Intermediate-term survival and functional results after arterial repair for transposition of the great arteries

Surgery for Congenital Heart Disease

Intermediate-term survival and functional results after arterial repair for transposition of the great arteries An assessment of late morbidity and mortality is essential before arterial repair can be considered truly corrective for patients with transposition of the great arteries. We describe the early and intermediateterm results in 126 patients who underwent arterial repair. Operation was performed at a median age of 6 days, with 76 patients operated on within the first 7 days of life. Coronary artery anatomy differed from the usual arrangement in 37 patients. Simultaneous procedures included ventricular septal defect closure (35) and repair of interrupted aortic arch (2) or coarctation (5). Hospital mortality was seven of 126 (5.5 %), with three deaths among the most recent 100 patients (3%). There were one late, noncardiac death and one late death after reoperation. Reoperation for pulmonary artery stenosis was required in 10 of the first 63 patients (16%), all of whom underwent pulmonary artery reconstruction with separate. patches for closure of the coronary excision sites. Of the last 63 patients, all of whom underwent pulmonary artery reconstruction with a single pantaloon-shaped pericardial patch, one (2 %) required reoperation for pulmonary artery stenosis. Doppler flow studies and echocardiography performed in 115 of 119 surviving patients at a mean of 12 months after repair demonstrated normal left ventricular function, minimal left ventricular outflow gradients, and no more than trivial aortic regurgitation. Peak gradient across the right ventricular outflow tract was 19 ± 3 mm Hg in patients with separate pulmonary artery patches and 5 ± 2 mm Hg in those with a single pantaloon patch (p = 0.0001). Follow-up is 96% complete from 1 month to 8 years after operation (mean 2.5 years). The actuarial survival rate at 5 years, including operative mortality, was 92 %. AU patients are in sinus rhythm, and none requires antiarrhythmic medications. These data suggest that pulmonary artery reconstruction with a single pantaloon patch may be associated with a decreased requirement for reoperation. Intermediate-term survival and functional results are excellent after arterial repair for transposition of the great arteries. (J THORAC CARDIOVASC SURG 1992;103:421-7)

Flavian M. Lupinetti, MDa (by invitation), Edward L. Bove, MD,a L. LuAnn Minich, MD b (by invitation), A. Rebecca Snider, MDb (by invitation), Louise B. Callow, RNa (by invitation), Jon N. Meliones, MDb (by invitation), Dennis C. Crowley, MDb (by invitation), Robert H. Beekman, MDb (by invitation), Gerald Serwer, MD b (by invitation), Macdonald Dick II, MDb (by invitation), Roger Vermilion, MDb (by invitation), and Amnon Rosenthal, MD,b Ann Arbor, Mich.

From the Section of Thoracic Surgery, Department of Surgery ,a and the Division of Pediatric Cardiology, Department of Pediatrics, b the University of Michigan School of Medicine, Ann Arbor, Mich.

Address for reprints: Flavian M. Lupinetti, MD, University of Michigan Hospital, Section of Thoracic Surgery, 2120 Taubman Center, Box 0344, Ann Arbor, MI 48109.

Read at the Seventy-first Annual Meeting of The American Association for Thoracic Surgery, Washington, D.C., May 6-8, 1991.

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Arterial switch repair has evolved as the procedure of choice in most centers for treatment of complete transposition of the great arteries (TGA). The arterial repair, in contradistinction to atrial repairs, offers the important advantage of maintaining the left ventricle as the systemic ventricle. Furthermore, the arterial repair may avoid some of the adverse sequelae of atrial repair, such as ventricular dysfunction, 1-5 baffle stenosis.v" arrhythmias.?"! and systemic atrioventricular valve insufficiency.I" The initial experience with the arterial repair was associated with a high operative mortality, however, and the late advantages of this procedure had to be regarded in the context of this presumably higher immediate risk. Although atrial repair of TGA has long been accomplished with a low operative mortality, attrition among patients awaiting atrial repair must also be considered and may have been unappreciated in the past. 12 With increasing experience and refinement of operative technique for arterial repair, many centers have now obtained low operative death rates that compare favorably with those obtained with the Mustard or Senning procedure. B - 15 In addition, the routine performance of arterial repair within the first 2 weeks of life has obviated questions of patient selection or death occurring before scheduled operation. Demonstration oflow operative mortality alone, however, may not be adequate reason to abandon the established methods of atrial correction. Only with detailed postoperative evaluation and careful follow-up examinations can the results of arterial switch for TGA be conclusively evaluated. This report addresses the experience of one center with arterial repair, with respect both to operative results and to intermediate-term followup.

Patients and methods The hospital records of all patients undergoing an arterial switchprocedure for TGA at C. S. Mott Children's Hospital of the University of Michigan Medical Center were reviewedfor details of preoperative assessment,operative management, and postoperative outcome. Preoperative diagnosis was confirmed by echocardiography. Cardiac catheterization with balloon atrial septostomywas performed when necessaryto assure atrial mixing. All patients with atrioventricular concordance, balanced ventricles, and absence of left ventricular outflow tract obstruction were considered for arterial repair. Early in this experience, arterial repair was selectively used, generally for those patients with TGA and a large ventricular septal defect (YSD). BeforeJuly 1985, most patients with TGA at this institution received either a Mustard or a Senning procedure; subsequently, arterial repair has been considered the procedure of choice for all suitable patients with TGA. Since July 1985 an atrial repair was performed in only one patient with TGA and intact ventricular septum for whom arterial repair was planned. In that patient, treated early in our experience, an intramural left coronary artery was found at operation. At that time this

coronaryanatomy was consideredto be an unacceptableriskfor arterial switch repair, and a Senning procedure was performed instead. Three other patients with the Taussig-Bing anomaly underwent primary intraventricular repair. Operations were performed with systemichypothermia (20 0 C) and a singledose of cold sanguineous cardioplegic solution. Complete circulatory arrest was selectively used, primarily for treatment of associated aortic arch defects but also for some small neonates for whom obtaining adequate venous drainage was problematic. In nearly all patients, arterial switch repair was performed by means of the Lecompte maneuver for anterior translocationofthe pulmonary arteries. 16 This wasnot used when the great vessels were side by side, however. Operations performed before October 1988 included reconstructionof the pulmonary artery with separate pericardial patch reconstruction of each defect resulting from transfer of the coronary arteries. The techniqueofoperation from October 1988 through the present has been described previously. I? The current method of repair emphasizes the use of a large, pantaloon-shaped patch of glutaraldehyde-preserved autologous pericardium to close both coronary artery sites and enlarge the neopulmonary root, as initially described by Idriss and colleagues.V Two patients seen initially at later than 1 month of age underwent two-stage repairs. The initial operation consistedof pulmonary artery banding and construction of a modified Blalock-Taussig shunt. Arterial switch and takedown of the shunt were performed 1 week later. M-mode and two-dimensional echocardiography with Doppler flow studies were used to assist in postoperativeassessment and long-term evaluation as previously described.'? Cardiac wall motion and valve function were assessed. Doppler peak instantaneous gradients were calculated by the simplified Bernoulli equation. Patients with appropriate indications underwent postoperative cardiac catheterization studies. Mean values ± standard error of the mean were calculated. Comparisonsbetween subgroupswere performed by x2 analysisor Student's t test for unpaired data. Late follow-up status was ascertained from outpatient records from this institution or by contact with the referring physician.Actuarial analysisof survivaland reoperation-freesurvivalwere performed by standard methods.P'

Results From 1982 through April 1991, 126 patients, 90 male and 36 female, underwent the arterial switch operation. Few procedures were performed before July 1985 (Fig. 1). The operation was performed at a median patient age of 6 days, with 76 operations performed within the first 7 days of life and 104 operations performed within the first 30 days. At operation, predominantly anteroposterior great arteries and usual coronary anatomy (1 Lex: 2R according to the Leiden convention") were observed in 89 patients. Other morphologic relationships were found in the remaining 37 patients, and these are detailed in Table I. With the exception of the initial patient with an intramural left coronary artery who underwent a Senning procedure, arterial repair was performed in all patients

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Arterial repair for TGA

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30

r-----------

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92%

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57

44

24

12

6

3

3

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36

48

60

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Patients followed through interval

MONTHS AFTER OPERATlON

1982-83 1984

1985

1986

1987

1988

1989

1990 Jan-Apr 91

Fig. 2. Intermediate-term patientsurvival after arterial repair for transposition of the great arteries. The actuarial survival rate, including operative mortality,was 92% at 5 years.

YEAR

Fig. 1. Yearly number of arterial repairs for transposition of thegreat arterieshas increased from 4 in 1982 to 1983 to 26 in 1990.

regardless of the coronary artery anatomy. This included six patients who had a single coronary trunk and three patients with intramural coronary arteries. Operative mortality in patients with usual coronary anatomy (3/89, 3%) was lower than that in patients with other coronary anatomy (4/37, 12%; P = 0.1). A single nonrestrictive VSD was present in 34 patients, and each was closed with a Dacron patch. No significant difference in operative mortality was observed between patients with a single large VSD (2/34, 6%) and those with intact ventricular septum (4/91, 4%; P = 0.3). One patient with multiple VSDs died at operation. Additional operative procedures performed simultaneously included repair of interrupted aortic arch in two patients (one death) and repair of coarctation of the aorta irifive patients (no deaths). In the entire series of 126 patients undergoing arterial switch there were seven perioperative deaths (5.5%) Of the last 100 patients undergoing this procedure, only three died. All three of the most recent deaths occurred in patients with complex associated defects: interrupted aortic arch, VSD, and subaortic stenosis in one; multiple VSDs in a second; and dextrocardia in the third. All perioperative deaths were related to low cardiac output and occurred within 72 hours of operation. Postoperative follow-up is 96% complete. Patients have beenfollowed up for 1 month to 8 years, with a mean follow-up of 2'12 years. There have been two late deaths among operative survivors, one from noncardiac causes and one after reoperation for both pulmonary artery stenosis and coronary artery stenosis. The latter patient initiallyhad TGA, intact ventricular septum, side-by-side great vessels, and a single right coronary artery. The

Table I. Morphology ofgreat arteries and coronary arteries Anteroposterior relations of great arteries Usual coronary anatomy (lLCx; 2R) Other than usual coronary anatomy IL;2CxR 2LCxR I LCx; 2R intramural IL intramural; 2RCx ILR,2Cx ILRCx Taussig-Bing anomaly with side-by-side great arteries IR; 2LCx 2LCxR lLR,2Cx

119

89 30

20 5 I 2 1

I 7 5 I 1

L, Left anterior descending coronary artery; ex, circumflex coronary artery; R, right coronary artery.

actuarial 5-year survival rate in the entire series, including operative mortality, is 92% (Fig. 2). Twenty-four patients have undergone follow-up cardiac catheterization including coronary angiography. In one patient ostial stenosis of a single coronary artery was discovered in addition to supravalvular pulmonary stenosis. All other patients were free of coronary stenosis. In no other patient has clinical or electrocardiographic evidence of coronary insufficiency developed. Two-dimensional and Doppler echocardiographic examinations were performed in 115 of 119 surviving patients at a mean duration after initial operation of 12 months. With the exception of one patient whose ventricular function was graded "poor," all patients displayed normal left ventricular wall motion and shortening fraction. In 25 patients some degree of aortic insufficiency was noted; in all cases this was considered "mild" or "trivial."

The Journal of Thoracic and Cardiovascular

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Surgery

100

80

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' - - - - Group I

%

68% 40

20

2.4 2 ~~7:~e~I ~~:::n;~ 'ntervar 56 55 44 24 12 6 3 '-

12

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MONTHS AFTER OPERAnON

Fig. 3. Actuarial survival without reoperation according to methodof pulmonary artery reconstruction. Group I (separate pericardial patches) survival rate, including operative mortality, withoutreoperation was 84% at 2 yearsand 68% at 5 years. Survival rate,including operative mortality, withoutreoperation in groupII (single pantaloon-shaped patch)was93% at 2 years. Large left ventricular outflow tract gradients were found in two patients. One patient with a 29 mm Hg peak gradient on Doppler study underwent cardiac catheterization, which found no anatomic or hemodynamic evidence of obstruction. A second patient with a 54 mm Hg peak gradient measured by Doppler flow studies was found at subsequent catheterization to have a subvalvular membrane and a 35 mm Hg gradient. Evaluation by Doppler flow studies and cardiac catheterization demonstrated supravalvular pulmonary stenosis in II patients, all of whom underwent reoperation to relieve this problem. In all patients this stenosis was detected during the first study performed after operation. Early in this series the first postoperative study was a cardiac catheterization performed 1 year after arterial repair. More recently, routine postoperative echocardiography and Doppler flow studies performed within the first 2 weeks postoperatively have constituted the initial follow-up studies. Thus in four of the 11 significant cases of supravalvular pulmonary stenosis, diagnosis was made I year after operation, while in seven ofthe II it was made within the first postoperative month. In no patient with a normal transpulmonary gradient demonstrated by any postoperative study did pulmonary stenosis subsequently develop. Subgroup analysis was based on the methods of pulmonary artery reconstruction used. Pulmonary artery reconstruction with separate pericardial patches was done in the first 63 patients (group I). Reconstruction with a single pantaloon-shaped patch was performed in the last 63 patients (group 11).The right ventricular outflow peak gradient was 19 ± 3 mm Hg in group I patients and 5 ± 2 mm Hg in group II patients (p = 0.0001). Reoperations were performed in 10 of 63 group I patients

(16%) and in one of 58 group II patients (2%). Duration from arterial repair to reoperation was 6 months to 5 years (mean 31 ± 6 months). One patient with coronary and pulmonary artery stenosis died at reoperation; all others are alive and well. The actuarial survival rate, including operative mortality, without reoperation was 84% at 2 years and 68% at 5 years in group I. In group II the actuarial survival rate, including operative mortality, without reoperation was 93% at 2 years (Fig. 3). Only two other patients in this series required additional thoracic surgical procedures at a later date. One patient underwent diaphragmatic plication for a paralyzed hemidiaphragm. Another patient was discovered to have an aortic coarctation that was not appreciated at initial evaluation. Both problems were corrected without complication. Follow-up l2-lead electrocardiograms have shown all patients to be in sinus rhythm, and none requires antiarrhythmic medications.

Discussion The arterial switch repair is now routinely performed in many institutions, with low perioperative morbidity and mortality and with adequate growth of coronary and aortic anastomoses.P For the benefits of this approach compared with atrial level repairs to be established conclusively, the results of the arterial switch must be assessed over a similarly long postoperative period. Because many late complications of atrial repair do not occur with great frequency until the second decade after operation, our present length of follow-up of patients undergoing arterial repair may be inadequate to demonstrate that the latter approach is superior. However, the length of follow-up provided in this investigation demonstrates that late sequelae of arterial repair are uncommon. Furthermore, it is highly likely that these results will be maintained even over a substantially greater time. Certain trends have emerged from this study that are relevant in both the preoperative planning and postoperative evaluation of patients undergoing arterial repair. First and foremost, left ventricular function appears to be well preserved up to 8 years after the arterial switch procedure. Ventricular mechanics of patients after arterial switch have been reported to be virtually identical to those of age-matched control patients.P In patients with atrial repair, right (systemic) ventricular ejection fraction and response to afterload stress are frequently abnormal.': S Although systemic ventricular function is often normal at rest after atrial repair, profound abnormalities can often be detected during exercise.P': 2S Atrial repair in patients with TGA and VSD may result in an even greater degree of functional deterioration than in patients with TGA and intact ventricular septum."

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Second, neoaortic valve function does not appear to be compromised by arterial repair. The neoaortic valve is able to adapt to systemic pressures and to remain competent, at least when operation is performed early. Martin and associates/" observed that some degree of aortic insufficiency is detectable by Doppler echocardiography, contrast aortography, or both methods in 40% of their patients approximately 4 years after arterial repair. However, the severity of aortic insufficiency was judged to be trivial in all patients.l? Because only minimal insufficiency was demonstrated in approximately one of six patients in our series, and because in no patient has this progressed during as much as 8 years of follow-up, it appears reasonable to expect that serious problems related to aortic insufficiency will be rare. Third, right ventricular outflow tract obstruction is a potentially important problem after arterial repair of TGA. In other series, neopulmonary outflow tract obstruction has been the most common reason for reoperation and has been responsible for 75% of reoperations performed.l' By contrast, the use of a single pericardial patch to close the coronary defects and to enlarge the entire neopulmonary trunk has been associated with normal pulmonary artery growth and low right ventricular pressures.F' Supravalvular pulmonary stenosis necessitated II reoperations in this series. The stenosis was treated successfully in 10 patients, with one death due to unrelievedcoronary artery stenosis. Although all surviving patients are now asymptomatic, it remains a subject of concern. Reconstruction of the neopulmonary artery with individual discs of pericardium may have contributed to the high prevalence of supravalvular pulmonary stenosis seen in the earlier part of this series. Pulmonary artery enlargement with the pantaloon patch, as used in the latter half of the present series, has resulted in lower outflow tract gradients and has virtually eliminated the need for reoperation. All patients in this series requiring reoperation had evidence of significant supravalvular pulmonary stenosis early after operation, whereas no patient shown to be free of pulmonary stenosis later acquired this complication. Thus although our period of follow-up with the pantaloon patch enlargement is shorter, the very low gradients observed in group II patients suggest that this low rate of reoperation will be maintained in the future. Additional follow-up of group II will be necessary to substantiate this preliminary impression. No difficulties related to arrhythmias were encountered in this series. As with some of the other late postoperative complications, comparisons with atrial repairs must await a longer duration of follow-up. However, our experienceconfirms the observations of others that clinicallyimportant arrhythmias are not prevalent within the

Arterial repair for TGA

42 5

first several years after arterial repair.P' Atrial correction of TGA, on the other hand, has been associated with a disturbingly high prevalence of serious arrhythmias."!' As few as 50% to 60% of patients with atrial correction of TGA are in stable sinus rhythm by 7 to 8 years after operation, although loss of sinus rhythm may not correlate with increased risk of morbidity or mortality.v'? Antiarrhythmic drugs are the most commonly required medications in patients after atrial repair. I I Differences between the Mustard and Senning repairs with respect to late development of arrhythmias appear to be small or nonexistent," The technical details of arterial switch now appear to be firmly established. A nonrestrictive VSD does not appear to increase the mortality of early anatomic correction significantly. The late results of operation in this subgroup were indistinguishable from those with simple TGA. It has been observed previously that TGA with a VSD, like TGA with intact ventricular septum, is best treated early in infancy to avoid complications of pulmonary vascular disease.29, 30 Quaegebeur and colleagues'! found that a large VSD was an incremental risk factor for operative death. Nevertheless, they concluded that arterial repair is preferred over atrial repair in such patients, in part because of the superior late results in operative survivors of anatomic correction. We prefer to treat the patient with an important VSD in the same manner as we would a patient with intact ventricular septum, performing anatomic correction within the first 2 weeks of life. Although abnormalities of coronary anatomy had minimal effects on operative outcome in the present series, unusual coronary patterns have been shown to cause difficulties with arterial switch in earlier reports. 31-33 The increased operative risk associated with these variations in coronary anatomy has been largely eliminated with increasing experience. Repair of interrupted aortic arch or aortic coarctation was performed in seven patients in this series, resulting in one death. Excellent results of anatomic repair for TGA and arch obstruction have been described previously.l" The Taussig-Bing malformation also appears amenable to arterial switch. A more challenging problem is the patient who is seen for the first time after the neonatal period. The rapid two-stage correction as outlined by Jonas and associates'> has been successful in two patients recently treated in this institution. In such patients, the principles of ventricular preparation to be emphasized are achieving a moderate degree of pulmonary banding and a large volume overload of the left ventricle.l? In summary, arterial repair for TGA can now be accomplished with reproducible operative results, includ-

4 2 6 Lupinetti et al.

ing a low hospital mortality, excellent intermediate-term survival, infrequent need for reoperation, and normal ventricular function. The prevalence of important valvular stenosis or insufficiency now appears negligible, as does the prevalence of significant rhythm disturbances. It is anticipated that these trends will be maintained over longer periods of follow-up and that arterial repair will become firmly established as the optimal approach to the treatment of patients with TGA. REFERENCES 1. Martin RP, Qureshi SA, Ettedgui JA, et al. An evaluation of right and left ventricular function after anatomical correction and intra-atrial repair operations for complete transposition of the great arteries. Circulation 1990;82:80816. 2. Graham TP Jr, Atwood GF, Boucek RJ Jr, Boerth RC, Bender HW Jr. Abnormalities of right ventricular function following Mustard's operation for transposition of the great arteries. Circulation 1975;52:678-84. 3. BenderHW Jr,StewartJR,Merrill WH,HammonJW Jr, Graham TP Jr. Ten years' experience with the Senning operation for transposition of the great arteries: physiologic results and late follow-up. Ann Thorac Surg 1989;47:21823. 4. Turina MI, Siebenmann R, von Segesser L, Schon beck M, Senning A. Late functional deterioration after atrial correction for transposition of the great arteries. Circulation 1989;80(Pt 2):I162-7. 5. Kato H, Nakano S, Matsuda H, Hirose H, Shimazaki Y, Kawashima Y. Right ventricular myocardial function after atrial switch operation for transposition of the great arteries. Am J Cardiol 1989;63:226-30. 6. AshrafMH, Cotroneo J, DiMarco D, Subramanian S. Fate long-term survivors of Mustard procedure (inflow repair) for simple and complex transposition of the great arteries. Ann Thorac Surg 1986;42:385-9. 7. Arciniegas E, Farooki ZQ, Hakimi M, Perry BL, Green EW. Results of the Mustard operation for dextro-transposition of the great arteries. J THORAC CARDIOVASC SURG 1981;81:580-7. 8. Kron IL, Rheuban KS, Joob A W, et al. Baffle obstruction following the Mustard operation: cause and treatment. Ann Thorac Surg 1985;39:112-5. 9. Deanfield J, Camm J, Macartney F, et al. Arrhythmia and late mortality after Mustard and Senning operation for transposition of the great arteries: an eight-year prospective study. J THORAC CARDIOVASC SURG1988;96:56976. 10. Flinn CJ, Wolff GS, Dick M II, et al. Cardiac rhythm after the Mustard operation for complete transposition of the great arteries. N Engl J Med 1984;310: 1635-8. 11. Trusler GA, Williams WG, Duncan KF, et al. Results with Mustard operation in simple transposition of the great arteries 1963-1985. Ann Surg 1987;206:251-60.

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12. Rubay J, de Leval M, Bull C. To switch or not to switch? The Senning alternative. Circulation 1988;78(Pt 2):III 1-4. 13. Norwood WI, Dobell AR, Freed MD, Kirklin JW, Blackstone EH. Intermediate results of the arterial switch repair: a 20-institution study. J THORAC CARDIOVASC SURG 1988; 96:854-63. 14. Planceh C, Bruniaux J, Lacour-Gayet F, et al. Swith operation for transposition of the great arteries in neonates: a study of 120 patients. J THORAC CARDIOVASC SURG 1988; 96:354-63. 15. Wernovsky G, Hougen TJ, Walsh EP, et al. Midterm results after the arterial switch operation for transposition of the great arteries with intact ventricular septum: clinical, hemodynamic, echocardiographic, and electrophysiologic data. Circulation 1988;77:1333-44. 16. Lecompte Y, Zannini L, Hazan E, et al. Anatomic correction of transposition of the great arteries: new technique without use of a prosthetic conduit. J THORAC CARDIOVASC SURG 1981;82:629-31. 17. Bove EL. Current technique of.the arterial switch procedure for transposition of the great arteries. J Cardiac Surg 1989;4:193-9. 18. Idriss FS, Ilbawi MN, DeLeon S, et al. Arterial switch in simple and complex transposition of the great arteries. J THORAC CARDIOVASC SURG 1988;95:29-36. 19. Martin MM, Snider AR, Bove EL, et al. Two-dimensional and Doppler echocardiographic evaluation after arterial switch repair in infancy for complete transposition of the great arteries. Am J CardioI1989;63:332-6. 20. Grunkemeier GL, Starr A. Actuarial analysis of surgical results: rationale and method. Ann Thorac Surg 1977;24: 404-8. 21. Gittenberger-de Groot AC, Sauer U, Oppenheimer-Dekker A, Quaegebeur J. Coronary arterial anatomy in transposition of the great arteries: a morphologic study. Pediatr Cardiol 1983;4(suppl 1):15-24. 22. Arensman FW, Sievers H, Lange P, et al. Assessment of coronary and aortic anastomoses after anatomic correction of transposition of the great arteries. J THORAC CARDIOVASC SURG 1985;90:597-604. 23. Colan SD, Trowitzch E, Wernovsky G, Sholler GF, Sanders SP, Castaneda AR. Myocardial performance after arterial switch operation for transposition of the great arteries with intact ventricular septum. Circulation 1988; 78:132-41. 24. Reybrouck T, Dumoulin M, Van der Hauwaert LG. Cardiorespiratory exercise testing after venous switch operation in children with complete transposition of the great arteries. Am J CardioI1988;61:861-5. 25. Musewe NN, Reisman J, Benson LN, et al. Cardiopulmonary adaptation at rest and during exercise 10 years after Mustard atrial repair for transposition of the great arteries. Circulation 1988;77: 1055-61. 26. Martin RP, Ettedgui JA, Qureshi SA, et al. A quantitative evaluation of aortic regurgitation after anatomic correction of transposition of the great arteries. J Am Coll Cardiol 1988;12:1281-4.

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27. Paillole C, Sidi D, Kachaner J, et al. Fate of pulmonary artery after anatomic correction of simple transposition of great arteries in newborn infants. Circulation 1988;78: 870-6. 28. Martin RP, Radley-Smith R, Yacoub MH. Arrhythmias before and after anatomic correction of transposition of the great arteries. J Am Coli Cardiol 1987;10: 200-4. 29. Bove EL, Beekman RH, Snider AR, et al. Arterial repair for transposition of the great arteries and large ventricular septal defect in early infancy. Circulation 1988;78(Pt 2):III26-31. 30. Di Donato RM, Wernovsky G, Walsh EP, et al. Results of the arterial switch operation for transposition of the great arteries with ventricular septal defect: surgical considerations and midterm follow-up data. Circulation 1989;80: 1689-705. 31. Quaegebeur JM, Rohmer J, Ottenkamp J, et al. The arterial switch operation: an eight-year experience. J THORAC CARDIOVASC SURG 1986;92:361-84. 32. Mayer JE Jr, Sanders SP, Jonas RA, Castaneda AR, Wernovsky G. Coronary artery pattern and outcome of arterial switch operation for transposition of the great arteries. Circulation I990;82(Pt 2):IVI39-45. 33. Yamaguchi M, Hosokawa Y, Imai Y, et al. Early and midterm results of the arterial switch operation for transposition of the great arteries in Japan. J THORAC CARDIOVASC SURG 1990;100:261-9. 34. PigottJD,ChinAJ, Weinberg PM, WagnerHR,Norwood WI. Transposition of the great arteries with aortic arch obstruction: anatomical review and report of surgical management. J THORAC CARDIOVASC SURG 1987;94: 82-6. 35. Jonas RA, Giglia TM, Sanders SP, et al. Rapid two-stage arterial switch for transposition of the great arteries and intact ventricular septum beyond the neonatal period. Circulation 1989;80(Pt 2):1203-8. 36. Ilbawi MN, Idriss FS, DeLeon SY, et al. Preparation of the left ventricle for anatomical correction in patients with simple transposition of the great arteries: surgical guidelines. J THORAC CARDIOVASC SURG 1987;94:8794.

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Discussion Dr. William G. Williams (Toronto. Ontario, Canada). We should not underplay the significance of right ventricular outflow tract obstruction. Together with Mr. Chris Lincoln, I reviewed our combined series of 178 survivors of anatomic repair with a 13-year follow-up.Late reoperation was necessary in 20 of those 178 patients. This combined series was of interest in that each of us had different techniques for reconstructing the right ventricular outflow tract. One of us used primarily the Lecompte procedure and the other primarily a direct anastomosis. We found it interesting that the technique of repair did not make a difference in the prevalence of right ventricular outflow tract stenosis. Of surprise to us was the fact that treating the pericardium with glutaraldehyde (either bovine pericardium or autogenous pericardium) increased the prevalence of right ventricular outflow tract stenosis. Do you have any evidence whether the use of glutaraldehyde in your experience is beneficial? Dr. Lupinetti. There are no particular technical aspects that can be generalized in the treatment of TGA. It requires highly individualized treatment depending on the peculiarities of the individual anatomy. Certainly adequate mobilization of the coronary button and proper reimplantation, including the axial rotation on the coronary button, are essential to achieving a tension-free reanastomosis of the coronary artery. We are not certain why the pantaloon patch has worked better. We believe that this improvement is related to an enlargement of the neopulmonary root, and similarly we are unable to provide any specificevidence regarding the benefits of glutaraldehyde or the benefits of autologous pericardium. Autologous pericardium treated with glutaraldehyde has been used throughout the entire series; we cannot address the advantages or disadvantages of other techniques. We agree that the definitive technical questions of arterial repair have yet to be adequately answered. Certainly the problem of right ventricular outflow tract obstruction has afflicted operative results in a number of centers with otherwise good results. We stress, however, the virtues of early and frequent reexamination with echocardiograms. We have observed that the subsequent right ventricular outflow tract obstruction is virtually nonexistent if it can be documented in the earliest postoperative studies that an iatrogenic narrowing of the pulmonary root has been avoided.