ABSTRACT
FUNDAMENTO: Otimização da veia safena na revascularização miocárdica. OBJETIVO: Apresentar a técnica no-touch de preparo da veia safena. Essa técnica consiste na retirada da veia safena do seu leito, com um pedículo de tecido adiposo, protegendo-a contra espasmos, sendo desnecessário distendê-la. MÉTODOS: Estudo prospectivo e randomizado, incluindo 156 pacientes submetidos a cirurgia de revascularização miocárdica. Comparação da técnica no-touch com duas outras técnicas: convencional e intermediária. Procedeu-se à avaliação da morfologia endotelial, utilizando a microscopia. A perviabilidade das pontes foi determinada com exame angiográfico num período médio de 18 meses após a operação. A enzima óxido nítrico sintetase endotelial (eNOS) foi identificada por meio do estudo imunohistoquímico. RESULTADOS: A avaliação morfológica mostrou integridade endotelial de 97 por cento nas veias do grupo no-touch; enquanto quase metade da superfície endotelial das veias tratadas pelas outras técnicas exibiu ausência de células endoteliais. A angiografia revelou perviabilidade de 95,4 por cento para as pontes do grupo no-touch, 88,9 e 86,2 por cento para as pontes do grupo convencional e intermediária, respectivamente. O estudo imunohistoquímico revelou a presença da eNOS nas três camadas que compõem a parede da veia no grupo no-touch e redução dessa enzima no grupo convencional. CONCLUSÃO: A integridade endotelial e a atividade da eNOS foram melhor preservadas com o uso da técnica no-touch. A proteção mecânica fornecida pelo tecido gorduroso circundante à veia e a atividade vasodilatadora e bloqueadora da agregação plaquetária causada pelo óxido nítrico podem ser responsáveis pela proteção da veia contra o espasmo, como também por sua alta perviabilidade imediata.
BACKGROUND: Optimization of the saphenous vein for myocardial revascularization. OBJECTIVE: To present the no-touch technique of the saphenous vein preparation. This technique consists of harvesting the vein with a pedicle of surrounding tissue, which protects the vein from spasms, obviating the need for distension. METHODS: A prospective, randomized study with 156 patients who underwent artery bypass grafting was performed comparing three saphenous vein harvesting techniques: conventional, intermediate, and no-touch. A morphological study of the endothelium was carried out using scanning microscopy. An angiographic assessment of the vein graft patency was performed at a mean follow-up time of 18 months. Also, an immunohistochemical assessment was carried out to identify the endothelial enzyme nitric oxide synthase (eNOS) in the vein wall RESULTS: The preservation of the endothelial cell integrity was greater in the no-touch technique than in the other procedures. At angiographic follow-up, the patency for the no-touch group was 95.4 percent, 88.9 percent for the grafts of the conventional technique group, and 86.2 percent for the grafts performed in the intermediate technique group. The immunohistochemical assessment revealed eNOS in all three layers of the vein wall in the no-touch group and reduction of this enzyme in the conventional group. CONCLUSION: The endothelial integrity and eNOS activity were better preserved when using the no-touch technique for vein graft harvesting. The mechanical protection provided by the cushion of surrounding tissue in the no-touch group, the vasorelaxation and thromboresistant activities of nitric oxide may be responsible for the reduction of vasospasms and improved patency rate.
Subject(s)
Aged , Female , Humans , Male , Middle Aged , Coronary Artery Bypass/methods , Endothelium, Vascular/ultrastructure , Nitric Oxide/metabolism , Saphenous Vein/transplantation , Tissue and Organ Harvesting/methods , Vascular Patency/physiology , Coronary Angiography , Coronary Artery Bypass/instrumentation , Follow-Up Studies , Graft Occlusion, Vascular , NADPH Dehydrogenase/metabolism , Nitric Oxide Synthase Type III/metabolism , Nitric Oxide Synthase/metabolism , Prospective Studies , Statistics, Nonparametric , Saphenous Vein/enzymologyABSTRACT
Segments of internal mammary arteries and saphenous veins and cultured smooth muscle cells were incubated with and without doxycicline. Metalloproteinases activity was assessed by zymography and Western Blot. Activity of Metalloproteinase-9 in saphenous veins was 217 percent less than in internal mammary arteries. In these vessels doxycicline decreased metalloproteinase-9 activity by 207 percent and metalloproteinase-1 expression. In cultured smooth muscle cells, the median inhibitory concentration of doxycicline for metalloproteinase-2 was 138 uM (r2=0.82). Internal mammary arteries and saphenous veins have different metalloproteinase activities, that are inhibited by doxycicline