THE WESTERN JOURNAL OF MEDICINE
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SEPTEMBER 1990
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153
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there will be no evidence of cellular damage. At this stage, the marrow hemosiderin levels will not be increased. It is thought that such persons, once their iron stores are returned to normal and kept there, will have no medical effects of their genetic disorder. A strong case can be made for incorporating measurements of the plasma iron, iron-binding capacity, and ferritin into the routine blood screen. A physician's role then will be to interpret these tests and to determine whether parenchymal iron overload is present. Without such a laboratory survey, there is little hope of recognizing hemochromatosis at the time when treatment has the greatest promise. CLEMENT A. FINCH, MD
Professor of Medicine Emeritus University of Washington School of Medicine
Seattle REFERENCES
1. Smith LH Jr: Overview of hemochromatosis. West J Med 1990 153:296-308
Sep;
Transcatheter Treatment of Congenital Heart Disease Past, Present, and Future SINCE THE 1950s, cardiac catheterization has been an impor-
tant tool in the management of congenital or acquired heart disease. Over this 40-year span, changes have occurred not only in the techniques and equipment used to perform a cardiac catheterization in a child, but also over the past 10 years in the indications for cardiac catheterization. In the past, the primary reason for doing a cardiac catheterization was to make an anatomic or physiologic diagnosis. Although the advent of two-dimensional echocardiography and color-flow Doppler has in part replaced this indication, other new indications for cardiac catheterization in pediatric patients have emerged. Two of the major new indications include the following: electrophysiologic studies and therapeutic catheterization. Therapeutic catheterization can be divided into two major types: catheter-based interventions and pharmacologic intervention. The vast majority of therapeutic catheterizations done in children involve catheter-based interventions. The report by Waldman and Swensson elsewhere in this issue clearly summarizes many of these catheter-based therapeutic procedures. I As the authors note, the birth of therapeutic catheterization can be traced to Dr William Rashkind's development of balloon atrial septostomy in the late 1960s.2 The recent development of interventional pediatric cardiology, however, can be linked to two papers published in the early 1980s. Lock and co-workers reported their results in dilating experimentally created peripheral pulmonary artery stenosis in late 1981,3 and about six months later, Kan and colleagues published their results on balloon valvuloplasty for the treatment of pulmonary stenosis.4 Following these and other reports on the use of balloon angioplasty to treat various types of congenital heart disease, it became apparent that more information was needed regarding the techniques, complications, and safety of these new interventional procedures. Therefore, in 1983, pediatric cardiologists from a number of institutions formed the Valvuloplasty and Angiography of Congenital Anomalies (VACA) Registry.5 More than 20 pediatric cardiology centers from around the world participated in this registry. The results of that registry have recently been published in the American Journal of Cardiology.6-10 Based on that report and a number
3
325
of other publications, including the current report of Waldman and Swensson, it is clear that balloon dilation is an effective, safe form of therapy for children with many forms of congenital heart disease, including valvar pulmonary, tricuspid, mitral, and aortic stenosis; coarctation of the aorta; peripheral pulmonary artery stenosis; and superior vena caval obstruction. There are, however, still a number of areas related to balloon angioplasty that need further evaluation. These include the following: long-term follow-up results, the use of these interventional techniques in infants, the socioeconomic benefits of these interventional techniques, and the combined use of interventional cardiology and cardiac surgery in the treatment of some forms of congenital heart disease. To date, most of the data regarding the efficacy of angioplasty to treat congenital heart disease relate to initial or short-term-less than two years after angioplasty-hemodynamic studies. There have been no long-term studiesmore than five years after intervention-that have documented that these interventional procedures provide long-lasting hemodynamic and angiographic correction of the congenital defect. To establish the efficacy of balloon angioplasty, these long-term studies will need to be done. With regard to the use of these interventional techniques in infants, available data suggest that balloon valvuloplasty is safe and efficacious for the treatment of critical pulmonary stenosis in neonates. The use of balloon valvuloplasty to treat critical aortic stenosis in neonates is less clear, however.11.12 Based on the findings of the VACA registry, valvuloplasty results in the same degree of aortic stenosis gradient reduction in children regardless of whether they are older or younger than 1 year. The incidence of significant complications, however, including death, aortic regurgitation, and femoral artery damage, is inversely related to the age of the child, with valvuloplasty performed during the first month of life having the highest rate of complications.' A major reason why infants and neonates have higher complication rates is thought to relate to the combination of the larger size (10 to 12 French) of the currently available valvuloplasty catheters and the relatively small size of infants' femoral vessels. In the future, with the development of new catheters with a smaller shaft size and lower balloon profile, valvuloplasty for aortic stenosis will be performed safely in most neonates and infants. As well summarized by Waldman and Swensson, there are both major socioeconomic benefits and problems associated with interventional pediatric cardiology. The major benefits include shorter hospital stays, less need for blood transfusion, the lack of a surgical scar and the psychological trauma that entails, and the potential for large financial savings in an already overspent health care market. Major new problems that interventional cardiology has created include obtaining acceptance from third-party payers that these interventional procedures are no longer experimental and are therefore reimbursable; the need to regulate the indications for performing these procedures; the need to develop standards regarding accreditation for training pediatric cardiologists in these interventional procedures; and the need to establish guidelines for regulating which hospitals should be permitted to do these procedures. The final area for which future research is needed relates to the interrelationship between interventional cardiology and cardiac surgery. In the past, before the use of a new interventional procedure was advocated, the catheter intervention was required to be able to replace surgical therapy as the treatment of choice; that is, the results of the intervention had to be as good or better than surgical treatment.
326
This is not the only way to judge the usefulness and merit of an interventional procedure, however. For example, at the University of Michigan we have been advocating the following approach to native coarctation of the aorta in children: If a child has a discrete isolated thoracic coarctation of the aorta, we recommend that balloon angioplasty be done as the initial procedure. If the angioplasty is unsuccessful (that is, if the resting systolic gradient between ascending and descending aortic pressures of more than 20 mm of mercury persists longer than three months after angioplasty, with or without upper extremity hypertension) then an operation is done. Using this approach, we have successfully and safely treated 55 children with coarctation of a native aorta (45 have required angioplasty alone and 10 have required angioplasty and subsequent surgical correction. In addition, there has been no increased operative morbidity in children who have had a previous angioplasty of a native aortic coarctation). Thus even though balloon angioplasty is effective in only 80% of children with native coarctation, there is still an important place for balloon angioplasty in the management of native coarctation of the aorta."3 Another example of the interrelationship between interventional cardiology and surgery occurs in children with pulmonary atresia, a ventricular septal defect, and multiple collateral vessels. In this lesion, neither catheter intervention alone nor surgical treatment alone is usually capable of adequately treating a patient. Catheter intervention is usually necessary to occlude collateral vessels and dilate stenotic peripheral pulmonary arteries, and surgical intervention is necessary to establish continuity between the right ventricle and pulmonary arteries and ultimately close the ventricular septal defects. In the future, more and more children with complex cardiovascular lesions will require the combined use of interventional cardiology and surgery. In summary, over the past 40 years pediatric cardiologists have made remarkable progress in developing a nonsurgical method for treating various forms of congenital heart disease. With further modification of existing procedures, the validation of interventional procedures that are
EDITORIALS EDITORIALS~~~~~~~~~
currently experimental-such as transcatheter closure of septal defects, transcatheter closure of patent ductus arteriosus, and the use of balloon expandable intravascular stents-and the development of even newer procedures, interventional catheterization alone or in combination with a surgical procedure will become the standard of care for the majority of children with congenital heart disease. ALBERT P. ROCCHINI, MD Division of Pediatric Cardiology C. S. Mott Children's Hospital University of Michigan Medical Center Ann Arbor REFERENCES 1. Waldman JD, Swensson RE: Therapeutic cardiac catheterization in children. West J Med 1990 Sep; 153:288-295 2. Rashkind WJ, Miller WW: Creation of an atrial septal defect without thoracotomy: Palliative approach to complete transposition of the great arteries. JAMA 1966; 196:991-992 3. Lock JE, Niemi T, Einzig S, et al: Transvenous angioplasty of experimental branch pulmonary artery stenosis in newborn lambs. Circulation 1981; 64:886893 4. Kan JS, White RI, Mitchell SE, et al: Percutaneous balloon valvuloplasty: A new method for treating congenital pulmonary valve stenosis. N Engl J Med 1982; 307:540-542 5. Allen HD, Mullins CE: Results of the Valvuloplasty and Angioplasty of Congenital Anomalies (VACA) Registry: Introduction. Am J Cardiol 1990; 65:722 6. Kan JS, Marvin WJ, Bass JL, et al: Balloon angioplasty-Branch pulmonary artery stenosis: Results from the Valvuloplasty and Angioplasty of Congenital Anomalies Registry. Am J Cardiol 1990; 65:798-801 7. Rocchini AP, Beekman RH, Shachar GB, et al: Balloon aortic valvuloplasty: Results from the Valvuloplasty and Angioplasty of Congenital Anomalies Registry. Am J Cardiol 1990; 65:784-789 8. Tynan M, Finley JP, Fontes V, et al: Balloon angioplasty for the treatment of native coarctation: Results from the Valvuloplasty and Angioplasty of Congenital Anomalies Registry. Am J Cardiol 1990; 65:790-792 9. Hellenbrand WE, Allen HD, Golinko RJ, et al: Balloon angioplasty for aortic recoarctation: Results from the Valvuloplasty and Angioplasty of Congenital Anomalies Registry. Am J Cardiol 1990; 65:793-797 10. Stanger P, Cassidy SC, Girod DA, et al: Balloon pulmonary valvuloplasty: Results from the Valvuloplasty and Angioplasty of Congenital Anomalies Registry. Am J Cardiol 1990; 65:775-783 11. Zeevi B, Keane JF, Castenada AR, et al: Neonatal critical valvar aortic stenosis: A comparison of surgical and balloon dilation therapy. Circulation 1989; 80:831-839 12. Freedom RM: Balloon therapy of critical aortic stenosis in the neonate: The therapeutic conundrum resolved? Circulation 1989; 80:1087-1088 13. Beekman RH, Rocchini AP: Transcatheter treatment of congenital heart disease. Prog Cardiovasc Dis 1989; 32:1-30
o
SEPTEMBER 1990
*
153
o
there will be no evidence of cellular damage. At this stage, the marrow hemosiderin levels will not be increased. It is thought that such persons, once their iron stores are returned to normal and kept there, will have no medical effects of their genetic disorder. A strong case can be made for incorporating measurements of the plasma iron, iron-binding capacity, and ferritin into the routine blood screen. A physician's role then will be to interpret these tests and to determine whether parenchymal iron overload is present. Without such a laboratory survey, there is little hope of recognizing hemochromatosis at the time when treatment has the greatest promise. CLEMENT A. FINCH, MD
Professor of Medicine Emeritus University of Washington School of Medicine
Seattle REFERENCES
1. Smith LH Jr: Overview of hemochromatosis. West J Med 1990 153:296-308
Sep;
Transcatheter Treatment of Congenital Heart Disease Past, Present, and Future SINCE THE 1950s, cardiac catheterization has been an impor-
tant tool in the management of congenital or acquired heart disease. Over this 40-year span, changes have occurred not only in the techniques and equipment used to perform a cardiac catheterization in a child, but also over the past 10 years in the indications for cardiac catheterization. In the past, the primary reason for doing a cardiac catheterization was to make an anatomic or physiologic diagnosis. Although the advent of two-dimensional echocardiography and color-flow Doppler has in part replaced this indication, other new indications for cardiac catheterization in pediatric patients have emerged. Two of the major new indications include the following: electrophysiologic studies and therapeutic catheterization. Therapeutic catheterization can be divided into two major types: catheter-based interventions and pharmacologic intervention. The vast majority of therapeutic catheterizations done in children involve catheter-based interventions. The report by Waldman and Swensson elsewhere in this issue clearly summarizes many of these catheter-based therapeutic procedures. I As the authors note, the birth of therapeutic catheterization can be traced to Dr William Rashkind's development of balloon atrial septostomy in the late 1960s.2 The recent development of interventional pediatric cardiology, however, can be linked to two papers published in the early 1980s. Lock and co-workers reported their results in dilating experimentally created peripheral pulmonary artery stenosis in late 1981,3 and about six months later, Kan and colleagues published their results on balloon valvuloplasty for the treatment of pulmonary stenosis.4 Following these and other reports on the use of balloon angioplasty to treat various types of congenital heart disease, it became apparent that more information was needed regarding the techniques, complications, and safety of these new interventional procedures. Therefore, in 1983, pediatric cardiologists from a number of institutions formed the Valvuloplasty and Angiography of Congenital Anomalies (VACA) Registry.5 More than 20 pediatric cardiology centers from around the world participated in this registry. The results of that registry have recently been published in the American Journal of Cardiology.6-10 Based on that report and a number
3
325
of other publications, including the current report of Waldman and Swensson, it is clear that balloon dilation is an effective, safe form of therapy for children with many forms of congenital heart disease, including valvar pulmonary, tricuspid, mitral, and aortic stenosis; coarctation of the aorta; peripheral pulmonary artery stenosis; and superior vena caval obstruction. There are, however, still a number of areas related to balloon angioplasty that need further evaluation. These include the following: long-term follow-up results, the use of these interventional techniques in infants, the socioeconomic benefits of these interventional techniques, and the combined use of interventional cardiology and cardiac surgery in the treatment of some forms of congenital heart disease. To date, most of the data regarding the efficacy of angioplasty to treat congenital heart disease relate to initial or short-term-less than two years after angioplasty-hemodynamic studies. There have been no long-term studiesmore than five years after intervention-that have documented that these interventional procedures provide long-lasting hemodynamic and angiographic correction of the congenital defect. To establish the efficacy of balloon angioplasty, these long-term studies will need to be done. With regard to the use of these interventional techniques in infants, available data suggest that balloon valvuloplasty is safe and efficacious for the treatment of critical pulmonary stenosis in neonates. The use of balloon valvuloplasty to treat critical aortic stenosis in neonates is less clear, however.11.12 Based on the findings of the VACA registry, valvuloplasty results in the same degree of aortic stenosis gradient reduction in children regardless of whether they are older or younger than 1 year. The incidence of significant complications, however, including death, aortic regurgitation, and femoral artery damage, is inversely related to the age of the child, with valvuloplasty performed during the first month of life having the highest rate of complications.' A major reason why infants and neonates have higher complication rates is thought to relate to the combination of the larger size (10 to 12 French) of the currently available valvuloplasty catheters and the relatively small size of infants' femoral vessels. In the future, with the development of new catheters with a smaller shaft size and lower balloon profile, valvuloplasty for aortic stenosis will be performed safely in most neonates and infants. As well summarized by Waldman and Swensson, there are both major socioeconomic benefits and problems associated with interventional pediatric cardiology. The major benefits include shorter hospital stays, less need for blood transfusion, the lack of a surgical scar and the psychological trauma that entails, and the potential for large financial savings in an already overspent health care market. Major new problems that interventional cardiology has created include obtaining acceptance from third-party payers that these interventional procedures are no longer experimental and are therefore reimbursable; the need to regulate the indications for performing these procedures; the need to develop standards regarding accreditation for training pediatric cardiologists in these interventional procedures; and the need to establish guidelines for regulating which hospitals should be permitted to do these procedures. The final area for which future research is needed relates to the interrelationship between interventional cardiology and cardiac surgery. In the past, before the use of a new interventional procedure was advocated, the catheter intervention was required to be able to replace surgical therapy as the treatment of choice; that is, the results of the intervention had to be as good or better than surgical treatment.
326
This is not the only way to judge the usefulness and merit of an interventional procedure, however. For example, at the University of Michigan we have been advocating the following approach to native coarctation of the aorta in children: If a child has a discrete isolated thoracic coarctation of the aorta, we recommend that balloon angioplasty be done as the initial procedure. If the angioplasty is unsuccessful (that is, if the resting systolic gradient between ascending and descending aortic pressures of more than 20 mm of mercury persists longer than three months after angioplasty, with or without upper extremity hypertension) then an operation is done. Using this approach, we have successfully and safely treated 55 children with coarctation of a native aorta (45 have required angioplasty alone and 10 have required angioplasty and subsequent surgical correction. In addition, there has been no increased operative morbidity in children who have had a previous angioplasty of a native aortic coarctation). Thus even though balloon angioplasty is effective in only 80% of children with native coarctation, there is still an important place for balloon angioplasty in the management of native coarctation of the aorta."3 Another example of the interrelationship between interventional cardiology and surgery occurs in children with pulmonary atresia, a ventricular septal defect, and multiple collateral vessels. In this lesion, neither catheter intervention alone nor surgical treatment alone is usually capable of adequately treating a patient. Catheter intervention is usually necessary to occlude collateral vessels and dilate stenotic peripheral pulmonary arteries, and surgical intervention is necessary to establish continuity between the right ventricle and pulmonary arteries and ultimately close the ventricular septal defects. In the future, more and more children with complex cardiovascular lesions will require the combined use of interventional cardiology and surgery. In summary, over the past 40 years pediatric cardiologists have made remarkable progress in developing a nonsurgical method for treating various forms of congenital heart disease. With further modification of existing procedures, the validation of interventional procedures that are
EDITORIALS EDITORIALS~~~~~~~~~
currently experimental-such as transcatheter closure of septal defects, transcatheter closure of patent ductus arteriosus, and the use of balloon expandable intravascular stents-and the development of even newer procedures, interventional catheterization alone or in combination with a surgical procedure will become the standard of care for the majority of children with congenital heart disease. ALBERT P. ROCCHINI, MD Division of Pediatric Cardiology C. S. Mott Children's Hospital University of Michigan Medical Center Ann Arbor REFERENCES 1. Waldman JD, Swensson RE: Therapeutic cardiac catheterization in children. West J Med 1990 Sep; 153:288-295 2. Rashkind WJ, Miller WW: Creation of an atrial septal defect without thoracotomy: Palliative approach to complete transposition of the great arteries. JAMA 1966; 196:991-992 3. Lock JE, Niemi T, Einzig S, et al: Transvenous angioplasty of experimental branch pulmonary artery stenosis in newborn lambs. Circulation 1981; 64:886893 4. Kan JS, White RI, Mitchell SE, et al: Percutaneous balloon valvuloplasty: A new method for treating congenital pulmonary valve stenosis. N Engl J Med 1982; 307:540-542 5. Allen HD, Mullins CE: Results of the Valvuloplasty and Angioplasty of Congenital Anomalies (VACA) Registry: Introduction. Am J Cardiol 1990; 65:722 6. Kan JS, Marvin WJ, Bass JL, et al: Balloon angioplasty-Branch pulmonary artery stenosis: Results from the Valvuloplasty and Angioplasty of Congenital Anomalies Registry. Am J Cardiol 1990; 65:798-801 7. Rocchini AP, Beekman RH, Shachar GB, et al: Balloon aortic valvuloplasty: Results from the Valvuloplasty and Angioplasty of Congenital Anomalies Registry. Am J Cardiol 1990; 65:784-789 8. Tynan M, Finley JP, Fontes V, et al: Balloon angioplasty for the treatment of native coarctation: Results from the Valvuloplasty and Angioplasty of Congenital Anomalies Registry. Am J Cardiol 1990; 65:790-792 9. Hellenbrand WE, Allen HD, Golinko RJ, et al: Balloon angioplasty for aortic recoarctation: Results from the Valvuloplasty and Angioplasty of Congenital Anomalies Registry. Am J Cardiol 1990; 65:793-797 10. Stanger P, Cassidy SC, Girod DA, et al: Balloon pulmonary valvuloplasty: Results from the Valvuloplasty and Angioplasty of Congenital Anomalies Registry. Am J Cardiol 1990; 65:775-783 11. Zeevi B, Keane JF, Castenada AR, et al: Neonatal critical valvar aortic stenosis: A comparison of surgical and balloon dilation therapy. Circulation 1989; 80:831-839 12. Freedom RM: Balloon therapy of critical aortic stenosis in the neonate: The therapeutic conundrum resolved? Circulation 1989; 80:1087-1088 13. Beekman RH, Rocchini AP: Transcatheter treatment of congenital heart disease. Prog Cardiovasc Dis 1989; 32:1-30
