In developing Laser systems for ablation of atherosclerotic lesions, efforts have been made to confine the effect of the radiation to plaque and to minimize the possibility of perforation (1). Injury to adjacent tissue from thermal diffusion can be minimized if pulsed radiation is used at an exposure time shorter than the thermal relaxation time (2). The mechanism of laser ablation by pulsed radiation can be dominated by microexplosions (3). There, the ablation rate may depend on both the absorption of the laser radiation and the mechanical properties of the irradiated tissue. For tissue with similar absorption coefficients, ablation should vary with the tissue mechanical properties. To verify this hypothesis in vascular tissue, we performed several studies to determine the effect of pulsed laser radiation on the different arterial wall components that are known to have different mechanical properties but similar optical absorption. If differential ablation could be achieved. This could provide an additional safety margin for laser ablation of atherosclerotic lesions.
LaMuraglia GM, Walsh JT, Prince MR, Gregory KW: Differential ablation of arterial wall components with a pulsed CO2 laser. Surgical Forum 39:311-313, 1988.