Division of Cardiology, Nippon Medical School, Tokyo, Japan.
J Am Coll Cardiol. 2009 Dec 29;55(1):26-32. doi: 10.1016/j.jacc.2009.08.032.
We examined the neointimal characteristics of bare-metal stents (BMS) in extended late phase by the use of optical coherence tomography (OCT).
The long-term neointimal features after BMS implantation have not yet been fully characterized.
Intracoronary OCT observation of BMS segments was performed during the early phase (<6 months, n = 20) and late phase (>or=5 years, n = 21) after implantation. Internal tissue of the BMS was categorized into normal neointima, characterized by a signal-rich band without signal attenuation, or lipid-leaden intima, with marked signal attenuation and a diffuse border. In addition, the presence of disrupted intima and thrombus was evaluated. Neovascularization was defined as small vesicular or tubular structures, and the location of the microvessels was classified into peristent or intraintima.
Normal neointima proliferated homogeneously, and lipid-laden intima was not observed in the early phase. In the late phase, lipid-laden intima, intimal disruption, and thrombus frequently were found in comparison with the early phase (67% vs. 0%, 38% vs. 0%, and 52% vs. 5%, respectively; p < 0.05). Persistent neovascularization demonstrated a similar incidence between the 2 phases. The appearance of intraintima neovascularization was more prevalent in the late phase than the early phase (62% vs. 0%, respectively; p < 0.01) and in segments with lipid-laden intima than in nonlipidic segments (79% vs. 29%, respectively; p = 0.026).
This OCT study suggests that neointima within the BMS often transforms into lipid-laden tissue during an extended period of time and that expansion of neovascularization from peristent to intraintima contributes to atherosclerotic progression of neointima.
通过光学相干断层扫描（OCT）研究裸金属支架（BMS）在延长的晚期阶段的新生内膜特征。
BMS 植入后长期的新生内膜特征尚未得到充分描述。
在植入后早期（<6 个月，n=20）和晚期（>或=5 年，n=21）对 BMS 节段进行冠状动脉 OCT 观察。BMS 的内部组织分为正常新生内膜，表现为信号丰富的无信号衰减带，或富含脂质的内膜，有明显的信号衰减和弥漫边界。此外，评估内膜破裂和血栓的存在。新生血管化被定义为小泡状或管状结构，微血管的位置分为持续性或内膜内。
正常新生内膜均匀增生，早期无脂质内膜。与早期相比，晚期更常发现脂质内膜、内膜破裂和血栓（67%比 0%，38%比 0%，52%比 5%；p<0.05）。持续性新生血管化在两个阶段的发生率相似。内膜内新生血管化在晚期比早期更常见（62%比 0%；p<0.01），在富含脂质的节段比非脂质节段更常见（79%比 29%；p=0.026）。
这项 OCT 研究表明，BMS 内的新生内膜在很长一段时间内经常转化为富含脂质的组织，并且从持续性向内膜内的新生血管化扩张有助于新生内膜的动脉粥样硬化进展。
