放射性支架抑制冠状动脉介入治疗后再狭窄的研究

PURPOSE Because a short half-life, high dose-rate 90Y β emitting stents more closely mimics the deliver dose rate characteristics of clinically effective β- and γ-wire and balloon brachytherapy devices, we studied the long-term effect of a new 90Y β-emitting coronary stents in canine coronary injure model and its dose-response characteristics. METHODS 90Y radioactive stents were made from electronical-deposition method. Nonradioactive stents and 90Y radioactive stents with different radiation dose(2.12, 3.30, 5.14μCi) were implanted in normal canine coronary injure model. Thirty-two animals were divided into four groups: nonradioactive controls (n=10), lower dose (n=8), moderate dose (n=7) and higher dose (n=7). Quantitative coronary angiography were performed at 3rd and 6th month. Histologic endpoints were evaluated at 6th month. RESULTS Coronary angiography found no different results between four groups at 3rd and 6th month. Histological observation atfer 6th month found that there were intima proliferation more or less in four groups. Analysis with the use of computer-assisted system showed that luminal stenosis within stent segment was significantly decreased in high-activity group compared with others (30.9±6.9% versus 37.7±7.2%, 42.9±12.1%, 38.2±8.7%,) . Pathologic　evidence of edge restenosis was seen in three radioactive stent groups. The luminal stenosis rate in adjacent, nonstented coronary segments were obviously lower copared with others (18.1±4.2% versus 27.0±7.7, 26.1±5.6, 26.9±9.4). .CONCLUSIONS 90Y β-emitting stent could not prevent the in-stent restenosis after implantation in canine coronary artery injure model and has probably an adverse effect on neointimal formation within stent segments and at the edge of stents.

冠状动脉介入治疗后再狭窄目前仍未解决。最近动物实验表明放射性支架能预防冠脉介入治疗后再狭窄。但关于放射性支架治疗再狭窄的机制尚未阐明。本实验通过小型猪冠状动脉介入治疗后再狭窄模型研究放射性支架对再狭窄的治疗作用，以及不同放射剂量的支架与治疗效果之间的关系，探讨放射性支架治疗再狭窄的机制，在动物实验基础上，推广应用于临床。