Early Arteriovenous Fistula Failure

Abstract

A significant number of arteriovenous fistulae (28 to 53%) never mature to support dialysis. Often, renal physicians and surgeons wait for up to 6 months and even longer hoping that the arteriovenous fistula (AVF) will eventually grow to support dialysis before declaring that the AVF has failed. In the interim, if dialysis is needed, then a tunneled catheter is inserted, exposing the patient to the morbidity and mortality associated with the use of this device. In general, a blood flow of 500 ml/min and a diameter of at least 4 mm are needed for an AVF to be adequate to support dialysis therapy. In most successful fistulae, these parameters are met within 4 to 6 wk. Most important, commonly encountered problems (stenosis and accessory veins) that result in early AVF failure can be diagnosed easily with skillful physical examination. Recent studies have indicated that a great majority of fistulae that have failed to mature adequately can be salvaged by percutaneous interventions and become available for dialysis. Early intervention regarding identification and salvage of a nonmaturing AVF is critical for several reasons. First, an AVF is the best available type of access regarding complications, costs, morbidity, and mortality. Second, this approach minimizes catheter use and its associated complications. Finally, access stenosis is a progressive process and eventually culminates in complete occlusion, leading to access thrombosis. In this context, the opportunity to salvage the AVF that fails early may be lost. This report reviews the process of AVF maturation and suggests a strategy for when and how to intervene to identify and salvage AVF with early failure.

Arteriovenous Fistula Placement in the Elderly

“…Most experts advocate early placement of AVFs considering that fistulae need about 4-6 weeks to mature for use, 20,21 and there is general consensus of the importance of early referral for pre-ESRD care. [22][23][24][25][26][27] Although many AVFs are created in advance of dialysis initiation, 99% of fistulae were cannulated within 4 months of their creation in the United States.…”

Decreased Cumulative Access Survival in Arteriovenous Fistulas Requiring Interventions to Promote Maturation

“…We continue to believe, however, that a randomized study examining this issue is desperately needed. At present, there are no effective pharmacologic treatments to promote AVF maturation, largely due to our limited understanding of the pathophysiology of AVF maturation (1)(2)(3)17,44,45). In this regard, a large randomized, double-blinded clinical trial found that clopidogrel significantly reduced early AVF thrombosis but failed to decrease AVF nonmaturation (14).…”

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).…”