Steal syndrome

Percutaneous endovascular arteriovenous fistula (endoAVF) procedures carry a lower risk of certain complications than surgical arteriovenous fistula (sAVF) creation, a new study has suggested. Published in the Journal of Vascular Surgery (JVS), the review of existing data on the two approaches examines whether endoAVF improves on sAVF’s patency and complication rates.

Beginning by outlining the “numerous complications and modest patency rates” of sAVF, which they note has “served for decades as the preferred method” for vascular access for haemodialysis, the study authors, led by Alkis Bontinis (AHEPA University Hospital, Thessaloniki, Greece), then turn their attention to endoAVF. They cite results of other recent studies stat ing that endoAVF may improve outcomes, but are keen to point out that those studies are limited by their number of included patients.

The study authors have sought to build on these investigations with a systematic review and aggregated data meta-analysis of 17 endoAVF and sAVF studies. Some 1,118 endoAVFs were considered in this analysis. Studies were considered for relevance before their data were used according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Primary endpoints were primary and secondary patency at a maximum follow-up of one year after the procedures. For the primary endpoint, the authors say they “failed to identify statistically significant differences between sAVF and endoAVF”. Randomised controlled trials as well as “prospective and retrospective data depicting endoAVF creation” were included.

The secondary endpoints included reintervention at the end of follow-up, technical success and incidence of major complications. Steal syndrome and wound infection are two of the complications most associated with AVF procedures—and the study authors’ comparison of sAVF and endoAVF finds that there was “an almost sixfold increased risk for steal syndrome occurrence” when a fistula is created surgically instead of percutaneously. EndoAVF showed a lower rate of wound infection, risk ratio (RR) 4.19 (95% [confidence interval] CI: 1.04-16.88).

The researchers suggest that it is endoAVF’s standardisation of the size of the fistula that accounts for these differences, contrasting with sAVF’s reliance on “the surgeon’s subjective perception” of appropriate size. SAVF also demonstrated low primary patency rates and a higher rate of reintervention. The primary endpoints did not show statistically significant differences between the two types.

Three studies examined by Bontinis et al, including 314 patients, reported technical success rates regarding endoAVF and sAVF “with a pooled odds ratio (OR) of 2.68 (95% CI:0.51-13.97) (I2=0%, p=0.66) favouring sAVF”. Two studies compared the procedures for reintervention rates, “producing an incidence rate ratio (IRR) of 1.28 (95% CI:0.94-1.75) (I2=0%, p=0.85) favouring surgery”.

The statistically insignificant primary patency superiority of sAVF in this analysis may be attributable, they suggest, to “the high percentage of distal (brachiocephalic) AVFs which comprised 48.3% (253/524) of the total population in the sAVF”. They note that the majority of the study population who received endoAVF did so in the proximal forearm, pointing to other studies suggesting that these yield inferior outcomes compared to brachiocephalic AVF creation.

The medium quality of the studies used in the authors’ meta-analysis is described as a limitation. Others included the use of retrospective studies and the fact that only five of the total 18 analysed directly compared the two procedures. The authors also note that “the high heterogeneity presented in our results reflects variation in surgical strategies, anatomic locations, learning curve requirements and individual surgeons’ abilities.”