Commentary on “Tacrolimus Eluting Suture Inhibits Neointimal Hyperplasia: An Experimental In Vivo Study in Rats”

Abstract

In their paper Ak et al. deal with one of the main issues in vascular surgery, anastomotic neointimal hyperplasia.1Ak K. Ak E. Dericioglu O. Canak T. Akbguba J. Ozkan N. et al.Tacrolimus eluting sutures inhibits neointimal hyperplasia: an experimental in vivo study in rats.Eur J Vasc Endovasc Surg. 2017; 53: 438PubMed Google Scholar The paper offers some interesting points of research that could lead to clinical applications; however, some parts of the paper require discussion. The technology and the drug elution distribution: the authors evaluated in vitro tacrolimus elution but there is no proof that in vivo, after suture completion, the same elution occurs with the same quantity of tacrolimus on the overall length of the running suture. For example, it cannot be excluded that pulling the suture thread through the arterial or synthetic prosthetic wall would not partially wash out the tacrolimus on the surface of the suture or modify further elution of the drug. This point, related to the strength of the link of the coating to the biomaterial, should be assessed. Different strategies have been proposed to control arterial remodelling after trauma, such as the suturing of the anastomosis including luminal2Thierry B. Winnik F.M. Merhi Y. Tabrizian M. Nanocoatings onto arteries via layer-by-layer deposition: toward the in vivo repair of damaged blood vessels.J Am Chem Soc. 2003; 125: 7494-7495Crossref PubMed Scopus (181) Google Scholar and adventitial3Mátyás L. Berry M. Menyhei G. Tamás L. Acsády G. Cuypers P. et al.The safety and efficacy of a paclitaxel-eluting wrap for preventing peripheral bypass graft stenosis: a 2-year controlled randomized prospective clinical study.Eur J Vasc Endovasc Surg. 2008; 35: 715-722Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar approaches. The present approach allows delivery of the drug to the three arterial layers but not homogeneously on the suture line. These differences could mainly be observed on larger anastomoses where the specific surface of the threads and consequently the amount of drug delivered is lower. Further studies with longer than 1 month duration of implantation should be considered to exclude the potential adverse effects of drugs.4Kolodgie F.D. Pacheco E. Yahagi K. Mori H. Ladich E. Virmani R. Comparison of particulate embolization after femoral artery treatment with IN.PACT Admiral versus Lutonix 035 paclitaxel-coated balloons in healthy swine.J Vasc Interv Radiol. 2016; 27: 1676-1685Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar, 5Kollum M. Farb A. Schreiber R. Terfera K. Arab A. Geist A. et al.Particle debris from a nanoporous stent coating obscures potential antiproliferative effects of tacrolimus-eluting stents in a porcine model of restenosis.Catheter Cardiovasc Interv. 2005; 64: 85-90Crossref PubMed Scopus (75) Google Scholar These adverse effects could be potentiated by tissue anoxia or necrosis related to the stitches. The relevance of the model: the authors chose a model of longitudinal suture on rat abdominal aorta using a 7/0 polypropylene running suture. Even though the authors appropriately discussed their choice, performing such a longitudinal anastomosis is at risk of stenosis and consequently of calibre variability leading to haemodynamic differences that could influence healing, as intra-operative angiographic evaluation of the quality of the surgical procedure was not performed. Further studies including models of bypasses with an end to side anastomosis to an artery or for performing an arterio-venous fistula are suggested, as they are most often responsible for neointimal hyperplasia in clinical practice. As a conclusion, this interesting work suggests opportunities for improving the performance of anastomoses at high risk of neointimal hyperplasia. However, the concept must be more extensively evaluated by experimental studies as recommended, and next on clinical studies evaluating the optimal indications and cost effectiveness of the technology. Tacrolimus-Eluting Suture Inhibits Neointimal Hyperplasia: An Experimental In Vivo Study in RatsEuropean Journal of Vascular and Endovascular SurgeryVol. 53Issue 3PreviewNeointimal hyperplasia (NIH) remains one of the leading causes of graft failure after vascular anastomoses. Cytotoxic drugs, such as rapamycin and tacrolimus, have been shown to inhibit the development of NIH. In this study, the aim was to test the impact of a sustained releasing tacrolimus–chitosan-eluting suture on the development of NIH in a rat model. Full-Text PDF Open Archive