4 Endocardial Cushion Defects
Babies born with these anomalies have a deficiency of the atrial septum, ven- tricular septum, and/or abnormalities of the atrio-ventricular (AV) valves. In partial AV canal defect, there is absence of the septum primum and usually a cleft in the anterior mitral leaflet. This anomaly is synonymous with primum atrial septal defect. The intermediate form of AV canal encompasses a primum atrial septal defect, ventricular septal defect usually in the inlet position, and usually a cleft mitral valve. The annulus between tricuspid and mitral valves is intact. In complete AV canal, the primum atrial septal defect is in continuity with a high ventricular septal defect because there is no annular continuity of mitral and tri- cuspid valves. This results in a single intracardiac AV valve that functions as both mitral and tricuspid valves. All patients have a significant left-to-right intracar- diac shunt and in the presence of complete AV canal there is always severe pul- monary hypertension with or without AV valve regurgitation. Early surgery is necessary because of congestive heart failure and, in the presence of pulmonary artery hypertension, to avoid early development of pulmonary vascular obstruc- tive disease.
Other forms of canal deformities not in this classification are common atrium and, some feel, isolated mitral valve cleft.
A primary totally corrective operation is almost always performed. In the rare case of a very small and severely nutritionally deprived neonate with complete AV canal, placement of a temporary pulmonary artery band for a few months may allow significant nutritional improvement prior to totally corrective surgery.
In the asymptomatic child with partial AV canal, corrective surgery is performed in the early years of life. For the intermediate and complete forms of AV canal, the repair is carried out in the early months of life. Regardless of the lack of symptomatology, the ideal age for total repair is 2 to 4 months.
Repair of these anomalies is performed working through a right atriotomy using cardiopulmonary bypass, moderate hypothermia, aortic cross-clamping and cardioplegia, profound local cardiac cooling, and left ventricular venting.
37
ceph R « - - > L
caud
cephalad rim of atrial septal defect
mitral chord supports cephalad part of anterior mitral leaflet
tricuspid septal leaflet is absent
cleft in mitral leaflet extends to annulus
fibrous
thickening along margin of mitral valve cleft
FIGURE 4-1. The patient is on cardiopulmonary bypass, and a right atriotomy has been made. The low primum atrial septal defect (ASD) allows excellent exposure of the ante- rior mitral leaflet, which is lifted into the field. There is a cleft that separates the leaflet into cephalad and caudad components, and it extends to the common annulus between mitral and tricuspid valves. Chordae support the rim of this leaflet at the cleft, and no evi- dence of mitral regurgitation is apparent. There is thickening and fibrosis of the leaflet above and below the cleft; this provides tissue of good substance into which stitches can be placed for the repair. There is a deficiency or absence of the adjacent tricuspid valve septal leaflet.
rim of primum atrial septal defect
tip of right angle clamp passes through small ventricular septal defect
ceph
caud - • L
FIGURE 4-2. The area beneath the atrio-ventricular valves is inspected for small ventricular septal defects. The tip of a right- angle clamp passes beneath the tricuspid valve leaflet and through a small ventricular septal defect.
caud
stitches in mitral valve cleft
first ASD repair stitch placed on RV surface of inlet septum
thickened mitral leaflet at margin of cleft
FIGURE 4-3. The mitral valve cleft is repaired with multiple simple interrupted sutures.
The thick fibrous margin of the cleft can be seen. Care is taken not to close the cleft exces- sively to avoid iatrogenic mitral stenosis, although ideally the cleft is closed to the free margin of the leaflet. The first ASD repair stitch is placed as a mattress suture with a Teflon® felt pledget opposite the cleft. This stitch is placed in the upper ventricular septum along the right ventricular surface and is used as a traction suture during repair of the cleft.
caud
rim of ASD
interrupted mattress sutures for ASD repair passed through septal muscle or in base of tricuspid leaflet
mitral leaflet attachment beneath coronary sinus
stitches
beneath coronary sinus near His' bundle
FIGURE 4-4. Additional interrupted mattress sutures with felt pledgets are placed in the upper margin of the ventricular septum or passed through the base of the tricuspid leaflet to be used in closing the lower rim of the ASD. Interrupted sutures are placed in tissue beneath the coronary sinus in the region of the His' bundle placing them superficially and on the left atrial surface of the septum. The posterior annulus attachment of the anterior mitral leaflet is immediately adjacent to the coronary sinus in some cases, and stitches can be safely placed at the base of this leaflet to avoid the His' bundle.
ASD inferior repair stitches are tied
R +
caud
FIGURE 4-5. A knitted Dacron® patch is cut to the size and shape of the ASD and the mattress sutures are passed through the patch. Stitches along the inferior rim of the ASD are tied. The aortic clamp is removed, and rewarming started. When normal sinus rhythm is observed, the stitches beneath the coronary sinus are tied. If these stitches are too near the His' bundle, heart block will be observed immediately when the offending stitch is tied. If this occurs, the stitch is removed and replaced. The upper margin of the ASD is closed with a continuous suture while rewarming continues.
4-1-1. Primum Atrial Septal Defect with Mitral Leaflet Tissue Deficiency
ceph R < - - • L
caud
rim of ASD
leaflet deficiency at base of cleft
stitches in cleft near free margin of leaflet
FIGURE 4-6. In another child, cardiopulmonary bypass has been established and the right atrium opened. There is an area of tissue deficiency at the base of the mitral valve cleft near the annulus. Primary closure of this part of the cleft was thought inadvisable for fear this would cause distortion of the mitral leaflet and mitral regurgitation.
ceph R « - - • L
caud
pericardial patch in area of leaflet deficiency
FIGURE 4-7. The mitral valve cleft near the free margin of the leaflet is closed primarily.
A triangular-shaped pericardial autograft is stitched over the area of leaflet deficiency near the annulus. The primum ASD is then closed in the usual way.
4-2. Common Atrium
ceph R < - - • L
caud
left atrial appendage
mitral valve
right pulmonary veins
FIGURE 4-8. The child has been placed on cardiopulmonary bypass, and the view is looking through a right atriotomy. There is no atrial septum, and the orifices of the left atrial appendage and right pulmonary veins are seen in the posterior wall of the common atrial chamber. The mitral valve is anterior to the left atrial appendage.
R <
left atrial appendage
common AV valve annulus
tricuspid valve
mitral valve
FIGURE 4-9. The mitral valve is anterior to the left atrial appendage. The mitral and tri- cuspid valves share a common annulus.
FIGURE 4-10. As is the case in most endocardial cushion defects, there is a cleft in the ante- rior mitral leaflet, and it is repaired primarily with interrupted sutures. This is important, even in the absence of mitral regurgitation, because closure of the cleft supports the ante- rior mitral leaflet and may prevent later development of valvular regurgitation. The repair should not be excessive, to cause iatrogenic mitral stenosis; although ideally the cleft should be closed to the free margin of the leaflet. The extent of the repair is also deter- mined by measuring the valve orifice with sized dilators to compare these numbers to the predicted mitral orifice based on body surface area.
FIGURE 4-11. A knitted Dacron®
patch is placed in the position of the atrial septum. Interrupted sutures are placed in the AV valve common annulus and beneath the coronary sinus adjacent to the AV node and His' bundle. The interrupted sutures near the AV valves are tied with the heart arrested with cardioplegia.
The aortic cross-clamp is then removed, and the heart is allowed to beat in sinus rhythm. The sutures near the His' bundle are then tied so that normal sinus rhythm can be observed during this part of the pro- cedure. If injury to the His' bundle occurs because of these stitches, complete heart block is seen imme- diately as they are tied. Offending sutures are removed and replaced.
A continuous suture is then placed posteriorly and cephalad to secure the patch to the atrial wall during rewarming.
Dacron patch
interrupted sutures in AV valve common annulus
interrupted sutures beneath coronary sinus and His' bundle
caud
> L
4-3. Inlet Ventricular Septal Defect
The inlet ventricular septal defect is located in the endocardial cushion position and is also known as a perimembranous inlet or Type III ventricular septal defect.
FIGURE 4-12. The septal and anterior tricuspid valve leaflets are retracted to expose the VSD. The defect is located pri- marily beneath the septal leaflet. This position places it caudad to the location of a typical Type II or perimembra- nous VSD. Exposure through the right atrium is enhanced due to the more caudad loca- tion of the VSD. A secundum atrial septal defect is also present.
anterior leaflet of tricuspid valve
VSD
atrial septal defect
septal leaflet of tricuspid valve
ceph
caud - • L
R <
stitches at base of septal leaflet of tricuspid valve stitches near His' bundle
coronary sinus atrial septal defect
FIGURE 4-13. Interrupted mattress sutures are placed along the rim of the VSD. At the base of the tricuspid valve septal leaflet, these sutures may be passed through the leaflet near the annulus. The His' bundle is located near the posterior inferior rim of the VSD in the region anterior to the coronary sinus. Sutures here must be placed superficially along the right ventricular surface of the rim of the VSD to avoid His' bundle injury.
Dacron patch
tricuspid valve septal leaflet
atrial septal defect
FIGURE 4-14. Stitches are placed in a knitted Dacron® patch and tied. Part of the patch is hidden from view beneath the tricuspid valve septal leaflet. The ASD will be closed with a separate Dacron® patch.
4-4. Complete Atrioventricularis Communis or Atrio-Ventricular Canal
ceph R < - - • L
caud
primum atrial septal defect
ventricular septal defect beneath AV valve leaflets
secundum atrial septal defect
FIGURE 4-15. Exposure is through a right atriotomy. A primum ASD is in the lower or caudad part of the atrial septum, and it is in continuity with a high VSD located beneath the flaccid AV valve leaflets. In this child, a secundum ASD is also present.
ceph R < - - > L
caud
common anterior leaflet of AV valve chord attaching common anterior leaflet to ventricular septum
ventricular septum tricuspid orifice
mitral orifice
common posterior leaflet of AV valve
FIGURE 4-16, The common anterior leaflet of the AV valve or anterior bridging leaflet extends over the tricuspid and mitral valve orifices. Similarly, the common posterior leaflet or posterior bridging leaflet of the AV valve extends over both valve orifices. There is no fibrous annular continuity of the mitral and tricuspid valves. Here, there are chordae that attach the common anterior leaflet to the ventricular septum (Type A AV Canal by the Rastelli classification).
ceph R < - - • L
caud
chordal attachments of common anterior leaflet of AV valve are only to RV papillary muscle
right ventricular papillary muscle
FIGURE 4-17. In this child, there are chordal attachments from the common anterior leaflet only to a papillary muscle in the right ventricle (Type B AV Canal by the Rastelli classification).
R +
free floating common anterior leaflet of AV valve without chordal attachments to ventricular septum
ventricular septum
FIGURE 4-18. The common anterior leaflet is free floating with no chordal attachments to the ventricular septum (Type C Complete AV Canal by the Rastelli classification).
4-4-1. Complete Atrio-Ventricular Canal: Patch Repair
ceph R < - - > L
caud
FIGURE 4-19. The common anterior leaflet of the AV valve is undivided. When the one- patch technique for repair is used, this leaflet is surgically divided to the annulus, leaving slightly more tissue on the mitral valve portion of the leaflet.
ceph R < > L
caud
common anterior leaflet of AV valve
FIGURE 4-20. The common anterior leaflet of the AV valve in this child is naturally divided.
The cleft or division in this valve may be used in the one-patch repair. If the mitral valve is deficient, the natural cleft may be closed in favor of a surgically created division toward the tricuspid valve portion of the leaflet so as to enlarge the mitral portion of the leaflet.
ceph R « - - • L
caud
common anterior leaflet of AV valve
common posterior leaflet of AV valve
FIGURE 4-21. The common posterior leaflet of the AV valve may be naturally divided (less common) or in this case surgically divided to near the posterior annulus. The common anterior leaflet was also surgically divided. This is the first step in the one-patch repair of complete AV canal.
ceph R « - - • L
caud
mitral portion of common anterior leaflet
mitral portion of common posterior leaflet
FIGURE 4-22. The mitral portions of the common anterior leaflet and common posterior leaflet, respectively, have been approximated with interrupted sutures placed at the extremes of the mitral leaflet repair. Ideally the mitral valve is closed to the free margin of the new leaflet, and the proposed mitral orifice is measured with sizers after repair to prevent iatrogenic mitral stenosis.
mitral portion of common anterior leaflet
mitral portion of common posterior leaflet
FIGURE 4-23. The mitral leaflet repair is completed with simple interrupted sutures. The newly constructed anterior mitral valve leaflet is now free floating. The new mitral orifice must be carefully measured using sized dilators. The opening is compared to a normal valves based on body surface area to avoid excessive closure of the valve, which may result in iatrogenic mitral stenosis.
R ^
new anterior mitral leaflet
ventricular septum
ventricular septal defect
caud
FIGURE 4-24. The new anterior mitral leaflet is lifted to expose the ventricular septal defect beneath. To close the VSD, felted horizontal mattress sutures will be placed on the right ventricular surface of the upper rim of the ventricular septum.
ceph R < - - • L
caud
knitted Dacron patch
felted mattress sutures in ventricular septum
region of His' bundle
sutures beneath coronary sinus
FIGURE 4-25. A knitted Dacron® patch is cut to conform to the size and shape of the VSD and primum ASD. Stitches previously placed in the upper rim of the ventricular septum are placed in the lower rim of the Dacron® patch and tied. The most posterior ventricu- lar septal defect stitches are near the His' bundle and should be placed slightly remote from the rim of the ventricular septum. Additional felted mattress sutures are placed superficially in the tissue beneath the coronary sinus. These sutures are in the region of the His' bundle and are tied after the aortic cross-clamp is removed and the heart is beating in sinus rhythm. If the His' bundle is damaged by these sutures, heart block will occur when they are tied. In this event, the sutures are removed and placed again.
reconstructed anterior mitral leaflet
ventricular septal defect closed by lower part of Dacron patch
stitches beneath coronary sinus
ceph
caud - • L
FIGURE 4-26. The Dacron® patch is retracted anteriorly to expose the ventricular septal defect beneath the new anterior mitral leaflet.
Felted mattress sutures will be placed in the base of this leaflet near the Dacron® patch.
Chordae of this leaflet are left intact. The sutures will be passed through the Dacron®
patch at an appropriate level on the patch to mimic the position of the mitral leaflet in its natural position during ventricular systole.
Care must be exercised to avoid positioning the leaflet too far cephalad on the patch, which might result in a tented and immobile leaflet. It is better to err on the side of attach- ing the leaflet nearer the ventricular septum.
These valve-fixing sutures can also be passed through the adjacent tricuspid leaflets on the right ventricular surface of the patch.
ceph
R^- - • L
caud
mitral leaflet attached to patch by felted mattress sutures
retracted Dacron patch
stitches beneath coronary sinus
FIGURE 4-27. The new anterior mitral leaflet is attached to the Dacron® patch by felted mattress sutures that have been tied.
ceph R««- - > L
caud
tricuspid valve leaflet attached to Dacron patch
stitches beneath coronary sinus
FIGURE 4-28. The right atrial surface of the patch is seen. Mitral valve sutures passed through the patch have also passed through the tricuspid valve leaflets, and the stitches are tied. Stitches beneath the coronary sinus are now passed through the adjacent patch and the aortic clamp is removed to commence rewarming. When conducted rhythm is observed, the coronary sinus stitches are tied. If the His' bundle is damaged when these stitches are tied, heart block is seen immediately. In that event offending sutures are removed and replaced.
ceph R « - - • L
t caud
upper part of Dacron patch stitched over primum atrial septal defect
FIGURE 4-29. While rewarming continues, the upper part of the Dacron® patch is stitched to the atrial septum with a continuous suture. The right atriotomy is closed, and a left atrial pressure monitoring line is placed in the ventricular vent site near the right upper pul- monary vein shortly before discontinuing cardiopulmonary bypass.
ceph R < - - • L
caud
Dacron patch closing atrial septal defect
reconstructed tricuspid valve leaflets
FIGURE 4-30. In this child, 2.5 months after corrective surgery, the Dacron® patch is endothelialized, depicting the fate of the Dacron® material used in this repair.
4-4-2. Complete Atrio-Ventricular Canal: Double-Patch Repair
Currently this is my preferred repair. Iatric incisions in the bridging leaflets are avoided and there is less risk of valve repair breakdown following surgery. This is especially important because most AV repairs today are performed in young small infants with more fragile valvular tissue.
FIGURE 4-31. The exposure is through a right atriotomy after the infant is placed on cardiopulmonary bypass. The high VSD is in continuity with the low primum ASD. There is a single intracar- diac AV valve comprised of common anterior and common posterior leaflets that span across the septal defects from left heart to right heart. Stay sutures have been placed in these valve leaflets for optimum exposure.
common anterior leaflet ventricular septal defect common posterior leaflet primum atrial septal defect
caud
R**
common anterior leaflet
chords at free margin of proposed new anterior mitral leaflet
posterior leaflet
FIGURE 4-32. The leaflets are carefully inspected and in most patients a fibrous rim of jet lesion demarks the point where the leaflets naturally come together during systole. This fibrous tissue is useful during the valve repair to close the new cleft because of its sub- stance and ability to hold sutures. Both valve leaflets are inspected in order to identify the point where chordae attach to what will be the new free margin of the new anterior mitral leaflet. Great care is taken at this point in the operation to precisely define the point where the common anterior and common posterior leaflets will meet to form the new anterior mitral leaflet to avoid asymetric apposition. The surgeon can also inject saline under pres- sure in the ventricular chambers to open the valve leaflets to help identify the proper alignment for repair.
common anterior leaflet
marking stitch at free margin of new anterior mitral leaflet
common posterior leaflet
FIGURE 4-33. When the point on the anterior and posterior leaflets near the left atrium and near the chordal insertions has been identified, a marking suture is placed to bring these points together. This posterior marking stitch is left in place during subsequent of the repair.
ceph R « - - > L
•
caud
marking stitches at base of new anterior mitral leaflet cleft
marking stitch at free margin of new anterior mitral leaflet
FIGURE 4-34. Marking sutures are then placed at the more anterior extreme of the pro- posed anterior leaf mitral valve cleft and these are tied. These markers are left in place but do not impede exposure during the repair prior to cleft closure.
Dacron patch for VSD repair
ventricular septal stitches
FIGURE 4-35. The felted mattress sutures are placed along the right ventricular surface of the upper margin of the ventricular septum adjacent to the ventricular septal defect. Pos- teriorly, these sutures are placed more superficially and somewhat remotely from the rim of the VSD in order to avoid the bundle of His' located in this region. Sutures are then passed through a knitted Dacron® patch that is cut to the size and shape of the VSD.
Although the upper rim of the patch here is shown to be flat, that edge is often scalloped to allow a better fit for the new valve leaflets that will be attached here.
stitches in upper rim of VSD patch
VSD repair patch
FIGURE 4-36. The VSD patch has been placed over the defect and the septal rim stitches tied. Nonfelted sutures are next passed through the upper rim of the patch. The size of the patch and the shape of the upper rim are such that after completing the repair the AV valve leaflets will rest on the patch in a position similar to that during end systole.
• • v £ —
common anterior leaflet
ceph
stitches passed through common anterior leaflet
VSD repair patch R < - - > L
caud
FIGURE 4-37. The stitches in the upper rim of the VSD patch are passed through the common anterior and common posterior valve leaflets, respectively. The previously placed marking sutures indicate the line of these sutures so that the previously selected valve tissue can be placed appropriately on the mitral or tricuspid side of the patch. Generally, around two thirds of the undivided bridging leaflets are placed on the mitral valve side.
If there is a natural division on the bridging leaflet, the transvalvular stitches can be placed in the base of the natural division of the leaflet.
ceph R < - - > L
caud
VSD repair patch
stitches repairing cleft in anterior mitral leaflet
stitches through common posterior leaflet
FIGURE 4-38. Interrupted fine monofilament sutures are now used to close the cleft in the new anterior mitral leaflet. At this point the transvalvular stitches from the upper rim of the VSD patch are left untied. The new mitral valve orifice is measured carefully and the size compared with normal values in order to avoid excessive closure of the cleft and iatro- genic mitral stenosis.
ceph R«*- - • L
caud
patch to close atrial septal defect
FIGURE 4-39. A second Dacron® patch is cut to conform to the size and shape of the primum ASD.
AV valve separating stitches in ASD patch
FIGURE 4-40. The transvalvular stitches from the upper rim of the VSD patch are placed through the base of the ASD patch.
R ^
ASD patch
stitches beneath coronary sinus
coronary sinus
FIGURE 4-41. The ASD patch has been lowered into position. Additional felted mattress sutures are placed superficially beneath the coronary sinus. If they can be placed toward the left atrium it is safer in order to avoid damage to the His' bundle which is in this region.
The stitches are passed through the ASD patch. Next, the stitches along the base of the patch are tied leaving the few stitches beneath the coronary sinus untied. The aortic clamp is removed and rewarming is commenced. One must await the observation of sinus rhythm before proceeding. Only after observing sinus rhythm are the interrupted sutures near the coronary sinus tied. If they are too near the His' bundle, third-degree block will be observed immediately and the offending stitch is removed and replaced.
VSD repair patch
ASD repair patch
FIGURE 4-42. Stitches across the base of the ASD patch have been tied, as have the stitches beneath the coronary sinus. The upper rim of the patch is attached to the atrial septum with a continuous suture to complete the repair. A left atrial line is left through the ventricular vent site near the right upper pulmonary vein.
4-4-3. Complete Atrio-Ventricular Canal: Modified Single-Patch Repair The concept of this complete AV canal repair includes obliteration of the VSD by attaching the AV valve leaflets directly to the top of the ventricular septum avoiding the need for placement of a patch beneath the AV valves. In theory this can be performed more rapidly than other repairs because the placement of the VSD patch is omitted. An additional advantage is avoiding a surgical incision in AV valve tissue (as in the standard one-patch technique), which is especially applicable in the small infant who may have fragile valve tissue. Of course, the same technique is also used in the classic two-patch repair. My bias is for use of the modified single-patch repair only in patients who have a very shallow VSD.
Otherwise, the AV valve leaflets may be distorted by attaching them in an unnat- ural position to the top of the ventricular septum which may result in significant residual mitral regurgitation.
This operation is performed with moderate systemic hypothermia, aortic cross- clamping, cardioplegia, and profound local cardiac cooling.
ceph R « - - • L
caud
common anterior leaflet
marking stitch in mitral valve cleft near free margin
marking stitch in mitral valve cleft near ventricular septum
common posterior leaflet
FIGURE 4-43. The child has been placed on cardiopulmonary bypass and cardioplegia delivered after applying the aortic cross-clamp. A right atriotomy is made. Initially the common anterior leaf and common posterior leaf are carefully evaluated to determine the appropriate position of the new cleft in the proposed new anterior mitral valve leaf.
The first marking stitch is placed between the common anterior and common posterior leafs, respectively, near the free margin of each leaflet. The location of the new free margin can usually be identified by insertion of chords at this point. The proposed cleft in the new anterior mitral valve leaf is identified and appropriate marking stitches placed at the septal end of this cleft.
ceph R < - - • L
caud
common anterior leaflet
natural division in leaflet
marking stitches in cleft near ventricular septum
common posterior leaflet
primum ASD rim
FIGURE 4-44. In this child, there is a natural division in the common anterior leaf. In order to enlarge the new mitral valve leaflet, this natural division will be closed so that the common anterior leaf can be divided by sutures nearer the tricuspid orifice.
caud
felted stitches in ventricular septum for VSD repair
shallow VSD
FIGURE 4-45. Felted mattress sutures are placed across the top of the ventricular septum on the right ventricular surface for the VSD repair. In this case, the VSD is shallow so that distortion of the valve should be minimal when these stitches are tied.
ceph
R<- - • L caud
VSD repair stitches passed through AV valve leaflets
FIGURE 4-46. The VSD repair stitches have been passed through the AV valve leaflets in order to separate them into tricuspid and mitral components.
ceph R « - - • L
caud SHMK
natural division in common anterior leaflet
— marker stitches in cleft
pnmum ASD
FIGURE 4-47. The natural division in the common anterior leaf and the new cleft in the new anterior mitral leaf are exposed. The original marking sutures are used to align the leaflets properly.
ceph R « -
stitches closing natural division in common anterior leaflet
cleft repair stitches
VSD repair
through A-V caud ^ S C I f f H V J I ^ ^ I H H I i ^ H I H H I H I I H ^ ^ ^ H H H H B k valve
FIGURE 4-48. Multiple simple sutures of fine polypropylene are placed to close the natural division in the common anterior leaflet and also to close the cleft in the new anterior mitral leaflet.
pnmum ASD
stitches beneath coronary sinus
FIGURE 4-49. Felted mattress sutures are placed beneath the coronary sinus for use in the ASD repair. These stitches are superficial and on the left atrial surface of atrial wall beneath the coronary sinus. Some of these stitches are placed in the annulus of the mitral valve because this is always remote from the His' bundle.
ceph R < -
caud - • L
felted VSD repair stitches
FIGURE 4-50. A patch cut to the size of the ASD is placed in the wound and the VSD repair sutures that pass through the AV valve leaflet tissue are now placed in this patch.
ceph R < - - > L
caud
VSD repair stitches
FIGURE 4-51. Stitches in the base of the Dacron® patch which pass through the AV valve leaflets are tied. With such the VSD is obliterated.
caud
repaired division in common anterior leaf
repaired anterior mitral valve leaflet
ASD patch
stitches beneath coronary sinus
FIGURE 4-52. Stitches placed beneath the coronary sinus are exposed and now these stitches will be placed in the Dacron® patch. The mitral valve cleft repair sutures are seen, as are the sutures that close the natural division in the common anterior leaf.
R ^
felted stitches in upper rim of ventricular septum
Dacron patch on top of AV valves
stitches beneath coronary sinus
FIGURE 4-53. The ASD patch is in position and the stitches beneath the coronary sinus are placed in the Dacron® patch. The aortic cross-clamp is now removed and rewarming is commenced. Cardiac rhythm may initially be abnormal but usually complete heart block will then convert to sinus rhythm. While observing sinus rhythm, the coronary sinus stitches are tied. If they have injured the His' bundle, heart block will be seen immedi- ately as they are tied. If such occurs the offending stitch is removed and replaced. Tying these sutures with a beating heart is safe because atrial tissue is not dynamic in con- tradistinction to tying ventricular septal stitches, which is almost always done with cardiac standstill.
ceph R < -
caud - • L
ASD patch
FIGURE 4-54. To complete the repair, the upper rim of the Dacron® patch is attached to the atrial septum with a continuous suture. A left atrial line is left through the ventricu- lar vent site near the right upper pulmonary vein.
4-5. Complete Atrio-Ventricular Canal and Tetralogy of Fallot
The surgical challenge of this uncommon anomaly is related to aortic overriding and the resulting necessity to place the VSD patch more anteriorly and around the aortic valve annulus in order to construct an unobstructed left ventricle to aorta tunnel. I prefer using a two-patch technique for this repair. With such, the dimensions of the VSD patch of appropriate size and shape are more easily pre- dicted. In most cases the complete repair can be performed working only through a right atriotomy while retracting AV valve leaflets. If the cephalad end of the VSD is difficult to repair through this exposure, a high right ventriculotomy should be performed for completion of the repair. When there is right ventricu- lar outflow tract hypoplasia, a transannular outflow tract patch is used rather than the placement of a homograft valved conduit even though early after surgery ventricular performance may be somewhat compromised by pulmonary insuffi- ciency. This disadvantage is offset by avoiding the need for homograft valve exchange due to patient growth, which would be necessary in most patients. If right ventricular dilatation and failure occur some years later, a valve can be placed at this time.
ceph R « - - > L
caud
main pulmonary artery
aorta
FIGURE 4-55. In this anomaly, the aorta is located more anteriorly than normal and over- rides the ventricular septum. The pulmonary valve and main pulmonary artery here are moderately hypoplastic.
R ^
atrial septal defect
common anterior AV valve leaflet
ventricular septal defect
caud
FIGURE 4-56. After cardiopulmonary bypass is established, and cardiac standstill achieved with aortic clamping and cardioplegia, a right atriotomy is made. The common anterior AV valve leaflet is free floating and undivided (Rastelli Type C), which is the usual case in this anomaly. A high VSD is in continuity with a low primum ASD.
common posterior AV valve leaflet
FIGURE 4-57. The common posterior AV valve leaflet is well formed and undivided. It is attached to the upper margin of the ventricular septum by multiple chordae.
ceph R < - - • L
common anterior AV valve leaflet
aortic valve
ventricular septum
caud
FIGURE 4-58. The common anterior AV valve leaflet is retracted. The VSD is located in the upper ventricular septum. With overriding of the aorta, the aortic valve is located, in part, over the right ventricle.
ceph R < -
caud - b i -
ventricular septal defect closure stitches
FIGURE 4-59. Interrupted multifilament mattress sutures with Teflon® felt pledgets are placed along the upper margin of the ventricular septum. Posteriorly, stitches are more superficial and slightly remote from the VSD to avoid the area of conductive tissue, which is located in this region. Anteriorly, stitches are placed as far as the exposure will allow.
The final VSD closure stitches at the anterior extreme of the VSD will subsequently be placed working through a high right ventriculotomy.
common anterior AV valve leaflet
patch closing ventricular septal defect
common posterior AV valve leaflet
> L
FIGURE 4-60. The VSD repair stitches have been placed in a Dacron® patch and tied.
This patch is wider and more redundant at the anterior end beneath the common anterior AV valve leaflet, which is nec- essary because the anterior end of the VSD incorporates the aortic valve. Additional patch material is needed to stitch around the annulus of the valve that is located in the right ventricle.
ceph R < - - • L
caud
stitches from upper rim of VSD patch passed through AV valve leaflets
FIGURE 4-61. Sutures are then passed through the upper rim of the VSD patch adjacent to the AV valve leaflets. The stitches are passed through the valve to separate this into separate mitral and tricuspid components.
R ^
valve
separating sutures
cleft in new anterior mitral valve leaflet
FIGURE 4-62. A cleft is now created by approximating adjacent mitral portions of the common anterior and common posterior AV valve leaflets, respectively. The VSD patch is seen beneath the valve leaflets while the valve separating sutures pass through the AV valve leaflets.
ceph
R<- -+L
caud
repaired cleft
FIGURE 4-63. Multiple stitches are used to close the cleft in the new anterior mitral leaflet.
stitches beneath coronary sinus
FIGURE 4-64. A second Dacron® patch is cut to conform to the ASD. The AV valve sep- arating stitches are placed in the base of this patch and tied. Additional stitches are placed beneath the coronary sinus and then passed through the posterior margin of the new patch. These stitches are placed superficially and in tissue nearer the adjacent mitral valve leaflet in order to avoid the His' bundle.
ASD patch
stitches beneath coronary sinus
FIGURE 4-65. The aortic cross-clamp is removed and warming commenced. After sinus rhythm is observed, the stitches beneath the coronary sinus are tied. If these injure the His' bundle, tissue heart block will be observed immediately on the electrocardiogram (EKG) tracing and the stitches are replaced. The upper rim of the ASD patch is then stitched to the margin of the ASD.
main pulmonary artery
ventriculotomy
caud
FIGURE 4-66. In this child, it was not possible to repair the anterior and cephalad end of the VSD working through the atriotomy. In addition, the right ventricular outflow tract was restrictive due to infundibular muscle obstruction and a small pulmonary valve annulus, so a high right ventriculotomy is made.
ceph R < - - • L
t caud
VSD patch
unclosed VSD
FIGURE 4-67. The upper end of the VSD patch is seen and additional stitches are placed to attach this end of the patch to the ventricular septum.
ceph R < - - > L
caud
main pulmonary artery
tissue outflow tract patch
FIGURE 4-68. The right ventricular outflow tract is restrictive above the infundibulum and the ventriculotomy is extended across the pulmonary valve annulus and proximal main pulmonary artery. A pericardial patch is used here to suture over the right ventricular outflow tract for reconstruction. Currently, a Gore-Tex® patch or a homograft pulmonary artery wall patch is preferred in this position.
R ^
patch in outflow tract
FIGURE 4-69. The completed outflow tract reconstruction is shown with the tissue patch placed over the upper right ventricle and proximal main pulmonary artery.
