CLINICAL ANATOMY OF THE NORMAL PULMONARY ROOT COMPARED WITH THAT IN ISOLATED PULMONARY VALVULAR STENOSIS

Objectives. This study aimed to clarify the clinical anatomy of the pu lmonary root. Background. Many descriptions of valvular anatomy have f ocused on the annulus, leading to varied interpretations of abnormal v alves. Methods. Twenty-two heart specimens with isolated pulmonary val vular stenosis were examined to analyze the gross structure of the pul monary root. For comparison, we examined a normal series of a similar age range together with nine adult hearts. Serial histologic sections were prepared from five specimens. Results. The normal pulmonary valve is enclosed in a proximal sleeve of free-standing right ventricular i nfundibulum supporting the fibroelastic walls of the pulmonary sinuses at the anatomic ventriculoarterial junction. The valvular leaflets ar e attached in semilunar fashion across this junction, delimiting the e xtent of the valvular sinuses. The stenotic valves were separated into dome-shaped valves, dysplastic valves and a third group of less typic al cases. In the dome-shaped valves, which had a relatively circular o rigin of their leaflets, three raphes were tethered to the arterial wa ll at the sinutubular junction, producing a waistlike narrowing. The l eaflets of the dysplastic valves were attached in a relatively normal semilunar fashion, but stenosis was caused by thickening of the leafle ts at their free edges. Serial histologic sections through normal and abnormal valves failed to demon demonstrate any well defined fibrous ' 'annulus'' that could be of clinical relevance. Conclusions. Unlike th e normal and the dysplastic valves, the dome-shaped valves have circul ar rather than semilunar lines of attachment of the valvular leaflets. Liberation of the fused zones of apposition of the leaflets within th e dome is unlikely to restore such abnormal valves to normal structure , even if this procedure relieves the stenosis. (C) 1998 by the Americ an College of Cardiology.