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Hypoplastic left heart syndrome: The norwood procedure and other options
PEDIATRIC
CARDIOLOGY
Norwood I Though operative survival has greatly improved in recent years, this stage continues to incur a significantly greater mortality than the later stages. Reports published for several years following Norwood’s initial description reported a one-month stage I survival no greater than 63% (2). Death usually occurred in the immediate postoperative period, and was frequently due to diminished cardiac output, In the past 5 years, however, early survival following stage I in some centers has increased to 85% (3). Throughout this time, multiple investigators have studied a variety of preoperative and intraoperative variables in an attempt to correlate them with surgical outcome. Barber et al. studied factors of the preoperative period, including age at operation, lowest pH, highest oxygen saturation and history of prior cardiac arrest in the 89 patients in their group (2). They did not find a correlation between any of those factors and early or late survival. Jonas et al., in their analysis of 78 infants, felt that a history of acidosis and a low pH in the immediate preoperative period correlated with an increased hospital mortality (4). They also concluded that anatomic subtype (aortic and mitral valve anatomy) correlated with decreased short-term survival. Infants with stenotic aortic and mitral valves were more likely to have a better late outcome than if the anatomy consisted of atretic aortic and mitral valves. In a subsequent study, the same group also found a birth weight <3 kg to be a risk factor for early mortality. In 1988 Iannettoni et al. reported that an operative age >30 days was a major determinant of mortality (3). Anatomic subtype was not found to be a risk factor in their analysis. Other potential risk factors which have been investigated and not found to be risk factors for early mortality include size of the ascending aorta, right ventricular wall thickness, qualitative function of the RV, and circulatory arrest time (5,6). In our preliminary analysis of 54 patients, we found that neither a prenatal diagnosis nor preoperative hepatic or renal injury correlated with early or late survival (6). In summary, despite multiple reports, no single factor or group of factors have emerged as reproducible predictors of either short- or long-term survival following the Norwood I. Therefore, none of the factors studied could be viewed as an absolute contraindication to palliative surgery. Perhaps of greatest importance, however, is the improved surgical survival, both within individual centers and arnong a greater number of institutions. The explanation for this likely relates to improvements in myocardial preservation, surgical expertise and postoperative management. Occasionally, additional procedures are required prior to the second operative stage. These include shunt revision, enlargement of the atria1 communication and balloon dilatation of a recurrent coarctation. The presence of a late mortality in the months following postoperative discharge has been described by a number of authors. The causes of
BRIEF REVIEW
Hypoplastic Left Heart Syndrome: The Norwood Procedure and Other Options Jeffrey H. Kern, MD and Constance J. Hayes, MD, Columbia-Presbyterian Center, Babies Hospital, New York, New York
Medical
nfants born with hypoplastic left heart syndrome (HLHS) have a small left ventricle and ascending aorta which do not allow for an adequate cardiac output. During prenatal life, survival is possible because systemic blood flow is provided via the ductus arteriosus. Unless a prenatal diagnosis has been made by ultrasound, the condition is frequently not apparent until the ductus arteriosus undergoes spontaneous closure in the first days of life, with subsequent hypoperfusion of vital organs. Without intervention, there is little hope of survival beyond the newborn period. Prior to the early 1980’s, there was no acceptable surgical option to offer these infants. Since that time, however, two surgical alternatives have emerged. One possibility is the staged Norwood procedure, originally described in 1983 (1). The other possibility is neonatal cardiac transplantation. The Norwood
Procedure:
Stages I, II and III
The general principle of the Norwood procedure is the utilization of the right ventricle (RV) as the systemic pumping chamber in the absence of a functional left ventricle (LV). This is accomplished in two or three stages. The first stage (Norwood I) consists of the following components: 1) anastomosis of the proximal pulmonary artery to the ascending aorta; 2) creation of a large atria1 communication to allow unimpeded blood flow from the left atrium (LA) to the right atrium (RA) and RV; 3) resection of the aortic coarctation which is invariably present; and 4) placement of an aortopulmonary shunt as a means of controlled pulmonary blood flow. The second stage (Norwood II) is essentially the bi-directional Glenn procedure. The aorto-pulmonary shunt is taken down, and the superior vena cava is anastomosed to the pulmonary artery confluence. The third operative stage (Norwood III) is the completion of the Fontan procedure, in which the inferior vena caval flow is also directed into the pulmonary artery. At that point, the pulmonary and systemic circulations are completely separate, and the RV provides the entire cardiac output with systemic venous return flowing directly into the pulmonary artery. ACC 0 1997 by the American College of Cardmlogy Published by Elsevier Science Inc.
CURRENT
JOURNAL
REVIEW
79
March/April
1997 1062-1458/97/$17.00 PI1 s1062-1458(97)00014-7
PEDIATRIC
CARDIOLOGY
death in these patients are usually heart failure, shunt thrombosis or infection. Infants with HLHS following the Norwood I operation remain volume-overloaded and shuntdependent with a morphologic RV pumping against systemic pressures. Infections and dehydration which are handled without difficulty by normal babies can be lifethreatening events for infants with HLHS.
No Intervention Allowing the newborn with HLHS to die without surgical intervention or transplant is a third option occasionally offered to families of infants with HLHS. HLHS patients have historically had a lower chance of survival than newborns with other types of congenital heart defects. Many HLHS patients may also have serious pulmonary problems or additional congenital noncardiac abnormalities, including those of the central nervous system (9). There are few reports regarding the neurodevelopmental outcome of HLHS patients following the Norwood procedure. Results of studies in progress suggest a more optimistic outlook for these patients than previously described (10). With increased awareness regarding the improvements in postoperative survival following either the Norwood operation or cardiac transplantation the “no-intervention” option has become a less desirable alternative.
Nor-wood 11and III Published reports have noted that if the infant survives until the second operative stage, the chances of subsequent survival may exceed 90% (3,6). Prior to 1990, many surgeons performed the Fontan procedure, in which the superior and inferior venae cavae were connected to the pulmonary artery, as the second and final stage. Currently, it is felt that a more gradual course towards the Fontan-type circulation is beneficial in these patients and three stages have been employed. Performance of the bidirectional Glenn operation as an intermediate stage allows partial relief of cyanosis and an earlier reduction of the volume load. The completion of the Fontan operation as the third and final stage can be performed electively when the child is 2 to 3 years of age. Postoperative complications are similar to those reported following the bidirectional Glenn and Fontan procedures in other patients with single ventricles, and include pleural effusions, pericardial effusions, and abnormalities of cardiac rhythm.
Conclusion Neonates with HLHS present a formidable challenge to the parents and the medical community. The preferred treatment is not clear-cut and many factors need to be considered, including surgical expertise and available resources. The 3-stage Norwood procedure as surgical treatment for hypoplastic left heart syndrome has met with improved survival in recent years. The S-year actuarial survival rate is 65% in some centers, with the greatest mortality incurred in the first stage. No reproducible risk factor for stage I mortality has been identified. Infants who survive until the second operative stage have a good chance of survival following the completion of the subsequent stages. Cardiac transplantation constitutes another approach to management of the HLHS patient. If not considered initially, transplant may be reserved for the older HLHS infant who is an unsuitable Fontan candidate. A third management choice of “no intervention” remains an option especially in the face of other serious congenital anomalies.
Cardiac Transplantation Neonatal cardiac transplantation is another option which may be offered to infants with HLHS. This option was described at approximately the same time as the Norwood procedure was being refined. The current survival of infants with HLHS listed for transplantation (7) is similar to that described in the most optimistic reports of the stage I Norwood procedure. Included in the transplant mortality is a significant number of infants lost while awaiting transplantation due to the scarce supply of available infant donors. Addonizio et al. compared estimated survival in infants awaiting cardiac transplantation with those undergoing the Norwood procedure (8). They reported a 38% pretransplant mortality in infants awaiting donor hearts. In addition, they noted that the effects of chronic immunosuppression led to repeated admissions in transplant patients which far exceeded readmission in the Norwood group of infants. They concluded that survival and freedom from prolonged cumulative hospital stays favored the Norwood procedure as the initial approach in newborns with HLHS. Cardiac transplantation retains a role in the course of the infant who undergoes the Norwood I operation, but is judged unsuitable for the Fontan procedure. Transplantation can then be considered in an older infant who is often less critically ill and more able to survive the anticipated wait for a donor heart. ACC
CURRENT
JOURNAL
The authors have provided an expanded list of references available upon request to the Editorial Office.
that can be made
REFERENCES 1. Norwood WI, Kirklin JK, Sanders SP. Hypoplastic left heart syndrome: Experience with palliative surgery. Am J Cardiol 1980;45:87-91. 2. Barber G, Chin AJ, Murphy JD, Pigott JD, Norwood WI. Hypoplastic left heart syndrome: Lack of correlation between preoperative demographic and laboratory findings and survival following palliative surgery. Pediatr Cardiol 1989;10:129-34. 3. Iannettoni MD, Bove EL, Mosca RS, et al. Improvmg resuks with first-stage palhation for hypoplastic left heart syndrome. J Thorac Cardtovast Surg 1994;107:934-40. 4. REVIEW
80
Jonas
RA, Hansen
March/Apni
1997
DD,
Cook
N, Wessel
D. Anatomic
subtype
and
PEDIATRIC
survival after reconstructive operation for hypoplastic J Thorac Cardiovasc Surg 1994;107: 1121-8.
CARDIOLOGY
left heart syndrome.
9. Glauser TA, Rorke LB, Weinberg PM, Clancy RR. Congenital brain anomalies associated with the hypoplastic left heart syndrome. Pediatrics 1995;85:984-90.
5. Helton JG, Aghra BA, Chin AJ, Murphy JD, Pigott JD, Norwood WI. Analysis of potential anatomic or physiologic determinants of outcome of palliative surgery for hypoplastic left heart syndrome. Circulation 1986; 74(Suppll):l-70-6.
10. Kern JH. Hinton VJ, Nereo NE, Hayes CJ, Gersony WM. Developmental outcome following surgery for hypoplastic left heart syndrome. Orculation 1996;94(8, suppl 1):652.
6. Kern JH, Hayes CJ, Gersony WM, et al. Hypoplastic left heart syndrome: Survival and risk factor analysis. J Am Co11 Cardiol 1996;27(suppl A):58A. 7. Chiavarelli M, Gundry SR, Rauouk AJ, Bailey LL. Cardiac transplantation for infants with hypoplasuc left-heart syndrome. JAMA 1993;270:2944-7. Address correspondence and reprint requests to: Constance J. Hayes, MD, Columbia-Presbyterian Medical Center, Babies Hospital, Room 255 North, 3959 Broadway, New York, NY 10032.
8. Addonizio L, Hayes CJ, Gersony WM, Hsu DT, Quaegebeur JM, Michler RE. Management of hypoplastic left heart syndrome: Norwood procedure versus transplanatlon. J Heart Lung Transplant 1995;14:547.
ACC
CURRENT
JOURNAL
REVIEW
81
MarchJApnll997
CARDIOLOGY
Norwood I Though operative survival has greatly improved in recent years, this stage continues to incur a significantly greater mortality than the later stages. Reports published for several years following Norwood’s initial description reported a one-month stage I survival no greater than 63% (2). Death usually occurred in the immediate postoperative period, and was frequently due to diminished cardiac output, In the past 5 years, however, early survival following stage I in some centers has increased to 85% (3). Throughout this time, multiple investigators have studied a variety of preoperative and intraoperative variables in an attempt to correlate them with surgical outcome. Barber et al. studied factors of the preoperative period, including age at operation, lowest pH, highest oxygen saturation and history of prior cardiac arrest in the 89 patients in their group (2). They did not find a correlation between any of those factors and early or late survival. Jonas et al., in their analysis of 78 infants, felt that a history of acidosis and a low pH in the immediate preoperative period correlated with an increased hospital mortality (4). They also concluded that anatomic subtype (aortic and mitral valve anatomy) correlated with decreased short-term survival. Infants with stenotic aortic and mitral valves were more likely to have a better late outcome than if the anatomy consisted of atretic aortic and mitral valves. In a subsequent study, the same group also found a birth weight <3 kg to be a risk factor for early mortality. In 1988 Iannettoni et al. reported that an operative age >30 days was a major determinant of mortality (3). Anatomic subtype was not found to be a risk factor in their analysis. Other potential risk factors which have been investigated and not found to be risk factors for early mortality include size of the ascending aorta, right ventricular wall thickness, qualitative function of the RV, and circulatory arrest time (5,6). In our preliminary analysis of 54 patients, we found that neither a prenatal diagnosis nor preoperative hepatic or renal injury correlated with early or late survival (6). In summary, despite multiple reports, no single factor or group of factors have emerged as reproducible predictors of either short- or long-term survival following the Norwood I. Therefore, none of the factors studied could be viewed as an absolute contraindication to palliative surgery. Perhaps of greatest importance, however, is the improved surgical survival, both within individual centers and arnong a greater number of institutions. The explanation for this likely relates to improvements in myocardial preservation, surgical expertise and postoperative management. Occasionally, additional procedures are required prior to the second operative stage. These include shunt revision, enlargement of the atria1 communication and balloon dilatation of a recurrent coarctation. The presence of a late mortality in the months following postoperative discharge has been described by a number of authors. The causes of
BRIEF REVIEW
Hypoplastic Left Heart Syndrome: The Norwood Procedure and Other Options Jeffrey H. Kern, MD and Constance J. Hayes, MD, Columbia-Presbyterian Center, Babies Hospital, New York, New York
Medical
nfants born with hypoplastic left heart syndrome (HLHS) have a small left ventricle and ascending aorta which do not allow for an adequate cardiac output. During prenatal life, survival is possible because systemic blood flow is provided via the ductus arteriosus. Unless a prenatal diagnosis has been made by ultrasound, the condition is frequently not apparent until the ductus arteriosus undergoes spontaneous closure in the first days of life, with subsequent hypoperfusion of vital organs. Without intervention, there is little hope of survival beyond the newborn period. Prior to the early 1980’s, there was no acceptable surgical option to offer these infants. Since that time, however, two surgical alternatives have emerged. One possibility is the staged Norwood procedure, originally described in 1983 (1). The other possibility is neonatal cardiac transplantation. The Norwood
Procedure:
Stages I, II and III
The general principle of the Norwood procedure is the utilization of the right ventricle (RV) as the systemic pumping chamber in the absence of a functional left ventricle (LV). This is accomplished in two or three stages. The first stage (Norwood I) consists of the following components: 1) anastomosis of the proximal pulmonary artery to the ascending aorta; 2) creation of a large atria1 communication to allow unimpeded blood flow from the left atrium (LA) to the right atrium (RA) and RV; 3) resection of the aortic coarctation which is invariably present; and 4) placement of an aortopulmonary shunt as a means of controlled pulmonary blood flow. The second stage (Norwood II) is essentially the bi-directional Glenn procedure. The aorto-pulmonary shunt is taken down, and the superior vena cava is anastomosed to the pulmonary artery confluence. The third operative stage (Norwood III) is the completion of the Fontan procedure, in which the inferior vena caval flow is also directed into the pulmonary artery. At that point, the pulmonary and systemic circulations are completely separate, and the RV provides the entire cardiac output with systemic venous return flowing directly into the pulmonary artery. ACC 0 1997 by the American College of Cardmlogy Published by Elsevier Science Inc.
CURRENT
JOURNAL
REVIEW
79
March/April
1997 1062-1458/97/$17.00 PI1 s1062-1458(97)00014-7
PEDIATRIC
CARDIOLOGY
death in these patients are usually heart failure, shunt thrombosis or infection. Infants with HLHS following the Norwood I operation remain volume-overloaded and shuntdependent with a morphologic RV pumping against systemic pressures. Infections and dehydration which are handled without difficulty by normal babies can be lifethreatening events for infants with HLHS.
No Intervention Allowing the newborn with HLHS to die without surgical intervention or transplant is a third option occasionally offered to families of infants with HLHS. HLHS patients have historically had a lower chance of survival than newborns with other types of congenital heart defects. Many HLHS patients may also have serious pulmonary problems or additional congenital noncardiac abnormalities, including those of the central nervous system (9). There are few reports regarding the neurodevelopmental outcome of HLHS patients following the Norwood procedure. Results of studies in progress suggest a more optimistic outlook for these patients than previously described (10). With increased awareness regarding the improvements in postoperative survival following either the Norwood operation or cardiac transplantation the “no-intervention” option has become a less desirable alternative.
Nor-wood 11and III Published reports have noted that if the infant survives until the second operative stage, the chances of subsequent survival may exceed 90% (3,6). Prior to 1990, many surgeons performed the Fontan procedure, in which the superior and inferior venae cavae were connected to the pulmonary artery, as the second and final stage. Currently, it is felt that a more gradual course towards the Fontan-type circulation is beneficial in these patients and three stages have been employed. Performance of the bidirectional Glenn operation as an intermediate stage allows partial relief of cyanosis and an earlier reduction of the volume load. The completion of the Fontan operation as the third and final stage can be performed electively when the child is 2 to 3 years of age. Postoperative complications are similar to those reported following the bidirectional Glenn and Fontan procedures in other patients with single ventricles, and include pleural effusions, pericardial effusions, and abnormalities of cardiac rhythm.
Conclusion Neonates with HLHS present a formidable challenge to the parents and the medical community. The preferred treatment is not clear-cut and many factors need to be considered, including surgical expertise and available resources. The 3-stage Norwood procedure as surgical treatment for hypoplastic left heart syndrome has met with improved survival in recent years. The S-year actuarial survival rate is 65% in some centers, with the greatest mortality incurred in the first stage. No reproducible risk factor for stage I mortality has been identified. Infants who survive until the second operative stage have a good chance of survival following the completion of the subsequent stages. Cardiac transplantation constitutes another approach to management of the HLHS patient. If not considered initially, transplant may be reserved for the older HLHS infant who is an unsuitable Fontan candidate. A third management choice of “no intervention” remains an option especially in the face of other serious congenital anomalies.
Cardiac Transplantation Neonatal cardiac transplantation is another option which may be offered to infants with HLHS. This option was described at approximately the same time as the Norwood procedure was being refined. The current survival of infants with HLHS listed for transplantation (7) is similar to that described in the most optimistic reports of the stage I Norwood procedure. Included in the transplant mortality is a significant number of infants lost while awaiting transplantation due to the scarce supply of available infant donors. Addonizio et al. compared estimated survival in infants awaiting cardiac transplantation with those undergoing the Norwood procedure (8). They reported a 38% pretransplant mortality in infants awaiting donor hearts. In addition, they noted that the effects of chronic immunosuppression led to repeated admissions in transplant patients which far exceeded readmission in the Norwood group of infants. They concluded that survival and freedom from prolonged cumulative hospital stays favored the Norwood procedure as the initial approach in newborns with HLHS. Cardiac transplantation retains a role in the course of the infant who undergoes the Norwood I operation, but is judged unsuitable for the Fontan procedure. Transplantation can then be considered in an older infant who is often less critically ill and more able to survive the anticipated wait for a donor heart. ACC
CURRENT
JOURNAL
The authors have provided an expanded list of references available upon request to the Editorial Office.
that can be made
REFERENCES 1. Norwood WI, Kirklin JK, Sanders SP. Hypoplastic left heart syndrome: Experience with palliative surgery. Am J Cardiol 1980;45:87-91. 2. Barber G, Chin AJ, Murphy JD, Pigott JD, Norwood WI. Hypoplastic left heart syndrome: Lack of correlation between preoperative demographic and laboratory findings and survival following palliative surgery. Pediatr Cardiol 1989;10:129-34. 3. Iannettoni MD, Bove EL, Mosca RS, et al. Improvmg resuks with first-stage palhation for hypoplastic left heart syndrome. J Thorac Cardtovast Surg 1994;107:934-40. 4. REVIEW
80
Jonas
RA, Hansen
March/Apni
1997
DD,
Cook
N, Wessel
D. Anatomic
subtype
and
PEDIATRIC
survival after reconstructive operation for hypoplastic J Thorac Cardiovasc Surg 1994;107: 1121-8.
CARDIOLOGY
left heart syndrome.
9. Glauser TA, Rorke LB, Weinberg PM, Clancy RR. Congenital brain anomalies associated with the hypoplastic left heart syndrome. Pediatrics 1995;85:984-90.
5. Helton JG, Aghra BA, Chin AJ, Murphy JD, Pigott JD, Norwood WI. Analysis of potential anatomic or physiologic determinants of outcome of palliative surgery for hypoplastic left heart syndrome. Circulation 1986; 74(Suppll):l-70-6.
10. Kern JH. Hinton VJ, Nereo NE, Hayes CJ, Gersony WM. Developmental outcome following surgery for hypoplastic left heart syndrome. Orculation 1996;94(8, suppl 1):652.
6. Kern JH, Hayes CJ, Gersony WM, et al. Hypoplastic left heart syndrome: Survival and risk factor analysis. J Am Co11 Cardiol 1996;27(suppl A):58A. 7. Chiavarelli M, Gundry SR, Rauouk AJ, Bailey LL. Cardiac transplantation for infants with hypoplasuc left-heart syndrome. JAMA 1993;270:2944-7. Address correspondence and reprint requests to: Constance J. Hayes, MD, Columbia-Presbyterian Medical Center, Babies Hospital, Room 255 North, 3959 Broadway, New York, NY 10032.
8. Addonizio L, Hayes CJ, Gersony WM, Hsu DT, Quaegebeur JM, Michler RE. Management of hypoplastic left heart syndrome: Norwood procedure versus transplanatlon. J Heart Lung Transplant 1995;14:547.
ACC
CURRENT
JOURNAL
REVIEW
81
MarchJApnll997