Department of Biomedical Engineering and Cardiovascular Medicine, University of Southern California, Los Angeles, CA 90089, USA.
Biosens Bioelectron. 2013 May 15;43:237-44. doi: 10.1016/j.bios.2012.12.024. Epub 2012 Dec 20.
Identifying metabolically active atherosclerotic lesions remains an unmet clinical challenge during coronary intervention. Electrochemical impedance (EIS) increased in response to oxidized low density lipoprotein (oxLDL)-laden lesions. We hereby assessed whether integrating EIS with intravascular ultrasound (IVUS) and shear stress (ISS) provided a new strategy to assess oxLDL-laden lesions in the fat-fed New Zealand White (NZW) rabbits.
A micro-heat transfer sensor was deployed to acquire the ISS profiles at baseline and post high-fat diet (HD) in the NZW rabbits (n=8). After 9 weeks of HD, serum oxLDL levels (mg/dL) increased by 140 fold, accompanied by a 1.5-fold increase in kinematic viscosity (cP) in the HD group. Time-averaged ISS (ISSave) in the thoracic aorta also increased in the HD group (baseline: 17.61±0.24 vs. 9 weeks: 25.22±0.95dyne/cm(2), n=4), but remained unchanged in the normal diet group (baseline: 22.85±0.53dyn/cm(2) vs. 9 weeks: 22.37±0.57dyne/cm(2), n=4). High-frequency intravascular ultrasound (IVUS) revealed atherosclerotic lesions in the regions with augmented ISSave, and concentric bipolar microelectrodes demonstrated elevated EIS signals, which were correlated with prominent anti-oxLDL immuno-staining (oxLDL-free regions: 497±55Ω, n=8 vs. oxLDL-rich lesions: 679±125Ω, n=12, P<0.05). The equivalent circuit model for tissue resistance between the lesion-free and ox-LDL-rich lesions further validated the experimental EIS signals.
By applying electrochemical impedance in conjunction with shear stress and high-frequency ultrasound sensors, we provided a new strategy to identify oxLDL-laden lesions. The study demonstrated the feasibility of integrating EIS, ISS, and IVUS for a catheter-based approach to assess mechanically unstable plaque.
在冠状动脉介入治疗过程中，识别代谢活跃的动脉粥样硬化斑块仍然是一个未满足的临床挑战。电化学阻抗（EIS）对氧化型低密度脂蛋白（oxLDL）负荷的病变有反应性增加。因此，我们评估了将 EIS 与血管内超声（IVUS）和剪切力（ISS）相结合是否为评估新西兰白兔脂肪喂养模型中 oxLDL 负荷病变提供了一种新策略。
微热传递传感器用于获取新西兰白兔基线和高脂肪饮食（HD）后（n=8）的 ISS 谱。在 HD 后 9 周，血清 oxLDL 水平（mg/dL）增加了 140 倍，同时 HD 组的运动粘度（cP）增加了 1.5 倍。HD 组胸主动脉的平均 ISS（ISSave）也增加（基线：17.61±0.24 vs. 9 周：25.22±0.95dyne/cm(2)，n=4），但在正常饮食组无变化（基线：22.85±0.53dyn/cm(2) vs. 9 周：22.37±0.57dyne/cm(2)，n=4）。高频血管内超声（IVUS）显示 ISSave 增加的区域有动脉粥样硬化斑块，双极微电极显示出升高的 EIS 信号，与明显的抗 oxLDL 免疫染色相关（oxLDL 无斑块区域：497±55Ω，n=8 vs. oxLDL 丰富病变：679±125Ω，n=12，P<0.05）。病变无斑块区和 ox-LDL 丰富病变之间的组织电阻等效电路模型进一步验证了实验 EIS 信号。
通过应用电化学阻抗与剪切力和高频超声传感器相结合，我们提供了一种识别 oxLDL 负荷病变的新策略。该研究证明了将 EIS、ISS 和 IVUS 集成用于基于导管的评估机械不稳定斑块的可行性。
