- Email: [email protected]
Staged palliation of single ventricle with Levo-transposition of the great arteries
Progress in Pediatric Cardiology 10 Ž1999. 51]58
Staged palliation of single ventricle with Levo-transposition of the great arteries Ralph S. Mosca1 Pediatric Cardio¨ ascular Surgery, Michigan Congenital Heart Center, Uni¨ ersity of Michigan Medical Center, F7830 Mott Children’s Hospital, 1500 East Medical Center Dri¨ e, Ann Arbor, MI 48109-0223, USA
Abstract Patients born with single ventricle and L-transposition of the great arteries present challenging medical and surgical management problems. This defect is characterized by a wide variation in cardiac morphology and physiology. The clinical spectrum can range from cyanosis due to pulmonary outflow obstruction and venoarterial shunting to congestive heart failure from pulmonary over-circulation and systemic outflow tract obstruction. To avoid major operations in ill neonates and infants, earlier surgical treatment strategies concentrated on less invasive procedures that did not require cardiopulmonary bypass. Because of relatively poor initial results and a small number of patients presenting later as good candidates for the Fontan procedure, more elaborate initial palliative operations have been used. Despite their increasing complexity, these procedures more completely address the underlying anatomic and physiologic problems and have accounted for steadily improved patient survival. Q 1999 Elsevier Science Ireland Ltd. All rights reserved. Keywords: L-Transposition of the great arteries; Single ventricle; Ventricular inversion; Fontan procedure; Surgical palliation
1. Anatomy and terminology When combined with transposition of the great arteries, ventricular inversion Žatrioventricular discordance. is often referred to as L-transposition or corrected transposition of the great arteries w1,2x. Ventricular inversion with two well-formed ventricles is a relatively rare defect, accounting for approximately 0.5% of clinically evident cases of congenital heart disease w3x. Ventricular hypoplasia is often found in hearts with discordant atrioventricular ŽAV. and ventriculoarterial ŽVA. connections w4x. As many as 75% of all cases of single ventricle or univentricular heart are morphologic variants of ventricular inversion w5,6x. Hearts with univentricular AV connections are often classified according to ventricular morphology as
1 Tel.: q1-734-936-4978; fax: q1-734-736-7353 E-mail address: [email protected] ŽR.S. Mosca.
dominant left ventricle, dominant right ventricle or indeterminate ventricle. Right hand ŽD-loop. or left hand ŽL-loop. ventricular architecture can occur when the dominant ventricle is either of left or right ventricular morphology. The most common variant, a dominant ventricle of left ventricular morphology Žsmooth apical trabecular portion., is often referred to as double inlet left ventricle ŽDILV. and represents 78% of cases of single ventricle reported by Van Praagh et al. w7x. The non-dominant ventricle Žchamber. of right ventricular morphology is usually located anteriorly and it almost always supports one or both great arteries. These hearts with DILV may be further subdivided as to the relationship of the great arteries: 1. 2. 3. 4.
Normally related great arteries Right anterior aorta Left anterior aorta Left posterior aorta Žinverted.
1058-9813r99r$ - see front matter Q 1999 Elsevier Science Ireland Ltd. All rights reserved. PII: S 1 0 5 8 - 9 8 1 3 Ž 9 9 . 0 0 0 1 5 - 6
52
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
Architectural abnormalities of the AV valves are frequent and include stenosis and hypoplasia, atresia, and straddling or overriding. Pulmonary outflow tract obstruction is also common in DILV and may be a consequence of posterior deviation of the infundibular septum, anomalous attachments of the right AV valve, redundant AV valve tissue protruding into the outflow tract, pulmonary annular hypoplasia or pulmonary valvar stenosis. Subaortic obstruction may complicate cases of DILV with VA discordance. Usually it is a result of obstruction at the level of the bulboventricular foramen ŽBVF., but it can also be caused by muscular hypertrophy or redundant AV valve tissue within the outlet chamber. Cardiac conduction abnormalities, similar to those described with AV and VA discordance Žcongenitally corrected transposition of the great arteries . and two wellformed ventricles, may also occur. Double inlet right ventricle and double inlet ventricle of indeterminate morphology are rare, accounting for - 10% of the single ventricles studied by Van Praagh et al. w7x. They are excluded from this discussion because of their relative rarity. 1.1. Morphologic subtypes of double inlet left ¨ entricle 1.1.1. Double inlet left ¨ entricle with normally related great arteries This variant, often referred to as the ‘Holmes heart’, was identified in 15% of cases of single ventricle reviewed by Van Praagh et al. ŽType A-I.. The hypoplastic morphologic right ventricular outflow chamber is located anteriorly. Pulmonary blood flow is supplied by communication through the BVF with the dominant left ventricle. If the BVF is restrictive, subpulmonary obstruction often results in reduced pulmonary blood flow and cyanosis. 1.1.2. Double inlet left ¨ entricle with right-sided hypoplastic right ¨ entricle and D-malposition of the great arteries This subtype was observed in 25% of cases of single ventricle reviewed by Van Praagh et al. ŽType A-II.. A hypoplastic right ventricle is located in the subaortic position and, depending on the size of the BVF and the state of the right ventricular outflow tract, it is associated with either subaortic or subpulmonary stenosis. 1.1.3. Double inlet left ¨ entricle with left-sided hypoplastic right ¨ entricle and L-malposition of the great arteries This morphologic arrangement of DILV was reported in 38% of the series reviewed by Van Praagh ŽType A-III. and is predominant in most other pathologic reviews of single ventricle w8,9x. Usually situs solitus of the atria is present. The pulmonary venous
Fig. 1. Single left ventricle with ventriculoarterial discordance. The aorta is positioned anterior to the pulmonary artery. Antegrade systemic blood flow to the hypoplastic ascending aorta Žarrow. occurs through a potentially restrictive muscular bulboventricular foramen. ŽFrom Mosca et al. Ann Thorac Surg 1997;64:1127 used with permission. w36x.
and systemic venous return pass through the rightsided ‘mitral valve’, and a left-sided ‘tricuspid valve’ into the dominant left ventricle. This left-sided AV valve is often straddles or overrides the ventricular septum. The left ventricle communicates through a BVF with the anterior and leftward located right ventricle ŽFig. 1.. The right ventricular chamber may be slit-like or nearly normal depending on the size of the BVF and the degree of straddling of the left AV valve into the right ventricle. Those hearts in which systemic cardiac output is dependent on a BVF and a subaortic outflow chamber often have unrestricted pulmonary blood flow associated with subaortic stenosis, aortic arch hypoplasia or coarctation.
2. Physiology and clinical presentation In patients with univentricular connections such as DILV the clinical features are determined primarily by the presence and degree of pulmonary and systemic outflow tract obstruction and by the integrity of the AV valves. 2.1. Restricti¨ e pulmonary blood flow If moderate pulmonary outflow obstruction or atresia is present, patients may present with hypoxemia and cyanosis in the neonatal period which can progress to profound cyanosis and metabolic acidosis when the
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
ductus arteriosus closes in the first few days of life. For patients with this combination of defects the outlook is greatly improved by the use of prostaglandin E1 which restores adequate pulmonary blood flow, corrects metabolic acidosis and facilitates survival until operation. Occasionally an optimal balance of pulmonary and systemic blood flow is produced by obstruction to pulmonary blood flow from subpulmonary muscular hypertrophy, pulmonary valvar stenosis, redundant fibrous AV valve tissue, or a restrictive subpulmonary BVF ŽType A1.. Although surgical palliation may not be necessary in the newborn period, these patients require close observation because of progressive obstruction to pulmonary blood flow. The volume of pulmonary blood flow predominantly determines the degree of cyanosis, but in those patients with a single ventricle and an intact atrial septum streaming of blood within the ventricles may also be significant. For example ‘favorable streaming’ may occur when the aortic valve is located to the left in patients with atrial situs solitus. Under these circumstances the systemic venous blood is preferentially distributed into the pulmonary artery and pulmonary venous blood is directed into the aorta. Conversely, patients with a right-sided subaortic right ventricle may have ‘unfavorable streaming’ as seen with abnormal blood flow patterns in isolated Dtransposition of the great arteries w10x.
53
Fig. 2. Actuarial survival curves for 191 patients with double-inlet ventricle. The upper dashed curve refers to the survival of patients before definitive surgery. The ¨ ertical bars are the actuarial 70% confidence limits. The numbers refer to the remaining patients still being followed at the time scale noted on the x-axis Žfrom Franklin et al. JTCVS 1991:101Ž5.:770 used with permission. w11x.
blood flow had more guarded prognoses of 36% survival at 1 year and 11% at 10 years ŽFig. 4.. Several other factors also correlated strongly with poor survival rates such as early age at presentation, right atrial isomerism, common AV orifice, pulmonary atresia and extracardiac anomalous pulmonary venous connection.
4. Surgical palliation
2.2. Atrio¨ entricular ¨ al¨ ar regurgitation Significant AV valve regurgitation, producing an additional volume load on the already overworked single ventricle, may cause congestive heart failure in the short term and reduced ventricular function over time, increasing the risk for a future Fontan procedure.
The primary goals of surgical treatment of neonates and infants with DILV are to provide for a reliable
3. Natural history Franklin et al. published one of the most comprehensive analyses of survival in infants with DILV without surgical repair w11x. For the entire cohort of 191 patients the survival rate was 57% at 1 year, 43% at 5 years and 42% at 10 years ŽFig. 2.. The prognosis of individual patients within this group depended significantly on the specific morphologic subtypes. Patients with spontaneously occurring pulmonary outflow tract stenosis and restricted pulmonary blood flow had favorable predicted survival rates of 96% at 1 year and 79% at 10 years ŽFig. 3.. Patients with unobstructed pulmonary blood flow had lower predicted survival rates of 79% at 1 year and 60% at 10 years. Those patients with unobstructed pulmonary blood flow associated with obstruction to systemic
Fig. 3. Curves for survival before definitive surgery for patients with: ŽA. double-inlet left ventricle, discordant VA connection and pulmonary valvar or subvalvar stenosis with balanced pulmonary blood flow; ŽB. the same as in A but with low pulmonary blood flow; ŽC. double-inlet left ventricle and pulmonary atresia with low pulmonary blood flow; ŽD. right atrial isomerism, double-inlet and double outlet right ventricle, a common AV orifice and anomalous pulmonary venous connection with low pulmonary blood flow. Numbers in parentheses represent relative risks with respect to baseline patient Žfrom Franklin et al. JTCVS 1991:101Ž5.:772 used with permission. w11x.
54
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
4.3. Pulmonary artery banding
Fig. 4. Curves for survival before definitive surgery for patients with: ŽE. double-inlet left ventricle and discordant VA connection with high pulmonary blood flow; ŽF. same as in E but with a common AV orifice; ŽG. same as in E but with systemic arterial obstruction with high pulmonary blood flow. Numbers in parentheses are the calculated relative risks with respect to the baseline patient Žfrom Franklin et al. JTCVS 1991:101Ž5.:773 used with permission. w11x.
and controlled pulmonary blood flow andror to relieve systemic outflow tract obstruction.
Reduction in pulmonary artery blood flow by banding of the pulmonary artery may be quite effective and can be performed with conventional extraluminal or endoluminal approaches. Although appropriate banding may be difficult in small cyanotic infants, some authors have reported good results w15]17x. In their review of palliative procedures for patients with DILV, Franklin et al. found a survival rate of 77% at 1 year and 45% at 5 years in patients initially treated by pulmonary artery banding w12x. Well-recognized risks of banding include distortion of the branch pulmonary arteries and the pulmonary valve. Furthermore, pulmonary banding may accelerate existing or potential subaortic stenosis by promoting myocardial hypertrophy w18x. For these reasons, although valuable in selected patients, most authors would advise against pulmonary artery banding in instances of DILV associated with significant subaortic stenosis or aortic arch hypoplasia w19]21x. 4.4. Systemic outflow tract obstruction
4.1. Inadequate pulmonary blood flow Most neonates with DILV and cyanosis on the basis of reduced pulmonary blood flow, should undergo a modified Blalock]Taussig ŽBT. shunt. Division of the main pulmonary artery may often be necessary to avoid excessive pulmonary blood flow. Franklin et al. found that 84% of patients undergoing a systemic to pulmonary artery shunt survived 1 year and 62% survived to 5 years of age w12x. Although the problems of pulmonary artery distortion, perturbation of pulmonary conductance and compliance, and difficulties in effectively controlling pulmonary blood flow persist, advances in surgical technique and perioperative care have resulted in improved survival Ž90]95% at 1 year. in neonates undergoing systemic to pulmonary artery shunts w13,14x. 4.2. Excessi¨ e pulmonary blood flow Without surgical intervention, pulmonary vascular obstructive disease may develop early in infants with unrestricted pulmonary blood flow. In addition, pulmonary over-circulation produces a ventricular volume overload which may result in ventricular dilation and dysfunction. Options for controlling pulmonary blood flow include pulmonary artery banding or transection of the pulmonary artery with creation of a systemic to pulmonary artery shunt.
In patients in whom systemic output is dependent on a BVF, aortic arch hypoplasia, coarctation and subaortic stenosis are relatively common w7x. Effective relief of systemic ventricular outflow tract obstruction is mandatory to optimize palliation in infancy and avoid the conditions that increase the risk of a Fontan procedure Že.g. ventricular hypertrophy.. Numerous surgical procedures have been used to accomplish this: 1. Penkoske et al. reported success in three patients treated by direct enlargement of the BVF and placement of a left ventricle to descending aorta conduit w22x. However, heart block, ventricular dysfunction, recurrent or residual obstruction and ventricular aneurysm formation may complicate direct surgical enlargement of the BVF w23x. Complex systemic outflow tract obstruction may occur within the cavity of the subaortic chamber as a result of hypertrophied ventricular muscle in combination with adjacent AV valve tissue, making surgical resection difficult w24,25x. Finally, apical left ventricle to aortic conduits have been used, but they are limited by technical difficulties in their placement in neonates and small infants, conduit failure, and the inevitable need for a technically complex reoperation w26x. 2. An interposition graft between the pulmonary artery and the descending aorta with banding of the proximal pulmonary artery has also been pro-
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
posed w27x. This technique combines the potential problems of pulmonary artery banding with the need for periodic complex reoperations to incrementally enlarge the graft as the patient grows. Another similar technique involves banding of the main pulmonary artery and creation of a more proximal aortopulmonary window. This approach results in increased pressure and volume work of the systemic ventricle and is often associated with inexact control of pulmonary blood flow. 3. A Damus]Kay]Stansel ŽDKS. procedure has been used with variable success w28]31x. When performed in infants as originally described Žend to side aortopulmonary anastomosis. the procedure often leads to distortion of the great arteries and neoaortic insufficiency w32x. In addition, this approach does not address the more distal aortic arch obstruction commonly associated with these lesions. 4. The arterial switch procedure has been used in effect trading subaortic for subpulmonary obstruction w33x. The resultant pulmonary blood flow is often unpredictable and a subsequent systemic to pulmonary artery shunt may be required. 5. Modifications of the Norwood procedure have been reported with promising results in this subset of patients w20,34]36x. This procedure, consisting of atrial septectomy, division of the aorta and main pulmonary artery at the level of the sinotubular ridge with partial side to side reanastomosis, allograft augmentation of the aortic arch, and a modified BT shunt, effectively addresses many of the anatomic and physiologic problems associated with DILV ŽFigs. 5 and 6.. By mobilizing both great vessels extensively and dividing them well above the semilunar valves, the tailored reconstructed neoaortic arch can be easily reanastomosed to the arterial outlets, regardless of their congenital spatial relationships, without the risk of tension or distortion of the semilunar valves w37x. This completely relieves systemic outflow tract obstruction and avoids the risks of AV heart block and ventricular dysfunction. Although occasionally problematic in small neonates Ž- 2.5 kg., a sufficiently large innominate to pulmonary arterial shunt can usually be fashioned to provide adequate systemic arterial oxygen delivery without pulmonary over-circulation.
55
Fig. 5. Single left ventricle with ventriculoarterial discordance. Following an atrial septectomy, both great vessels are divided just beyond the sinotubular ridge. The ductal tissue is completely excised and the aortic arch is reconstructed with an allograft patch Žfrom Mosca et al. Ann Thorac Surg 1997;64:1127 used with permission. w36x.
plantation in not an acceptable solution for most of these infants and children because of the extreme shortage of appropriate donor hearts and the long term risks of infection and rejection after transplantation. The Fontan operation has been used successfully in virtually all forms of single ventricle lesions. Although improvements in perioperative care and surgical technique have allowed us to amend and expand the original operable criteria for the Fontan procedure w38x, a variety of persistent anatomic and physiologic abnormalities are associated with significant continu-
5. Summary Children born with functionally univentricular hearts ultimately require either a Fontan type of operation or cardiac transplantation. Currently trans-
Fig. 6. Single left ventricle with ventriculoarterial discordance. The completed repair is shown Žfrom Mosca et al. Ann Thorac Surg 1997;64:1128 used with permission. w36x.
56
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
ing risks w39]43x. In neonates and infants with single ventricle the goal of palliation is to avoid accruing risk factors and to provide the optimal anatomic and physiologic conditions for performing a Fontan procedure in early childhood. Diastolic ventricular function, although difficult to accurately measure, is thought to be important in determining the efficiency of a single ventricle w18,22,39,44x. In hearts with DILV and a subaortic outlet chamber, adequate systemic blood flow is dependent on an entirely muscular outlet, the BVF. Persistent restriction to systemic blood flow may produce narrowing of the BVF w45,46x, with progressive ventricular hypertrophy, subendocardial ischemia and diminished ventricular compliance. Relief or bypass of this obstruction is mandatory. Because of earlier reports of poor results with DKS types of surgery in infants, some authors have advocated a direct resection of the BVF if it is obstructive w47,48x. More recently the trend in palliation has been to create an aortopulmonary anastomosis and a small systemic to pulmonary artery shunt w34]36,49x. In infants with unrestricted pulmonary blood flow and systemic pulmonary artery pressures, early pulmonary vascular obstructive disease will develop without surgical intervention. The associated pulmonary over-circulation also produces a significant ventricular volume overload associated with ventricular dilation and ultimately with ventricular dysfunction. Patients with DILV associated with a subaortic outflow chamber and no pulmonary stenosis pose difficult management problems because they are at continued risk of both progressive subaortic stenosis and early development of pulmonary vascular obstructive disease. Pulmonary artery banding would seem to afford the simplest solution for controlling pulmonary blood flow in these patients. Although some authors continue to use pulmonary artery banding, others have pointed out potential difficulties and detrimental changes that may ultimately impact unfavorably upon the patient’s candidacy for the Fontan procedure w50,51x. The BVF, bounded entirely by muscle, may be obstructive at birth or become narrowed insidiously over time. Mattitau et al. have shown that although the BVF appear to grow in many patients, in the majority this growth does not keep pace with the child’s somatic growth and thus they eventually become obstructive w51x. Placement of a pulmonary artery band appears to accelerate the diminution in size of the BVF w52x. Moreover, the acute volume changes that occur after the Fontan procedure w53x may further exacerbate the outflow obstruction that with time has been reported to progress w54x. The most effective surgical treatment of aortic arch hypoplasia and obstruction has also been debated. In the series of patients reported by Franklin et al. those
Fig. 7. Actuarial survival curves for patients palliated with a Shunt Žsystemic-pulmonary arterial shunt., Band Žbanding of the pulmonary artery trunk. and Coarct Žrepair of an aortic coarctation or interruption with banding of the pulmonary trunk.. The dashed lines refer to survival of the patients before definitive surgery. The 70% confidence limits are shown and the numbers represent the patients remaining from each group still being followed at the time on the x-axis. Žfrom Franklin et al. JTCVS 1991:101Ž5.:919 used with permission. w12x.
who had pulmonary artery banding and repair of the aortic arch obstruction had the poorest outcomes, 44% survival at 1 year and 22% at 5 years w12x ŽFig. 7.. In fact, the hazard rate for the definitive operation showed a two]four-fold higher risk in patients undergoing associated aortic arch repair. This was likely due to the inability to completely relieve the arch obstruction when performed via a left thoracotomy. In the palliative treatment of infants with single ventricle, the complete relief of aortic arch obstruction is important in determining both short- and long-term prognosis. Often the proximal aortic obstruction requires augmentation from the distal ascending aorta to well beyond the insertion of the ductus arteriosus. This procedure is best approached from a median sternotomy using profound hypothermia and a brief period of circulatory arrest, allowing for an extensive mobilization and augmentation of the ascending, transverse and proximal descending thoracic aorta. We recently reviewed our experience with the modified Norwood procedure for the treatment of single left ventricle and VA discordance w36x. Thirty-eight patients with either tricuspid atresia Ž n s 10. or double inlet left ventricle Ž n s 28. and VA discordance underwent the procedure at a mean age of 15 days and a mean weight of 3.4 kg. Aortic arch anomalies were present in 92% of patients. The actuarial survival rates were 89% at one month after surgery, 81% at 1 year and 79% at 5 years. Follow-up studies were carried out in all of the children at a mean interval of 30 " 9 months. None had significant neoaortic valve insufficiency and only one patient required treatment of residual aortic arch obstruction. Most importantly, all surviving patients were found to be excellent can-
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
didates for the Fontan procedure. Consequently, we join with others in recommending the modified Norwood procedure as the procedure of choice for palliation of infants with this subgroup of single ventricle. The palliative treatment of patients with single left ventricle and L-transposition continues to evolve. Further improvements appear promising as the lessons of earlier surgical strategies are combined with the continued advances in perioperative care of infants with single ventricle lesions associated with shunt-dependent pulmonary blood flow. References w1x Van Praagh R. The segmental approach to diagnosis in congenital heart disease. The fourth conference on the clinical delineation of birth defects Part XV. The cardiovascular system. Birth Defects 1972;8:4]23. w2x Bliddal J. Four cases of congenitally corrected transposition with associated defects. Danish Med Bull 1976;23:184]192. w3x Kidd BL. Congenitally corrected transposition of the great arteries. In: Keith JD, Rowe RD, Vlad P, editors. Heart disease in infancy and childhood. New York: MacMillan, 1978:612]627. w4x Erath HG Jr, Graham Jr. TP, Hammon Jr. JW, Smith CW. Hypoplasia of the systemic ventricle in congenitally corrected transposition of the great arteries; Pre-operative documentation and possible implication of operation. JTCVS 1980; 79:770]775. w5x Anderson RH. Ventricular morphology in the univentricular heart. Herz 1979;4:184. w6x VanPraagh R, Plette JA, VanPraagh S. Single ventricle: Pathology, embryology, terminology, and classification. Herz 1979;4:113]150. w7x VanPraagh R, Ongley PA, Swan HJC. Anatomic types of single or common ventricle in man: Morphologic and geometric aspects of 60 necropsied cases. Am J Cardiol 1964;13:367. w8x Lev M, Liberthson RR, Kirkpatrick JR et al. Single Žprimitive. ventricle. Circulation 1969;39:577. w9x Soto B, Bertranou EG, Bream PR et al. Angiographic study of the univentricular heart of right ventricular type. Circulation 1979;60:1325. w10x Rahimtoula SH, Ongley P, Swan HJC. The hemodynamics of common ventricle. Circulation 1966;34:14. w11x Franklin RCG, Spieglehalter DJ, Anderson RH et al. Double inlet ventricle presenting in infancy. I. Survival without definitive repair. JTCVS 1991;101Ž5.:676]777. w12x Franklin RCG, Spieglehalter DJ, Anderson RH et al. Double inlet ventricle presenting in infancy. II Results of palliative operations. JTCVS 1991;101Ž5.:917]923. w13x Odim J, Portzky M, Zurakowski D et al. Sternotomy approach for the modified Blalock-Taussig shunt. Circulation 1995;92Ž9 Suppl.:II256]II261. w14x Fermanis GG, Ekangaki AK, Solmon AP et al. Twelve year experience with the modified Blalock]Taussig Shunt in neonates. Eur J Cardio-Thorac Surg 1992;6Ž11.:586]589. w15x Webber SA, LeBlanc JG, Keeton BR et al. Pulmonary artery banding is not contraindicated in double inlet left ventricle with transposition and aortic arch obstruction. Eur J CardioThorac Surg 1995;9:515]520. w16x Jensen RA, Williams RG, Laks H et al. Usefulness of banding of the pulmonary trunk with single ventricle physiology at risk of subaortic obstruction. Am J Cardiol 1996;77: 1089]1093.
57
w17x Koh Y, Imai Y, Kurosaua H et al. wPulmonary artery banding for double inlet left ventriclex. Nippon Kyobyu Geka Gakkai Zasshi 1990;38Ž2.:194]200. w18x Freedom RM, Benson LN, Smallhorn JF et al. Subaortic stenosis, the univentricular heart, and banding of the pulmonary artery: An analysis of the course of 43 patients with univentricular heart palliated by pulmonary artery banding. Circulation 1986;73:758]764. w19x Franklin RCG, Sulligan ID, Anderson RH. Is banding of the pulmonary trunk obsolete for infants with tricuspid atresia and double inlet ventricle with a discordant ventriculoarterial connection? Role of aortic arch obstruction and subaortic stenosis. J Am Coll Cardiol 1990;16:1455]1464. w20x Jonas RA, Castaneda AR, Lang P. Single ventricle Žsingle or double-inlet. complicated by subaortic stenosis. Surgical options in infancy. Ann Thorac Surg 1985;39Ž4.:361]365. w21x Ilbawi MN, DeLeon SY, Wilson WR et al. Advantages of early relief of subaortic stenosis in single ventricle equivalents. Ann Thorac Surg 1991;52:842]849. w22x Penkoske PA, Freedom RM, Williams WG et al. Surgical palliation of subaortic stenosis in the univentricular heart. J Thorac Cardiovasc Surg 1984;87:767]781. w23x O’Leary PU, Driscoll DJ, Connor AR et al. Subaortic obstruction in hearts with a univentricular connection to a dominant left ventricle and an anterior subaortic outlet chamber: Results of a staged approach. J Thorac Cardiovasc Surg 1990;106:1231]1238. w24x Cheung HC, Lincoln C, Anderson RH et al. Options for surgical repair in hearts with univentricular atrioventricular connection and subaortic stenosis. J Thorac Cardiovasc Surg 1990;160:672]681. w25x Freedom RM, Dische MR, Rowe RD. Pathologic anatomy of subaortic stenosis and atresia in the first year of life. Am J Cardiol 1977;39:1035]1043. w26x Frommelt DC, Rocchini AP, Bove EL. Natural history of apical left ventricle to aortic conduit in pediatric patients. Circulation 1991;89Žsuppl 3.:217]218. w27x Litwin SB, Van Praagh R, Bernhard WF. A palliative operation for certain infants with aortic arch interruption. Ann Thorac Surg 1972;14:369. w28x Damus PS. Letter to the editor. Ann Thorac Surg 1975; 20:724]725. w29x Kay MP. Anatomic correction for transposition of the great arteries. Mayo Clin Proc 1975;50:638]640. w30x Stansel HC. A new operation for d-loop transposition of the great arteries. Ann Thorac Surg 1975;19:565]567. w31x Lin AE, Laks H, Barber G et al. Subaortic obstruction in complex congenital heart disease, management by proximal pulmonary artery to ascending aorta and to side anastomosis. J Am Coll Cardiol 1986;7:617]624. w32x Lui RC, Williams WG, Trusler GA et al. Experience with the Damus ] Kaye ] Stansel procedure for children with Taussig]Bing hearts or univentricular hearts with subaortic stenosis. Circulation 1993;88Žpt 2.:170]176. w33x Lacour-Gayet F, Serraf A, Formont L et al. Early palliation of univentricular hearts with subaortic stenosis and ventriculoarterial discordance. J Thorac Cardiovasc Surg 1992; 109:1238]1245. w34x Jacobs ML, Rychik J, Donfrio MT. Avoidance of subaortic obstruction in staged management of single ventricle’. Ann Thorac Surg 1995;60Ž6 Suppl.:S543]S545. w35x Van Son JAM, Reddy VM, Haas GS et al. Modified surgical techniques for relief of aortic obstruction in ŽS,L,L. hearts with rudimentary right ventricles and restrictive bulboventricular foramen. J Thorac Cardiovasc Surg 1996;110:909]915. w36x Mosca RS, Hennein HA, Kulik TJ et al. Modified Norwood operation for single left ventricle and ventriculoarterial dis-
58
w37x w38x
w39x w40x
w41x
w42x
w43x w44x
w45x
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58 cordance: An improved surgical technique. Ann Thorac Surg 1997;64:1126]1132. Waldmon JD, Lamberti JJ, George L et al. Experience with the Damus procedure. Circulation 1988;78ŽPt 2.:III32]III39. Choussat A, Fontan F, Besse P. Selection criteria for Fontan’s procedure. In: Anderson RH, Shinebourine EA, editors. Paediatric cardiology. Edinburgh: Churchill and Livingstone, 1978:559]566. Kirklin JK, Blackstone EH, Kirklin JW et al. The Fontan operation: Ventricula hypertrophy, age, and date of operation as risk factors. J Thorac Cardiovasc Surg 1986;92:1049. Cetta F, Feldt RH, O’Leary PW et al. Improved early morbidity and mortality after Fontan operation: The Mayo Clinic experience. 1987]1992.. J Am Coll Cardiol 1996;28Ž2.: 480]486. Knott-Craig CJ, Danielson GK, Schaff HV et al. The modified Fontan operation. An analysis of risk factors for early postoperative death or takedown in 702 consecutive patients from one institution. J Thorac Cardiovasc Surg 1995;109Ž6.: 1237]1243. Kalitz R, Zimer G, Luhmer I et al. Modified Fontan operation in functionally univentricular hearts: Preoperative risk factors and intermediate results. J Thorac Cardiovasc Surg 1996;112Ž3.:658]664. Gentles TL, Mayer JE Jr, Gauvreau K et al. Fontan operation in 500 consecutive patients: Factors influencing early and late outcome. J Thorac Cardiovasc Surg 1997;114Ž3.:376]391. Fontan F, Fernandez G, Ebner A. Double inlet univentricular heart: Experience with Fontan procedure. In: Baue AE et al., editor. Glenn’s thoracic and cardiovascular surgery. Norwalk, CT: Appleton and Lange, 1991:1061]1068. Mesko ZG, Jones JE, Nadas AS. Diminution and closure of large ventricular septal defects after pulmonary artery banding. Circulation 1973;48:847]855.
w46x Freedon RM. The dinosaur and banding of the main pulmonary trunk in the in the heart with functionally one ventricle and transposition of the great arteries: A saga of abolition and caution. J Am Coll Cardiol 1987;10:427]429. w47x McKay R, Pacifico AD, Blackstone EH et al. Septation of the univentricular heart with left anterior subaortic outlet chamber. J Thorac Cardiovasc Surg 1982;84:77]87. w48x Carter TL, Mainwaring RD, Lamberti JJ. Damus]Kaye] Stansel procedure: Mid-term follow-up and technical consideration. Ann Thorac Surg 1994;58:1603]1608. w49x Rothmon A, Long P, Lock JE et al. Surgical management of subaortic obstruction in single left ventricle and tricuspid atresia. J Am Coll Cardiol 1987;10Ž2.:421]426. w50x Juaneda E, Haworth SG. Pulmonary vascular structure in patients dying after the Fontan procedure: The lung as a risk factor. Br Heart J 1984;52:575]580. w51x Matitiau A, Geva T, Colan SD et al. Bulboventricular foramen size in infants with double-inlet left ventricle or tricuspid atresia with transposed great arteries: Influence on initial palliative operation and rate of growth. J Am Coll Cardiol 1992;19:142]148. w52x Freedom RM, Sondheiman H, Dische R, Rowe RD. Development of ‘subaortic stenosis’ after pulmonary artery banding for common ventricle. Am J Cardiol 1977;39:78]83. w53x Donofrio MT, Jacobs ML, Norwood WI, Rychik J. Early changes in ventricular septal defect size and ventricular geometry in the single left ventricle after volume-unloading surgery. J Am Coll Cardiol 1995;26:1008]1015. w54x Finta KM, Beekman RH, Lupinetti FM, Bove EL. Ventricular outflow obstruction progresses after the Fontan operation. Ann Thorac Surg 1994;58Ž4.:1108]1113.
Staged palliation of single ventricle with Levo-transposition of the great arteries Ralph S. Mosca1 Pediatric Cardio¨ ascular Surgery, Michigan Congenital Heart Center, Uni¨ ersity of Michigan Medical Center, F7830 Mott Children’s Hospital, 1500 East Medical Center Dri¨ e, Ann Arbor, MI 48109-0223, USA
Abstract Patients born with single ventricle and L-transposition of the great arteries present challenging medical and surgical management problems. This defect is characterized by a wide variation in cardiac morphology and physiology. The clinical spectrum can range from cyanosis due to pulmonary outflow obstruction and venoarterial shunting to congestive heart failure from pulmonary over-circulation and systemic outflow tract obstruction. To avoid major operations in ill neonates and infants, earlier surgical treatment strategies concentrated on less invasive procedures that did not require cardiopulmonary bypass. Because of relatively poor initial results and a small number of patients presenting later as good candidates for the Fontan procedure, more elaborate initial palliative operations have been used. Despite their increasing complexity, these procedures more completely address the underlying anatomic and physiologic problems and have accounted for steadily improved patient survival. Q 1999 Elsevier Science Ireland Ltd. All rights reserved. Keywords: L-Transposition of the great arteries; Single ventricle; Ventricular inversion; Fontan procedure; Surgical palliation
1. Anatomy and terminology When combined with transposition of the great arteries, ventricular inversion Žatrioventricular discordance. is often referred to as L-transposition or corrected transposition of the great arteries w1,2x. Ventricular inversion with two well-formed ventricles is a relatively rare defect, accounting for approximately 0.5% of clinically evident cases of congenital heart disease w3x. Ventricular hypoplasia is often found in hearts with discordant atrioventricular ŽAV. and ventriculoarterial ŽVA. connections w4x. As many as 75% of all cases of single ventricle or univentricular heart are morphologic variants of ventricular inversion w5,6x. Hearts with univentricular AV connections are often classified according to ventricular morphology as
1 Tel.: q1-734-936-4978; fax: q1-734-736-7353 E-mail address: [email protected] ŽR.S. Mosca.
dominant left ventricle, dominant right ventricle or indeterminate ventricle. Right hand ŽD-loop. or left hand ŽL-loop. ventricular architecture can occur when the dominant ventricle is either of left or right ventricular morphology. The most common variant, a dominant ventricle of left ventricular morphology Žsmooth apical trabecular portion., is often referred to as double inlet left ventricle ŽDILV. and represents 78% of cases of single ventricle reported by Van Praagh et al. w7x. The non-dominant ventricle Žchamber. of right ventricular morphology is usually located anteriorly and it almost always supports one or both great arteries. These hearts with DILV may be further subdivided as to the relationship of the great arteries: 1. 2. 3. 4.
Normally related great arteries Right anterior aorta Left anterior aorta Left posterior aorta Žinverted.
1058-9813r99r$ - see front matter Q 1999 Elsevier Science Ireland Ltd. All rights reserved. PII: S 1 0 5 8 - 9 8 1 3 Ž 9 9 . 0 0 0 1 5 - 6
52
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
Architectural abnormalities of the AV valves are frequent and include stenosis and hypoplasia, atresia, and straddling or overriding. Pulmonary outflow tract obstruction is also common in DILV and may be a consequence of posterior deviation of the infundibular septum, anomalous attachments of the right AV valve, redundant AV valve tissue protruding into the outflow tract, pulmonary annular hypoplasia or pulmonary valvar stenosis. Subaortic obstruction may complicate cases of DILV with VA discordance. Usually it is a result of obstruction at the level of the bulboventricular foramen ŽBVF., but it can also be caused by muscular hypertrophy or redundant AV valve tissue within the outlet chamber. Cardiac conduction abnormalities, similar to those described with AV and VA discordance Žcongenitally corrected transposition of the great arteries . and two wellformed ventricles, may also occur. Double inlet right ventricle and double inlet ventricle of indeterminate morphology are rare, accounting for - 10% of the single ventricles studied by Van Praagh et al. w7x. They are excluded from this discussion because of their relative rarity. 1.1. Morphologic subtypes of double inlet left ¨ entricle 1.1.1. Double inlet left ¨ entricle with normally related great arteries This variant, often referred to as the ‘Holmes heart’, was identified in 15% of cases of single ventricle reviewed by Van Praagh et al. ŽType A-I.. The hypoplastic morphologic right ventricular outflow chamber is located anteriorly. Pulmonary blood flow is supplied by communication through the BVF with the dominant left ventricle. If the BVF is restrictive, subpulmonary obstruction often results in reduced pulmonary blood flow and cyanosis. 1.1.2. Double inlet left ¨ entricle with right-sided hypoplastic right ¨ entricle and D-malposition of the great arteries This subtype was observed in 25% of cases of single ventricle reviewed by Van Praagh et al. ŽType A-II.. A hypoplastic right ventricle is located in the subaortic position and, depending on the size of the BVF and the state of the right ventricular outflow tract, it is associated with either subaortic or subpulmonary stenosis. 1.1.3. Double inlet left ¨ entricle with left-sided hypoplastic right ¨ entricle and L-malposition of the great arteries This morphologic arrangement of DILV was reported in 38% of the series reviewed by Van Praagh ŽType A-III. and is predominant in most other pathologic reviews of single ventricle w8,9x. Usually situs solitus of the atria is present. The pulmonary venous
Fig. 1. Single left ventricle with ventriculoarterial discordance. The aorta is positioned anterior to the pulmonary artery. Antegrade systemic blood flow to the hypoplastic ascending aorta Žarrow. occurs through a potentially restrictive muscular bulboventricular foramen. ŽFrom Mosca et al. Ann Thorac Surg 1997;64:1127 used with permission. w36x.
and systemic venous return pass through the rightsided ‘mitral valve’, and a left-sided ‘tricuspid valve’ into the dominant left ventricle. This left-sided AV valve is often straddles or overrides the ventricular septum. The left ventricle communicates through a BVF with the anterior and leftward located right ventricle ŽFig. 1.. The right ventricular chamber may be slit-like or nearly normal depending on the size of the BVF and the degree of straddling of the left AV valve into the right ventricle. Those hearts in which systemic cardiac output is dependent on a BVF and a subaortic outflow chamber often have unrestricted pulmonary blood flow associated with subaortic stenosis, aortic arch hypoplasia or coarctation.
2. Physiology and clinical presentation In patients with univentricular connections such as DILV the clinical features are determined primarily by the presence and degree of pulmonary and systemic outflow tract obstruction and by the integrity of the AV valves. 2.1. Restricti¨ e pulmonary blood flow If moderate pulmonary outflow obstruction or atresia is present, patients may present with hypoxemia and cyanosis in the neonatal period which can progress to profound cyanosis and metabolic acidosis when the
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
ductus arteriosus closes in the first few days of life. For patients with this combination of defects the outlook is greatly improved by the use of prostaglandin E1 which restores adequate pulmonary blood flow, corrects metabolic acidosis and facilitates survival until operation. Occasionally an optimal balance of pulmonary and systemic blood flow is produced by obstruction to pulmonary blood flow from subpulmonary muscular hypertrophy, pulmonary valvar stenosis, redundant fibrous AV valve tissue, or a restrictive subpulmonary BVF ŽType A1.. Although surgical palliation may not be necessary in the newborn period, these patients require close observation because of progressive obstruction to pulmonary blood flow. The volume of pulmonary blood flow predominantly determines the degree of cyanosis, but in those patients with a single ventricle and an intact atrial septum streaming of blood within the ventricles may also be significant. For example ‘favorable streaming’ may occur when the aortic valve is located to the left in patients with atrial situs solitus. Under these circumstances the systemic venous blood is preferentially distributed into the pulmonary artery and pulmonary venous blood is directed into the aorta. Conversely, patients with a right-sided subaortic right ventricle may have ‘unfavorable streaming’ as seen with abnormal blood flow patterns in isolated Dtransposition of the great arteries w10x.
53
Fig. 2. Actuarial survival curves for 191 patients with double-inlet ventricle. The upper dashed curve refers to the survival of patients before definitive surgery. The ¨ ertical bars are the actuarial 70% confidence limits. The numbers refer to the remaining patients still being followed at the time scale noted on the x-axis Žfrom Franklin et al. JTCVS 1991:101Ž5.:770 used with permission. w11x.
blood flow had more guarded prognoses of 36% survival at 1 year and 11% at 10 years ŽFig. 4.. Several other factors also correlated strongly with poor survival rates such as early age at presentation, right atrial isomerism, common AV orifice, pulmonary atresia and extracardiac anomalous pulmonary venous connection.
4. Surgical palliation
2.2. Atrio¨ entricular ¨ al¨ ar regurgitation Significant AV valve regurgitation, producing an additional volume load on the already overworked single ventricle, may cause congestive heart failure in the short term and reduced ventricular function over time, increasing the risk for a future Fontan procedure.
The primary goals of surgical treatment of neonates and infants with DILV are to provide for a reliable
3. Natural history Franklin et al. published one of the most comprehensive analyses of survival in infants with DILV without surgical repair w11x. For the entire cohort of 191 patients the survival rate was 57% at 1 year, 43% at 5 years and 42% at 10 years ŽFig. 2.. The prognosis of individual patients within this group depended significantly on the specific morphologic subtypes. Patients with spontaneously occurring pulmonary outflow tract stenosis and restricted pulmonary blood flow had favorable predicted survival rates of 96% at 1 year and 79% at 10 years ŽFig. 3.. Patients with unobstructed pulmonary blood flow had lower predicted survival rates of 79% at 1 year and 60% at 10 years. Those patients with unobstructed pulmonary blood flow associated with obstruction to systemic
Fig. 3. Curves for survival before definitive surgery for patients with: ŽA. double-inlet left ventricle, discordant VA connection and pulmonary valvar or subvalvar stenosis with balanced pulmonary blood flow; ŽB. the same as in A but with low pulmonary blood flow; ŽC. double-inlet left ventricle and pulmonary atresia with low pulmonary blood flow; ŽD. right atrial isomerism, double-inlet and double outlet right ventricle, a common AV orifice and anomalous pulmonary venous connection with low pulmonary blood flow. Numbers in parentheses represent relative risks with respect to baseline patient Žfrom Franklin et al. JTCVS 1991:101Ž5.:772 used with permission. w11x.
54
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
4.3. Pulmonary artery banding
Fig. 4. Curves for survival before definitive surgery for patients with: ŽE. double-inlet left ventricle and discordant VA connection with high pulmonary blood flow; ŽF. same as in E but with a common AV orifice; ŽG. same as in E but with systemic arterial obstruction with high pulmonary blood flow. Numbers in parentheses are the calculated relative risks with respect to the baseline patient Žfrom Franklin et al. JTCVS 1991:101Ž5.:773 used with permission. w11x.
and controlled pulmonary blood flow andror to relieve systemic outflow tract obstruction.
Reduction in pulmonary artery blood flow by banding of the pulmonary artery may be quite effective and can be performed with conventional extraluminal or endoluminal approaches. Although appropriate banding may be difficult in small cyanotic infants, some authors have reported good results w15]17x. In their review of palliative procedures for patients with DILV, Franklin et al. found a survival rate of 77% at 1 year and 45% at 5 years in patients initially treated by pulmonary artery banding w12x. Well-recognized risks of banding include distortion of the branch pulmonary arteries and the pulmonary valve. Furthermore, pulmonary banding may accelerate existing or potential subaortic stenosis by promoting myocardial hypertrophy w18x. For these reasons, although valuable in selected patients, most authors would advise against pulmonary artery banding in instances of DILV associated with significant subaortic stenosis or aortic arch hypoplasia w19]21x. 4.4. Systemic outflow tract obstruction
4.1. Inadequate pulmonary blood flow Most neonates with DILV and cyanosis on the basis of reduced pulmonary blood flow, should undergo a modified Blalock]Taussig ŽBT. shunt. Division of the main pulmonary artery may often be necessary to avoid excessive pulmonary blood flow. Franklin et al. found that 84% of patients undergoing a systemic to pulmonary artery shunt survived 1 year and 62% survived to 5 years of age w12x. Although the problems of pulmonary artery distortion, perturbation of pulmonary conductance and compliance, and difficulties in effectively controlling pulmonary blood flow persist, advances in surgical technique and perioperative care have resulted in improved survival Ž90]95% at 1 year. in neonates undergoing systemic to pulmonary artery shunts w13,14x. 4.2. Excessi¨ e pulmonary blood flow Without surgical intervention, pulmonary vascular obstructive disease may develop early in infants with unrestricted pulmonary blood flow. In addition, pulmonary over-circulation produces a ventricular volume overload which may result in ventricular dilation and dysfunction. Options for controlling pulmonary blood flow include pulmonary artery banding or transection of the pulmonary artery with creation of a systemic to pulmonary artery shunt.
In patients in whom systemic output is dependent on a BVF, aortic arch hypoplasia, coarctation and subaortic stenosis are relatively common w7x. Effective relief of systemic ventricular outflow tract obstruction is mandatory to optimize palliation in infancy and avoid the conditions that increase the risk of a Fontan procedure Že.g. ventricular hypertrophy.. Numerous surgical procedures have been used to accomplish this: 1. Penkoske et al. reported success in three patients treated by direct enlargement of the BVF and placement of a left ventricle to descending aorta conduit w22x. However, heart block, ventricular dysfunction, recurrent or residual obstruction and ventricular aneurysm formation may complicate direct surgical enlargement of the BVF w23x. Complex systemic outflow tract obstruction may occur within the cavity of the subaortic chamber as a result of hypertrophied ventricular muscle in combination with adjacent AV valve tissue, making surgical resection difficult w24,25x. Finally, apical left ventricle to aortic conduits have been used, but they are limited by technical difficulties in their placement in neonates and small infants, conduit failure, and the inevitable need for a technically complex reoperation w26x. 2. An interposition graft between the pulmonary artery and the descending aorta with banding of the proximal pulmonary artery has also been pro-
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
posed w27x. This technique combines the potential problems of pulmonary artery banding with the need for periodic complex reoperations to incrementally enlarge the graft as the patient grows. Another similar technique involves banding of the main pulmonary artery and creation of a more proximal aortopulmonary window. This approach results in increased pressure and volume work of the systemic ventricle and is often associated with inexact control of pulmonary blood flow. 3. A Damus]Kay]Stansel ŽDKS. procedure has been used with variable success w28]31x. When performed in infants as originally described Žend to side aortopulmonary anastomosis. the procedure often leads to distortion of the great arteries and neoaortic insufficiency w32x. In addition, this approach does not address the more distal aortic arch obstruction commonly associated with these lesions. 4. The arterial switch procedure has been used in effect trading subaortic for subpulmonary obstruction w33x. The resultant pulmonary blood flow is often unpredictable and a subsequent systemic to pulmonary artery shunt may be required. 5. Modifications of the Norwood procedure have been reported with promising results in this subset of patients w20,34]36x. This procedure, consisting of atrial septectomy, division of the aorta and main pulmonary artery at the level of the sinotubular ridge with partial side to side reanastomosis, allograft augmentation of the aortic arch, and a modified BT shunt, effectively addresses many of the anatomic and physiologic problems associated with DILV ŽFigs. 5 and 6.. By mobilizing both great vessels extensively and dividing them well above the semilunar valves, the tailored reconstructed neoaortic arch can be easily reanastomosed to the arterial outlets, regardless of their congenital spatial relationships, without the risk of tension or distortion of the semilunar valves w37x. This completely relieves systemic outflow tract obstruction and avoids the risks of AV heart block and ventricular dysfunction. Although occasionally problematic in small neonates Ž- 2.5 kg., a sufficiently large innominate to pulmonary arterial shunt can usually be fashioned to provide adequate systemic arterial oxygen delivery without pulmonary over-circulation.
55
Fig. 5. Single left ventricle with ventriculoarterial discordance. Following an atrial septectomy, both great vessels are divided just beyond the sinotubular ridge. The ductal tissue is completely excised and the aortic arch is reconstructed with an allograft patch Žfrom Mosca et al. Ann Thorac Surg 1997;64:1127 used with permission. w36x.
plantation in not an acceptable solution for most of these infants and children because of the extreme shortage of appropriate donor hearts and the long term risks of infection and rejection after transplantation. The Fontan operation has been used successfully in virtually all forms of single ventricle lesions. Although improvements in perioperative care and surgical technique have allowed us to amend and expand the original operable criteria for the Fontan procedure w38x, a variety of persistent anatomic and physiologic abnormalities are associated with significant continu-
5. Summary Children born with functionally univentricular hearts ultimately require either a Fontan type of operation or cardiac transplantation. Currently trans-
Fig. 6. Single left ventricle with ventriculoarterial discordance. The completed repair is shown Žfrom Mosca et al. Ann Thorac Surg 1997;64:1128 used with permission. w36x.
56
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
ing risks w39]43x. In neonates and infants with single ventricle the goal of palliation is to avoid accruing risk factors and to provide the optimal anatomic and physiologic conditions for performing a Fontan procedure in early childhood. Diastolic ventricular function, although difficult to accurately measure, is thought to be important in determining the efficiency of a single ventricle w18,22,39,44x. In hearts with DILV and a subaortic outlet chamber, adequate systemic blood flow is dependent on an entirely muscular outlet, the BVF. Persistent restriction to systemic blood flow may produce narrowing of the BVF w45,46x, with progressive ventricular hypertrophy, subendocardial ischemia and diminished ventricular compliance. Relief or bypass of this obstruction is mandatory. Because of earlier reports of poor results with DKS types of surgery in infants, some authors have advocated a direct resection of the BVF if it is obstructive w47,48x. More recently the trend in palliation has been to create an aortopulmonary anastomosis and a small systemic to pulmonary artery shunt w34]36,49x. In infants with unrestricted pulmonary blood flow and systemic pulmonary artery pressures, early pulmonary vascular obstructive disease will develop without surgical intervention. The associated pulmonary over-circulation also produces a significant ventricular volume overload associated with ventricular dilation and ultimately with ventricular dysfunction. Patients with DILV associated with a subaortic outflow chamber and no pulmonary stenosis pose difficult management problems because they are at continued risk of both progressive subaortic stenosis and early development of pulmonary vascular obstructive disease. Pulmonary artery banding would seem to afford the simplest solution for controlling pulmonary blood flow in these patients. Although some authors continue to use pulmonary artery banding, others have pointed out potential difficulties and detrimental changes that may ultimately impact unfavorably upon the patient’s candidacy for the Fontan procedure w50,51x. The BVF, bounded entirely by muscle, may be obstructive at birth or become narrowed insidiously over time. Mattitau et al. have shown that although the BVF appear to grow in many patients, in the majority this growth does not keep pace with the child’s somatic growth and thus they eventually become obstructive w51x. Placement of a pulmonary artery band appears to accelerate the diminution in size of the BVF w52x. Moreover, the acute volume changes that occur after the Fontan procedure w53x may further exacerbate the outflow obstruction that with time has been reported to progress w54x. The most effective surgical treatment of aortic arch hypoplasia and obstruction has also been debated. In the series of patients reported by Franklin et al. those
Fig. 7. Actuarial survival curves for patients palliated with a Shunt Žsystemic-pulmonary arterial shunt., Band Žbanding of the pulmonary artery trunk. and Coarct Žrepair of an aortic coarctation or interruption with banding of the pulmonary trunk.. The dashed lines refer to survival of the patients before definitive surgery. The 70% confidence limits are shown and the numbers represent the patients remaining from each group still being followed at the time on the x-axis. Žfrom Franklin et al. JTCVS 1991:101Ž5.:919 used with permission. w12x.
who had pulmonary artery banding and repair of the aortic arch obstruction had the poorest outcomes, 44% survival at 1 year and 22% at 5 years w12x ŽFig. 7.. In fact, the hazard rate for the definitive operation showed a two]four-fold higher risk in patients undergoing associated aortic arch repair. This was likely due to the inability to completely relieve the arch obstruction when performed via a left thoracotomy. In the palliative treatment of infants with single ventricle, the complete relief of aortic arch obstruction is important in determining both short- and long-term prognosis. Often the proximal aortic obstruction requires augmentation from the distal ascending aorta to well beyond the insertion of the ductus arteriosus. This procedure is best approached from a median sternotomy using profound hypothermia and a brief period of circulatory arrest, allowing for an extensive mobilization and augmentation of the ascending, transverse and proximal descending thoracic aorta. We recently reviewed our experience with the modified Norwood procedure for the treatment of single left ventricle and VA discordance w36x. Thirty-eight patients with either tricuspid atresia Ž n s 10. or double inlet left ventricle Ž n s 28. and VA discordance underwent the procedure at a mean age of 15 days and a mean weight of 3.4 kg. Aortic arch anomalies were present in 92% of patients. The actuarial survival rates were 89% at one month after surgery, 81% at 1 year and 79% at 5 years. Follow-up studies were carried out in all of the children at a mean interval of 30 " 9 months. None had significant neoaortic valve insufficiency and only one patient required treatment of residual aortic arch obstruction. Most importantly, all surviving patients were found to be excellent can-
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58
didates for the Fontan procedure. Consequently, we join with others in recommending the modified Norwood procedure as the procedure of choice for palliation of infants with this subgroup of single ventricle. The palliative treatment of patients with single left ventricle and L-transposition continues to evolve. Further improvements appear promising as the lessons of earlier surgical strategies are combined with the continued advances in perioperative care of infants with single ventricle lesions associated with shunt-dependent pulmonary blood flow. References w1x Van Praagh R. The segmental approach to diagnosis in congenital heart disease. The fourth conference on the clinical delineation of birth defects Part XV. The cardiovascular system. Birth Defects 1972;8:4]23. w2x Bliddal J. Four cases of congenitally corrected transposition with associated defects. Danish Med Bull 1976;23:184]192. w3x Kidd BL. Congenitally corrected transposition of the great arteries. In: Keith JD, Rowe RD, Vlad P, editors. Heart disease in infancy and childhood. New York: MacMillan, 1978:612]627. w4x Erath HG Jr, Graham Jr. TP, Hammon Jr. JW, Smith CW. Hypoplasia of the systemic ventricle in congenitally corrected transposition of the great arteries; Pre-operative documentation and possible implication of operation. JTCVS 1980; 79:770]775. w5x Anderson RH. Ventricular morphology in the univentricular heart. Herz 1979;4:184. w6x VanPraagh R, Plette JA, VanPraagh S. Single ventricle: Pathology, embryology, terminology, and classification. Herz 1979;4:113]150. w7x VanPraagh R, Ongley PA, Swan HJC. Anatomic types of single or common ventricle in man: Morphologic and geometric aspects of 60 necropsied cases. Am J Cardiol 1964;13:367. w8x Lev M, Liberthson RR, Kirkpatrick JR et al. Single Žprimitive. ventricle. Circulation 1969;39:577. w9x Soto B, Bertranou EG, Bream PR et al. Angiographic study of the univentricular heart of right ventricular type. Circulation 1979;60:1325. w10x Rahimtoula SH, Ongley P, Swan HJC. The hemodynamics of common ventricle. Circulation 1966;34:14. w11x Franklin RCG, Spieglehalter DJ, Anderson RH et al. Double inlet ventricle presenting in infancy. I. Survival without definitive repair. JTCVS 1991;101Ž5.:676]777. w12x Franklin RCG, Spieglehalter DJ, Anderson RH et al. Double inlet ventricle presenting in infancy. II Results of palliative operations. JTCVS 1991;101Ž5.:917]923. w13x Odim J, Portzky M, Zurakowski D et al. Sternotomy approach for the modified Blalock-Taussig shunt. Circulation 1995;92Ž9 Suppl.:II256]II261. w14x Fermanis GG, Ekangaki AK, Solmon AP et al. Twelve year experience with the modified Blalock]Taussig Shunt in neonates. Eur J Cardio-Thorac Surg 1992;6Ž11.:586]589. w15x Webber SA, LeBlanc JG, Keeton BR et al. Pulmonary artery banding is not contraindicated in double inlet left ventricle with transposition and aortic arch obstruction. Eur J CardioThorac Surg 1995;9:515]520. w16x Jensen RA, Williams RG, Laks H et al. Usefulness of banding of the pulmonary trunk with single ventricle physiology at risk of subaortic obstruction. Am J Cardiol 1996;77: 1089]1093.
57
w17x Koh Y, Imai Y, Kurosaua H et al. wPulmonary artery banding for double inlet left ventriclex. Nippon Kyobyu Geka Gakkai Zasshi 1990;38Ž2.:194]200. w18x Freedom RM, Benson LN, Smallhorn JF et al. Subaortic stenosis, the univentricular heart, and banding of the pulmonary artery: An analysis of the course of 43 patients with univentricular heart palliated by pulmonary artery banding. Circulation 1986;73:758]764. w19x Franklin RCG, Sulligan ID, Anderson RH. Is banding of the pulmonary trunk obsolete for infants with tricuspid atresia and double inlet ventricle with a discordant ventriculoarterial connection? Role of aortic arch obstruction and subaortic stenosis. J Am Coll Cardiol 1990;16:1455]1464. w20x Jonas RA, Castaneda AR, Lang P. Single ventricle Žsingle or double-inlet. complicated by subaortic stenosis. Surgical options in infancy. Ann Thorac Surg 1985;39Ž4.:361]365. w21x Ilbawi MN, DeLeon SY, Wilson WR et al. Advantages of early relief of subaortic stenosis in single ventricle equivalents. Ann Thorac Surg 1991;52:842]849. w22x Penkoske PA, Freedom RM, Williams WG et al. Surgical palliation of subaortic stenosis in the univentricular heart. J Thorac Cardiovasc Surg 1984;87:767]781. w23x O’Leary PU, Driscoll DJ, Connor AR et al. Subaortic obstruction in hearts with a univentricular connection to a dominant left ventricle and an anterior subaortic outlet chamber: Results of a staged approach. J Thorac Cardiovasc Surg 1990;106:1231]1238. w24x Cheung HC, Lincoln C, Anderson RH et al. Options for surgical repair in hearts with univentricular atrioventricular connection and subaortic stenosis. J Thorac Cardiovasc Surg 1990;160:672]681. w25x Freedom RM, Dische MR, Rowe RD. Pathologic anatomy of subaortic stenosis and atresia in the first year of life. Am J Cardiol 1977;39:1035]1043. w26x Frommelt DC, Rocchini AP, Bove EL. Natural history of apical left ventricle to aortic conduit in pediatric patients. Circulation 1991;89Žsuppl 3.:217]218. w27x Litwin SB, Van Praagh R, Bernhard WF. A palliative operation for certain infants with aortic arch interruption. Ann Thorac Surg 1972;14:369. w28x Damus PS. Letter to the editor. Ann Thorac Surg 1975; 20:724]725. w29x Kay MP. Anatomic correction for transposition of the great arteries. Mayo Clin Proc 1975;50:638]640. w30x Stansel HC. A new operation for d-loop transposition of the great arteries. Ann Thorac Surg 1975;19:565]567. w31x Lin AE, Laks H, Barber G et al. Subaortic obstruction in complex congenital heart disease, management by proximal pulmonary artery to ascending aorta and to side anastomosis. J Am Coll Cardiol 1986;7:617]624. w32x Lui RC, Williams WG, Trusler GA et al. Experience with the Damus ] Kaye ] Stansel procedure for children with Taussig]Bing hearts or univentricular hearts with subaortic stenosis. Circulation 1993;88Žpt 2.:170]176. w33x Lacour-Gayet F, Serraf A, Formont L et al. Early palliation of univentricular hearts with subaortic stenosis and ventriculoarterial discordance. J Thorac Cardiovasc Surg 1992; 109:1238]1245. w34x Jacobs ML, Rychik J, Donfrio MT. Avoidance of subaortic obstruction in staged management of single ventricle’. Ann Thorac Surg 1995;60Ž6 Suppl.:S543]S545. w35x Van Son JAM, Reddy VM, Haas GS et al. Modified surgical techniques for relief of aortic obstruction in ŽS,L,L. hearts with rudimentary right ventricles and restrictive bulboventricular foramen. J Thorac Cardiovasc Surg 1996;110:909]915. w36x Mosca RS, Hennein HA, Kulik TJ et al. Modified Norwood operation for single left ventricle and ventriculoarterial dis-
58
w37x w38x
w39x w40x
w41x
w42x
w43x w44x
w45x
R.S. Mosca r Progress in Pediatric Cardiology 10 (1999) 51]58 cordance: An improved surgical technique. Ann Thorac Surg 1997;64:1126]1132. Waldmon JD, Lamberti JJ, George L et al. Experience with the Damus procedure. Circulation 1988;78ŽPt 2.:III32]III39. Choussat A, Fontan F, Besse P. Selection criteria for Fontan’s procedure. In: Anderson RH, Shinebourine EA, editors. Paediatric cardiology. Edinburgh: Churchill and Livingstone, 1978:559]566. Kirklin JK, Blackstone EH, Kirklin JW et al. The Fontan operation: Ventricula hypertrophy, age, and date of operation as risk factors. J Thorac Cardiovasc Surg 1986;92:1049. Cetta F, Feldt RH, O’Leary PW et al. Improved early morbidity and mortality after Fontan operation: The Mayo Clinic experience. 1987]1992.. J Am Coll Cardiol 1996;28Ž2.: 480]486. Knott-Craig CJ, Danielson GK, Schaff HV et al. The modified Fontan operation. An analysis of risk factors for early postoperative death or takedown in 702 consecutive patients from one institution. J Thorac Cardiovasc Surg 1995;109Ž6.: 1237]1243. Kalitz R, Zimer G, Luhmer I et al. Modified Fontan operation in functionally univentricular hearts: Preoperative risk factors and intermediate results. J Thorac Cardiovasc Surg 1996;112Ž3.:658]664. Gentles TL, Mayer JE Jr, Gauvreau K et al. Fontan operation in 500 consecutive patients: Factors influencing early and late outcome. J Thorac Cardiovasc Surg 1997;114Ž3.:376]391. Fontan F, Fernandez G, Ebner A. Double inlet univentricular heart: Experience with Fontan procedure. In: Baue AE et al., editor. Glenn’s thoracic and cardiovascular surgery. Norwalk, CT: Appleton and Lange, 1991:1061]1068. Mesko ZG, Jones JE, Nadas AS. Diminution and closure of large ventricular septal defects after pulmonary artery banding. Circulation 1973;48:847]855.
w46x Freedon RM. The dinosaur and banding of the main pulmonary trunk in the in the heart with functionally one ventricle and transposition of the great arteries: A saga of abolition and caution. J Am Coll Cardiol 1987;10:427]429. w47x McKay R, Pacifico AD, Blackstone EH et al. Septation of the univentricular heart with left anterior subaortic outlet chamber. J Thorac Cardiovasc Surg 1982;84:77]87. w48x Carter TL, Mainwaring RD, Lamberti JJ. Damus]Kaye] Stansel procedure: Mid-term follow-up and technical consideration. Ann Thorac Surg 1994;58:1603]1608. w49x Rothmon A, Long P, Lock JE et al. Surgical management of subaortic obstruction in single left ventricle and tricuspid atresia. J Am Coll Cardiol 1987;10Ž2.:421]426. w50x Juaneda E, Haworth SG. Pulmonary vascular structure in patients dying after the Fontan procedure: The lung as a risk factor. Br Heart J 1984;52:575]580. w51x Matitiau A, Geva T, Colan SD et al. Bulboventricular foramen size in infants with double-inlet left ventricle or tricuspid atresia with transposed great arteries: Influence on initial palliative operation and rate of growth. J Am Coll Cardiol 1992;19:142]148. w52x Freedom RM, Sondheiman H, Dische R, Rowe RD. Development of ‘subaortic stenosis’ after pulmonary artery banding for common ventricle. Am J Cardiol 1977;39:78]83. w53x Donofrio MT, Jacobs ML, Norwood WI, Rychik J. Early changes in ventricular septal defect size and ventricular geometry in the single left ventricle after volume-unloading surgery. J Am Coll Cardiol 1995;26:1008]1015. w54x Finta KM, Beekman RH, Lupinetti FM, Bove EL. Ventricular outflow obstruction progresses after the Fontan operation. Ann Thorac Surg 1994;58Ž4.:1108]1113.