Abstract

Paclitaxel is a microtubule stabilising drug, with the potential to suppress smooth muscle cell proliferation, migration and also to interfere with signal transduction. The aim of the study was to evaluate the safety and efficacy of locally-delivered paclitaxel on neointima formation after coronary stent implantation in the pig model. Thirty domestic pigs underwent stent implantation of the left anterior descending artery. In the treatment group(n=10), 5 ml paclitaxel (10 μmol/l) was delivered with an Infusasleeve II catheter following stenting. The animalswere sacrificed 4 weeks later. Vessels were perfusion-fixed and morphometric analysis was performed using conventional techniques. Furthermore, the extent of injury was determined at each stentstrut area. Correlation of local injury and neointimal thickness was evaluated by linear regression. Re-endothelialisation was assessed followingstaining with von Willebrand Factor. There were no statistical differences of neointimal thickness (Paclitaxel [P] 0.9± 0.3 vs Control [C] 0.8± 0.3mm),neointimal area (P 3.0± 0.9 vs C 2.2± 1.0mm2) and the lumen area (P 3.1± 1.7 vs C 2.8± 0.8mm2) between the twogroups. However, medial area (2.4± 0.2 vs 1.5± 0.4mm2) was greater in the vessels treated with paclitaxel (p < 0.05).Paclitaxel had no significant effect on endothelial regrowth compared to controls. These preliminary data show that local delivery of paclitaxel with the Infusasleeve catheter did not reduce neoin-tima formation following stent implantation in native pig coronary arteries.

Keywords: Angioplasty, pig, restenosis, paclitaxel, local drug delivery