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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3683_Библиотеки_им_академика_М_И_Перельмана
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(72 to 18 mm) for it to match the size of the aortic valve annulus. Because this enlargement must be made among
the three commissures, each pericardial patch must be 54 mm/3, or 18-mm wide along its superior rim (Fig.
24.21).
Autologous, glutaraldehyde-treated pericardium is used to prepare triangular patches with specific
measurements; in this example, an isosceles triangle with a base of 18 mm and a height commensurate with the
distance between the stenotic segment and the maximal width of the proximal aorta (Fig. 24.21) is the necessary
size. The pericardial patches are then sewn in place with Prolene sutures (Fig. 24.21).
FIG. 24.21 An example of measurements needed for an accurate stenotic enlargement.
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FIG. 24.22 Completed repair of the stenosis.
The two aortic ends are now anastomosed in an end-to-end manner with a continuous Prolene suture in a
continuous suturing technique (Fig. 24.22).
Narrow Distal Aortic Segment
Occasionally, the lumen of the distal ascending aorta, just above the stenotic segment, may be small compared
with the newly constructed proximal aorta. This discrepancy can be rectified by further resection of the distal
aorta or a vertical incision into its lumen.
In select group of patients, it may be possible to perform end-to-end reconstruction of the aorta without the use of
pericardial patches. The distal aorta is anastomosed to the aortic root by making appropriate counterincisions to
provide three tongues of aortic tissue (Fig. 24.23).
Tension on the Anastomosis
The aorta must be well mobilized to provide adequate length, thereby minimizing any tension on the
anastomosis.
MANAGEMENT OF LEFT VENTRICULAR OUTFLOW TRACT OBSTRUCTION
ASSOCIATED WITH OTHER CARDIAC ANOMALIES
Interrupted Aortic Arch with Ventricular Septal Defect
Patients with interrupted aortic arch and ventricular septal defects often present with some form of left ventricular
outflow tract obstruction. This may be at the valvar level
with a bicuspid valve or small aortic annulus. The most common cause is posterior deviation of the conal septum.
FIG. 24.23 Completed repair of the end-to-end reconstruction of the aorta.
Patients with adequate annulus size, but with subaortic diameters less than 4 mm are candidates for incision or
resection of conal septal muscle before closure of the ventricular septal defect. Most frequently, this is
accomplished through a right atriotomy approach, performing a myotomy or myectomy of the conal septum
before securing the ventricular septal defect patch in place (see Chapter 21). A patch cut slightly smaller than the
defect is attached to the left side of the conal septum, thereby pulling the septum anteriorly and opening the
subaortic area.
Recurrent Obstruction
A significant number of patients undergoing surgery for this lesion require reoperation for left ventricular outflow
tract obstruction. This may be secondary to valvar issues, or the development of a subaortic membrane or
muscular narrowing. Therefore, these patients require close follow-up.
TRANSPOSITION OF THE GREAT ARTERIES WITH VENTRICULAR SEPTAL
DEFECT AND LEFT VENTRICULAR OUTFLOW TRACT OBSTRUCTION
The traditional surgical repair for transposition of the great arteries with ventricular septal defect and left
ventricular outflow tract obstruction has been a Rastelli procedure. This involves patching the ventricular septal
defect in such a way as to direct the left ventricular outflow to the aorta (in these cases to both great vessels)
and placing a conduit from the right ventricle to the main pulmonary artery. The long-term results of the Rastelli
procedure have been somewhat disappointing with late left ventricular dysfunction and sudden death. In
addition, patients with a restrictive or inlet ventricular septal defect or small right ventricle may not be candidates
for a Rastelli procedure. An alternate approach involves aortic translocation (“Nikaidoh” procedure), which
directly places the aorta over the left ventricle, eliminating the need for a large intracardiac prosthetic baffle.
Technique
Through a median sternotomy incision, cardiopulmonary bypass is achieved with distal aortic and bicaval
cannulation. The ductus arteriosus or ligamentum is doubly ligated and divided. After cooling to 28°C, the aorta
is cross-clamped and cardioplegia is administered into the aortic root. The aortic root is excised from the right
ventricular outflow tract, leaving a 5-mm rim of attached muscle below the annulus (Fig. 24.24A). This maneuver
is similar to the technique used to excise a pulmonary autograft (see Chapter 5). The pulmonary artery is
transected just above the valve and the pulmonic valve leaflets are excised. The pulmonary valve annulus and
conal septum are incised, carrying the incision into the ventricular septal defect (Fig. 24.24B). The continuity
between the pulmonic and mitral annuli is now apparent. The aortic root is slid posteriorly, without rotation, into
position over the left ventricle. The posterior half of the aortic root is anastomosed to the pulmonary annulus
using a running 5-0 or 6-0 Prolene suture (Fig. 24.25A). The ventricular septal defect patch is cut to the
appropriate size and shape and secured to the right ventricular side of the septum inferiorly and the anterior
portion of the aortic root superiorly (Fig. 24.25B). This may be accomplished with a running suture or interrupted
horizontal mattress sutures with pledgets.
Kinking of Coronary Arteries
The coronary arteries must be mobilized for a sufficient distance to prevent any distortion, tension, or kinking
when the aortic root is translocated. Some surgeons prefer to detach one or both coronary arteries as buttons
before moving the aortic root. After the aorta is secured in its new location, the coronary buttons can be
reattached to the same positions on the aortic root. Alternatively, the harvest sites can be patched with
autologous pericardium if it appears that reattachment at these locations will result in stretching or kinking of the
coronary arteries. New implantation sites on the aortic root are then identified, and openings, using care to not
injure the aortic valve leaflets. The anastomosis of the coronary button to the aorta
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is accomplished with a running Prolene suture. The techniques involved in mobilizing and reanastomosing the
coronary arteries are similar to those used during the arterial switch procedure (see Chapter 25). Coronary
reimplantation is particularly important if some aortic root rotation is required with positioning over the left
ventricular outflow tract.
FIG. 24.24 A: The aortic root has been excised from the right ventricle and the proximal pulmonary artery
divided. The dotted line shows location of conal septal incision. B: The pulmonary annulus is incised carrying
the incision through the conal septum into the ventricular septal defect.
FIG. 24.25 A: Attaching posterior half of aortic root to pulmonary annulus. B: Securing patch to ventricular septal
defect and anterior half of aortic root.
FIG. 24.26 The ascending aorta is divided to allow for a Lecompte maneuver to be performed.
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Aortic Insufficiency
The aortic root must be carefully sutured to the pulmonary annulus and the ventricular septal patch to prevent
valvar insufficiency. The anastomosis should maintain the geometry of the aortic annulus without distortion of
any of the leaflets. Care must be taken to not place sutures through the valve leaflets themselves.
The ascending aorta is transected, and a Lecompte maneuver is performed, bringing the pulmonary artery
anterior to the aorta (Fig. 24.26). The aortic root is reattached to the ascending aorta with a running 5-0 or 6-0
Prolene suture.
Mobilization of Right and Left Pulmonary Arteries
The right and left pulmonary arteries should be completely mobilized out to the pericardial reflection. The ductus
arteriosus or ligamentum also must be divided. This allows the pulmonary artery confluence to be positioned
anterior to the aorta without any traction, which may stretch and narrow the main and/or one or both pulmonary
arteries.
Length of Ascending Aorta
It is often necessary to resect a short segment of the ascending aorta before anastomosing it to the aortic root.
This prevents the aorta from bulging anteriorly when pressurized and compressing the posterior aspect of the
pulmonary confluence.
The aortic cross-clamp can be removed, and the right ventricular outflow tract reconstructed while rewarming is
completed. The main pulmonary artery is usually hypoplastic in these patients. To enlarge the main pulmonary
artery, a vertical incision is made anteriorly and extended to the confluence. If a homograft is not being used, the
right ventricular outflow tract can now be reconstructed. The posterior half of the main pulmonary artery is sewn
to the ventricular septal defect patch at the level of the aortic suture line (Fig. 24.27). A patch of glutaraldehyde-
treated autologous pericardium is then sutured to the remaining opening on the right ventricle inferiorly, and the
pulmonary artery superiorly, to complete the reconstruction. If the clinical scenario dictates (e.g., distance,
angulation, or physiology), use of a homograft or a bovine jugular conduit is similar to any right ventricular to
pulmonary artery conduit.
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FIG. 24.27 Posterior half of enlarged main pulmonary artery is sewn to the septal patch at the level of the aortic
suture line.
FIG. 24.28 In the Nikaidoh procedure, because the aortic root may be translocated inferiorly (with or without a
VSD patch), it can create an awkward “triangle” deficiency along the rightward most aspect of the right
ventriculotomy. To mitigate distortion of the proximal RV-PA conduit, it can be helpful to “close down” this area
with a prosthetic triangular-shaped patch (shown as small, but may be quite considerable in size).
Conduit from Right Ventricle to Pulmonary Artery
Alternatively, a pulmonary homograft may be interposed between the right ventricular opening and the enlarged
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main pulmonary artery (see Chapter 27). Again, the posterior aspect of the homograft must be carefully sewn to
the ventricular septal patch just at the aortic suture line to avoid injury to the aortic valve.
Injury to the Aortic Valve
When performing the posterior suture line connecting the main pulmonary artery to the right ventricular outflow
tract, care must be taken to not injure the aortic valve. By suturing on the septal patch material itself, just below
the aortic suture line, this complication should be avoided.
If using a conduit, sometimes the rightward aspect of the right ventriculotomy bordered by the translocated
root can be closed with a triangle-shaped prosthetic patch so as to facilitate the proximal right ventricular to
pulmonary artery conduit suture line (Fig. 24.28).
25
Transposition of the Great Vessels
Transposition of the great arteries is a congenital malformation in which the heart has atrioventricular
concordance and ventriculoarterial discordance. Therefore, the clinical findings are an anterior aorta that
originates from the morphologic right ventricle and a pulmonary artery that originates from the morphologic left
ventricle. Other congenital defects can also be associated with transposition of the great arteries.
Today, anatomic correction of transposition of the great arteries with or without ventricular septal defect is the
procedure of choice. When the interventricular septum is intact, the arterial switch operation must be performed
while the left ventricle is still prepared to handle systemic pressures. After 2 to 3 weeks of age, changes in the
left ventricular wall thickness and geometry may preclude a successful arterial switch procedure. If the left
ventricular pressure is less than 60% systemic, a two-staged approach involving initial pulmonary artery banding
with or without a systemic to pulmonary artery shunt followed by an arterial switch procedure when the left
ventricle becomes prepared is required. Alternatively, a so-called atrial switch procedure (Senning or Mustard
operation) may be undertaken.
The Senning and Mustard procedures were designed to achieve a rerouting of the venous returns in the two
atria; this entails channeling the systemic venous return from the caval veins into the left atrium, across the mitral
valve into the left ventricle, and through the pulmonary artery to the lungs. Similarly, pulmonary venous return
from the pulmonary veins is directed into the right atrium across the tricuspid valve into the right ventricle, which
functions as the systemic ventricle, pumping blood into the aorta. Except for the torn fossa ovalis, which is found
if a palliative balloon septostomy has been performed, the surgical anatomy of both the right and left atria is
essentially normal. The long-term follow-up of patients who have undergone a Senning and Mustard procedure
has shown a high incidence of atrial arrhythmias and a significant rate of late right ventricular dysfunction.
However, physiologic repair with one of these two procedures may be indicated in patients with transposition of
the great vessels and associated pulmonary valve stenosis, nonresectable left ventricular outflow tract
obstruction, or some abnormalities of the coronary arteries that may prohibitively increase the risk of anatomic
repair. An atrial switch procedure may be part of the surgical approach in patients with some complex congenital
heart lesions, and therefore every surgeon dealing with patients with congenital heart disease should have the
Senning and Mustard procedures as part of his or her surgical armamentarium.
SURGICAL ANATOMY
In hearts with transposition of the great arteries, the right ventricular wall thickness is greater than normal at birth
and increases progressively thereafter. If the ventricular septum is intact and no pulmonary stenosis exists, the
left ventricular wall thickness does not increase after birth, and within 2 to 3 months, the left ventricle is relatively
thin walled.
The aorta is most commonly directly anterior to the pulmonary artery, although occasionally, the great vessels
are side by side with the aorta to the right. The coronary arteries usually arise from the aortic sinuses facing the
pulmonary artery. Therefore, the nonfacing sinus is most often anterior. According to the Leiden convention,
sinus 1 is on the right-hand side and sinus 2 is the next sinus counterclockwise to sinus 1, as viewed from the
nonfacing, noncoronary sinus. Approximately 70% of patients have the left anterior descending and circumflex
coronary arteries arising as a single trunk from sinus 1 and a right coronary artery from sinus 2 (Fig. 25.1A). The
left anterior descending arises from sinus 1, and the right coronary artery and circumflex originate together from
sinus 2 in approximately 15% of cases (Fig. 25.1B). Rarely, all three main coronary arteries arise from a single
sinus, most commonly sinus 2. In some of these cases, the left anterior descending or left main coronary artery
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may be intramural.
Surgical Anatomy of the Right Atrium
Although the right atrium is morphologically molded into a single chamber, it is formed by two components: the
sinus venarum and the right atrial appendage (sometimes referred to as the body of the atrium). Systemic
venous return flows in from opposite directions through the superior and inferior venae cavae into the sinus
venarum. This smooth-walled area is the most posterior portion of the right atrium and stretches between the
orifices of the caval veins. From the viewpoint of the surgeon looking down into the right atrium, the sinus
venarum is more or less horizontal, with the superior vena
cava entering from the left and the inferior vena cava entering (bounded by the Eustachian valve) from the right
(Fig. 25.2).
FIG. 25.1 A-B: Coronary artery configuration (see text).
Just below and medial to the orifice of the superior vena cava arises the crista terminalis, a muscle bundle that
springs into prominence as it circles the orifice of the superior vena cava to the right lateral wall of the atrium and
continues inferiorly toward the inferior vena cava, thereby forming the boundary between the sinus venarum and
the atrial appendage. This muscle bundle is evidenced on the outside of the atrium by a groove, the sulcus
terminalis. Lying subepicardially in the sulcus terminalis, just below the entrance of the superior vena cava, is the
sinoatrial node, which may be vulnerable to injury from the various surgical incisions and cannulations that are
commonly performed on the right atrium. The remainder of the right atrium is made up of atrial appendage, which
begins at the crista terminalis and extends anteriorly (upward from the surgeon’s perspective) to surround the
tricuspid valve and form an expanded chamber.
In contrast to the smooth-walled sinus venarum, the lateral wall of the atrial appendage is ridged by multiple
narrow bands of muscle, the musculi pectinati. These bands arise from the crista terminalis and pass upward to
the most anterior part of the atrium. Functionally, they supply the right atrium with enough pumping capacity to
propel the venous inflow through the tricuspid valve into the right ventricle.
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