A Bioabsorbable, Paclitaxel-Eluting Mesh Inhibits Intimal Hyperplasia in a Sheep Model of Dialysis Access Failure

Ted R. Kohler, MD, Philip M. Toleikis, PhD, David M. Gravett, PhD and Rui Avelar, MD
University of Washington, Vascular Surgery, Seattle VA PSHCS, Seattle, WA and Vancouver, BC, Canada

Objective: To evaluate the effect of a bioabsorbable, paclitaxel-eluting mesh on anastomotic intimal hyperplasia in polytetrafluoroethylene (PTFE) arteriovenous grafts in sheep.
Methods: Commercially available PTFE grafts (6 mm ID) were placed between the left common carotid artery and right external jugular vein in 40 neutered male sheep. Animals (8 per group) were randomized to one of five groups: no mesh; or, absorbable mesh with 0.0, 0.6, 1.3 or 2.2 mg paclitaxel. In the latter four groups, a 3 X 6 cm mesh containing paclitaxel (Vascular Wrap™, Angiotech, Vancouver, Canada) was applied to the distal end of the graft and venous anastomosis. Doppler examinations were performed weekly to evaluate graft patency. At eight weeks, animals were euthanized and grafts were perfusion-fixed and harvested. Six cross sections were cut at the venous end of the graft and vessel for computer-assisted morphometery by a blinded observer.
Results: Grafts occluded early in five animals (12.5%) prior to the scheduled harvesting date; these animals were excluded from the study and not replaced. Grafts in the remaining 35 animals were patent at the time that the animals were euthanized. The venous suture lines were intact and the adjacent vein had normal morphology in all animals. Key morphometric outcomes are presented in the table below for the cross-section taken perpendicular to the graft at its most distal end.
Conclusions: In this sheep model, the paclitaxel-eluting mesh significantly inhibits neointimal hyperplasia at the venous anastomosis and capillary ingrowth into the neointima without injury to the adjacent vein.