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Eur J Cardiothorac Surg 2000;18:207-213
© 2000 Elsevier Science NL
Children's Heart Centre, University Medical Centre, Utrecht, The Netherlands
Received 6 September 1999; received in revised form 7 April 2000; accepted 16 May 2000.
Corresponding author. Department of Paediatric Cardiology, P.O. Box 85090, 3508 AB Utrecht, The Netherlands. Tel.: +31-30-250-4002
e-mail: p.hutter{at}wkz.azu.nl
| Abstract |
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Key Words: Congenital heart surgery Arterial switch operation Coronary anatomy Long-term outcome
| 1. Introduction |
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| 2. Methods |
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2.1. Statistical analysis
Analysis, using all subgroups of coronary anatomy, was impossible because of the small number of patients in each group except for the most common anatomy. Analysis was repeated using two groups (common vs. other). Chi-square analysis was used for ordinal data and Student's t-test for continuous variables. Multivariate analysis was performed using logistic regression.
| 3. Results |
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The coronary artery anatomy is described in Table 1. Single right ostium was encountered in three patients, in one of whom the left coronary looped around the pulmonary artery and in the other two ran between the great arteries. One additional patient had double outlet right ventricle with transposition and coarctation. He had a single coronary ostium from the right cusp, with the left coronary coursing between the great arteries before dividing in LAD and circumflex branches. It was deemed impossible to transfer the coronary. The coarctation was repaired and the pulmonary artery was banded with a view to later Rastelli operation. This is the first patient in our experience deemed un-switchable due to coronary anatomy. Since no arterial switch was performed, this patient is not included in the study.
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2=0.256, P=0.61). This was true regardless of the classification system used to describe coronary anatomy. Two patients died late. One patient died of pulmonary vascular occlusive disease. The other patient is described below.
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Two patients had an occluded left ostium with immediate post-operative ischaemia/infarction. Both had the most usual coronary anatomy. On follow-up, they had polymorphic ventricular extrasystoles and impaired LV function. Technetium scintigraphy demonstrated large irreversible defects in the left ventricle, and 12-lead and 24-h ECG showed polymorphic ventricular extra systoles. The left coronary ostium was completely occluded with the right coronary arising from the right cusp. There was collateral perfusion of the left coronary artery system (Fig. 1) . Both patients were asymptomatic with good exercise tolerance. However, they both developed ventricular fibrillation at the age of 14 years. One was successfully resuscitated and a defibrillator was implanted. This patient continues to do well. The defibrillator terminated one episode of ventricular fibrillation during strenuous exercise. At the time, we discussed an operation to re-perfuse the coronary, but this was declined, as the remaining left coronary was tiny. The events, of this patient, prompted further investigations in the second patient with occluded left coronary. An operation to re-perfuse the coronary was discussed but was declined, at the time, because there was no area of reversible ischaemia around the infarct. Implantation of a defibrillator was discussed, however, the parents refused based on the fact that the patient had no symptoms and on their religious background. The patient arrested on her way to the library. She was resuscitated but brain death was diagnosed upon her arrival in the hospital.
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Asymptomatic stenosis of the right coronary ostium was documented in one patient (Fig. 2) . Another patient has multiple tortuous collaterals without evident coronary obstructions (Fig. 3) . Both patients had the most frequent anatomy. They have normal ECG, normal left ventricular function, and normal scintigrams.
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Five patients had impaired LV function on echocardiography, confirmed by angiography. Coronary anatomy was 1Cx:2R,LAD in one patient and 1LAD,Cx:2R in four. Two, of these patients, were the patients with occluded left ostium. No coronary abnormalities were found in the remaining three patients. The left ventricular dysfunction was preceded by peri-operative ischaemia suggesting failure of myocardial protection. Two patients had normal ECG and normal scintigraphy. Both are asymptomatic with moderate LV dysfunction. The third patient developed myocardial dysfunction and secondary aortic insufficiency. A Ross-like procedure was performed placing the original aortic valve in the neo-aortic root [9]. After a brief initial improvement, recurrent aortic insufficiency was caused by dilation of the new aortic root. The aortic valve was replaced using a St Jude (18 mm) prosthesis. The left ventricle remains severely dilated and exercise tolerance is limited.
| 4. Discussion |
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The overall early and late mortality was 16%. This includes the initial learning curve when the arterial switch was still very much uncharted territory. The current (19962000) operative mortality is 2%. Although no relationship was found between anatomy and risk of peri-operative mortality, there are some forms of coronary anatomy that are generally recognized as more difficult, such as, intramural coronary artery. If recognized timely, this anatomy could be dealt with successfully. Patients with single right coronary ostium, with interarterial course of the left coronary can pose insurmountable problems. In our series, one patient was switched successfully, one patient died and one patient was not switched.
The study, by Bonhoeffer [4,5], includes a number of patients in whom a one-patch coronary transfer technique was used. This technique was never used in our institution. However, a similar number of late coronary sequellae was encountered (5/55). In two of these five patients the findings were completely unexpected, very similar to the 3% reported by Tanel [15].
Patients with coronary stenosis or occlusion can be asymptomatic and have normal ECG and Echo findings as demonstrated in two patients. The patient, with the occluded right coronary, currently has a normal 24-h ECG while the obstruction is still present. Scintigraphy as a method of screening for coronary obstructions is not very helpful, in our experience, as three of five patients with coronary sequellae had normal findings. Scintigraphy detects ischaemia and excellent collateral coronary circulation prevents ischaemia even during chemical stress. The same is expected to be true for stress-echocardiography and PET scanning, though we have no personal experience with these methods in transposition patients.
Coronary angiography is, therefore, the only tool to detect these silent obstructions. A therapeutic strategy dealing with obstructions still needs to be developed. An area with reversible ischaemia on stress-scintigraphy might provide an arrhythmogenic focus and an attempt should be made to re-perfuse the coronary by opening the obstructed ostium or performing some kind of bypass surgery. At the time, there was doubt if this would be beneficial in the surviving patient with left coronary obstruction. Currently the discussion regarding this patient is reopened as we have received various comments strongly advising that an attempt should be made.
In absence of reversibility, the benefits of re-operation may not outweigh the risks. If scintigraphy is normal the decision is difficult. If re-perfusion is easily and permanently achieved, such as in the patient with stenosis of the right ostium, we feel that it should be done. It is difficult to judge the risks and benefits in the asymptomatic patient with obstructed right coronary since she had already three repeat surgeries for pulmonary stenosis. The coronary is occluded over a distance of several centimeters and the only option seems to be some form of bypass. This, in essence, provides extra collateral circulation to the coronary with may impede the development of the collaterals that are currently providing adequate circulation even during exercise and chemical stress. The debate will continue until the collective experience increases and provides a more definite answer. Only very long-term studies can clarify the influence of ageing in these patients.
Finally, there is a small group of patients with postoperative ischaemia and normal coronary perfusion. This suggests failure of myocardial protection, which led to dilatation and secondary aortic insufficiency in one of these patients. The patient, 2 years old at the time, needed aortic valve replacement and a Ross-like procedure seemed to be the best choice, incidentally placing the original aortic valve in the neo-aortic root. The result was dilatation and subsequent recurrence of regurgitation.
In conclusion, abnormal coronary anatomy was not a statistically significant determinant of mortality in our study. However the study is limited in numbers and follow-up duration. Incidental patients with coronary anatomy that are very difficult or even impossible to transfer occur, but mortality can be avoided in experienced hands. Surgical coronary obstruction is independent of original anatomy. It can be almost silent and is potentially fatal. Follow-up coronary angiography is strongly advised although it carries a certain risk.
| Footnotes |
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| Appendix A Conference discussion |
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Now, my second question is that we have already identified those patients that you named type C in your classification, namely, patients who have the right coronary coming from the anterior descending with side-by side vessels, the anterior button after relocation can be compressed by the pulmonary artery. This has been corrected by lining up on the right the pulmonary trunk, but this has been, in our experience, a difficult problem. So my question is, have you selected your patients and do you really believe that type C is not statistically significant in your experience?
Dr Bennink: Well, I am not so long in paediatric heart surgery as you are, but my colleague, Professor Hitchcock, is, and it is not a selection, and we did not meet any intramural coronary anatomies until recently when we moved to the new hospital, and in the last eight switches we did, I had two switches with intramural anatomy, and both did very well, luckily, but they are not included in this study. So it is not a selection, and it is pure coincidence.
Dr A. Urban (St. Augustin, Germany): My question to you is a little similar to Francois Lacour-Gayet's question. Normally the distribution of coronary arteries in transposition is such that 63% are Type I, but you had about 82 or so percent of Type I. The other, more difficult types are less common but still they are very much less common in your series. So, again, the question, why is that?
One of your conclusions is that coronary anatomy has no impact on early and late outcome. You did not tell us about early outcome. We do not know your early mortality, and I think only if we know that we can follow your conclusion. And from our personal series of 364 arterial switch operations we are aware that if you have to relocate intramural coronary arteries, the mortality is higher. Intramural course of coronary arteries e.g. has a significant impact on early and late outcome. So I do not agree with your conclusion.
Dr Bennink: Well, I only can say that recently we did two intramurals and the early outcome was good, so they were both discharged after 10 or 12 days, if I remember correctly. What you do see is that there was no selection in this series, and I don't know why we have this distribution of coronary anatomy. And if I read the literature, I also thought that there is definitely an impact on early and late outcome depending on coronary pattern, but if you look at the numbers, they are relatively small in comparison with a big series. Of course if you look at it, I think it was in 1990, Wernovsky (Circulation) wrote a big series, and there, the coronary pattern did not have an impact on the outcome mortality but mainly on the morbidity.
Our early mortality, I quickly mentioned that out of the last 50 switches, we lost one, and before that 25 patients were lost in the whole series, but that includes the early days since 1977 with the two-stage repair. So our early mortality now is 2%.
Dr P. Pohlner (Brisbane, Australia): I was very interested in what you are able to do with the coronaries once you have defined that they are of no value. I think our experience has been, and most of the patients in fact have come from other centres, we don't see much of this problem in our institution, but we do have problems revascularizing these patients long term, and I just wonder what your experience and perhaps others has been about that. We do find, again, a range of abnormalities of single coronary arteries, intramural coronaries in addition to the ones you have already described. They are very difficult.
We have to use a variety of strategies to establish a good coronary position with switching. Our results are really very good and equivalent to your last stated results. But I do have some uncertainty about what we can do about the coronaries which do not remain patent.
Dr Bennink: I think it is a very good question. We are dealing with the same problem. I hope someone can give the answer, but we are not sure what to do especially with asymptomatic patients with no reversible defects in certain areas. There is no reason to do a bypass, for example.
We discussed this 14-year-old patient, and we thought that because he had a lot of ventricular extra systoles that he was best off by using an AICD. Of course we also were thinking about doing a bypass, but since the experience in that area is very limited, and there were irreversible defects, we decided to go the easier way of implanting an AICD. One of our reasons for presenting the problem of occluded coronaries is to discuss what to do with all those patients.
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