Author/Authors :
Vitali Verin، نويسنده , , Youri Popowski، نويسنده , , Philip Urban، نويسنده , , Jacques Belenger، نويسنده , , Mireille Redard، نويسنده , , Manuel Costa، نويسنده , , Marie-Claude Widmer، نويسنده , , Michael Schwager، نويسنده , , John Kurtz، نويسنده , , Wilhelm Rutishauser، نويسنده ,
Abstract :
Intraarterial gamm irradiation reduces restenosis following balloon angioplasty. Bet irradiation has the advantages of markedly steeper dose decrease in tissue and less radioprotection problems, permitting its use in the setting of an ordinary catheterization laboratory. Flexible yttrium coils (diameter 0.016″, length 24 mm) were activated in nuclear reactor. Use of segmented balloon consisting of four interconnected compartments (*Schneider, Europe, AG) allowed for intraarterial centering of the 90Y source and homogeneous intramural dose delivery. Under fluoroscopic guidance, one carotid and one iliac artery of 21 hypercholesterolemic rabbits were deendothelialized and then simultaneously dilated and irradiated. Four dose schedules were studied: 1) control (dilated, non irradiated); 2) 6 Gray (Gy); 3) 12 Gy and 4) 18 Gy. Arterial specimens were histologically evaluated at 8 days and at 6 weeks. minimum of 5 arteries were studied in each group at each study end-point. There was significant decrease (p < 0.001-0.05) in bromodeoxyuridine incorporation and in total neointimal cell number per cm of inner arterial circumference for all radiation doses at 8 days compared to control. At 6 weeks, histological computer derived % are stenosis and mean number of neointimal cell layers were significantly reduced (p < 0.01, p < 0.005 respectively) in the group of arteries that had received 18 Gy compared to the control group, but not in the 6 or 12 Gy groups (Graph). Conclusions: (1) Intraarterial bet irradiation is feasible; (2) Radiation doses between 6 and 18 Gy effectively inhibit neointimal smooth muscle cell proliferation at 8 days; (3) This inhibitory effect is lost during the following post treatment weeks in arteries having received radiation doses of 6 or 12 Gy; (4) radiation dose of 18 Gy effectively induces long-term inhibition of neointimal hyperplasi in hypercholesterolemic rabbit model of postangioplasty restenosis.
