Size of the normal aortic root in normal subjects and in those with left ventricular outflow obstruction

This study establishes normal values and growth curves of the aortic root to determine when it is unusually small. The aortic root diameter was measured by 2-dimensional echocardiography in 188 normal subjects (group 1) and in 33 patients (group 2) with left ventricular outflow obstruction in whom the diagnosis of small aortic root was made during surgery for aortic root and valve replacement. In group 2 the aortic root was also measured by M-mode echocardiography and was compared to measurements during surgery. Growth curves of the normal aortic root were obtained. In group 2 the aortic root was smaller than normal except in 3 patients. When corrected for body surface area all were smaller than normal. The 2-dimensional echocardiographic and surgical measurements were almost identical. M-mode values were higher (p less than 0.01). The normal values and growth curves of the aortic root diameter are thus established and the small aortic root can be identified preoperatively.