Evaluation of the LGM Vena-Tech Infrarenal Vena Cava Filter in an Ovine Venous Thromboembolism Model

Experimental study and constitutive modelling of the passive mechanical properties of the ovine infrarenal vena cava tissue

“…Following histo-mechanical observations, two anisotropy directionscorresponding to the longitudinal and circumferential directionswere assumed in order to handle anisotropy in the models. The varying composition of the vena cava resulted in marked inter-individual geometrical (Canham et al, 1997;Crochet et al, 2001) and longitudinal stretch (Weizsä cker, 1988) variabilities (see Tables 1 and 2 Xie et al (1991) (1.63 [-] for the thoracic portion, and 1.88 [-] for the abdominal portion) for rats, whereas the total average value (1:72 AE 0:48 [-]) was also comparable to the 1.82 [-] stretch value reported by Weizsä cker (1988) for the rat cava. Concerning the stress-stretch behaviour, tests in different directions clearly showed the anisotropic character of the caval tissue, in agreement with the literature (Sakanishi et al, 1988).…”

“…It occurs when blood clots develop in large veins; these clots can dislodge and move to the lungs or heart where they may cause serious pathologies, such as pulmonary embolism or heart attacks. The standard mechanically based treatment is based on the insertion of an intra-venous filter into the infrarenal section of the vena cava to capture clots (see, e.g., Crochet et al, 2001;Girard et al, 2003). Filters can be permanent or just temporarily inserted into the vein wall and fixed to the vein wall by means of hooks.…”

“…An ovine animal model was chosen because of its similar geometry-thickness and diameter-with human vena cava (Crochet et al, 2001). Residual strains in longitudinal direction were measured and monotonic and cyclic simple tension tests in longitudinal and circumferential directions were performed.…”

Effects of Thrombosed Vena Cava Filters on Blood Flow: Flow Visualization and Numerical Modeling

“…1 Fibrous evolution of trapped thrombus led to the formation of fibrous webs between the wall struts and IVC wall in a follow-up study. 5 In a comparison study of stents implanted in the canine aorta and IVC, medial hyperplasia of the IVC associated with thrombus formation led to incorporation of the stent wires into the vessel wall. 27 In a comparison of the Greenfield and Vena Tech filters performed in sheep, blood clots 5 mm in diameter by 5, 10, and 30 mm long were injected.…”

A New Experimental Porcine Model of Venous Thromboembolism

“…In the mouse model described by Matsuno et al [ 32 ], PE was evoked by continuous induction of thrombus in the left jugular vein via endothelial injury, due to a photochemical reaction. Nonetheless, in the majority of animal models of PE, the thrombus causing this disease was formed outside the animal organism and then injected into the vessel [ 33 , 34 , 35 ]. In the present experiment, we succeeded in introducing the porcine experimental model in which not only both DVT and PE are induced in the same animal but also both these conditions are initiated in vivo.…”