|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1994 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1993 : ¥1,300,000 (Direct Cost : ¥1,300,000)
The usefulness of percutaneous transluminal angioplasty (PTA) for treatment of the atherosclectic occlusive lesions has been widely accepted. In spite of its high initial success rate, the restenosis remains a major problem. Restenosis after successful PTA are mainly caused by intimal hyperplasia. Proliferative smooth muscle cells play an important role in the process of intimal hyperplasia. Since proliferative cells are generally radiosensitive, radiation therapy may be useful in this issue.
This experimental study was designed to investigate the effect of irradiation for prevention of intimal hyperplasia. Twenty atherosclerotic rabbits, fed with cholesterol-containing diet, were divided into four groups which were irradiated 2,5,10, and 20 Gy, respectively. The intima of both femoral arteries was performed on the unilateral side. The contralateral femoral artery served as a control. Angiograms as well as histologic specimens were obtained one month later.
There were no significant differences in thickness of intimal hyperplasia beween irradiated and control sites in groups irradiated with 2 and 5 Gy. However, in a 10 Gy-irradiated group, intimal hyperplasia of the irradiated site was significantly suppressed. Medial thinning without intimal hyperplasia, which probably caused dilatation of the lumen on angiography, was observed in a 20 Gy-irradiated group. Radiation therapy may prevent intimal hyperplasia. Further investigation on the optimal dose and timing of irradiation may be needed.