Blood has complex rheology due to its multi-component structure and physiological processes occurring in it, such as agglomeration and deagglomeration of red blood cells. Furthermore, the risk of red blood cell hemolysis increases as the shear stresses often generated by cholesterol deposits in the arteries increase. To reproduce the physiological behavior of blood, a new blood rheology model was developed, which considers the deagglomeration and agglomeration of red blood cells depending on local shear stresses and the hemolysis of red blood cells caused by high shear stress values. The developed model allows for capturing the thixotropic properties of blood and predicts the physiological size distribution of red blood agglomerates, called Rouleaux. The blood flow curve calculated for viscometric conditions based on the new model was compared with experimental data available in the literature [1]. The model was then applied to arterial blood flow modeling in patients with cardiac diseases. The simulation results for the new rheology model were compared with the Carreau-Yasuda model, where it was shown that the new model better predicts blood viscosities in zones with a sudden increase in stress and beyond this zone, predicting a delay in the viscosity increase related to the need to rebuild the agglomerate structure after passing through a zone of high shear stresses [1]. Moreover, the correctness of the model in predicting hemolysis was checked by comparing the simulation results with literature data. The model has been tested for a wide range of simulations of circulatory system diseases, with an emphasis on atherosclerotic stenosis and aneurysms. ACKNOWLEDGMENTS This research was supported by the PW YOUNG project, granted by the Warsaw University of Technology under the Excellence Initiative: Research University programme. Research was funded by the Warsaw University of Technology within the Excellence Initiative: Research University (IDUB) programme. REFERENCES [1] K. Jędrzejczak, Ł. Makowski, W. Orciuch, Model of blood rheology including hemolysis based on population balance, Commun Nonlinear Sci Numer Simul 116 (2023) 106802. https://doi.org/10.1016/J.CNSNS.2022.106802.