Mechanical properties of blood clots – a new test method

Abstract

A blood clot needs to have the right degree of mechanical, chemical and biological properties to stem the flow of blood and yet to be suitable for lytic enzymes or mechanical thrombectomy so as not to form a thrombotic event. The origin and understanding of these mechanical properties are still not known in detail. Clots are made of a three-dimensional network of fibrin fibers stabilized through ligation with a transglutaminase, factor XIIIa. New methods to achieve information about mechanical properties were established in this work. We performed compressive strength experiments of aged human blood clots. Furthermore after the set up of a new test environment, it was possible to perform tensile strength measurements of aged animal blood clots. Stress strain curves of aged clots were measured and discussed. The viscoelastic properties of the clot material were quantitatively described. This work should make a contribution to a better understanding of the behaviour of aged blood thrombus bulk material and induced mechanical stress. Keywords: blood clots / mechanical properties / aging conditions / viscoelastic behaviour /In der Behandlung ischämischer Schlaganfälle sind mechanische, chemische und biologische Eigenschaften von Blutgerinnseln von essentieller Bedeutung und entscheidend über den Erfolg einer Lyse-Therapie bzw. mechanischer Thrombektomie. Die Einflussfaktoren der Gerinnungsbedingungen auf die mechanischen Eigenschaften sind jedoch bisher noch nicht eingehend untersucht. Aus Schrifttum ist bekannt, dass auf mikrostruktureller Ebene die Blutgerinnsel aus Fibrinfasern, die untereinander in Knotenpunkten verbunden sind und in der Gesamtheit ein dreidimensionales Netzwerk bilden, bestehen. Dabei haben besonders die Faserdicke und die Knotenpunktendichte einen direkten Einfluss auf die mechanischen Eigenschaften eines Thrombus. Im Rahmen dieser Arbeit wurden Druck-und Zugversuche an Thrombus-Proben (hergestellt aus humanem bzw. tierischem Blut) durchgeführt und die Messergebnisse hinsichtlich der Gerinnungsbedingungen diskutiert.

Blood clot fracture properties are dependent on red blood cell and fibrin content

“…Therefore an approximate values of = 140, 130, 100 , which are the values of clot stiffness at 75% strain in unconfined compression test, have been used for 5% H, 20% H, and 40% H clots, respectively. In addition, the value of = 10.2 has been taken from Krasokha et al [47].…”

The evolution of manufacturing processes for micro‐featured epoxy resin mold

“…Figure shows the Vickers hardness as a function of ZrO 2 powders. The hardnesses of mold surface increases with increasing the wt% of ZrO 2 powders . It is difficult to add more than 11 wt% of ZrO 2 powders into the epoxy resin composites because ZrO 2 powders and epoxy resin can not be mixed completely.…”

Construction of a comprehensive endovascular test bed for research and device development in mechanical thrombectomy in stroke

“…Manufacturing techniques to generate EAs are available in the literature. 7,[12][13][14] These techniques use animal blood and therefore are not readily available, cause animal discomfort, and/or are expensive. In addition, these EAs made from porcine or bovine whole blood are significantly weaker compared to emboli harvested from LVO strokes: 6 kPa and 30 kPa, respectively, compared to σ ut ranging from 63 to 2396 kPa.…”