Effect of balloon-expandable and self-expanding stent fixation on endoluminal polytetrafluoroethylene graft healing

Purpose To investigate the effect of stent design and deployment mechanism on endoluminal graft healing. Method Twenty dogs underwent infrarenal abdominal aorta polytetrafluoroethylene (PTFE) interposition (6) or intraluminal stented grafting using either a balloon expandable (BE, n = 8) or self-expanding (SE, n = 6) stent design. Grafts were removed at 8 weeks. Length of endothelial ingrowth and intima to media height ratios (IMHR) were calculated. Perianastomotic smooth muscle (Actin+), macrophage (CD44+), proliferating (PCNA+), and platelet-derived growth factor (PDGF+) cell content were determined. Results Mean endothelial ingrowth was 1.10 ± 0.15 cm (control), 1.88 ± 0.13 cm (BESG), and 2.16 ± 0.18 cm (SESG) proximally; and 0.94 ± 0.12, 2.11 ± 0.11 cm, and 2.16 ± 0.15 cm, respectively, at the distal anastomosis. Endothelial ingrowth was greater in all stented grafts (P< 0.001). Mean IMHRs were 1.42 ± 0.16 (control), 0.50 ± 0.14 (BESG), and 0.77 ± 0.2 (SESG) proximally; and 0.84 ± 0.1, 0.42 ± 0.09, and 0.77 ± 0.12 (SESG) distally. Lower IMHRs were observed in all stented graft regions (P< 0.05) except the distal anastomosis of SESG. The PDGF+ and PCNA+ cell content was decreased, and Actin+ cell content was increased in all stented grafts (P< 0.05). Conclusion Intraluminal location enhances endothelialization and attenuates intimal thickening in PTFE grafts. The enhanced healing of intraluminal stented grafts is irrespective of the type of stent or deployment mechanism used.