Abstract 15915: Rapamycin Eluting Biodegradable Extravascular Stent Prevents Vein Graft Stenosis at Long Term in a Canine Model
Background.Autologous veingraft stenosis and occlusion at long term have been a significant clinical issue. We tested the hypothesis that rapamycin (RM) eluting biodegradable poly L-lactic acid and epsilon-caprolactone copolymer (PLA-CL) extravascular stent can prevent graft stenosis at long term by suppressing an increase in the hemodynamic stress and also by inhibiting excessive cellular proliferation.
Methods.Femoral vein graft interposition was performed in 23 beagles. Orthotopic vein graft from the ipsilateral femoral vein was interposed on the both sides. Beagles were divided into four groups: 12 grafts interposition without a stent (control); 9 grafts with a PLA-CL stent only; and 10 grafts with a PLA-CL stent containing RM 80 μg, and 10 grafts with 800 μg. We measured stiffiness of vein graft by ultrasonography and viscoelasticity by TRY1 system, a new method utilizing a Doppler’s effect sensor. Pathohistologic analyses at anastomotic site and vein graft body were performed at 12-month interval.
Results. Stiffiness of the vein grafts increased from 23.8 to 55.8 in control, whereas it decreased from 52.2 to 23.0 in the external stent groups. Compliance of vein grafts with external stents turned into the similar value of arteries at 12-month interval. Viscoelasticity showed the paralleled results of stiffiness. Ratios of intimal area at anastomotic site tended to be lower in the two RM stent groups compared with control (0.26, 0.25, and 0.32 in 80 μg, 800 μg and control groups, respectively), furthermore, that in graft body was significantly lower in the 800 μg RM group compared with control (0.07 vs 0.15, p < 0.05).
Conclusions.Rapamycin eluting biodegradable extravascular stent can modify the long-term deterioration of vein graft compliance. In addition, the drug eluting extravascular stent can inhibit neointimal hyperplasia of vein grafts and prevent graft stenosis at long term. 293 words, 1632 characters
- © 2012 by American Heart Association, Inc.