A recent network meta-analysis shows that, in failing arteriovenous fistulas (AVFs) with outflow stenosis, drug-coated balloon (DCB) angioplasty is “significantly superior” to plain balloon angioplasty, presenting an improved six-month failure rate. However, Gregory Tripsianis (Democritus University, Alexandroupolis, Greece) and colleagues stress that the effectiveness of DCB angioplasty in the long term “deserves further investigation”.
While the 2018 European Society for Vascular Surgery (ESVS) vascular access clinical practice guidelines recommend balloon angioplasty for the treatment of venous outflow stenosis to extend the use of AVFs, the authors note that its effectiveness compared to other endovascular modalities “remains unclear”. In fact, they state more generally that “there is currently uncertainty regarding the ideal treatment to salvage failing AVFs”.
Writing in an online Journal of Vascular Surgery (JVS) article, Tripsianis et al note that it was their intention in this study to investigate the comparative effectiveness of the different endovascular treatments in patients with failing autogenous AVFs with outflow vein stenosis.
The investigators detail that they searched Medline/PubMed and SCOPUS databases for studies that fit the criteria of being randomised controlled trials (RCTs), compared endovascular treatments of autogenous AVF stenosis—including plain balloon angioplasty, cutting balloon angioplasty, and DCB angioplasty—and provided six-month and/or one-year patency data for each group at follow-up.
Inclusion criteria were venous outflow, anastomotic or swing area stenosis, either de novo or recurrent, and exclusion criteria were central vein stenosis or RCTs including open surgical repair or stent/stent graft arms.
Following the literature search, Tripsianis and colleagues performed a systematic review and network meta-analysis of RCTs investigating the effectiveness of plain balloon angioplasty, cutting balloon angioplasty, and DCB angioplasty in autogenous AVFs vein stenosis. They write that they included eleven RCTS in the study, reporting a total of 814 patients, of whom 395 underwent plain balloon angioplasty.
According to the authors, their network meta-analysis showed that DCB angioplasty at six months was “significantly more effective” than plain balloon angioplasty (odds ratio [OR]: 0.39, confidence intervals [CI]: 0.18–0.81) and ranked as the best treatment option, but without having statistically significant difference when compared with cutting balloon angioplasty (OR: 0.65, CI: 0.2–2.12).
Writing in JVS, the investigators also report that statistical significance was not achieved at one year among treatments, and that additional conventional pair-wise meta-analyses did not find significant differences at one year.
Tripsianis et al stress that the results of this review “should be interpreted with caution” due to some limitations. Firstly, they acknowledge that the network geometry did not provide any closed loops and write that “no direct comparison between DCB angioplasty and cutting balloon angioplasty existed, thus it was impossible to assess inconsistency between direct and indirect evidence”.
In addition, they note that there was “a considerable degree of heterogeneity” among the included RCTs and that confounding factors were present. They detail: “There was blending of various AVF configurations, de novo lesions with recurrent ones, high-pressure balloon use in a variable number, different brands of DCBs and paclitaxel dose, differences in patency reports (target lesion versus circuit patency), and difference in methodology of angioplasty regarding predilatation or post-dilatation following DCB angioplasty”.
Finally, they recognise that there was “a high risk of bias” among the included studies, especially those comparing plain balloon angioplasty with cutting balloon angioplasty. Tripsianis et al detail that most of the trials suffered from the “inherently high risk in the domain of blinding,” specifying that all but one of the included studies suffered from bias in blinding or personnel, as this is “almost impossible” in endovascular procedures. However, they note that there was some blinding of the outcome assessment in six studies.
Speaking to Vascular News, Miltos Lazarides (Democritus University, Alexandroupolis, Greece), one of the study’s senior authors, considered the present study in its wider context. He noted that a recently-published RCT had similar findings to those presented here. In the New England Journal of Medicine, Robert Lookstein (Ichan School of Medicine at Mount Sinai, New York, USA) et al found that DCB is superior to plain balloon angioplasty at six months, based on data from 330 patients.