Design Optimization of Vena Cava Filters: An Application to Dual Filtration Devices

Abstract

Background: Pulmonary embolism (PE) is a significant medical problem that results in over 300,000 fatalities per year. A common preventative treatment for PE is the insertion of a metallic filter into the inferior vena cava that traps thrombi before they reach the lungs. The goal of this work is to use methods of mathematical modeling and design optimization to determine the configuration of trapped thrombi that minimizes the hemodynamic disruption. The resulting configuration has implications for constructing an optimally designed vena cava filter.Approach: Computational fluid dynamics is coupled with a nonlinear optimization algorithm to determine the optimal configuration of trapped model thrombus in the inferior vena cava. The location and shape of the thrombus are parameterized, and an objective function, based on wall shear stresses, determines the worthiness of a given configuration. The methods are fully automated and demonstrate the capabilities of a design optimization framework that is broadly applicable.Results: Changes to thrombus location and shape alter the velocity contours and wall shear stress profiles significantly. For vena cava filters that trap two thrombi simultaneously, the undesirable flow dynamics past one thrombus can be mitigated by leveraging the flow past the other thrombus. Streamlining the shape of thrombus trapped along the cava wall reduces the disruption to the flow, but increases the area exposed to abnormal wall shear stress. Conclusions:Computer-based design optimization is a useful tool for developing vena cava filters. Characterizing and parameterizing the design requirements and constraints is essential for constructing devices that address clinical complications. In addition, formulating a well-defined objective function that quantifies clinical risks and benefits is needed for designing devices that are clinically viable.

A Computational Method for Predicting Inferior Vena Cava Filter Performance on a Patient-Specific Basis

“…Unlike previous computational studies, which considered blood flow in idealized IVC geometries without IVC-IVC filter interactions [17,5,7,19,20], the present study addresses new aspects of IVC filter placement: 1) the in Keefe B. Manning BIO-13-1517…”

Evaluation of migration forces of a retrievable filter: Experimental setup and finite element study

“…Although only Günther Tulip filter model is studied the role of hook in other IVC filters is similar. Finally, the works of Swaminathan et al [22], Leask et al [27], Stewart et al [23], Singer et al [25,26] and Wang and Singer [24], among other, also suggest that hemodynamic considerations are an important factor in the filter designs. However, to analyze the problem of migration or extraction of the filter, the interaction of the vein with the filter is critical.…”

“…Compared with stents, filters are less documented in literature [20,12,[21][22][23]. Moreover, most of this works are correlated only with clinical results, few of them were focused in the improvement in filter design [24][25][26][27].…”

“…Singer et al [25] and Wand and Singer [24] developed three-dimensional models of the TrapEase and Günther Celect IVC filters with spherical thrombi to evaluate the hemodynamic effects of thrombi, renal vein inflow and filter position. Later, Singer et al [26] used an optimization framework for designing vena cava filters to minimize the hemodynamic disruptions caused by different locations, sizes, and shapes of a model thrombus. However, all these previous models consider only hemodynamic simulations where the wall and the filter are rigid solids, so the interaction between the vein and the filter is not considered.…”

In vitro comparison of Günther Tulip and Celect filters. Testing filtering efficiency and pressure drop

“…Some filter designs are more given to occlude the IVC than others, therefore a good filter design will be able to trap a large amount of clots without impeding the blood flow (Katsamouris et al, 1988;Leask et al, 2004). As stated by Singer et al (2010), from a flow dynamics viewpoint, an optimally designed filter is one that traps thrombus in a configuration that minimises the risk of IVC occlusion. To conclude, filter designs that result in a great increase of pressure after clot entrapment, will have the highest potential for IVC thrombosis.…”