Cross-sectional echocardiographic assessment of aortic obstruction.

Cross-sectional echocardiographic features of aortic obstruction occurring at multiple levels of the left ventricular outflow tract are discribed. Specific pathologic entities considered include coarctation of the aorta, supravalvular, valvular, and discrete subvalvular aortic stenosis, as well as functional or idiopathic hypertrophic subaortic stenosis. At each of these levels the cross-sectional method permits direct visualization of the obstructing lesion, it's morphologic characteristics, and extent. In addition the relationship of the area of obstruction to more normal surrounding areas of the outflow tract can be assessed. Studies at the supravalvular and valvular levels indicate the direct imaging of the stenotic area may permit estimation of severity. At the subvalvular level the patterns of development of functional obstruction can be examined and the mechanisms of this type of obstruction further illucidated. Finally in addition to direct visualization of individual areas of obstruction it is possible to detect or exclude areas of concommittant obstruction at other levels of the outflow tract. Cross-sectional echocardiography therefore represents a rapid, non-invasive method for visualizing the location, extent, severity, and dynamic nature of lesions producing obstruction to left ventricular outflow.