The Primary Research Of Building Aortic Dissection Model On Pig And The Treatment Of Ascending Aortic Dissection

Background:TEVAR surgery is the senior protocol for the treatment of Stanford type B aortic dissection,but some problems such as visceral artery are involved in the dissection need to be insolved.We need some kind of stable dissection model in the big animals involving pigs and dogs and so on to testing some new stent grafts and to evaluate some new treatment protocals.At present there are some problems about making models in big animals,such as too short false lumen length,high mortality,too low achievement ratio of animal model,poor stability.In previous studies,the researchers often used swine as the experimental animal,but we found that the pigs with vascular anatomy and size more similar to human beings are more suitable for the study of aortic disease.We hope to be able to make more stable aortic dissection models in pigs.It’s a dilemma between the require of studying endovascular treatment on the ascending aortic dissection and the rare big animal model of the ascending aortic dissection,we need a simple but stable ascending aortic dissection model of big animal to enough the needing of present research.This research study how to make ascending aortic dissecion models of big animal based on descending aortic dissection models of pig.The morbidity and mortality of ascending aortic dissection are higher than descending aortic dissection,and some researches showed that the sugery group had a better prognosis than the medicine group.But some patients who suffers from cardiopulmonary disease or old age are unable to get surgery.Even after the treatment,the effect are not satisfactory because of these factors.Endovascular treatment with the character of minamally invasive could ignore these shortages,but the treatment of ascending aortic dissection with endovascular protocals have some problems to solve,such as coronary artery blood supply,the anchoring zone and some other issues.This research aims to explore feasibility of the treatment of ascending aortic dissection with endovascular protocals on models of ascending aortic dissection in pigs.Objective:(1)To build a stable Stanford type B aortic dissection in pigs’ aorta,and made some technical innovation and exploration,so as to accumulate experience of building Stanford type A aortic dissection model in pig.(2)To build a stable Stanford type A aortic dissection in pigs’ aorta,and new instruments can be evaluated on the model,to explore some new techniques.(3)Collect some data of the experimental pigs’ aorta,to prepare some basic data for the design of other stent grafts and other studies.Choose and prepare appropriate size stent grafts of the ascending aorta.(4)In order to explore the feasibility of endovascular treatment for the ascending aortic dissection on the models of pig,and to accumulate experience for further study in the clinical and experimental study.Methods:(1)8 healthy pigs were secleted to build the model of Stanford type B aortic dissection in the descending aorta using different methods,and summarize the best methods of building descending aortic model.(2)8 healthy pigs were secleted to build the model of Stanford type A aortic dissection in the descending aorta using different methods,and summarize the best methods of building descending aortic model.(3)CT contrast enhanced angiography was performed to analyze the morphological characteristics of ascending aorta.(4)In order to explore the feasibility of clinical application of ascending aortic dissection in the experimental animals,and to accumulate experience for further studies in the clinical and experient,treat the ascending aortic dissection of pigs with TEVAR.Results:(1)4 experiental studies was carried out in the descending aorta with water rush in the sheath.2 pigs were successfully build the model,and the other two were dead because of the anesthesia accident.The success rate of building models was 100%,and the total success rate was 50%.(2)4 experients were peformed in the experiental pigs’ descending aorta with the retrograde guidewire method,and 2 of them succeed,and the success rate of building models was 50%.(3)4 experients were peformed in the experiental pigs’ descending aorta with the separate intimal method,and all of them succeed,and the success rate of building models was 100%.(4)4 experients were peformed in the experiental pigs’ descending aorta with the pericardial method,and all of them succeed,and the success rate of building models was 100%.(5)The average weight of the experimental pigs was 51±4.2kg,and CT contrast enhanced angiography showed that the average diameter of the ascending aorta was 18.4±0.7mm,and the mean length of ascending aorta was about 28.5±2.9mm.(6)TEVAR performed for 2 times in the ascending aortic dissection model of pig with a cuff stent,and 1 of them succeed,the success rate was 50%.Conclusion:(1)The results showed that the method of arterial sheath with water flowing method and retrograde guidewire method could be used to build the model of descending aorta.Compared with open surgery and endovascular intervention,it is easier and more stable to build the model with open surgery.(2)A stable animal model can be established in the ascending aorta with the seprating intamal method and pericardial path method.(3)Endovascular treatment for the ascending aortic dissection of experimental pigs is feasible,but there are some problems needed to be solved.