Effect of Clopidogrel on Early Failure of Arteriovenous Fistulas for Hemodialysis (FISTULA)

General Description

The Dialysis Access Consortium (DAC) was developed to investigate interventions to improve hemodialysis vascular access outcomes in patients with end-stage renal disease (ESRD). The Clopidogrel Prevention of Early AV Fistula Thrombosis (FISTULA) study was one of two major clinical trials conducted under the DAC. The study was a randomized, double-blind, placebo-controlled trial of clopidogrel administered following fistula creation in a large group of patients with advanced chronic kidney disease or ESRD. The arteriovenous fistula is the preferred type of vascular access for hemodialysis because of lower thrombosis and infection rates and lower health care expenditures compared with synthetic grafts or central venous catheters; however, early failure of fistulas due to thrombosis or inadequate maturation is a barrier to increasing the prevalence of fistulas among patients treated with hemodialysis. The FISTULA study aimed to investigate the ability of platelet inhibition to prevent early fistula failure and increase the number of fistulas that ultimately become usable for hemodialysis access.

Participants with chronic kidney disease or ESRD who underwent creation of a new native arteriovenous (AV) fistula were randomized to treatment with clopidogrel or placebo for six weeks following fistula creation surgery. The primary outcome was fistula thrombosis, determined by physical examination at 6 weeks. The secondary outcome was failure of the fistula to become suitable for dialysis. The study found that clopidogrel reduces the frequency of early thrombosis of new arteriovenous fistulas but does not increase the proportion of fistulas that become suitable for dialysis.

Objectives

The FISTULA study sought to determine whether clopidogrel had an effect on early fistula failure and could increase the number of fistulas that ultimately become useable for hemodialysis in patients with chronic kidney disease or ESRD.

Outcome Measure

The primary outcome was fistula thrombosis, determined by physical examination at 6 weeks. The secondary outcome was failure of the fistula to become suitable for dialysis. Suitability was defined as use of the fistula at a dialysis machine blood pump rate of 300 mL/min or more during 8 of 12 dialysis sessions.

Criteria

Participants who met the following criteria were enrolled:

• Life expectancy of at least six months

• Chronic renal failure with anticipated start of hemodialysis within six months of enrollment, or current dialysis dependence

• Planned creation of native upper extremity AV fistula

• Either (1) not on aspirin or (2) on aspirin but without a myocardial infarction or a cerebrovascular accident within the past 12 months

The exclusion criteria are documented in the study protocol.

Outcome

The study found that clopidogrel reduces the incidence of early thrombosis of new arteriovenous fistulas but does not increase the proportion that become suitable for dialysis.