Closure Techniques in Carotid Endarterectomy: Tracing the “Invisible” - Indirect Evidence from Randomised Controlled Trials with a Network Meta-analysis

Abstract

According to the 2017 clinical practice guidelines of the European Society for Vascular Surgery on the management of atherosclerotic carotid and vertebral artery disease, “Eversion endarterectomy is recommended over routine primary arteriotomy closure”, whereas “The choice between eversion or patched endarterectomy should be left to the discretion of the operating surgeon”.1Naylor A.R. Ricco J.B. de Borst G.J. Debus S. de Haro J. Halliday A. et al.Editor's Choice – management of atherosclerotic carotid and vertebral artery disease: 2017 clinical practice guidelines of the European Society for Vascular Surgery (ESVS).Eur J Vasc Endovasc Surg. 2018; 55: 3-81Abstract Full Text Full Text PDF PubMed Scopus (491) Google Scholar The guidelines also conclude that “There is no evidence that patch type influences outcome”.1Naylor A.R. Ricco J.B. de Borst G.J. Debus S. de Haro J. Halliday A. et al.Editor's Choice – management of atherosclerotic carotid and vertebral artery disease: 2017 clinical practice guidelines of the European Society for Vascular Surgery (ESVS).Eur J Vasc Endovasc Surg. 2018; 55: 3-81Abstract Full Text Full Text PDF PubMed Scopus (491) Google Scholar The study by Lazarides et al. represents a step forward, discriminating between the various patch types and concluding that eversion endarterectomy and patching with bovine pericardium or polytetrafluoroethylene (PTFE) are associated with a similarly low 30 day stroke and death rate, while primary closure and Dacron, vein, or polyurethane patches perform statistically significantly worse.2Lazarides M.K. Christaina E. Argyriou C. Georgakarakos E. Tripsianis G. Georgiadis G. Network meta-analysis of carotid endarterectomy closure techniques.Eur J Vasc Endovasc Surg. 2021; 61: 181-190Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar Eversion endarterectomy was also found to be associated with the lowest rate of restenosis compared with all other methods of arterial closure after carotid endarterectomy (CEA). Lazarides et al. have reached these conclusions using a novel and sophisticated methodological approach, called network meta-analysis, and should be commended for this high quality and resource demanding work. This method allows the combination of direct evidence from head to head studies, but additionally extends the analysis to incorporate indirect comparisons across trials based on a common comparator, using the effect estimates of the direct comparisons.3Salanti G. Indirect and mixed-treatment comparison, network, or multiple-treatments meta-analysis: many names, many benefits, many concerns for the next generation evidence synthesis tool.Res Synth Methods. 2012; 3: 80-97Crossref PubMed Google Scholar In this way not only does it give the full picture instead of making pairwise comparisons, but it also ranks the various treatment modalities using summary outputs. In the study by Lazarides et al., eversion endarterectomy ranked first with respect to both 30 day stroke/death and late restenosis rates, followed by PTFE and bovine pericardium patch, although readers should be aware that a high probability of being the best does not necessarily mean a large difference in clinical outcomes.2Lazarides M.K. Christaina E. Argyriou C. Georgakarakos E. Tripsianis G. Georgiadis G. Network meta-analysis of carotid endarterectomy closure techniques.Eur J Vasc Endovasc Surg. 2021; 61: 181-190Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar The evidence provided by Lazarides et al. looks robust enough, as the authors have reported evaluation of the transitivity assumption, implying that it was equally likely that any patient could have been given any of the treatments in the randomised controlled trials network. Moreover, the comparison adjusted funnel plots did not reveal any evidence of asymmetry, with no significant publication bias, thus increasing the validity of the results. However, heterogeneity in definitions among the included studies did not allow the authors to evaluate other than 30 day stroke/death and late restenosis outcomes, while the effect of other covariates could not be assessed in a meta-regression analysis. By updating and promoting the use of universal reporting standards in future studies, we might be able to further focus on modelling multiple outcomes, account for the effect of confounding factors, and draw more conclusions about the optimal closure technique during carotid endarterectomy. Editor's Choice – Network Meta-Analysis of Carotid Endarterectomy Closure TechniquesEuropean Journal of Vascular and Endovascular SurgeryVol. 61Issue 2PreviewThere is discordance between reviews comparing eversion endarterectomy (EvE) with conventional carotid endarterectomy (CEA) mostly because under this term various “closure” techniques are included, from direct closure to a wide spectrum of patches with different materials. Full-Text PDF