1. Congenital Mitral Valve Disease
Seoul National University Hospital
Department of Thoracic & Cardiovascular Surgery

2. Congenital Abnormalities of Mitral Valve
Incidence
* % 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,
Shone’s 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, VSD+PS, PS
2) Symptom & signs
usually severe & if untreated, death during 1st 4~5 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
* Shone’s 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)

7. 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

9. 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.

10. 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
* Ebstein’s 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

11. 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

12. 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)

14. 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

16. Mitral Valve Repair for Multiple Leaflets
Remodeling the annulus
with Ring(1) after annular
plication with resected
posterior median leaflet(2)

17. 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

18. 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 )

19. 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

20. 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.