Mitral valve surgical anatomy DR NIKUNJ R SHEKHADA (MBBS ,MS GRN SURG , DNB CTS SR

1. SURGICAL ANATOMY OF MITRAL
VALVE
BY DR NIKUNJ
(CTS RESIDENT STAR HOSPITAL)
(Coordinator:DR P.SATYENDRANATH PATHURI)
(11/9/18)

4. THE ATRIO-VALVULAR JUNCTION
• The junction between the atrium and the valvular tissue is usually well delineated
by the different colors of these structures: the atrium is slightly pink, and the
leaflets are yellowish.
• This junction defines the hinge where the motion of the leaflets is initiated.
• The hinge allows demar- cation of the annulus fibrosus, which is not visible from
an atrial view.

5. ANNULUS FIBROSUS
• actually a discontinuous band of connective tissue that exists only in some parts of the
attachment of the posterior leaflet.
• The annulus in actuality does not exist at the attachment of the anterior leaflet because the
leaflet tissue is continuous with the aorto- mitral curtain that extends from the aortic valve
annulus to the base of the anterior leaflet

6. • At each extremity of the base of the anterior leaflet, the atrio-valvular junction is
reinforced by two dense triangular fibrous structures: the anterolateral and
posteromedial fibrous trigones.

7. • The shape of the annulus varies throughout the cardiac cycle
• During diastole, the shape is grossly circular . During systole, the annulus has a kidney
shape

8. • Instead of having a planar configuration, the annulus has a three-dimensional saddle-
shape configuration. The two lowest points are located at the fibrous trigones and the
• two highest points are located at the midpoints of the anterior and posterior annuli.
• The plane of the mitral valve annulus makes a 120° angle with the plane of the aortic valve
annulus.

9. The 26% ± 3% reduction of the mitral valve orifice area during systole results from the
contraction of the base of the heart and the displacement of the aorto-mitral curtain towards
the center of the orifice.

10. THE LEAFLETS
• The mitral valve comprises two
leaflets—1)anterior
• 2)posterior
• separated by two commissures.
These leaflets are the opening and
closing structures of the valve
• Optimal closure implies a precise
fitting between the surface area
of the leaflets and the orifice area
of the mitral valve.
• Although the anterior and
posterior leaflets have a dif-
ferent size and shape , with the
anterior leaflet more extended
vertically and the posterior leaflet
more extended transversally, they
have a similar surface area.

11. • The basal insertion of the
anterior leaflet occupies approx-
imately one third of the
circumference of the mitral
valve
• The remaining two thirds of the
circumference attaches to the
posterior leaflet and the
commissural tissue.
• The anterior leaflet is primarily
related to the left ventricular
outflow tract via the aorto-
mitral curtain whereas the
posterior leaflet is related to the
muscular parietal base of the
left ventricle. As a result of this
configuration, the maximum
stress during systole is concen-
trated at the midline of the
posterior leaflet

12. ANTERIOR LEAFLET
• ANTERIOR LEAFLET, also called the aortic leaflet, has a trapezoidal shape. Its base,
which measures 32 ± 1.3 mm, is inserted on the aorto-mitral curtain and the
adjacent fibrous trigones. The free edge presents with a slightly convex curvature.
At the midline, the height of the anterior leaflet averages 23 mm.
• From the base to the margin, two zones are clearly appa ent.
• 1)The proximal zone, called the atrial zone, is regular, thin, and translucent.
• 2)The distal zone, called the zone of coaptation or rough zone, is irregular and
thicker because of the numerous chordae attached to its ventricular side. The two
zones have a similar surface area.
• The surface of coaptation, which has a height of 7 to 9 mm,
• During diastole, the anterior leaflet divides the left ventricle into two functional
areas, the inflow chamber and the outflow tract.

13. • The surface of coaptation, which has a height of 7 to 9 mm

14. POSTERIOR LEAFLET
• The posterior leaflet is inserted approximately
on two thirds of the annulus, to the crest of
the ventricular wall. The free edge is deeply
scalloped by two indentations ,separating
three segments: the anterior, middle, and
posterior scallops are also called P1, P2, and
P3, respectively, to facilitate valve analysis. By
convention, the corresponding areas of the
anterior leaflet are called A1, A2, and A3, and
the commissures AC and PC.
• The size of the scallops of the posterior leaflet
differs. The largest is the middle scallop (P2)
and the smallest is the anterior scallop (P1)
• the posterior leaflet presents two zones from
its base to the free margin: the atrial zone is
smooth and translucent and the coaptation
zone is thicker

15. • THE COMMISSURES may be described
as a functional entity consisting of two
different structures: the commissural
leaflet, which provides continuity
between the anterior and posterior
leaflets, and the coaptation surfaces
with adjacent anterior and posterior
leaflets.
• The commissural leaflet is a small,
triangular segment of leaflet tissue. Its
base is attached to the annulus and its
free edge is supported by one or two
characteristic fanlike chordae.
• As a result of this configuration, the
junction between the anterior and
posterior leaflets does not reach the
annulus but forms a Y-shaped line of
coaptation.

17. THE SUSPENSION SYSTEM
• The leaflets are connected to the
ventricular cavity by a suspension system
called the subvalvular apparatus. The
suspension system has two functions:
• one is to facilitate he opening of the
leaflets during diastole (active opening);
• the other is to prevent the upward
displace- ment of the leaflets above the
plane of the annulus during systole.
• To accomplish these two functions, the
suspension system consists of two
structures with different charcteristics:
• THE PAPILLARY MUSCLES with contractile
properties and
• THE CHORDAE TENDINEAE with elastic
properties.

18. THE PAPILLARY MUSCLES
• insert on the ventricular wall, are usually
organized into two groups, designated
posteromedial and anterolateral, positioned
below the corresponding commissures
I—Large and bulky with a single head generating
numerous chordae.
II—Large and bulky with multiple heads
attaching numerous chordae.
III—Narrow and having few chordae.
IV—Arch shape from which arise several
chordae; the arch may form an arcade with
several trabeculations attached to the
myocardium.
V—Adherent to the ventricular wall and
generating multiple chordae
.

19. • The anterior papillary muscle most
often has a type I configuration
with occasionally an adjacent type
III papillary muscle attaching the
commissural chordae.
• The posterior papillary muscle
usually has a type II configuration
with one head attaching the
chordae of the anterior leaflet, one
head attaching the commissural
chordae, and one head attaching
chordae of the posterior leaflet.

20. • The papillary muscles are implanted on the muscular wall of
the left ventricle at a junction situated approximately 1/3
from the apex and 2/3 from the annulus
• The distance between the tip of the papillary muscle and the
plane of the mitral valve orifice also varies, with an average
of 22 ± 5 mm

21. THE CHORDAE TENDINEAE
THE CHORDAE TENDINEAE extend from the papillary
muscles to the leaflets . Three types can be described
depending upon their attachment on the leaflets
BASAL (OR TERTIARY) CHORDAE extend from the
papillary muscle or directly from the ventricular wall.
The basal chordae are attached to the base of the
posterior and commissural leaflets or to the annulus.
INTERMEDIARY (OR SECONDARY) CHORDAE extend
from the papillary muscles. The intermediary chordae
are attached to the ventricular side of the leaflets.
MARGINAL (OR PRIMARY) CHORDAE are attached to
the margin of the leaflets. The space between two
marginal chordae does not exceed 3 mm and their
attachment to the leaflet is often bifurcated or
trifurcated

24. FOUR ANATOMICAL STRUCTURES CLOSE TO THE ANNULUS ARE AT RISK
DURING SURGERY
• The circumflex artery runs
between the base of the left
atrial appendage and the
anterior commissure, 3 to 4 mm
from the leaflet attachment,
and then moves away from the
rest of the posterior annulus.
• The coronary sinus skirts the
attachment of the posterior
leaflet. It is initially in a lateral
position, and then crosses the
artery and becomes medial,
closerTo the posterior leaflet
attachment but 5 mm superior
to the annulus.
• The bundle of His is located
near the posteromedial trigone.

25. FOUR ANATOMICAL STRUCTURES CLOSE TO THE ANNULUS ARE AT RISK
DURING SURGERY
• The noncoronary and left
coronary aortic cusps are in
close relationship with the base
of the anterior leaflet
• .the nadir of these cusps is 6 to
10 mm away from the anterior
mitral valve annulus, a distance
that repre- sents a safety zone
for the placement of sutures in
this area provided that the
needle is properly oriented
towards the ventricle.

28. MITRAL VALVE REGURGITATION
• Type I: Mitral valve regurgitation with
normal leaflet motion.
• In type I mitral regurgitation, the course
of the leaflets between systole and
diastole has a normal amplitude and the
free edges of the two leaflets are well
positioned 5 to 10 mm below the plane
of the orifice.
• The regurgitation is due either to a lack
of coaptation between leaflets or to an
annular dilatation or a leaflet perforation,
tear, or vegetation

29. MITRAL VALVE REGURGITATION
• Type II: Mitral valve regurgitation with excess
leaflet motion: “leaflet prolapse.” Typically, a
leaflet prolapse is a valve dysfunction in which
the free edge of a leaflet overrides the plane of
the mitral valve orifice during systole.
• The resulting lack of leaflet apposition produces
a regurgitant jet, which runs obliquely over the
nonprolapsing leaflet.
• A mitral valve prolapse is due either to chordae
rupture or elongation or to papillary muscle
rupture or elon- gation

30. MITRAL VALVE REGURGITATION
• Type III: Restricted leaflet motion. In type III
mitral regurgitation , the motion of one or two
leaflets is limited primarily during diastole
(type IIIa) or during systole (type IIIb).
• Type IIIa is typically seen in rheumatic valve
disease.
• The valve motion is limited mostly during
diastole but also to some extent during systole
as a result of commissure fusion, chordae
thickening, and chordae fusion.
• Type IIIb mitral regurgitation displays a leaflet
tethering caused by papillary muscle
displacement resulting either from a localized
ventricular wall dyskinesia, as seen in ischemic
cardiomyopathy, or from a global dilatation of
the ventricle, as seen in end-stage
cardiomyopathy

31. • Another type III systolic dysfunction with a com- pletely different mechanism is
systolic anterior motion of the anterior leaflet (SAM) observed in obstructive
hypertrophic cardiomyopathy or in repaired Barlow’s disease. In these two settings
the motion of the anterior leaflet is first limited by the posterior leaflet and
inverted towards the left outflow tract

33. APPROACHES TO THE LEFT ATRIUM AND MITRAL VALVE
• TRADITIONAL APPROACH: VERTICAL LEFT ATRIOTOMY.

34. • The site of the vertical left atriotomy may be at the fatty interatrial junction or may be located
closer to the mitral valve by , separating the left atrium from the right, and allowing the
surgeon to perform left atriotomy 2 to 4 cm mediall.This latter incision requires closure where
the left atrium is thinner and may carry a greater risk of suture line bleeding.Accidental entry
in to the right atrium can allow air lock and obstruction of venous drainage. This is easily
controlled by oversewing the entry point.

35. TRANSECTION OF THE SVC also allows extension of the cephalad limb of the
atriotomy on to the superior roof and permits further rotation of the right atrium and atrial
septum to the left and away from the surgeon.The transection should leave at least a 1-to 2-cm
cuff on the right atrium and may require moving the SVC cannulation site from the right atrium to
the SVC or innominate vein.Air lock or compromised venous drainage may occur during this
transfer. SVC stenosis or thrombosis and sinoatrial node injury have been described with
this'technique.

36. TRANSSEPTAL APPROACH
(A) The vertical left atriotomy may also be converted to a transseptal approach if exposure is
inadequate. Begin by performing a vertical right atriotomy parallel to the left atriotmy .then,
open into the left atrium through the septum, with a transverse incision through the fossa ovalis,
perpendicular to the two atriotomies, and transecting the bridge of tissue between them.
(B) Alternatively, open into the left atrium through a vertical septal incision through the fossa
ovalis, parallel to the two atriotomies. With this incision, avoid encroaching on the coronary sinus
inferiorly or the dome of the left atrium superiorly. With either of these transseptal incisions,
avoid excessive medial displacement that may impinge on the mitral annulus

37. If exposure can be predicted to be difficult, as in the case of a small left atrium or deep chest, a
PLANNED TRANSSEPTAL APPROACH may be used.With a vertical right
atriotomy, parallel to the atrioventricular sulcus, make a secondary, vertical septal incision
through the fossa ovalis, avoiding the coronary sinus.

38. THE CLASSIC DUBOST APPROACH. Make a transverse right atriotomy and extend
it laterally into the superior pulmonary vein or between the pulmonary veins into the left atrium.
Then, beginning at the edge of the septa1 incision, carry the incision medially through the fossa
ovalis to expose the mitral valve

39. • SUPERIOR SEPTAL APPROACH-
The superior septal approach gives superb exposure.
Its liability is the possibility of atrial dysrhythmia.
Because this may be caused by disruption of the
sinoatrial node artery, Three variations of this arterial
supply
Pathway A, the most common (48% to 80%) courses
along the inner anterior border of the right atrium.
Pathway B courses anteriorly then behind the SVC to
the sino atrial (SA) node.
Pathway C arises from the circumflex and also
courses posteriorly over the left atrium, behind the
SVC to the SA node.

41. • THE SUPERIOR SEPTAL APPROACH. ’Begin by placing the SVC cannula lateral to the right
atrial appendage or in the SVC directly. Make a longitudinal (vertical) right atriotomy anterior to the
sulcus terminalis. Carry the incision cephalad around the superior base of the atrial appendage, or
directly through the appendage, to reach the atrial septum. Avoid the sino-atrial node, but keep the
incision 1to 2 cm from the right ventricle to allow safe closure. Incise the septum vertically through the
fossa ovalis, directly under and parallel to the right atriotomy, extending the incision superiorly to the
superior apex of the right atriotomy. Continue the confluence of these two incisions superiorly into the
dome of the left atrium. Retract the atrial septum gently to avoid atrioventricular nodal injury.

42. • THE SUPERIOR APPROACH TO THE MITRAL VALVE
• This approach allows adequate exposure of the mitral valve, with minimal to moderate
retraction of the aorta and SVC. It also allows a view of the mitral annulus more
perpendicular to its plane than do other approaches.
• Dissect the aorta and the SVC from the right pulmonary artery behind them. Avoid
injuring the left coronary artery behind the aorta. Mobilize the SVC from cephalad to the
right pulmonary artery inferiorly to the groove between the SVC and the right atrium
(sulcus terminalis). Incise the superior dome of the left atrium transversely as shown.
Avoid extending the incision too far to the left under the aortic root and into the thin-
walled left atrial appendage. Instead, provide greater exposure if necessary by extending
the incision to the right and into the right superior pulmonary vein.

43. TRANSAORTIC APPROACH
• transaortic approach-Perform a standard aortotomy. After excising the aortic leaflets, retract
the aortic root and annulus to expose the anterior leaflet of the mitral valve. Place the valve
sutures from the left atrium into the left ventricle and then through the mitral prosthetic
annulus from the superior to the inferior (ventricular) side, where the sutures are tied. The
prosthetic annulus thus lies below the native mitral annulus. Then proceed with the aortic
valve replacement.

44. LEFT VENTRICULAR APPROACH
• Concomitant mitral valve and left ventricular operations for ventricular septal defect or
aneurysm may both be performed through the ventriculotomy.
• Open the left ventricle parallel to the septum, through the scarred or infarcted tissue. Extend
the incision towards the apex to improve exposure without endangering the mitral
subvalvular apparatus. Either mitral valve repair or replacement may be performed through
this approach .With, mitral replacement, remove the prosthesis from the valve holder, which,
if used with this approach, may result in the valve being inserted upside down. Place the
valve sutures from the atrial side to the ventricular side and then through the prosthetic
annulus from its superior to inferior (ventricular) side.

45. RIGHT THORACOTOMY APPROACH.

46. LEFT THORACOTOMY APPROACH

47. AUTOTRANSPLANTATION

48. MINIMALLY INVASIVE APPROACHES

49. MINIMALLY INVASIVE APPROACHES

50. THANK YOU