Avaliação biomecânica da fixação das endopróteses com e sem cola biológica e alterações histológicas aórticas. Estudo experimental em porcos
Data
2009-09-15
Autores
Almeida, Marcelo José de [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A migração da endoprótese é uma complicação do tratamento endovascular definida como deslocamento de sua ancoragem inicial. Para avaliação da migração verifica-se a posição da endoprótese em relação à determinada região anatômica. Considerando o aneurisma da aorta abdominal infra-renal, a área proximal de referência consiste na origem da artéria renal mais baixa e, na região distal, situa-se nas artérias ilíacas internas. Os pacientes deverão ser monitorizados por longos períodos a fim de serem identificadas migrações visto que estas ocorrem normalmente após 2 anos de implante. Para se evitarem migrações, forças mecânicas que propiciam fixação e determinadas por características dos dispositivos e a incorporação da endoprótese, devem predominar sobre forças gravitacional e hemodinâmica que tendem a arrastar a prótese no sentido caudal. Angulação, extensão e diâmetro do colo, além da medida transversa do saco aneurismático, são importantes aspectos morfológicos do aneurisma relacionados à migração. Com relação à técnica, o implante de endopróteses com sobredimensionamento excessivo (>30%) não é recomendado por provocar dilatação do colo do aneurisma, além de dobras e vazamentos proximais que também contribuem para migração. Por outro lado, endopróteses com mecanismos adicionais de fixação (ganchos, farpas e fixação supra-renal) parecem estar menos associadas às migrações. O processo de incorporação das endopróteses ocorre parcialmente e parece não ser suficiente para impedir migrações tardias. Neste sentido, estudos experimentais com endopróteses de maior porosidade e uso de substâncias que permitam maior fibroplasia e aderência da prótese à artéria vem sendo realizados e parecem ser promissores. Nesta revisão estes aspectos serão discutidos, em especial o uso da cola de fibrina.
Migration of the endoprosthesis is a complication of the endovascular treatment defined as misplacement of its initial fixation. In order to assess such migration, one shall verify the position of the endoprosthesis in relation to the determined anatomic site. Considering the aneurysm of the infra-renal abdominal aorta, the proximal area of reference consists on the origin of the lowest renal artery and, at the distal region, it is located next to the internal iliac arteries. Patients shall be monitored for long periods so that migrations can be spotted; these migrations usually occur 2 years after the implant. To avoid migration mechanical forces that enable fixation and that are determined by features of devices as well as the incorporation of the endoprosthesis have to predominate over gravitational and hemodynamic forces, which tend to drag the prosthesis toward to caudal direction. Angulation, extension and diameter of the neck, and transversal measure of the aneurysmatic sac, are important morphological aspects related to migration. In relation to technique, the implant of endoprosthesis with excessive oversizing (>30%) is not recommended because it leads to aortic neck dilatation, folds and proximal leaking witch contribute to its migration. On the other hand, endoprosthesis with additional fixation devices (hooks, barbs and supra-renal fixation) seem to be less associated with migration. The process of incorporation of the endoprosthesis occurs partially and does not seem to be enough to prevent later migrations. In this sense, experimental assessment with higher porosity endoprosthesis as well as the use of substances that allow higher fibroplasia and adherence of the prosthesis to the artery have been made and look promising. In this review, such aspects are discussed, specially the use of fibrin glue.
Migration of the endoprosthesis is a complication of the endovascular treatment defined as misplacement of its initial fixation. In order to assess such migration, one shall verify the position of the endoprosthesis in relation to the determined anatomic site. Considering the aneurysm of the infra-renal abdominal aorta, the proximal area of reference consists on the origin of the lowest renal artery and, at the distal region, it is located next to the internal iliac arteries. Patients shall be monitored for long periods so that migrations can be spotted; these migrations usually occur 2 years after the implant. To avoid migration mechanical forces that enable fixation and that are determined by features of devices as well as the incorporation of the endoprosthesis have to predominate over gravitational and hemodynamic forces, which tend to drag the prosthesis toward to caudal direction. Angulation, extension and diameter of the neck, and transversal measure of the aneurysmatic sac, are important morphological aspects related to migration. In relation to technique, the implant of endoprosthesis with excessive oversizing (>30%) is not recommended because it leads to aortic neck dilatation, folds and proximal leaking witch contribute to its migration. On the other hand, endoprosthesis with additional fixation devices (hooks, barbs and supra-renal fixation) seem to be less associated with migration. The process of incorporation of the endoprosthesis occurs partially and does not seem to be enough to prevent later migrations. In this sense, experimental assessment with higher porosity endoprosthesis as well as the use of substances that allow higher fibroplasia and adherence of the prosthesis to the artery have been made and look promising. In this review, such aspects are discussed, specially the use of fibrin glue.
Descrição
Palavras-chave
Cirurgia vascular - Técnicas - Estudos experimentais, Vascular prosthesis, Aortic aneurysm
Como citar
ALMEIDA, Marcelo José de. Avaliação biomecânica da fixação das endopróteses com e sem cola biológica e alterações histológicas aórticas. Estudo experimental em porcos. 2009. 72 f. Tese (doutrado) - Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, 2009.