ABSTRACT
Anatomy In congenital aortic valve stenosis, the aortic annulus may be hypoplastic to some extent, the leaets may be thickened, and the commissures may be fused to varying degrees. Dysplastic or unicuspid valves (Figure 21.1a) oen seen in newborns are present in about 10% of infants and 3% of older children in whom the treatment is indicated. Trileaet valves (Figure 21.1b) are seen in 25% of infants and 40% of older patients who require treatment. e majority of the stenotic valves are bicuspid.1 ere are two forms of bicuspid aortic valves: balanced or “anatomically bicuspid” and unbalanced or “functionally bicuspid.” e “anatomically bicuspid” valve is composed of two equalsized cusps with two sinuses of Valsalva (Figure 21.1c). e “functionally bicuspid” valve also opens as bicuspid, but it has three sinuses, two of them adjacent to a fused cusp, which is actually formed by two unequal cusps conjoined by an unopened commissure. e fused cusp is larger than the opposite one, hence “unbalanced bicuspid valve” (Figure 21.1d). is anatomical concept is important in regard to the prognosis of the valvuloplasty.1 In the balanced bicuspid valves as well as in trileaet stenotic valves, the orices are usually enlarged by splitting of the functioning commissures, whereas in the unbalanced bicuspid valves, the fused cusp is oen torn aside from the rudimentary commissure (Figure 21.2),2 presumably due to unequal rigidity of the dierent-sized cusps.
