February 2023 Issue 06 www.renalinterventions.net
In this issue:
Cannulation innovation explored page 4
Drug-coated balloon beats plain balloon in ABISS trial perprotocol analysis
Drug-coated balloon disadvantaged? Drawing attention to the difference between the intention-to-treat analysis results and those of the per-protocol analysis, Coscas said that “the way data of the study were analysed will need to be discussed because, in the intention-to-treat analysis, patients lost to follow-up or who waived consent were imputed to the worstcase scenario (loss of patency if in the DCB arm and to patency if in the placebo arm),” suggesting a “disadvantage” for the DCB in the intention-to-treat results. “This was less the case in the per-protocol analysis—I think we will discuss that later on”.
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Dirk Hentschel on wearable dialysis page 9
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Robert Jones page 12
Steal syndrome and wound infection less likely with percutaneously-created arteriovenous fistulas
Data have been presented for the first time at the Paris Vascular Insights (PVI) conference (23–25 November, Paris, France) from the ABISS trial, which compared drug-coated balloon (DCB) with plain-balloon angioplasty for arteriovenous fistula (AVF) stenosis. ABISS WAS A PHYSICIAN-DESIGNED prospective, randomised, double-blind trial that included 12 centres in France. The study enrolled 150 adult patients who had a native autologous AVF stenosis already punctured for haemodialysis. Following predilatation, patients were randomised 1:1 between DCB (Lutonix, BD) and placebo balloon application. The study was mainly funded by the French government clinical research programme (PHRC). The primary outcome of the study was cumulated incidence of loss of primary patency of AVF at six months. The study authors, led by Raphaël Coscas (Ambroise Paré Hospital and Paris-Saclay University, Paris, France) found in an intention-to-treat analysis DCB was superior to plain-balloon angioplasty at six months but not in a statistically significant way, with a p value of 0.09. It was, however, statistically significant at three months (p=0.002). In a prespecified per-protocol analysis, the DCB was superior to a statistically significant degree at the intervals of three (p=0.0004), six (p=0.008), and 12 months (p=0.029) for the main outcome.
Home dialysis in depth
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.
Raphaël Coscas
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eginning 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 stating 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 Alkis Bontinis 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.”