Why don't fistulas mature?

Abstract

Fistula maturation requires a compliant and responsive vasculature capable of dilating in response to the increased velocity of blood flowing into the newly created low-resistance circuit. Successful maturation to a high volume flow circuit capable of sustaining hemodialysis typically occurs within the first few weeks after creation. Failure to achieve maturation within 4-8 weeks should prompt a search for reversible etiologies; however, an accepted definition of maturation, particularly for patients not yet on dialysis remains elusive. The most commonly identified etiology is neointimal hyperplasia typically occurring in the juxta-anastomotic vein. However, failed maturation has also been reported secondary to impaired arterial and venous dilation and accessory veins. The exact frequency of each of these etiologies is unclear. Understanding the etiologies of impaired fistula maturation will focus future studies of targeted interventions to improve the rate of fistula maturation and increase the number of dialysis patients with a functioning autogenous fistula.

Increased Hemodialysis Catheter Use in Canada and Associated Mortality Risk

“…Fistulas that fail to mature (FTM) are increasingly more common with rates between 9% and 70% (18,19) and the highest FTM rates among the elderly, diabetics, and those with vascular disease (19), the same group that represents the largest growth in dialysis. When this early fistula failure is considered in cumulative patency analysis, there is little difference compared with graft patency (20,21).…”

Novel Paradigms for Dialysis Vascular Access

“…The histology of AVF nonmaturation has been demonstrated to be secondary to aggressive venous neointimal hyperplasia ( Figure 2, A and B), with the majority of cells within the neointima staining for myofibroblasts, but with contractile smooth muscle cells and fibroblasts also present (6). In addition to aggressive neointimal hyperplasia development, inadequate vasodilation (inward remodeling), resulting in vasoconstriction of the vein, also likely plays an important role in AVF nonmaturation (7)(8)(9)(10).…”

Suppressing unsteady flow in arterio-venous fistulae

“…A major cause of AVF failure is the formation of stenotic regions due to development of Intimal Hyperplasia (IH) in the juxta-anastomotic area and the vein. 5,7,8 Whilst the exact mechanisms underlying development of IH in AVF are unknown, there is considerable evidence to suggest that their inherently unphysiological flow patterns play an important role. 5,8,9 In particular regions of low Wall Shear Stress (WSS), [9][10][11][12][13] low lumen-to-wall oxygen flux (leading to wall hypoxia) [14][15][16][17] and high-frequency flow unsteadiness [18][19][20][21][22] have all been individually implicated in the initiation and development of IH, although it is of course possible that these factors are related, and a combination is responsible.…”

“…In an ideal scenario, these changes stimulate vascular dilation and re-modeling, such that the AVF "matures," and can be used for haemodialysis. 5 Unfortunately, however, up to 60% of AVF do not mature as anticipated, 6 resulting in unacceptable patient morbidity and a significant burden on healthcare expenditure. A major cause of AVF failure is the formation of stenotic regions due to development of Intimal Hyperplasia (IH) in the juxta-anastomotic area and the vein.…”