HEALING CHARACTERISTICS OF INTRAARTERIAL STENT GRAFTS IN AN INJURED ARTERY MODEL

Previous investigations reveal in the absence of endothelial cell (EC) injury, intraarterial polytetrafluoroethylene (PTFE) stent graft (SG) exhibit greater EC repaving than PTFE interposition grafts (CG). The investigation evaluated EC repaving of SG compared to CG after balloon injury. Twenty adult dogs underwent SG (n = 10) or CG (n = 10) placem ent in the infrarenal aorta after balloon injury with harvest at 1 and 6 weeks. Endothelial repaving, intima-to-media height ratios (IMHR), and inflammatory stains were performed. Endothelial repaving was great er in 6-week SG compared to CG (51% +/- 5.0 versus 10% +/- 5.0, p less than or equal to 0.05). IMHR was less in 6-week SG compared to CG at the proximal (1.22 +/- 0.16 versus 1.82 +/- 0.16, p less than or equal to 0.05) and distal anastomosis (0.81 +/- 0.25 versus 1.33 +/- 0.25, p less than or equal to 0.05). Smooth muscle cell (SMC) alpha-actin wa s greater in 1-week SG compared to CG at the distal anastomosis (121.5 +/- 7.2 versus 94.0 +/- 7.2, p less than or equal to 0.05). Prolifera ting cell nuclear antigen (PCNA) was less in 6-week SG compared to CG at the proximal (5.6 +/- 1.4 versus 9.4 +/- 1.1, p less than or equal to 0.05) and distal anastomosis (3.8 +/- 0.6 versus 11.2 +/- 1.1, p le ss than or equal to 0.05). Macrophage CD-44 was less in 6-week SG comp ared to CG at the proximal (10.4 +/- 1.6 versus 32.6 +/- 3.6, p less t han or equal to 0.05) and distal anastomosis (8.6 +/- 0.9 versus 35.6 +/- 3.6, p less than or equal to 0.05). Intraarterial SG placed after balloon injury exhibited significantly greater endothelialization and less intimal hyperplasia when compared to CG.