Schaar Johannes A, de Korte Chris L, Mastik Frits, Baldewsing Radj, Regar Evelyn, de Feyter Pim, Slager Cornelis J, van der Steen Anton F W, Serruys Patrick W
Thorax Center, Erasmus Medical Center, Rotterdam, The Netherlands.
Herz. 2003 Sep;28(6):488-95. doi: 10.1007/s00059-003-2488-6.
The composition of an atherosclerotic plaque is considered more important than the degree of stenosis. An unstable lesion may rupture and cause an acute thrombotic reaction. Most of these lesions contain a large lipid pool covered by an inflamed thin fibrous cap. The stress in the cap increases with decreasing cap thickness and increasing macrophage infiltration. Intravascular ultrasound (IVUS) palpography might be an ideal technique to assess the mechanical properties of high-risk plaques.
Palpography assesses the local mechanical properties of tissue using its deformation caused by the intraluminal pressure. IN VITRO VALIDATION: The technique was validated in vitro using diseased human coronary and femoral arteries. Especially between fibrous and fatty tissue, a highly significant difference in strain (p = 0.0012) was found. Additionally, the predictive value to identify the vulnerable plaque was investigated. A high-strain region at the lumen-vessel wall boundary has an 88% sensitivity and 89% specificity for identifying such plaques. IN VIVO VALIDATION: In vivo, the technique was validated in an atherosclerotic Yucatan minipig animal model. This study also revealed higher strain values in fatty than fibrous plaques (p < 0.001). The presence of a high-strain region at the lumenplaque interface has a high predictive value to identify macrophages. PATIENT STUDIES: Patient studies revealed high-strain values (1-2%) in thin-cap fibrous atheroma. Calcified material showed low strain values (0-0.2%). With the development of three-dimensional (3-D) palpography, identification of highstrain spots over the full length of a coronary artery becomes available.
Intravascular palpography is a unique tool to assess lesion composition and vulnerability. The development of 3-D palpography provides a technique that may develop into a clinical tool to identify the high-risk plaque.
动脉粥样硬化斑块的成分被认为比狭窄程度更为重要。不稳定病变可能破裂并引发急性血栓反应。这些病变大多含有一个被炎症薄纤维帽覆盖的大脂质池。随着帽厚度减小和巨噬细胞浸润增加，帽中的应力会增大。血管内超声（IVUS）触诊术可能是评估高危斑块力学特性的理想技术。
触诊术利用腔内压力引起的组织变形来评估组织的局部力学特性。
该技术在体外使用病变的人体冠状动脉和股动脉进行了验证。特别是在纤维组织和脂肪组织之间，发现应变存在高度显著差异（p = 0.0012）。此外，还研究了识别易损斑块的预测价值。管腔 - 血管壁边界处的高应变区域识别此类斑块的灵敏度为88%，特异性为89%。
在体内，该技术在动脉粥样硬化的尤卡坦小型猪动物模型中进行了验证。这项研究还显示，脂肪斑块中的应变值高于纤维斑块（p < 0.001）。管腔 - 斑块界面处高应变区域的存在对识别巨噬细胞具有较高的预测价值。
患者研究显示，薄帽纤维粥样斑块中的应变值较高（1 - 2%）。钙化物质的应变值较低（0 - 0.2%）。随着三维（3 - D）触诊术的发展，可以在冠状动脉全长上识别高应变点。
血管内触诊术是评估病变成分和易损性的独特工具。三维触诊术的发展提供了一种可能发展成为识别高危斑块的临床工具的技术。
