S. Bert Litwin, MD. Preface

Transcription

1 Preface Because of the wide variety of anomalies encountered in congenital heart surgery, a broad understanding of the pathologic anatomy of defects is vitally important to the surgeon. More than in many other fields of surgery, a feel for three-dimensional spatial relationships of anomalies is helpful in allowing the operating surgeon to improvise technical details of a procedure. Precisely shaping and sizing an intraventricular baffle or patch, or correctly placing a long intraatrial suture can make the difference between a successful and an unsuccessful surgical outcome. The congenital heart surgeon is a student during his or her entire career because he or she encounters so many different anomalies. earning from the experience of others should always be part of the clinician s education; this is best done by personally observing an operation performed by another. Otherwise, the best record of a procedure is a good operative photograph. For over 35 years it has been my practice to photograph most operations.these illustrations comprise a valuable part of each patient s record and are informative as a review of previous surgery and observed anatomy if future surgery is planned. The illustrations also serve to inform the referring doctor of details of surgery and this may also improve patient care. The photographs have been an invaluable teaching aid for lectures, journal publications, and this book. I hope this atlas will be of interest to fulltime or part-time congenital heart surgeons, pediatric and adult cardiologists, intensivists, pediatricians, internists, and all other students of congenital heart disease. In this second edition, I have added many new sections, deleted a few obsolete sections, and in some areas changed the format. For example, the atrial switch operation has been moved to Chapter 16, l-transposition of the Great Arteries (l-tga). It is no longer used in the repair of d-transposition of the great arteries (d-tga), but is applicable for the double-switch operation for l-tga. Photographs were taken with a Nikon F camera, usually using a Nikon 55-mm macro lens (Figure P-1). For some close-up pictures of the right and left ventricular outflow tracts, a Nikon 100-mm medical lens was used (Figure P-2). Pictures were taken at f8 to f11 at a distance of 9 to 12 inches from the field. ighting for most photographs was augmented with a side-mounted Honeywell Strobonar flash with a wide-angle neutral density filter (Figures P-1, P-2). Using a side-mounted flash, rather than a more traditional ring light (surrounding the lens), has resulted in some shadows in each picture, which improves the perception of depth of field. More recently, I have used a ring light mounted on the front of the lens. No special effort has been made to use the operating room lights or to move them out of the field. ix

2 x Preface FIGUE P-1. Nikon camera viewer from above. A 5-mm macro lens is attached, and the light source is positioned to the side of the lens. A waist-level viewer is attached for taking pictures from the head of the operating table. FIGUE P-2. Nikon camera with 100-mm macro lens attached for close-up views. A sports viewer is used, and the position of the light source is at the side of the lens. Photographs were taken from behind the patient when surgery was performed through a lateral thoracotomy and from the head of the operating room table for a median sternotomy. For orientation, pictures in this atlas are marked with arrows to indicate, right side of patient;, left side of patient; Cep, alad; Caud, ad; Ant, anterior; and Post, posterior. S. Bert itwin, MD

3 14 Valvular Stenosis Valvular Stenosis unicuspid valve FIGUE This photograph shows severe valvular stenosis as it occurs in a newborn. There is a unicuspid, horseshoe-shaped leaflet with a single posterior commissure. eaflet tissue is thick, fibrous, and myxomatous. Successful valvotomy can be performed by creating a second commissure. Significant aortic regurgitation is rare due to the fibrous nature of the valve that prevents redundancy. Although typically there is residual stenosis after surgery, many infants will do surprisingly well for many years, even though the valve appears severely malformed and incompatible with life. This photograph was taken of a postmortem specimen in a child who died of other causes. 245

4 246 Color Atlas of Congenital Heart Surgery FIGUE For comparison, this postmortem specimen shows a normal aortic valve in another newborn infant. There are three cusps and each is thin and pliable. right coronary cusp stenotic commissures non coronary cusp left coronary cusp FIGUE In this older child with valvular stenosis, the exposure is through a proximal ascending aortotomy, with cardiopulmonary bypass, aortic cross-clamping, and cardioplegia. There are three leaflets that are fibrous and thickened with stenosis primarily of two commissures.

5 14 Valvular Stenosis 247 incised commissures FIGUE Valvotomy is performed by incising stenotic commissures. In some cases, the leaflets are thinned by resecting fibrous tissue Subaortic Stenosis: Fibromuscular Obstruction aortic valve FIGUE epair of this anomaly is performed with cardiopulmonary bypass and aortic clamping, cardioplegia, and profound local cardiac cooling, working through a proximal ascending aortotomy. Typically, the aortic valve is normal as seen here. There are three leaflets without commissural stenosis.

6 248 Color Atlas of Congenital Heart Surgery fibromuscular ledge FIGUE With retraction of the valve, a fibromuscular ledge is seen in the left lateral part of the outflow tract immediately below the valve annulus. stitch in obstructing muscle ledge FIGUE A stitch is placed in the middle of the ledge to facilitate grasping it while the resection is carried out.

7 14 Valvular Stenosis 249 rectangular wedge FIGUE A rectangular wedge of fibromuscular tissue is resected. It is safe to resect tissue as far anterior as the region beneath the middle of the right coronary cusp. The bundle of His pierces the ventricular septum beneath the noncoronary cusp, after which the bundle moves forward in the ventricular septum to the commissure between the noncoronary and right coronary cusps. Tissue is resected to the left and posteriorly as far as the base of the anterior mitral leaflet, which is located in the posterior wall of the left ventricular outflow tract. FIGUE The resected specimen is seen here.

8 250 Color Atlas of Congenital Heart Surgery fibrous collar FIGUE In another child, a typical fibrous collar is seen in the outflow tract immediately below the aortic valve annulus. area of resection FIGUE The fibrous collar has been resected along with a wedge of muscle.

9 14 Valvular Stenosis 251 aortic valve FIGUE In another patient, a normal aortic valve is seen. obstructing muscle ledge FIGUE The valve cusps are retracted and a fibromuscular obstruction is seen immediately below the annulus.

10 252 Color Atlas of Congenital Heart Surgery parallel incisions FIGUE A stitch is placed in the mid part of the ledge for retraction, and parallel incisions are made in the obstructing tissue. The rightward one is below the mid part of the right coronary cusp. muscle ledge to be resected FIGUE The obstructing muscle ledge is pulled into the field.

11 14 Valvular Stenosis 253 FIGUE The resected specimen is shown. The obstruction extended deep into the sinus portion of the left ventricle, and the long resected specimen depicts the length of the obstructive process. area of resection FIGUE The area of resection is wide to ensure relief of the obstruction.

12 254 Color Atlas of Congenital Heart Surgery Anomalous Mitral Valve Papillary Muscle anomalous papillary muscle extension into subaortic area fibrous extension into base of mitral leaflet aortic valve leaf FIGUE After placing another child on cardiopulmonary bypass, an opening is made in the proximal ascending aorta. A trileafed aortic valve is retracted, as is a narrow membrane located anteriorly. An obstructing muscle mass is exposed in the posterior left ventricular outflow tract. This is an anomalous extension of the mitral valve posterior medial papillary muscle with a fibrous tissue extension into the base of the anterior mitral leaflet. right coronary cusp anomalous papillary muscle extension fibrous attachment left coronary cusp FIGUE The fibrous membrane located beneath the right coronary cusp is excised and the anomalous muscle bundle is more easily seen.

13 14 Valvular Stenosis 255 papillary muscle excision mitral valve chords FIGUE The alad 25% of the posterior medial papillary muscle is excised. The lower portion of this papillary muscle is left intact and is attached to normal chords. The raw surface of the muscle excision is seen. papillary muscle excision FIGUE The raw surface of the excised muscle is again seen and normal mitral valve chords are identified. The lower 75% of the papillary muscle remains intact with these chords to provide mitral valve support. After closing the aorta and removing the child from bypass, there was no residual pressure gradient. mitral valve chords Modified Konno Procedure In some patients, the left ventricular outflow tract is narrow and local tissue resection alone is inadequate to relieve the obstruction. A modified Konno procedure can be used in this diverse group of patients, which includes tunnel-like stenosis, stenosis in patients after total repair of complete atrio-ventricular (AV) canal, and some cases of hypertrophic cardiomyopathy. The geometry of the outflow tract is altered by full thickness resection of the ventricular septum working through a right ventriculotomy and an aortotomy. The left ventricular outflow tract is further augmented by ventricular septal defect (VSD) patch closure, placing the patch on the right ventricular surface of the septum. If that patch encroaches on the right ventricular outflow tract, an additional patch can be placed in the ventriculotomy. When the right ventricular outflow tract is not compromised by the intracardiac patch, the repair can be performed working through an aortotomy and an adjacent right atriotomy.

14 256 Color Atlas of Congenital Heart Surgery right ventricle outflow tract aortic valve FIGUE The child has been placed on cardiopulmonary bypass and the proximal ascending aorta opened. A normal aortic valve is identified and severe long segment subaortic stenosis seen. ventriculotomy ventricular septum FIGUE A ventriculotomy is made in the region of the right ventricular outflow tract.

15 14 Valvular Stenosis 257 aortotomy tip of right angle clamp in VSD FIGUE An oblique incision is made in the ventricular septum starting immediately below the aortic valve and extending ad toward the patient s left side (starting at or to the left of corpora arantii of the right coronary cusp to avoid the His bundle). To identify this region, a right-angle clamp is passed through the aortic valve to protrude in the region of the septum to be incised. iatrogenic VSD FIGUE The large ventriculotomy is seen and through this region obstructing tissue in the left ventricle can be excised. If ventricular septal tissue is to be removed, this should be toward the patient s left in order to avoid the region of the bundle of His.

16 258 Color Atlas of Congenital Heart Surgery VSD FIGUE Multiple felted mattress sutures are placed around the right ventricular surface of the VSD. patch FIGUE A Dacron patch is used to close the VSD positioning the patch on the right ventricular surface of the septum.

17 14 Valvular Stenosis 259 FIGUE The right ventriculotomy is closed with a tissue patch to enlarge the right ventricular tract; the aortotomy has been closed. outflow tract patch Supravalvar Stenosis In the presence of this anomaly, there is usually a severe stenosing ring, at or immediately above the aortic valve commissures. A simple incision across the area of stenosis with patch angioplasty is often inadequate to relieve the obstruction. The stenosing ring must be incised into at least two sinuses of Valsalva. Three effective repair techniques are described. ascending aorta supravalvar stenosis FIGUE An external view of the heart shows the narrow proximal ascending aorta at the site of supravalvar stenosis.

18 260 Color Atlas of Congenital Heart Surgery supravalvar stenosing ring lower ends of inverted Y incision FIGUE After the cardiopulmonary bypass is established, with moderate hypothermia, aortic cross-clamping, cardioplegic arrest, and profound local cooling, an inverted Y incision is made in the ascending aorta. The stenosing supravalvar ring is seen. area of stenosing ring aortic valve lower ends of inverted Y incision FIGUE The lower ends of the inverted Y incision are extended into the sinuses of Valsalva of the noncoronary and right coronary cusps, respectively.

19 14 Valvular Stenosis 261 stenosing ring orifice of left coronary artery aortic valve cusp FIGUE The root of the aorta is exposed after completing the inverted Y incision. The stenosing supravalvar ring is immediately above the valve commissures. Normal valve leaflets are seen, and the orifice of the left coronary artery is located just beneath the ring. In some cases coronary stenosis occurs when fibrous tissue compromises the orifice. lower points of patch FIGUE A synthetic patch is tailored so that the lower points of the patch will fit in the opened sinuses of Valsalva.

20 262 Color Atlas of Congenital Heart Surgery area of commissure lower points of patch FIGUE The completed repair is seen after the patch is stitched in place with a continuous suture. supravalvar stenosis FIGUE In another baby who has been placed on cardiopulmonary bypass, the area of supravalvar stenosis is in the typical position at the sino tubular junction.

21 14 Valvular Stenosis 263 distal ascending aorta stenosing ring FIGUE The ascending aorta is divided at/or immediately above the stenosing ring. Care must be taken to avoid injury to the coronary artery orifices, which are below the ring. left coronary artery orifice sinus of Valsalva incisions right coronary artery orifice FIGUE Incisions are made in each of the three sinuses of Valsalva from the ring to near the annulus. The proximity of the coronary artery orifices is seen.

22 264 Color Atlas of Congenital Heart Surgery homograft patches aortic valve leaflets FIGUE Triangular-shaped tissue patches of homograft pulmonary wall are stitched over incisions in the left and right coronary cusp sinuses. The noncoronary cusp sinus remains open and a patch will be placed here to complete this part of the repair. homograft patch aortic anastomosis FIGUE A direct end-to end anastomosis is performed between the two aortic segments. Counter incisions in the upper aorta may be required due to the disparity in diameter of the two segments caused by adding the homograft patches.

23 14 Valvular Stenosis 265 supravalvar stenosis FIGUE In another infant, after establishing cardiopulmonary bypass with aortic clamping, cardioplegia, and profound local cooling, the supravalvar stenosis is seen at the sinotubular junction. stenosing ring FIGUE The ascending aorta has been widely dissected including the arch for mobility because the anastomosis will shorten the ascending aorta. Here, it is divided immediately above the stenotic ring. Care must be taken to avoid injury to the coronary arteries, which originate below the ring.

24 266 Color Atlas of Congenital Heart Surgery aortic valve FIGUE The ring is retracted to expose normal aortic valve leaflets and to view the coronary artery orifices. sinus of Valsalva incisions FIGUE Incisions are made from the ring into each sinus of Valsalva to near the aortic valve annulus.

25 14 Valvular Stenosis 267 incisions in distal aortic segment commissure FIGUE ongitudinal counter incisions are made in the upper aortic segment, each being opposite an aortic valve commissure. incision in distal aortic segment commissure FIGUE Each commissure will fit in an adjacent upper aortic longitudinal incision.

26 268 Color Atlas of Congenital Heart Surgery primary aortic anastomosis FIGUE A direct end-to-end anastomosis is performed between the two aortic segments. With such, the area of previous stenosis has been opened widely by the incisions into each aortic segment Aortic oot Enlargement Procedures Posterior oot Enlargement aortic valve cusps FIGUE With cardiopulmonary bypass, aortic clamping, and cardioplegia with profound local cardiac cooling, a proximal ascending aortotomy is made. A bicuspid stenotic and dysplastic valve is seen. After it is determined that valvuloplasty is not possible, the valve leaflets are excised.

27 14 Valvular Stenosis 269 anterior mitral leaflet extended aortotomy annulus FIGUE The aortotomy is extended ad and posteriorly through the valve annulus to the base of the anterior mitral leaflet. With this technique, the annulus can be enlarged by up to 4 to 5mm. treated pericardial patch FIGUE Glutaraldehyde-treated pericardium is stitched over the lower aortotomy extension.

28 270 Color Atlas of Congenital Heart Surgery pericardial patch FIGUE The pericardial patch is retracted anteriorly and seen from outside the aorta. prosthetic valve valve stitches in patch pericardial patch FIGUE A prosthetic valve is implanted at the level of the native aortic valve annulus, and the pericardial patch now comprises part of that annulus. To complete the repair, the remaining pericardial patch is stitched over the aortotomy.

29 14 Valvular Stenosis Konno Procedure with a Prosthetic Valve aortic valve cusps FIGUE The aortotomy is made in a longitudinal direction and to the left of the right coronary artery orifice. The severely scarred valve cusps are beyond repair, and it is decided to proceed with valve replacement and anterior root enlargement. aortotomy right ventriculotomy ventricular septum FIGUE An adjacent incision is made in the anterior wall of the right ventricular outflow tract to expose the septum.

30 272 Color Atlas of Congenital Heart Surgery valve leaflet ventricular septal incision FIGUE The aortic valve annulus is incised by working to the left of the right coronary orifice. The incision extends into the upper part of the ventricular septum alad to the His bundle. Valve leaflets are excised in preparation for valve replacement. patch in ventricular septal defect FIGUE A woven Dacron patch is tailored to conform to the iatrogenic VSD and adjacent aortotomy. The lower part of the patch is placed over the VSD with interrupted felted mattress sutures, placing the patch on the left ventricular surface of the septum.

31 14 Valvular Stenosis 273 native valve annulus ventricular septal defect patch FIGUE The patch is retracted anteriorly and interrupted valve sutures are placed in the native valve annulus. Additional anterior valve sutures pass through the patch. prosthetic valve FIGUE After the valve orifice is sized, an appropriate prosthetic valve is stitched in place in the subcoronary position. At least 60% of the valve annulus should be placed in the native annulus. Significant enlargement of the left ventricular outflow tract is accomplished, allowing for placement of a larger prosthesis.

32 274 Color Atlas of Congenital Heart Surgery annulus of valve patch over ventricular septal defect FIGUE The upper segment of the Dacron patch is stitched to the aortotomy with a continuous suture. Felt pledgets of valve sutures are seen and the repaired VSD is ad to the valve annulus. pericardial patch over right ventricular outflow area patch covering aortic wall patch FIGUE A pericardial patch is stitched over the right ventriculotomy and extends in continuity across the surface of the Dacron patch. Blood that leaks from the Dacron patch is collected beneath the pericardial patch and drains to the right ventricle.

33 Konno Procedure with a Homograft Valve 14 Valvular Stenosis 275 ascending aorta right coronary artery FIGUE The right coronary artery is in the usual anterior aortic root location. aortotomy to left of right coronary artery right ventriculotomy aortic valve cusps ventricular septal incision FIGUE A longitudinal incision in the proximal aorta is directed to the left of the right coronary artery orifice. An adjacent right ventriculotomy is made, and the aortic valve annulus is incised, extending this incision into the ventricular septum.

34 276 Color Atlas of Congenital Heart Surgery mitral leaflet of homograft patch homograft to native annulus stitch ventricular septal incision FIGUE Native aortic valve cusps are excised. An aortic valve homograft is tailored, leaving a large patch of homograft wall anteriorly. The homograft is positioned so that its mitral leaflet is located anteriorly. The homograft is stitched to the native valve annulus with a continuous monofilament suture, placing this stitch immediately below the homograft valve annulus. mitral leaflet of homograft ventricular septum FIGUE The homograft mitral leaflet is used to close the VSD with interrupted felted mattress sutures. These stitches are passed from the left ventricular surface of the septum and then through the adjacent homograft mitral leaflet. Pledgets are used on both surfaces of the septum.

35 14 Valvular Stenosis 277 aortotomy posterior homograft to native aorta suture anterior wall of homograft FIGUE Homograft aortic wall is removed from two posterior sinuses of Valsalva of the graft. The central homograft commissure is in the midline, and the upper rim of the homograft is stitched to the posterior wall of the native ascending aorta. anterior homograft wall to native aorta suture homograft mitral leaflet stitched to ventricular septum right ventriculotomy FIGUE The anterior homograft aortic wall is stitched to the aortotomy of the native aorta.

36 278 Color Atlas of Congenital Heart Surgery anterior wall of homograft stitched to native aorta harvested homograft patch in right ventricular outflow FIGUE A homograft aortic wall patch that was harvested in the tailoring process is used to reconstruct the right ventricular outflow tract. The homograft aortic wall patch covers the ventriculotomy and is stitched to the anterior homograft valve annulus oss Konno Procedure aortotomy autograft explant site in right ventricular outflow ventricular septal incision autograft FIGUE After establishing cardiopulmonary bypass with moderate hypothermia, aortic clamping, cardioplegic arrest, and profound local cooling, the pulmonary autograft is harvested. The main pulmonary artery has been divided proximal to the branches and the proximal vessel with the valve was harvested from the right ventricule. A circumferential 0.5-cm muscle bar was taken with the graft. Here, the ascending aorta has been opened in a longitudinal direction, extending this excision across the aortic valve annulus into the ventricular septum. This relieves the left ventricular outflow tract obstruction.

37 14 Valvular Stenosis 279 muscle ridge autograft leaflets FIGUE Prior to implantation, the autograft leaflets are inspected and found to be normal. annulus marking stitches explant site ventricular septal defect FIGUE Aortic valve leaflets are excised, leaving a 1-mm segment of leaflet attached to the native annulus. The new left ventricular outflow tract opening is marked with three trifurcating stitches. These are placed opposite the native sinuses of Valsalva and will be inserted near the middle of each autograft sinus of Valsalva.

38 280 Color Atlas of Congenital Heart Surgery autograft stitches for ventricular septal defect closure FIGUE The trifurcating stitches are placed in the proximal autograft muscle bar, opposite the mid part of each autograft leaflet. Multiple interrupted felted stitches are passed through the ventricular septum from left ventricle into right ventricle in preparation for closing the VSD. autograft anterior muscle bar VSD patch FIGUE A Dacron patch is placed over the VSD utilizing previously inserted stitches. The autograft will be attached to the native aortic valve annulus with multiple interrupted fine polypropylene sutures. In situ the graft fits well. The VSD patch will be attached to the anterior muscle bar with additional interrupted sutures.

39 14 Valvular Stenosis 281 native aorta autograft VSD patch right ventriculotomy FIGUE Working inside the native aorta, the posterior wall of the graft sinuses of Valsalva is tailored and then the graft is stitched to the posterior native aorta below and around the coronary orifices. The posterior graft commissure is also attached to the posterior native aorta. The anterior wall of the autograft is stitched to the opening in the native aorta. pulmonary homograft anterior muscle bar ventriculotomy FIGUE A pulmonary valve homograft with attached main pulmonary artery is used for reconstruction of the right ventricular outflow tract. Its muscle bar is stitched to the posterior right ventricle and the anterior graft muscle bar is stitched to the ventriculotomy.

40 282 Color Atlas of Congenital Heart Surgery Apical eft Ventricle to Ascending Aorta Conduit In small infants, when an apical aortic conduit is required, there may be inadequate space in which to work to attach the conduit to the descending aorta when working through a median sternotomy. Here the conduit is attached to the ascending aorta. main pulmonary artery ascending aorta FIGUE Through a median sternotomy, a small ascending aorta is seen. The procedure is performed with cardiopulmonary bypass, moderate hypothermia, aortic clamping, and cardioplegic arrest plus profound local cooling. left apical ventriculotomy FIGUE A left apical ventriculotomy is made, and a button of ventricular wall is removed.

41 14 Valvular Stenosis 283 conduit valve FIGUE A porcine-valved conduit (12 mm in this case) is beveled and stitched to the ventriculotomy with a continuous monofilament suture. The conduit valve is placed near the ventriculotomy. ascending aorta FIGUE A longitudinal ascending aortotomy is made to accept the distal end of the conduit.

42 284 Color Atlas of Congenital Heart Surgery FIGUE The completed aortic anastomosis is shown and the conduit lies along the left heart border.

43 7 Pulmonary Stenosis Pulmonary stenosis can occur at one or more sites from the proximal right ventricular outflow tract to the peripheral pulmonary arteries. Valvar obstruction and peripheral pulmonary stenosis are usually treated by closed balloon angioplasty; however, surgical repair is performed in many patients, especially those in whom operation is carried out for associated anomalies. Narrowing of the main pulmonary artery and/or the proximal right and left branches is most commonly associated with tetralogy of Fallot and will be discussed in Chapter Valvular Pulmonary Stenosis Pulmonary valvotomy is performed using cardiopulmonary bypass, including left ventricular venting and aortic cross-clamping; although in unusual circumstances, as in very small neonates, it is most expeditious to avoid the use of a left ventricular vent. In these cases, care must be taken not to allow air from the opened right heart to enter the left heart through an intracardiac communication as a patent foramen ovale. Aortic clamping may also be optional but its use helps in reducing blood flow from the coronary sinus into the right ventricle and the operative field. An alternative method to reduce blood flow into the operative field when not using aortic cross-clamping is the use of a single right atrial cannula that the drains coronary sinus as well as caval return. In this instance, the tricuspid valve must remain competent during bypass or otherwise excessive air will enter the venous return line to the pump. 129

44 130 Color Atlas of Congenital Heart Surgery leaflets FIGUE 7-1. After the cardiopulmonary bypass is established, the proximal main pulmonary artery is opened transversely or longitudinally. Three commissures of the trileafed pulmonary valve are stenotic, and there is mild thickening of the leaflets. incised commissures FIGUE 7-2. All commissures are incised to the annulus.

45 7 Pulmonary Stenosis 131 main pulmonary artery valve FIGUE 7-3. In this patient, after cardiopulmonary bypass is established, a proximal main pulmonary arteriotomy is made. There are three leaflets with stenotic commissures, and the valve is dysplastic. All leaflets are fibrous with limited mobility. Incising the stenotic commissures alone will not relieve the obstruction, because the leaflets are bulky and will not adequately move out of the stream of blood during systole. Part or all of the leaflets will be resected to avoid residual obstruction Infundibular Stenosis and Double Chamber ight Ventricle epair is performed with cardiopulmonary bypass, aortic clamping, cardioplegic arrest, and profound local cardiac cooling. septal band os infundibulum anterior wall extension of obstructing parietal band parietal band FIGUE 7-4. After the child is placed on cardiopulmonary bypass, a high right ventriculotomy is made. Obstruction at the os infundibulum is identified. There are large muscle ridges in the region of the parietal and septal bands extending to the anterior wall of the right ventricle. Fibrous tissue surrounds the os.

46 132 Color Atlas of Congenital Heart Surgery os infundibulum tricuspid valve papillary muscle FIGUE 7-5. Obstructing muscle and fibrous tissue has been resected, and the tricuspid apparatus below this area is seen. parietal band moderator band FIGUE 7-6. Double-chambered right ventricle is a form of infundibular pulmonary stenosis caused by muscle obstruction that is primarily in the area of the moderator band, as seen on this right ventriculogram.

47 7 Pulmonary Stenosis 133 parietal band moderator band tricuspid valve leaflets FIGUE 7-7. In this patient with double chamber right ventricle the exposure is through a right atriotomy while the tricuspid valve is retracted. The hypertrophied moderator band forms the major blockage, although an obstructing parietal band is also seen. parietal band VSD FIGUE 7-8. An associated membranous ventricular septal defect (VSD) is located medial to the parietal band.

48 134 Color Atlas of Congenital Heart Surgery os infundibulum VSD patch FIGUE 7-9. The parietal and moderator bands are resected, and the os infundibulum is now open. The VSD is closed with multiple interrupted mattress sutures and a Dacron patch.