Evaluation of Bicuspid Aortic Valves by Two-Dimensional Echocardiography

Abstract

M-mode echocardiography has proved useful in the identification of congenital bicuspid aortic valves. Characteristically, marked eccentricity of the cusp echoes within the aortic lumen in diastole is observed. This results in asymmetry of the systolic images of the aortic valve so that one leaflet appears to be larger than the other. An additional frequent finding in patients with bicuspid aortic valves is the presence of multilayered echoes in diastole in the absence of fluoroscopic or pathological evidence of valvular calcification. Redundant leaflet tissue normally present in bicuspid aortic valves probably produces folds whose diastolic position may vary in different cardiac cycles giving rise to asymmetry and variability of diastolic cusp position. Asymmetric leaflet images may also be due to the unequal size of the leaflets. However, both false positive and false negative diagnoses have been made. A midline aortic valve diastolic cusp position may be obtained from a single transducer position and false positives have been obtained in conditions with abnormal position or distortion of the aortic root, such as sinus of Valsalva aneurysm.