Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3654_Библиотеки_им_академика_М_И_Перельмана
.pdf
64
https://t.me/medicina_free
C. Frescura and G. Thiene
Table 5.1 Congenital anomalies of the mitral valve
Frequent forms
• Parachute mitral valve
• Arcade mitral valve
• Cleft of the anterior mitral leaet
• Double orice mitral valve
• Supravalvular mitral ring
• Ebstein anomaly of the mitral valve
Rare forms
• Mucoid dysplasia of the leaets
• Short/absent chordae tendineae
l- ventricular loop (corrected transposition of the great
arteries).
The short chordae tendineae (Fig.5.9) impair the mobility of the mitral valve leaets and interfere with the closure
of the valve, causing valvular insufciency.
Incompetence of the mitral valve is also present when the
chordae tendineae are absent (Fig.5.10).
Elongated chordae tendineae with redundant and prolapsing leaets (mitral valve prolapse) are rarely present in
infancy and children.
ab c
Fig. 5.1 Parachute mitral valve. (a) Drawing of a parachute mitral
valve: all the chordae tendineae to the mitral leaets originate from a
single papillary muscle. The valve is stenotic with a parachute appearance. (b) View of the left cardiac chambers: the chordae tendineae of
both the mitral leaets are attached to the posteromedial papillary muscle. The mitral valve takes the shape of a parachute. The anterior papillary muscle is hypoplastic. (c) External view of the same specimen:
note an aortic isthmic coarctation with a patent ductus arteriosus
5 Congenital Anomalies oftheCardiac Valves
https://t.me/medicina_free
65
Fig. 5.2 Mitral arcade. (a)
Drawing of the
muscularization of the mitral
leaets. The abnormal
differentiation of the chordae
tendineae gives an “arcadelike” appearance to the valve.
(b) View of the left cardiac
chambers: the mitral valve is
dysplastic with
muscularization of the
chordae tendineae and of the
free margin of the leaets.
The interchordal spaces are
absent. The valve looks like
rheumatic
Fig. 5.3 Isolated cleft of the
mitral valve. (a) Drawing of a
mitral cleft, which consists of
a “V-shaped” incision in the
anterior mitral leaet. The
apex of the incision points to
anulus. The cleft is the cause
of mitral valve insufciency.
(b) Anatomical view of the
left cardiac chambers. The
arrow indicates the cleft in the
anterior mitral leaet. Note
the deep incision reaching the
anulus and the presence of
chordae tendineae anchoring
the two parts of the anterior
leaet to the ventricular
septum
ab
ab
66
https://t.me/medicina_free
C. Frescura and G. Thiene
Fig. 5.4 Mitral cleft with ostium
primum defect. A mitral cleft is
part of partial atrioventricular
septal defect, a malformation
characterized by an ostium
primum atrial septal defect,
mitral cleft, and insufciency of
the mitral valve. (a) View of the
left cardiac chambers: a large
atrial septal defect is present at
the atrioventricular junction.
Note the mitral cleft (arrow). (b)
View from the right ventricle:
note the large ostium primum
septal defect. A patent foramen
ovale is also present (arrow)
Fig. 5.5 Double orice
mitral valve. (a) Drawing of a
mitral valve with double
orice. The double orice is
due to the partial fusion of the
anterior and posterior leaets
that determine the formation
of a brous bridge (“bridgetype” double orice). (b)
Anatomical view of the left
cardiac chambers: a
“bridge-type” double orice
is present, associated with a
cleft of the anterior mitral
leaet
ab
ab
Fig. 5.6 Double orice
mitral valve. The “hole-type”
double orice is characterized
by a hole within one of the
mitral leaets. (a) Anatomical
specimen with an accessory
mitral orice in the anterior
mitral leaet. The orice
shows a tensor apparatus. (b)
Closeup of the same specimen
that evidences the
morphology of the “holetype” double orice
ab
5 Congenital Anomalies oftheCardiac Valves
https://t.me/medicina_free
a
67
bc
Fig. 5.7 Supravalvular mitral ring. (a) Drawing of supravalvular mitral
ring which consists of a brous diaphragm with a central orice located
in the left atrium, over the mitral valve (arrows). The mitral valve may
be normal or the leaets may be distorted and fused with the brous
diaphragm. (b) View from the enlarged left atrium: the mitral valve is
not recognizable due to the presence of a circumferential brous diaphragm with a restrictive orice. (c) View from the left ventricle: the
mitral valve is small with short chordae tendineae and small interchordal spaces. A perimembranous ventricular septal defect is present
(arrow)
68
https://t.me/medicina_free
C. Frescura and G. Thiene
Fig. 5.9 Mitral valve with short chordae tendineae. The mitral leaets
are normal while the chordae tendineae are short and few, thus impairing the leaet motion and causing incompetence
Fig. 5.8 Valvular mitral ring. View of left atrium and ventricle: note a
ridge within the anterior mitral leaet. The morphology of the mitral
valve is distorted with dysplastic leaets and short chordae tendineae
ab
5 Congenital Anomalies oftheCardiac Valves
https://t.me/medicina_free
Fig. 5.10 Mitral valve with
absent chordae tendineae and
severe incompetence. (a)
View from the left atrium of
the incomplete mitral valve.
The surgically repair of the
mitral valve failed. Note the
enlarged left atrium. (b)
Outow tract of the left
ventricle: the mitral leaets
show the absence of chordae
tendineae, cause of valve
insufciency. A small
perimembranous ventricular
septal defect is also present
(arrow)
69
Tricuspid Valve
(“auricularization of the right ventricle”). The displaced leaflets are usually dysplastic. Sometimes the leaets are rmly
Congenital malformations of the tricuspid valve, such as
focal or diffuse thickening of the valve leaets, decient
development of chordae tendineae and papillary muscles,
adherence of valve leaets to the ventricular wall, and focal
agenesis of valvular tissue are collectively termed as “tricuspid valve dysplasia.”
The most important morbid entity within the spectrum of
tricuspid dysplasia is represented by the Ebstein anomaly.
In this congenital cardiac malformation, the septal and
sometimes the posterior leaets of the tricuspid valve do not
attach normally the valvular annulus, being adherent to the
musculature of the right ventricle (Figs. 5.11 and 5.12).
Therefore, the effective tricuspid orice is displaced downward into the right ventricular cavity, at the junction of the
inlet and apical trabecular components. The point of maximum displacement is located at the commissure between the
septal and posterior leaets. The anterior leaet usually is
not involved in the process of apical displacement. The
degree of displacement of the leaets may vary from cases
with minimal displacement to cases where the entire inlet
portion of the right ventricle becomes part of the right atrium
adherent to the right ventricular wall.
The displaced tricuspid valve divides the right ventricle
in two portions: one, the inlet portion, is functionally integrated in the right atrium (“atrialized ventricle”), and the
other, comprising the trabecular and outlet portions, constitutes the functional hypoplastic right ventricle. The atrialized portion of the right ventricle presents a thin and brotic
parietal wall, sometimes missing myocardial tissue, with
pronounced dilatation. The right atrium and the right atrial
appendage are dilated.
Ebstein anomaly of the tricuspid valve can appear single
or in association with other cardiac malformations. Usually
an atrial septal defect, fossa ovalis type, or a patent foramen
ovale is present accounting for a right-to-left shunt. In addition, more severe malformations can be associated, such as
pulmonary atresia with intact ventricular septum.
In some cases of Ebstein anomaly, the presence of accessory atrioventricular connections, located in the septum or in
the lateral part of the right atrioventricular sulcus, does exist
as a substrate of reentry arrhythmias in the setting of ventricular preexcitation (Wolff-Parkinson-White syndrome).
70
ab
ab
https://t.me/medicina_free
C. Frescura and G. Thiene
Fig. 5.11 Ebstein anomaly of the tricuspid valve. (a) Drawing of the
Ebstein anomaly of the tricuspid valve: the septal and posterior leaets
of the tricuspid valve are displaced toward the apex of right ventricle.
The right ventricle is reduced in size and the atrium is abnormally
enlarged, including the atrialized portion of the right ventricle. A fossa
Fig. 5.12 Ebstein anomaly
of the tricuspid valve. (a)
View of the right ventricle. A
prosthetic valve is inserted at
the atrioventricular junction.
The tricuspid leaets are
displaced into the right
ventricle. The right ventricle
is dilated with a thin wall. (b)
Closeup of the same specimen
showing the displacement of
the tricuspid leaets
Common Atrioventricular Valve
ovalis-type interatrial septal defect is present with a right to left shunt
(arrow). (b) Anatomical view of the right cardiac chambers: note the
enlarged right atrium and the abnormal insertion of the anterior and
posterior tricuspid leaets down into the right ventricle. Note the atrialized portion of the right ventricle
by Rastelli etal. in three different types according to the morphology of the anterior leaet of the common atrioventricular
During the embryological life, the common atrioventricular
valve does not differentiate in two separated valves and orices (tricuspid and mitral). The postnatal persistence of the
common valve is usually associated with a huge septal defect
in the atrioventricular region (Fig.5.13) with both interatrial
and interventricular communication. This anatomical complex, known as complete atrioventricular canal, was classied
valve. The type A is characterized by a subdivided anterior
leaet with chordal insertions to the crest of ventricular septum (Fig.5.14). In type C the common anterior leaet is not
subdivided and is overriding the ventricular septum (Fig.5.15).
Type B is rare and the common anterior leaet attached to an
abnormal papillary muscle of the right ventricle (Fig.5.16),
without chordal insertion to the ventricular septum.
5 Congenital Anomalies oftheCardiac Valves
https://t.me/medicina_free
a b
71
Fig. 5.13 Common atrioventricular valve. (a) Schematic representa-
tion of the common valve and atrioventricular septal defect. The presence of a common atrioventricular valve in association with an
atrioventricular septal defect constitutes the so-called complete atrioventricular defect (also known as complete atrioventricular canal). (b)
ab
Fig. 5.14 Common atrioventricular valve, type A. (a) View of the left
outow tract: a common atrioventricular valve is present with insertion
of chordae tendineae on the crest of the ventricular septum. Note the
large atrioventricular septal defect. (b) View from the right cardiac
View from the right cardiac chambers: a large atrioventricular septal
defect is present in association with a common atrioventricular valve
showing chordal insertion to the crest of the ventricular septum (complete atrioventricular canal type A of Rastelli classication)
chambers of the same specimen: a large atrioventricular septal defect is
associated with a fossa ovalis defect (arrow). Note the common atrioventricular valve with chordal insertion to the crest of the ventricular
septum
Fig. 5.15 Common
atrioventricular valve, type C.
(a) View from the right
atrium: the anterior leaet of
the common atrioventricular
valve is overriding the
interventricular septum,
without chordal insertions. (b)
View of the left outow of the
same specimen showing a
large atrioventricular septal
defect and a common
atrioventricular valve without
chordal insertion to the crest
of the ventricular septum
ab
72
ab
https://t.me/medicina_free
Fig. 5.16 Common
atrioventricular valve, type B.
(a) View from the right
cardiac chambers: an
atrioventricular septal defect
is associated with a common
atrioventricular valve without
chordal insertion to the crest
of the ventricular septum. (b)
View of the right ventricular
outow: the anterior leaet of
the common atrioventricular
valve is attached to an
abnormal papillary muscle of
the right ventricle (complete
atrioventricular canal)
C. Frescura and G. Thiene
Anomalies oftheSemilunar Valves
Aortic Valve
The stenosis of the aortic valve may manifest in infancy with
a dysplastic tricuspid, bicuspid, or unicuspid shape
(Table5.2).
Table 5.2 Malformations of the aortic valve
• Unicuspid aortic valve
− Unicommissural
− Acommissural
• Bicuspid aortic valve
• Tricuspid myxoid aortic valve
• Quadricuspid aortic valve
In the congenital tricuspid aortic valve stenosis, the three
cusps present nodular myxoid dysplasia, and endocardial
broelastosis may be associated (Fig.5.17).
The unicuspid aortic valve is the most severe type of congenital aortic stenosis. The unicuspid aortic valve may be
unicommissural or acommisuural (Table5.2). The unicommissural aortic valve shows a single leaet with a single
commissure and an eccentric orice (Fig.5.18). In the acommissural valve, distinct cusps did not develop and only short
raphes are identiable in the site of failed division of the
cusps (Fig.5.19). In unicuspid valve, the anulus is hypoplastic and the ascending aorta shows a reduced diameter. The
concomitant presence of hypoplastic left ventricle or
endocardial broelastosis (Fig.5.20) aggravates the clinical
presentation.
The bicuspid aortic valve is the most frequent congenital
heart disease, with a prevalence in the autopsy studies of
general population varying from 0.5 to 1.2%.
Isolated bicuspid aortic valve may be silent until adulthood, the presence of a bicuspid aortic valve being revealed
at the onset of complications along the natural history.
The anatomical characteristic of bicuspid aortic valve is
the presence of two cusps (Figs.5.21 and 5.22). Usually, a
raphe is located in one of the two sinuses of Valsalva and
most probably derived by an “aborted” commissure
(Figs.5.22 and 5.23). Under the raphe, there is no interleaet
triangle. Cases of bicuspid valve without raphe are rare
(Fig.5.21).
The aortic cusps may be in anteroposterior or laterolateral
position (Fig.5.24). When the cusps are in anteroposterior
position, a raphe is present in the anterior sinus, due to
embryonic fusion of anterior right and left cushions. In this
setting, both the coronary arteries originate from the anterior
sinus (Figs. 5.25 and 5.27). When the cusps are placed in
laterolateral position, the raphe is located in the left sinus and
results from the fusion of right and posterior cushions. The
coronary arteries originate each from the opposite sinus
(Fig.5.26). The anteroposterior position of the cusps is the
more frequent occurrence, accounting for 70% of cases.
The bicuspid aortic valve may be an isolated malformation or may be associated with other congenital heart dis-
5 Congenital Anomalies oftheCardiac Valves
https://t.me/medicina_free
73
Fig. 5.17 Tricuspid stenotic
and dysplastic aortic valve.
(a) Schematic representation
of a stenotic tricuspid aortic
valve with dysplastic myxoid
degeneration of the cusps. (b)
Corresponding anatomical
specimen: note the thickened
cusps with nodular myxoid
excrescences. The left
ventricle is hypertrophic with
endocardial broelastosis
Fig. 5.18 Unicuspid,
unicommissural aortic valve.
(a) Drawing of unicuspid and
unicommissural aortic valve:
only one aortic cusp and a
single commissure are
present. The orice is
eccentric and usually left
posterior. (b) Anatomical
specimen with an aortic valve
with a single dysplastic cusp
and commissure with myxoid
nodular excrescences
ab
ab
eases like ventricular septal defect and/or aortic arch
coarctation (Figs.5.27, 5.28 and 5.29).
Familial reurrence of bicuspid aortic valve happens in
approximately 9% of cases. Inheritance is consistent with an
autosomal dominant pattern with reduced penetrance.
Echocardiographic screening is recommended for rstdegree relatives of patients with bicuspid aortic valve.
A role of neural crest in the development of bicuspid aortic valve has been postulated, because of the frequent association with isthmic coarctation.
In young age a bicuspid aortic valve may remain asymptomatic, but, with time, the malformation is prone to multiple
complications. The natural history of bicuspid valve is
indeed characterized by progressive calcication of the cusps
Соседние файлы в папке Библиотека им академика М.И. Перельмана