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Repair of Corrected Transposition Associated

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Repair of Corrected Transposition Associated
with Ventricular Septal Defect and Pulmonary Stenosis
Florentino J. Vargas, M.D.,* Guillermo 0. Kreutzer, M.D., Andres J. Schlichter, M.D.,
Miguel A. Granja, M.D., and Eduardo A. Kreutzer, M.D.
ABSTRAn Five patients with the diagnosis of classically
corrected transposition of the great arteries, ventricular
septal defect (VSD), and pulmonary outflow tract obstruction underwent surgical repair. A variant of a previously
described technique was used to avoid injury to conduction tissue. Through an incision into the anatomical left
ventricle, the VSD patch was sutured inferiorly to the right
and away from the edges of the defect and superiorlyto the
epicardial border of the ventriculotomy. The pulmonary
artery was opened, and its proximal end was closed with a
suture. A pouch containing the conduction tissue was
therefore obtained. Pulmonary ventriculoarterial continuity was reestablished using a valved or nonvalved Dam n or pericardial conduit. The postoperative course of
the patients was uneventful. No changes were demonstrated on comparison with preoperative cardiac rhythm.
Good hemodynamic performance was noted in 2 patients
in whom postoperative catheterizationwas performed.
Atrioventricular discordance is usually associated with
ventriculoarterialdiscordance. This combination is commonly called congenitally corrected transposition of the great
arteries (CTGA). Although CTGA may exist without
other intracardiac malformations, associated anomalies
are frequently present, including ventricular septal
defect (VSD), pulmonary outflow tract obstruction
(POTO), or anatomical tricuspid valve regurgitation [l51. When both VSD and POTO are present, surgical repair may present difficulties in that closure of the defect
and release of the subpulmonary obstruction carry the
risk of injury to the conduction tissue. A more detailed
knowledge of the anatomy and location of the His bundle led to the development of surgical techniques devoted to preserve its integrity. Satisfactory results have
already been achieved in the treatment of these combined anomalies [6-161.
Since 1978, we have successfully operated on 5 patients with CTGA, VSD, and POTO using a procedure
that is based on the same principle as that previously
described by Marcelletti and colleagues [12,13, 15, 161.
The VSD is closed such that both great arteries are
From the Division of Cardiovascular Surgery, Hospital de N3os and
Clinica Baztemca, Buenos Aires, Argentina.
Accepted for publication Feb 8, 1985.
Address reprint requests to Dr.F. J. Vargas, Clinica Baztemca, Juncal
3002, Buenos Aires 1425, Argentina.
‘Currently Graham Fellow of The American Association for Thoracic
Surgery at the Department of Cardiovascular Surgery, Children’s Hospital of Boston, Harvard Medical School, Boston, MA.
excluded from the venous ventricle. After closure of
the previously transected pulmonary artery, pulmonary
ventriculoarterialcontinuity is reestablished with a conduit. The tailoring of the patch, however, is carried out
in a different manner. Since the endocardial surface of
the anterior superior wall of the anatomical left ventricle
can be potentially dangerous because of the risk related
to the presence of conduction tissue in a subendocardial
location, we suture the patch superiorly to the border of
the ventriculotomy. A pouch of the systemic ventricle is
thereby created that contains the blind outflow of the
pulmonary ventricle and, thus, the area where the penetrating His bundle is located.
Patients and Methods
Three boys and two girls ranging in age from 2 to 7 years
were operated on at Children’s Hospital of Buenos Aires
from August, 1978, through July, 1982. The clinical impression of CTGA, VSD, and POTO was confirmed during a hemodynamic and angiocardiographicevaluation
in all of the patients. None had evidence of right atrioventricular valve regurgitation. The nature of the pulmonary ventricular outflow obstruction was subpulmonary
alone in 2, and combined subpulmonaryand valvular in 3.
In all patients, the temperature was lowered at operation to 25”C, and aortic crosstlamping was performed
under cold crystalloid potassium cardioplegia. After previous identification of the anterior papillary muscle
through the right atrium, an oblique ventriculotomywas
performed in between the overlying right coronary artery and the apex (Fig 1). The VSD and the subpulmonary area were exposed, and a Teflon patch was used to
exclude the VSD and the subpulmonary outflow tract
from the remaining chamber of the pulmonary ventricle.
A running suture that started 10 mm below the inferior
edge of the VSD was directed posteriorly to the superior
border of the ventriculotomy; in this way, a part of the
patch was attached to the base of the adjoining mitral
valve leaflet (see Fig 1). The sutures were placed anteriorly in the septum, away from the VSD, and were also
directed to the ventriculotomy. Finally, both the
superior edges of the ventriculotomyand the patch were
oversewn.
In the fvst 3 patients in the series, the pulmonary
artery was opened vertically and the pulmonary valve
leaflets sutured together from inside with a double running suture. In the last 2, the pulmonary artery was
transected and the proximal stump oversewn.
In the first patient we operated on, pulmonary ventriculoarterial continuity was reestablished with a 19mm nonvalved Dacron conduit. In the second patient,
an 18-mm xenograft valved conduit was used. A non-
510 The Annals of Thoracic Surgery Vol 40 No 5 November 1985
Fig 2. Patient 4. (A)Postoperative systemic ventriculogram showing
the systemic right ventricular chamber (SV)and the aorta (AO). Arrow points to a superiorly placed pouch thut connects with the SV.
( B ) Diagram of same structure shows a conduit interposed between
the pulmonary artery and the pulmonary zmtricle (W).The proximal stump of the pulmonary artery has been OveTSewn (S).
triculograms showed a sharply defined pouch in the apical part of the interventricular septum in continuity with
the systemic ventricular chamber (Fig 2).
Comment
Fig I. Repair of corrected transposition of the great arteries with mtricular septal defect (vsd) and pulmonary outflow tract obstruction
(POTO). (A)Incision of the anatomical left ventricle (dashed line)
is performed after previous identification of the mitral valve attachment through the right atrium. (B) The V S D is exposed through the
ventriculotomy. The suture ofthe patch (dashed line) stays to the
right and away from the border of the VSD. Through a vertical incision in the pulmonary artery, the free edges of the pulmonary valve
leaflets (pvl)are sutured together (in the last 2 patients, the pulmonary artery was transected and the proximal end closed with a suture). (C) A large [email protected] patch is attachedfrom 10 mm below the
V S D to the epicardial border of the mtriculotomy. I t must therefore
be sutured to the mitral valve leaflet (M)posteriorly and to the interventricular septum (away from the VSD) anteriorly. A pouch of the
systemic ventricle containing the POTO and the His bundle is
thereby obtained. (0)Pulmonary mtriculwrterial continuity is re-established by a conduit (COND). A 0 = aorta; PA = pulmonary artery.
valved pericardial conduit was employed in the remaining 3 patients, who were 2, 3, and 5 years old.
Postoperative recovery was uneventful, and all patients were discharged from the hospital in good hemodynamic condition. None had rhythm disturbances.
Results
Follow-up on the 5 patients ranges from 2 to 6 years, and
3 of them have been followed for more than 4 years. All
of them are in New York Heart Association Functional
Class I, free from symptoms and without medication.
Hemodynamic evaluation performed in 2 patients in
whom nonvalved conduits were placed showed Satisfactory cardiac performance, even though a pulmonary
ventriculoarterial gradient of 25 mm H g was present in 1
child. End-diastolic pressure in the anatomical left ventricle was within normal limits in both patients. Ven-
Avoidance of injury to the bundle of His represents the
main challenge in surgical management of CTGA, VSD,
and POTO. Despite the extensive literature on this topic
[7-161, a final conclusion cannot be made regarding the
exact location of the atrioventricular bundle as detected
at operation [ l l , 17, 181. Agreement exists, however,
that in situs solitus, the penetrating bundle merges into
the pulmonary ventricle somewhere in the area of pulmonary-mitral continuity to follow a subendocardial
course along the anterior wall of the ventricle, below the
pulmonary annulus [8, 91. It is therefore closely related
to the anterior and superior border of the VSD and embedded within the subpulmonary obstructive tissue. Attempts to directly relieve the subpulmonary obstruction
or to close the VSD by suturing the patch on the morphological left side of the septum carry a substantial risk
of surgically induced heart block [19]. Interposition of a
pulmonary ventriculoarterial conduit and placement of
the stitches on the morphologicid right side of the septum during closure of the septal defect [ll]constitute
the major advances in lowering the risk of damage to the
conduction tissue when treating these associated malformations.
An alternative technique has been suggested by Marcelletti and associates [16] at Mayo Clinic. They deviated
the patch from the lower edge of the defect to the endocardial surface of the anterior and superior wall of the
pulmonary ventricular outflow; both great arteries were
thereby connected with the systemic ventricle. After
closing the proximal transected pulmonary artery, they
reestablished pulmonary ventriculoarterial continuity
with a conduit. With this approach, the conduction system should stay to the left of the patch. Despite the
attractiveness of the technique, however, objections
511 Vargas et a1 Corrected Transposition with VSD and Pulmonary Stenosis
have been made mainly because of the potential risk
involved in placing sutures on the anterior and superior
wall of the outflow tract of the anatomical left ventricle
in the subpulmonary area, where the proximal part of
the penetrating His bundle is in a vulnerable subendocardial position [ll].
Using a rationale similar to the one just described, we
employed a somewhat different procedure in our 5 patients. In all of them, the patch was attached superiorly
to the epicardial border of the ventriculotomy, beyond
the subpulmonary, subendocardial area where the His
bundle is located. Since the patch goes from the lower
edge of the VSD to the epicardial border of the ventriculotomy, adequate exposure is obtained with no
need for retraction of the left ventricular outflow tract,
which remains hidden by the patch itself during the procedure. This minimizes the manipulation of and pressure trauma in the critical subpulmonary area.
A decision has to be made concerning the use of a
valved or a nonvalved conduit. A pericardial tube can be
easily placed without risk of compression, even in the
chest of a small infant. Also, no substantialdeposition of
fibrinous tissue is expected to develop in the inner surface of the tube. These are major advantages over a
valved Dacron tube [20, 211. The pulmonary regurgitation resulting from overloading an anatomical left ventricle will probably have little or no hemodynamic importance. Clinical or hemodynamic evidence of overloading
an anatomical left ventricle has not been demonstrated
in our patients. Nevertheless, the long-term follow-up
will ultimately show if the performance of these ventricles remains normal.
Use of a valved conduit may preclude such complications, but the patient will probably have to undergo
reoperation in the future for replacement of the prosthesis [19]. The long-term outcome of the xenograft and
homograft valved conduits seems to be deterioration of
the valve and progressive obstruction of the conduit by
fibrinous tissue [20-221.
Our experience, as reported in this article, has been
encouraging. In our small series, there has been no mortality or rhythm disturbances. In addition, the procedure
itself does not present technical difficulties. Therefore, it
seems valid to consider this technique as an alternative
for repair of CTGA with VSD and POTO. Closure of the
VSD by suturing the patch to the left aspect of the septum would be reserved for patients without POTO.
Addendum
Since submission of this article, 2 additional patients
were successfully operated on with the same technique.
An autologous pericardial valved conduit was used to
reestablish the pulmonary ventricle-pulmonary artery
continuity in both.
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