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Design of the Dialysis Access Consortium (DAC) Clopidogrel Prevention of Early AV Fistula Thrombosis Trial
Laura M Dember1, James S Kaufman, Gerald J Beck
1Renal Section, Boston University School of Medicine, MA 02118 USA. ldember@bu.edu
Insights
Clopidogrel may prevent early failure of arteriovenous fistulas used for hemodialysis. This trial
Area of Science:
- Nephrology
- Vascular Surgery
- Clinical Trial Design
Background:
- Autogenous arteriovenous fistulas are recommended for hemodialysis but frequently fail due to post-surgical clotting.
- The Dialysis Access Consortium (DAC) aims to improve hemodialysis vascular access outcomes.
- Early failure of native arteriovenous fistulas is a significant clinical problem.
Purpose of the Study:
- To test if clopidogrel prevents early arteriovenous fistula failure after creation.
- To determine if clopidogrel increases the number of fistulas suitable for hemodialysis access.
- To evaluate pharmacologic interventions for preventing vascular access failure.
Main Methods:
- A multicenter, randomized, double-blind, placebo-controlled trial.
- 1,284 patients undergoing new native arteriovenous fistula creation were enrolled.
- Patients received clopidogrel or placebo for six weeks post-surgery; primary outcome was fistula patency at six weeks.
Main Results:
- The study focused on trial design aspects, including outcome selection and intervention timing.
- Key considerations involved balancing efficacy and safety, ethical drug modifications, and evaluation methods.
- Specific results on clopidogrel's efficacy are detailed in the full study.
Conclusions:
- This is the first large, multicenter trial assessing a pharmacologic approach to prevent early arteriovenous fistula failure.
- The trial provides insights into methodological challenges relevant to future vascular access and clinical trials.
- Findings aim to improve the usability of fistulas for hemodialysis access.
Background:
The Dialysis Access Consortium (DAC) was developed to investigate interventions to improve hemodialysis vascular access outcomes. The autogenous arteriovenous fistula created by direct connection of native artery to vein is the recommended vascular access for hemodialysis. However, it fails frequently due to clotting after surgery.
Purpose:
The DAC Early AV Fistula Thrombosis Trial tests the hypothesis that clopidogrel can prevent early fistula failure and increase the number of fistulas that ultimately become usable for hemodialysis access. This is one of two initial and concurrent trials being performed by the DAC. The companion trial investigates pharmacologic approaches to prevent venous stenosis leading to AV graft failure.
Methods:
This is a multicenter, randomized, double-blind, placebo-controlled trial that will enroll 1,284 patients over four years. Patients undergoing creation of a new native arteriovenous (AV) fistula are randomized to treatment with clopidogrel or placebo for six weeks following fistula creation surgery. The primary outcome is fistula patency at six weeks. The major secondary outcome is fistula suitability for dialysis.
Results:
This paper examines key aspects of this study that have broad relevance to trial design including: 1) the selection of an intermediate event as the primary outcome, 2) timing of the intervention to balance efficacy and safety concerns, 3) ethical considerations arising from required modifications of concomitant drug therapy, and 4) choosing an efficacy or effectiveness evaluation of the intervention.
Conclusions:
This is the first, large, multicenter trial evaluating a pharmacologic approach to prevent early AV fistula failure and promote more usable fistulas for hemodialysis. The methodologic challenges identified and addressed during the development of this trial should help to inform the design of future vascular access trials, and are relevant to clinical trials addressing a wide range of questions.
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