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Editorial Comment
Modified Fontan Procedure for Hypoplastic Left Heart Syndrome After Palliation With the Norwood Operation* FRANCISCO J. PUGA, MD, FACC Rochester, Minnesota
The present study. In this issue of the Journal, Chang et al. 0) report on the results of cardiac catheterization in patients with hypoplastic left heart syndrome who had previously undergone a palliative Norwood operation and were being considered for a modified Fontan procedure. This excellent study attempts to delineate preoperative factors that may establish differences between survivors and non survivors of the latter procedure. The report is based on the extensive experience accumulated by the authors 0) with the initial palliative treatment of these infants. It focuses on the cohort of patients who survived the initial operation and underwent elective cardiac catheterization in preparation for definitive surgical repair. Fifty-nine patients met this inclusion criterion. Problems involved in selecting patients for the Norwood operation. The difficulties experienced in attempting to provide palliative treatment for this group of infants include those that continue to result in a high initial operative mortality rate. Additionally, major problems are encountered in preserving the morphologic and hemodynamic variables necessary for inclusion in the selection criteria for the Fontan operation. Given the nature of the anomaly and the technical aspects of the Norwood procedure, the following variables are of significance at the time of elective cardiac catheterization: 1) architecture of the pulmonary artery confluence and its branches; 2) the systolic and diastolic properties of the single functional ventricular chamber; 3) the function of the single atrioventricular (AV) valve; 4) the status of the pulmonary arterioles; and 5) the condition of the atrial septum. Indeed, survivors of the Norwood operation face potential problems in all areas. The extensive reconstruction of the pulmonary artery confluence necessary during the initial palliative operation may result in significant distortion or scarring of the pulmonary arteries, or both. The systolic and diastolic properties of the morphologic right
*Editorials published in Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology. From the Mayo Clinic and Mayo Foundation, Rochester, Minnesota. Address for reprints: Francisco J. Puga, MD, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905. ©1991 by the American College of Cardiology
lACC Vol. 17, No.5
April 1991:1150-1
ventricle can be affected adversely by its architecture, by the volume overload resulting from the common mixing and the systemic to pulmonary shunt and by the pressure overload that may result from residual obstruction to aortic runoff. Atrioventricular valve dysfunction, particularly insufficiency, may further complicate the overall hemodynamic situation. Selection of patients: effect on mortality. In their report, the authors 0) describe a total group of 135 hospital survivors of the Norwood procedure. Yet their data include only 59 of those patients, all of whom underwent a modified Fontan procedure or a superior cavopulmonary anastomosis. We must then assume that the other hospital survivors of initial palliation are not included in this group for several reasons: 1) late mortality, 2) recent palliation (young age), and 3) inadequate anatomic or hemodynamic characteristics for the Fontan procedure as assessed by a method other than cardiac catheterization (echocardiography). A significant number of patients included in their report had undergone interim surgical procedures necessary to correct problems remaining after initial palliation. These included relief of persistent aortic obstruction or shunt revision or atrial septectomy, or both of the latter two procedures. No patient underwent interim reconstruction of pulmonary artery problems or repair of AV valve insufficiency. Analysis of the authors' Table 2 is sobering. For patients without risk factors, the overall mortality rate was 30%. For patients with significant risk factors excluding pulmonary artery distortion, the overall mortality rate was >50%. Indeed, the high risk of the modified Fontan operation in the patients with "no risk factors" may be simply explained by their young age, a recognized risk factor for the Fontan procedure in general (2). Proposed modifications in management protocol. Improvement in these results, as suggested by the authors, may require significant modifications in their management protocol. 1. Delay of the modified Fontan procedure until a more favorable age is attained. If interim palliation is necessary because of increasing cyanosis, the superior cavopulmonary anastomosis appears to be the best alternative. It increases pulmonary artery blood flow and reduces the volume load on the ventricle. 2. Modification of correctable risk factors before the Fontan operation. Interim surgical correction of AV valve insufficiency through valve replacement or annuloplasty is sometimes necessary in an effort to allow optimal recovery of ventricular function before the Fontan operation. The same principle applies to surgical correction of pulmonary artery distortion not amenable to relief through a median sternotomy approach at the time of the Fontan procedure. If pulmonary artery resistance is elevated because of persistent restriction at the level of the atrial septum, time may be required after atrial septectomy for involution of the pulmonary arteriolar vasculature. 0735-1097/911$3.50
PUGA EDITORIAL COMMENT
JACC Vol. 17, No.5 April 1991: 1150-1
3. Refinement of criteria selection for the modified Fontan procedure. Absolute contraindications to the Fontan operation include elevation of pulmonary arteriolar resistance and hypoplasia of the pulmonary arteries. Relative contraindications include young age, pulmonary artery distortion, AV valve insufficiency and "poor" ventricular function (2,3). In selecting patients for the Fontan procedure versus cavopulmonary anastomosis, these considerations must be taken into account. Role of cardiac transplantation. The continuous attrition of these patients at all levels of their palliative surgery continues to be a worrisome feature of this surgical approach. Until further improvement in the results with this staged management protocol can be obtained, other alternatives must be explored. 1. Transplantation in the newborn period continues to be a viable alternative. The limiting factor is the availability of suitable donors and the time constraint imposed by the natural history of hypoplastic left heart syndromes. 2. Consideration of the Norwood operation as a bridge to transplantation, not as a bridge to the Fontan procedure, as currently understood. Certainly, those patients who have
1151
survived the Norwood operation and who do not fit the rigid inclusion criteria for the Fontan procedure must be considered for transplantation (4,5). The authors of this report deserve praise and encouragement for their pioneering work on behalf of this difficult group of patients.
References I. Chang AC, Farrell PE Jr, Murdison KA, et al. Hypoplastic left heart
2.
3.
4.
5.
syndrome: hemodynamic and angiographic assessment after initial reconstructive surgery and relevance to modified Fontan procedure. J Am Coil Cardiol 1991; 17: 1143-9. Danielson GK, Puga FJ, Schaff HV. Surgical treatment of congenital heart disease with modified Fontan procedure. J Jpn Assoc Thorac Surg 1989; 37:831-6. Mair DO. The Fontan procedure: the first 20 years. Curr Opin Pediatr 1989;1:94-9. Bailey LL, Assaad AN, Trimm RF, et al. Orthotopic transplantation during early infancy for incurable congenital heart disease. Ann Surg 1988;208:279-86. Trento A, Griffith BP, Fricker FJ, Kormos RL, Armitage J, Hardesty RL. Lessons learned in pediatric heart transplantation. Ann Thorac Surg 1989;48:617-23.
Editorial Comment
Modified Fontan Procedure for Hypoplastic Left Heart Syndrome After Palliation With the Norwood Operation* FRANCISCO J. PUGA, MD, FACC Rochester, Minnesota
The present study. In this issue of the Journal, Chang et al. 0) report on the results of cardiac catheterization in patients with hypoplastic left heart syndrome who had previously undergone a palliative Norwood operation and were being considered for a modified Fontan procedure. This excellent study attempts to delineate preoperative factors that may establish differences between survivors and non survivors of the latter procedure. The report is based on the extensive experience accumulated by the authors 0) with the initial palliative treatment of these infants. It focuses on the cohort of patients who survived the initial operation and underwent elective cardiac catheterization in preparation for definitive surgical repair. Fifty-nine patients met this inclusion criterion. Problems involved in selecting patients for the Norwood operation. The difficulties experienced in attempting to provide palliative treatment for this group of infants include those that continue to result in a high initial operative mortality rate. Additionally, major problems are encountered in preserving the morphologic and hemodynamic variables necessary for inclusion in the selection criteria for the Fontan operation. Given the nature of the anomaly and the technical aspects of the Norwood procedure, the following variables are of significance at the time of elective cardiac catheterization: 1) architecture of the pulmonary artery confluence and its branches; 2) the systolic and diastolic properties of the single functional ventricular chamber; 3) the function of the single atrioventricular (AV) valve; 4) the status of the pulmonary arterioles; and 5) the condition of the atrial septum. Indeed, survivors of the Norwood operation face potential problems in all areas. The extensive reconstruction of the pulmonary artery confluence necessary during the initial palliative operation may result in significant distortion or scarring of the pulmonary arteries, or both. The systolic and diastolic properties of the morphologic right
*Editorials published in Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology. From the Mayo Clinic and Mayo Foundation, Rochester, Minnesota. Address for reprints: Francisco J. Puga, MD, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905. ©1991 by the American College of Cardiology
lACC Vol. 17, No.5
April 1991:1150-1
ventricle can be affected adversely by its architecture, by the volume overload resulting from the common mixing and the systemic to pulmonary shunt and by the pressure overload that may result from residual obstruction to aortic runoff. Atrioventricular valve dysfunction, particularly insufficiency, may further complicate the overall hemodynamic situation. Selection of patients: effect on mortality. In their report, the authors 0) describe a total group of 135 hospital survivors of the Norwood procedure. Yet their data include only 59 of those patients, all of whom underwent a modified Fontan procedure or a superior cavopulmonary anastomosis. We must then assume that the other hospital survivors of initial palliation are not included in this group for several reasons: 1) late mortality, 2) recent palliation (young age), and 3) inadequate anatomic or hemodynamic characteristics for the Fontan procedure as assessed by a method other than cardiac catheterization (echocardiography). A significant number of patients included in their report had undergone interim surgical procedures necessary to correct problems remaining after initial palliation. These included relief of persistent aortic obstruction or shunt revision or atrial septectomy, or both of the latter two procedures. No patient underwent interim reconstruction of pulmonary artery problems or repair of AV valve insufficiency. Analysis of the authors' Table 2 is sobering. For patients without risk factors, the overall mortality rate was 30%. For patients with significant risk factors excluding pulmonary artery distortion, the overall mortality rate was >50%. Indeed, the high risk of the modified Fontan operation in the patients with "no risk factors" may be simply explained by their young age, a recognized risk factor for the Fontan procedure in general (2). Proposed modifications in management protocol. Improvement in these results, as suggested by the authors, may require significant modifications in their management protocol. 1. Delay of the modified Fontan procedure until a more favorable age is attained. If interim palliation is necessary because of increasing cyanosis, the superior cavopulmonary anastomosis appears to be the best alternative. It increases pulmonary artery blood flow and reduces the volume load on the ventricle. 2. Modification of correctable risk factors before the Fontan operation. Interim surgical correction of AV valve insufficiency through valve replacement or annuloplasty is sometimes necessary in an effort to allow optimal recovery of ventricular function before the Fontan operation. The same principle applies to surgical correction of pulmonary artery distortion not amenable to relief through a median sternotomy approach at the time of the Fontan procedure. If pulmonary artery resistance is elevated because of persistent restriction at the level of the atrial septum, time may be required after atrial septectomy for involution of the pulmonary arteriolar vasculature. 0735-1097/911$3.50
PUGA EDITORIAL COMMENT
JACC Vol. 17, No.5 April 1991: 1150-1
3. Refinement of criteria selection for the modified Fontan procedure. Absolute contraindications to the Fontan operation include elevation of pulmonary arteriolar resistance and hypoplasia of the pulmonary arteries. Relative contraindications include young age, pulmonary artery distortion, AV valve insufficiency and "poor" ventricular function (2,3). In selecting patients for the Fontan procedure versus cavopulmonary anastomosis, these considerations must be taken into account. Role of cardiac transplantation. The continuous attrition of these patients at all levels of their palliative surgery continues to be a worrisome feature of this surgical approach. Until further improvement in the results with this staged management protocol can be obtained, other alternatives must be explored. 1. Transplantation in the newborn period continues to be a viable alternative. The limiting factor is the availability of suitable donors and the time constraint imposed by the natural history of hypoplastic left heart syndromes. 2. Consideration of the Norwood operation as a bridge to transplantation, not as a bridge to the Fontan procedure, as currently understood. Certainly, those patients who have
1151
survived the Norwood operation and who do not fit the rigid inclusion criteria for the Fontan procedure must be considered for transplantation (4,5). The authors of this report deserve praise and encouragement for their pioneering work on behalf of this difficult group of patients.
References I. Chang AC, Farrell PE Jr, Murdison KA, et al. Hypoplastic left heart
2.
3.
4.
5.
syndrome: hemodynamic and angiographic assessment after initial reconstructive surgery and relevance to modified Fontan procedure. J Am Coil Cardiol 1991; 17: 1143-9. Danielson GK, Puga FJ, Schaff HV. Surgical treatment of congenital heart disease with modified Fontan procedure. J Jpn Assoc Thorac Surg 1989; 37:831-6. Mair DO. The Fontan procedure: the first 20 years. Curr Opin Pediatr 1989;1:94-9. Bailey LL, Assaad AN, Trimm RF, et al. Orthotopic transplantation during early infancy for incurable congenital heart disease. Ann Surg 1988;208:279-86. Trento A, Griffith BP, Fricker FJ, Kormos RL, Armitage J, Hardesty RL. Lessons learned in pediatric heart transplantation. Ann Thorac Surg 1989;48:617-23.
