准分子激光对不同成分粥样斑块的消蚀效应

Excimer Laser Ablation of Different Types of Human Atherosclerotic Aorta Plaques

本文应用308nm XeCI准分子激光照射粥样硬化的人尸主动脉及钙化的二尖瓣叶,观察准分子激光对正常主动脉、不同程度的脂肪斑块、纤维斑块及钙化的二尖瓣叶所产生的组织效应。结论:准分子激光可用于消蚀粥样硬化斑块,但对不同成分的斑块消蚀效应不同,其中对以脂质成分为主的斑块消蚀最明显,其次为纤维斑块。对严重钙化的组织不能产生理想的消蚀效应。

47 atherosclerotic aorta segments, 18 normal aorta segments and 12 heavily calcified mitral valves were seperately irradiated with XeCl 308 nm excimer laser Laser parameters used in this study were: pulse energy 40mJ, frequency 10Hz, radiation duration 10s. In the group of calcified valves, pulse energy was 40 or 70mJ and radiation duration was 20 or 30s. The tissue sections were stained with hematoxylin-eosin and examined by light microscopy. The depth, width and largest section area of the craters were measured using a computer-assisted image analysis system The aorta segments were identified by light microscopy and divided into 4 groups: (1) normal aorta group(N), n=18, (2) mild atherosclerotic plaque group (L), n=20, (3) heavily atherosclerotic plaque group(H), n=15, (4)fibrous plaque group (F), n=12 and (5) calcified valve group (C), n=12 In all aorta segments irradiated by excimer laser except group C, clear craters were formed without a surrounding thermal damage zone and characterized by coagulative necro sls.The shape and size of crater section were very different In N and L group, craters shewed a 'V' shape; in H group they were wider and larger; in F group they resembled a dish and the craters in C group were irregular The depth of craters in H group were deeper than F group (P<0.05). The top diameter of craters and section area in H group were much larger than those in F, L, N groups(P<0.01) Such results perhaps are related to that fatty tissue is different from normal tissue in absorbing photoelectric energy.Another cause may be that the binding energy of the two kinds of molecules is different. It was very difficult to ablate heavily calcified tissue with excimer laser.