MORPHOLOGY OF TRICUSPID-VALVE IN PULMONARY ATRESIA WITH INTACT VENTRICULAR SEPTUM

Pulmonary atresia with intact ventricular septum (PAIVS) is a rare con genital cardiac anomaly that has been classified into two types: one i s a more frequent type having dysplasia of tricuspid valve (TV) with a small annulus, underdeveloped right ventricle (RV) with a hypoplastic cavity and a hypertrophic wall; the other type has severe dysplasia o f TV and dilatation of RV, right atrium (RA), and right atrioventricul ar junction with thinning of the RV wall. We performed a morphologic s tudy on 11 autopsied hearts with PAIVS, giving particular emphasis to the variation of morphology of the TV. We could classify these hearts into 3 groups according to the degree of right ventricular development . In the first group of 7 cases (type I), the RVs were underdeveloped. Thick leaflets, restricted valve apparatus with short chordae, and sm all annuli were characteristics of the TV. In the second group of 3 ca ses (type II), the RVs showed marked enlargement of the cavity and thi nning of the wall. The TV showed redundant, dysplastic, sail-like ante rior leaflets, and the downward displacement of septal leaflet and/or posterior leaflet, which are the findings frequently observed in Ebste in's malformation. The RVs were dilated and with partially unguarded t ricuspid orifice. The septal leaflet of the TV was dysplastic and, in two cases, the septal leaflet showed chordal structure at the upper su rface facing the RA, which is a peculiar finding that has not been des cribed in the Literature. The remaining case was a heart with a modera tely developed RV (type III). The TV showed mildly dysplastic appearan ce and we classify this as a separate type, because we could expect th e best surgical results in this type. This type had optimal size of RV and the mildest degree of dysplasia of TV. In PAIVS, the morphology o f TV correlates well with the type of the right ventricular developmen t.