A constitutive model for developing blood clots with various compositions and their nonlinear viscoelastic behavior.

Thomas H S Van Kempen,Gerrit W M Peters,Wouter P Donders,Frans N Van De Vosse

doi:10.1007/s10237-015-0686-9

Abstract

The mechanical properties determine to a large extent the functioning of a blood clot. These properties depend on the composition of the clot and have been related to many diseases. However, the various involved components and their complex interactions make it difficult at this stage to fully understand and predict properties as a function of the components. Therefore, in this study, a constitutive model is developed that describes the viscoelastic behavior of blood clots with various compositions. Hereto, clots are formed from whole blood, platelet-rich plasma and platelet-poor plasma to study the influence of red blood cells, platelets and fibrin, respectively. Rheological experiments are performed to probe the mechanical behavior of the clots during their formation. The nonlinear viscoelastic behavior of the mature clots is characterized using a large amplitude oscillatory shear deformation. The model is based on a generalized Maxwell model that accurately describes the results for the different rheological experiments by making the moduli and viscosities a function of time and the past and current deformation. Using the same model with different parameter values enables a description of clots with different compositions. A sensitivity analysis is applied to study the influence of parameter variations on the model output. The relative simplicity and flexibility make the model suitable for numerical simulations of blood clots and other materials showing similar behavior.Electronic supplementary materialThe online version of this article (doi:10.1007/s10237-015-0686-9) contains supplementary material, which is available to authorized users.

Highlights

Blood clot formation is the main process that prevents blood loss after a vascular injury
For clots formed from platelet-rich plasma (PRP), the mean values of the moduli are slightly higher than for those formed from whole blood (WB), while the values for clots formed from platelet-poor plasma (PPP) are much lower than for those of WB and PRP
The rheological results show that the stiffness of clots formed from WB is slightly lower than of those formed from PRP, while those formed from PPP have a much lower stiffness (Fig. 3)

Summary

Introduction

Blood clot formation is the main process that prevents blood loss after a vascular injury. A clot that closes the injury insufficiently leads to excessive bleeding. This shows that the mechanical properties of the blood clot are a major factor for its functioning (Jackson 2011; Tran et al 2013). The mechanical properties of the blood clot are determined by its structural composition (Jen and McIntire 1982; Shah and Janmey 1997; Gersh et al 2009; Undas and Ariëns 2011). Clot formation starts when the injured vessel wall or another thrombogenic surface activates platelets present in the blood. The activated platelets form a plug that provisionally closes the injury (de Groot et al 2012). Red blood cells that occupy about 45 % of the blood volume become entrapped in the clot (Gersh et al 2009)

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