Laser angioplasty: history, current state, problems and prospects

Abstract

Laser angioplasty has been used in clinical practice since the 1980s. The technique has evolved from the use of continuous laser radiation with unfavorable results in the form of occlusion of more than 2/3 of treated arteries in the early postoperative period due to severe thermal damage of surrounding tissues to the implementation and use of pulsed lasers with a significantly lower thermal effect. Currently, in the world practice, the excimer laser is used for laser angioplasty in the vast majority cases. The article analyzes the parameters of this laser, identifies problems and discusses possible solutions. It is determined that the excimer laser cannot be considered effective in the long term: the wavelength, the energy that is well absorbed by hemoglobin and iodine-containing contrast, impossibility to transmit high energy density of laser radiation from the laser source into the artery through an optical fiber, high frequency of pulse generation, that increases thermal damage of intact tissues of the arterial wall and following risk of vessel restenosis. At a laser radiation wavelength of 600—1000 nm, the vast majority of tissues are optically transparent and there is little absorption by both atherosclerotic plaque and surrounding tissues. The search for selection of an additional chromophore having absorption spectrum in this range, which would be selectively accumulated only by atherosclerotic tissues and not by intact vascular wall, seems promising. The effect of pulsed laser radiation with a wavelength of 600—1000 nm and a low frequency of pulse generation would selectively destroy atherosclerotic plaque without damaging the surrounding structures.