Selective removal of cholesterol ester in atherosclerotic plaque using nanosecond pulsed laser at 5.75 µm

K. Ishii; H. Tsukimoto; H. Hazama; K. Awazu

doi:10.1117/12.764442

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20 February 2008 Selective removal of cholesterol ester in atherosclerotic plaque using nanosecond pulsed laser at 5.75 μm

K. Ishii, H. Tsukimoto, H. Hazama, K. Awazu

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Proceedings Volume 6854, Optical Interactions with Tissue and Cells XIX; 685418 (2008) https://doi.org/10.1117/12.764442
Event: SPIE BiOS, 2008, San Jose, California, United States

Abstract

Laser angioplasty, for example XeCl excimer laser angioplasty, has gained more attention in addition to conventional methods of surgical and interventional treatment of atherosclerotic diseases such as bypass operation and balloon dilatation. Low degrees of thermal damage after ablation of atherosclerotic lesions have been achieved by XeCl excimer laser at 308 nm. However, in most cases, laser ablation is not selective and normal arterial wall is also damaged. To avoid complications such as severe dissections or perforation of the arterial wall in an angioplasty, a laser light source with high ablation efficiency but low arterial wall injury is desirable. At atherosclerotic lesions, cholesterol accumulates on the tunica intima by establishing an ester bond with fatty acids such as oleic acid, and thus cholesterol ester is the main component of atherosclerotic plaques. Mid-infrared pulsed laser at 5.75 μm is selectively well absorbed in C=O stretching vibration mode of ester bonds. The purpose of this study is to determine the effectiveness of nanosecond pulsed laser at 5.75 μm irradiation of cholesterol ester in atherosclerotic plaques. In this study, we used a mid-infrared tunable solid-state laser which is operated by difference frequency generation method, with a wavelength of 5.75 μm, a pulse width of 5 nsec and a pulse duration of 10 Hz. It was confirmed that non-invasive interaction to normal thoracic aortas could be induce by the parameters, the wavelength of 5.75 μm, the average power densities of 35 W/cm² and the irradiation time under 10 sec. This study shows that nanosecond pulsed laser irradiations at 5.75 μm provide an alternative laser light source as an effectively cutting, less traumatic tool for removal of atherosclerotic plaque.

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K. Ishii, H. Tsukimoto, H. Hazama, and K. Awazu "Selective removal of cholesterol ester in atherosclerotic plaque using nanosecond pulsed laser at 5.75 μm", Proc. SPIE 6854, Optical Interactions with Tissue and Cells XIX, 685418 (20 February 2008); https://doi.org/10.1117/12.764442

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