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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. 24.8 Oval patch sewn on the right ventricular side of the interventricular septum, across the prosthetic ring
and upward along the aortotomy. A: A continuous suture line is reinforced with a strip of Teflon felt. B: An
alternate technique uses interrupted sutures buttressed with pledgets.
Maximizing the Enlargement
To maximize the left ventricular outflow tract enlargement, the Hemashield patch graft is sewn onto the right
ventricular side of the septum.
Interrupted valve sutures are inserted into the aortic annulus and through the patch at the level of the annulus
(see Chapter 5). After the sutures are inserted through the prosthetic sewing ring, the prosthesis is seated
satisfactorily into position (Fig. 24.8). The prosthesis can be sewn to the Hemashield with either continuous or
interrupted sutures.
Choice of Prosthesis
Because of their early calcification in children, stented tissue valves are not used. Low-profile disc or bileaflet
mechanical valves are the preferred prostheses if a pulmonary autograft is not available or contraindicated.
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Suture Line
A new continuous suture should be started at the valve sewing ring and should proceed so that the patch is laid
onto the aortotomy incision. Therefore, the septal suture line is tied snugly at the level of the prosthesis. This
entails separating the suture that closes the interventricular septum from the suture that closes the aortotomy
(Fig. 24.9).
FIG. 24.9 A continuous suture is used to attach the patch to the aortotomy opening.
A triangular, appropriately generous patch of Hemashield, bovine pericardium, or autologous pericardium is sewn
to the edges of the incision on the right ventricular outflow tract and across the first patch at the level of the
prosthetic valve (Fig. 24.10). Alternatively, a large pericardial patch is sewn onto the right ventricle and is
extended over the aortic patch to secure hemostasis.
Reinforcing the Suture Line
The suture line can be reinforced with Teflon felt if the right ventricular wall appears to be thin and friable.
Once the aortotomy closure is completed, the heart is filled and standard deairing maneuvers are carried out
(see Chapter 4).
Extended Aortic Root Replacement with an Aortic Homograft or Pulmonary Autograft
There are many problems associated with mechanical valves in infants and children. An alternative technique is
to combine the concept of aortic root replacement with reimplantation of the coronary arteries and the concept of
aortoventricular septoplasty. The aortic, right ventricular, and septal incisions are similar to those described
earlier for the Rastan-Konno procedure. The coronary arteries are excised with a generous cuff of aortic wall and
mobilized. The aortic valve and proximal ascending aorta are excised. If an aortic homograft is used, it is oriented
so that the attached anterior leaflet of the mitral valve can be used to patch the incision on the ventricular
septum. If a pulmonary autograft is used, a triangular piece of the right ventricular wall can be left attached to the
pulmonary valve annulus when harvesting the autograft. This muscle can then be used to patch the defect in the
interventricular septum. Aortic root replacement and reimplantation of the coronary ostia are completed as
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described in Chapter 5. The defect in the right ventricle is then closed with a piece of autologous or bovine
pericardium. The patch is sutured to the edges of the right ventriculotomy incision and along the annulus of the
valve of the homograft or autograft.
FIG. 24.10 Sewing a triangular patch to the edges of the right ventricular outflow tract opening and the aortic
root. Inset: Reinforcement of the suture line with Teflon felt.
Orientation of the Aortic Homograft
When the anterior mitral leaflet is left attached to the aortic homograft and used to patch the ventricular septal
defect, the homograft must be oriented in only one way. This may create complications for the reimplantation of
the coronary ostia. Alternatively, the mitral leaflet can be excised and the ventricular septum enlarged with a
triangular patch of Hemashield, which is then sewn to the annulus of the aortic homograft. If the anterior leaflet is
used to close the ventricular septal defect, sometimes the arc of the aortic homograft is 180 degrees from the
natural arc of the ascending aorta. In this situation, it is often helpful to divide the aortic homograft at the mid-
ascending aorta and
reverse the arc and reconnect with and end-to-end anastomosis (Fig. 24.11)
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FIG. 24.11 If the mitral skirt of a homograft is used to extend the hood of an aortic homograft in the pulmonary
outflow tract, it can sometimes make the graft angulated in the wrong direction for right ventricle to pulmonary
artery continuity. In this case, it can be helpful to turn the distal homograft 180 degrees.
Modified Rastan-Konno Procedure
When there is diffuse long-segment tunnel stenosis with a competent aortic valve and adequately sized
aortic annulus, a modified Rastan-Konno procedure is indicated.
Cardiopulmonary bypass with bicaval cannulation and aortic cross-clamping is used. An oblique incision is
made in the infundibulum of the right ventricle below the pulmonic valve (Fig. 24.6). This is extended to the
level of the aortic annulus just to the left of the right coronary ostium. A longitudinal incision is made in the
ventricular septum extending from just below the aortic annulus at the commissure between the left and
right coronary sinuses proximally on the septum past the area of obstruction. The thickened septal muscle
is resected from the left ventricular outflow tract. An oval patch of Hemashield is then used to close the
defect, placing horizontal, pledgeted, interrupted mattress sutures from the left ventricle through the septum
and then the patch on the right ventricular side (Fig. 24.12). The opening on the right ventricle is then
closed with a pericardial patch.
Aortic Valve Injury
Before making the septal incision, a small aortotomy to allow visualization of the aortic valve and annulus
may be useful. A right-angled clamp passed through the aortic valve can identify the appropriate location for
the septal incision. Alternatively, sometimes it is helpful to place a large needle from the left ventricular side
across the septum to the right ventricular side at the base of the aortic valve, which then marks the
superior-most extent of the Konno incision.
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FIG. 24.12 Modified Rastan-Konno procedure: septal incision and placement of horizontal mattress sutures
from the left ventricle to the right ventricle.
Injury to the Conduction System
The incision on the septum should be well to the left of the right coronary ostium to avoid the conduction
system.
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FIG. 24.13 Relief of supravalvular aortic stenosis. A: The shelf of fibrous tissue is excised. B: The aortic
root is enlarged by extension of the aortotomy into the noncoronary sinus of Valsalva. C: The defect is
covered with a large patch.
Inadequate Septal Opening
The incision on the ventricular septum must be extended far enough proximally to completely relieve the
narrowing of the left ventricular outflow tract.
SUPRAVALVULAR AORTIC STENOSIS
An oblique aortotomy provides good exposure. If the stenosis involves only the ascending aorta, it can be
conveniently managed by excising the fibrous ridge and sewing an appropriately sized, diamond-shaped
Hemashield or Gore-Tex patch across the stricture to relieve the stenosis (Fig. 24.13). The type of supravalvular
narrowing that is caused by a fibrous ridge usually extends onto the annulus and the commissures, however.
This fibrous ridge must be meticulously excised to free the aortic leaflets.
Patch Enlargement of the Ascending Aorta
The supravalvular lesion may be extensive and affect major parts of the ascending aorta. This lesion may require
extensive patch enlargement from the noncoronary sinus to the innominate artery. The width of the patch must
be oversized, with allowance made for somatic growth, to prevent the late recurrence of stenosis (Fig. 24.14).
Patients with William’s syndrome may have long-segment narrowing of the entire ascending aorta, necessitating
at times the replacement of the ascending aorta up to the innominate artery and possibly the aortic root as well.
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FIG. 24.14 Patch enlargement of the ascending aorta.
FIG. 24.15 Relief of an obstruction to the aortic sinuses. A: The aortotomy is extended down into the
noncoronary and right sinus of Valsalva. B: The fibrous shelf is removed. C and D: Pericardium is incorporated
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as a patch to enlarge both aortic sinuses and the ascending aorta.
Injury to the Aortic Leaflets
While the fibrous ridge is being excised, the aortic valve leaflets must be protected. Injury to the aortic leaflets
can produce aortic insufficiency.
Obstruction Extending into the Aortic Sinuses
At times, the fibrous ridge continues into, narrows, and distorts one or more of the aortic sinuses. After removing
the ridge, the involved sinuses of Valsalva may need to be enlarged with a patch of glutaraldehyde-treated
autologous pericardium or Hemashield to relieve the obstruction (Fig. 24.15).
Injury to the Left Coronary Artery Ostium
Removal of a fibrous ridge from the left coronary sinus region must be carried out carefully, always bearing in
mind the possibility of injuring the left coronary ostium.
The degree of supravalvular obstruction may be so severe that a more extensive form of therapy is indicated. An
effective procedure was devised by Brom with excellent results. In this technique, the aorta is completely
transected just above the stenotic segment (Fig. 24.16). The lumen of the stenosic area is rarely larger than 6 to
8 mm in diameter, as measured with a Hegar dilator; by a simple calculation, the circumference of the stenosis is
therefore approximately 18 mm, and the width of each segment between the commissures is 6 to 8 mm.
The aortic root, sinuses of Valsalva, and the coronary artery ostia are often dilated. A short, vertical incision is
made down into the noncoronary sinus to the level of maximal width of the proximal aorta (Fig. 24.17). This
improves exposure and allows close inspection of the lesion (Fig. 24.18). Similar incisions are made into the
other two coronary sinuses; the stenotic lumen is now fully opened (Fig. 24.19).
Incisions into the Coronary Sinuses
Incisions into the coronary sinuses should never extend beyond the point of maximal width of the proximal aortic
segment (Fig. 24.17). If these incisions are made deeper than this level, the patches will distort the base of the
valve and give rise to aortic incompetence.
FIG. 24.16 Transection of the aorta above the stenotic segment.
Distortion of the Coronary Ostia
To prevent distortion of the coronary ostia with subsequent patch plasty, the incisions into the coronary sinuses
should be to the right of the left coronary ostium and to the left of the right coronary ostium (Fig. 24.20).
Blood pressure control
Often patients with severe supravalvar aortic stenosis are “used” to much higher perfusion pressures of their
coronary arteries, given that these have been under substantial afterload. This is important to keep in mind when
weaning from cardiopulmonary bypass, so that the coronary arteries are not subject to relative hypotension (and
ischemia).
FIG. 24.17 Line of incision into the noncoronary sinus.
FIG. 24.18 Line of incision into the other two coronary sinuses.
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Obstruction of Left Main Coronary Ostium
Rarely, the fibrous tissue may involve the left ostium and the orifice may remain stenotic after excision of the
ridge. In these cases, the incision in the left sinus is carried onto the left main coronary artery and may be
continued to its bifurcation if necessary. This opening is then closed with a triangular patch of autologous
pericardium as described in the subsequent text to reconstruct the sinus and relieve the coronary stenosis.
The normal aortic valve annulus is measured with a Hegar dilator of appropriate size. The circumference of the
annulus is approximately three times its diameter or Hegar size. For example, if the aortic annular diameter
(Hegar size) is 24 mm, its circumference will be 24 mm × 3 or 72 mm. If the lumen of the stenotic segment is 6
mm (Hegar size), its circumference is 6 mm × 3 or 18 mm.
FIG. 24.19 Fully opened stenosis.
FIG. 24.20 Placement of incisions to prevent distortion of the ostia of the coronary arteries.
It is clear from these observations and calculations that the stenotic aortic segment must be enlarged by 54 mm
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