Impact of endoprosthesis oversizing in thoracic aorta: experimental study in a porcine model

• Grant number: 09/17759-4
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2010
• End date: February 28, 2011
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Erasmo Simão da Silva
• Grantee: Erasmo Simão da Silva
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The endovascular repair of aortic disease has been expanding rapidly, being particularly promising in thoracic aortic trauma. The traumatic rupture of the thoracic aorta is the second leading cause of death by traffic accident. The repair with endovascular stent graft has lower mortality and paraplegia compared to open surgery, however the long-term results are still doubtful. The commercially available prostheses are designed to aneurysmal disease, with a diameter much greater than the diameter of the aorta of young people. This "oversizing" can lead to mechanical changes in the interaction of the prosthesis with the aortic wall, affecting the vasculature, causing transmural inflammation and weakening of the aortic wall and neighboring organs such as the esophagus. The objective of this study is to analyze, from an experimental animal model, the effect on the non-atherosclerotic aorta of 4 different levels of oversizing of stents. Methods: 25 pigs will be used (race: Large White), divided into 5 groups, each group with 5 animals. A group of 5 pigs will be the control group. All thoracic prosthesis deployed will be Medtronic (donated), in sizes from 24 to 34 mm in diameter. The 4 groups will be divided as oversizing: Group A: 10 - 19%, Group B: 20 - 29%, Group C: 30 - 39% and Group D: more than 40%. The hypothesis tested in this study is that an oversizing greater than 30% can lead to serious structural change in the aortic wall. For that, we will study the aorta with arteriography, biomechanics, pathology and immunohistochemistry after 4 weeks of the stent-graft implantation. (AU)