Surgical pathology of the truncal valve: a study of 12 cases.

The truncal valves of 12 patients (eight females and four males) who had undergone valve replacement were studied. The patients ranged in age from 14 months to 21 years (mean, 10 years). All truncal valves were purely regurgitant: nine were severe, two were moderate, and one was mild. Eight of the valves were tricuspid, two were bicuspid, one was quadricuspid, and one was unicommissural. Each valve was thickened, but none was the site of endocarditis. The thickening tended to be greatest along the distal portion of each cusp and resulted primarily from expansion of the spongiosa and fibrosa layers. In seven of the 12 valves, the spongiosa disrupted the fibrosa. In 11 valves, fibrous pads were also observed along the cuspid surfaces. These histopathologic features are indistinguishable from those described for floppy mitral valves and support the concept that floppy valves may result from a congenital abnormality in valvular structure.