Preliminary report of a new type of braided vein stent in animals

Abstract

Background Iliofemoral vein stenosis or occlusion is a common cause of severe chronic venous insufficiency. Endovascular venous stenting has become a preferred treatment because it is minimally invasive and has a high safety profile. Despite the wide application of the wallstent, it is not specifically designed for veins. There are currently few studies on braided stents in the field of veins. We designed a novel braided vein stent, which has higher radial resistive force and more optimized looped ends structure compared with the wallstent. The purpose of this study was to evaluate the safety and performance of the stent in animals, providing a reference for further clinical trials. Methods The Wallstent is used as a control group. The novel stent and the Wallstent were implanted in the iliac vein of sheep. After 30 days and 90 days, vascular injury, thrombus, neointima coverage, and luminal stenosis were evaluated through venous angiography, endoscopic observation of stent specimen and histopathology. Imaging, histology, and integration data were analyzed by t-test for comparisons between the groups. Results Two groups of stents were successfully implanted. Follow-up observation showed that there was no thrombosis or obstruction >50% occurred in any group and no significant differences in patency, vascular injury, or intimal hyperplasia compared with the Wallstent. Conclusion The novel stent significantly increases the radial resistive force and does not increase vascular injury, thrombus and stent stenosis during 30-day and 90-day follow-up. The next step is to further validate the effectiveness of the stent through long-term animal observation and human clinical trials.

In vivo evaluation of safety and performance of a tapered nitinol venous stent with inclined proximal end in an ovine iliac venous model

“…30 healthy ~ 50 kg sheep were randomly divided into five groups: Day-0 (< 24 h), Day-30, Day-90, Day-180 and Day-360 groups according to the follow-up timepoint. The sample size in each group (timepoint) is consistent with the previous studies by using sheep as the animal model to evaluate the iliac artery or vein stent 8 , 9 . Detailed information of the sheep in each group were shown in Table 1 .…”

“…The efficacy of aspirin and clopidogrel in sheep seems controversial 10 , 11 . But antiplatelet treatment in sheep post stenting were still performed in some recent studies 9 , 12 . Thus, aspirin and clopidogrel were also given to the sheep in this study, with the same of dosage of that in stented patients.…”

Estudo de anatomia comparada suína por angiotomografia: contribuições para modelos de pesquisa e treinamento em cirurgia vascular e endovascular

“…During the bibliographic review, a study describing the development of a novel venous stent employing an ovine animal model was found, which mentioned as a limitation the fact that the stent had been implanted in a vein without stenosis, because of the difficulty of simulating these conditions in animals. 34 This limitation can be potentially overcome by employing pigs, in which venous compression could be detected prior to the experiment with noninvasive examinations, as demonstrated in the present study.…”

“…12,32,33 Porcine models have been employed for development, training, and studies of REBOA. 12,29,32,33 Studies have focused on comparing continuous vs. intermittent [33][34][35] and partial vs. total aortic occlusion, 36 the ideal duration of occlusion, 37 and tissue oxygenation, 38 targeting better results in clinical practice. Our results and the scant published data available suggest that the biological and histochemical repercussions of aortic occlusion in pigs should be judiciously interpreted, since the blood supply to the hind limbs is ensured by anastomoses, such as those between the internal thoracic (mammary) arteries and the epigastric vessels 11 (Figure 4A illustrates the course of the mammary arteries).…”