Failure of hemodialysis access is caused mostly by venous intimal hyperplasia, a fibro-
muscular thickening of the vessel wall. The pathogenesis of venous neointimal hyperplasia
in primary arteriovenous fistulae consists of processes that have been identified as upstream
and downstream events. Upstream events are the initial events producing injury of the
endothelial layer (surgical trauma, hemodynamic shear stress, vessel wall injury due to
needle punctures, etc.). Downstream events are the responses of the vascular wall at the …