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Eur J Cardiothorac Surg 2007;31:894-898. doi:10.1016/j.ejcts.2007.02.003
Copyright © 2007, European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved
a Department of Pediatric Cardiac Surgery, University Paris Descartes and Sick Children Hospital, Paris, France
b Department of Pediatric Cardiology, University Paris Descartes and Sick Children Hospital, Paris, France
Received 19 December 2006; received in revised form 1 February 2007; accepted 2 February 2007.
* Corresponding author. Address: Pediatric Cardiac Surgery, Sick Children Hospital, 149 rue de Sèvres, 75015 Paris, France. Tel.: +33 1 44 38 18 67; fax: +33 1 44 38 19 11. (Email: pascal.vouhe{at}nck.aphp.fr).
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Abstract |
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 Top Abstract 1. Introduction2. Materials and methods3. Results4. Discussion5. ConclusionsReferences |
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Key Words: Arterial switch operation • Coronary lesions • Surgical revascularization
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1. Introduction |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. ConclusionsReferences |
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The incidence, pathophysiology, and treatment of coronary lesions remain matters of debate [1–4]. Therapeutic options include medical management, percutaneous transluminal dilation [5,6], and surgical revascularization [7,8].
To date, it has been our policy to perform surgical coronary revascularization in patients with coronary obstruction and evidence of myocardial ischemia. The present study was undertaken to evaluate the results of this approach.
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2. Materials and methods |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. ConclusionsReferences |
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The coronary anatomy distribution in the survivors was the following: usual coronary anatomy in 453 (63%), coronary patterns with anterior and/or posterior loops in 224 (31%), and coronary arteries coursing between the great arteries (with or without intramural course) in 36 (6%).
Among the 713 late survivors, 290 patients (41%) underwent at least one selective coronary angiography. Coronary angiography was performed for one of the following reasons: (1) electrocardiographic and/or echocardiographic findings suggestive of myocardial infarction or myocardial ischemia, (2) unusual coronary pattern potentially associated with a higher risk of coronary complications (coronary arteries coursing between the great arteries, with or without intramural course), (3) intraoperative difficulties in coronary transfer (particularly when coronary anastomosis revision was necessary), (4) systematic evaluation of patients who underwent coronary reimplantation using a single orifice technique [9], and (5) routine postoperative evaluation of coronary patency in ASO patients.
Coronary lesions were detected in 34 patients (12% of all patients undergoing coronary angiography, 5% of all late survivors). Surgical revascularization was not indicated in 15 patients, either because this was deemed technically impossible (2 patients) or because there was no evidence of myocardial ischemia at myocardial perfusion imaging (13 patients).
The remaining 19 patients who underwent surgery for coronary revascularization constitute the study group. This study was approved by the local ethics committee.
2.2 Study population (19 patients)
2.2.1 Arterial switch procedure
There were 14 boys and 5 girls. Mean age at operation was 9 ± 5 days (range 3–23 days). Twelve neonates had TGA with an intact ventricular septum (one of them had associated aortic coarctation) and seven had TGA with ventricular septal defect (VSD) (three with associated aortic coarctation). Eleven patients had usual coronary anatomy; four had coronary patterns with anterior and/or posterior loops, and four had coronary arteries coursing between the great arteries with an intramural coronary branch (left main in one and left anterior descending in three).
Coronary transfer was performed using standard techniques in 14 cases and using a single orifice technique in 5 cases [9]. The side-by-side reimplantation technique was associated with an unacceptably high incidence of coronary lesions and its use must be strongly discouraged [10]. In addition to ASO, seven patients underwent VSD closure and five had aortic coarctation repair.
All patients had an unremarkable early postoperative course and were discharged from hospital with normal electrocardiographic and echocardiographic evaluation.
2.2.2 Diagnosis of coronary lesions
Coronary lesions were detected after a mean interval of 33 ± 38 months (range 1 month–10 years) following ASO. One patient sustained a myocardial infarction with severe left ventricular dysfunction 1 month post-ASO. In seven patients, echocardiographic findings suggestive of myocardial ischemia developed several weeks after ASO (hyperechogenicity of a papillary muscle of the mitral valve with or without mitral insufficiency); all had normal global left ventricular function. In the last 11 patients, coronary lesions were detected at the time of routine coronary angiography, with normal electrocardiographic and echocardiographic findings.
Coronary lesions involved the left main coronary artery in 14 cases (9 stenoses and 5 occlusions), the left anterior descending artery in 3 cases (3 occlusions), and the right coronary artery in 2 cases (1 stenosis and 1 occlusion). Details regarding coronary lesions according to coronary anatomy are given in Table 1 .
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2.2.3 Surgical revascularization
Surgery was undertaken after a mean interval of 32 ± 34 months (range 15 days–8.4 years) following the diagnosis of coronary obstruction. Surgery was delayed in many patients as long as there was no clear evidence of myocardial ischemia. At the time of operation, mean age was 5.6 ± 3.2 years (range 3 months–10.5 years).
Most patients (16/19) underwent coronary angioplasty. Our technique has been reported elsewhere [7]. After median resternotomy and institution of cardiopulmonary bypass, the aorta was cross-clamped and cardioplegic solution was administered. The neopulmonary trunk was transected and both pulmonary stumps were freed from surrounding structures, thus exposing the aortic root and the coronary neo-ostia. The aorta was opened anteriorly and the incision was extended toward the involved coronary ostium. In stenotic lesions, the incision was extended across the stenotic area until a normal coronary arterial wall was reached; in atretic lesions, the coronary trunk beyond the obstruction was opened and both aortic and coronary incisions were joined together across the occluded area. An onlay patch was used to enlarge not only the coronary stem but also the aortic incision in order to give the new coronary ostium a funnel shape. A saphenous vein patch was used in 15 patients and an innominate vein patch in the last patient.
In two patients, the right coronary artery (arising from the left-sided ostium in one) was enlarged. In three patients, the left anterior descending artery was repaired. In the remaining 11 patients, the coronary angioplasty involved the left main coronary artery (arising from the right-sided ostium in 2 cases); in 4 of these patients, the incision was extended across the left main stem onto the origin of the left anterior descending artery.
One patient with a long atretic segment of the left main stem underwent implantation of a short saphenous vein bypass between the ascending aorta and the distal left main coronary artery, the distal anatomosis involving the origin of the left anterior descending artery.
Two patients had a mammary bypass using the left mammary artery; in one with occlusion of the left main stem, the bypass was implanted in a standard fashion on the left anterior descending artery; in the other patient with occlusion of an isolated left anterior descending artery, the artery was transected and anastomosed end-to-end to the mammary artery.
In addition to coronary revascularization, one patient underwent aortic arch repair for aortic recoarctation.
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3. Results |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. ConclusionsReferences |
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3.2 Late results
3.2.1 Follow-up
Mean follow-up was 6.3 ± 2.8 years (range 1–11 years). No patient was lost to follow-up. Evaluation was performed on a yearly basis.
3.2.2 Evaluation of coronary patency
The adequacy of coronary repair was evaluated in all patients. Most patients (17/19) underwent conventional coronary angiography; a total of 24 angiographic studies was performed after a mean follow-up of 2.5 ± 3.0 years.
In addition to coronarography, nine of these patients had coronary evaluation using multislice computed tomographic (MSCT) angiography. In the last two patients, coronary repair was evaluated using MSCT angiography alone.
All patients, except one, had a satisfactory angiographic result (provided by conventional and/or MSCT angiography). The two mammary bypasses (Fig. 1 ) and the saphenous vein bypass (Fig. 2 ) were patent. Fifteen of the 16 coronary angioplasties provided a satisfactory angiographic result (Fig. 3 ).
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In one patient (with myocardial infarction), there was a persistent perfusion defect in the infarcted area but the lateral perfusion defect had disappeared. In another patient (who underwent a mammary bypass) there was a limited apical perfusion defect 8 years postoperatively, whereas there was a large anterior defect before revascularization. The remaining 16 patients had normal myocardial perfusion during exercise or after injection of dipyridamole.
3.2.4 Echocardiographic evaluation
One patient had segmental left ventricular dysfunction related to myocardial infarction. In all the other patients, left ventricular function was normal. In three patients, there was hyperechogenicity of one mitral papillary muscle, with minimal mitral regurgitation in one. All residual echocardiographic lesions were present before revascularization.
3.2.5 Clinical status
All patients were leading a fully active, symptom-free life and did not receive cardiac medication, except long-term therapy with aspirin.
A treadmill exercise testing, performed in 11 patients after a mean follow-up of 6.0 ± 2.5 years, showed a normal effort tolerance without evidence of myocardial ischemia.
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4. Discussion |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. ConclusionsReferences |
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Major defect in coronary transfer leads to acute coronary ischemia and, in most cases, results in early death or myocardial infarction. Refinements in surgical techniques have progressively decreased the incidence of major defects in coronary transfer, even in neonates with unusual coronary patterns.
On the long term, the success of ASO may well depend on the continued patency and adequate functioning of the coronary arteries. It has been shown that the hazard function for coronary events shows a bimodal pattern with a rapidly declining early phase and a slowly increasing late phase [3]. If the causes of early events are clearly related to surgical failures, the pathophysiology of late events has not been completely elucidated. It has been postulated that reimplantation of the coronary arteries may produce subtle abnormalities which are not severe enough to yield to coronary ischemia but may cause proximal flow disturbances. Flow anomalies may, in turn, alter shear stress and induce progressive intimal thickening. Intracoronary ultrasound assessment late after ASO has revealed proximal eccentric intimal thickening in most (89%) coronary arteries. A total of 30% of arteries had significant proliferative lesions [4]. Progressive intimal proliferation may finally lead to severe coronary obstruction or even complete occlusion [11]. It must be pointed out that late coronary lesions may occur in all patients, even after the most straightforward initial operation and postoperative course.
The exact incidence of coronary lesions following ASO is difficult to evaluate because most patients with coronary obstruction are symptom-free and do not show any electrocardiographic or echocardiographic evidence of myocardial ischemia. Only systematic coronary angiography can detect such lesions. It has recently been shown that multislice computed tomographic angiography may replace conventional coronary angiography [12].
Our current policy is to perform coronary exploration (by coronary angiography and/or MSCT angiography): (1) early in the presence of any echocardiographic finding, even minimal, suggestive of myocardial ischemia, (2) during the first postoperative year in patients with unusual coronary patterns or intraoperative difficulties in coronary transfer, and (3) routinely before 5 years of age. Because the lesions are most probably progressive, coronary evaluation should be repeated at regular intervals during the late follow-up of ASO patients.
The optimal management of post-ASO coronary lesions remains to be determined. There are only a few reports dealing with this difficult problem. Recently, percutaneous transluminal coronary angioplasty has been shown to provide satisfactory mid-term results [6]. Potential surgical approaches include internal mammary artery grafting and coronary angioplasty. Internal thoracic artery–coronary artery bypass is technically feasible in most children and provides satisfactory patency rates for various indications in infancy and childhood [13]. However, the blood flow through a mammary bypass may be inadequate, particularly when a large myocardial area must be revascularized. Surgical coronary angioplasty has been used for atherosclerotic [14] as well as non-atherosclerotic lesions [7,15].
Surgical angioplasty restores a normal physiologic coronary perfusion and is likely to better preserve the future of the patients. Various materials can be used to achieve adequate revascularization: autologous pericardium, native aorta or pulmonary artery, internal thoracic artery, and saphenous vein. The optimal material for the long term remains to be determined.
The results of the present study show that coronary angioplasty can be performed in most children with post-ASO coronary lesions. The coronary obstruction (even when it is complete) is usually proximal and short and the coronary artery distal to the lesion is normal. It is, therefore, possible to achieve adequate enlargement from the aorta, across the stenotic or occlusive lesion, down to a normal coronary artery. The use of mammary grafting should be reserved to long and complete occlusion or to residual distal obstruction after primary coronary angioplasty (as it was the case in one of our patients).
Our date shows that (1) coronary angioplasty can be performed with a very low operative risk and a high patency rate and (2) successful revascularization restores normal myocardial perfusion in most cases, as assessed by myocardial perfusion imaging. The long-term fate of this procedure remains to be evaluated. The potential risks of progressive narrowing distal to the patch or modification of the patch material (aneurysmal dilation and/or progressive intimal thickening) should not be underestimated.
To date, revascularization has been carried out only in patients in whom myocardial ischemia at rest or under stress (or dipyridamole infusion) could be demonstrated. In many patients, surgery was even delayed for several months or years after the diagnosis of coronary obstruction, until frank ischemia could be shown. Owing to satisfactory results, our current policy is to propose surgery as soon as the diagnosis of coronary lesion with myocardial ischemia is performed. Revascularization should probably also be considered in the absence of obvious ischemia in order to restore normal coronary anatomy and perfusion, particularly in patients with coronary lesions and poor intercoronary collateral circulation.
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5. Conclusions |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. ConclusionsReferences |
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Acknowledgments |
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References |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. ConclusionsReferences |
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This article has been cited by other articles:
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  E. Bergoend, O. Raisky, A. Degandt, D. Tamisier, D. Sidi, and P. Vouhe Myocardial revascularization in infants and children by means of coronary artery proximal patch arterioplasty or bypass grafting: a single-institution experience. J. Thorac. Cardiovasc. Surg., August 1, 2008; 136(2): 298 - 305. [Abstract] [Full Text] [PDF]
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 E. Angeli, O. Raisky, D. Bonnet, D. Sidi, and P. R. Vouhe Late reoperations after neonatal arterial switch operation for transposition of the great arteries. Eur. J. Cardiothorac. Surg., July 1, 2008; 34(1): 32 - 36. [Abstract] [Full Text] [PDF]
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