Approach to a Patient with Non-maturing AV Fistula
Autogenous arteriovenous fistulas (AVFs) are considered the most reliable long-term vascular access in patients undergoing hemodialysis. There has been increase in the AVF creation in patients with end-stage renal disease (ESRD) after implementation of Fi
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13
Ravish Shah and Anil K. Agarwal
13.1
Introduction
The superiority of the native arteriovenous fistula (AVF) over other types of accesses including arteriovenous graft (AVG) and tunneled dialysis catheters (TDC) for chronic hemodialysis is a well-recognized fact. It has been shown to have superior patency rates and lower complication rate including a low risk of infection and a lower intervention rate to maintain its patency [1, 2]. This is the core reason underlying the development of guidelines and the Fistula First project that have led to AVF creation in a majority of patients with end-stage renal disease (ESRD). Unfortunately, a considerable number of fistulas (28–53 %) fail to mature sufficiently to support dialysis therapy [3–6]. Failure to mature (FTM) often commits these patients to a tunneled dialysis catheter for a variable length of time until they have a well-functioning arteriovenous (AV) access [3]. In addition to the risk of infection and central venous stenosis, the catheters also contribute to inadequate dialysis and poor patient outcomes [3]. Therefore, early recognition and timely intervention in cases of an AVF with FTM are critically important [3].
13.1.1 Failure to Mature: Definition Fistula failure can be classified as early and late. Early failure is a true FTM that refers to the cases in which the AV fistula never develops to the point that it can be used or fails within the first 3 months of usage [1]. Late failure refers to those cases where the AVF fails after 3 months of successful usage [7, 8]. Although there might be considerable overlap in the causes of both early and late failure, early failure has gained significant attention as recent data have demonstrated that a great majority of the failed fistulas can be salvaged R. Shah, MD • A.K. Agarwal, MD, FACP, FASN, FNKF (*) Division of Nephrology, The Ohio State University, 395 W 12th Avenue, Ground Floor, Columbus, OH 43210, USA e-mail: [email protected]
using percutaneous interventions [9–12]. While it not infrequent to abandon these AVFs with early failure, aggressive evaluation and treatment have been shown to result in the salvage of vast majority of these accesses [10].
13.1.2
Risk Factors for Failure of Maturation
FTM is a common problem occurring in 28–53 % of native AVF [3–6, 13]. Several studies have looked at factors that might predict fistula maturation. Preoperative vascular mapping has been shown to improve the rate of fistula placement and overall surgical success rate [14–16]. Creation of AVF using very small arteries (e.g., < 1.6 mm in diameter) and veins is likely to fail, although the precise cutoff hinges on the available surgical experience and expertise [14]. Perhaps the most critical determinant of fistula maturation is the functional ability of the artery and vein to dilate and achieve a rapid increase in blood flow after surgery [14]. Several studies have shown that postoperative flow rate measured by Doppler ultrasound in a forearm fistula is a moderately good predictor of fistula maturation [
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