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Transposition of the great vessels with ventricular septal defect
Transposition of the great vessels with ventricular septal defect Surgical and anatomic considerations Closure of a large ventricular septal defect (VSD) at the time of correction of transposition of the great vessels (TGV) by the Mustard technique presents certain technical problems. The study of the location of the VSD in 94 autopsied hearts with TGV and its relationship to the atrioventricular valves revealed that most of the defects can be closed through the tricuspid orifice rather than through a ventriculotomy. Our experience in 13 patients with TGV and a large VSD in a series of 72 Mustard operations performed since 1968 was reviewed. In 11 patients the VSD was closed through the tricuspid valve. In 2 patients, a large apical VSD was left open because of the presence of irreversible pulmonary vascular disease (Grade IV). One patient in this group died. These pathological and clinical observations revealed that the VSD's in TGV can be closed through the tricuspid valve without the need for a ventriculotomy, except for the apical muscular defects. For patients with severe pulmonary vascular disease, the Mustard procedure without closure of the VSD gives satisfactory results and palliation.
F. S. Idriss, M.D., Jose Aubert, M.D. (by invitation), Milton Paul, M.D. (by invitation), H. Nikaidoh, M.D. (by invitation), Maurice Lev, M.D. (by invitation), and E. A. Newfeld, M.D. (by invitation), Chicago, Ill.
Because of additional technical and hemodynamic considerations, surgical correction of transposition of the great vessels (TGV) becomes more complicated when associated with a ventricular septal defect (VSD) with or without pulmonary stenosis. The technical problems encountered with the closure of these defects are related to their size, location on the interventricular From the Divisions of Cardiovascular-Thoracic Surgery and Cardiology and the Department of Pathology, the Children's Memorial Hospital; the Departments of Surgery, Pediatrics, and Pathology, Northwestern University Medical School; and the Congenital Heart Disease Research and Training Center, Hektoen Institute for Medical Research, Chicago, Ill. Supported in part by the Griffin Grant for Heart Research and in part by Grant No. An-53 from the Chicago Heart Association. Address for reprints: F. S. Idriss, M.D., Children's Memorial Hospital, 2300 Children's Plaza, Chicago, Ill. 60614.
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septum, and position relative to the tricuspid, aortic, and pulmonary valves. In order to evaluate these problems we have studied a large number of autopsied hearts with TGV and VSD, noting particularly the surgical approach for the closure of the defects. The presence of a VSD may further complicate the management of TGV by the early development of pulmonary hypertension and pulmonary vascular disease, unless the pulmonary vascular bed is protected by the presence of pulmonary stenosis or by pulmonary artery banding performed in the first 6 months of life. 1 In a series of 72 Mustard operations performed at the Children's Memorial Hospital in Chicago, 11 patients had closure of the VSD; in 2 patients the VSD was left open
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TGV with VSD
733
Table I
Case No.
Age at operation
2 3*
3 yr. 2 mo. 12 mo. 17 mo.
4 5 6 7 8 9 10
11 12
13
Location and size of VSD
High, small Small Mid, large 22 mo. Apical, large 6 yr. 9 High, large mo. 19 mo. Apical, medium 11 yr. 5 Mid, large mo. 2 yr. 1 Subaortic, mo. larget 5 mo. High, medium 14 yr. High, subpulmonary artery, larget 17 yr. Mid, large 6 yr. Mid, large 6 yr., 10 High, mo. large
PSP, LVPA
MPAP
(mm.
(mm,
Hg)
Hg)
PVR (units)
Suture
85-16
12
N
No
Suture None SBV Banding ASD, PAB Suture
60-12 80-60
9 50
N 10.2
No Yes
IV
Yes No
75-70
55
6.8
Yes
IV
Yes
85-12
10
N
No
No
80-80
60
9
Yes
Suture
90-16
13
N
No
Patch
85-18
15
N
Yes
I
Yes
SBV, val- None vular None SPY
Suture
80-60
35
N
Yes
III
Yes
Patch
100-24
17
N
No
No
Valvular Baffes
Suture
95-16
12
N
No
No
Banding ASD, PAB Suture
85-22
16
N
Yes
I
No
110-14
10
N.
Yes
N
Yes
Location of PS
SBV
None
Previous operation
ASD
ASD
Closure of VSD
No
Banding ASD, PAB Patch None
ASD
SBV, val- Baffes vular SBV None
SBV, val- Right, vular SPS
Patch
Lung biopsy PVD
BAS
Yes
No IV
Yes No
Legend: VSD, Ventricular septal defect. PS, Pulmonary stenosis. PSP, Peak systolic pressure. LV-PA, Left ventriclepulmonary artery. MPAP, Mean pulmonary artery pressure. PVR, Pulmonary vascular resistance (units = millimeters of mercury per liter per minute per square meter). PVD, Pulmonary vascular disease (Heath-Edwards classification). BAS, Balloon atrial septostorny. SBV, Sub valvular. SPY, Suprava lvular. ASD, Surgical creation of atrial septal defect. PAB, Pulmonary artery banding. SPS, Subclavian-pulmonary shunt. Baffes, Baffes procedure. N designates 3 units or less. °This patient died on the first postoperative day. tThe ventricular septal defect was intracristal; the superior margin of the patch was sutured to the aorto-pulmonary septum.
because of the presence of severe pulmonary hypertension and advanced pulmonary vascular disease. This report concerns our surgical experience with this lesion in patients as well as an analysis of the surgical pathology of autopsied hearts. Material and methods
We studied 94 autopsied hearts with simple dextrotransposition of the great vessels (d-TGV) and VSD, generally unaltered
by surgery, which had been collected from the Children's Memorial Hospital and the Congenital Heart Disease Research and Training Center, Hektoen Institute for Medical Research, Chicago, Illinois. The location of the defects on the ventricular septum and their relationship to the atrioventricular and semilunar valves were noted. A defect whose edge was bordering or adjacent (within 2 mm. or less) to a valve was considered to be anatomically related to that valve, except when the rim of tissue
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Fig. 1. Case 6. Cineangiocardiogram of a large apical ventricular septal defect. RV, Right ventricle. LV, Left ventricle. PA, Pulmonary artery .
Fig. 2. Case 13. Large high ventricular septal defect as seen on the angiocardiogram.
separating the VSD from the semilunar valve was the cause of subvalvular stenosis. The most appropriate surgical exposure for closure of the defect, be it through the tricuspid valve or through a ventriculotomy, was evaluated. This autopsy analysis was completed before we began performing operations for closure of the defects in patients. More recently, and after our surgical experience, we reviewed again 86 autopsied hearts and mapped the location of their defects on the right side of the ventricular septum . The 13 patients with d-TGV and VSD who comprise this report were operated upon at the Children's Memorial Hospital in Chicago, Illinois, between 1971 and 1973. Their ages ranged from 5 months to 17 years and their weights from 4.5 to 55.4 kilograms. The type of VSD, associated lesions, previous surgical procedures, and other pertinent data are detailed in Table I. Most of the VSD's were below the crista or arch, two were apical muscular defects (Cases 4 and 6, Fig. 1), and two (Cases
8 and 10) were associated with excavated or absent crista (intracristal) with the upper rim of the defect being formed by the aortic-pulmonary septum. Seven patients underwent balloon atrial septostomy in infancy, 3 of whom required subsequent surgical creation of an atrial septal defect. Pulmonary artery banding had been performed in 3 patients. In 7 patients there was an associated significant pulmonary stenosis with a left ventricular-pulmonary artery gradient of over 50 mm. Hg. All the defects were exposed and repaired through the tricuspid valve after the aorta had been cross-clamped for 15 minute intervals, with intervening 5 minute periods of coronary perfusion. All the defects, except in 2 patients, were large (Fig. 2); however, it was possible to close seven by mattress sutures buttressed with Teflon pledgets, since the defects were more oval and slitlike than round and the edges could be easily approximated. In 4 patients an elastic Dacron patch was needed for the closure. In 2 patients (Cases 4 and 6) the VSD was left open because of the presence of severe pulmonary
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hypertension and advanced pulmonary vascular disease. Relief of pulmonary stenosis (subvalvular in 6 patients, 4 of whom had a fairly localized fibrous shelf) was performed retrograde through an incision in the pulmonary artery after placement of the intraatrial baffle and closure of the VSD. The use of the Killian nasal speculum for retraction, coupled with a short period of circulatory arrest in order to achieve a bloodless field, facilitated resection of the subvalvular stenosis. In Case lOa severe pressure gradient of 76 mm. Hg was caused by an unusual supravalvular narrowing. The operations were performed by means of a roller pump, a rotating disc, or a Bentley Temptrol oxygenator primed with a mixture of blood and Ringer's lactate in 5 per cent dextrose in water. The degree of hemodilution depended on the preoperative hematocrit value, except in infants weighing less than 10 kilograms, in whom whole blood was generally used. The flow rates averaged 2,500 c.c. per minute per square meter. The temperature of the patients was usually maintained at 30° C. except during resection of the pulmonary stenosis; at this point, the body temperature was lowered to 25° C. and circulatory arrest was used. A lung biopsy was performed in 7 patients either prior to or at the time of the intracardiac repair in order to assess the degree of pulmonary vascular disease. In some of the patients, the information obtained from these biopsies was used in conjunction with the cardiac catheterization data to decide whether or not to close the VSD. One patient (Case 9) had Grade III and 3 patients (Cases 3, 4, and 6) had Grade IV pulmonary vascular disease." Results and conclusions Tables II and III show the relationship of the VSD to the tricuspid, mitral, aortic, and pulmonary valves in 94 autopsied hearts. In sixteen of the specimens the defects were not adjacent to the tricuspid valve. Thus our initial conclusion derived from this study was that the VSD could be
Table II. Position of VSD in relation to tricuspid and mitral valves in 94 autopsied hearts Per cent
VSD
No.
Related to tricuspid valve Related to tricuspid and mitral valves Related to mitral valve Totals
61/94
65
18/94 2/94 81/94
19.2 2.1 86.3
Legend: A ventricular septal defect (VSD) is considered anatomically related to a valve when its edge is situated less than 2 mm. from the valve.
Table III. Position of VSD in relation to aortic and pulmonary valves in 94 autopsied hearts VSD
Related to aortic valve only Related to pulmonary valve and aortic valve Related to pulmonary valve only Totals
No.
Per cent
8/94
8.5
3/94
3.2
30/94 41/94
32 43.5
Legend: A ventricular septal defect (VSD) is considered related to a valve when its edge is situated less than 2 mm. from the valve.
exposed and closed through the tricuspid valve in most of the cases. In our clinical experience, we did not have to perform a ventriculotomy in any patient. The uncommon apical muscular VSD, present in two of the 94 autopsied hearts and in 2 of our 13 patients, would have been technically difficult if not impossible to visualize adequately from the right side of the septum through the tricuspid valve; however, as stated earlier, these two VSD's were left open because of the presence of advanced pulmonary vascular disease (Grade IV). Exposure of the high subaortic, subpulmonary (Fig. 3), and anterior muscular defects was more difficult than exposure of those nearer to the tricuspid valve. However, we found that waiting until the heart relaxed after aortic cross-clamping, then placing the first interrupted sutures on the upper rim of the defect, and using these
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The Journal of Thoracic and Cardiovascular Surgery
Fig. 5. Absent arch or excavated crista with a subaortic ventricular septal defect (V). For other abbreviations see Fig. 4. Fig. 3. Case 10. Subpulmonary ventricular septal defect (arrow).
Ao
Fig. 4. Diagram illustrates the distribution of ventricular septal defects in 86 autopsied hearts as seen from the right side of the septum. Ao , Aorta. Arch, Crista. PB, Parietal band . SB, Septal band. TV, Tricuspid valve orifice. CS, Coronary sinus orifice. MB, Moderator band . The stars represent multiple ventricular septal defects.
for traction were most helpful in bringing the VSD into view. The exposure was also improved by traction sutures placed on the septal and anterior leaflets of the tricuspid valve and by good illumination from a flexible fiberoptic light. Our findings on the location of the VSD in TGV as seen from the right side of the septum in 86 autopsied hearts are summarized in Fig. 4. The defects seemed to fall into four major groups. Group I (15 per cent). These are the defects which penetrated or excavated the crista or arch (intracristal). In eight of the specimens the upper rim of the VSD was immediately adjacent to the aortic valves (Fig. 5), and in five the defects were slightly lower and were separated from the aortic annulus by a narrow muscle band. Group II (56 per cent). These defects were the most frequently encountered and were situated under the arch or crista (Fig. 6). Some were closer to the tricuspid valve and others were more anteriorly situated.
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November, J 974
Fig. 6. Ventricular septal defect under the arch or crista ( A r). For other abbreviation s see Fig. 4.
This group includes the less common type of transposition described by Lev and associates, ~ in which the arch is formed by parietal bands only, rather than by the junction of the septal and parietal bands. There was one unusual specimen in which a slitlike VSD extended to the anterior ventricular wall across the septal bands (Fig. 7). Group III (26.7 per cent). This group included 23 midmuscular defects located posteriorly near the tricuspid valve, centrally, or anteriorly through or above the septal band (Fig. 8). Group IV (2.3 per cent). Group IV included apical muscular defects, which were the least common. Multiple defects, encountered in only two specimens, are represented by stars in Fig. 4. One hospital death occurred in the surgical series for an over-all mortality rate of 7.6 per cent. This patient , who died at the age of 1 year 5 months, was first seen at the Children's Memorial Hospital when he was 9 months of age. Cardiac catheterization revealed d-TGV with VSD and pulmonary hypertension. The left and right ventricular pressures were equal (90 mm. Hg peak systolic) , peak systolic pressure of the main pulmonary artery was 80 mm. Hg, and the calculated pulmonary vascular resistance was 8 units (units = millimeters of mercury per liter per minute per square
Fig. that wall Fig .
7. Unusual slitlike ventricular septal defect extends from under the arch to the anterior of the right ventricle. For abbreviations, see 4.
Fig . 8. Moderate-sized anterior muscular ventricular septal defect situated above the septal band (Sb). For other abbreviations see Fig. 4.
meter). Atrial septostomy and pulmonary artery banding were performed. Repeat cardiac catheterization when the boy was 15 months of age again revealed severe pulmonary hypertension and an elevated pulmonary vascular resistance of 10.2 units. A Mustard procedure with closure of the VSD was then performed when he was 17 months of age. The patient died on the first post-
The Journal of
738
Thoracic and Cardiovascular
Idriss et al.
Surgery
~
!
50
(J)(X)
4
:I:
!;(
!!!
3
• - vso & PS (CATH)
0
> "-
40
~=v:~~PS::(PATH)
0
30~
2
w
•
0
« ""o
•
N 4
12
MONTHS
•
•
E "Z
«
20 ~
••
6
4
:f
•
• 8
10
12
14
16
10 18
Y~ARS
AGE AT SURGERY
Fig. 9. Pulmonary vascular disease (PVD) in 13 operated patients. Path, Patients that had lung biopsies. Cath, Data obtained from cardiac catheterizations only, without lung biopsies. VSD, Ventricular septal defect. PS, Pulmonary stenosis, PAP, Pulmonary artery pressure.
operative day, presumably as a result of irreversible pulmonary vascular disease (Grades IV and V at autopsy) and not from causes directly related to the technical aspects of the operative procedure. Obviously and in retrospect, the VSD should not have been closed. Subsequently 2 patients (Cases 4 and 6) with severe pulmonary hypertension and pulmonary vascular disease (Grade IV) were operated upon, and only a palliative Mustard procedure was done, as suggested by Lindesmith and associates! Both patients are living and doing well. Discusion
The Mustard" procedure, which culminated the earlier efforts by Albert," Senning," Merendino," and Shumacker,? is presently the procedure of choice for the correction of simple TGV with intact ventricular septum, with good results and low mortality rates. We have used this procedure since 1968 and have accomplished an over-all adjusted hospital mortality rate of 3.8 per cent in a series of 52 patients operated upon between 1970 and 1973; this series includes several patients with complex transposition and several infants. 10 When a VSD is present, the mangement of the patient and the operative procedure may become more complicated. Very small insignificant defects can be left open. How-
ever, if the defect is hemodynamically significant, and especially if the defect is not associated with an effective pulmonary stenosis, early surgical intervention is needed. In a study of 200 lung specimens from patients with TGV, Newfeld and his co-workers 1 showed that large VSD's uniformly caused significant pulmonary vascular disease early in life; they concluded that surgical intervention to protect the pulmonary vascular bed should be undertaken within the first 6 months of life. Our clinical experience in Case 3 (indicated by an open circle with a cross in Fig. 9) showed that pulmonary artery banding in a 9-month-old child was ineffective because severe pulmonary vascular disease had already developed. Of 3 patients (open circles, Fig. 9) who did not have any protection to the lung, 2 (Cases 4 and 6) had Grade IV irreversible damage at 22 and 19 months of age and 1 (Case 9) had Grade III at 5 months of age; in contrast, the patients with VSD and pulmonary stenosis (triangles and dark circles) did not develop any significant pulmonary vascular disease, even at an older age. The question as to whether early surgical intervention should be closure of the VSD or pulmonary artery banding followed by later correction is not yet fully answered. Some centers report performing the correction in early infancy while others prefer the
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palliative procedure first, followed by repair at an older ageY-17 Carpena and Subramanian," in an analysis of 44 operations on patients with TGV and VSD, concluded that primary definitive repair in early infancy carried a higher mortality rate (33 per cent) than did early banding followed by early debanding and primary correction later in the first year of life (no deaths). The question of which approach to use cannot be settled until a large group of patients has been operated upon and until the combined mortality, morbidity, and late results of banding and debanding are compared with those of early primary correction. It appears to us that later repair of the VSD, when the heart is larger, would be technically easier to perform through the tricuspid valve; this approach avoids the need of an incision in the systemic ventricle. In the patients who have a VSD associated with subvalvular stenosis, it would be technically more advantageous to wait until an older age for management of the stenosis, particularly if it is of the type that may require a Rastelli" procedure. We have not used the Rastelli procedure in cases of VSD associated with subvalvular stenosis, even though in 2 patients the narrowing was rather diffuse and long. Our results are satisfactory at present; none of the patients has died. However, postoperative cardiac catheterizations have not yet been performed to assess the effectiveness of the valvular resection. Certainly, as noted by Trusler and Mustard," the surgeon should be ready to perform a Rastelli procedure whenever he encounters a long subvalvular narrow tunnel that cannot be widened. Our autopsy studies and clinical experience indicate that almost all VSD's in simple transposition can be surgically approached through the tricuspid valve orifice. During the operation, with the heart relaxed and with the aid of traction sutures on the rim of the defect, all locations on the ventricular septum except the apical portion can be reached. The uncommon apical
muscular VSD is difficult to repair from the right side of the septum either through the tricuspid valve or via a right ventriculotomy. Although closure could be accomplished by compression of the septum by sutures placed through the apex of the heart or directly through a left ventriculotomy, the apical defects appear to be better visualized from the left side of the septum. Furthermore, an incision in the pulmonary ventricle is not functionally as significant as an incision in the systemic right ventricle. REFERENCES Newfeld, E., Paul, M. H., Muster, A. J., and Idriss, F. S.: Pulmonary Vascular Disease in Complete Transposition of the Great Arteries: Study of 200 Patients, Am. J. Cardiol, 34: 75, 1974. 2 Heath, D., and Edwards, J. E.: The Pathology of Hypertensive Pulmonary Vascular Disease: A Description of Six Grades of Structural Changes in the Pulmonary Arteries With Special Reference to Congenital Cardiac Septal Defects, Circulation 18: 533, 1958. 3 Lev, M., Rimoldi, H. J. A., Eckner, F. A. 0., Melhuish, B. P., Meng, L., and Paul, M. H.: The Taussig-Bing Heart, Arch. Pathol. 81: 24, 1966. 4 Lindesmith, G. G., Stiles, Q. R., Tucker, B. L., Gallaher, M. E., Stanton, R. E., and Meyer, B. W.: The Mustard Operation as a Palliative Procedure, J. THoRAe. CARDIOVASC. SURG. 63: 75, 1972. 5 Mustard, W. T.: Successful Two-Stage Correction of Transposition of the Great Vessels, Surgery 55: 469, 1964. 6 Albert, H. M.: Surgical Correction of Transposition of the Great Vessels, Surg. Forum 5: 74, 1954. 7 Senning, A.: Surgical Correction of Transposition of the Great Vessels, Surgery 45: 966, 1959. 8 Merendino, K. A, Jesseph, 1. E., Herron, P. W., Thomas, G. I., and Vetto, R. R.: Interatrial Venous Transposition: A One-Stage Intracardiac Operation for the Conversion of Complete Transposition of the Aorta and Pulmonary Artery to Corrected Transposition. Theory and Clinical Experience, Surgery 42: 898, 1957. 9 Shumacker, H. B, Jr.: A New Operation for Transposition of the Great Vessels, Surgery 50: 773, 1961. 10 Idriss, F. S., Koopot, R., Paul, M. H., Nikaidoh, H., Riker, W. L., and Muster, A. J.: Transposition of the Great Arteries (TGA):
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Evolution of Surgical Technic in 60 Cases, Read at the forty-second Annual Meeting of the American Academy of Pediatrics, Cardiology Section, Chicago, Illinois, October 2024, 1973. 11 Bonchek, L. I., and Starr, A.: Total Correction of Transposition of the Great Arteries in Infancy as Initial Surgical Management, Ann. Thorac. Surg. 14: 376, 1972. 12 Subramanian, S., and Wagner, H.: Correction of Transposition of the Great Arteries in Infants Under Surface-Induced Deep Hypothermia, Ann. Thorac. Surg. 16: 391, 1973. 13 Clarkson, P. M., Barratt-Boyes, B. G., Neutze, J. M., and Lowe, J. B.: Results Over a TenYear Period of Palliation Followed by Corrective Surgery for Complete Transposition of the Great Arteries, Circulation 45: 1251, 1972. 14 Kilman, J. W., Williams, T. E., Jr., Kakos, G. S., Craenen, 1., and Hosier, D. M.: Surgical Correction of the Transposition Complex in Infancy, J. Thorac. Cardiovasc. Surg. 66: 387, 1973. 15 Danielson, G. K., Mair, D. D., Ongley, P. A., Wallace, R. B., and McGoon, D. C.: Repair of Transposition of the Great Arteries by Transposition of Venous Return, J. THORAC. CARDIOVASC. SURG. 61: 96, 1971. 16 Trusler, G. A., and Mustard, W. T.: Palliative and Reparative Procedures for Transposition of the Great Arteries, Ann. Thorac. Surg. 17: 410, 1974. 17 Breckenridge, I. M., Oelert, H., Stark, 1., Graham, G. R., Bonham-Carter, R. E., and Waterston, D. J.: Mustard's Operation for Transposition of the Great Arteries: Review of 200 Cases, Lancet 1: 1140, 1972. 18 Carpena, c., and Subramanian, S.: Management of the Ventricular Septal Defect in Transposition (Abstr.) , Am. J. Cardio\. 33: 130, 1973. 19 Rastelli, G. C., McGoon, D. C., and Wallace, R. B.: Anatomic Correction of Transposition of the Great Arteries With Ventricular Septal Defect and Sub pulmonary Stenosis, J. THORAC. CARDIOVASC. SURG. 58: 545, 1969.
Discussion DR. RANDALL GRIEPP Palo Alto, Calif.
I should like to congratulate the authors on a very impressive surgical series. At the Stanford University Hospital, 26 patients with TGV and large, nonrestrictive VSD's have undergone operative correction. Seventeen patients underwent VSD closure and intra-atrial baffling via the Mustard technique, In 13 patients
the VSD was closed via a right ventriculotomy. Six of these patients died, for an operative mortality rate of 46 per cent. Four patients underwent closure of the VSD through the tricuspid valve. All of these patients survived. Thus this portion of the experience supports the authors' contention that the preferred approach for VSD closure is through the right atrium. However, the late results in both the patients who underwent ventriculotomy and in those who did not have not been satisfactory. The majority of the patients required digitalis and diuretics to prevent fluid accumulation, and most have moderate-to-marked exercise intolerance. In 9 patients in our series, this combination of defects was corrected by means of the Rastelli technique. Via a right ventriculotomy, a Teflon patch was placed encompassing the VSD and the aortic valve. The pulmonary artery was detached from the left ventricle and the proximal end was closed. A Dacron tube graft was anastomosed between the right ventriculotomy and the distal pulmonary artery. In 3 patients a porcine heterograft valve was included in the graft. All of these patients survived the operation. In 6 patients no valve was utilized within the conduit, and 3 of them died. However, all 6 patients who survived surgery have had extremely satisfactory late results as measured by exercise tolerance and need for digitalis and diuretic therapy. On the basis of this experience, our present approach to the large VSD and transposition is as follows. The right atrium is opened, and the feasibility of baffling the left ventricular outflow through the aortic valve is assessed by direct observation of the VSD and palpation of the crista supraventricularis. If it is felt that a Rastelli procedure is possible, a ventriculotomy is made and the Rastelli operation is carried out with a valve conduit. If it is decided that a Rastelli procedure is not feasible, owing to a small VSD that cannot be practically enlarged, a prominent crista supraventricularis, or excessive distance between a VSD and the aortic valve, then the VSD is closed through the tricuspid valve and a Mustard procedure is then carried out. DR. IDRISS (Closing) First, we cannot discuss the Rastelli procedure with experience, because we have not performed the technique. The subvalvular pulmonary stenosis encountered in these patients was rather severe in 6 cases. In 4, the stenosis was discrete, and the resection was not very difficult. We were able to take a wedge out of the area. In 2 patients, the stenosis was a somewhat longer fibromuscular
Volume 68 Number 5
TGV with VSD
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November, 1974
tunnel, and again we were able to resect it. Of course, the ultimate result cannot be assessed until postoperative catheterization has been done and the results assessed. At this time, all we can say is that those patients are alive. Dr. Griepp, the question of performing a Ras-
telli in some of these patients should be viewed in relation to our pathology study. This study showed that most of the VSD's are below the crista; the crista is quite wide, so that in most patients a Rastelli type of procedure may be difficult to accomplish.
F. S. Idriss, M.D., Jose Aubert, M.D. (by invitation), Milton Paul, M.D. (by invitation), H. Nikaidoh, M.D. (by invitation), Maurice Lev, M.D. (by invitation), and E. A. Newfeld, M.D. (by invitation), Chicago, Ill.
Because of additional technical and hemodynamic considerations, surgical correction of transposition of the great vessels (TGV) becomes more complicated when associated with a ventricular septal defect (VSD) with or without pulmonary stenosis. The technical problems encountered with the closure of these defects are related to their size, location on the interventricular From the Divisions of Cardiovascular-Thoracic Surgery and Cardiology and the Department of Pathology, the Children's Memorial Hospital; the Departments of Surgery, Pediatrics, and Pathology, Northwestern University Medical School; and the Congenital Heart Disease Research and Training Center, Hektoen Institute for Medical Research, Chicago, Ill. Supported in part by the Griffin Grant for Heart Research and in part by Grant No. An-53 from the Chicago Heart Association. Address for reprints: F. S. Idriss, M.D., Children's Memorial Hospital, 2300 Children's Plaza, Chicago, Ill. 60614.
732
septum, and position relative to the tricuspid, aortic, and pulmonary valves. In order to evaluate these problems we have studied a large number of autopsied hearts with TGV and VSD, noting particularly the surgical approach for the closure of the defects. The presence of a VSD may further complicate the management of TGV by the early development of pulmonary hypertension and pulmonary vascular disease, unless the pulmonary vascular bed is protected by the presence of pulmonary stenosis or by pulmonary artery banding performed in the first 6 months of life. 1 In a series of 72 Mustard operations performed at the Children's Memorial Hospital in Chicago, 11 patients had closure of the VSD; in 2 patients the VSD was left open
Volume 68 Number 5 November, 1974
TGV with VSD
733
Table I
Case No.
Age at operation
2 3*
3 yr. 2 mo. 12 mo. 17 mo.
4 5 6 7 8 9 10
11 12
13
Location and size of VSD
High, small Small Mid, large 22 mo. Apical, large 6 yr. 9 High, large mo. 19 mo. Apical, medium 11 yr. 5 Mid, large mo. 2 yr. 1 Subaortic, mo. larget 5 mo. High, medium 14 yr. High, subpulmonary artery, larget 17 yr. Mid, large 6 yr. Mid, large 6 yr., 10 High, mo. large
PSP, LVPA
MPAP
(mm.
(mm,
Hg)
Hg)
PVR (units)
Suture
85-16
12
N
No
Suture None SBV Banding ASD, PAB Suture
60-12 80-60
9 50
N 10.2
No Yes
IV
Yes No
75-70
55
6.8
Yes
IV
Yes
85-12
10
N
No
No
80-80
60
9
Yes
Suture
90-16
13
N
No
Patch
85-18
15
N
Yes
I
Yes
SBV, val- None vular None SPY
Suture
80-60
35
N
Yes
III
Yes
Patch
100-24
17
N
No
No
Valvular Baffes
Suture
95-16
12
N
No
No
Banding ASD, PAB Suture
85-22
16
N
Yes
I
No
110-14
10
N.
Yes
N
Yes
Location of PS
SBV
None
Previous operation
ASD
ASD
Closure of VSD
No
Banding ASD, PAB Patch None
ASD
SBV, val- Baffes vular SBV None
SBV, val- Right, vular SPS
Patch
Lung biopsy PVD
BAS
Yes
No IV
Yes No
Legend: VSD, Ventricular septal defect. PS, Pulmonary stenosis. PSP, Peak systolic pressure. LV-PA, Left ventriclepulmonary artery. MPAP, Mean pulmonary artery pressure. PVR, Pulmonary vascular resistance (units = millimeters of mercury per liter per minute per square meter). PVD, Pulmonary vascular disease (Heath-Edwards classification). BAS, Balloon atrial septostorny. SBV, Sub valvular. SPY, Suprava lvular. ASD, Surgical creation of atrial septal defect. PAB, Pulmonary artery banding. SPS, Subclavian-pulmonary shunt. Baffes, Baffes procedure. N designates 3 units or less. °This patient died on the first postoperative day. tThe ventricular septal defect was intracristal; the superior margin of the patch was sutured to the aorto-pulmonary septum.
because of the presence of severe pulmonary hypertension and advanced pulmonary vascular disease. This report concerns our surgical experience with this lesion in patients as well as an analysis of the surgical pathology of autopsied hearts. Material and methods
We studied 94 autopsied hearts with simple dextrotransposition of the great vessels (d-TGV) and VSD, generally unaltered
by surgery, which had been collected from the Children's Memorial Hospital and the Congenital Heart Disease Research and Training Center, Hektoen Institute for Medical Research, Chicago, Illinois. The location of the defects on the ventricular septum and their relationship to the atrioventricular and semilunar valves were noted. A defect whose edge was bordering or adjacent (within 2 mm. or less) to a valve was considered to be anatomically related to that valve, except when the rim of tissue
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Fig. 1. Case 6. Cineangiocardiogram of a large apical ventricular septal defect. RV, Right ventricle. LV, Left ventricle. PA, Pulmonary artery .
Fig. 2. Case 13. Large high ventricular septal defect as seen on the angiocardiogram.
separating the VSD from the semilunar valve was the cause of subvalvular stenosis. The most appropriate surgical exposure for closure of the defect, be it through the tricuspid valve or through a ventriculotomy, was evaluated. This autopsy analysis was completed before we began performing operations for closure of the defects in patients. More recently, and after our surgical experience, we reviewed again 86 autopsied hearts and mapped the location of their defects on the right side of the ventricular septum . The 13 patients with d-TGV and VSD who comprise this report were operated upon at the Children's Memorial Hospital in Chicago, Illinois, between 1971 and 1973. Their ages ranged from 5 months to 17 years and their weights from 4.5 to 55.4 kilograms. The type of VSD, associated lesions, previous surgical procedures, and other pertinent data are detailed in Table I. Most of the VSD's were below the crista or arch, two were apical muscular defects (Cases 4 and 6, Fig. 1), and two (Cases
8 and 10) were associated with excavated or absent crista (intracristal) with the upper rim of the defect being formed by the aortic-pulmonary septum. Seven patients underwent balloon atrial septostomy in infancy, 3 of whom required subsequent surgical creation of an atrial septal defect. Pulmonary artery banding had been performed in 3 patients. In 7 patients there was an associated significant pulmonary stenosis with a left ventricular-pulmonary artery gradient of over 50 mm. Hg. All the defects were exposed and repaired through the tricuspid valve after the aorta had been cross-clamped for 15 minute intervals, with intervening 5 minute periods of coronary perfusion. All the defects, except in 2 patients, were large (Fig. 2); however, it was possible to close seven by mattress sutures buttressed with Teflon pledgets, since the defects were more oval and slitlike than round and the edges could be easily approximated. In 4 patients an elastic Dacron patch was needed for the closure. In 2 patients (Cases 4 and 6) the VSD was left open because of the presence of severe pulmonary
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hypertension and advanced pulmonary vascular disease. Relief of pulmonary stenosis (subvalvular in 6 patients, 4 of whom had a fairly localized fibrous shelf) was performed retrograde through an incision in the pulmonary artery after placement of the intraatrial baffle and closure of the VSD. The use of the Killian nasal speculum for retraction, coupled with a short period of circulatory arrest in order to achieve a bloodless field, facilitated resection of the subvalvular stenosis. In Case lOa severe pressure gradient of 76 mm. Hg was caused by an unusual supravalvular narrowing. The operations were performed by means of a roller pump, a rotating disc, or a Bentley Temptrol oxygenator primed with a mixture of blood and Ringer's lactate in 5 per cent dextrose in water. The degree of hemodilution depended on the preoperative hematocrit value, except in infants weighing less than 10 kilograms, in whom whole blood was generally used. The flow rates averaged 2,500 c.c. per minute per square meter. The temperature of the patients was usually maintained at 30° C. except during resection of the pulmonary stenosis; at this point, the body temperature was lowered to 25° C. and circulatory arrest was used. A lung biopsy was performed in 7 patients either prior to or at the time of the intracardiac repair in order to assess the degree of pulmonary vascular disease. In some of the patients, the information obtained from these biopsies was used in conjunction with the cardiac catheterization data to decide whether or not to close the VSD. One patient (Case 9) had Grade III and 3 patients (Cases 3, 4, and 6) had Grade IV pulmonary vascular disease." Results and conclusions Tables II and III show the relationship of the VSD to the tricuspid, mitral, aortic, and pulmonary valves in 94 autopsied hearts. In sixteen of the specimens the defects were not adjacent to the tricuspid valve. Thus our initial conclusion derived from this study was that the VSD could be
Table II. Position of VSD in relation to tricuspid and mitral valves in 94 autopsied hearts Per cent
VSD
No.
Related to tricuspid valve Related to tricuspid and mitral valves Related to mitral valve Totals
61/94
65
18/94 2/94 81/94
19.2 2.1 86.3
Legend: A ventricular septal defect (VSD) is considered anatomically related to a valve when its edge is situated less than 2 mm. from the valve.
Table III. Position of VSD in relation to aortic and pulmonary valves in 94 autopsied hearts VSD
Related to aortic valve only Related to pulmonary valve and aortic valve Related to pulmonary valve only Totals
No.
Per cent
8/94
8.5
3/94
3.2
30/94 41/94
32 43.5
Legend: A ventricular septal defect (VSD) is considered related to a valve when its edge is situated less than 2 mm. from the valve.
exposed and closed through the tricuspid valve in most of the cases. In our clinical experience, we did not have to perform a ventriculotomy in any patient. The uncommon apical muscular VSD, present in two of the 94 autopsied hearts and in 2 of our 13 patients, would have been technically difficult if not impossible to visualize adequately from the right side of the septum through the tricuspid valve; however, as stated earlier, these two VSD's were left open because of the presence of advanced pulmonary vascular disease (Grade IV). Exposure of the high subaortic, subpulmonary (Fig. 3), and anterior muscular defects was more difficult than exposure of those nearer to the tricuspid valve. However, we found that waiting until the heart relaxed after aortic cross-clamping, then placing the first interrupted sutures on the upper rim of the defect, and using these
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Fig. 5. Absent arch or excavated crista with a subaortic ventricular septal defect (V). For other abbreviations see Fig. 4. Fig. 3. Case 10. Subpulmonary ventricular septal defect (arrow).
Ao
Fig. 4. Diagram illustrates the distribution of ventricular septal defects in 86 autopsied hearts as seen from the right side of the septum. Ao , Aorta. Arch, Crista. PB, Parietal band . SB, Septal band. TV, Tricuspid valve orifice. CS, Coronary sinus orifice. MB, Moderator band . The stars represent multiple ventricular septal defects.
for traction were most helpful in bringing the VSD into view. The exposure was also improved by traction sutures placed on the septal and anterior leaflets of the tricuspid valve and by good illumination from a flexible fiberoptic light. Our findings on the location of the VSD in TGV as seen from the right side of the septum in 86 autopsied hearts are summarized in Fig. 4. The defects seemed to fall into four major groups. Group I (15 per cent). These are the defects which penetrated or excavated the crista or arch (intracristal). In eight of the specimens the upper rim of the VSD was immediately adjacent to the aortic valves (Fig. 5), and in five the defects were slightly lower and were separated from the aortic annulus by a narrow muscle band. Group II (56 per cent). These defects were the most frequently encountered and were situated under the arch or crista (Fig. 6). Some were closer to the tricuspid valve and others were more anteriorly situated.
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Fig. 6. Ventricular septal defect under the arch or crista ( A r). For other abbreviation s see Fig. 4.
This group includes the less common type of transposition described by Lev and associates, ~ in which the arch is formed by parietal bands only, rather than by the junction of the septal and parietal bands. There was one unusual specimen in which a slitlike VSD extended to the anterior ventricular wall across the septal bands (Fig. 7). Group III (26.7 per cent). This group included 23 midmuscular defects located posteriorly near the tricuspid valve, centrally, or anteriorly through or above the septal band (Fig. 8). Group IV (2.3 per cent). Group IV included apical muscular defects, which were the least common. Multiple defects, encountered in only two specimens, are represented by stars in Fig. 4. One hospital death occurred in the surgical series for an over-all mortality rate of 7.6 per cent. This patient , who died at the age of 1 year 5 months, was first seen at the Children's Memorial Hospital when he was 9 months of age. Cardiac catheterization revealed d-TGV with VSD and pulmonary hypertension. The left and right ventricular pressures were equal (90 mm. Hg peak systolic) , peak systolic pressure of the main pulmonary artery was 80 mm. Hg, and the calculated pulmonary vascular resistance was 8 units (units = millimeters of mercury per liter per minute per square
Fig. that wall Fig .
7. Unusual slitlike ventricular septal defect extends from under the arch to the anterior of the right ventricle. For abbreviations, see 4.
Fig . 8. Moderate-sized anterior muscular ventricular septal defect situated above the septal band (Sb). For other abbreviations see Fig. 4.
meter). Atrial septostomy and pulmonary artery banding were performed. Repeat cardiac catheterization when the boy was 15 months of age again revealed severe pulmonary hypertension and an elevated pulmonary vascular resistance of 10.2 units. A Mustard procedure with closure of the VSD was then performed when he was 17 months of age. The patient died on the first post-
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Idriss et al.
Surgery
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~=v:~~PS::(PATH)
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••
6
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:f
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Fig. 9. Pulmonary vascular disease (PVD) in 13 operated patients. Path, Patients that had lung biopsies. Cath, Data obtained from cardiac catheterizations only, without lung biopsies. VSD, Ventricular septal defect. PS, Pulmonary stenosis, PAP, Pulmonary artery pressure.
operative day, presumably as a result of irreversible pulmonary vascular disease (Grades IV and V at autopsy) and not from causes directly related to the technical aspects of the operative procedure. Obviously and in retrospect, the VSD should not have been closed. Subsequently 2 patients (Cases 4 and 6) with severe pulmonary hypertension and pulmonary vascular disease (Grade IV) were operated upon, and only a palliative Mustard procedure was done, as suggested by Lindesmith and associates! Both patients are living and doing well. Discusion
The Mustard" procedure, which culminated the earlier efforts by Albert," Senning," Merendino," and Shumacker,? is presently the procedure of choice for the correction of simple TGV with intact ventricular septum, with good results and low mortality rates. We have used this procedure since 1968 and have accomplished an over-all adjusted hospital mortality rate of 3.8 per cent in a series of 52 patients operated upon between 1970 and 1973; this series includes several patients with complex transposition and several infants. 10 When a VSD is present, the mangement of the patient and the operative procedure may become more complicated. Very small insignificant defects can be left open. How-
ever, if the defect is hemodynamically significant, and especially if the defect is not associated with an effective pulmonary stenosis, early surgical intervention is needed. In a study of 200 lung specimens from patients with TGV, Newfeld and his co-workers 1 showed that large VSD's uniformly caused significant pulmonary vascular disease early in life; they concluded that surgical intervention to protect the pulmonary vascular bed should be undertaken within the first 6 months of life. Our clinical experience in Case 3 (indicated by an open circle with a cross in Fig. 9) showed that pulmonary artery banding in a 9-month-old child was ineffective because severe pulmonary vascular disease had already developed. Of 3 patients (open circles, Fig. 9) who did not have any protection to the lung, 2 (Cases 4 and 6) had Grade IV irreversible damage at 22 and 19 months of age and 1 (Case 9) had Grade III at 5 months of age; in contrast, the patients with VSD and pulmonary stenosis (triangles and dark circles) did not develop any significant pulmonary vascular disease, even at an older age. The question as to whether early surgical intervention should be closure of the VSD or pulmonary artery banding followed by later correction is not yet fully answered. Some centers report performing the correction in early infancy while others prefer the
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palliative procedure first, followed by repair at an older ageY-17 Carpena and Subramanian," in an analysis of 44 operations on patients with TGV and VSD, concluded that primary definitive repair in early infancy carried a higher mortality rate (33 per cent) than did early banding followed by early debanding and primary correction later in the first year of life (no deaths). The question of which approach to use cannot be settled until a large group of patients has been operated upon and until the combined mortality, morbidity, and late results of banding and debanding are compared with those of early primary correction. It appears to us that later repair of the VSD, when the heart is larger, would be technically easier to perform through the tricuspid valve; this approach avoids the need of an incision in the systemic ventricle. In the patients who have a VSD associated with subvalvular stenosis, it would be technically more advantageous to wait until an older age for management of the stenosis, particularly if it is of the type that may require a Rastelli" procedure. We have not used the Rastelli procedure in cases of VSD associated with subvalvular stenosis, even though in 2 patients the narrowing was rather diffuse and long. Our results are satisfactory at present; none of the patients has died. However, postoperative cardiac catheterizations have not yet been performed to assess the effectiveness of the valvular resection. Certainly, as noted by Trusler and Mustard," the surgeon should be ready to perform a Rastelli procedure whenever he encounters a long subvalvular narrow tunnel that cannot be widened. Our autopsy studies and clinical experience indicate that almost all VSD's in simple transposition can be surgically approached through the tricuspid valve orifice. During the operation, with the heart relaxed and with the aid of traction sutures on the rim of the defect, all locations on the ventricular septum except the apical portion can be reached. The uncommon apical
muscular VSD is difficult to repair from the right side of the septum either through the tricuspid valve or via a right ventriculotomy. Although closure could be accomplished by compression of the septum by sutures placed through the apex of the heart or directly through a left ventriculotomy, the apical defects appear to be better visualized from the left side of the septum. Furthermore, an incision in the pulmonary ventricle is not functionally as significant as an incision in the systemic right ventricle. REFERENCES Newfeld, E., Paul, M. H., Muster, A. J., and Idriss, F. S.: Pulmonary Vascular Disease in Complete Transposition of the Great Arteries: Study of 200 Patients, Am. J. Cardiol, 34: 75, 1974. 2 Heath, D., and Edwards, J. E.: The Pathology of Hypertensive Pulmonary Vascular Disease: A Description of Six Grades of Structural Changes in the Pulmonary Arteries With Special Reference to Congenital Cardiac Septal Defects, Circulation 18: 533, 1958. 3 Lev, M., Rimoldi, H. J. A., Eckner, F. A. 0., Melhuish, B. P., Meng, L., and Paul, M. H.: The Taussig-Bing Heart, Arch. Pathol. 81: 24, 1966. 4 Lindesmith, G. G., Stiles, Q. R., Tucker, B. L., Gallaher, M. E., Stanton, R. E., and Meyer, B. W.: The Mustard Operation as a Palliative Procedure, J. THoRAe. CARDIOVASC. SURG. 63: 75, 1972. 5 Mustard, W. T.: Successful Two-Stage Correction of Transposition of the Great Vessels, Surgery 55: 469, 1964. 6 Albert, H. M.: Surgical Correction of Transposition of the Great Vessels, Surg. Forum 5: 74, 1954. 7 Senning, A.: Surgical Correction of Transposition of the Great Vessels, Surgery 45: 966, 1959. 8 Merendino, K. A, Jesseph, 1. E., Herron, P. W., Thomas, G. I., and Vetto, R. R.: Interatrial Venous Transposition: A One-Stage Intracardiac Operation for the Conversion of Complete Transposition of the Aorta and Pulmonary Artery to Corrected Transposition. Theory and Clinical Experience, Surgery 42: 898, 1957. 9 Shumacker, H. B, Jr.: A New Operation for Transposition of the Great Vessels, Surgery 50: 773, 1961. 10 Idriss, F. S., Koopot, R., Paul, M. H., Nikaidoh, H., Riker, W. L., and Muster, A. J.: Transposition of the Great Arteries (TGA):
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Evolution of Surgical Technic in 60 Cases, Read at the forty-second Annual Meeting of the American Academy of Pediatrics, Cardiology Section, Chicago, Illinois, October 2024, 1973. 11 Bonchek, L. I., and Starr, A.: Total Correction of Transposition of the Great Arteries in Infancy as Initial Surgical Management, Ann. Thorac. Surg. 14: 376, 1972. 12 Subramanian, S., and Wagner, H.: Correction of Transposition of the Great Arteries in Infants Under Surface-Induced Deep Hypothermia, Ann. Thorac. Surg. 16: 391, 1973. 13 Clarkson, P. M., Barratt-Boyes, B. G., Neutze, J. M., and Lowe, J. B.: Results Over a TenYear Period of Palliation Followed by Corrective Surgery for Complete Transposition of the Great Arteries, Circulation 45: 1251, 1972. 14 Kilman, J. W., Williams, T. E., Jr., Kakos, G. S., Craenen, 1., and Hosier, D. M.: Surgical Correction of the Transposition Complex in Infancy, J. Thorac. Cardiovasc. Surg. 66: 387, 1973. 15 Danielson, G. K., Mair, D. D., Ongley, P. A., Wallace, R. B., and McGoon, D. C.: Repair of Transposition of the Great Arteries by Transposition of Venous Return, J. THORAC. CARDIOVASC. SURG. 61: 96, 1971. 16 Trusler, G. A., and Mustard, W. T.: Palliative and Reparative Procedures for Transposition of the Great Arteries, Ann. Thorac. Surg. 17: 410, 1974. 17 Breckenridge, I. M., Oelert, H., Stark, 1., Graham, G. R., Bonham-Carter, R. E., and Waterston, D. J.: Mustard's Operation for Transposition of the Great Arteries: Review of 200 Cases, Lancet 1: 1140, 1972. 18 Carpena, c., and Subramanian, S.: Management of the Ventricular Septal Defect in Transposition (Abstr.) , Am. J. Cardio\. 33: 130, 1973. 19 Rastelli, G. C., McGoon, D. C., and Wallace, R. B.: Anatomic Correction of Transposition of the Great Arteries With Ventricular Septal Defect and Sub pulmonary Stenosis, J. THORAC. CARDIOVASC. SURG. 58: 545, 1969.
Discussion DR. RANDALL GRIEPP Palo Alto, Calif.
I should like to congratulate the authors on a very impressive surgical series. At the Stanford University Hospital, 26 patients with TGV and large, nonrestrictive VSD's have undergone operative correction. Seventeen patients underwent VSD closure and intra-atrial baffling via the Mustard technique, In 13 patients
the VSD was closed via a right ventriculotomy. Six of these patients died, for an operative mortality rate of 46 per cent. Four patients underwent closure of the VSD through the tricuspid valve. All of these patients survived. Thus this portion of the experience supports the authors' contention that the preferred approach for VSD closure is through the right atrium. However, the late results in both the patients who underwent ventriculotomy and in those who did not have not been satisfactory. The majority of the patients required digitalis and diuretics to prevent fluid accumulation, and most have moderate-to-marked exercise intolerance. In 9 patients in our series, this combination of defects was corrected by means of the Rastelli technique. Via a right ventriculotomy, a Teflon patch was placed encompassing the VSD and the aortic valve. The pulmonary artery was detached from the left ventricle and the proximal end was closed. A Dacron tube graft was anastomosed between the right ventriculotomy and the distal pulmonary artery. In 3 patients a porcine heterograft valve was included in the graft. All of these patients survived the operation. In 6 patients no valve was utilized within the conduit, and 3 of them died. However, all 6 patients who survived surgery have had extremely satisfactory late results as measured by exercise tolerance and need for digitalis and diuretic therapy. On the basis of this experience, our present approach to the large VSD and transposition is as follows. The right atrium is opened, and the feasibility of baffling the left ventricular outflow through the aortic valve is assessed by direct observation of the VSD and palpation of the crista supraventricularis. If it is felt that a Rastelli procedure is possible, a ventriculotomy is made and the Rastelli operation is carried out with a valve conduit. If it is decided that a Rastelli procedure is not feasible, owing to a small VSD that cannot be practically enlarged, a prominent crista supraventricularis, or excessive distance between a VSD and the aortic valve, then the VSD is closed through the tricuspid valve and a Mustard procedure is then carried out. DR. IDRISS (Closing) First, we cannot discuss the Rastelli procedure with experience, because we have not performed the technique. The subvalvular pulmonary stenosis encountered in these patients was rather severe in 6 cases. In 4, the stenosis was discrete, and the resection was not very difficult. We were able to take a wedge out of the area. In 2 patients, the stenosis was a somewhat longer fibromuscular
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tunnel, and again we were able to resect it. Of course, the ultimate result cannot be assessed until postoperative catheterization has been done and the results assessed. At this time, all we can say is that those patients are alive. Dr. Griepp, the question of performing a Ras-
telli in some of these patients should be viewed in relation to our pathology study. This study showed that most of the VSD's are below the crista; the crista is quite wide, so that in most patients a Rastelli type of procedure may be difficult to accomplish.