RESUMO
OBJECTIVE: To investigate the effects of removal of the adventitia on the tunica media in a pig model. METHODS: The experiment was performed in eight pigs. The adventitia of the descending aorta was removed. Following euthanasia, at two, four, six and eight weeks, the aortic segment was removed. Next, slices of the aorta were stained with hematoxylin and eosin (HE) and Weigert-Van Gieson. RESULTS: After two weeks there was a slight cellular breakdown in the outer third of the media. After four weeks structural breakdown of elastic fibers was observed in the outer two thirds of the same layer. In six weeks, several areas of necrosis and almost complete disruption of elastic fibers were identified. Finally, after eight weeks, there was fibrosis of the entire wall with disruption of the internal elastic lamina. CONCLUSION: The removal of the adventitia leads to degeneration of the media, determining loss of the normal structure of the aortic wall that is variable in its location, intensity and shape, depending on the length and duration of the ischemic insult.
Assuntos
Aorta Torácica/cirurgia , Tecido Conjuntivo/cirurgia , Túnica Média/cirurgia , Animais , Aorta Torácica/patologia , Feminino , Suínos , Túnica Média/patologiaRESUMO
OBJETIVO: Investigar os efeitos da remoção da adventícia da aorta em suínos. MÉTODOS: O experimento foi realizado com oito suínos. Removeu-se a camada adventícia da aorta descendente. Após a eutanásia com duas, quatro, seis e oito semanas, o segmento aórtico era removido. Após, eram feitos cortes histológicos com a coloração de hematoxilina e eosina (HE) e pelo método de Weigert - Van Gieson. RESULTADOS: Após duas semanas identificou-se um leve desarranjo do terço externo da túnica média. Nos animais sacrificados após quatro semanas observou-se um desarranjo estrutural dos terços externos da túnica média. Após seis semanas observou-se necrose da parede aórtica. Finalmente, após oito semanas além da fibrose da parede aórtica identificou-se a destruição da lâmina elástica interna. CONCLUSÃO: A remoção da adventícia da aorta em suínos levou à alterações degenerativas da média, determinando perda da estrutura da parede aórtica que é variável em sua localização, intensidade e forma, dependendo do tempo a partir do qual se estabeleceu a lesão isquêmica.
OBJECTIVE: To investigate the effects of removal of the adventitia on the tunica media in a pig model. METHODS: The experiment was performed in eight pigs. The adventitia of the descending aorta was removed. Following euthanasia, at two, four, six and eight weeks, the aortic segment was removed. Next, slices of the aorta were stained with hematoxylin and eosin (HE) and Weigert - Van Gieson. RESULTS: After two weeks there was a slight cellular breakdown in the outer third of the media. After four weeks structural breakdown of elastic fibers was observed in the outer two thirds of the same layer. In six weeks, several areas of necrosis and almost complete disruption of elastic fibers were identified. Finally, after eight weeks, there was fibrosis of the entire wall with disruption of the internal elastic lamina. CONCLUSION: The removal of the adventitia leads to degeneration of the media, determining loss of the normal structure of the aortic wall that is variable in its location, intensity and shape, depending on the length and duration of the ischemic insult.
Assuntos
Animais , Feminino , Aorta Torácica/cirurgia , Tecido Conjuntivo/cirurgia , Túnica Média/cirurgia , Aorta Torácica/patologia , Suínos , Túnica Média/patologiaRESUMO
OBJECTIVE: To investigate the risk profile of patients with thrombosis and emboli, and prognostic factors for death or amputation in patients presenting with acute limb ischemia in a tertiary care regional hospital in Brazil. METHODS: A prospectively planned cohort study was carried out in which 83 patients with acute limb ischemia, secondary to thrombosis, or embolism, classified in stages II and III of severity were evaluated. Univariate analysis and logistic regression models were used to explore the relationship between anthropometric and demographic characteristics, comorbidities, cardiovascular risk factors, duration of occlusion, and type of surgery with the incidence of amputation or death, which were evaluated in 30 days and 1 year thereafter. RESULTS: Male gender, smoking, and comorbidities were more frequent among patients with thrombosis, and atrial fibrillation was more common among patients with embolism. Occlusion longer than 24 hours (odds ratio [OR] 2.6, 95% confidence interval [CI] 1.1-7.6) and a trend for diabetes (RR 2.6, 95% CI 0.9-7.5) were the characteristics associated with death or amputation in the multivariate analysis, which occurred in 15 (18.1%) and 24 (28.9%) of the participants, respectively. Reperfusion injury was a risk factor for death but not for amputation (OR 16.9, 95% CI 1.1-232.9) after adjustment for age, duration of occlusion, and diabetes. CONCLUSIONS: Traditional and avoidable risk factors explain the occurrence of thrombosis and embolism in our region. Access to medical care is the most important and modifiable prognostic factor for death or amputation.