STENTS WRAPPED IN AUTOLOGOUS VEIN - AN EXPERIMENTAL-STUDY

Objectives. A new type of coated stent, consisting of a conventional s tent covered by an autologous vein graft, was developed at our institu tion. Background. Coated stents are under investigation to address ste nting limitations. However, experimental implantation of coated stents covered by autologous tissue has not been reported. Methods. An autol ogous vein graft was removed and carefully prepared. Subsequently, a P almaz stent was covered by the vein graft both internally and external ly. Twenty-seven stents were implanted in the normal iliac arteries of 27 pigs weighing 18 to 33 kg. in 15 of the pigs, 15 noncoated Palmaz stents were implanted in the contralateral artery; these animals serve d as the control group. The animals were followed up angiographically for a period ranging from 7 days to 6 months. At the time of death, th e stented segments mere removed, and histomorphometric analysis was pe rformed. Results. Autologous vein graft-coated stent preparation and i mplantation was feasible and uncomplicated. In both stents, angiograph ic follow-up revealed the absence of thrombosis, except for two cases of subacute thrombosis in the control group. The thickness of the inti mal layer was greater in the coated stents and seems to be due to the existence of the internal vein layer ([mean +/- SD] 0.57 +/- 0.12 vs. 0.27 +/- 0.13 mm, p = 0.001). The arterial media of the coated stent s egments was thinner than that in the control group (0.14 +/- 0.03 vs. 0.18 +/- 0.01 mm, p = 0.02). Conclusions. The autologous vein graft-co ated stent seems to be nonthrombogenic, and only minimal hyperplasia w as observed in the pigs. Further studies are needed to explore the eff icacy of this technique in humans.