日本小児循環器学会雑誌 Pediatric Cardiology and Cardiac Surgery

Bis-diamine was administered at a dose of 200 mg/kg to 40 pregnant rats on the 9th and 10th days of gestation. Following cervical dislocation of the rats on the 21st day, the fetuses were delivered by cesarean section and were frozen immediately in acetone cooled to −76°C with dry ice. Each frozen fetal thorax was cut transversely and the sectioned surface was serially photographed with a stereoscopic microscope (Wild Photomacroscope) at intervals of 500 µm. Of the 330 fetuses, 46 had tetralogy of Fallot and absent pulmonary valve (TF/APV).

In those with TF/APV, a large aorta was overriding a large ventricular septal defect. The right ventricular infundibulum was minimally stenotic, and the pulmonary valve was absent with a small residual ridge on the valve ring. The pulmonary arteries (PAs) were generally enlarged, particularly at the right and left pulmonary hilar regions, and compressed and obstructed the adjacent trachea and bronchi. The diameter of the enlarged PAs was equal to or as much as twice the diameter of the aorta. In normal fetuses, the diameter of the right and left PAs was half the aortic diameter. The bronchial obstruction in TF/APV extended peripherally. Pericardial and pleural effusions were mildly increased. Both ventricles were mildly enlarged. The thymus was either hypoplastic or absent. These pictures show wide-spread obstruction of the fetal trachea and bronchi in TF/APV.