The findings supported the use of brachial-basilic arteriovenous fistulas early and prior to using prosthetic grafts where access was difficult, but the conclusions were limited by small sample sizes, heterogeneity and the lack of randomised trials. Given the lack of high-quality evidence, the authors' cautious conclusions are justified.

To compare the effectiveness of transposed brachial-basilic arteriovenous fistulas (BBAVF) with upper limb arteriovenous prosthetic grafts.

MEDLINE and Scopus were searched until February 2008 for articles written in English or with abstracts in English. Search terms were reported. The references of identified articles were searched.

Studies were eligible for inclusion if they compared the effects of BBAVF with prosthetic arteriovenous upper limb grafts on at least one outcome measure of primary and secondary access patency, as specified in the standards for reports dealing with arteriovenous haemodialysis access by Sidawy et al. (2002, see Other Publications of Related Interest). Studies had a follow-up of at least one year.

Included studies compared BBAVF with polytetrafluoroethylene (PTFE) grafts in the forearm or upper arm or Vectra grafts in the upper arm. Outcomes were primary and secondary failure rates and one year patency rates. Follow-up ranged from 12 months to 60 months.

The authors did not state how the studies were selected for the review or how many reviewers performed the selection.

The methodological quality of the included studies was determined using the Newcastle Ottawa Scale, which assesses the selection of the study group, the comparability of the groups and the evaluation of the outcomes, to a maximum score of nine stars.

The authors did not state how many reviewers performed the validity assessment.

One year patency rates were converted into a dichotomous outcome, of patent or thrombosed, and extracted for each group. Primary and secondary failure rates were also extracted. An odds ratio (OR) with 95% confidence interval (CI) was calculated for each outcome.

Two reviewers independently extracted the data for the review.

Pooled ORs with 95% CIs were calculated for each outcome using a random-effects model in the presence of significant statistical heterogeneity and a fixed-effect model where no significant statistical heterogeneity was detected. Statistical heterogeneity was assessed using the χ² statistic and quantified using the I² statistic. Subgroup analyses were performed separately for upper arm grafts and forearm grafts.

Eleven studies were included in the review (n=1,509 patients); one randomised controlled trial (RCT, n=101), one controlled comparative trial (n=116), and nine retrospective studies (n=1,292). Four studies scored seven or more stars in the validity assessment, five scored five or six stars and two scored less than five stars.

There was no significant difference between BBAVF and prosthetic upper limb arteriovenous grafts in primary failure rates (11 studies, n=1,509; OR 0.67, 95% CI 0.41 to 1.09) nor secondary failure rates (10 studies, n=1,439; OR 0.88, 95% CI 0.69 to 1.12). There was evidence of significant statistical heterogeneity for primary failure rates (p<0.00001), but not for secondary failure rates. There was a higher re-intervention rate with prosthetic upper limb arteriovenous grafts compared with BBAVF (1.32 per graft with prosthetic arteriovenous grafts and 0.54 with BBAVF).

Subgroup analysis revealed that BBAVF was associated with a significant reduction in the risk of primary failure (two studies, n=207; OR 0.30, 95% CI 0.15 to 0.58), but not secondary failure compared with prosthetic forearm grafts. There was no evidence of significant statistical heterogeneity. There was no significant difference between BBAVF and prosthetic upper arm grafts in primary and secondary failure rates.

These findings supported the use of BBAVF early and prior to using prosthetic grafts where access was difficult, but the conclusions were limited by small sample sizes, heterogeneity and the lack of randomised trials.

This review addressed a clear question with well-defined inclusion criteria for the intervention, but the inclusion criteria for study design, participants and outcomes were less clear. Only two databases were searched and relevant data may have been missed. Language restrictions were imposed and no attempt appears to have been made to identify unpublished data, which means the possibility of language or publication bias cannot be ruled out. Appropriate steps were taken to minimise the risk of reviewer error and bias in the data extraction process. It was unclear whether similar steps were taken in the validity assessment and study selection stages and the possibility of reviewer error and bias cannot be ruled out. A validity assessment was carried out, but the majority of studies were retrospective in design and were of low or moderate quality.

Given the lack of high-quality evidence, the authors' cautious conclusions are justified.

Practice: The authors stated that their findings indicate that access should be attempted first using BBAVF rather than forearm grafts.

Research: The authors stated that further randomised controlled trials are needed comparing BBAVF and prosthetic upper limb arteriovenous grafts.

Not stated

Sidawy AN, Gray R, Besarab A, Henry M, Ascher E, Silva M, et al. Recommended standards for reports dealing with arteriovenous hemodialysis accesses. Journal of Vascular Surgery 2002; 35: 603-610.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.