Kim H S, Chan R C, Kollum M, Au A, Tio F O, Yazdi H A, Ajani A E, Waksman R
Cardiovascular Research Institute, Washington Hospital Center, Washington, DC 20010, USA.
Int J Radiat Oncol Biol Phys. 2001 Nov 15;51(4):1058-63. doi: 10.1016/s0360-3016(01)02601-3.
The major limitation of coronary stenting remains in-stent restenosis, due to the development of neointimal proliferation. Radioactive stents have demonstrated the ability to reduce this proliferation in the healthy nonatherosclerotic porcine animal model. However, inhibition of tissue proliferation in the in-stent restenotic lesion in a porcine model is not well characterized. The objective of this study was to examine the efficacy and safety of the 32P radioactive stent for the treatment of in-stent restenosis in a double stent injury model of the porcine coronaries.
Eighteen coronary arteries in 9 pigs underwent nonradioactive stent (8 mm in length) implantation. Thirty days after the initial stent implantation, a 32P radioactive stent (18 mm in length) with an activity of 0 and 18 microCi was implanted to cover the initial stent. The swine were killed 30 days after the second stent implantation. Histomorphometric analysis was performed for vessel area (VA), stent strut area (SSA), intimal area (IA), and lumen area (LA).
Injury scores, VA, SSA, and LA were similar among the control and radiated groups. Neointimal formation was significantly reduced after placement of radioactive stents as compared to control in both the overlapped (0.93 +/- 0.12 vs. 1.31 +/- 0.51 mm(2), p < 0.05) and nonoverlapped segments (1.14 +/- 0.21 vs. 1.91 +/- 1.04 mm(2), p < 0.05). The smooth muscle cell index in the neointima was reduced. Intimal fibrin was increased in the radiated group as compared to the control (p < 0.01 respectively).
32P radioactive stents may be safe and effective in reducing neointimal formation leading to in-stent restenosis. Longer follow-up will be required to examine whether these positive findings can be maintained.
由于新生内膜增殖的发展，冠状动脉支架置入术的主要局限性仍然是支架内再狭窄。放射性支架已在健康的非动脉粥样硬化猪动物模型中显示出减少这种增殖的能力。然而，在猪模型中，对支架内再狭窄病变中组织增殖的抑制作用尚未得到充分表征。本研究的目的是在猪冠状动脉双支架损伤模型中检验32P放射性支架治疗支架内再狭窄的疗效和安全性。
9头猪的18条冠状动脉接受了非放射性支架（长度8mm）植入。在初次支架植入后30天，植入一个活性为0和18微居里的32P放射性支架（长度18mm）以覆盖初次植入的支架。在第二次支架植入后30天处死猪。对血管面积（VA）、支架小梁面积（SSA）、内膜面积（IA）和管腔面积（LA）进行组织形态计量分析。
对照组和放射组之间的损伤评分、VA、SSA和LA相似。与对照组相比，放射性支架置入后，重叠段（0.93±0.12 vs. 1.31±0.51mm²，p<0.05）和非重叠段（1.14±0.21 vs. 1.91±1.04mm²，p<0.05）的新生内膜形成均显著减少。内膜中平滑肌细胞指数降低。与对照组相比，放射组内膜纤维蛋白增加（分别为p<0.01）。
32P放射性支架在减少导致支架内再狭窄的新生内膜形成方面可能是安全有效的。需要更长时间的随访来检验这些阳性结果是否能够维持。
