Pathology of coronary arteries, myocardium, and great arteries in supravalvular aortic stenosis. Report of five cases with implications for surgical treatment.

Among five patients with supravalvular aortic stenosis in whom autopsy tissues were available, all were male, 1 1/2 to 39 years old (mean 10 years, median 3 years), and the four children had Williams-Beuren syndrome (two familial, two sporadic). Medial thickening and dysplasia (disorganization) characterized the aortic sinotubular junction of three patients with discrete disease and the entire ascending aorta and arch branches of the two with diffuse disease. Medial dysplasia also involved the pulmonary arteries in each case, but less severely than the aorta. Dysplasia of coronary arteries was observed in all five hearts and was more obstructive proximally than distally, in cases with diffuse than discrete aortic disease, and in the adult than in the two children with discrete supravalvular aortic stenosis. All major epicardial arteries were involved, without predilection for any particular vessel. In contrast to the great arteries, coronary artery dysplasia involved all three layers, not just the media. To varying degrees, vessels showed intimal hyperplasia, fibrosis, and disorganization (dysplasia); disruption and loss of the internal elastic membrane, with indistinct intimal-medial junctions; medial hypertrophy and dysplasia; and adventitial fibroelastosis. In severe cases, the microscopic structure resembled that of the ductus arteriosus. Acute intramedial dissections were observed in the ascending aorta and distal right coronary artery in one patient each. Chronic microfocal ischemic fibrosis was identified in the subendocardium and papillary muscles of the left ventricle in four patients, and the adult patient also had an acute myocardial infarction. In summary, these findings emphasize the extraaortic extent of supravalvular aortic stenosis and the development of ischemic heart disease even in childhood. The presence of severe coronary obstruction in the adult with discrete aortic disease suggests that chronic high pulsatile coronary blood pressure may favor the proliferation of dysplastic tissue. Early surgical intervention may minimize the degree of proliferation, as well as allow regression of left ventricular hypertrophy, thereby lessening the risk of myocardial ischemia and aortic dissection.