PB0523 - Effect of Flow on Structural and Mechanical Properties of the Fibrin Network in Plasma Thrombi

Background: The fibrin network is one of the main components of thrombi. Altered network properties are known to influence the development and progression of thrombotic disorders, at least partly through effects on the mechanical and lytic stability of fibrin. Most studies investigating the role of fibrin in thrombus behavior prepare clots under static conditions, missing the influence of blood flow which is present in vivo.

Aims: To study the effect of fluid flow on the structural and mechanical properties of the fibrin network.

Methods: Plasma thrombi in the presence and absence of fluid flow were prepared inside a Chandler Loop. Recitrated plasma (PPP) from healthy donors were spun at 0 and 30 RPM. Six thrombi were formed under each flow condition and studied using SEM (Scanning Electron Microscopy), confocal microscopy and unconfined compression testing. We quantified fibrin fiber density, pore size, and fiber thickness and bulk stiffness at low and high strain values.

Results: Fibrin fibers were thicker in the thrombi formed under flow compared to static thrombi. Fibrin network density increased while the pore size decreased in the presence of flow. Compression testing showed an increased stiffness for clots formed at 30 RPM compared to static clots.

Conclusion(s): Presence of flow strongly influenced the structural and mechanical properties of clots formed under flow, creating denser and more rigid clots. Possibly indicating that fluid flow is an essential factor in determining the behavior of blood clots in vivo and therefore should be considered when developing physiologically relevant models of blood clots.