Duda S H, Wehrmann M, Haase K K, Huppert P E, Karsch K R, Claussen C D
Department of Diagnostic Radiology, Eberhard-Karls-University of Tübingen, Germany.
Acta Radiol. 1992 Nov;33(6):538-41.
This experimental study was designed to define the potential value of a mid-infrared holmium laser in the free running mode for angioplasty. Immediately after removal, fresh normal and diseased human cadaveric arteries were irradiated under saline with a Ho:YAG laser (wavelength 2.13 microns). The laser was pulsed at 3 Hz, 250 microseconds pulse width and fluences of 10 to 40 J/cm2. The laser beam was coupled to ring catheters with multiple low-OH quartz fibers. The tip of the delivery device was held in direct contact with the vessel surface with the laser beam oriented perpendicularly. Ablation of atherosclerotic plaque was accomplished at an ablation threshold of 10 J/cm2. The ablation rate was 2.1 to 8.3 microns/pulse. Removal of calcified plaque was only partially effective. There were marked thermal effects with vacuolizations extending up to 1505 +/- 178 microns into the adjacent tissue. Laser light at the mid-infrared wavelength of 2.13 microns is supposed to be attractive as it is readily absorbed in water and can easily be transmitted through optical fibers. However, Q-switching seems to be essential to minimize thermal side effects and to make effective ablation of calcium possible.
本实验研究旨在确定自由运行模式下的中红外钬激光在血管成形术中的潜在价值。切除后立即将新鲜的正常和病变人体尸体动脉置于盐水中，用钬钇铝石榴石激光（波长2.13微米）照射。激光以3赫兹的频率脉冲，脉冲宽度为250微秒，能量密度为10至40焦耳/平方厘米。激光束通过多根低羟基石英纤维耦合到环形导管。输送装置的尖端直接与血管表面接触，激光束垂直定向。在能量密度为10焦耳/平方厘米的消融阈值下完成动脉粥样硬化斑块的消融。消融速率为2.1至8.3微米/脉冲。钙化斑块的去除仅部分有效。存在明显的热效应，空泡化延伸至相邻组织达1505±178微米。2.13微米的中红外波长激光被认为具有吸引力，因为它很容易被水吸收并且能够很容易地通过光纤传输。然而，调Q似乎对于将热副作用降至最低以及实现钙的有效消融至关重要。
