Waksman R
Cardiology Research Foundation, Washington Hospital Center, Washington, DC 20010, USA.
Semin Interv Cardiol. 1997 Jun;2(2):95-101.
Intracoronary radiation therapy for prevention of restenosis is a new emerging technology which is tested nowadays in clinical trials. Several methods of radiation and a variety of isotopes have been tested in different animal models in order to prove the concept and to find a friendly user system for this application. Using the same treatment doses both gamma and beta emitters demonstrated similar results despite differences in isotope characteristics: penetration, activity, dose rate and treatment time. In addition, intracoronary radiation delivered via a catheter-based system prior to coronary stenting showed reduction of neointimal hyperplasia in the porcine coronary stent model and may further reduce restenosis coupled to stent implantation. The value of radioactive stents is also considered especially in large vessels with regard to their low activity and their proximity to the vessel wall. Adventitial labeling and immunostaining suggested the mechanism by which radiation reduces smooth muscle cell proliferation at the adventitia and affects on favorable vessel remodeling. These studies which were pioneered in this new field and have facilitated the clinical trials of using radiotherapy for prevention of restenosis are reviewed and discussed in this paper.
冠状动脉内放射治疗预防再狭窄是一项新兴技术，目前正在临床试验中进行测试。为了证明这一概念并找到适用于该应用的用户友好系统，已经在不同动物模型中测试了几种放射方法和多种同位素。尽管同位素特性（穿透性、活性、剂量率和治疗时间）存在差异，但使用相同的治疗剂量时，γ和β发射体显示出相似的结果。此外，在冠状动脉支架置入术前通过基于导管的系统进行冠状动脉内放射，在猪冠状动脉支架模型中显示出新内膜增生减少，并且可能进一步降低与支架植入相关的再狭窄。放射性支架的价值也受到关注，特别是对于大血管，因为其活性低且靠近血管壁。外膜标记和免疫染色提示了放射减少外膜平滑肌细胞增殖并影响有利的血管重塑的机制。本文对这个新领域中开创性的这些研究进行了综述和讨论，这些研究推动了使用放射疗法预防再狭窄的临床试验。
