Access timing in hemodialysis
There are two types of arteriovenous accesses (AVA) for hemodialysis (HD) patients: “permanent” ones, i.e. arteriovenous fistulas (AVF) and arteriovenous grafts (AVG), or “temporary” ones, i.e. tunneled central venous catheters (TCVC).
However, not enough is known about what effects the sequence in which permanent accesses are placed or used has on access durability or patient outcomes, say nephrologists at the Wake Forest School of Medicine in North Carolina (USA) (Murea M et al, Vascular Access Placement Order and Outcomes in Hemodialysis Patients: A Longitudinal Study. Am J Nephrol. 2017;46:268-2).
The current study pursued these questions and found as main results that the sequence of placement does indeed affect the outcomes of HD vascular access, and that only half of patients effectively achieve a “permanent” vascular access.
The authors included close to 400 patients initiating chronic HD via a TCVC, and recorded chronological distributions of HD vascular accesses over 2.8 years. The distributions were grouped into periods for TCVC-delivered and AVA-delivered (AVF or AVG) HD.
The authors then evaluated primary AVA failure and cumulative access survival based on access placement sequence and type.
92.3 percent of patients underwent a total of 497 AVA placement surgeries.
Primary AVF failure rates increased with each successive fistula placement (p = 0.008).
Of the 82.9 percent (324/391) of TCVC patients who successfully converted to an AVA, 30.9 percent returned to a TCVC, followed by a 58.0 percent conversion rate to another AVA.
Comparing the first AVA with the second AVA, cumulative access survivals were 701.0 vs. 426.5 days, respectively.
52.2 percent of patients subsequently converted from a TCVC to a permanent access and received HD via AVA for ≥ 80 percent of treatments.
The sequence in which HD vascular accesses are placed influenced the outcomes of HD patients, conclude the authors. A further conclusion: Only half of AVA patients effectively achieved a “permanent” vascular access and used an AVA for the majority of HD treatments.
Link to the study: https://www.karger.com/Article/Abstract/481313