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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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FIG. 15.12 Technique for a diamond-shaped patch angioplasty.
Recoarctation
Recoarctation can occur as the aorta grows. For this reason, the diamond-shaped patch must be very wide,
resulting in a redundant, patulous bulge over the coarctation (Fig. 15.13). An aesthetically satisfactory patch
often results in recoarctation.
FIG. 15.13 Using an especially wide patch prevents recoarctation as the aorta grows.
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FIG. 15.14 A: The transected subclavian artery is opened medially across the roof of the aortic arch. B: The
subclavian flap is sutured in place, augmenting the hypoplastic segment.
REVERSED SUBCLAVIAN ANGIOPLASTY
Hypoplasia of the aortic arch between the left carotid and left subclavian arteries can be treated by a reversed
subclavian flap angioplasty. In patients with combined discrete coarctation and significant hypoplasia of the distal
arch, this technique can be combined with a standard coarctectomy. The distal arch must be mobilized, as well
as the origin of the left carotid artery and the portion of the arch just proximal to it. The left subclavian artery is
ligated as in the standard subclavian flap angioplasty. One vascular clamp is placed across the left carotid artery
and the aortic arch. The other clamp is placed on the descending aorta. The transected subclavian artery is
opened medially onto the aortic arch, across the roof of the distal arch, and onto the base of the left carotid
artery (Fig. 15.14A). The flap is then sutured in place with 6-0 or 7-0 Prolene sutures (Fig. 15.14B).
EXTENDED RESECTION AND ANASTOMOSIS
If the aortic arch is significantly hypoplastic, repair of the coarctation alone may result in an unacceptable
gradient. In these cases, extended resection with an anastomosis of the distal aorta to the undersurface of the
aortic arch should be carried out.
Extensive dissection and mobilization of the aorta from the origin of the innominate artery to the descending
thoracic aorta at the level of the third or even fourth intercostal artery are carried out. Ligation and division of the
ductus or ligamentum arteriosum facilitate the dissection. A curved vascular clamp is placed across the origin of
the left subclavian and left carotid arteries as well as the proximal aortic arch just beyond the innominate artery.
A straight clamp is placed across the descending aorta. The coarcted segment and ductal tissue are resected.
An incision is now made inferiorly on the aortic arch while a second matching incision is made on the lateral
aspect of the distal aorta (Fig. 15.15). The descending aorta is then anastomosed to the opening in the aortic
arch with a running suture Prolene. Some centers advocate for the use of continuous near-infrared spectrometry
(NIRS) cerebral monitoring throughout the case to confirm adequate cerebral bloodflow during the period of
cross-clamping.
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FIG. 15.15 Extended resection and anastomosis of the coarctation and hypoplastic arch. Note the improper
placement of the clamp (shaded) (shaded) the innominate artery.
Occluding Innominate Artery
The arch clamp must not occlude or compromise flow to the innominate artery (Fig. 15.15). Monitoring the
pressure in a right radial arterial line will allow this problem to be detected and quickly rectified.
Tension at the Anastomosis
Aggressive proximal and distal mobilization will avoid tension on the anastomosis; this will minimize the risk of
suture line bleeding and the subsequent development of stenosis.
Division of Intercostal Vessels
It may be necessary to ligate and divide one set of intercostal arteries in order to adequately mobilize the
descending aorta for a tension-free anastomosis. Sacrificing more intercostal vessels may increase the risk of
spinal cord injury.
ALTERNATE TECHNIQUES
Most patients with recoarctation can be successfully treated with balloon angioplasty with or without stent
placement. Balloon angioplasty is also an alternative to surgery for native coarctations in patients older than 3
months of age who have a discrete aortic narrowing.
Extraanatomic bypass grafts, such as those between the left subclavian and descending aorta or from the
ascending to the descending aorta, are rarely used now. Even the most complex recoarctations can be dealt with
directly using excision and an interposition graft or patching of the narrowed segment. If a left thoracotomy
approach is deemed to be inadvisable, a median sternotomy with the use of cardiopulmonary bypass and deep
hypothermia allows good exposure of the distal arch and proximal descending aorta (see Chapter 8).
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16
Pulmonary Artery Banding
Because most neonates undergo total correction for congenital heart defects, banding of the pulmonary artery is
only indicated for specific subgroups of patients. These include patients with multiple muscular ventriculoseptal
defects or ventriculoseptal defects complicated by other noncardiac congenital anomalies. Patients who present
after 4 to 6 weeks of age with simple transposition of the great arteries may require preliminary pulmonary artery
banding to prepare the left ventricle for an arterial switch procedure (see Chapter 25). Banding of the pulmonary
artery is also performed in some patients with univentricular hearts and pulmonary overcirculation (see Chapter
30).
INCISION
Most surgeons use a median sternotomy because it allows the anatomy to be evaluated more accurately. A left
thoracotomy incision is used in some patients, especially if the banding is performed in conjunction with the
repair of a coarctation.
TECHNIQUE
Through a median sternotomy, the pericardium is opened longitudinally after resecting the thymus. (Removing
the entire thymus in this surgery makes dissection at reoperation easier.) A patent ductus arteriosus, if present,
is first ligated (see Chapter 14). The main pulmonary artery is dissected free from the aorta and the origin of the
right pulmonary artery is identified. A band of Silastic 3- to 4-mm wide is placed around the proximal pulmonary
artery and tightened until the pressure distal to the band is approximately one-third systemic with an arterial
oxygen saturation no less than 75% on 50% inspired oxygen (Fig. 16.1). The constriction site on the band is
made permanent with stainless steel clips or interrupted sutures. The band is then secured to the adventitia of
the pulmonary artery at various intervals with interrupted 6-0 or 5-0 Prolene sutures (Fig. 16.1, inset).
Through a left thoracotomy, the pericardium is incised anterior and parallel to the phrenic nerve. The main
pulmonary artery is isolated, and the Silastic band is passed around it and narrowed as described previously.
Damage from the Band
The pulmonary artery may be tense and its wall thin and friable. Regular suture material or a narrow band may
cut through and produce hemorrhage that is difficult to control.
Difficulty Passing the Band around the Pulmonary Artery
It may be easier and safer to initially pass the tape around both the aorta and pulmonary artery through the
transverse sinus and then between the aorta and pulmonary artery.
Troublesome Bleeding
Small adventitial vessels on the aorta and pulmonary artery may give rise to troublesome bleeding; they must be
identified and cauterized.
Excessive Banding
The degree of banding must not be too constrictive because this will result in unacceptable cyanosis and
possible hemodynamic collapse.
Inadequate Banding
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Many times, the tightness of the band is limited by the hemodynamic response of the patient. Patients with
subaortic narrowing may not tolerate adequate constriction of the band. To limit the pulmonary blood flow in
these patients, ligation of the pulmonary artery or a Damus-Kaye-Stansel anastomosis and shunt procedure may
be required (see Chapter 30).
Early Reoperation to Adjust Band
It is not uncommon to leave the operating room with a suitable band, only to have the patient develop signs that
the band is too tight or too loose in the early postoperative period. In this case, reoperation may be required. If
the band is too loose, the patient may grow into it. The surgeon must weigh the risk of reoperation with that
of continued pulmonary overcirculation, possible pulmonary vascular disease, and failure to thrive.
FIG. 16.1 Technique for placement of a pulmonary artery band. The band is tightened with interrupted sutures.
Securing the band to the adventitia of the pulmonary artery (Inset).
Placing the Band Too Proximally
If the band is placed too proximally, the sinotubular ridge of the pulmonic valve will be distorted. To adequately
relieve the gradient during the debanding procedure, the sinus portion(s) of the pulmonary root often needs to be
patched. This may result in an incompetent pulmonic valve. This is especially problematic when an arterial
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switch or Damus-Kaye-Stansel procedure is planned at the second stage.
Band Migration
The band should be sewn to the adventitia of the proximal aspect of the main pulmonary artery (Fig. 16.1, inset).
This precaution prevents the band from migrating distally, narrowing the pulmonary artery at its bifurcation and
obstructing the right, left, or both branches.
After the optimal band constriction has been achieved, it is secured and the pericardium is approximated with
multiple interrupted sutures. The median sternotomy or thoracotomy is then closed in the usual manner.
If the procedure requires the use of concomitant cardiopulmonary bypass to repair other lesions (e.g., arch
reconstruction), the use of an internal pulmonary artery band is recommended, owing to the difficulty of properly
adjusting the band during the initial period immediately off bypass. In this procedure (Fig. 16.2), a small disc of
thin-walled Gore-Tex is used, whose diameter is that of the main pulmonary artery. A punch is taken from the
center of this disc, whose diameter is roughly the size of a shunt appropriate for the baby by weight. A
transverse, partial pulmonary arteriotomy is made halfway between the pulmonary root and the bifurcation, and
through this partial incision, the backwall of the Gore-Tex “washer” is sewn using a running Prolene. As this is
continued anteriorly, the Gore-Tex is included in between the two edges of the cut pulmonary artery. This
technique has the advantage of (1) a controlled source of pulmonary blood flow and (2) eliminating the possibility
of either band migration or pulmonary valve damage.
FIG. 16.2 Internal PA Band
ADJUSTABLE PULMONARY BAND DEVICE
An implantable device for pulmonary banding with telemetric control is currently available outside the United
States (Flow Watch, EndoArt S.A., Lausanne, Switzerland). This device is capable of repeated narrowing and
releasing of the pulmonary artery at the bedside, avoiding reoperation. Because of its elliptic shape, there
usually is no need for reconstruction of the pulmonary artery when the device is removed.
PULMONARY ARTERY DEBANDING
When total correction of the cardiac anomaly is undertaken, the pulmonary artery band must be removed. It may
be necessary to reconstruct the pulmonary artery to eliminate any gradient across the band site. When a Silastic
band has been in place for a short time, simple removal of the band often results in no gradient.
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FIG. 16.3 Technique for pulmonary artery debanding. A: Removal of the band. B: Incision and patch
enlargement of the pulmonary artery. C: Resection of the constricted segment and an end-to-end anastomosis of
the pulmonary artery.
Before the initiation of cardiopulmonary bypass, the band is dissected and removed (Fig. 16.3A). If a pressure
gradient or obvious deformity is noted at the band site, the pulmonary artery is repaired with the patient on
cardiopulmonary bypass. The pulmonary artery is incised longitudinally across the constricted segment. An
appropriately sized patch of glutaraldehyde-treated autologous pericardium or Gore-Tex is then sewn onto the
defect with a continuous 5-0 or 6-0 Prolene suture (Fig. 16.3B).
Persistence of the Gradient
Inadequate enlargement of the main pulmonary artery may be responsible for persistence of the gradient across
the site of the band.
Alternatively, the portion of the main pulmonary artery involved in the banding can be resected and an end-to-
end anastomosis performed between the proximal main pulmonary artery and the confluence of the right and left
pulmonary arteries (Fig. 16.3C).
Constriction of Anastomosis
All fibrotic tissue must be excised to prevent stenosis at the anastomotic site.
Pulmonary Valve Insufficiency
When the band has caused distortion of the sinotubular ridge, patching anteriorly into one sinus only often
causes valvular insufficiency. If the patient will not tolerate pulmonary valve incompetence, the pulmonary artery
can be transected and all three sinuses patched as described for supravalvular aortic stenosis (see Chapter 24).
Incorporation of the Band into the Pulmonary Artery
With the passage of time, the band may burrow through the wall of the pulmonary artery to become
subendothelial. The band can be divided anteriorly but left in situ and the pulmonary artery enlarged with a patch
angioplasty. Resection with an end-to-end anastomosis may also be used when this situation is encountered.
Occasionally, the band may migrate distally to the pulmonary artery bifurcation and cause distortion of its
branches. The incision on the pulmonary artery is then extended distally onto the left or both the left and right
pulmonary artery branches as needed. The defect is closed with a pericardial patch (Fig. 16.4).
Sizing the Patch
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The pericardial patch should be wide enough, particularly at its distal end, to prevent a residual gradient.
FIG. 16.4 Technique for patching pulmonary artery constriction at the bifurcation.
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17
Vascular Ring and Pulmonary Artery Sling
Persistence of both the right and left embryonic dorsal aortic arches results in the development of a double aortic
arch. The ascending aorta gives rise to right and left arches that encircle the trachea and esophagus and rejoin
to form the descending thoracic aorta. This acts as a ring and compresses the trachea and esophagus, causing
obstructive symptoms (Fig. 17.1). Each arch gives rise to a subclavian artery and a carotid artery. There is no
innominate artery in this condition. Surgery is indicated for symptoms related to narrowing of the esophagus
and/or trachea.
DOUBLE AORTIC ARCH
Incision
A left posterolateral thoracotomy in the fourth intercostal space is the approach most commonly preferred. A right
thoracotomy can be used if the left aortic arch is dominant, which occurs rarely.
Technique
The left lung is retracted anteriorly and inferiorly toward the diaphragm to bring into view the area of the aortic
arch and ductus arteriosus or ligamentum. The parietal pleura is incised longitudinally on the anterior surface of
the descending aorta and left subclavian artery. The pleural flap containing the vagus nerve and its branches is
retracted anteriorly; meticulous dissection is carried out to identify the local anatomy precisely. The surgeon
should be aware that pulling the nerve toward the pulmonary artery causes the recurrent nerve to lie along a
diagonal course behind the ductus or ligamentum, thereby increasing the risk of injury to the nerve.
The aorta and ductus or ligamentum are then mobilized by sharp dissection. The ductus or ligamentum is divided
after ligating both ends.
The smaller (usually left anterior) aortic arch is dissected free and divided between clamps. The ends are then
oversewn with 5-0 or 6-0 Prolene suture in two layers (Figs. 17.2 and 17.3).
Adhesions of the Esophagus and Trachea
Both the trachea and the esophagus must be dissected free of any adhesions and fibrous bands to ensure that
narrowing of these structures is relieved. This entails freeing up the divided ends of the arch from the
surrounding tissues.
Division of Ductus or Ligamentum
The ductus arteriosus or ligamentum must always be doubly ligated and divided. Otherwise, compression of the
trachea and esophagus will persist because of the aortic arch
being pulled downward toward the pulmonary artery. It is also important to resect any adjacent scar tissue that
could contribute to postoperative tethering or scar.
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FIG. 17.1 Double aortic arch.
FIG. 17.2 Exposure of the left anterior arch. Note ties around ligamentum arteriosum.
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