Factors influencing ablation of atherosclerotic plaque with argon laser.

The ablative effect of argon laser delivered fibreoptically in vitro on 234 segments of atherosclerotic human aorta was studied. The variables such as energy density, type of atheroma and immersion media were included, and all irradiated specimens were subsequently submitted to histological examination and crater volumes in mm3 to micrometer measurements under light microscope. The results showed 1) a linear relationship between energy dose and crater volume in fibrous atheroma, 2) significantly greater damage or surrounding in the higher energy dose groups, 3) a lower dose response in calcified tissue than in fatty streaks or fibrous atheroma, and 4) immersion of tissue in blood during ablation resulted in a significantly greater dose response than immersion in plasma or saline, and the corresponding surrounding tissue damage was greatest when immersed in blood. Thus, argon laser is both effective and predictable in response during ablating of atheromatous tissue. The efficacy of the process is dependent on immersion medium, while the degree of surrounding tissue damage is dependent on energy dose.