Laser Angioplasty Using Carbon Monoxide Lasers

Abstract

ABSTRACT In this paper, we demonstrate the possibility as well as usefulness of the usage of CO lasers for the laser coronary angioplasty. CO lasers, approximately 5 ym of their wavelength, have strong ablation capacity to water-containing living tissue due to intensive attenuation by water. Accordingly, a precise ablation of intravascular obstruction without a perforation may be possible by the CO laser irradiation. As a fundamental study, the design of the fiber energy delivery of CO lasers for the coronary angioplasty and the ablation effect of the CO laser irradiation to human atheroma are revealed. The CO laser irradiation method in the flushing medium of a coronary angioscope is also discussed. 1. INTRODUCTION The removal of intravascular atheromatous plaque by a laser ablation(laser angioplasty) has been studied to solve limitations of current percutaneous transluminal angioplasty. Excluding the laser angioplasty, no method have developed to remove atheromatous plaque itself. The occlusive diseases at peripheral arteries have been successfully treated by the laser angioplasty so far.^ However, in order to apply the laser angioplasty to occlusive coronary artery diseases, many improvements are necessary to ensure essential safety of this laser therapy. The most serious problem which was reported at in vivo animal experiment is the perforation of a vascular wall by the laser irradiation due to a thermal damage to normal media.2 TO avoid this perforation, the most fundamental necessity is the selection of a laser wavelength and the laser irradiation method which can not provide temperature elevation in vessel media.In this paper, we demonstrate the possibility as well as usefulness of the CO laser coronary angioplasty. Since CO lasers, approximately 5ym of their wavelength, have strong ablation capacity to water-containing living tissue due to intensive attenuation by water, the precise ablation of intravascular obstruction may be possible without the vessel perforation.3 As a fundamental study, the design of the fiber energy delivery of CO lasers for the coronary angioplasty and the ablation effect of the CO laser irradiation to human atheroma are revealed. The CO laser irradiation method in the flushing medium of a coronary angioscope is also discussed.