Investigating the Influence of Red Blood Cell Heterogeneity on Cell Transport and Blood Flow Hemodynamics

Red blood cell distribution width (RDW), a routinely measured biomarker of red blood cell (RBC) size heterogeneity, is strongly associated with cardiovascular events, cancer progression, and mortality. However, its mechanistic role remains poorly understood due to limited experimental control and the computational difficulty in modeling heterogeneous cell populations. Therefore, we develop and verify a high-resolution, massively parallel computational framework that explicitly models physiologically relevant RDW levels and quantifies their impact on blood flow and cell transport. Using large-scale parallel simulations across representative vascular geometries, including straight vessels, bifurcations, stenoses, and expansions, we show that bulk hemodynamics are largely insensitive to RDW variation, whereas RBC transport and circulating tumor cell (CTC) margination are strongly affected. These results highlight the importance of RBC heterogeneity in cell-level transport modeling and provide mechanistic insight into the links between RDW and disease risk. Our framework enables the scalable incorporation of patient-specific RDW into predictive simulations, supporting precision modeling in cardiovascular and oncological applications.