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Unusual coronary patterns and arterial switch outcome
Unusual Coronary Patterns and Arterial Switch Outcome Ronald W. Day, MD Division of Pediatric Cardiology, University of Utah, Primary Children’s Medical Center, Salt Lake City, Utah
D
uring the past decade, the arterial switch operation has emerged as the treatment of choice for newborns with d-transposition of the great arteries. From 1985 to 1989, a prospective multiinstitutional study was designed by The Congenital Heart Surgeons Society to collect detailed information concerning the outcome and risk factors of the arterial switch operation. Intermediate results from this study were recently reported by Kirklin and associates [l].They reported the following risk factors for death: Multiple ventricular septa1 defects. Origin of the left main coronary artery or origin of only the circumflex or anterior descending coronary artery from sinus 2. This often implies a right coronary artery course anterior to the great arteries. An intramural coronary arterial segment. Longer global myocardial ischemia and circulatory arrest times. Certain institutions. The patients in this study were not randomized with respect to initial surgical therapy. However, the study may provide important information concerning the outcome of patients managed by the arterial switch operation and alternative atrial switch operations. Some institutions with The Congenital Heart Surgeons Society study have favorable outcomes of anatomic correction of d-transposition of the great arteries with all coronary patterns. In this issue of The Annals of Thoracic Surgery, authors from the Mayo Clinic and Royal Children’s Hospital
See also pages 458 and 461. ~
report their experience with intramural coronary artery segments in candidates for the arterial switch operation. Sim and associates [2] describe 3 of their patients and review from the literature more than 25 additional cases of intramural coronary arteries. They conclude that an intramural coronary artery segment must be suspected if the vessel passes between the great arteries. Asou and associates [3] report their results with the arterial switch operation and describe a technique of intramural coronary artery transfer that involves the enlargement of stenotic coronary orifices and resuspension of the posterior neoAddress reprint requests to Dr Day, Division of Pediatric Cardiology, Primary Children’s Medical Center, 100 N Medical Dr, Salt Lake City, UT 84113.
0 1994 by The Society of Thoracic Surgeons
pulmonary valve commissure. None of their patients (n = 12) with an intramural coronary artery has died or had development of abnormalities on electrocardiograms or echocardiograms. Coronary patency was confirmed by angiography in only 6 of these patients. At their institution, preoperative diagnosis of coronary anatomy was not reliably predicted by echocardiography or angiography. An intramural coronary course is only occasionally associated with d-transposition of the great arteries [4].In most of these cases, the intramural segment passes horizontally between the great arteries. However, a vertical intramural course of the left coronary artery within sinus 1 has also been described [3, 51. Anomalous coronary origins with a proximal course between the great arteries also rarely occur with atrioventricular and ventriculoarterial concordance [6]. Several descriptions of this anomaly have failed to state whether all coronary segments passing between the great arteries were ”intramural” (based on a lack of interposed adventitia between the aorta and coronary artery). This anomaly is a potential cause of sudden death in patients with otherwise normal hearts [7].Sim and associates propose that an intramural course should be assumed when a coronary artery passes between the aorta and pulmonary artery in d-transposition of the great arteries. This generalization may eventually be disproved. Of note, Asou and associates list 2 patients in their series with coronary arteries passing between the great arteries that were not considered “intramural.” Further, successful reimplantation of a coronary artery passing between the great arteries may be challenging whether or not a true intramural segment is present. The results of Asou and associates are highly commendable. They have shown a low early mortality for the arterial switch operation independent of coronary anatomy. There was no difference in early survival between the techniques used to manage intramural coronary arteries in this series. In theory, the risk of compression of an intramural segment is not alleviated by modifications of the arterial switch operation that simply overlay a patch from the neoaortic root to an anterior or superior facing coronary button. As described by Asou and associates, coronary flow and orifice growth may be improved by unroofing an intramural segment; however, the potential of scarring and restenosis has not been excluded. All of the patients with intramural coronary arteries in this series are alive and asymptomatic with normal electrocardiograms and echocardiograms. Six of these 12 patients have normal coronary filling by aortography. UnfortuAnn Thorac Surg 1994;57283-5
0003-4975/94/$7.00
284
EDITORIAL DAY INTRAMURAL CORONARY ARTERIES
Ann Thorac Surg 1994;5728>5
cx
D
\’
AD
Fig 1 . Antegrade selective coronary arteriography of an unusual single coronary pattern in a patient with d-transposition of the great arteries in ( A ) the right anterior oblique, ( B ) the posterior-anterior, and (C) the long-axis oblique projections with illustration (D). Using a modified Leiden classification, this is a single coronary origin (2R, AD, Cx) with the left coronary artery passing anterior to the great arteries and a perforating septal branch passing between the great arteries. If an arterial switch operation were considered in this patient, the technique of coronay reimplantation may be influenced by foreknowledge of the course of the septal branch. Transfer of the coronary artery to the neoaortic root may result in excessive tension or torsion on the septal branch. Septa1 ischemia could result in ventricular dysfunction or conduction abnormalities. The origin and course of the initial septal branch in this patient was not detected by echocardiography or by aortic root angiography with balloon occlusion using the laid-back projection. (AD = anterior descending coronary artery; Cx = circumflex artery; RCA = right coronary artery.)
nately, proximal coronary artery stenosis may be missed by an aortogram, and patients with coronary occlusion may be asymptomatic with normal resting electrocardiograms and echocardiograms after an arterial switch operation [8, 91. Thus, Asou and associates can only speculate that the intramural coronary arteries in their patients are currently patent and free of stenoses. Asou and associates strongly suggest that all coronary patterns are amenable to translocation with no difference in risk. However, even their expertise may be overstated. If only patients with d-transposition of the great arteries are considered in their series, risk of operative mortality for patients with a right coronary artery course anterior to the great arteries was low, but significantly greater than the risk of operative mortality for patients with the two most common coronary patterns (Fisher exact text, p = 0.049).
A collaborative study has identified coronary patterns that increase the risk of the arterial switch operation [l]. Thus, accurate preoperative and postoperative evaluations of coronary anatomy and perfusion may be of value in planning and interpreting the outcome of various surgical procedures for d-transposition of the great arteries (Fig 1).Coronary anatomy can be described accurately and safely by several echocardiographic and angiographic methods. In some institutions, the arterial switch operation is presently performed independent of the coronary anatomy. In other institutions, patients with unusual coronary patterns are palliated by balloon atrial septostomy and treated with an atrial switch operation later in infancy. An equivalent risk for neonatal and infant atrial switch operations has not been reported. A longterm, randomized, prospective study could test the hypothesis that the outcomes of arterial and atrial switch
EDITORIAL DAY INTRAMURAL CORONARY ARTERIES
Ann Thorac Surg 1994;57283-5
approaches are different for patients with unusual coronary patterns. However, individual institutions may not have sufficient patients to determine differences in outcome, and a multicenter study may be limited by institutional differences in the results of both arterial and atrial switch procedures. Thus, the long-term superiority of one technique may never be resolved for the subgroup of patients with unusual coronary patterns. Uniform guidelines have not been defined for the long-term follow-up of coronary perfusion in arterial switch patients. If follow-up evaluations are not performed and symptoms of coronary occlusion develop over a prolonged interval in some patients, we may fail to identify risk factors of potential value to future arterial switch candidates for several years. Many tests of coronary perfusion are somewhat invasive, costly, or of limited availability. However, the long-term effects of coronary reimplantation on vessel growth and myocardial perfusion are unknown. Thus, noninvasive evaluations of myocardial perfusion and function (at rest and with exertion or pharmacological stress), and a heart catheterization with coronary angiography may be justified in all patients 1 year after operation and during adolescence. Many talented surgeons are responsible for the encouraging early and intermediate results of the arterial switch operation. Ongoing studies may confirm that the longterm outcome of all patients with transposition can be improved as a result of their innovative efforts.
285
References 1. Kirklin JW, Blackstone EH, Tchervenkov CI, Castaneda AR.
Clinical outcomes after the arterial switch operation for transposition: patient, support, procedural, and institutional risk factors. Circulation 1992;86:1501-15. 2. Sim EKW, van Son JAM, Julsrud PR, Puga FJ. Aortic intramural course of the left coronary artery in dextro-transposition of the great arteries. Ann Thorac Surg 1994;57:458-60. 3. Asou T, Karl TR, Pawade A, Mee RBB. Arterial switch: translocation of the intramural coronary artery. Ann Thorac Surg 1994;57461-5. 4. Shaher RM, Puddu GC. Coronary arterial anatomy in complete transposition of the great arteries. Am J Cardiol 1966;17: 35541. 5. Gittenberger-de Groot AC, Sauer U, Quaegebeur J. Aortic intramural coronary artery in three hearts with transposition of the great arteries. J Thorac Cardiovasc Surg 1986;91:566-71. 6. Vlodaver Z, Neufeld HN, Edwards JE. Pathology of coronary disease. Semin Roentgen01 1972;7376-94. 7. Mustafa I, Gula G, Radley-Smith R, Durrer S, Yacoub M.
Anomalous origin of the left coronary from the anterior aortic sinus: a potential cause of sudden death. J Thorac Cardiovasc Surg 1981;82:297-300. 8. Wernovsky G, Hougen TJ, Walsh EP, et al. Midterm results after the arterial switch operation for transposition of the great arteries with intact ventricular septum: clinical, hemodynamic, echocardiographic, and electrophysiological data. Circulation 1988;77:133344. 9. Day RW, Laks H, Drinkwater DC. The influence of coronary anatomy on the arterial switch operation in neonates. J Thorac Cardiovasc Surg 1992;104:706-12.
D
uring the past decade, the arterial switch operation has emerged as the treatment of choice for newborns with d-transposition of the great arteries. From 1985 to 1989, a prospective multiinstitutional study was designed by The Congenital Heart Surgeons Society to collect detailed information concerning the outcome and risk factors of the arterial switch operation. Intermediate results from this study were recently reported by Kirklin and associates [l].They reported the following risk factors for death: Multiple ventricular septa1 defects. Origin of the left main coronary artery or origin of only the circumflex or anterior descending coronary artery from sinus 2. This often implies a right coronary artery course anterior to the great arteries. An intramural coronary arterial segment. Longer global myocardial ischemia and circulatory arrest times. Certain institutions. The patients in this study were not randomized with respect to initial surgical therapy. However, the study may provide important information concerning the outcome of patients managed by the arterial switch operation and alternative atrial switch operations. Some institutions with The Congenital Heart Surgeons Society study have favorable outcomes of anatomic correction of d-transposition of the great arteries with all coronary patterns. In this issue of The Annals of Thoracic Surgery, authors from the Mayo Clinic and Royal Children’s Hospital
See also pages 458 and 461. ~
report their experience with intramural coronary artery segments in candidates for the arterial switch operation. Sim and associates [2] describe 3 of their patients and review from the literature more than 25 additional cases of intramural coronary arteries. They conclude that an intramural coronary artery segment must be suspected if the vessel passes between the great arteries. Asou and associates [3] report their results with the arterial switch operation and describe a technique of intramural coronary artery transfer that involves the enlargement of stenotic coronary orifices and resuspension of the posterior neoAddress reprint requests to Dr Day, Division of Pediatric Cardiology, Primary Children’s Medical Center, 100 N Medical Dr, Salt Lake City, UT 84113.
0 1994 by The Society of Thoracic Surgeons
pulmonary valve commissure. None of their patients (n = 12) with an intramural coronary artery has died or had development of abnormalities on electrocardiograms or echocardiograms. Coronary patency was confirmed by angiography in only 6 of these patients. At their institution, preoperative diagnosis of coronary anatomy was not reliably predicted by echocardiography or angiography. An intramural coronary course is only occasionally associated with d-transposition of the great arteries [4].In most of these cases, the intramural segment passes horizontally between the great arteries. However, a vertical intramural course of the left coronary artery within sinus 1 has also been described [3, 51. Anomalous coronary origins with a proximal course between the great arteries also rarely occur with atrioventricular and ventriculoarterial concordance [6]. Several descriptions of this anomaly have failed to state whether all coronary segments passing between the great arteries were ”intramural” (based on a lack of interposed adventitia between the aorta and coronary artery). This anomaly is a potential cause of sudden death in patients with otherwise normal hearts [7].Sim and associates propose that an intramural course should be assumed when a coronary artery passes between the aorta and pulmonary artery in d-transposition of the great arteries. This generalization may eventually be disproved. Of note, Asou and associates list 2 patients in their series with coronary arteries passing between the great arteries that were not considered “intramural.” Further, successful reimplantation of a coronary artery passing between the great arteries may be challenging whether or not a true intramural segment is present. The results of Asou and associates are highly commendable. They have shown a low early mortality for the arterial switch operation independent of coronary anatomy. There was no difference in early survival between the techniques used to manage intramural coronary arteries in this series. In theory, the risk of compression of an intramural segment is not alleviated by modifications of the arterial switch operation that simply overlay a patch from the neoaortic root to an anterior or superior facing coronary button. As described by Asou and associates, coronary flow and orifice growth may be improved by unroofing an intramural segment; however, the potential of scarring and restenosis has not been excluded. All of the patients with intramural coronary arteries in this series are alive and asymptomatic with normal electrocardiograms and echocardiograms. Six of these 12 patients have normal coronary filling by aortography. UnfortuAnn Thorac Surg 1994;57283-5
0003-4975/94/$7.00
284
EDITORIAL DAY INTRAMURAL CORONARY ARTERIES
Ann Thorac Surg 1994;5728>5
cx
D
\’
AD
Fig 1 . Antegrade selective coronary arteriography of an unusual single coronary pattern in a patient with d-transposition of the great arteries in ( A ) the right anterior oblique, ( B ) the posterior-anterior, and (C) the long-axis oblique projections with illustration (D). Using a modified Leiden classification, this is a single coronary origin (2R, AD, Cx) with the left coronary artery passing anterior to the great arteries and a perforating septal branch passing between the great arteries. If an arterial switch operation were considered in this patient, the technique of coronay reimplantation may be influenced by foreknowledge of the course of the septal branch. Transfer of the coronary artery to the neoaortic root may result in excessive tension or torsion on the septal branch. Septa1 ischemia could result in ventricular dysfunction or conduction abnormalities. The origin and course of the initial septal branch in this patient was not detected by echocardiography or by aortic root angiography with balloon occlusion using the laid-back projection. (AD = anterior descending coronary artery; Cx = circumflex artery; RCA = right coronary artery.)
nately, proximal coronary artery stenosis may be missed by an aortogram, and patients with coronary occlusion may be asymptomatic with normal resting electrocardiograms and echocardiograms after an arterial switch operation [8, 91. Thus, Asou and associates can only speculate that the intramural coronary arteries in their patients are currently patent and free of stenoses. Asou and associates strongly suggest that all coronary patterns are amenable to translocation with no difference in risk. However, even their expertise may be overstated. If only patients with d-transposition of the great arteries are considered in their series, risk of operative mortality for patients with a right coronary artery course anterior to the great arteries was low, but significantly greater than the risk of operative mortality for patients with the two most common coronary patterns (Fisher exact text, p = 0.049).
A collaborative study has identified coronary patterns that increase the risk of the arterial switch operation [l]. Thus, accurate preoperative and postoperative evaluations of coronary anatomy and perfusion may be of value in planning and interpreting the outcome of various surgical procedures for d-transposition of the great arteries (Fig 1).Coronary anatomy can be described accurately and safely by several echocardiographic and angiographic methods. In some institutions, the arterial switch operation is presently performed independent of the coronary anatomy. In other institutions, patients with unusual coronary patterns are palliated by balloon atrial septostomy and treated with an atrial switch operation later in infancy. An equivalent risk for neonatal and infant atrial switch operations has not been reported. A longterm, randomized, prospective study could test the hypothesis that the outcomes of arterial and atrial switch
EDITORIAL DAY INTRAMURAL CORONARY ARTERIES
Ann Thorac Surg 1994;57283-5
approaches are different for patients with unusual coronary patterns. However, individual institutions may not have sufficient patients to determine differences in outcome, and a multicenter study may be limited by institutional differences in the results of both arterial and atrial switch procedures. Thus, the long-term superiority of one technique may never be resolved for the subgroup of patients with unusual coronary patterns. Uniform guidelines have not been defined for the long-term follow-up of coronary perfusion in arterial switch patients. If follow-up evaluations are not performed and symptoms of coronary occlusion develop over a prolonged interval in some patients, we may fail to identify risk factors of potential value to future arterial switch candidates for several years. Many tests of coronary perfusion are somewhat invasive, costly, or of limited availability. However, the long-term effects of coronary reimplantation on vessel growth and myocardial perfusion are unknown. Thus, noninvasive evaluations of myocardial perfusion and function (at rest and with exertion or pharmacological stress), and a heart catheterization with coronary angiography may be justified in all patients 1 year after operation and during adolescence. Many talented surgeons are responsible for the encouraging early and intermediate results of the arterial switch operation. Ongoing studies may confirm that the longterm outcome of all patients with transposition can be improved as a result of their innovative efforts.
285
References 1. Kirklin JW, Blackstone EH, Tchervenkov CI, Castaneda AR.
Clinical outcomes after the arterial switch operation for transposition: patient, support, procedural, and institutional risk factors. Circulation 1992;86:1501-15. 2. Sim EKW, van Son JAM, Julsrud PR, Puga FJ. Aortic intramural course of the left coronary artery in dextro-transposition of the great arteries. Ann Thorac Surg 1994;57:458-60. 3. Asou T, Karl TR, Pawade A, Mee RBB. Arterial switch: translocation of the intramural coronary artery. Ann Thorac Surg 1994;57461-5. 4. Shaher RM, Puddu GC. Coronary arterial anatomy in complete transposition of the great arteries. Am J Cardiol 1966;17: 35541. 5. Gittenberger-de Groot AC, Sauer U, Quaegebeur J. Aortic intramural coronary artery in three hearts with transposition of the great arteries. J Thorac Cardiovasc Surg 1986;91:566-71. 6. Vlodaver Z, Neufeld HN, Edwards JE. Pathology of coronary disease. Semin Roentgen01 1972;7376-94. 7. Mustafa I, Gula G, Radley-Smith R, Durrer S, Yacoub M.
Anomalous origin of the left coronary from the anterior aortic sinus: a potential cause of sudden death. J Thorac Cardiovasc Surg 1981;82:297-300. 8. Wernovsky G, Hougen TJ, Walsh EP, et al. Midterm results after the arterial switch operation for transposition of the great arteries with intact ventricular septum: clinical, hemodynamic, echocardiographic, and electrophysiological data. Circulation 1988;77:133344. 9. Day RW, Laks H, Drinkwater DC. The influence of coronary anatomy on the arterial switch operation in neonates. J Thorac Cardiovasc Surg 1992;104:706-12.