Fractional AVF diameter change as a function of local adipose mediator levels during each time interval. A significant relationship between the fractional change in diameter and both IL-6 (P = 0.01) and MCP-1 (P = 0.02) was observed during the early phase of fistula maturation. This corresponded to a 7.9% and 12.6% decrease in fistula diameter for every 10 pg IL-6/mg tissue or 10 pg MCP-1/mg tissue increase in IL-6 and MCP-1 levels, respectively. In terms of absolute vein diameter changes, this represented a 0.45-mm and 0.30-mm difference between the 10th and 90th percentiles of IL-6 and MCP-1 concentrations, respectively. AVF, arteriovenous fistula; IL, interleukin; MCP, monocyte chemoattractant protein.