Experimental coronary angioplasty using a UV-Excimer laser.

Both conventional Argon- and NdYAG-lasers in continuous wave or pulsed application and far ultraviolet laser radiation are able to cause a loss of substance of biologic tissue. The thermic and ablative effects of NdYAG-lasers and UV-Excimer lasers at the wavelengths of 193 nm (ArF) and 248 mm (KrF) on inconspicuous and atherosclerotic human and animal coronary vessels were compared by histologic and, in some cases, by scanning electron microscopic examinations. Whereas common lasers generally produce thermal injuries of the surroundings, pulsed far ultra-violet radiation is characterized by a lack of thermic damage. The UV-radiation in vitro cleaned precise defects of substance, and assessable tissue-removing effects were found. These results were influenced by the wavelength used. In general, the removing effect was good in normal and atherosclerotic tissue, whereas massive calcification was very resistant. Excimer lasers seem to be preferable for ablation of atherosclerotic tissue, but still there is a great number of technical problems to be solved until use in the clinical setting can be justified.