Excimer lasers in cardiovascular surgery: Ablation products and photoacoustic spectrum of the arterial wall

Abstract

Photoacoustic spectra of normal artery wall and of atherosclerotic plaque are reported. Threshold fluences for ablative formation of gaseous products for each excimer laser line were calculated from the photoacoustic spectrum and the measured threshold for the KrF laser.

Spectroscopic characterization of cardiovascular tissue

“…The interaction of pulsed ultraviolet radiation with biological tissue is characterized by precise nonthermal cutting of the tissue [Srinivasan, 1986;Singleton et al, 1986;Deckelbaum et al, 19851. This nonthermal cutting process has been termed "ablative photodecomposition" or "photoablation" and has been proposed as a method for the recanalization of arteries clogged with atherosclerotic plaque [ Srinivasan, 19861. While some have attempted to model this process, the actual mechanism is still a matter of controversy [Srinivasan, 1986;Keyes et al, 19851. If the pulsed excimer laser radiation is of sufficiently high fluence, then radiation impinging on the surface will result in plasma formation accompanying photoablation.…”

Formation of pressure waves during in vitro excimer laser irradiation in whole blood and the effect of dilution with contrast media and saline

“…However, the concept of tissue ablation without injury to adjacent vessel wall structures 2141 seems to be limited because intimal dissections and perforations were documented following laser angioplasty [ 13,15,161. The observation of a rapidly expanding and then collapsing vapour bubble [61 and the occurrence of pressure waves [1,4,17,181, both of which are associated with the ablation of vascular tissue, may explain the trauma to vessel wall structures next to the irradiated area [4,6,191. Excimer laser light with a wavelength of 308 nm is absorbed in blood.…”

<title>Current and future use of lasers in vascular neurosurgery</title>

“…Shortly after his invention, several physicians began exploring the potential use of different types of Laser in medicine. The pioneering effort of Rosomoff and Lambert were directed toward describing the ablative effects of Laser radiation on brain tissue (43,62).…”