Abstract:

Objective     To identify the effect of oral administered rapamycin on the prevention of restenosis after stent implantation with intravascular ultrasound(IVUS). Methods    Forty New Zealand White rabbits underwent balloon-induced abdominal aortic wall injury and were given a diet of 1% cholesterol for 8 weeks. Then, they were divided into five groups: the control group, the oral rapamycin group(RAPA group), the bare metal stent group(BMS group), the bare metal stent with oral rapamycin group(BMS+RAPA group) and the rapamycin eluting stent group(DES group). Rabbits in the RAPA and BMS+RAPA groups received a daily oral dose of rapamycin(0.5mg/kg), whereas rabbits in other groups received no medications. All the rabbits were euthanized after the 4-week intervention. Serum lipids were measured and intravascular ultrasound(IVUS) was performed. The minimal luminal diameter(MLD), external elastic membrane(EEM) area, lumen area(LA), and plaque area(PA), plaque burden(PB) were measured, and thelumen eccentricity index, remodeling index and lumen reduction were calculated.  Results     After the 4-week intervention, there was no significant difference of serum lipid levels among the five groups. Oral administration of rapamycin in the RAPA and BMS+RAPA groups showed similar effects in  reducing PA and PB as the DES group, which all were better than the control and BMS group. The BMS+RAPA group and DES group showed much more MLD and less lumen reduction, compared with the BMS group(P<0.05). Conclusions     Oral administration of rapamycin demonstrates the same effect in the reduction of plaque burden and stent restenosis as the rapamycin eluting stent.

Key words: Intravascular ultrasound; Arteriosclerosis; Stents; Rapamycin; Restenosis; Rabbit