Surgical Results in Patients With Double Outlet Right Ventricle: A 20-Year Experience

Transcription

1 Surgical Results in Patients With Double Outlet Right Ventricle: A 20-Year Experience John W. Brown, MD, Mark Ruzmetov, MD, Yuji Okada, MD, Palaniswamy Vijay, PhD, MPH, and Mark W. Turrentine, MD Section of Cardiothoracic Surgery, James W. Riley Hospital for Children, and Indiana University School of Medicine, Indianapolis, Indiana Background. The objective of this study was to review our surgical strategy in children with double outlet right ventricle and to assess risk factors for early and late mortality and reoperation. Methods. Patients (n 124; June 1980 to January 2000; age range, 7 days to 16 years; mean, 2.8 years) who underwent repair of double outlet right ventricle. The patients were divided into three groups. Group 1 (n 47) had noncomplex patients with atrioventricular concordance, a single ventricular septal defect, balanced ventricles, no straddling atrioventricular valves, and no major pulmonary artery anomalies. Group 2 (n 39) included patients with double outlet right ventricle and a subpulmonary ventricular septal defect (Taussig-Bing). Group 3 (n 38) had patients with complex anomalies including straddling atrioventricular valves, atrioventricular septal defects or a hypoplastic valve or ventricle, or a combination of atrioventricular septal defects and hypoplastic valve or ventricle. Results. Four types of definitive repairs were performed: (1) intraventricular tunnel repair with a baffle from the left ventricle to the aorta (n 53); (2) use of a valved or nonvalved conduit (n 20); (3) arterial switch operation with a patch committing the left ventricle to the neo-aorta (n 16); and (4) cavopulmonary shunt and Fontan procedures (n 33). Two patients with late postoperative cardiomyopathy had heart transplantation. Potential risk factors included location of the largest ventricular septal defect, presence of additional ventricular septal defects, ventricular outflow obstruction or hypoplasia, or both ventricular outflow obstruction and hypoplasia, previous palliation, and type of definitive operation. There were six early deaths (4.8%) and four late deaths (3.2%), and two heart transplants (1.6%). Overall 15-year survival was 95.8%, 89.7%, and 89.5% for groups 1, 2, and 3, respectively (p 0.08). Thirteen patients (11.4%) have required 15 reoperations. Mean follow-up for survivors was months. Up-todate follow-ups are available on 114 surviving patients. Ninety-five of these patients (83.3%) were in New York Heart Association class I, and the remaining 19 patients (16.7%) were in New York Heart Association class II. Freedom from reoperation was 87%, 72%, and 100% at 15 years for groups 1, 2, and 3, respectively (p 0.11). Conclusions. Survival was high for all patients with double outlet right ventricle undergoing intraventricular tunnel repair, arterial switch operation, and repair with a conduit or a modified Fontan procedure. Careful attention to preoperative anatomy dictates the best surgical approach and will enhance outcomes. (Ann Thorac Surg 2001;72:1630 5) 2001 by The Society of Thoracic Surgeons Double outlet right ventricle (DORV) is a congenital anomaly in which both the aorta and the pulmonary artery originate from the right ventricle. The only outlet from the left ventricle is a ventricular septal defect (VSD). Double outlet right ventricle and subpulmonary VSD (Taussig-Bing anomaly) hearts are considered a subset of DORV unless the pulmonary artery arises predominately from the left ventricle. If so, they are then considered a subset of transposition of the great arteries with VSD [1, 2]. Occasionally, DORV is associated with discordant [3], univentricular [4] or atrioventricular (AV) connections, AV valve atresia, or atrial isomerism [5]. Presented at the Forty-seventh Annual Meeting of the Southern Thoracic Surgical Association, Marco Island, FL, Nov 9 11, Address reprint request to Dr Brown, Section of Cardiothoracic Surgery, Indiana University School of Medicine, 545 Barnhill Dr, EH 215, Indianapolis, IN ; jobrown@iupui.edu. In 1964, Kirklin and colleagues [6] reported successful correction in a child with DORV, subaortic VSD, and concordant AV connections. Since then, complete correction through the use of a variety of surgical techniques has been achieved in more complex forms of DORV. Early reports of successful surgical repair of the Taussig-Bing anomaly were reported by Daicoff and Kirklin [7] in Modified Fontan procedures were advocated when biventricular DORV repair was either impractical or extremely complex [5]. With the improving short-term and medium-term outcome for Fontan procedures in recent years [8, 9], this approach might also be extended to patients who are at increased operative risk with a conventional biventricular repair. This report reviews the anatomical findings, surgical strategies, and results among patients with DORV presenting for operations at the Riley Children s Hospital at the Indiana University Medical Center (Indianapolis, IN) over a 20-year period by The Society of Thoracic Surgeons /01/$20.00 Published by Elsevier Science Inc PII S (01)03079-X

2 Ann Thorac Surg BROWN ET AL 2001;72: DOUBLE OUTLET RIGHT VENTRICLE REPAIR 1631 Table 1. Ventricular Septal Defect Location by Groups and Types of Operation Type of Operation Groups Ventricular Septal Defect Location ITR ASO CR FTO HT Subaortic ventricular septal defect Subpulmonary ventricular septal defect Atrioventricular septal defect Noncommitted ventricular septal defect Double committed ventricular septal defect Multiple ventricular septal defect (subaortic or subpulmonary plus perimembranous) Total ASO arterial switch operation; CR conduit repair; FTO Fontan-type operation; HT heart transplantation; ITR intraventricular tunnel repair. Material and Methods From June 1980 to January 2000, 124 children, (age range, 7 days to 16 years; mean age, 2.8 years) underwent repair of DORV. There were 56 males and 68 females. A diagnosis of DORV was made if both great arteries originated predominantly from the right ventricle with application of the 50% rule, which requires one great artery to arise completely and the other more than 50% from the right ventricle. The diagnosis and anatomic findings were based on a combination of angiography, echocardiography, and surgical inspection. Noncomplex patients (group 1; n 47) had AV concordance, a single VSD, balanced ventricles, no straddling AV valves, and no major pulmonary artery (PA) anomalies. Group 2 patients (n 39) had DORV and subpulmonary VSD (Taussig-Bing anomaly). Group 3 patients (n 38) had complex anomalies including straddling AV valves, AV septal defects or hypoplastic valve or ventricle, or a combination of AV septal defects and hypoplastic valve or ventricle, atrial isomerism, multiple VSDs, and major pulmonary artery anomalies including pulmonary atresia, pulmonary artery sling, or discontinuous branch pulmonary arteries. Sixteen patients with only palliative procedures to date were excluded from this study since they have not yet undergone repair because of age and size. Ninety-three of 124 patients (75%) had a palliative procedure preceding complete repair. Of these, 68 of 93 patients (73%) required only one palliative procedure, 18 patients had two procedures, 6 patients had three procedures, and 1 patient required four palliative procedures. There were no significant differences in the incidences of palliative procedures before definitive operations between patient groups. Most patients were symptomatic and cyanotic. Twelve patients were assigned to New York Heart Association class I, 64 patients to New York Heart Association class II, and 48 patients to New York Heart Association class III and IV. The hemoglobin values ranged from 13 to 23 g/dl (mean, 18.8 g/dl), and the arterial oxygen saturation values ranged from 76% to 93% (mean, 81.6%). Of the 38 patients in group 3 (30%), the most commonly present complex anatomic feature was the presence of a hypoplastic right or left ventricle (n 18), anomalous systemic venous return (n 17), AV septal defect (n 11), mitral valve atresia or stenosis (n 10), atrial isomerism (n 7), straddling AV valves (n 6), anomalous pulmonary venous return (n 6), additional VSDs (n 5), juxtaposed atrial appendages on the left side (n 2), and situs inversus (n 2). The location of the primary VSD and the presence of additional VSDs are shown in Table 1. Of the 57 patients with a subaortic VSD, 28 patients had tetralogy of Fallot anatomy. A subpulmonary VSD was present in 39 patients, and 1 patient had an additional perimembranous defect. The primary VSD was not committed to either outflow tract in 5 patients (noncommitted). This designation was used in all patients whose VSD was anatomically distant from both arterial valves and was not related more directly to one outflow tract than the other. An additional 17 patients had AV septal defects. In 6 patients the VSD was committed to both outflow tracts. There was no statistical difference in the primary VSD location between patients in group 1 and group 3. In 2 patients the subaortic VSD was restrictive. Pulmonary outflow tract obstruction including pulmonary atresia was present in 65 patients and was most prevalent in the group with subaortic VSDs. Two of 5 children (40%) children with noncommitted VSD had pulmonary outflow tract obstruction, as did 2 of 6 patients (33.3%) with doubly committed subarterial defects and 6 of 17 patients with AV septal defects (35%). Only 12 of 38 patients (31%) with subpulmonary VSD had valvar or infundibular pulmonary stenosis or atresia. Aortic and subaortic stenosis was seen in 6 patients (5%; 2 patients from group 1 and 4 patients from group 3). Overall aortic arch obstruction (aortic coarctation or interruption) occurred in 12 patients (9.7%; 8 patients that had complex anatomy from group 3, and 4 patients that had Taussig- Bing complex from group 2). Statistical Analysis The SPSS statistical program for Windows, version 10 (SPSS, Inc, Chicago, IL) was used to perform data analysis. Data are expressed as mean standard deviation and range. The Kaplan-Meier product limit method and Cox proportional hazards regression methods were used for actuarial survival analysis and analysis of freedom from reoperation. Multiple regression analysis was performed as conditional backward stepwise proportional hazards regression. The p values of less than or equal to 0.05 were considered significant.

3 1632 BROWN ET AL Ann Thorac Surg DOUBLE OUTLET RIGHT VENTRICLE REPAIR 2001;72: Fig 1. Operative procedures and reoperations in patients with double outlet right ventricle. (GT Gore-Tex [W. L. Gore & Assoc, Flagstaff, AZ]; PA pulmonary artery; VSD ventricular septal defect.) Operative Data All patients were operated on with standard cardiopulmonary bypass, bicaval cannulation, and moderate hypothermia with cold potassium cardioplegic arrest. A total of 124 patients who underwent surgical procedures using the Dacron patch and polypropylene (Ethicon, Johnson & Johnson, Somerville, NJ) sutures comprised the study population. Figure 1 showed the operative procedures. Four types of definitive repairs were performed: (1) intraventricular tunnel repair with a baffle from the left ventricle to the aorta, (2) use of a valved or nonvalved conduit, (3) arterial switch operation with a patch committing the left ventricle to the pulmonary artery (neo-aorta), and (4) cavopulmonary shunt and Fontan procedures including bidirectional cavopulmonary connection, modified Fontan procedures, total cavopulmonary connection, and the Kawashima modification of the Fontan operation (Table 2). Two patients who developed cardiomyopathy had heart transplantation. One hundred twenty-four patients have undergone definitive operations. In 89 patients (72%) a biventricular repair was accomplished with an intraventricular tunnel in 53 patients, a conduit in 20 patients, or an arterial switch operation in 16 patients. Thirty-three patients had one or more modified Fontan-type procedures (Table 3). Fifteen patients had a fenestration (2.5 mm) placed in the baffle. In group 2, the arterial switch operation was done Table 2. Type of Operation Type of Operation Group 1 Group 2 Group 3 Intraventricular tunnel repair Arterial switch operation Conduit repair Fontan type procedure Heart transplantation Total at a significantly younger age than the intraventricular tunnel baffle operation ( years vs years; p 0.05), the conduit repair ( years; p 0.03), and the Fontan-type procedures ( years; p 0.007). Conventional intraventricular tunnel repair was the preferred surgical approach whenever possible; 53 patients (43%) underwent intraventricular tunnel repair in the present series; ten of these patients (19%) were performed by a right atrial approach and required no right ventricular outflow patch. The remaining 43 patients (81%) received an outflow patch at the time of intraventricular tunnel repair through a right ventriculotomy. Ten of these patches (23%) were transannular. Since 1986 the arterial switch operation with VSD-topulmonary artery baffle was performed in 16 patients (13%) with Taussig-Bing anomaly. All of these patients had a subpulmonary VSD (group 2). The LeCompte maneuver was performed on all but 1 patient from the arterial switch operation group. Table 3. Cavopulmonary Shunts and Modified Fontan Procedures Procedures No. of Patients Fontan (total cavopulmonary connection) 8 (7 a ) Hemi-Fontan/Fontan (total cavopulmonary connection) 8(6 a ) Bidirection Glenn shunt 6 Bilateral bidirection Glenn shunt 2 Hemi-Fontan 2 Bilateral bidirection Glenn shunt/extracardiac Fontan 2 Bidirection Glenn shunt/fontan (total cavopulmonary connection) 2(2 a ) Kawashima modification of Fontan procedure and Hemi-Fontan 2 Fontan (right ventricle and pulmonary artery) 1 Total 33 a Patients with fenestration.

4 Ann Thorac Surg BROWN ET AL 2001;72: DOUBLE OUTLET RIGHT VENTRICLE REPAIR 1633 Table 4. Indication of Early and Late Mortality Early Deaths Late Deaths Groups Groups Low cardiac output Massive cerebral bleeding Unexplained or unknown Sepsis A VSD-to-aorta baffle accompanied by external right ventricle to pulmonary artery conduit (conduit repair) was performed in 20 patients (16%). Thirteen of these had Taussig-Bing anomaly with severe valvular and supravalvular pulmonary stenosis created by a previous pulmonary artery band. A Damus-Kaye-Stansel operation was performed in 4 patients. Indication for this repair included a hypoplastic aortic annulus in 2 patients, abnormal coronary artery pattern precluding the LeCompte maneuver in one, and severe proximal pulmonary trunk distortion after pulmonary banding accompanied by marked subaortic stenosis in 1 patient. Two patients with a Damus-Kaye-Stansel connection had the VSD baffled to the aorta, and in the other 2 patients the Damus-Kaye-Stansel connection was done before a Fontan operation. The VSD was restrictive on preoperative studies in 2 patients (1.6%). However, VSD enlargement with resection of the conal septum was performed in an additional 14 cases (11%) to improve baffle geometry or reduce the potential for late residual transseptal obstruction. Thus, the conal septum was partially resected in 16 patients (13%) to reduce the potential for subarterial stenosis and to improve baffle geometry by allowing a more direct route from the VSD to the semilunar valve. Results Early Mortality Table 4 summarizes the details of six hospital deaths (4.8%). A significantly higher proportion of group 3 patients died early after repair (3 of 38; 7.9%) than those patients in group 1 (1 of 47; 2.1%; p 0.05). Table 5 presents the results of univariate and multivariate risk factor analysis for early mortality of the potential risk factors analyzed in all 124 patients, only atrioventricular septal defect and aortic arch obstruction reached near significance in univariate analysis and were significant risk factors in multivariate analysis. Late Mortality There were four late deaths; two in group 2, and one in each of the other groups at a mean follow-up time of years. Two of the 4 patients from group 2 had undergone conduit repair, 1 patient had undergone intraventricular tunnel repair, and 1 patient had a Fontantype (Hemi-Fontan) procedure (Table 4). Figure 2 shows the overall actuarial survival, including operative mortality, which was 95.8%, 89.7%, and 89.5% at 15 years in patients in groups 1, 2, and 3, respectively. Reoperations and Follow-up Follow-up information was available in 114 surviving patients. Patients were followed up to a mean of months (range, 6 months to 16 years). During the period of follow-up, 13 patients underwent 15 reoperations at a mean time interval of years (range, 6 months to 15 years) after definitive repair. Of these, 4 patients were from group 1, and 9 patients were from group 2. The initial anatomic features and type of reoperation are summarized in Table 5. Risk factor analysis for reoperation showed no statistical significant variables associated with reoperation (Table 6). The estimated freedom from reoperation at 15 years was 87%, 72%, and 100% in patients in groups 1, 2, and 3 (Fig 3). Additionally, 4 patients underwent pacemaker implantation for postoperative complete heart block (2 patients from group 1 and 2 patients from group 3). Of the 114 patients available for long-term follow-up, 95 patients (83%) were in New York Heart Association class I, and 19 patients (17%) were in New York Heart Association class II. Twenty-one patients had mild residual right ventricular outflow tract obstruction (gradient 20 mm Hg). Residual left ventricular outflow tract obstruction was present in 3 patients. In 2 of these patients it was considered mild and in 1 patient it was moderate. Comment This study confirms that a biventricular repair can be achieved in the majority of patients with DORV with acceptably low perioperative mortality. Previous reviews Table 5. Reoperation (n 15) in 13 Patients Reoperation Group 1 Group 2 Group 3 Pulmonary artery conduit replacement Right ventricular outflow tract obstruction reconstruction Heart transplantation Aortic annuloplasty Residual ventricular septal defect closure Total 5 (12.2%) 10 (27.8%)... Fig 2. Actuarial patient survival, including operative mortality in patients with double outlet right ventricle.

5 1634 BROWN ET AL Ann Thorac Surg DOUBLE OUTLET RIGHT VENTRICLE REPAIR 2001;72: Table 6. Risk Factors Analysis Risk Factors p Value a Risk Factors p Value a Age at operation Not significant Previous palliation Not significant Type of repair Not significant Weight at repair median Not significant Resection of conus Not significant Pulmonary outflow procedure Not significant Location of ventricular septal defect Not significant Ventricular septal defect enlargement Not significant Atrioventricular septal defect 0.04 b Multiple ventricular septal defects Not significant Great artery relationship Not significant Pulmonary stenosis Not significant Aortic arch obstruction 0.05 b Aortic stenosis Not significant a Univariate analysis. b Significant in multivariate analysis. Fig 3. Actuarial freedom from reoperation in patients with double outlet right ventricle. have reported hospital mortality figures of up to 25%, especially in patients with noncommitted or subpulmonary VSDs [2, 10]. Since 1980, new surgical techniques including the arterial switch operation have significantly improved the outcome in complex forms of DORV [11, 12]. This review shows a nonsignificant higher risk in patients with noncommitted, subpulmonary, or atrioventricular septal defects [2, 13]. In our institution, the arterial switch operation is now the procedure of choice for patients with subpulmonary VSD without significant right ventricular outflow obstruction, as well as with other patients in which baffling from the left ventricle to the pulmonary artery is technically easier than baffling to the aorta. In the present study the arterial switch operation for DORV with subpulmonary VSD was associated with low hospital mortality. On the other hand, an intraventricular tunnel repair without arterial switch is performed only on a small number of patients with subpulmonary VSD. When technically possible, this approach has led to good results with low operative mortality and a low necessity for reoperation [12, 14, 15]. Among patients with noncomplex forms of DORV and noncommitted VSD, an intraventricular tunnel repair is still possible in the majority of patients. However, in more than half of such patients, a cavopulmonary shunt or modified Fontan operation was chosen because of associated atrial isomerism with some degree of ventricular imbalance. The association of DORV with AV septal defect has always represented a difficult surgical problem, with a high mortality reported in an extensive clinical pathologic review published in 1975 [16]. Regardless of the position of the VSD, the results for intraventricular repair of DORV with AV septal defect have not been rewarding [17]. Pacifico and associates [17] reported three deaths in 5 patients with this combination, whereas in the overall experience at the University of Alabama [4], there were four hospital deaths in 7 patients who underwent operation. The intraventricular tunnel repair is also a less-thanattractive procedure in patients of DORV with straddling AV valves and criss-cross hearts, either alone or in combination, particularly when hypoplastic right or left ventricles are present [5, 8]. Hypoplasia of right, left, or both ventricles is of obvious surgical significance when an intraventricular tunnel repair of DORV is attempted [1, 3, 4]. The Fontan operation represents an attractive alternative in complex DORV because it overcomes the technical difficulties of creating an intracardiac tunnel in the presence of anomalies of the AV junction. Prosthetic valves are not needed in patients with severe AV straddling, and extra cardiac conduits, often essential for the intracardiac tunnel operation, can be avoided with Fontan type procedures. The Damus-Stancel-Kaye procedure is still of value when transplantation of the coronary arteries is restricted by anatomical factors such as origin of the circumflex artery from the right coronary artery or early branching of the left main coronary artery, which restricts mobility of the left coronary ostium. An additional advantage of the Damus-Stancel-Kaye procedure is that in some situations, such as univentricular heart, in which the Fontan procedure is also being performed, it allows relief of substantial subaortic obstruction without the risk of heart block or recurrent obstruction associated with subaortic resection. The use of a cavopulmonary shunt or modified Fontan procedure has previously been advocated as the surgical procedure of choice in the presence of complex anatomic features such as straddling AV valves or ventricular imbalance. In recent years, surgical modifications with staged procedures and atrial baffle fenestration have been associated with a considerable improvement in the short-term and medium-term results for the Fontan type operation [8, 9]. The difference in early mortality between patients with complicating anatomic features undergoing biventricular repair and those patients undergoing some form of Fontan procedure, strongly suggests that the modified Fontan is the procedure of choice for the complex group.

6 Ann Thorac Surg BROWN ET AL 2001;72: DOUBLE OUTLET RIGHT VENTRICLE REPAIR 1635 References 1. Kirklin JK, Pacifico AD, Kirklin JW. Intraventricular tunnel repair of double outlet right ventricle. J Card Surg 1987;2: Kirklin JW, Pacifico AD, Blackstone EH, Kirklin JK, Bargeron LM Jr. Current risk and protocols for operations for doubleoutlet right ventricle: derivation from an 18-year experience. J Thorac Cardiovasc Surg 1986;92: Tabry IF, McGoon DC, Danielson GK, et al. Surgical management of double-outlet right ventricle associated with atrioventricular discordance. J Thorac Cardiovasc Surg 1978; 76: Kirklin JW, Barratt-Boyes BG. Double-outlet right ventricle. In: Kirklin JW, Barratt-Boyes BG, eds. Cardiac surgery, 2nd ed. New York: Churchill Livingston, 1993: Russo P, Danielson GK, Puga FJ, McGoon DC, Humes R. Modified Fontan procedure for biventricular hears with complex forms of double-outlet right ventricle. Circulation 1988;78(Suppl III):III Kirklin JW, Harp RA, McGoon DC. Surgical treatment of origin of both vessels from right ventricle, including cases of pulmonary stenosis. J Thorac Cardiovasc Surg 1964;48: Daicoff GR, Kirklin JW. Surgical correction of Taussig-Bing malformation. Report of three cases. Am J Cardiol 1967;19: Pearl JM, Laks H, Drinkwater DC, et al. Modified Fontan procedure in patients less than 4 years of age. Circulation 1992;86(Suppl II):II Jacobs ML, Norwood WI Jr. Fontan operation: influence of modifications on morbidity and mortality. Ann Thorac Surg 1994;58: Shen W-K, Holmes DR, Porter C, McGoon DC, Ilstrup DM. Sudden death after repair of double-outlet right ventricle. Circulation 1990;81: Serraf A, Lacour-Gayet F, Bruniaux J, et al. Anatomic repair of Taussig-Bing hearts. Circulation 1991;84(Suppl III): III Aoki M, Forbess JM, Jonas RA, Mayer JE Jr, Castaneda AR. Results of biventricular repair for double outlet right ventricle. J Thorac Cardiovasc Surg 1994;107: Luber JM, Castaneda AR, Lang P, Norwood WI. Repair of double-outlet right ventricle: early and late results. Circulation 1983;68(Suppl II):II Kawashima Y, Matsuda H, Yagihara T, et al. Intraventricular repair for Taussig-Bing Anomaly. J Thorac Cardiovasc Surg 1993;105: Walters HL, Pacifico AD. Double outlet ventricles. In: Mavroudis C and Backer CL, eds. Pediatric cardiac surgery, 2nd edition. St. Louis: Mosby, 1994: Spidaramont S, Feldt RH, Ritter DG, et al. Double-outlet right ventricle associated with persistent common atrioventricular canal. Circulation; 1975;52: Pacifico AD, Kirklin JW, Bargeron LM, Jr. Repair of complete atrioventricular canal associated with tetralogy of Fallot or double-outlet right ventricle: report of 10 patients. Ann Thorac Surg 1980;29: DISCUSSION DR ROSS M. UNGERLEIDER (Portland, OR): John, That is an excellent series. I am impressed by the results, and clearly you have indicated that careful attention to the anatomy and selection of the proper operation can lead to good results. I am curious if you could tell us a little bit more about your patient groups. It seemed interesting that you had such a high number of previous cardiac procedures, which although that might be the case in patients being staged to a Fontan, your numbers also were higher than your Fontan group, and I am wondering if your results indicate that you are staging your patients, even those with correctable anatomy, with palliative operations leading to eventual repair. Could you tell us a little bit about the age at which you are operating on the patients getting intraventricular repair? This is a historical series, but could you share with us your current policies from these experiences? DR BROWN: I think it is a very good question, Ross, and obviously this report is a 20-year review. The mean age at operation for our entire group was about years. In the Boston Children s report, as you know, they had a mean age at operation of around 1 year of age. There is no question that our approach has been more conservative, particularly in the complex group. Some of our patients have had one, two or more palliative procedures prior to conventional repair. This may have decreased our overall mortality. I think the trend is to operate these kids earlier and earlier, particularly the ones with favorable anatomy. Your point is well take. DR W. STEVES RING (Dallas, TX): These are really outstanding results, and one of the things that intrigued me with the results is how few problems with the intraventricular tunnel or baffle that you have had in terms of late obstruction problems or subaortic obstruction, particularly in some of the ones that have, for example, either doubly committed or somewhat remote ventricular septal defect (VSD). Can you tell us a little bit about your technical considerations in the management of these patients and how you manage to prevent this potential problem? DR BROWN: Thanks, Steves. Not shown in this presentation because of the time limitations were 20 patients who required enlargement of their VSD or left ventricular outflow tract (LVOT) pathway. Two or 3 of them had obvious subaortic obstruction preoperatively. In the other 18 or 19 patients, the surgeon determined at the time of repair that the pathway was likely to become obstructed and enlarged the VSD. So we were pretty aggressive about resecting the conal septum to make that pathway as large as we could. DR GEORGE DAICOFF (St. Petersburg, FL): Very nice, John. We are getting a lot of reluctance from cardiologists to do angiograms, and we depended so much on them in the old days. Can you make do with what limited studies you have or do you just use echocardiography? How do you decide, because anatomy seems to be so important in deciding what procedure to do? DR BROWN: Well, George, I have to admit, our excellent group of cardiologists have really given us a better view of the LVOT with echocardiograms than we ever got with angiograms. They are able to show us the proposed LVOT pathways in a number of different views. We base most of our preoperative decisions on the preoperative echocardiograms. Our pediatric cardiologists really help us out a lot in determining the optimal surgical approach. When in question, we obtain a transesophageal echocardiograms before going on bypass, just be sure we understand the relationships between the VSD and the great vessels.