College of Engineering and Technology, Beijing Institute of Economics and Management, Beijing, 100102, China.
College of Engineering, Peking University, Beijing, 100871, China.
Biomed Eng Online. 2021 Feb 9;20(1):19. doi: 10.1186/s12938-021-00855-x.
Cone-shaped vena cava filters (VCFs) are widely used to treat venous thromboembolism. However, in the long term, the problem of occlusion persists even after the filter is deployed. A previous study hypothesized that the reverse deployment of a cone-shaped VCFs may prevent filter blockage.
To explore this hypothesis, a comparative study of the traditional and reverse deployments of VCFs was conducted using a computational fluid dynamics approach. The distribution of wall shear stress (WSS) and shear stress-related parameters were calculated to evaluate the differences in hemodynamic effects between both conditions. In the animal experiment, we reversely deployed a filter in the vena cava of a goat and analyzed the blood clot distribution in the filter.
The numerical simulation showed that the reverse deployment of a VCF resulted in a slightly higher shear rate on the thrombus, and no reductions in the oscillating shear index (OSI) and relative residence time (RRT) on the vessel wall. Comparing the traditional method with the reversely deployed cases, the shear rate values is 16.49 and 16.48 1/s, respectively; the minimal OSI values are 0.01 and 0.04, respectively; in the vicinity of the VCF, the RRT values are both approximately 5 1/Pa; and the WSS is approximately 0.3 Pa for both cases. Therefore, the reverse deployment of cone-shaped filters is not advantageous when compared with the traditional method in terms of local hemodynamics. However, it is effective in capturing thrombi in the short term, as demonstrated via animal experiments. The reversely deployed cone-shaped filter captured the thrombi at its center in the experiments.
Thus, the reverse deployment of cone-shaped filters is not advantageous when compared with the traditional method in terms of local hemodynamics. Therefore, we would not suggest the reverse deployment of the cone-shaped filter in the vena cava to prevent a potentially fatal pulmonary embolism.
锥形腔静脉滤器（VCF）广泛用于治疗静脉血栓栓塞症。然而，在长期情况下，即使放置了滤器，仍存在阻塞问题。先前的研究假设锥形 VCF 的反向部署可能会防止滤器阻塞。
为了探索这一假设，我们使用计算流体动力学方法对 VCF 的传统和反向部署进行了对比研究。计算了壁面切应力（WSS）和与切应力相关的参数分布，以评估两种情况下血流动力学效应的差异。在动物实验中，我们将滤器反向放置在山羊的腔静脉中，并分析滤器中的血栓分布。
数值模拟表明，VCF 的反向部署会导致血栓上的剪切率略有升高，而血管壁上的振荡剪切指数（OSI）和相对停留时间（RRT）并没有降低。与传统方法相比，反向部署的情况下，剪切率值分别为 16.49 和 16.48 1/s；最小 OSI 值分别为 0.01 和 0.04；在 VCF 附近，RRT 值均约为 5 1/Pa；WSS 对两种情况均约为 0.3 Pa。因此，在局部血流动力学方面，与传统方法相比，锥形滤器的反向部署没有优势。然而，动物实验表明，它在短期内捕获血栓的效果很好。在实验中，反向部署的锥形滤器在其中心捕获了血栓。
因此，在局部血流动力学方面，与传统方法相比，锥形滤器的反向部署没有优势。因此，我们不建议在腔静脉中反向部署锥形滤器来预防潜在致命的肺栓塞。
