In-vitro Assessments of Clot Elicitation by Thrombogenic Fibers vs. Embolization Coils.

Late and persistent type II endoleaks (EL2) following Endovascular Aneurysm Repair (EVAR) have been recognized as an independent and significant risk factor for aneurysm sac growth and secondary procedures. Solutions are available for treatment, with varying success rates; preventive perioperative sac embolization with coils appears safe and effective. The objective of this study is to compare whole blood coagulation elicited by a textile stent-graft equipped with thrombogenic, patented "Kardiozis" fibers (PKF) to that elicited by embolization coils in an in vitro study. The approach is to establish an equivalence between PKF and coils in a static model, then to compare clot elicitation by both materials in a perfused model aneurysm chamber subjected to EL2. The weight of clot elicited during exposure to blood was the primary measurement. In the static model, PKF and coils were soaked in blood for up to 90 minutes (N = 30) and elicited similar clotting. In the dynamic model, stent-grafts equipped with PKF or coils were exposed to blood flow inside an aneurysm model for up to 3h (N = 5), with generally higher clot weights for stent-grafts with PKF (non-significant). Complete thrombosis of the aneurysm model was observed in one experimental series (positive control and stent-graft with PKF). A stent-graft with PKF elicits at least as much clot as embolization coils dispersed in an aneurysm model chamber under continuous blood flow. PKF positioned on the outer wall of stent-grafts could have a similar action as coiling of the aneurysm sac during the index EVAR.

Deformability- and size-based microcapsule sorting.

Biomedical applications often require to sort cells according to their physical properties, such as size, density or deformability. In recent years, microfluidics has provided a variety of tools to sort micro-objects. We present here a simple microfluidic device consisting of a channel containing a semi-cylindrical obstacle against which capsules are squeezed by the flow, followed by a diverging chamber where streamlines separate. We demonstrate that this basic system is capable of sorting elastic microcapsules according to their size at low flow strength, and according to the stiffness of their membrane at high flow strength. Contrary to most existing sorting devices, we show that the present one is very sensitive and capable of discriminating between capsules with differences in membrane elasticity of order unity.