RESUMO Objetivo: Aneurismas dissecantes da aorta envolvendo artérias viscerais são de difícil tratamento clínico. O objetivo deste estudo foi explorar a eficácia e segurança clínica da técnica de stents multicamadas não farmacológicos para o tratamento de aneurismas dissecantes da aorta envolvendo artérias viscerais. Métodos: Foi feito um estudo retrospectivo usando os dados de 16 pacientes com aneurisma dissecante da aorta envolvendo artérias viscerais e tratados com stents multicamadas não farmacológicos de março de 2013 a março de 2017, do Hospital da Escola de Medicina da Universidade de Tianjin. Foram analisados nos 167 pacientes: a eficácia clínica, o número de stents aplicados, trombose dissecante da aorta no pós-operatório e patência cumulativa pós-operatória do ramo arterial. Resultados: As operações dos 16 pacientes foram concluídas com sucesso sem nenhum óbito perioperatório. Os 16 pacientes receberam 39 stents não farmacológicos, com uma média de 2,44 por indivíduo. Houve 2 casos com 1 stent, 8 com 2 stents, e 7 com 3. Um mês após a operação, a ATC mostrou trombose completa da dissecção arterial em 4 casos (25,0%) e trombose parcial em 12 casos (75%). Também mostrou que a artéria celíaca, as artérias renais direita e esquerda e a artéria mesentérica superior estavam todas desobstruídas. Houve 4 casos (25,0%) de artéria dissecante com diâmetro reduzido, 12 (75,0%) pacientes sem alteração no diâmetro, e nenhum caso de aumento de diâmetro. Conclusão: O tratamento para aneurisma dissecante da aorta envolvendo artérias viscerais com a técnica de stents não farmacológicos multicamadas é seguro e confiável, com uma taxa mais alta de patência de ramos arteriais acumulados no pós-operatório.

SUMMARY OBJECTIVE: Aortic dissecting aneurysms involving visceral arteries are difficult for clinical treatment. This study aimed to explore the clinical efficacy and safety of multi-layer bare stents technique in the treatment of aortic dissecting aneurysms involving visceral arteries. METHOD: The clinical data of 16 patients of aortic dissecting aneurysm involving visceral artery treated with multi-layer bare stents technique from March 2013 to March 2017 in Tianjin Medical University General Hospital were retrospectively analyzed. To explore the clinical efficacy, the number of stents applied, postoperative aortic dissecting thrombosis and postoperative cumulative branch arterial patency of the16 patients. RESULTS: The operations of the 16 patients were successfully completed without peri-operative death cases. The 16 patients were implanted with 39 bare stents with an average of 2.44 per person. There were 2 cases with 1 stent, 8 cases with 2 stents and 7 cases with 3 stents. One month after the operation, CTA showed complete thrombosis in the arterial dissection in 4 cases (25.0%), partial thrombosis in 12 cases (75.0%); CTA showed that celiac artery, left and right renal arteries, and superior mesenteric artery were all unobstructed. There were 4 cases (25.0%) of dissecting artery with reduced diameter, 12 patients (75.0%) without changes in the diameter, and no diameter expanding cases. CONCLUSION: The treatment for aortic dissecting aneurysm involving the visceral arteries using multi-layer bare stents technique is safe and reliable with a higher patency rate of postoperative accumulated branch arteries.

Spinel ferrite powder with a nominal composition Ni0.4Zn0.6Fe2O4 was prepared by a hydrothermal method, following by sintering at 700 °C and 900 °C, respectively. The structural and magnetic properties of specimens are studied. It is found that the large particles in specimens are the agglomerates of many small nanoscale crystallites. A strengthening of chemical polarization of the internal chemical bonds is found in the powder specimen after sintering. The saturation magnetization increases from 50.1 emu/g for as-synthesized powder to 63.1 emu/g for specimen sintered at 900 °C mainly due to the weakening of spin canting, while the coercivity exhibits a slight decreasing variation with the increase of sintering temperature.