Arterial Switch Operation Surgery Surgical Solutions to Complex Problems

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Pediatric Cardiovascular Arterial Switch Operation Surgery Surgical Solutions to Complex Problems

Tom R. Karl, MS, MD The arterial switch operation is appropriate treatment for most forms of transposition of Andrew Cochrane, FRACS the great arteries. In this review we analyze indications, techniques, and outcome for Christian P.R. Brizard, MD various subsets of patients with transposition of the great arteries, including those with an intact septum beyond 21 days of age, intramural coronary arteries, aortic arch obstruction, the Taussig-Bing anomaly, discordant (corrected) transposition, transposition of the great arteries with left ventricular outflow tract obstruction, and univentricular hearts with transposition of the great arteries and subaortic stenosis. (Tex Heart Inst J 1997;24:322-33)

T ransposition of the great arteries (TGA) is a prototypical lesion for pediatric cardiac surgeons, a lethal malformation that can often be converted (with a single operation) to a nearly normal heart. The arterial switch operation (ASO) has evolved to become the treatment of choice for most forms of TGA, and success with this operation has become a standard by which pediatric cardiac surgical units are judged. This is appropriate, because without expertise in neonatal anesthetic management, perfusion, intensive care, cardiology, and surgery, consistently good results are impossible to achieve. Surgical Anatomy of TGA In the broad sense, the term "TGA" describes any heart with a discordant ventriculoatrial (VA) connection (aorta from right ventricle, pulmonary artery from left ventricle). The anatomic diagnosis is further defined by the intracardiac features. Most frequently, TGA is used to describe the solitus/concordant/discordant heart. A heart with an additional discordant atrioventricular (AV) connection is termed "congenitally corrected" or "discordant" TGA. The Taussig-Bing anomaly is a double-outlet right ventricle with a subpulmonic ventricular septal defect (VSD). Strictly speaking, a heart with a double-outlet right ventricle does not have TGA, because 1 VA connection is concordant. However, anatomically and physiologically, the Taussig-Bing anomaly closely resembles TGA with a VSD and is Section editor: appropriately included in this discussion.' Transposition of the great arteries may Timothy F Feltes, MD also describe hearts with a univentricular AV connection (e.g., double-inlet left ventricle, tricuspid atresia) if an outlet chamber of right ventricular morphology Key words: Coronary vessel anomalies/surgery; heart gives rise to the aorta. The "TGA family" is illustrated in Figure 1. defects, congenital/surgery; Although the orientation of the great arteries varies considerably in TGA, a heart surgery/methods; nearly constant feature is that the coronary arteries arise from the aortic sinuses infant; infant, newborn; transposition of great that face the pulmonary artery, which greatly facilitates an ASO.2 The extraaortic vessels/surgery; vascular course of the coronary arteries is variable (Fig. 2), and the origin of 1 or both surgery/methods vessels may rarely be intramural and stenotic, posing special problems for the surgeon during an ASO.3'4 From: The Cardiac Surgical Unit, Royal Diagnosis of TGA Children's Hospital, Melbourne, Australia The diagnosis of TGA could be considered in any cyanotic newborn, but elec- trocardiogram, chest x-ray, and physical examination are not diagnostic. Two- dimensional echocardiography usually provides rapid and complete noninvasive Address for reprints: Tom R. Karl, MS, MD, diagnosis, so in the neonate, cardiac catheterization is rarely necessary. A weak Director, Victorian Pediatric area in imaging is the proximal coronary arteries, which may be difficult to accu- Cardiac Surgical Unit, rately describe with echocardiography or angiography.4 Prenatal echocardiographic Royal Children's Hospital, Flemington Road, Parkville diagnosis of TGA is now possible as well, although treatment remains problem- VIC 3052, Australia atic.5

322 Arterial Switch Volume 24, Number 4, 1997 ccTGA.IVS ccTGA.VSD (+l-LVOTO)

Fig. 1 The transposition of the great arteries "family, " which includes all hearts with a discordant ventriculoarterial connection as well as the Taussig-Bing anomaly (double-outlet right ventricle and subpulmonic ventricular septal defect). AAO = aortic arch obstruction; Ao = aorta; AV = atrioventricular; cc = congenitally corrected; DORV = double-outlet right ventricle; IVS = intact ventricular septum; LVOTO = left ventricular outflow tract obstruction; RV = right ventricle; SAS = subaortic stenosis; Sub-PA = sub-pulmonary artery; TGA = transposition of the great arteries; VA = ventriculoarterial; VSD = ventricular septal defect

Physiology and Natural History ent to maintain left ventricular pressure at system- The central physiologic problem is arterial hemoglo- ic levels. Therefore the optimal time for an ASO is bin desaturation, the severity of which varies with within the 1st 2 weeks of life, to avoid a "decondi- the degree of communication between the parallel tioned" left ventricle, which may contribute to low systemic and pulmonary circulations. The neonatal cardiac output postoperatively.6 Infants with TGA presentation varies from a healthy-appearing baby and arch obstruction (as well as other prostaglandin- to complete cardiovascular collapse. At the worst E1-dependent patients) usually require operation end of the clinical spectrum are those babies with a within the 1st few days of life.7 In TGA with a VSD, restrictive atrial septal defect (ASD) and/or aortic elective operation can usually be carried out at 1 to arch obstruction, who are often profoundly hypox- 3 months of age, if clinical condition remains stable. emic and acidotic. The natural history of all forms of TGA is ex- Surgery for TGA tremely unfavorable, and without some form of pal- The ASO has emerged as the procedure of choice for liative or definitive surgery, most neonates would most babies with TGA. The procedure employed at not survive infancy. In nearly all cases, the initial re- the Royal Children's Hospital (RCH) is technically suscitation efforts should include balloon atrial sep- demanding but logical and reproducible. It is a hy- tostomy, irrespective of surgical plan. brid of techniques proposed by Jatene, Lecompte, Timing of operation is critical, especially for ba- Quaegebeur, Mee, and others.2'84" The general tech- bies with TGA and an intact ventricular septum nique will be described briefly, along with modifi- (IVS). After the baby is born, pulmonary vascular cations that solve specific problems encountered in resistance drops from its fetal (systemic) level to a special cases. normal postnatal level within 2 weeks. This decline Our cardiopulmonary bypass strategy employs a is accompanied by an involution of left ventricular fresh, heparinized (noncitrate) blood prime and a mass, unless a patent ductus arteriosus, VSD, or left hollow fiber or membrane oxygenator.2 Alphastat ventricular outflow tract obstruction (LVOTO) is pres- pH strategy is followed for cooling to 26 to 28 'C. In

Texas Heart InstituteJournal Arterial Switch 323 Sinus 2 (Left hand facing)

Leiden 1 LCx-2R Leiden 1 Cx-2LR Yacoub A

LAD LAD Cx B

I - R o* I L

A RCA RCA Leiden 1 R-2LCx Leiden 1 LR-2Cx Yacoub E Fig. 2 The Leiden classification of coronary anatomy in transposition of the great arteries. The right hand of an observer standing in the noncoronary sinus (facing the coronary ostia) points to sinus 1, the left hand to sinus 2. The most common pattern is 1 left, circumflex, 2 right. Ao = aorta; Cx = circumflex coronary artery; L = left; LAD = left anterior descending coronary artery; PA = pulmonary artery; R = right; RCA = right coronary artery (From: Karl TR. Transposition of the great arteries.2 Reproduced by permission of Mosby-Year Book, Inc.) most cases, full-flow cardiopulmonary bypass (150 aortic and bicaval cannulation and left-heart venting to 250 ml/kg) is used for the entire operation, with through the ASD. We use cold crystalloid cardiople-

324 Arterial Switch Volume 24, Number 4, 1997 gic solution and topical cold saline for myocardial pro- monary artery. The mobilized coronary arteries are tection, although many units use sanguineous car- translocated and sutured in place with running 8-0 dioplegic solution with good results. polypropylene sutures. We employ the Lecompte With the heart arrested, the aorta and pulmonary maneuver9 in nearly all cases, including those with artery are transected just above the commissures side-by-side great vessels.9" 2 The neoaortic anasto- (Fig. 3). The coronary arteries are excised with a mosis is completed by gathering tissue on the proxi- large cuff of sinus tissue, and medially based rectan- mal side to match the vessel sizes. At this point the gular flaps are cut into the facing sinuses of the pul- VSD, if present, is closed directly with pledgeted mat-

Neopulmonary a.

Fig. 3 The arterial switch operation technique used at Royal Children's Hospital. We employ medially based rectangular flaps in the neoaortic sinuses for coronary translocation. The flaps decrease the arc of rotation and prevent tension on the anastomosis. Ao = aorta; LCA = left coronary artery; PA = pulmonary artery; RCA = right coronary artery (From: Karl TR. Transposition of the great arteries.2 Reproduced by permission of Mosby-Year Book, Inc.)

Texas Heart InstituteJournal Arterial Switch 325 tress sutures and a Dacron patch, and the heart is tially suitable for an ASO, although some are more deaired. With the aortic clamp off, the neopulmon- problematic than others from a technical point of ary sinus defects are repaired with individual autolo- view. In our experience with more than 400 ASOs, goUs pericardial patches, extended posteriorly to only 1 patient was considered unsuitable because of lengthen the pulmonary artery. The neopulmonary coronary anatomy (a premature infant with bilateral anastomosis is completed, and the patient is then intramural branching of a single coronary artery, warmed to 37 °C and separated from cardiopulmo- coursing between the aorta and the pulmonary ar- nary bypass. Left atrial and pulmonary artery lines tery). An intramural coronary artery (IMCA) was and a peritoneal dialysis catheter are used in all noted in 5% of infants undergoing an ASO in our cases. Postoperative care is aimed at prevention of institution (Fig. 4); the natural history of an IMCA in excessive afterload and fluid administration, as left TGA is unknown, but there is an association of this ventricular contractility may be impaired for several type of coronary anatomy with sudden death in con- days, especially in older babies with TGA and an cordant hearts. IVS. Details of postoperative management are be- In infants with an IMCA, the arterial switch tech- yond the scope of this review and are described else- nique must be modified.4 Following aortic tran- where.2'6 section, an IMCA should be suspected if there is an eccentrically placed, small, or apparently single os- Special Problems tium or a vessel rising above a valve commissure. To A number of anatomic and physiologic TGA subsets mobilize and translocate this type of vessel safely, require special consideration. the posterior aortic valve commissure must be de- The Older Baby with TGA and an IVS. Beyond 2 tached (Fig. 5). The ostium is then cut back to en- weeks of age, left ventricular involution has usually large it and move it laterally. The coronary arteries begun, and therefore concerns are raised regarding are excised as a large cuff that can be divided and postoperative contractility. An early ASO study us- translocated as described above. This technique ing pooled Congenital Heart Surgeons' Society data leaves a single large defect in the neopulmonary ar- suggested that the risk of an ASO increased beyond tery that can be repaired with 1 pericardial patch. 7 days of age.'" This result led many centers to adopt The commissure is then resuspended to the patch a 2-stage approach for children beyond 2 to 3 weeks with interrupted sutures to reconstruct the neopul- of age, especially those with subnormal calculated monary valve, and the operation is completed as de- left ventricular mass or wall thickness.'4 We have scribed above. taken a different approach, offering a primary ASO TGA with a LVOTO. Left ventricular outflow tract to all children up to 8 weeks of age (and selectively obstruction is found in 20% of infants with TGA and to older children as well), irrespective of left ven- in most cases is a contraindication for an ASO. In tricular pressure, geometry, or mass.6 Rapid left ven- such patients, alternate strategies can be employed tricular hypertrophy has been documented in the (Fig. 6), but the long-term results may be less satis- early postoperative period.6 Infants with TGA and an IVS presenting between 8 weeks and 6 months of age are best treated with a 2-stage ASO strategy.6"15"16 The capacity of the left ventricle to respond to a pressure load with hypertrophy in this age group makes rapid retraining (less than 2 weeks) possible. The 1st stage is transsternal pulmonary artery (PA) band placement, accompanied by a 4-mm polytetrafluoroethylene innominate artery-to-right pulmonary artery shunt to maintain oxygenation. Temporary low cardiac output following this procedure is common, but within 7 to 10 days the left ventricular pressure and mass will usually be adequate to enable an ASO without severe low cardiac output postoperatively. Within this time frame, adhesions are generally not too troublesome at re- Fig. 4 Intramural left coronary artery shown in a cross- and the ASO sectional echocardiogram. The ostium is eccentrically placed sternotomy, (with simple debanding and frequently stenotic. This pattern is seen in approximately and shunt division) can be performed as described 5% of cases of transposition of the great arteries and creates above. In older patients, a more prolonged period technical problems for excision. of left ventricular conditioning is usually required.17 Ao = aorta; IMCA = intramural coronary artery; Coronary Artery Abnormalities. We would con- PA = pulmonary artery sider virtually all coronary artery variations poten-

.3262llumeArterial Switch 24, Number 4, 1997 factory than those with an ASO. However, a minor- such as accessory AV valve or endocardial cushion ity of patients may have a resectable type of LVOTO, tissue, fibrous subvalvar membranes, and anomalous muscle bundles (Fig. 6),18 and the final decision regarding resectability must often be made intraop- eratively. Resection is performed via the transected pulmonary artery, combined with exposure through the tricuspid valve if necessary. Structures at risk during resection include the neoaortic valve, the

D E Fig. 5 Technique for mobilization and translocation of an intramural coronary artery. The posterior aortic commissure is detached to provide sinus tissue for coronary excision. The ostium is cut back to enlarge and move it laterally The commissure is resuspended from the pericardial patch. (From: Mee, R. The arterial switch operation. In: Stark J, de Leval M, editors. Surgery for congenital heart defects. Philadelphia: W.B. Saunders Company, 1994:483-500. Reproduced by permission of W.B. Saunders Company.)

TGA with LVOTO Surgical Options I I I Intact Ventricular Septum Ventricular Septal Defect

Senning +/- Resection Rastelli Operation

Senning + LV-PA Conduit Nikaidoh - Bex Operation

REV ASO + Resection I ASO + Resection I Fig. 6 Possible surgical strategies for transposition of the great arteries with left ventricular outflow tract obstruction (LVOTO). In cases with resectable forms of LVOTO, the arterial switch operation may still be the best option. ASO = arterial switch operation; LV = left ventricle; PA = pulmonary artery; REV = r6paration a l'6tage ventriculaire; TGA = transposition of the great arteries

Texas Heart InstituteJournal Arterial Switch 327 coronary branches, and conduction tissue. Sustained The Taussig-Bing Anomaly. Defining this entity relief of obstruction can be expected in properly se- has created more problems for the anatomist than for lected cases (Fig. 7). the surgeon. Certainly there is some overlap be- TGA with Aortic Arch Obstruction. Aortic arch tween double-outlet right ventricle with an uncom- obstruction, rare in TGA with an IVS, complicates mitted VSD, Taussig-Bing anomaly, and TGA with a 7% to 10% of cases ofTGA with a VSD and a Taussig- VSD. For surgical purposes, however, the key ques- Bing anomaly.'2 The obstruction is most commonly tion in a double-outlet right ventricle is whether the a discrete coarctation with a hypoplastic transverse left ventricle can be connected more directly to the arch and isthmus.19'20 A complete interruption is aorta via an intraventricular tunnel or to the pulmo- more likely to occur in the univentricular heart with nary artery. A number of operations have been em- TGA and subaortic stenosis.7'21 For all types of ployed for the latter situation, including atrial-level TGA with arch obstruction, closure of the ductus can and intraventricular repairs without an ASO (Fig. 9). precipitate profound cardiovascular collapse in the Our strong preference, however, is the ASO, per- neonate. The risk of necrotizing enterocolitis and in- formed within the 1st 3 months of life.12 The surgeon traventricular hemorrhage is also higher than in should be aware that Taussig-Bing hearts are more other forms of TGA. Most patients with TGA and likely to have atypical coronary anatomy, side-by- arch obstruction should have a 1-stage neonatal re- side great vessels, and aortic arch obstruction when pair via median sternotomy.7'21 compared with other TGA variants. The ASO is per- For arch repair, 2 arterial perfusion cannulae are formed as it is for TGA with a VSD, with a transatrial placed, 1 in the ascending aorta and the other in the approach for placement of a left ventricle-pulmonary ductus (Fig. 8), which is proximally ligated. The pa- artery baffle. Exposure through the tricuspid valve tient is cooled to 18 °C, the circulation is arrested, is usually quite adequate, and pledgeted individual and snares are placed to occlude the head vessels. sutures can be placed around the subpulmonic co- The descending aorta is transected just beyond the nus and through the septal tricuspid valve leaflet. A duct insertion and anastomosed to the ascending aor- large Dacron patch is used for septation in order to ta at the base of the innominate artery (Fig. 8). The achieve an unobstructed pathway to the neoaorta, arterial switch is then completed as described above. which has a biventricular origin, overriding the VSD.

LV - arterial pressure, mmHg 100

0 Preoperative (med = 50) Last follow-up (med = 0) Fig. 7 Pre- and postoperative left ventricular outflow tract gradients for patients undergoing arterial switch operation in the presence of left ventricular outflow tract obstruction. There has been good relief of the gradient. LV = left ventricle

328 Arterial Switch Volume 24, Number 4, 1997 The neopulmonary artery anastomosis can be con- structed on a branch pulmonary artery, closing a portion of the distal main pulmonary artery to com- pensate for a side-by-side vessel position. In an oc- casional patient, pulmonary artery reconstruction without using the Lecompte maneuver may be better.'2 Discordant TGA. "Classical" repairs (i.e., simple septation with or without a left ventricle-to-pulmonary artery conduit) of discordant (congenitally corrected) TGA leave a discordant AV and VA connection (Fig. 10). The long-term outlook is suboptimal due to progressive tricuspid insufficiency and right ventricular dysfunction in a significant proportion of patients.21'22 As an alternative, patients with congenitally corrected TGA can be considered for the Senning23 procedure together with an ASO, if they meet the following criteria22: 1) unobstructed left ventricle-to- pulmonary artery and right ventricle-to-aorta connections (with or without surgical revision); 2) balanced ventricular and AV valve sizes; 3) a septatable heart, without major AV valve straddling; 4) translocatable coronary arteries; 5) a current (or recent) left ventricular/right ventricular pressure ratio less than 0.7; and 6) a competent mitral valve with good left ven- Fig. 8 Cannulation setup and repair technique for repair of tricular function. aortic arch in transposition of the great arteries. Circulatory arrest is used for arch repair, with anastomosis of the The majority of children with discordant TGA will descending aorta opposite the innominate artery The therefore be excluded from the Senning-plus-ASO Lecompte maneuver releases tension on the repaired arch. strategy by virtue of LVOTO, and they are best treated Ao = aorta; PA = pulmonary artery; PDA = patent ductus with the Senning technique together with a Rastelli arteriosus operation24 or a Fontan procedure.22 Newborns with- (From: Karl TR. Transposition of the great arteries.2 Repro- out LVOTO can be palliated justifiably with a PA duced by permission of Mosby-Year Book, Inc.) band, deferring this complex and somewhat lengthy operation to approximately 1 year of age.

Surgical Options in Taussig Bing Anomaly

Taussig Bing Repair VSD Closure

I LV to PA LV to Ao Connection Connection

- Arterial Switch - Kawashima

- Senning/Mustard - REV (Lecompte)

I..-Damus Kaye Stansel Fig. 9 Possible operative strategies for the Taussig-Bing anomaly. We prefer the arterial switch operation for most patients with this transposition of the great arteries (TGA) variant. Aortic arch obstruction, side-by-side vessels, and coronary anomalies occur with higher frequency than in other TGA variants. Ao = aorta; LV = left ventricle; PA = pulmonary artery; REV = r6paration a l'6tage ventriculaire; VSD = ventricular septal defect

Texas Heart InstituteJournal Arterial Switch 329 Fig. 10 A) "Classical" septation of a heart with discordant transposition of the great arteries, leaving the right ventricle and tricuspid valve in the systemic circuit. B) The Senning technique plus an arterial switch operation restores concordant atrioventricular and ventriculoatrial connections, avoiding late problems attributable to a right ventricle in the systemic circuit. Ao = aorta; LA = left atrium; LV = left ventricle; PA = pulmonary artery; RA = right atrium; RV = right ventricle

The operation proceeds in the manner of an ASO unobstructed left ventricular outlet to the neoaorta.21 in TGA with an IVS, up to the point of ASD repair. As most patients will also have arch obstruction, an The VSD is closed via the mitral valve, with sutures arch repair is performed concurrently. The operation on the right ventricular side of the septum to avoid is technically identical to that described above for heart block. The atrium is then septated according TGA with arch obstruction, except that an atrial sep- to the Senning technique.25 tectomy is performed rather than ASD closure. He- ASO for Univentricular Anatomy. Infants with moglobin saturation after cardiopulmonary bypass double-inlet left ventricle or tricuspid atresia can be should range from 70% to 80%. Some patients will considered to have TGA if the aorta rises from an need augmentation of pulmonary blood flow with outlet chamber of right ventricular morphology. The a modified Blalock-Taussig shunt, because the VSD systemic blood flow in such infants is regulated by a continues to close during the postoperative period muscular VSD (or bulboventricular foramen), which (weeks to months). Early conversion to a bidirec- has a strong tendency toward spontaneous closure. tional cavopulmonary shunt is advisable as either a The resulting subaortic stenosis may evolve sponta- definitive procedure or a step toward the Fontan neously, or more rapidly following PA banding. In procedure in suitable candidates. newborns with arch obstruction, subaortic stenosis is very likely to be already established, due to VSD Results of ASO restriction.2" Left ventricular hypertrophy conse- Results of ASOs at the RCH for the various anatomic quent to subaortic stenosis may preclude a later subsets described above are summarized in Table I. Fontan procedure in some of these patients. Preser- The lowest-risk group consists of babies with TGA vation of an unobstructed left ventricular outlet and and an IVS operated upon within the 1st 3 weeks of regulation of pulmonary blood flow should be pri- life. The risk of a primary ASO for infants in the 3- mary goals in the treatment of this type of univen- to 8-week age range compares favorably to that of a tricular heart. One way to achieve these goals is to 2-stage approach with a PA band followed by a perform a "palliative" ASO, leaving pulmonary blood shunt, although we do not have a large experience flow under control of the restrictive VSD, with an with the latter strategy. This risk also compares fa-

330 Arterial Switch Volume 24, Number 4, 1997 TABLE 1. Results of the Arterial Switch Operation at TABLE 1ll. Arterial Switch Operation Risk Stratified by Royal Children's Hospital for Various Anatomic Groups Coronary Anatomy Within Anatomic Subgroups

Anatomic Type Hospital Mortality 95% CL Risk (95% CL) Anatomy Non-IMCA IMCA P TGA.IVS 2/222 (0.9%) 0- 3% TGA.VSD 5/121 (4.1%) 1 - 9% (VS 1% (0-3%) 0/14 (0-23%) 1 VSDand 4.8% (2-10%) 0/6 (0-46%) 1 Taussig Bing 2/30 (6.6%) 1 - 22% DORV Discordant (corrected) TGA 1/9 (11%) 0 -48% Total 2.6% (1-5%) 0/20 (0-17%) 1 Tricuspid atresia/DILV 3/12 (25%) 5 - 57% As in Table II, we could not demonstrate a risk increment for intramural coronary artery.

DILV = double-inlet left ventricle; IVS = intact ventricular DORV = double-outlet right ventricle; IMCA = intramural septum; TGA = transposition of the great arteries; VSD = coronary artery; IVS = intact ventricular septum; VSD = ventricular septal defect ventricular septal defect

vorably to that of many other open heart procedures, 72 months were also similar (P >0.05). All survivors especially those performed in neonates. However, are in New York Heart Association (NYHA) class I at risk was higher for the more complex TGA sub- a mean follow-up time of 54 ± 36 months, and all sets.7"2'2' An IMCA has not been an independent risk are in sinus rhythm.12 The risk of an ASO for Taussig- factor for operative mortality, whether considered Bing anomaly also compares very favorably to alter- against non-IMCA patients as a group or within the nate surgical strategies used for similar patients. various anatomic subsets (Tables II and III).426 Our experience with the Senning technique plus Long-term follow-up of our TGA patients (more an ASO for discordant TGA is limited. Fourteen pa- than 1,000 patient-years) has shown that most chil- tients have had the operation since July of 1989.22 dren have experienced normal growth and develop- Age and weight medians were 12 months (range 0.5 ment with a good quality of life following an ASO. to 120 months) and 8.2 kg (range 3.2 to 34 kg). All There were no late deaths in patients undergoing an but 1 patient had a left ventricular to right ventricu- ASO for TGA with an IVS or TGA with a VSD. lar pressure ratio greater than 0.7, due to a large VSD The operative risk of an ASO for 27 infants with (with or without a previous PA band), severe conges- Taussig-Bing anomaly was 7% (confidence limits 1% tive heart failure from right ventricular dysfunction to 23%) and was not increased for patients requiring and tricuspid insufficiency, or a PA band for left ven- concurrent aortic arch obstruction repair (P= 1). 2 tricular retraining. At least 10 patients had strong Actuarial survival and freedom from reoperation at contraindications for "classical" repair, including right ventricular hypoplasia (n=2), moderate to severe TABLE 11. Arterial Switch Operation Risk Stratified by right ventricular dysfunction, (n=5), and/or moder- Coronary Anatomy ate to severe tricuspid insufficiency (n=9). There was 1 hospital death, occurring in a neonate (7%, confi- Coronary Type n Risk (95% CL) P dence limits 0% to 34%). Actuarial survival beyond 10 months was 81% (confidence limits 42% to 95%); total follow-up time is 289 1LCx-2R 219 7/219 (3.2%) (1 -6%) 1 currently patient-months. The median grade of tricuspid insufficiency fell from 1L-2RCx 69 1/69 (1.5%) (0-8%) - 3/4 preoperatively to 1/4 postoperatively (P=0.003). Single 33 3/33 (9%) (2-24%) Right ventricular function is normal in 11 of 12 sur- Intramural 20 0/20 (0-17%) 1 vivors, all but 1 of whom are in NYHA class I or II. Seventeen of 400 ASO patients had some form of 1 LR-2Cx 17 0/17 (0-19%) - anatomic LVOTO, due to accessory endocardial Inverted 17 1/17 (5.8%) (0-29%) - cushion/AV valve tissue, fibromuscular subpulmonic Other 7 0/7 (0-41%) obstruction, or anomalous muscle bands. Actuarial survival at 5 and 10 years following an ASO and There was no significant risk increment for intramural LVOTO resection was similar to the main ASO co- coronary artery versus 1 left, circumflex, 2 right, the most hort (97% versus 94%, P >0.05), but there was a common (and technically the most straightforward) variant. higher probability of reoperation (P <0.005). The Cx = circumflex; L = left; R = right preoperative left ventricle-pulmonary artery gradient was not a good predictor of resectability (Fig. 7).26

Texas Heart InstituteJournal Arterial Switch 331 For infants with a univentricular heart, TGA, and ered, concerns have been raised regarding long-term subaortic stenosis, an ASO as palliative treatment has neurodevelopmental outcome.Y637 Children subjec- carried an operative risk that is high but competitive ted to circulatory arrest for an ASO were found to with those of other treatment strategies (e.g., Nor- have developmental index scores that were lower wood operation, PA band with or without VSD en- (at 1 year) than those of children who had low-flow largement, cardiac transplantation).2' Although the cardiopulmonary bypass. Whether or not the use of ASO has been highly effective for permanent relief full-flow cardiopulmonary bypass affords more neu- of subaortic stenosis in our patients, ultimate suit- rological protection remains to be demonstrated and ability for further operations has been limited in is currently under investigation in our unit. some cases by pulmonary artery distortion related to use of the Lecompte maneuver. Of 12 neonates so Conclusion treated, 7 of 8 long-term survivors had a bidirection- al cavopulmonary shunt, and 5 of these progressed The ASO has emerged as the treatment of choice for to a Fontan procedure (more than 400 patient- most TGA variants. The results compare favorably to months of follow-up). The best treatment strategy for what was achieved in the era of atrial-level repairs, this difficult TGA subset remains undecided, al- and the promise of an improved outlook has been though the Damus connection (with a modified fulfilled at 15 years' follow-up. Unresolved issues Blalock-Taussig shunt) is currently our favored ap- center on the long-term fate of the coronary arteries proach, and we reserve the technically more com- and the neoaortic valve as survivors of a neonatal plex ASO for selected patients. ASO reach their adult years. The ASO in biventricular hearts with TGA comes very close to being a complete anatomic and physi- References ologic correction. The majority of patients (more than 95%) after an ASO, at least those with the less 1. Taussig HB, Bing RJ. Complete transposition of the aorta and complex variants, have normal resting left ventricu- a levoposition of the pulmonary artery: clinical, physiologi- lar function. Segmental perfusion abnormalities may cal, and pathological findings. Am Heart J 1949;37:551-9. on scans at 2. Karl TR. Transposition of the great arteries. In: Nichols DG, be seen occasionally technetium-99 rest, Cameron DE, editors. Critical cardiac disease in infants and but they tend to improve with exercise. These de- children. St. Louis: Mosby-Year Book, Inc., 1994:825-40. fects are not predicted by electrocardiography or 3. Gittenberger-de Groot AC, Sauer U, Oppenheimer-Dekker echocardiography. Left ventricular end-systolic wall A, QuaegebeurJ. Coronary arterial anatomy in transposition stress and fiber-shortening velocity have been rela- of the great arteries: a morphologic study. Pediatr Cardiol tively normal, which suggests that contractility is not 1983;4(Suppl 1):15-24. 4. Asou T, Karl TR, Mee RB. Arterial switch: translocation of impaired. These results are significantly better than the intramural coronary artery. Ann Thorac Surg 1994;57: the best published data concerning atrial-level re- 461-5. pairs.271 The presence of an IMCA at operation has 5. KirklinJW, Colvin EV, McConnell ME, Bargeron LM Jr. Com- not been associated with late death or with ischemic plete transposition of the great arteries: treatment in the cur- features on electrocardiography or echocardiogra- rent era. Pediatr Clin North Am 1990;37:171-7. of 6. Davis AM, Wilkinson JL, Karl TR, Mee RB. Transposition of phy.426 Routine angiographic surveillance post- the great arteries with intact ventricular septum. Arterial operative ASO patients has failed to reveal any switch repair in patients 21 days of age or older. J Thorac coronary anastomotic problems (irrespective of co- Cardiovasc Surg 1993;106:111-5. ronary anatomy and translocation technique). 7. Karl TR, Sano S, Brawn W, Mee RB. Repair of hypoplastic or The most frequent indication for reoperation was interrupted aortic arch via sternotomy. J Thorac Cardiovasc supravalvar pulmonary stenosis (8 patients), but this Surg 1992;104:688-95. 8. Jatene AD, Fontes VF, Paulista PP, deSouza LC, Neger F, complication has been nearly eliminated by our cur- Galantier M, et al. Successful anatomic correction of trans- rent pulmonary artery reconstruction techniques. position of the great vessels. A preliminary report. Arq Bras Following an ASO, there have been tendencies for Cardiol 1975;28:461-4. the great vessel (anastomotic) diameter to be smaller 9. Lecompte Y, Zannini L, Hazan E, Jarreau MM, Bex JP, Tu TV, than that of controls and for the neoaortic root to be et al. Anatomic correction of transposition of the great arteries. J Thorac Cardiovasc Surg 1981;82:629-31. neoaortic root larger. Risk factors for enlargement 10. Quaegebeur JM. The arterial switch operation: rationale, re- include neoaortic insufficiency, a previous PA band, sults and perspectives. Thesis: Leiden University, The Neth- and switch conversion following atrial repair. Fewer erlands, 1986. than half of patients have some evidence of aortic 11. Mee RBB. Results of the arterial switch procedure for com- insufficiency, and the degree is usually trivial. We plete transposition with intact ventricular septum. Cardiol in have aortic valve in 3 chil- the Young 1991;1:97-8. performed replacement 12. Comas JV, Mignosa C, Cochrane AD, Wilkinson JL, Karl TR. dren after an ASO. Taussig-Bing anomaly and arterial switch: aortic arch ob- Although ASO results are now excellent in most struction does not influence outcome. Eur J Cardiothor Surg large centers when operative mortality is consid- 1996;10:1114-9.

332 Arterial Switch Volume 24, Number 4, 1997 13. Kirklin JW, Blackstone EH, Tchervenkov CI, Castanieda AR results after arterial repair for transposition of the great ar- and The Congenital Heart Surgeon's Society. Clinical out- teries. J Thorac Cardiovasc Surg 1992;103:421-7. comes after the arterial switch operation for transposition, 32. Minet P, Vaksmann G, Rey C, Francart C, Breviere GM, patient support, procedural, and institutional risk factors. Dupuis C. Doppler echocardiography after anatomical repair Circulation 1992;86:1501-15. of transposition of the great vessels. Arch Mal Coeur Vaiss 14. Yacoub MH, Radley-Smith R, Maclaurin R. Two-stage opera- 1992;85:515-20. tion for anatomical correction of transposition of the great 33. Serraf A, Lacour-Gayet F, Bruniaux J, Losay J, Petit J, Tou- arteries with intact interventricular septum. Lancet 1977;1: chot-Kone A, et al. Anatomic repair of Taussig-Bing hearts. 1275-8. Circulation 1991;84:II1200-5. 15. KirklinJW, Barratt-Boyes BG. Complete transposition of the 34. Kramer HH, Rammos S, Krian A, Krogmann 0, Ostermeyer great arteries. In: Kirklin JW, Barratt-Boyes BG. Cardiac sur- J, Korbmacher B, et al. Intermediate-term clinical and hemo- gery. New York: Churchill-Livingstone, 1993:1383-1467. dynamic results of the neonatal arterial switch operation for 16. Meisner H, Paek S, Heimisch W, Kunkel R, Lorenz HP, complete transposition of the great arteries. Int J Cardiol Sebening F. Experience with anatomical correction of trans- 1992;36:13-22. position of the great arteries (TGA). Thorac Cardiovasc Surg 35. Vouhe PR, Tamisier D, Leca F, Ouaknine R, Vernant F, 1991;39(Suppl 2):155-9. Neveux JY. Transposition of the great arteries, ventricular 17. Cochrane AD, Karl TR, Mee RB. Staged conversion to arte- septal defect, and pulmonary outflow tract obstruction: rial switch for late failure of the systemic right ventricle. Ann Rastelli or Lecompte procedure? J Thorac Cardiovasc Surg Thorac Surg 1993;56:854-61. 1992;103:428-36. 18. Karl TR, Yemets I, Brizard C, Cochrane A. Arterial switch for 36. Bellinger DC, Jonas RA, Rappaport LA, Wypij D, Wernovsky transposition with left ventricular outflow tract obstruction. G, Kuban KC, et al. Developmental and neurologic status of Proceedings of Second World Congress of Pediatric Cardiol- children after heart surgery with hypothermic circulatory ogy and Cardiac Surgery, 1997. In press. arrest or low-flow cardiopulmonary bypass. New EnglJ Med 19. Milanesi 0, Thiene G, Bini RM, Pellegrino PA. Complete 1995;332:549-55. transposition of great arteries with coarctation of aorta. Br 37. NewburgerJW, Jonas RA, Wernovsky G, Wypij D, Hickey PR, Heart J 1982;48:566-71. Kuban KC, et al. A comparison of the perioperative neuro- 20. Schneeweiss A, Motro M, Shem-Tov A, Neufeld HN. Sub- logic effects of hypothermic circulatory arrest versus low- aortic stenosis: an unrecognized problem in transposition of flow cardiopulmonary bypass in infant heart surgery. New the great arteries. Am J Cardiol 1981;48:336-9. Engl J Med 1993;329:1057-64. 21. Karl TR, Watterson KG, Sano S, Mee RB. Operations for subaortic stenosis in univentricular hearts. Ann Thorac Surg 1991;52:420-7. 22. Karl TR, Weintraub RG, Brizard CP, Cochrane AD, Mee RB. Senning plus arterial switch operation for discordant (congenitally corrected) transposition. Ann Thorac Surg 1997;64: 495-502. 23. Senning A. Surgical correction of transposition of the great vessels. Surgery 1959;45:966-80. 24. Ilbawi MN, DeLeon SY, Backer CL, Duffy CE, Muster AJ, Zales VR, et al. An alternative approach to the surgical management of physiologically corrected transposition with ventricular septal defect and pulmonary stenosis or atresia. J Thorac Cardiovasc Surg 1990;100:410-5. 25. Sano T, Riesenfeld T, Karl TR, Wilkinson JL. Intermediate- term outcome after intracardiac repair of associated cardiac defects in patients with atrioventricular and ventriculoarterial discordance. Circulation 1995;92(9 Suppl):II272-8. 26. Soto R, Brizard CP, Cochrane AD, Karl TR. Intramural coro- naries in transposition of the great arteries, results of arterial switch operation. Proceedings of Second World Congress of Pediatric Cardiology and Cardiac Surgery, 1997. In press. 27. Jatene AD, Fontes VF, Paulista PP, Souza LC, Neger F, Galantier M, et al. Anatomic correction of transposition of the great vessels. J Thorac Cardiovasc Surg 1976;72:364-70. 28. Brawn WJ, Mee RB. Early results for anatomic correction of transposition of the great arteries and for double-outlet right ventricle with subpulmonary ventricular septal defect. J Thorac Cardiovasc Surg 1988;95:230-8. 29. Moat NE, Pawade A, Lamb RK. Complex coronary arterial anatomy in transposition of the great arteries. Arterial switch procedure without coronary relocation. J Thorac Cardiovasc Surg 1992;103:872-6. 30. Veelken N, Gravinghoff L, Keck EW, Freitag HJ. Improved neurological outcome following early anatomical correction of transposition of the great arteries. Clin Cardiol 1992;15: 275-9. 31. Lupinetti FM, Bove EL, Minich LL, Snider AR, Callow LB, MelionesJN, et al. Intermediate-term survival and functional

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