Patch of polydimethylsiloxane reinforced with polyester fabric for aortic angioplasty in rabbits

Introdução: Apesar de bons resultados descritos na literatura, o substituto ideal para a utilização como remendo no fechamento arterial ainda não existe. Por este motivo, ainda há espaço para a busca por remendo que seja biocompatível, e que apresente facilidade de manuseio e resultados satisfatórios. Avaliamos remendos arteriais de silicone (polidimetilsiloxano com reforço em poliéster - PDMSr) em comparação com remendos arteriais de PTFEe. Objetivo: O objetivo deste trabalho é comparar, em modelo experimental, em coelhos, os resultados de remendos arteriais feitos em PDMSr com remendos de PTFEe. Materiais e Método: A amostra foi definida em 10 animais que completassem todas as etapas da pesquisa em cada grupo. Os animais foram submetidos à laparotomia mediana e abertura longitudinal da aorta de aproximadamente 8mm, realizando-se o seu fechamento com remendo do grupo selecionado, seguido do fechamento por planos. Os animais foram mantidos em biotério até o 60º PO, quando, então, realizou-se arteriografia de controle, e análise macro e microscópica de peça. Resultados: Para se atingir a amostra desejada, foram necessários 12 procedimentos no grupo PDMSr e 16 no grupo PTFEe. Ocorreram 2 óbitos no grupo PDMSr e 6 no grupo PTFEe. Apesar do número maior de óbitos no grupo PTFEe não houve diferença estatística na sobrevida entre os grupos. Um animal do grupo PDMSr apresentou monoparesia em pata posterior direita e um animal do grupo PTFEe apresentou hérnia incisional. Não houve diferença estatística nas complicações entre os grupos. O tempo operatório foi estatisticamente maior no grupo PTFEe quando comparamos todos os animais, fato que não se repetiu quando excluímos os animais que faleceram. O peso e o tempo operatório foram estatisticamente maiores nos animais que morreram. Todos os animais que chegaram ao final do tempo de estudo apresentavam aorta patente. Na análise macroscópica da peça, houve, estatisticamente, maior reação tecidual periprótese no grupo PTFEe. A microscopia eletrônica de varredura evidenciou cobertura de todo o remendo de PDMSr por tecido similar ao endotélio, enquanto, nos remendos de PTFEe, o crescimento limitou-se às bordas da linha de sutura e ilhas isoladas no seu centro. Conclusão: O material estudado apresentou resultados comparáveis ao do PTFEe, porém com menor reação tecidual local e maior proliferação celular para a luz do vaso. Apesar de novos estudos serem necessários, inclusive para avaliação de uso em humanos, o presente estudo apresenta resultados promissores que encorajam a continuidade de sua pesquisaIntroduction: Although good results are reported for various materials for use as patches for arterial closure, as yet none of these is ideal. Therefore, research is continuing into development of a patch that is biocompatible and provides ease of handling, while having satisfactory outcomes. A new silicone arterial patch (polydimethylsiloxane reinforced with polyester fabric, PDMSr) was compared with patches made of expanded polytetrafluoroethylene (ePTFE). Objective: To compare the outcomes between arterial patches made of PDMSr with those made of ePTFE, in an experimental rabbit model. Materials and Method: Rabbits were placed in two groups, and received either PDMSr or ePTFE arterial patches (PDMSr group and ePTFE group, respectively). The animals underwent laparotomy and longitudinal opening of the aorta, which was then closed with the selected patch, followed by suture of all layers. The animals were kept in their cages until the 60th postoperative day, when arteriography, removal of the aorta, and macroscopic and optic and scanning electron microscopic analyzes of the aorta were performed. Ten rabbits from each group that had completed all stages of the research were included in analyses. Results: Twelve procedures were performed in the PDMSr group and 16 in the ePTFE group. There were 2 deaths in the PDMSr group and 6 in the ePTFE group. Despite the higher number of deaths in the ePTFE group, there was no statistical difference in survival rate between the groups. One animal in the PDMSr group developed monoparesis in its right hind paw and 1 animal in the ePTFE group had an incisional hernia. There was no statistical difference in complications between the groups. The operative time was significantly longer in the ePTFE group when all animals were included in analysis, but not when animals that died were excluded. Body weight was significantly greater and operative time was significantly longer in animals that died. Postsurgical aortic patency in the survival animals was 100% in both groups by arteriography. Macroscopically, tissue reaction around the prosthesis was greater in the ePTFE group (statistically significant). Microscopically, the PDMSr patches were entirely covered with a cellular endothelium-like tissue, while tissue growth on the ePTFE patches was limited to the edges of the suture line and to isolated central islands. Conclusion: The two materials showed comparable outcomes; however, PDMSr showed cellular proliferation to the entire graft, and less local inflammatory reaction compared with ePTFE. Although further studies are required, including assessment in humans, the results of the present study indicate that PDMSr shows promise as an arterial patch materia

Experimental comparative study of arterial implants made of silicone reinforced with polyester fabric and expanded polytetrafluoroethylene (PTFE) in rabbits aorta

ABSTRACT Objectives: the aim of this study was to compare the outcomes of a new silicone vascular prostheses with PTFE vascular prostheses, on a rabbit experimental model. Methods: forty rabbits underwent infra-renal aorta replacement with 4 mm diameter prostheses, twenty animals with PDMS and twenty animals with PTFE (control group). Retrograde aortic angiography was performed to assess patency. Histological graft samples were examined by electron microscopy to evaluate prostheses endothelialization. Results: patency rates were 100% for both grafts after 30 days; after 60 days, patency rate for PDMS was 92.3% (±7.4), and 73,8% (±13.1) at 90 days. PTFE grafts had patency rates of 87.5% (±11.7) at 60 and 90 days. No statistically significant difference was found in between groups for patency rates (p=0.62). Postoperative complications (death, paraplegia) rates (p=0.526) and aortic clamping times (p=0.299) were comparable in both groups. No statistically significant difference for stenosis was found on angiographical analysis between groups (p=0.650). Electron microscopy revealed limited anastomotic endothelial ingrowth in both prostheses. Conclusion: in this experimental model, PDMS and PTFE vascular prostheses had comparable outcomes and PDMS prosthesis could be used as a vascular graft.</jats:p

Lateral approach to the peroneal artery without resection of the fibula for lower limb revascularization

The peroneal artery is an important outflow vessel for lower limb revascularization and limb salvage. This vessel is commonly reached using a medial, posterior, or lateral approach with resection of the fibula. We present a technique of lateral approach to the peroneal artery without fibular resection