A porcine model of congenital heart defect with decreased pulmonary blood flow established and the evaluate of immature pulmonary vascular of morphological chang

Objective Artificial atrial septum defect combining pulmonary artery banding to create a model of congenital heart defect with decreased pulmonary blood flow to explore the morphological changes of immature pulmonary vascular. Methods Choose twenty piglets with about one to two-month-old, which are exclusively for experiment used. The piglets were randomly divided into three groups: normal control group (group C, n = 6), Small incisions on the right chest, produced a transient reduction in pulmonary blood; low-medium pulmonary artery stenosis groups ( group T1, n = 7 ) : Did artificial room septostomy creation by self-dilators which were delivered into the surface of the right atrium and controlled Systolic trans pulmonary artery banding pressure (Trans-PABP) at pressure of 20 - 30 mmHg; severe pulmonary artery stenosis groups ( group T2, n = 7): T2 were the same surgical procedures with group T1 ,and controlled Trans-PABP ≥ 30 -50 mmHg. Monitored ultrasound after operation , carried out 64-slice computed tomography scanning after one month, to measure the proximal vessel diameter and TransPABP , after two month surgical exploration on the left chest. When the animals were sacrificed, the heart and lung tissue was cut to measure atrial septal defect, pulmonary artery and the banding diameter. By weihgt elastic fiber and van Cieson staining to observe the morphological pathological changes, three groups took lung tissue with right middle lobe lateral segment about 1.0 cm × 0.8 cm × 0.8cm at the end of surgery and 2-months after operation respectively. Results The models were all successfully in the survival animal of the two test groups. One pig died from tracheal intubation accident in the C group, there was one case died due to bowel obstruction in the T1 group, And there were two cases died result from acute right heart failure and chronic heart failure respectively in T2 group. 64-slice CT angiography showed that BD was significantly lower than the AOD in the two test groups, the proximal pulmonary vascular expansion result from stenosis, distal pulmonary vascular scarce. Histopathology showed that the pulmonary artery inside diameter of T1 and T2 was significantly higher than group C(P ＜0. 05,P ＜ 0.01), and the NAPSC of two experimental groups were significantly lower than group C 2-month after operation( P ＜0.01).Conclusion This type of Piglet model is closer to clinical pathological and physiological ,64-slice spiral CT combined with lung histopathology observed for the evaluation of pulmonary vascular hypoplasia is a reliable method. Tunica media of pulmonary arterioles hypoplasia with the number reducing, with pulmonary artery banding increased,the degree of pulmonary arterioles hypoplasia gradually increased. Key words: Heart defects, congenital Animal testing alternatives Pulmonary artery Pathology Decreased pulmonary blood flow