RESUMO
The purpose of this study was to investigate whether there is a risk of thrombosis in the temporary arteriovenous shunt loop (TAVSL). The authors established a TAVSL model in the rabbit. Experimental groups were divided into non-heparin treated and heparin treated. The maximum blood flow volume, blood viscosity, and radius of curvature were measured, and the Reynolds number and the sheer stress were calculated. Computational fluid dynamics (CFD) was used to predict the flow pattern in the TAVSL, and these predicted data were compared with histological results. Early occlusion was noted in 70% (7/10) of the non-heparin-treated group and 22% (2/9) of the heparin-treated group. CFD analysis predicted a high shear stress at the arterial anastomosis region and the outer luminal surface of the curved section. The intimal structure at the luminal surface of the curved section was extensively lost histologically. In the patent group, severe stenosis of the lumen was noted at the apex of the loop due to an organized thrombus. Thus, thrombosis is likely to occur in the TAVSL due to endothelium injury caused by high shear stress, and this results in the formation of white thrombi at an early stage and an organized thrombus at a late stage.
Assuntos
Derivação Arteriovenosa Cirúrgica , Endotélio Vascular/fisiopatologia , Artéria Femoral/fisiopatologia , Hemodinâmica/fisiologia , Trombose/etiologia , Animais , Derivação Arteriovenosa Cirúrgica/efeitos adversos , Velocidade do Fluxo Sanguíneo , Viscosidade Sanguínea , Heparina/farmacologia , Masculino , Coelhos , Fatores de Risco , Estresse Mecânico , Grau de Desobstrução VascularRESUMO
We present the case of a 67-year-old woman with scleroderma who had progressive necrosis of the finger together with severe pain 20 years after harvesting of a radial forearm flap. After reconstruction of the radial artery the ulceration of her right middle finger healed spontaneously within a month, and the pain disappeared.