Medical adjuvant treatment to increase patency of arteriovenous fistulae and grafts
Abstract
Background
End‐stage renal disease (ESRD) patients often require either the formation of an arteriovenous (A‐V) fistula or an A‐V interposition prosthetic shunt for haemodialysis.
Objectives
To determine the effects of adjuvant drug treatment on the patency of fistulae and grafts in patients with ESRD who are undergoing haemodialysis by assessing the number of thrombotic episodes.
Search methods
The Cochrane Peripheral Vascular Diseases Group (PVD) searched their Specialised Register (last searched May 2008) and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, Issue 2).
Selection criteria
RCTs of active drug versus placebo in patients with ESRD undergoing haemodialysis via an A‐V fistula or prosthetic interposition A‐V graft.
Data collection and analysis
For the update, two review authors (ADS, GO) independently assessed trial quality and ADS, XE, and GO extracted data. Information on adverse events was collected from the trials. The outcome measure analysed was the long‐term fistula or graft patency rate.
Main results
The overall results of the meta‐analysis (three RCTs) comparing aspirin versus placebo favoured treatment with aspirin (odds ratio (OR) 0.42, 95% confidence interval (CI) 0.20 to 0.86; P = 0.02).
The overall result of the meta‐analysis ( three RCTs) comparing ticlopidine (a platelet aggregation inhibitor) versus placebo favoured active treatment (OR 0.47, 95% CI 0.26 to 0.85; P = 0.01).
The overall result from one trial comparing the effect of dipyridamole versus placebo and dipyridamole plus aspirin versus placebo favoured treatment (OR 0.57, 95% CI 0.13 to 2.51; OR 0.77, CI 0.19 to 3.19, respectively).
One trial compared fish oil (4 g/daily) versus placebo with 24 participants, follow‐up 12 months. The overall result favoured treatment (OR 0.07, 95% CI 0.01 to 0.49).
One trial compared low‐dose warfarin with placebo, 107 patients were followed for 37 months but the trial was terminated prematurely due to increased bleeding events in the treatment group. The overall result favoured placebo (OR 1.76, 95% CI 0.78 to 3.99).
One trial compared sulfinpyrazone versus placebo. Sixteen patients, follow‐up three months, and the overall result favoured treatment (OR 0.14, 95% CI 0.01 to 1.99).
Finally, one trial compared clopidogrel (75 mg/once daily) with placebo. Twenty‐four patients, follow‐up over a three‐year period until their first episode of thrombosis. The overall result favoured treatment (OR 0.01, 95% CI 0.00 to 0.15).
Authors' conclusions
The meta‐analysis confirmed the beneficial effect of anti‐platelet treatment as an adjuvant used to increase the patency of A‐V fistulae and grafts in the short term.
PICOs
Plain language summary
Medical adjuvant treatment to increase the patency of arteriovenous fistulae and grafts used for renal dialysis
People with advanced kidney disease (end‐stage renal disease) need dialysis to perform kidney functions. In haemodialysis, blood is filtered through a machine. To allow a large enough passage for blood to flow between the person and the machine, an artery and a vein can be surgically joined (to form an arteriovenous fistula) or an artificial graft (a substitute for a vein) is used to join the artery to the vein. These access points might last for years but can become blocked or infected. The review of trials found that anti‐clotting drugs (anti‐platelet drugs like aspirin) can keep these dialysis access points clear, at least in the short term. The review authors found ten randomised controlled trials of anti‐platelet drugs such as ticlodipine, aspirin, dipyridimole and clopidogrel or anti‐thrombotic and other drug treatment used to prevent blockages in the artery and vein access points for dialysis. Three trials of aspirin that involved a total of 173 participants gave an overall result favouring treatment. The follow‐up time and the dosage of aspirin (325 mg/once daily; 500 mg/once daily; and 160 mg/once daily) were different in each of the trials. In three trials with a total 312 participants, ticlopidine (250 mg/twice daily) improved patency at one month compared with placebo (OR for loss of patency 0.47, range 0.26 to 0.85). Single trials involving from 16 to 36 participants compared dipyridimole, fish oil (4 g/daily), clopidogrel (75 mg/once daily) or sulfinpyrazone (a uricosuric drug) with placebo. Although the results favoured treatment the trials were small and single trials are insufficient to recommend use. One trial compared low dose warfarin with placebo. A total of 107 patients were followed for 37 months before the trial was terminated early because of major bleeding events in the treatment group. Some of the trials were from the 1970s and 80s. Most had a short follow‐up period so that any benefits in the longer term are not clear. Information given on complications of the treatments was limited.
