Natural course of supravalvar aortic stenosis and peripheral pulmonary arterial stenosis in Williams' syndrome

We investigated the catheterization and angiographic findings of 26 patient s with Williams' syndrome to evaluate the natural course of supravalvar aor tic stenosis and peripheral pulmonary arterial stenosis. The severity of th e stenosis was correlated with age and body surface area in terms of the pu lmonary arterial index, right ventricular systolic pressure, sinutubular ra tio(ratio of measured to mean normal diameter of sinutubular junction), and systolic pressure gradient across the sinutubular junction. In patients with pulmonary arterial stenosis (n=20), right ventricular syst olic pressure tended to decrease, and pulmonary arterial index increased, w ith increase in age and body surface area. Between the groups with and with out pulmonary arterial stenosis, there was significant difference in age (m ean 4.70 vs. 9.87, p=0.019), body surface area (0.62 vs. 1.16, p=0.002), pu lmonary arterial index (152 vs. 317, p=0.002) and right ventricular systoli c pressure (73.9 vs. 33.0, p=0.006). As all patients showed similar diamete rs at the sinutubular junction regardless of age and body size, sinutubular ratio decreased with increases in age and body surface area. The group wit h abnormal coronary arteries (n=7) had smaller sinutubular ratio (0.46 vs. 0.61, p=0.021) and higher pressure gradients between the left ventricle and the aorta (67.6 vs. 42.2, p=0.023) than did the group with normal coronary arteries. Stenosis of a coronary artery, or a branch of the aortic arch, w as observed only in three patients with diffuse aortic stenosis. Our results suggest that, with time, peripheral pulmonary arterial stenosis tends to improve, and supravalvar aortic stenosis to progress. Failure of growth of the sinutubular junction might be responsible for the progression of the aortic lesion. Progression of the aortic lesion may be associated w ith involvement of the coronary arteries.