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Intraoperative ultrasonographic identification of coronary artery compression after an arterial switch procedure
J
THORAC CARDIOVASC SURG
1991;102:837-40
Intraoperative ultrasonographic identification of coronary artery compression after an arterial switch procedure A case is reported of a neonate with transposition of the great arteries, undergoing an arterial switch operation, in whom the cause for postbypass cardiac failure was diagnosed by intraoperative epicardial echocardiography. Obvious regional dyskinesia was seen by two-dimensional echocardiography in the posterolateral segments of the left ventricle, supplied by the circumflex coronary artery. After the switch procedure, the reimplanted circumflex artery ran between the aorta and the pulmonary artery. Lifting the pulmonary artery off the circumflex artery resulted in immediate improvement of regional myocardial function, which could be monitored on-line with echocardiography. Thus compression of the circumflex by the pulmonary artery was the cause for cardiac failure. On the basis of the echocardiographic information, immediate and successful surgical revision was performed. Intraoperative epicardial echocardiography has a unique diagnostic potential in the case of cardiac failure after cardiopulmonary bypass.
Jan Quaegebeur, MD, Marc van Daele, MD, Oliver Stiimper, MD,* and George R. Sutherland, MD, FRCP, Rotterdam, The Netherlands
firing the past 10 years the neonatal arterial switch operation has found increasing favor as the therapy of choice for transposition of the great arteries (TGA). Current surgical results suggest that the mortality rate for such a procedure should be less than 5%.1-3 Although the variability in both the origin and branching pattern of the coronary arteries has proved not to be an incremental risk factor for death after such a procedure, failure to perfectly reestablish the coronary circulation will invariably result in disaster. Difficulties arising during or after coronary reimplantation are usually the result of a combination of anatomic factors rather than of the morphology of the coronary arteries per se. In general it is difficult for the surgeon to rapidly determine intraoperatively the cause of acute cardiac failure after a surgical procedure. Intraoperative epicardial echocardiography can now potentially provide the surgeon with a tool to check on both cardiac structure and function immediately after a repair. We wish to report the From Thoraxcenter, University Hospital Rotterdarn-Dijkzigt, Rotterdam, and Interuniversity Cardiology Institute of the Netherlands. Received for publication March 13, 1990. Accepted for publication Nov. 15, 1990. 'Supported by the Deutsche Forschungsgemeinschaft.
12/1/27992
case of a patient in whom the use of intraoperative echocardiography led to the correct diagnosis and the successful repair of extrinsic compression of a reimplanted coronary artery that was causing regional myocardial ischemia and resulting in acute left ventricular failure after an arterial switch operation.
Case report A girl weighing3.3 kg with simpletransposition of the great arteries underwent an arterial switchoperation at 8 days of age. The morphologic diagnosis was based solely on echocardiographic information. At operation the aorta was found to be slightly anterior to the pulmonary artery and deviated to the right.The left anterior descendingartery arose together with the right coronary artery from sinus I, whereas the circumflexcoronary artery arose from sinus 2 (I LR 2ex, Fig. I, a ).4 In addition, there was severe malalignment between the interostial commissures of the semilunar valves. The commissurebetween aortic sinuses I and 2 was opposed to the middle of the correspondingfacing sinus of the pulmonary valve.As a direct consequenceof this, two commissuresof the pulmonary valvewere situated exactlyat the theoretic implantation point of both coronaryarteries. However, this problem was easily circumvented by implanting both coronary arteries into the same sinus. The left anterior descending plus the right coronary artery were implanted into the left side of that sinus through a simple incision. The circumflex coronary artery was implanted into the right side of the same sinus by means of an incision and a flap technique from the transection site (Fig. I, b). After reimplan-
837
838
The .Journalcf Thoracic and Cardiovascular Surgery
Quaegebeur et al.
1a:
ex
,,,",+,.n Post
Ant
l b : Implantation technique:
tc : After Revision:
---J--+I,
_ _I
I I
I
Fig. 1. a, The anatomy and the spatial interrelationships of the semilunar valves,coronary arteries, and great arteries. b, The anatomy after the initial surgical procedure. The great vesselshave been switched. No Lecompte maneuver has been performed and the left pulmonary artery runs posterior to the aorta. Both coronary arteries have been reimplanted in the same sinus of the pulmonary (neoaortic) valve. The proximal part of the circumflex coronary artery is compressed between the aorta and the posteriorly directed pulmonary artery. c, Anatomy after surgical revision (Lecompte maneuver). The pulmonary artery now is directed anterior to the aorta and no longer compresses the circumflex coronary artery. RCA, Right coronary artery; Cx, circumflex; LAD, left anterior descending; Ao, aorta; PA, pulmonary artery; R, right; L, left; NF, nonfacing.
tation both coronary artery systems could easily be probed, and they presented a smooth course. Because the aorta lay very much to the right of the pulmonary artery, the new pulmonary artery was constructed without the use of a Lecompte maneuver. This meant that the bifurcation ofthe pulmonary artery was passed behind the reconstructed aorta and the direct anastomosis between the new pulmonary artery and its bifurcation was performed to the right of the aorta (Fig. I, b). After cardiopulmonary bypass had been discontinued, blood pressure remained low despite optimal preload conditions and the concomitant use of inotropic support (arterial pressure 38/30 mm Hg, left atrial mean pressure 7 mm Hg, inotropic support with dopamine 7 ltg/kg/min and nitroglycerin 3 ltg/kg/min. Routine epicardial echocardiography was carried out by
standard methods previously described." In both the long-axis view of the left ventricle and the short-axis view (the latter recorded at the levelof the papillary muscles), there was marked akinesia of the posterolateral left ventricular wall, whereas the contraction patterns in the anterolateral and septal areas were normal. Aortic incompetence was excluded by means of a combination of color flow mapping and pulsed Doppler interrogation, as was any gradient across either the left and right ventricular outflow tracts or across the anastomotic sites in the great vessels. With the left ventricular contraction pattern in the short-axis view being continuously monitored, the pulmonary artery was then lifted laterally away from the aorta with a forceps. This maneuver resulted in immediate normalization in the contraction pattern in the left ventricular posterolateral wall. Releasing the pulmonary artery back to its original position
Volume 102 Number 6 December 1991
Ultrasonography in arterial switch
839
c
Area ED 1.71 sqc~ Area ES 1.93 sqc~ Area EF 3'.LB1 %
Area ED 1.11 sqc~ Area ES 9.11 sqca Areil EF 71.37 %
Fig. 2. Schematic representation of the regional wall motion abnormalities that were observed by epicardial echocardiography after the initial surgical procedure. a, The orientation of the ventricles in the image when the transducer is placed on the anterior surface of the heart and a short-axis ventricular view is obtained. band C, Computer printouts, derived off-line from videotape, of the endocardial border of the left ventricle in a short-axis view at end-diastole (ED) and end-systole (ES). b, Before lifting the pulmonary artery anteriorly. c, After lifting the pulmonary artery for approximately 20 seconds. Segments 4, 5, and 6 represent the septum and areas 7 and 8 represent the posterolateral wall of the left ventricle (compare top panel). The position of the septum relative to the transducer hardly changes despite good function, since the transducer is placed directly on the right ventricle, which is contracting simultaneously with the left ventricle. Note the obvious difference in regional systolic shortening in the posterolateral area during compression versus decompression of the circumflex coronary artery. EF, Ejection fraction.
again immediately induced the sequence of hypokinesia, akinesia, and dyskinesia in the same segments within 15 seconds. This maneuver was subsequently repeated and the results were identical to those described earlier (Fig. 2). On the basis of this echocardiographic information, we concluded that the circumflex coronary artery was being compressed by the pulmonary artery. Cardiopulmonary bypass was immediately reestablished and the anastomoses of the aorta and pulmonary artery were taken down. A Lecompte maneuver was then performed and the aorta reconstructed. The coronary artery anastomoses were left as they were. Because the new pulmonary root was still too much to the right of the new aortic root, a pericardial patch enlargement was used to anastomose the left side of the bifurcation without any tension. The reconstruction of the pulmonary artery was concluded in the normal fashion. The infant could then be weaned from cardiopulmonary bypass without a problem, and a repeated cross-sectional echocardiographic examination demonstrated a normal contraction pattern in all left ventricular segments. Excellent left ventricular function was confirmed 24 hours postoperatively by
precordial echocardiography, with no evidence of any residual myocardial damage, and the infant was weaned from the respirator on the second postoperative day.
Discussion This case emphasizes how narrow the margin is between success and disaster when performing the arterial switch as a routine procedure for neonates with TGA. Although we continue to believe, with others," that in TGA the coronary anatomy as such does not increase the risk of operation (with some reservation for the intramural course of a proximal coronary artery"), we are also convinced that perfect coronary reimplantation remains the keystone for a successful arterial switch. Other factors than coronary morphology alone, however, may play an important role in the reconstitution of a normal coronary circulation.
The Journal of
8 4 0 Quaegebeur et al.
The type of coronary artery branching pattern present in this case (lRL 2ex) was identified in only 4% of 790 autopsy cases of TGA. 8 The fact that the commissure between the two aortic facing sinuses was opposed to the middle of the facing pulmonary sinus forced us to reimplant both coronary arteries in the same sinus. Although both anastomoses were technically perfect, the site of reimplantation of the circumflex lay more anteriorly than usual. A third complicating factor was the spatial relationship between the aorta and the pulmonary artery. Because of the nearly side-by-side position of the great arteries, a Lecompte maneuver was not initially performed and the new pulmonary artery with its left branch was passed to the right behind the reconstructed aorta. Subsequently, when the infant was being weaned from cardiopulmonary bypass (with no elevation of the postoperative pulmonary pressure and under normal loading conditions), the pulmonary artery was demonstrated to compress the circumflex coronary artery. Temporary elevation of the pulmonary vascular resistance can occur after neonatal cardiac surgery, and such an acute elevation of the pulmonary artery pressure could in theory produce acute dilatation of the pulmonary artery, which in turn could be responsible for coronary artery compression immediately after repair. Epicardial intraoperative cardiac ultrasonography with a combination of cross-sectional imaging, color flow mapping, and pulsed and continuous-wave Doppler studies has been routinely used in the surgery of congenital heart disease in our center since January 1988. This report again demonstrates the value of this technique as it precisely defined the immediate onset of regional left ventricular wall motion abnormalities immediately after a switch procedure. By using a combination of cross-sectional views to visualize left ventricular function, we could rapidly establish that it was the myocardial territory supplied by the circumflex coronary artery which was akinetic, and that extrinsic compression by the pulmonary artery was the only explanation for this. Decompressing the circumflex by elevating the pulmonary artery, while monitoring left ventricular function by ultrasonography in real time, confirmed that this indeed was the case. Thus the surgeon was able to diagnose the problem quickly and accurately before irreversible myocardial damage occurred.
Thoracic and Cardiovascular Surgery
In our experience, epicardial intraoperative ultrasonography immediately after surgical repair is also of value to eliminate other problems that can give rise to inadequate ventricular performance, such as semilunar valve incompetence, atrioventricular valve incompetence, residual ventricular septal defects, or stenosis of a ventricular outflow tract or an anastomotic site. In our center the application of such intraoperative ultrasonographic studies, integrated with the surgery of complex congenital heart disease, has so far resulted in immediate surgical revision in nine of 290 patients. This case is an excellent example of the unique role that such studies can play during both the intraoperative and immediate postoperative management of such complex cases.
I. 2.
3. 4.
5.
6. 7.
8.
REFERENCES QuaegebeurJH, Rohmer J, Ottenkamp J, et al. The arterial switchoperation: an eight-yearexperience. J THORAC CAR. DIOVASC SURG 1986;92:361-84. Trusler GA, Castaneda AR, Rosenthal A, et al. Current resultsof managementin transposition of the great arteries, with special emphasison patients with associated ventricular septal defect. J Am Coli CardioI1987;1O:1061-71. Castaneda AR, Trusler GA, Blackstone EH, et al. The early resultsof treatment of simpletransposition in the current era. J THORAC CARDIOVASC SURG 1988;95:14-28. Gittenberger-de Groot AC, Sauer U, Oppenheimer-Dekker A, Quaegebeur JM. Coronary arterial anatomy in transposition of the great arteries: a morphologic study. Pediatr Cardiol I983;4(suppl 1):15. Sutherland GR, Quaegebeur J, van Daele MERM, Stumper OFW, Hess J. Intraoperative echocardiography in congenital heart disease: an overview. In: Erbel et al., eds. Transesophageal echocardiography. Berlin: Springer Verlag, 1989:306-16. Yacoub MH. Anatomic correction of transposition of the great arteries: surgical technique. Pediatr Cardiol 1983; 4(suppl 1):61. Gittenberger-de Groot AC, Sauer U, QuaegebeurJM. Aortic intramural coronaryartery in three hearts with transposition of the great arteries. J THORAC CARDIOVASC SURG 1986;91 :566-71. QuaegebeurJM. Coronaryarterial anatomyin transposition ofthe great arteries:an anatomicaland clinical study.In:The arterial switch operation. Belgium: Rozengaard-Deerlijk, 1986;43-72.
THORAC CARDIOVASC SURG
1991;102:837-40
Intraoperative ultrasonographic identification of coronary artery compression after an arterial switch procedure A case is reported of a neonate with transposition of the great arteries, undergoing an arterial switch operation, in whom the cause for postbypass cardiac failure was diagnosed by intraoperative epicardial echocardiography. Obvious regional dyskinesia was seen by two-dimensional echocardiography in the posterolateral segments of the left ventricle, supplied by the circumflex coronary artery. After the switch procedure, the reimplanted circumflex artery ran between the aorta and the pulmonary artery. Lifting the pulmonary artery off the circumflex artery resulted in immediate improvement of regional myocardial function, which could be monitored on-line with echocardiography. Thus compression of the circumflex by the pulmonary artery was the cause for cardiac failure. On the basis of the echocardiographic information, immediate and successful surgical revision was performed. Intraoperative epicardial echocardiography has a unique diagnostic potential in the case of cardiac failure after cardiopulmonary bypass.
Jan Quaegebeur, MD, Marc van Daele, MD, Oliver Stiimper, MD,* and George R. Sutherland, MD, FRCP, Rotterdam, The Netherlands
firing the past 10 years the neonatal arterial switch operation has found increasing favor as the therapy of choice for transposition of the great arteries (TGA). Current surgical results suggest that the mortality rate for such a procedure should be less than 5%.1-3 Although the variability in both the origin and branching pattern of the coronary arteries has proved not to be an incremental risk factor for death after such a procedure, failure to perfectly reestablish the coronary circulation will invariably result in disaster. Difficulties arising during or after coronary reimplantation are usually the result of a combination of anatomic factors rather than of the morphology of the coronary arteries per se. In general it is difficult for the surgeon to rapidly determine intraoperatively the cause of acute cardiac failure after a surgical procedure. Intraoperative epicardial echocardiography can now potentially provide the surgeon with a tool to check on both cardiac structure and function immediately after a repair. We wish to report the From Thoraxcenter, University Hospital Rotterdarn-Dijkzigt, Rotterdam, and Interuniversity Cardiology Institute of the Netherlands. Received for publication March 13, 1990. Accepted for publication Nov. 15, 1990. 'Supported by the Deutsche Forschungsgemeinschaft.
12/1/27992
case of a patient in whom the use of intraoperative echocardiography led to the correct diagnosis and the successful repair of extrinsic compression of a reimplanted coronary artery that was causing regional myocardial ischemia and resulting in acute left ventricular failure after an arterial switch operation.
Case report A girl weighing3.3 kg with simpletransposition of the great arteries underwent an arterial switchoperation at 8 days of age. The morphologic diagnosis was based solely on echocardiographic information. At operation the aorta was found to be slightly anterior to the pulmonary artery and deviated to the right.The left anterior descendingartery arose together with the right coronary artery from sinus I, whereas the circumflexcoronary artery arose from sinus 2 (I LR 2ex, Fig. I, a ).4 In addition, there was severe malalignment between the interostial commissures of the semilunar valves. The commissurebetween aortic sinuses I and 2 was opposed to the middle of the correspondingfacing sinus of the pulmonary valve.As a direct consequenceof this, two commissuresof the pulmonary valvewere situated exactlyat the theoretic implantation point of both coronaryarteries. However, this problem was easily circumvented by implanting both coronary arteries into the same sinus. The left anterior descending plus the right coronary artery were implanted into the left side of that sinus through a simple incision. The circumflex coronary artery was implanted into the right side of the same sinus by means of an incision and a flap technique from the transection site (Fig. I, b). After reimplan-
837
838
The .Journalcf Thoracic and Cardiovascular Surgery
Quaegebeur et al.
1a:
ex
,,,",+,.n Post
Ant
l b : Implantation technique:
tc : After Revision:
---J--+I,
_ _I
I I
I
Fig. 1. a, The anatomy and the spatial interrelationships of the semilunar valves,coronary arteries, and great arteries. b, The anatomy after the initial surgical procedure. The great vesselshave been switched. No Lecompte maneuver has been performed and the left pulmonary artery runs posterior to the aorta. Both coronary arteries have been reimplanted in the same sinus of the pulmonary (neoaortic) valve. The proximal part of the circumflex coronary artery is compressed between the aorta and the posteriorly directed pulmonary artery. c, Anatomy after surgical revision (Lecompte maneuver). The pulmonary artery now is directed anterior to the aorta and no longer compresses the circumflex coronary artery. RCA, Right coronary artery; Cx, circumflex; LAD, left anterior descending; Ao, aorta; PA, pulmonary artery; R, right; L, left; NF, nonfacing.
tation both coronary artery systems could easily be probed, and they presented a smooth course. Because the aorta lay very much to the right of the pulmonary artery, the new pulmonary artery was constructed without the use of a Lecompte maneuver. This meant that the bifurcation ofthe pulmonary artery was passed behind the reconstructed aorta and the direct anastomosis between the new pulmonary artery and its bifurcation was performed to the right of the aorta (Fig. I, b). After cardiopulmonary bypass had been discontinued, blood pressure remained low despite optimal preload conditions and the concomitant use of inotropic support (arterial pressure 38/30 mm Hg, left atrial mean pressure 7 mm Hg, inotropic support with dopamine 7 ltg/kg/min and nitroglycerin 3 ltg/kg/min. Routine epicardial echocardiography was carried out by
standard methods previously described." In both the long-axis view of the left ventricle and the short-axis view (the latter recorded at the levelof the papillary muscles), there was marked akinesia of the posterolateral left ventricular wall, whereas the contraction patterns in the anterolateral and septal areas were normal. Aortic incompetence was excluded by means of a combination of color flow mapping and pulsed Doppler interrogation, as was any gradient across either the left and right ventricular outflow tracts or across the anastomotic sites in the great vessels. With the left ventricular contraction pattern in the short-axis view being continuously monitored, the pulmonary artery was then lifted laterally away from the aorta with a forceps. This maneuver resulted in immediate normalization in the contraction pattern in the left ventricular posterolateral wall. Releasing the pulmonary artery back to its original position
Volume 102 Number 6 December 1991
Ultrasonography in arterial switch
839
c
Area ED 1.71 sqc~ Area ES 1.93 sqc~ Area EF 3'.LB1 %
Area ED 1.11 sqc~ Area ES 9.11 sqca Areil EF 71.37 %
Fig. 2. Schematic representation of the regional wall motion abnormalities that were observed by epicardial echocardiography after the initial surgical procedure. a, The orientation of the ventricles in the image when the transducer is placed on the anterior surface of the heart and a short-axis ventricular view is obtained. band C, Computer printouts, derived off-line from videotape, of the endocardial border of the left ventricle in a short-axis view at end-diastole (ED) and end-systole (ES). b, Before lifting the pulmonary artery anteriorly. c, After lifting the pulmonary artery for approximately 20 seconds. Segments 4, 5, and 6 represent the septum and areas 7 and 8 represent the posterolateral wall of the left ventricle (compare top panel). The position of the septum relative to the transducer hardly changes despite good function, since the transducer is placed directly on the right ventricle, which is contracting simultaneously with the left ventricle. Note the obvious difference in regional systolic shortening in the posterolateral area during compression versus decompression of the circumflex coronary artery. EF, Ejection fraction.
again immediately induced the sequence of hypokinesia, akinesia, and dyskinesia in the same segments within 15 seconds. This maneuver was subsequently repeated and the results were identical to those described earlier (Fig. 2). On the basis of this echocardiographic information, we concluded that the circumflex coronary artery was being compressed by the pulmonary artery. Cardiopulmonary bypass was immediately reestablished and the anastomoses of the aorta and pulmonary artery were taken down. A Lecompte maneuver was then performed and the aorta reconstructed. The coronary artery anastomoses were left as they were. Because the new pulmonary root was still too much to the right of the new aortic root, a pericardial patch enlargement was used to anastomose the left side of the bifurcation without any tension. The reconstruction of the pulmonary artery was concluded in the normal fashion. The infant could then be weaned from cardiopulmonary bypass without a problem, and a repeated cross-sectional echocardiographic examination demonstrated a normal contraction pattern in all left ventricular segments. Excellent left ventricular function was confirmed 24 hours postoperatively by
precordial echocardiography, with no evidence of any residual myocardial damage, and the infant was weaned from the respirator on the second postoperative day.
Discussion This case emphasizes how narrow the margin is between success and disaster when performing the arterial switch as a routine procedure for neonates with TGA. Although we continue to believe, with others," that in TGA the coronary anatomy as such does not increase the risk of operation (with some reservation for the intramural course of a proximal coronary artery"), we are also convinced that perfect coronary reimplantation remains the keystone for a successful arterial switch. Other factors than coronary morphology alone, however, may play an important role in the reconstitution of a normal coronary circulation.
The Journal of
8 4 0 Quaegebeur et al.
The type of coronary artery branching pattern present in this case (lRL 2ex) was identified in only 4% of 790 autopsy cases of TGA. 8 The fact that the commissure between the two aortic facing sinuses was opposed to the middle of the facing pulmonary sinus forced us to reimplant both coronary arteries in the same sinus. Although both anastomoses were technically perfect, the site of reimplantation of the circumflex lay more anteriorly than usual. A third complicating factor was the spatial relationship between the aorta and the pulmonary artery. Because of the nearly side-by-side position of the great arteries, a Lecompte maneuver was not initially performed and the new pulmonary artery with its left branch was passed to the right behind the reconstructed aorta. Subsequently, when the infant was being weaned from cardiopulmonary bypass (with no elevation of the postoperative pulmonary pressure and under normal loading conditions), the pulmonary artery was demonstrated to compress the circumflex coronary artery. Temporary elevation of the pulmonary vascular resistance can occur after neonatal cardiac surgery, and such an acute elevation of the pulmonary artery pressure could in theory produce acute dilatation of the pulmonary artery, which in turn could be responsible for coronary artery compression immediately after repair. Epicardial intraoperative cardiac ultrasonography with a combination of cross-sectional imaging, color flow mapping, and pulsed and continuous-wave Doppler studies has been routinely used in the surgery of congenital heart disease in our center since January 1988. This report again demonstrates the value of this technique as it precisely defined the immediate onset of regional left ventricular wall motion abnormalities immediately after a switch procedure. By using a combination of cross-sectional views to visualize left ventricular function, we could rapidly establish that it was the myocardial territory supplied by the circumflex coronary artery which was akinetic, and that extrinsic compression by the pulmonary artery was the only explanation for this. Decompressing the circumflex by elevating the pulmonary artery, while monitoring left ventricular function by ultrasonography in real time, confirmed that this indeed was the case. Thus the surgeon was able to diagnose the problem quickly and accurately before irreversible myocardial damage occurred.
Thoracic and Cardiovascular Surgery
In our experience, epicardial intraoperative ultrasonography immediately after surgical repair is also of value to eliminate other problems that can give rise to inadequate ventricular performance, such as semilunar valve incompetence, atrioventricular valve incompetence, residual ventricular septal defects, or stenosis of a ventricular outflow tract or an anastomotic site. In our center the application of such intraoperative ultrasonographic studies, integrated with the surgery of complex congenital heart disease, has so far resulted in immediate surgical revision in nine of 290 patients. This case is an excellent example of the unique role that such studies can play during both the intraoperative and immediate postoperative management of such complex cases.
I. 2.
3. 4.
5.
6. 7.
8.
REFERENCES QuaegebeurJH, Rohmer J, Ottenkamp J, et al. The arterial switchoperation: an eight-yearexperience. J THORAC CAR. DIOVASC SURG 1986;92:361-84. Trusler GA, Castaneda AR, Rosenthal A, et al. Current resultsof managementin transposition of the great arteries, with special emphasison patients with associated ventricular septal defect. J Am Coli CardioI1987;1O:1061-71. Castaneda AR, Trusler GA, Blackstone EH, et al. The early resultsof treatment of simpletransposition in the current era. J THORAC CARDIOVASC SURG 1988;95:14-28. Gittenberger-de Groot AC, Sauer U, Oppenheimer-Dekker A, Quaegebeur JM. Coronary arterial anatomy in transposition of the great arteries: a morphologic study. Pediatr Cardiol I983;4(suppl 1):15. Sutherland GR, Quaegebeur J, van Daele MERM, Stumper OFW, Hess J. Intraoperative echocardiography in congenital heart disease: an overview. In: Erbel et al., eds. Transesophageal echocardiography. Berlin: Springer Verlag, 1989:306-16. Yacoub MH. Anatomic correction of transposition of the great arteries: surgical technique. Pediatr Cardiol 1983; 4(suppl 1):61. Gittenberger-de Groot AC, Sauer U, QuaegebeurJM. Aortic intramural coronaryartery in three hearts with transposition of the great arteries. J THORAC CARDIOVASC SURG 1986;91 :566-71. QuaegebeurJM. Coronaryarterial anatomyin transposition ofthe great arteries:an anatomicaland clinical study.In:The arterial switch operation. Belgium: Rozengaard-Deerlijk, 1986;43-72.