Biodegradable Magnesium Alloy Stents as a Treatment for Vein Graft Restenosis

ABSTRACT

PURPOSE: To explore the effects of biodegradable magnesium alloy stents (BMAS) on remodeling of vein graft (VG) anastomotic restenosis. MATERIALS AND METHODS: To establish a VG restenosis model, seventy two New Zealand rabbits were randomly divided into three groups according to whether a stent was implanted in the graft vein or not. BMASs and 316L stainless steel stents were implanted in BMAS and 316L groups, respectively, while no stent was implanted in the no-treatment control group (NC group). Loss of lumen diameter in the graft vein was measured in all three groups. Upon harvesting VG segments to evaluate intimal proliferation and re-endothelization, the degradation and biological safety of the stents were observed to explore the effects of BMAS on VG remodeling. RESULTS: Model establishment and stent implantation were successful. The BMAS reduced lumen loss, compared with the control group (0.05±0.34 mm vs. 0.90±0.39 mm, p=0.001), in the early stage. The neointimal area was smaller in the BMAS group than the 316L group after 4 months (4.96±0.66 mm2 vs. 6.80±0.69 mm2, p=0.017). Re-endothelialization in the BMAS group was better than that in the 316L group (p=0.001). Within 4 months, the BMAS had degraded, and the magnesium was converted to phosphorus and calcium. The support force of the BMAS began to reduce at 2–3 months after implantation, without significant toxic effects. CONCLUSION: BMAS promotes positive remodeling of VG anastomosis and has advantages over the conventional 316L stents in the treatment of venous diseases.