Development of an intravascular laser treatment with an infrared free electron laser. Selective removal of cholesterol ester in carotid atheromatous plaques.

SUMMARY: We have studied to develop an intravascular device with an infrared free electron laser (FEL) to treat occlusive carotid atherosclerotic lesions. In this study, we irradiated the FEL with a wavelength of 5.75 mum on surgical specimens of human atheromatous carotid plaques. After the irradiation on a cholesterol-ester-accumulated portion of the carotid plaques under proper conditions, a microscope transmission FTIR (Fourier Transform Infrared) spectroscopy showed that the peak of a tissue infrared absorption spectrum corresponding to the molecular vibration of cholesterol ester (5.75 mum) disappeared.Tissue damages associated with the irradiation were not histologically noted. This study demonstrated that irradiation of FEL can selectively remove cholesterol ester from the human atheromatous carotid plaques.