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Supravalvar aortic stenosis: unexpected findings at surgery
  1. C Grahame-Clarkea,
  2. W B Pugsleyb,
  3. R H Swantona
  1. aDepartment of Cardiology, The Middlesex Hospital, Mortimer Street, London W1N 8AA, UK, bHolmes-Sellors Cardiothoracic Unit, The Middlesex Hospital
  1. Dr C Grahame-Clarke, The Crucifom Project, The Institute of Neurology, 1 Wakefield Street, London WC1N 1PJ, UK.

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A 51 year old man was referred for investigation of presumed valvar aortic stenosis. A murmur had been noted as a child but he had developed normally and was entirely asymptomatic. He had had two episodes of infective endocarditis successfully treated medically in 1968 and 1977. He was currently on no medication. Annual echocardiography had shown a possible bicuspid aortic valve with a pressure gradient of 30 mm Hg and a hypertrophied left ventricle with good systolic function.

Examination revealed a fit man with a blood pressure of 140/90 mm Hg in the right arm but only 110 mm Hg systolic in the left, suggesting a preferential streaming up the innominate artery. His pulse was regular at 68 beats/min, which was slow rising in quality. His jugular venous pressure was low and his apex beat was not displaced. He had a long ejection systolic murmur heard all over the precordium radiating to the carotids with no ejection sound.

Electrocardiography showed sinus rhythm with T wave inversion inferolaterally indicative of left ventricular hypertrophy. Chest radiography showed a normal cardiothoracic ratio and aortic arch.

Cardiac catheterisation revealed typical pressure tracings of supravalvar aortic stenosis with a pressure gradient of 50 mm Hg (fig1). There were giant patent coronaries (fig 2), a dilated innominate artery, and a stenosis at the origin of the left common carotid artery. Right sided pressures were normal with no pulmonary artery aneurysms on pulmonary angiography.

Figure 1

Pressure tracings on pullback of a single lumen catheter from the left ventricle (LV) to the aorta (Ao) showing the supravalvar stenosis (SVS) of 50 mm Hg.

Figure 2

(A) Angiogram from this case and (B) diagrammatic summary of supravalvar aortic stenosis. Reproduced from Pocket Consultant to Cardiology, 2nd ed, 1989, with kind permission of Blackwell Science Ltd.

At surgery the aorta was found to be stenotic just above the coronary ostia, which were greatly enlarged. The aortic valve, although tricuspid in architecture, was friable and regurgitant. It was excised and replaced with a 25 mm St Jude’s prosthesis. The aortic root wall was unexpectedly rigid, being up to 0.5 cm thick, which caused problems when enlarging the aortic root. Three separate pieces of pericardium were used to construct a gusset, which enlarged the root orifice from 3 mm to 1 cm in diameter. The patient made a satisfactory recovery and was fit and well at one year follow up. Histology of the aortic wall showed medial necrosis with focal calcification and disruption of the elastic lamina in keeping with a diagnosis of atheroma.

Discussion

Our patient had no features of Williams’s syndrome (mental deficiency, dysmorphic facies, and idiopathic hypercalcaemia), which is known to be associated with supravalvar aortic stenosis. This form of isolated supravalvar aortic stenosis is well known and has previously followed up as valvar aortic stenosis.1 Multiplane transoesophageal echocardiography has advantages over transthoracic echocardiography and may have helped in our diagnosis.2Both isolated supravalvar aortic stenosis and Williams’s syndrome are caused by mutations involving the elastin gene on chromosome 7q11.23.3 Elastin is present in all arterial walls, therefore, it is not surprising that other arteries are affected, as in our case. Although stenoses of the great vessels are rare, dysplasia of the pulmonary, brachiocephalic, and coronary arteries have been reported and can lead to premature coronary artery disease and death even in children.4 Coronary disease is thought to be exacerbated by high pressure in the coronary arteries secondary to the stenosis. Associated aortic valve disease is strongly correlated to late death and need for reoperation.5 Therefore, both right and left sided catheterisation are advisable, and early surgical intervention thought appropriate even when the individual is asymptomatic as in our case. It should be remembered that the aortic wall may be thick and difficult to close with a pericardial gusset.

References

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