“…Occasionally, membranous obstruction occurs just above the pulmonary valve (Franch and Gay, 1963;Arvidsson et al, 1961;Smith, 1958). Pulmonary artery stenosis may be unilateral (Luan et al, 1960) or bilateral (Agustsson et al, 1962), single or multiple (D'Cruz et al, 1964); it may involve a localized arterial site with poststenotic dilatation or varying lengths of a branch from segmental narrowing to diffuse tubular hypoplasia (D'Cruz et al, 1964;Franch and Gay, 1963). Though pulmonary artery stenosis occurs as an isolated congenital malformation, it frequently coexists with other anomalies, especially valvular pulmonary stenosis (Hall et al, 1961;Franch and Gay, 1963;D'Cruz et al, 1964;Rowe, 1963), atrial septal defect (Shafter and Bliss, 1959;Franch and Gay, 1963), ventricular septal defect (D'Cruz et al, 1964), patent ductus arteriosus (Rowe, 1963;D'Cruz et al, 1964;Venables, 1965), and Fallot's tetralogy (Baum et al, 1964;D'Cruz et al, 1964).…”