) because total circulatory arrest is almost never used. The two cavae are selectively can- nulated, and this allows work within the heart to progress during cooling and rewarming.

Repair of ventricular septal defects (VSD) is performed with cardiopulmonary bypass and moderate hypothermia, aortic cross-clamping with cardioplegia, and profound local cardiac cooling. In small infants with associated complex anom- alies, maximal exposure may be gained with cardiopulmonary bypass, deep hypothermia, and low-flow cerebral perfusion (about 0.25-0.5 L/min/m

) because total circulatory arrest is almost never used. The two cavae are selectively can- nulated, and this allows work within the heart to progress during cooling and rewarming.

Most ventricular septal defects are repaired by working through a right atri- otomy. If exposure of a subpulmonary VSD is not ideal through this approach, a small transverse right ventriculotomy placed immediately below the pulmonary valve annulus is used or the defect is closed working through the proximal main pulmonary artery or, rarely, the ascending aorta. An apical VSD may be closed through a small, low right ventriculotomy, while multiple muscular VSDs may rarely require an apical left ventriculotomy.

Most defects are closed with interrupted pledgeted mattress stitches and a knitted Dacron® patch. Knitted Dacron® is preferred because it facilitates tissue ingrowth and early complete endothelialization of the patch. Only the smallest VSDs are closed primarily without a patch. A running stitch technique is used rarely, in contradistinction to infants who undergo total repair of truncus arte- riosus; because the right ventriculotomy exposure allows this technique to be used with facility. It is mandatory to tie stitches in the ventricular septum with the heart arrested and relaxed. Otherwise, there is a risk of tearing of septal muscle as stitches are tied. With complex low muscular VSD's the sandwich patch technique can be used avoiding placement of stitches in septal tissue.

5-1. Perimembranous Ventricular Septal Defect

I prefer the transatrial approach to repair membranous VSD. There is usually

excellent exposure of the entire defect, especially along the inferior and poste-

rior rims, where conductive tissue is located.

FIGURE 5-1. The child has been

placed on cardiopulmonary bypass and systemically cooled.

The aorta is clamped and car- dioplegia solution is infused. A right atriotomy is made, and the perimembranous VSD is ex- posed by retracting the tricuspid valve leaflets. To stabilize the exposure, stay sutures are placed in the atrial wall at the atriotomy and in the anterior and septal leaflets of the tricuspid valve.

anterior tricuspid valve leaflet

ventricular septal defect

septal tricuspid valve leaflet

ceph

A

R < > L caud

ceph R < -

caud

anterior tricuspid valve leaflet attached to posterior rim of VSD

ventricular septal defect

septal leaflet of tricuspid valve

FIGURE 5-2. Multiple interrupted multifilament mattress sutures with Teflon® felt pled- gets are placed around the rim of the ventricular septal defect. When the septal tricuspid valve leaflet is attached to the margin of the VSD along the posterior and inferior rim of the defect, sutures are passed through the base of this leaflet to avoid conductive tissue.

If there is no septal leaf attachment here, sutures are placed superficially and directly in the rim of the VSD rather than in septal tissue remote from the VSD rim. More anteri- orly, along the inferior margin of the VSD, stitches are placed near the margin of the VSD in muscular septum. Generally, these stitches are placed through 25% of the thickness of the septum. Along the anterior margin of the VSD, stitches are placed in about 50% of the thickness of the septum on the right ventricular surface. Stitches along the cephalad rim of the ventricular septal defect are placed similarly, or they can be placed in the base of the anterior tricuspid valve leaflet when the latter is attached to this rim of the VSD.

Care must be exercised to avoid injury to aortic valve cusps that are located in this area.

The posterior margin of the VSD is usually in continuity with the base of the anterior tri-

cuspid valve leaflet. Stitches here are passed through the base of this leaflet near the

annulus.

ceph

R^-

caud

fibrous remnant of membranous septum in posterior inferior corner

FIGURE 5-3. In some patients a fibrous remnant of the membranous septum is present in the posterior inferior corner of the VSD. When present, the corner stitch is placed in this remnant that is adjacent to but separate from the His' bundle.

ceph R < -

caud

anterior tricuspid valve leaflet attached to VSD posterior rim

FIGURE 5-4. The anterior tricuspid valve leaflet is attached to the posterior rim of the VSD.

A small probe can identify the base of the leaflet near the annulus to identify the precise

location for placement of the stitches.

R ^

aortic valve cusp adjacent to cephalad margin of VSD

FIGURE 5-5. The cephalad margin of the VSD is adjacent to the aortic valve. The aortic valve annulus is identified so that stitches can be placed in this structure or in adjacent right ventricular muscle and avoid damage to the aortic valve cusps. To identify the cusps, the aortic valve is observed in the closed position while cardioplegia solution is infused in the aortic root.

ceph R < -

caud

anterior leaflet

septal leaflet

FIGURE 5-6. Stitches have been placed circumferentially in the rim of the VSD.

ceph R < -

caud

VSD patch

FIGURE 5-7. Stitches are placed in a knitted Dacron® patch which is cut to conform to the size and shape of the VSD.

ceph R < -

caud

Dacron patch

FIGURE 5-8. Repair stitches placed in a Dacron® patch are tied. The integrity of the closure is checked with a 1-mm probe that is used to gently probe beneath the patch.

Residual openings can usually be found and closed at this point in the operation.

FIGURE 5-9. In another patient

who was re-explored 7 years after VSD repair, the totally endothelialized patch is invisi- ble beneath endocardial tissue, as seen through a right atriotomy.

endothelialized patch

5-2. Subpulmonary Ventricular Septal Defect

Subpulmonary ventricular septal defects are located high in the ventricular septum and immediately below the pulmonary valve. Myocardial relaxation with cardioplegic arrest allows the upper septum to be retracted inferiorly, so that many subpulmonary defects can be closed completely through the transatrial approach. In many cases, an aortic valve cusp is intimate with the rim of this ven- tricular defect and care must be used to avoid damage to the valve. If exposure through the atrium is not satisfactory, this approach should be aborted and a high small transverse right ventriculotomy or proximal main pulmonary arteriotomy used for the repair. Working through the proximal ascending aorta with retrac- tion of the aortic valve is an alternative repair exposure.

FIGURE 5-10. The supracristal

subpulmonary VSD is seen immediately below the pul- monary valve by looking through a right atriotomy while retracting the anterior tricuspid valve leaflet.

subpulmonary ventricular septal defect

membranous

ventricular

septum

ceph A

R^-

caud

ventricular septal defect

FIGURE 5-11. With retraction, the upper ventricular septum is shifted caudad for satisfac- tory exposure of the VSD, which was closed through this approach.

ceph R < -

caud

main pulmonary artery

pulmonary valve leaflet

ventricular septal defect

FIGURE 5-12. In another patient, exposure of the VSD is through a proximal transverse

main pulmonary arterotomy with retraction of pulmonary valve leaflets.

ceph R < -

caud

pulmonary valve leaflet

aortic valve leaflet

FIGURE 5-13. With the aortic valve in the closed position during delivery of cardioplegia, an aortic cusp fills most of the VSD. Without repair, the resulting stretching and disten- tion of the cusp may lead to aortic insufficiency. Felted mattress stitches are placed around the rim of the VSD for the repair. Because there is a common annulus between the aortic and pulmonary valves, stitches at the cephalad rim of the VSD are placed at the base of a pulmonary valve leaflet through the common semilunar valve annulus without felt pledgets.

ceph R < - - ^ L

caud

pulmonary valve leaflet

VSD patch

FIGURE 5-14. Stitches are placed in a Dacron® patch and then tied for repair of the defect.

Along the cephalad rim, stitches are placed in the valve annulus so there should be little

distortion of the pulmonary valve leaflet.

ceph R < - - • L

caud

pulmonary valve annulus

ventricular septal defect

FIGURE 5-15. In another patient, the subpulmonary VSD is exposed through a high right ventriculotomy. A dilated and prolapsing aortic valve cusp is present in the upper part of the VSD; this resulted in aortic insufficiency. The VSD is adjacent to the pulmonary valve annulus.

ceph R ^ - - > L

caud

FIGURE 5-16. The aortic valve is in the closed position with distention of the aortic root

during cardioplegia solution infusion. The distended aortic valve cusp fills much of the

VSD, and one can appreciate the mechanism by which aortic insufficiency develops in

children with this anomaly. This child underwent concomitant aortic valvuloplasty.

caud L < -

ceph

stretched and insufficient right coronary cusp

non coronary cusp

left coronary cusp

FIGURE 5-17. The proximal ascending aorta has been opened. The aortic valve is trileafed with normal left coronary and noncoronary cusps. A blunt sucker tip is placed in the sinus of Valsalva of the right coronary cusp, demonstrating the stretched and prolapsed cusp which allows aortic insufficiency.

caud L<«-

ceph

redundancy in right leaflet

marking stitch in corpora arantii

FIGURE 5-18. A marking stitch is passed through the corpora arantii of the left and non-

coronary cusps. The free margin of the right coronary cusp is pulled toward the right-left

cusp commissure to exclude redundancy in the cusp. The marking stitch is passed through

the region of the right cusp adjacent to the other two corpora arantii. A second stitch is

placed in the right-left cusp commissure, imbricating the redundant right cusp. The right

coronary cusp is now supported and should not be insufficient.

caud L « -

ceph

two mattress stitches in redundant cusp

competent right coronary cusp

felted stitch on top of new commissure

FIGURE 5-19. Two pledgeted mattress sutures are passed through the redundant right cusp tissue and through the aortic wall, firmly pressing the redundant tissue against the aortic wall. A third pledgeted mattress suture is placed over the top of the new right-left com- missure. One arm of this mattress stitch passes through the right and left cusps, respec- tively, at the commissure. The other arm of the stitch passes to the child's left, through the full thickness of the aorta in the right cusp sinus of Valsalva at the commissure. It is passed through a second felt pledget and then from outside to within the aorta in the left cusp sinus of Valsalva at the commissure. Both arms of this stitch are then passed through the end of the original felt pledget that is used in the mattress suture. When it is tied, this stitch forms a buttress or support with the pledget on top of the new commissure. This prevents blood from dissecting behind the valve repair during diastole. The right coronary cusp is again probed with a blunt sucker tip to demonstrate its competency following oblitera- tion of the prolapse.

The aorta is closed and attention is turned to repair of the VSD. The competency of the aortic valve can be observed while cardioplegia solution is injected in the aortic root and the aortic valve is viewed through the VSD. Later, during rewarming, when the aortic clamp has been removed, left ventricular vent return is again measured to determine pres- ence or absence of significant aortic insufficiency.

marking stitch in corpora arantii

redundancy of left coronary cusp

> L

FIGURE 5-20. In another patient,

the proximal ascending aorta has been opened. The aortic valve has three leaflets with distention and stretching of the left coronary cusp.

A marking stitch is placed in the

corpora arantii of the right and non-

coronary cusps. The left cusp is

pulled toward the patient's left and

redundancy in this leaflet is seen at

the right-left cusp commissure. The

corpora arantii marking suture is

then placed additionally in the

adjacent region of the new left coro-

nary cusp.

aortic wall

felted imbricating sutures

FIGURE 5-21. Two felted mattress sutures are placed in the redundant portion of the left coronary cusp. These are placed through the wall of the aorta and supported with addi- tional pledgets before tying them outside the aorta. With such, the redundant portion of the leaflet is excluded from the valve apparatus and attached to the lateral aortic wall.

The left coronary cusp is now the same size as the other two leaflets.

felted stitch on top of commissure

caud

FIGURE 5-22. A felted mattress suture is placed on top of the new left-right cusp com-

missure to prevent blood from dissecting behind the valve repair during diastole.

ceph

R<- - • L caud

coronary cusp

"wind sock"

and fenestration

FIGURE 5-23. In another patient, the aortic valve is viewed through a proximal ascending aortotomy. A 1-mm probe is passed into the dilated central portion of the right coronary cusp. There is a discrete fenestration in the end of this wind sock.

ceph R « - - • L

caud

fenestration in "wind sock"

FIGURE 5-24. The valve cusp is lifted and the fenestration at the end of the wind sock in

the right coronary cusp is seen.

ceph R < -

caud

repair stitch of cephalad surface of valve cusp

FIGURE 5-25. The cusp is repaired with a single pledgeted mattress suture placed across the fenestration on the upper surface of the right coronary cusp.

5-3. Inlet Ventricular Septal Defect

Perimembranous inlet or Type 3 or AV canal type of VSD are located adjacent to the tricuspid valve annulus but posterior and inferior to the region of the mem- branous septum. A related anomaly is left ventricle to right atrium tunnel or com- munication. This defect is possible by virtue of the fact that normally the tricuspid valve annulus is located slightly inferior to the mitral valve annulus. With lack of ventricular septal formation in this spot, a direct communication between the left ventricle and right atrium can occur. As an isolated defect, the opening in the right atrium is cephalad or above the tricuspid valve annulus.

FIGURE 5-26. This child has

been placed on cardiopul- monary bypass and the heart arrested with aortic clamping, cardioplegia, and profound local cooling. The right atrium has been opened. There is a direct communication between the left ventricle and right atrium located above the tricuspid valve annulus. This defect is closed with multiple stitches and a Dacron® patch.

anterior leaf of tricuspid valve

tricuspid valve annulus

left ventricle to right atrial communication

ceph 4*

R < -

caud

ceph R < - - > L

caud

membranous ventricular septum

VSD

septal leaf of tricuspid valve

FIGURE 5-27. In another patient the right atrium is opened and the defect is located infe- rior and posterior to the region of the membranous ventricular septum. Exposure of these defects through the atrium is excellent.

ceph R « - - > L

caud

anterior leaf of tricuspid valve

septal leaf of tricuspid valve

region of His' bundle

FIGURE 5-28. Multiple interrupted mattress sutures with felt pledgets are placed around

the rim of the VSD. Posteriorly, these stitches are passed through the base of the septal

leaf near the annulus. The His' bundle is located at the posterior inferior margin of the

VSD so stitches here are placed superficially. More anterior stitches are placed directly in

the muscular septum.

ceph R « -

caud

anterior leaf of tricuspid valve

septal leaf of tricuspid valve

FIGURE 5-29. Stitches are placed in a Dacron® patch and tied to complete the repair.

5-3-1. Inlet Ventricular Septal Defect with Straddling Tricuspid Valve

ceph R < -

caud

anterior leaf of tricuspid valve

septal leaf of tricuspid valve

papillary muscle

FIGURE 5-30. In another patient, working through a right atriotomy, the VSD is located

beneath the large tricuspid valve septal leaf. Tricuspid valve chordae arise from the left

ventricle.

ceph

R<- - • L caud

ventricular septal defect

papillary muscles attached in left ventricle

FIGURE 5-31. On careful inspection there are two large anomalous papillary muscles to the tricuspid valve both of which arise from the left ventricular chamber.

ceph R < - - • L

caud

detached papillary muscles

FIGURE 5-32. Both large papillary muscles are divided at the base. Multiple stitches are

placed around the rim of the VSD.

FIGURE 5-33. A Dacron® patch is stitched over the VSD. The two anomalous papillary muscles will be re-implanted at appropriate sites on the right ventricular sur- face of the ventricular septum using multiple interrupted simple stitches.

Dacron patch

detached papillary muscles

caud

5-4. Muscular Ventricular Septal Defect

These defects can occur in any part of the muscular ventricular septum. Preop- erative definition of the number of VSDs and the precise location of each by echocardiography or angiography is useful to the surgeon at the time of repair.

The best exposure for most muscular defects is through a right atriotomy. An unusual location may warrant a high or an apical right ventriculotomy. In the presence of multiple low VSDs an apical left ventriculotomy may be optimal.

FIGURE 5-34. Cardiopulmonary bypass is established in conjunc- tion with aortic cross-clamping, cardioplegia, and profound local cardiac cooling. The right atrium is opened, and the septal tricus- pid valve leaflet is retracted. A large muscular VSD is seen beneath this leaflet. There is a cephalad muscular rim of VSD that separates it from the tricus-

pid valve. caud

VSD

septal leaf of tricuspid valve

>L

Dacron patch

FIGURE 5-35. Multiple interrupted stitches with Teflon® felt pledgets are placed around the rim of the VSD. The His' bundle is located adjacent to the tricuspid valve annulus beneath the septal leaflet. Stitches in this area are placed superficially to avoid the His' bundle. Remaining stitches are inserted on the right ventricular surface of the septum, passing through approximately 50% of the thickness of the septum. The stitches are placed in a knitted Dacron® patch that is positioned beneath tricuspid leaflet chordae to avoid entrapment of same.

septal leaf of tricuspid valve

tip of clamp

FIGURE 5-36. In this child, expo- sure is through a right atriotomy.

The muscular VSD is located beneath the posterior aspect of the septal tricuspid valve leaflet.

For identification, a right-angle

clamp is passed through an atrial

septal defect (ASD) and the

mitral valve, with the tip present-

ing in the muscular VSD. There is

a muscle ridge along the poste-

rior margin of the VSD and

beneath the septal leaflet and the

His' bundle is located in this

region. In some cases, the VSD is

in continuity with the tricuspid

valve annulus, and the His'

bundle is located in the posterior

inferior corner of the defect. This

muscular VSD will be closed with

felted interrupted sutures and a

knitted Dacron® patch.

ceph R < - - • L

caud

mid muscular VSD

septal leaf of tricuspid valve

FIGURE 5-37. In another child, a large muscular VSD is exposed through a right atriotomy.

This defect is in the midmuscular septum and is retracted into the field with a metal clamp that is passed through the septal defect. In some cases trabeculations hide the true rim of a muscular VSD, in which case care must be taken to adequately expose all margins of the VSD. With this exposure stitches can be placed around the rim of the defect being careful to avoid incomplete closure and a residual VSD.

FIGURE 5-38. In this child, the

precise location of a high muscular VSD was determined intraopera- tively. The right ventricle was explored through a right atri- otomy, but no VSD was seen ini- tially. With the left ventricular vent clamped, excessive red blood was noted in the right ventricular outflow tract. A high right ven- triculotomy was made as shown here. A septal defect was found by passing a probe amongst trabecu- lations in the left upper part of the infundibulum. If a high VSD cannot be located with the above approach, the ventricular septum is inspected through the proximal ascending aorta while retracting the aortic valve.

region of pulmonic valve

trabeculations covering high muscular VSD

ceph

caud

- • L

high muscular VSD in left lateral area of outflow tract

FIGURE 5-39. After trabeculations are resected, a large muscular VSD is seen.

ceph R < -

caud

region of pulmonic valve

patch

FIGURE 5-40. Interrupted felted mattress sutures are passed through the right ventricular

surface of the septum, surrounding the VSD. The defect is then closed with stitches placed

in a knitted Dacron® patch.

R ^

ventricular septal defect

FIGURE 5-41. In this child, it was not possible to adequately expose an apical muscular VSD by working through a right atriotomy. A short apical right ventriculotomy allowed excellent exposure of the defect.

ceph R < - - * L

caud

patch

FIGURE 5-42. A Dacron® patch is stitched over the VSD with interrupted felted mattress

sutures.

indicated to protect the lungs and to avoid development of pulmonary vascular obstructive disease when total repair of intracardiac anomalies is not possible or should be delayed until an older age. Banding can be performed through a left or right thoracotomy or median sternotomy, regardless of the position of the great vessels. Ideally, it is carried out through a fourth interspace lateral thora- cotomy on the side ipsilateral to the main pulmonary artery. A SILASTIC®- impregnated Teflon® band is passed around the mid main pulmonary artery. If the band is placed more proximally and over the commissures of the pulmonary valve, thickening of valve leaflets may occur after surgery, which may result in development of a dysplastic pulmonary valve. If the band is placed too distally on the main pulmonary artery, it may encroach on and kink one or both pul- monary artery branches.

During banding, distal pulmonary arterial pressure is monitored by placing a small plastic catheter through a purse string suture. A second plastic catheter is placed in the ascending aorta for blood sampling and measurement of systemic pressure, although the same can be accomplished with a peripheral arterial catheter inserted before thoracotomy. Ideally, banding should reduce distal main pulmonary artery mean pressure to 25 to 30mmHg or 30% to 50% of mean sys- temic pressure. In most cases before banding, pulmonary arterial pressure will be equal to systemic pressure. When pulmonary vascular resistance is low before banding, mean pulmonary arterial pressure may be low. In this case, the pul- monary artery is constricted until there is a rise in systemic pressure. The final postband pressures should be similar to those mentioned above for children who initially have pulmonary artery hypertension.

If systemic outflow tract obstruction is present, the band has to be placed loosely, and ideal pressure changes may not be accomplished; this avoids ven- tricular hypertension as the result of double outlet obstruction. To check for this after banding is complete, a needle is passed into the distal main pulmonary artery and then proximal to the band to measure intraventricular pressure.

Peripheral arterial oxygen saturation (Fi0

= 0.5) should not change with

banding. A drop of 5% is acceptable in patients with normally related great

vessels. In the presence of d-transposition a drop of 10% is acceptable, but periph-

eral arterial oxygen saturation should not be reduced below 65% to 70%.

ant caud<- - • c e p h

post

catheter in ascending aorta

catheter in distal main pulmonary artery

constricting band around mid main pulmonary artery

FIGURE 5-43. Through a left fourth intercostal space thoracotomy and a pericardiotomy at the base of the heart, a left-sided main pulmonary artery is exposed. The band around the main pulmonary artery has been progressively tightened with interrupted sutures until the desired pressure changes are seen. It is fixed to the adventitia of the proximal main pulmonary artery with interrupted sutures that are placed on one half to two thirds of the circumference of the main pulmonary artery. The monitoring catheters in the distal pul- monary artery and ascending aorta are in place.

5-5-7. Band Removal at the Time of Total Repair

ceph R « -

caud

main pulmonary arterotomy

band ends separated

FIGURE 5-44. On cardiopulmonary bypass, band stitches are removed and the ends of the

band separated. A longitudinal incision is made in the anterior wall of the main pulmonary

artery at the band site.

ceph R < - - • L

caud

intimal fibrous ridge

FIGURE 5-45. After all sutures are removed, the band can be removed from its bed. A pos- terior fibrous ridge over the band tunnel remains, and this tissue must be excised to prevent residual obstruction.

ceph R < - - > L

caud

fibrous ridge incised to open bed of previous band

FIGURE 5-46. The fibrous ridge is incised transversely on the inner surface of the pul-

monary artery to expose the intact adventitia of the lateral and posterior main pulmonary

artery.

ceph R < -

caud

fibrous ridge

FIGURE 5-47. The fibrous ridge is excised also removing loose intimal tissue.

ceph R < -

caud

bed of previous band

FIGURE 5-48. The smooth adventitia of the posterior main pulmonary artery is intact. If

it were not, the intima would be approximated with a continuous suture.

R ^

pericardial patch

FIGURE 5-49. An oval pericardial patch of generous size is sutured over the anterior main pulmonary artery.

ceph R « - - • L

caud

pericardial patch

FIGURE 5-50. With placement of the pericardial patch, the main pulmonary artery is

enlarged anteriorly to avoid stenosis of the vessel. The posterior fibrous rim has been

removed to avoid obstruction to flow in this area, which can occur if only anterior peri-

cardial patch enlargement is used.