Vincent G M, Fox J, Johnson M D, Strickland R, Garry S L, Hammond E
Department of Medicine, LDS Hospital, Salt Lake City, UT 84143.
Lasers Surg Med. 1990;10(5):420-6. doi: 10.1002/lsm.1900100504.
Thermal laser angioplasty uses constant laser power, producing widely variable tip temperatures in vivo. Results have been suboptimal. We studied the effect of 50-400 degrees C tip temperatures on depth of ablation at 192 sites on plaqued and normal human aorta in vitro, and the angiographic and histologic response in vivo of 300-400 degrees C at probe/vessel ratios of 0.5-1.0, in 40 normal canine femoral artery segments. In vitro, there was a direct relationship between tip temperature and depth of ablation, r = 0.71 (all segments), r = 0.74 for fibrous plaque, but a poor correlation in fatty plaque r = 0.35. In fibrous plaque, there was proportionately more ablation at tip temperatures greater than 300 degrees C, mean depth 0.62 mm, than at 150-300 degrees C, mean 0.37 mm, (P less than .001). Ablation was similar in plaqued and normal aorta. In vivo, 300 degrees C, 350 degrees C, and 400 degrees C produced similar effects. At probe/vessel ratios less than 0.8, only disruption of internal elastic lamina was observed. At ratios greater than or equal to 0.8, spasm occurred in 39% (7/18), transmural damage in 28% (5/18), and perforation in one of 18. Ablation is not selective for plaque and is highly variable in fatty plaque. Tip temperatures above 300 degrees C produce greater ablation than at lower temperatures. In clinical applications, probe/vessel rations less than or equal to 0.7 may be most appropriate, and it appears that thermal remodeling may contribute more to outcome than plaque ablation.
热激光血管成形术使用恒定的激光功率，在体内会产生广泛变化的尖端温度。结果并不理想。我们在体外研究了50 - 400摄氏度的尖端温度对有斑块和正常人体主动脉192个部位消融深度的影响，以及在40条正常犬股动脉段中，以0.5 - 1.0的探头/血管比例，300 - 400摄氏度在体内的血管造影和组织学反应。在体外，尖端温度与消融深度之间存在直接关系，r = 0.71（所有段），纤维斑块的r = 0.74，但在脂肪斑块中相关性较差，r = 0.35。在纤维斑块中，尖端温度高于300摄氏度时，平均深度为0.62毫米，比150 - 300摄氏度时（平均0.37毫米）有更多成比例的消融（P小于0.001）。有斑块和正常主动脉中的消融情况相似。在体内，300摄氏度、350摄氏度和400摄氏度产生相似的效果。当探头/血管比例小于0.8时，仅观察到内弹力层破坏。当比例大于或等于0.8时，39%（7/18）发生痉挛，28%（5/18）出现透壁损伤，18条中有1条发生穿孔。消融对斑块没有选择性，在脂肪斑块中变化很大。高于300摄氏度的尖端温度比低温时产生更大的消融。在临床应用中，探头/血管比例小于或等于0.7可能最合适，而且似乎热重塑对结果的贡献可能比斑块消融更大。
