Gradual Increase In The Comparative Study Of Ventricular Training Under The Pressure Of The Young And The Elderly Small Tail Han Sheep

Objective To evaluate the effectiveness of a new adjustable pulmonary artery banding device.Methods 12 male sheep,5～6 months old,26～37kg, were randomly divided into experimental and control group, each comprising 6 animals (respectively 29.00±2.78 kg, and 28.36±4.24 kg, no statistically significant difference). After opening the chest through the second left intercostal, pulmonary trunk was dissociated and the adjustable pulmonary artery banding device was put around it. Then the balloon of the device was gradually inflated to narrow the pulmonary artery and to train the right ventricle. The shape of the right ventricle was studied by echocardiogram and the changes of the hemodynamic and myocardial histopathology were observed.Results Observed by echocardiogram, the shape and the thickness of right ventricle and the position of septum were different from that before training. Results of hemodynamic showed that the ratio of right ventricular contraction pressure to the left had got the goal of clinical practice (greater than 0.6). Both the systolic function (P< 0.05) and diastolic function (P<0.001) were enhanced. The thickness and the quality of right ventricle, right ventricular hypertrophy index and cardiac myocyte diameter were significantly different from the control group in pathological examination (P< 0.001).Conclusion This device was able to achieve the aim of pulmonary artery banding and ventricular training. Furthermore, it may implement the dual-adjustment, easily and efficiently. Objective To compare the diffirence of the right ventricle training between the young and old sheep induced by gradually increasing the after load.Methods 12 male sheep,5～6 months old,26～37kg, were randomly divided into experimental and control group, each comprising 6 animals (respectively 29.00±2.78 kg, and 28.36±4.24 kg, no statistically significant difference); 12 male sheep, 5～6 years old,72～83kg, were randomly divided into experimental and control group, each comprising 6 animals (respectively 75.63±4.57 kg, and 76.38±3.62 kg, no statistically significant difference). After opening the chest through the second left intercostals, pulmonary trunk was dissociated and the adjustable pulmonary artery banding device was put around it. Then the balloon of the device was gradually inflated to narrow the pulmonary artery and to train the right ventricle. The shape of the right ventricle was studied by echocardiogram and the changes of the hemodynamic and myocardial histopathology were observed.Results Young and old sheep both were able to achieve the aim of ventricular training (right ventricular pressure/left ventricular pressure greater than 0.6).After training the right ventricular systolic and diastolic function of the two groups were enhanced, although the added value of±dp/dt in the young sheep were higher than old, but there was no statistical significant difference between the two groups. Pathological results showed that both right ventricular hypertrophy index were both added, but no significant difference. The degeneration of myocardial cells, interstitial edema, focal fibrosis and a small number of pathological changes such as fatty degeneration were observed in the old experimental group myocardial histopathology, liver biopsy showed central venous congestion and expansion of sinusoidal liver cells such as hepatic congestion with mild degeneration performance.Conclusion The young and old sheep were able to achieve the aim of ventricular training by gradually increasing the after load, but the old sheep occurred myocardial pathologic changes and heart dysfunction, which needs our further study.