RBC aggregation: more important than RBC adhesion to endothelial cells as a determinant of in vivo blood flow in health and disease.

Although the shear-dependent and reversible phenomenon of red blood cell (RBC) aggregation has been studied for decades, its role as a determinant of in vivo blood flow in both health and disease has not yet been fully documented. In this brief review, we present compelling arguments, supported by literature evidence, that in vivo flow dynamics are more affected by RBC aggregation than by RBC adhesion to endothelial cells (ECs). A companion article (i.e., a "counter-point") published in this issue of the journal argues that in disease states, RBC-EC adhesion is the more important determinant.