Download Mitral Valve Anatomy-important Anatomic Relationship

Mitral Valve Anatomy-important Anatomic Relationship
 The functional components of the mitral valve
apparatus include:
 Annulus
 Leaflets
 Chordae
 Papillary muscles
 LV wall
 Abnormality in any of these component will result
in mitral regurgitation.
Anterior Annulus
Anterior leaflet
Anteromedial commissure
Posterolateral
commissure
Posterior leaflet
(3 lobes)
Posterior
Annulus
SLIDE 3 - PICTURE
FIGURE 1
Chordae tendinae
Medial papillary
muscle
Lateral papillary
Muscle
MITRAL VALVE
Left main
Coronary artery
Left
coronary
sinus
Noncoronary
sinus
Anterior leaflet
Intervalvular
trigone
Circumflex
coronary artery
Anterolateral
papillary muscle
Posterior leaflet
Secondary
Chorda tendinea
Posteromedial
papillary muscle
Primary chorda
tendinea
Tertiary chorda
tendinea
Coronary Sinus
DOG LV
DIASTOLE
OBSERVED
Fiber Dimensions Calculated
Spherical LV Model (`100g)
SYSTOLE
The left ventricular wall
composed of muslce fibers,
connective tissue, fat neurovascular structures and
lymphatics
Photomontages assembled from electron
micrographs of dog LV cells are from
control (A), congestive heart failure due to
mitral regurgitation (B), and recovery
state after successful mitral valve surgery
(C).
Electron micrograph of adult LV canine
myocardium. Long axes of several cells
cross the figure from left to right.
Arrows mark the location of
boundaries between adjacent cells.
Large open spaces are capillaries
perfused with fixative.
Ephysilus
Weave
Myofibril
Stranos
Myocyte
Capillary
Tendon
Struts
Schematic illustration of substructure of the connective tissue matrix of
the myocardium.
Systolic Torsion of LV
Asymmetry of fiber radii, sarcomere
length and electrical activation allows
torsion of the apex relative to the base.
Base
Endocardium
Apex
Epicardium
Model for generation of torque for
LV wall.
Vectors for force
generation at the epicardial and
endocardial
surfaces
could
neutralize each other.
The
epicardial fibers at the epicardial
surface have a longer radius and a
more powerful moment arm.
Sarcomere lengths, activation time,
and infolding of the wall contribute
to heterogencity of the relation
between structure and function
between the inner and outer regions
of the wall. Differences in the total
force generated are believed
responsible for the LV systolic
twist.
Classification of Structural Valve Abnormalities
Type
I
Abnormality
Normal leaflet motion
Annular dilation
Leaflet perforation
II
Leaflet prolapse
Chordal rupture
Chordal elongation
Papillary muscle rupture
Papillary musle elongation
III
Restricted leaflet motion
Commissure fusion
Leaflet thickening
Chordal fusion and thickening
Mechanism of mitral regurgitation
Etiology of Mitral Regurgitation in Patients
Undergoing Valve Repair
Etiology
Incidence
Degenerative
87%
Endocarditis
6%
Rheumatic
4%
Miscellaneous
3%
Mechanism
Valvular Prolapse
Incidence
94%
Posterior leaflet prolapse
66%
Anterior leaflet prolapse
10%
Bileaflet prolapse
18%
Ruptured chordae tendineae
74%
 Pathophysiological Changes in Mitral Regurgitation
 Decrease left ventricular impedance
 Increase left ventricular end-diastolic
volume
 Increase stroke work and afterload
 Decrese ejection fraction and increase left
ventricular end-systolic dimension
 Myocardial fibrosis and end-stage
cardiomyopathy
 The Natural History of Mitral Regurgitation
 Mitral regurgitation is a progressive
disease
 With an increase on average of 7.5
ml/year for regurgitant volume and of
5.9 mm2/year for the effective
regurgitant orifice.
 The progression of mitral regurge also
cause progression of LV remodelling at
the same rate.
 Importantly, progression is not
uniform, 10% of mitral regurgitation
regress spontaneously
 The rate of reversal varies 6 weeks
to 1 year
 The Natural History of Severe Mitral Regurgitation
 High morbidity at 10 year:
 Atrial fibrilliation - 30%
 Heart Failure
- 60%
 Sudden death at the rate of 1.8%
per year
 Timing of Surgery
 What information is needed to
define the timing of mitral surgery?
 Symptoms-Functional Class Impact
of Pre-operqtive symptoms on
survival after mitral surgery
100-
90+2
76+5
Survival (%)
8073+3
60NYHA I-II
NYHA III-IV
40-
48+4
20-
P<0.0001
0
Years
N8
I-II
0
199
1
192
2
187
III-IV
279
249 236
3
184
4
181
5
169
6
125
7
95
8
63
9
42
10
34
227 211
201
174 183
103
74
51
Figure 1. Overall postoperative survival compared between patients in
NYHA Class I/II and patients in Class III/IV – Numbers at bottom indicate
patients at risk.
 Left Ventricular Function
 Ejection Fraction
 Left ventricular and systolic
dimension
 Assessed by echocardiography
100
75%
Survival (%)
80
53%
60
40
Ef
Ef 50-60%
EF<50%
P-0.0001
20
0
0
2
4
32%
Years
6
8
10
 Degree of mitral regurgitation-hymodynamics
 Regurgitant volume (R.Vol.)
 Effective regurgitant orifice (ERO)
 Assessed by quantitative doppler echo
 The respective thresholds for severe mitral
regurgitation are (R.Vol.) > 60 ml. and ERO
> 40mm2
 Timing of Surgery
 Translate
into_when
the
patient
seen_promptly
provided
no
major
comonbidities
 The concept of waiting fro signs of
early LV dysfunction is not advised
QUESTION:
Should we advise follow-up with medical treatment?
ANSWER:
NO, even if ejection fraction is low.
 Operative mortality is not excessive.
 Post operative complications are often
delayed.
 The precision of the prediction of the
outcome is imperfect.
 Mitral Valve Surgery
 The optimal intervention for mitral
surgery is valve repair.
 Superior hemodynamics and ventricular
function.
 Less distortion of ventricular shape.
 Avoidance of prosthetic
related complications.
valve
 Excellent long term clinical outcome.
and
 Mitral Valve Repair
 Leaflet plication
McGoon
Plication
 Posterior leaflet excision [carpentier]
 Posterior leaflet prolapse
2 to ruptured or elongated chordae.
Excise unsupported
leaflet
Posterior
leaflet
Ruptured
chordae
Repair annulus
Repair
leaflet
Supported repair
Subvalvar apparatus inspection with a nerve hook.
The middle portion of the leaflets is identified
The central stitch is used to check the symmetricity
of the orifices.
 Edge-Edge Technique [Alfieri]
 Innovative method for mitral valve repair.
A running suture along the free edge of the leaflets is done.
 Chordal Repair
 Anterior leaflet prolapse
Excise unsupported
leaflet
Anterior
leaflet
Ruptured\
Chordae
tendineae
Mobilize apposing
posterior leaflet
Posterior leaflet
Transfer supported
posteior leaflet
Attach posterior
leaflet and
repair annulus
Completed repair
CONCLUSION:
 Mitral regurgitation is a surgical issue.
 Timing of mitral surgery still remained one
of the most vexing problems of clinical
cardiac science.
 The concept of waiting for signs of early LV
dysfunction not exists anymore.
 The outlook is poor for patients who are
treated medically.
Chronic severe
Mitral regurgitation
Symptoms
No symptoms
Echocardiography
Left Ventricular ejection
Fraction >0.60
and end-systolic
Dimension <45 mm
Left Ventricular ejection
Fraction >0.60
or end-systolic
Dimension >45 mm
Echocardiography
Mitral valve
reparable
Mitral valve
not reparable
Ejection fraction
>0.30
No atrial fibrillation
or pulmonary
hypertension
Clinical and
Echocardiographic
Follow-up
Ejection fraction
>0.30
Atrial fibrillation
or pulmonary
hypertension
Mitral-valve surgery
(valve repair preferred
if technically feasible)
Management of Chronic Severe Mitral Regurgitation
Mitral-valve
replacement
Mitral-valve
replacement
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