Absent pulmonary valve with tricuspid atresia or severe tricuspid stenosis: Report of three cases and review of the literature

Absence of the pulmonary valve occurs usually in association with tetralogy of Fallot and occasionally with an atrial septal defect or as an isolated lesion. Very rarely it occurs with tricuspid atresia, intact ventricular se ptum, and dysplasia of the right ventricular free wall and of the ventricul ar septum. We present the clinical, anatomic, and histologic findings of a new case, and for the first time, the data from two patients with absent pu lmonary valve and severe tricuspid stenosis, who exhibited similar histolog ic findings. We also reviewed the clinical and anatomic data of 24 previous ly published cases and compared them with the new cases. In all three new c ases, the myocardium of the right ventricle was very abnormal. In the two c ases with tricuspid stenosis, large segments of myocardium were replaced wi th sinusoids and fibrous tissue. In the case with tricuspid atresia, the ri ght ventricular free wall contained only fibroelastic tissue. The ventricul ar septum in all three patients showed asymmetric hypertrophy and in two of the three patients, multiple sinusoids had replaced large segments of myoc ardial cells. The left ventricular free wall myocardium and the walls of th e great arteries were unremarkable. Our data indicate that myocardial deple tion involving the right ventricular free wall and the ventricular septum a nd its replacement by sinusoids and fibroelastic tissue occur not only in c ases of absent pulmonary valve with tricuspid atresia but also in cases of absent pulmonary valve with tricuspid stenosis. The degree of myocardial de pletion varies and is more severe when the tricuspid valve is atretic.