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The Endovenous Literature: A Perfect Storm of Limited Effectiveness Data, Rapid Technological Evolution and Potential Conflict of Interest

  • David C. Bosanquet
    Affiliations
    South East Wales Vascular Network, Aneurin Bevan University Health Board, Royal Gwent Hospital, Newport, UK
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  • Christopher P. Twine
    Correspondence
    Corresponding author. South East Wales Vascular Network, Aneurin Bevan University Health Board, Royal Gwent Hospital, Cardiff Road, Newport NP20 2UB, UK.
    Affiliations
    South East Wales Vascular Network, Aneurin Bevan University Health Board, Royal Gwent Hospital, Newport, UK

    Division of Population Medicine, Cardiff University, Cardiff, UK
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Open ArchivePublished:October 20, 2017DOI:https://doi.org/10.1016/j.ejvs.2017.09.009
      The literature supporting the endovenous revolution has left clinicians and commissioning bodies in a difficult position. There are many dubiously-powered randomised studies comparing heterogeneous endpoints of limited clinical value, for a condition where the predominant aim of treatment, improvement in quality of life (QoL), has been overlooked for too long. There is a wide selection of treatment options of varying costs which are constantly being updated. Lastly, a potential conflict of interest can occur because endovenous treatment can be lucrative for both device companies and the clinician.
      How can a meta-analysis possibly hope to unpick then aggregate all of these issues? Hamann et al. have done their best to do this with the literature available,
      • Hamann S.A.S.
      • Giang J.
      • De Maeseneer M.G.R.
      • Nijsten T.E.C.
      • van den Bos R.R.
      Five-year results of great saphenous vein treatment: a meta-analysis.
      but is the literature good enough to support their conclusions? Where does this leave us when industry, clinician, and patient preference are driving superficial venous treatment forward faster than trials can keep up?
      There are some important positives to this analysis.
      • Hamann S.A.S.
      • Giang J.
      • De Maeseneer M.G.R.
      • Nijsten T.E.C.
      • van den Bos R.R.
      Five-year results of great saphenous vein treatment: a meta-analysis.
      These data have never before been collated, and the authors have avoided network meta-analysis which, while tempting, often has serious flaws. Five year follow-up increases event rates and potentially improves the power of the included trials. This is particularly important when most included trials used basic sample size calculation methodology to detect a 10% difference at 1 year and such methods use approximations that need event rates closer to 50% for validity. Regrettably, the risk of bias table highlights potential problems with incomplete outcome data,
      • Hamann S.A.S.
      • Giang J.
      • De Maeseneer M.G.R.
      • Nijsten T.E.C.
      • van den Bos R.R.
      Five-year results of great saphenous vein treatment: a meta-analysis.
      which was a missed opportunity to compensate for this potential lack of power.
      This leads to other negatives with the included trials, which are representative of the endovenous literature as a whole. The risk of bias table also shows unclear selective outcome reporting.
      • Hamann S.A.S.
      • Giang J.
      • De Maeseneer M.G.R.
      • Nijsten T.E.C.
      • van den Bos R.R.
      Five-year results of great saphenous vein treatment: a meta-analysis.
      The majority of included studies had no statement on, or had received company sponsorship, which is known to favourably bias results and conclusions.
      • Lundh A.
      • Lexchin J.
      • Mintzes B.
      • Schroll J.B.
      • Bero L.
      Industry sponsorship and research outcome.
      The primary endpoint examined is a heterogenous radiological composite: a non-patient centred, technical consideration open to manipulation by researchers. QoL was sometimes examined as a secondary outcome, but there is still the inherent problem of how to assess this for venous disease.
      Does all of this matter when clinician and patient preference is clearly driving this field faster than trials can keep up? It matters in publically funded healthcare systems. Bad trials are noticed by commissioning bodies, and funding for procedures withheld because of a ‘lack of evidence’ both in terms of clinical effectiveness, and cost.
      • Smith H.G.
      • Khan M.E.A.
      • Harrison S.L.
      • Abdul-Latiff A.
      • Hamid S.
      • Alchikhali T.
      • et al.
      Regional variations in the referral criteria for the surgical treatment of varicose veins.
      Resulting confusion over clinical benefit can mean that patients who would benefit from intervention have it withheld. So while the data available for this meta-analysis cannot support strong conclusions of effectiveness, they do highlight the important issue in the endovenous literature; we need bigger, independent trials with properly defined patient centred endpoints.

      References

        • Hamann S.A.S.
        • Giang J.
        • De Maeseneer M.G.R.
        • Nijsten T.E.C.
        • van den Bos R.R.
        Five-year results of great saphenous vein treatment: a meta-analysis.
        Eur J Vasc Endovasc Surg. 2017; 54: 760-770
        • Lundh A.
        • Lexchin J.
        • Mintzes B.
        • Schroll J.B.
        • Bero L.
        Industry sponsorship and research outcome.
        Cochrane Database Syst Rev. 2017; 2: MR000033
        • Smith H.G.
        • Khan M.E.A.
        • Harrison S.L.
        • Abdul-Latiff A.
        • Hamid S.
        • Alchikhali T.
        • et al.
        Regional variations in the referral criteria for the surgical treatment of varicose veins.
        Bull R Coll Surg Engl. 2015; 2: 70-73

      Linked Article

      • Editor's Choice – Five Year Results of Great Saphenous Vein Treatment: A Meta-analysis
        European Journal of Vascular and Endovascular SurgeryVol. 54Issue 6
        • Preview
          The most frequently used treatment options for great saphenous vein incompetence are high ligation with stripping (HL+S), endovenous thermal ablation (EVTA), mainly consisting of endovenous laser ablation (EVLA) or radiofrequency ablation, and ultrasound guided foam sclerotherapy (UGFS). The objective of this systematic review and meta-analysis was to compare the long-term efficacy of these different treatment modalities.
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