Eur J Cardiothorac Surg 2001;20:1252-1254
© 2001 Elsevier Science NL
Atrioventricular septal defect with ‘absent’ pulmonary valve in the setting of Down's syndrome: a rare association
A. Giambertia,b,
N.N. Kalisc,
Robert H. Andersona,b,
Marc R. de Levala,b
a Cardiothoracic Unit, Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK
b Institute of Child Health, University College London, London WC1N 1EH, UK
c Cardiac Centre, Bahrain Defence Force Hospital, Bahrain, Arabian Gulf
Received 7 May 2001;
received in revised form 20 August 2001;
accepted 26 September 2001.
Corresponding author. Tel.: +44-20-7404-4383; fax: +44-20-7831-4931
e-mail: delevm{at}gosh.nhs.uk
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Abstract
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We report a rare case of a 2-year-old boy with Down's syndrome, atrioventricular septal defect and so-called ‘absent pulmonary valve syndrome’. Diagnostic imaging also revealed the presence of an anomalous high origin of the right coronary artery from the ascending aorta. Surgical repair was successful.
Key Words: Down's syndrome • Trisomy 21 • Outflow tract malformation • Common atrioventricular junction
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1. Introduction
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Tetralogy of Fallot is the most frequent associated cardiac malformation in Down's syndrome with atrioventricular septal defect, and is present in about 8% of cases [1]. So-called ‘absent pulmonary valve syndrome’ is also seen most frequently with tetralogy of Fallot but, to the best of our knowledge, there are no reports in the literature of patients having this feature with atrioventricular septal defect. We report this particularly rare association, additionally complicated by an anomalous high origin of the right coronary artery from the ascending aorta.
1.1. Clinical summary
A 2-year-old boy with Down's syndrome was diagnosed non-invasively to have atrioventricular septal defect, tetralogy of Fallot and ‘absent pulmonary valve syndrome’. Cross-sectional echocardiography in our centre confirmed the presence of an atrioventricular septal defect, with both infundibular and valvar obstruction to the right ventricular outflow tract. The right pulmonary artery and pulmonary trunk were dilated, but the left pulmonary artery was not seen. Cardiac catheterisation confirmed the absence of the leaflets of the pulmonary valve, along with the other findings, but showed the left pulmonary artery to be small, and revealed an unusually high origin of the right coronary artery.
We proceeded to surgical correction through a median sternotomy. Opening the right ventricular outflow tract revealed rudimentary formation of the leaflets of the pulmonary valve. There was gross dilatation of the right pulmonary artery, but the left pulmonary artery was less dilated. The right coronary artery arose above the sinu-tubular junction and ran vertically between the aorta and the pulmonary trunk (see Fig. 1)
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Cardiopulmonary bypass was initiated, and the patient was cooled to 22°C. The aorta was cross-clamped for 75 min with cold cardioplegic solution infused three times, and additional topical cooling. The right atrium was opened and the intracardiac anatomy assessed. A common atrioventricular junction was guarded by a common valve, with an infundibular extension of the large ventricular component of the atrioventricular septal defect. The antero–superior bridging leaflet was free-floating, the so-called ‘type C’ on the Rastelli classification. A vertical incision in the right ventricular outflow tract permitted resection of the infundibular stenosis. The dilated pulmonary trunk was transected and its two branches were fully mobilised. We did not plicate the right pulmonary artery, since it did not seem to be compressing the airways. A tear-shaped heterologous pericardial patch was used to close the ventricular component of the septal defect.
The zone of apposition between the left ventricular components of the bridging leaflets was closed with three sutures and, when the valve was tested, it was competent. An autologous pericardial patch was utilised to close the atrial component of the defect, leaving the coronary sinus on the left side. Having unclamped the aorta and rewarmed the patient, the right atrium was closed and a fresh antibiotic-preserved aortic homograft was sewn end-to-end to the pulmonary arteries and then to the right ventricular outflow tract. Cardiopulmonary bypass was discontinued after full rewarming, haemofiltration was undertaken, the cannulas removed, and the chest was closed routinely.
In the early post-operative period, the patient required a moderate amount of inotropic support, which was reduced within 48 h. On the third post-operative day the patient was extubated. Ten hours after extubation his condition deteriorated acutely. He was reintubated and the heart massaged, but spontaneous activity reappeared only after the sternotomy was reopened. It seemed that the homograft was compressing the anomalous origin of the right coronary artery. The haemodynamics slowly improved and it proved possible to close the chest one week after the incident, when the patient could again be weaned off inotropic support and ventilation.
We speculate that the desaturation in the hours which followed the extubation due to typical bronchial secretion in Down's syndrome increased the pulmonary vascular resistance and the pulmonary arterial pressure. With the increase in pressure, we presume that the homograft compressed the anomalous right coronary artery, producing myocardial ischaemia and triggering the cardiac arrest.
Since the second extubation, nonetheless, the patient has been stable haemodynamically, and has made very significant progress. He was discharged 51 days after the operation.
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2. Discussion
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Congenital cardiac defects are found in roughly half the children with Down's syndrome, atrioventricular septal defect with common valve being the most characteristic [1]. Except for some rare cases of double outlet right ventricle [2], the malformation typically involving the right ventricular outlets in this setting is tetralogy of Fallot [1]. Other cardiac malformations, such as pulmonary atresia, discontinuity of the pulmonary arteries, or so-called ‘absent pulmonary valve syndrome’, lesions typically observed in association with tetralogy of Fallot in patients with normal chromosomal patterns, or in patients with deletion of chromosome 22, are exceptionally rare when tetralogy of Fallot is found in patients with trisomy 21 [1,2]. Thus, our patient is the first that we have encountered with this combination of lesions. To our knowledge, there are no reports in the literature of patients having this particular association, nor has ‘absent’ pulmonary valve been seen with Down's syndrome [3].
The anatomic data required for pre-operative evaluation of patients with atrioventricular septal defect and/or ‘absent pulmonary valve syndrome’ may be confidently obtained by echocardiography [4,5]. In our case, the dilation of the right pulmonary artery and trunk was highly suggestive of ‘absent pulmonary valve syndrome’, but the inability to see the left pulmonary artery at the cross-sectional pre-operative echocardiography, and the rarity of the association, prompted cardiac catheterisation. Angiocardiography confirmed our suspicions, and showed the left pulmonary artery to be of normal calibre, a finding we cannot explain. Angiography also revealed the abnormally high take-off of the right coronary artery from the ascending aorta. This anomaly contributed to the difficult post-operative course, and its previous diagnosis proved significant in ensuring a successful outcome.
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Acknowledgments
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We thank Professor John Deanfield for the aortogram, and Dr Massimo Griselli for his help with the preparation of the manuscript and the bibliography research. Robert H. Anderson is supported by the British Heart Foundation together with the Joseph Levy Foundation. Research at the Institute of Child Health and Great Ormond Street Hospital for Children NHS Trust benefits from Research and Development funding received from the NHS Executive.
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References
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Abstract
1. Introduction
