• (endocardial fibroelastosis,
  infarction, ischemia, ASD)
• Leaflets
• 1) Cleft
• 2) Leaflet defect
• hole due to localized agenesis
  (posterior)
• 3) Mitral valve prolapse
• rupture or elongated chordae tendinea
• 4) Congenital perforation or displacement
• Ebsteins anomaly of MV
• 5) Duplication of orifice
• Subvalvular apparatus
• 1) Bridge of fibrous tissue ( anomalous
  arcade) with shortened or absent chordae
• 2) Shortened chordae tendineae
• 3) Abnormal papillary muscle

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Congenital Mitral Regurgitation
Functional classification
(Carpentier)

• 1. Normal motion of the leaflet (type I)
• 1) Deformation dilatation
• 2) Clefts
• 3) Partial agenesis
• 2. Prolapse of leaflet (type II)
• 1) Absence of tendinous cords
• 2) Elongation of tendinous cords
• 3) Elongation of papillary m.
• 3. Restricted motion of leaflet (type III)
• 1) Normal papillary m.
• commissural fusion / shortness of
  cords
• 2) Abnormal papillary m.
• parachute / Hammock / hypoplasia of
  papillary m. /
  Ebstein
  malformation / double orifice

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LV Dysfunction in Mitral Regurgitation

• 1. Indicators
• 1) NYHA status
• 2) Ejection fraction
• 3) LV end-diastolic end-systolic
  dimension
• 4) Rate of rise of LV pressure
• 5) Left atrial size
• 6) Pulmonary artery pressure
• 2. Misleading
• It is possible to have LV dysfunction in
  the presence
• of normal LV dimension minimal symptoms
  due to
• afterload reduction of the regurgitant
  mitral valve.

13
Pulmonary Hypertension in MVD

• 1. Increased LAP transmitted on a retrograde
• basis into the arterial circulation
• 2. Vascular remodeling of pulmonary vasculature
  
• in response to chronic obstruction to
  pulmonary
• venous drainage(fixed component)
• 3. Pulmonary arterial vasoconstriction
• (reactive component)

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Indications for Mitral Valve Operation

• Severe symptoms signs of important pulmonary
  venous hypertension are indications of mitral
  valve anomalies
• Infancy
• 1) Mild to moderate symptoms with certainty
  without valve
• replacement supravalvular ring,
  commissure fusion
• 2) Other circumstances
• reserved only for infants with
  intractable heart failure
• Childhood
• 1) Considerations for operation are similar
• CHF
• pulmonary hypertension secondary to
  MVD
• 2) MVR should be withheld whenever possible

15
Operative Procedures for Mitral Valve

• 1. Mitral regurgitation
• 1) Eccentric annuloplasty
• 2) Ring annuloplasty
• 3) Leaflet plication chordal shortening
• 4) Suture of cleft
• 5) Valve replacement
• 2. Mitral obstruction
• 1) Resection of supravalvular ring
• 2) Open commissurotomy splitting
• 3) Correction of parachute deformity
  splitting fenestration
• 4) Valve replacement

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Mitral Valve Repair for Multiple Leaflets

• Remodeling the annulus
• with Ring(1) after annular
• plication with resected
• posterior median leaflet(2)

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Anatomy of Mitral Annulus

• C-shaped portion touches the underlying LV
• wall, the remaining 25-30 of annulus is
• intracavitary.
• Muscular representation is the basis for
• geometric relationship, being more elliptic
• in systole and circular in diastole.
  
• To be a support for the leaflet attachment
  
• To insulate electrically the atrium from
  ventricle

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Aims for Mitral Valve Annuloplasty

• Reduce annular dilation mitral valve area
  
• Increase the leaflet coaptation
• Reinforce the annulus sutures when part of
• the valve has been resected
• Prevent future dilation of annulus
• ( Stabilization of the posterior annulus )

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Complications of Mitral Annuloplasty Ring

• 1. Postoperative valvular incompetence
• most common mild in 15 by Echo
• 2. LVOT obstruction 3
• 3. Suture line dehiscence 2
• 4. Dehiscence of prosthetic ring, fracture,
  hemolysis
• 1
• 5. Aortic regurgitation infrequent

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Postoperative Course Results

• Mortality
• Usually higher than adult ( LCO,
  pulmonary hypertension)
• Complication
• Low cardiac output
  Neurologic complication
• Bleeding and infection
  Arrhythmia
• Pulmonary insufficiency
• Risk factors
• Young age
• Preoperative functional status
• Associated cardiac anomaly
• Long-term result
• Most survivors improve functionally.
• Better for mitral valve repair than
  replacement
• Residual stenosis or regurgitation is
  present in most can progress.