Procedure and Techniques The aortic valve in these patients is most often The dilation can be approached from either a myxomatous and bicuspid with a single, fused retrograde or antegrade direction. Remember commissure and an eccentrically placed orifice, that critical AS is a case of millimeters?so you or unicuspid (dome-shaped). The valve annulus need to be meticulous. may be small for age, but there is evidence that following dilation even quite small annuli may grow to a normal or near normal dimension (1). Retrograde Approach Myxomatous valves may mature, as Myxo- tous pulmonary valves. Because there is a spec- This is the more common approach at Children?s trum to left-sided obstructive lesions, often the Hospital Boston since the production of l- first decision in many of these patients is whether profile balloons. Often the umbilical artery and they should have a valvotomy or a staged o- vein already have been cannulated, and may be ventricle repair.