Desarrollo de un equipo transportador de prótesis bifurcada monopieza autoexpandible para su introducción, fundamentalmente en el sistema vascular, sistema traqueobronquial y en la vía biliar, por técnicas percutáneas propias de la radiología intervencionista

Abstract

In the context of atherosclerosis, such as widespread disease, it is very often the development of stenotic lesions in main vascular bifurcations as for example the aortic bifurcation in the Leriche syndrome, the carotid artery in stroke or coronary artery in myocardial ischemia. Endovascular treatment of these injuries requires complicated angioplasty maneuvers or multiple stent placements (frequently with intravascular overlapping) to adequately cover the branches. Abdominal aortic aneurysm, also related to the arterial wall degeneration, usually involves the bifurcation. The endovascular approach to these lesions requires access by both femoral arteries and several endovascular stent overlap. On the other hand, the development of biliary and bronchial carcinomas frequently spreads to the tracheobronchial and biliary bifurcations, and thereby, significantly impedes possible palliative treatment by stenting, which would avoid or reduce stenosis and obstruction. Hypothesis: The hypothesis of this thesis and principal objective proposed in this technological biomedical research is to demonstrate the possibility of building a truly self-expanding bifurcated stent prototype, in one piece, Y-shaped, and their respective carrier-releasing device to deliver it in different animal anatomical bifurcations by a single percutaneous access. This has been rated during the implant placement, experimenting different difficulty degrees in the access and release of the different prototypes, depending on the device characteristics. Materials and methods: Several models of stents have been built by manual suture binding of self-expanding and monotubular stents to form a single Y-structure, with a main body and two distal branches. Models with different characteristics and compositions were used: Gianturco-Roch, Smart, Symphony, Zilver, ZA and Sprinter. From conventional catheters and introducers a carrier-releasing device was built, which allows the independent release of each distal branch (by distal pushing) and the main body of the stent (by pulling back) in the chosen anatomical bifurcation. These stents were tested for in vitro release and placement in swine anatomical bifurcations: inferior vena cava, aorta, carotid trunk and tracheobronchial tree, with seven models per each of the six prototypes of bifurcated stents built. Results: It has been technically possible to build truly bifurcated stents and a new carrier-releasing device. The manual construction of both generates structures with some areas of increased friction and stiffness (sutures, liquid adhesive joints, etc). It has been technically possible to release and expand them in different bifurcations. Although no statistically significant differences were shown between the different stent groups, neither in the access simplicity to the bifurcation nor in the release of the stent, the procedure was better with Sprinter stent model. Conclusions: We can compose a truly bifurcated stent and a carrier-release system which allows access, with a single percutaneous puncture, to different anatomical bifurcations. The bifurcation access and stent release is independent of materials used in our investigation. The braided nitinol stent, closed cell with attached and atraumatic ends has allowed an easier procedure.