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The arterial lesions of William’s syndrome are characteristic1: supravalvar aortic stenosis, coarctation of the aorta, peripheral pulmonary artery stenosis, and stenosis of the renal and coronary arteries. The development of slowly progressive coarctation has been described in only one patient,2 3 in whom angiography at 3 years of age showed a diffusely hypoplastic ascending aorta but no coarctation. Seven years later, angiography showed long segment coarctation distal to the left subclavian artery. We describe a patient in whom coarctation of the aorta developed over a much shorter time period.
William’s syndrome was diagnosed in this boy at the age of 4 years on the basis of “elfin facies” comprising epicanthic folds, a shallow nasal bridge, anteverted nares, long philtrum, and prominent lips.4 Hypercalcaemia had been noted during infancy. At routine follow up aged 5 years his femoral pulses were weak, with normal upper limb pulses. Echocardiography showed supravalvar aortic stenosis but no discrete coarctation; however, in view of the compelling clinical signs, cardiac catheterisation was performed in April 1993. There was no demonstrable gradient between the ascending and descending aorta. Aortic angiography showed no coarctation, although the descending aorta was diffusely hypoplastic (fig 1). The narrowest luminal point distal to the left subclavian artery measured 6.1 mm compared to the widest diameter of 8.3 mm.
In December 1996, clinical review again revealed weak femoral pulses with upper limb hypertension (right arm blood pressure 160/104 mm Hg). Echocardiography showed mild supravalvar aortic stenosis with a peak Doppler velocity of 2.0 m/s, moderate left ventricular hypertrophy, and suggested severe coarctation of the aorta distal to the left subclavian artery. Cardiac catheterisation was repeated in February 1997 when the patient was 9 years old. On this occasion, his systolic pressure gradient on withdrawal from the ascending to descending aorta was 44 mm Hg. Aortic angiography showed a long segment severe coarctation distal to the left subclavian artery (fig 1). Measurements performed at corresponding sites to the previous aortic angiography showed progressive coarctation, with a narrowest diameter of 2.6 mm, although there had been continued growth of the descending aorta distally measuring 10.9 mm. Five months later, he underwent end to end repair of coarctation with an interposition graft. Postoperative recovery was uncomplicated.
The speed of development of aortic coarctation in this child is remarkable (less than four years). This does not represent a failure of growth. There was progressive narrowing of the lumen of the aorta, with the narrowest diameter falling from 6.1 to 2.6 mm, although the widest lumen diameter distal to the site of coarctation increased over the same time interval, from 8.3 to 10.9 mm. Furthermore, the histopathological examination of the resected segment of aorta revealed an external diameter of 7.0 mm compared with an internal diameter of 2.6 mm. This severe luminal stenosis was largely the result of intimal proliferation, without obvious major medial hypertrophy, which is often described as an additional component of arterial wall thickening in this condition.5
Although the peripheral pulmonary artery stenoses of William’s syndrome tend to improve, other vascular lesions become worse.1 Acquired coarctation of the aorta, however, is rare.2 3 This case illustrates that the finding of weak femoral pulses in this situation may not be a reliable guide to the progression of coarctation, because of distal aortic hypoplasia. A high level of suspicion and regular echocardiographic follow up are necessary for the diagnosis of this unusual problem.