Argon ion laser atheroablation: influence of plaque composition

This study quantifies the relationship between exposure time, depth of penetration, extent of lateral and deep cellular disruption (LCD and DCD, respectively), and the intrinsic resistance of different grades of atherosclerotic plaque. Argon ion laser atheroablation (AILA) was accomplished via a 200-micro quartz fiber using 2.0 and 5.0 watts of power for standard exposure times in fibrofatty, calcified, and complicated cadaveric human aortic plaque. Gross and histologic analyses revealed the following information: 1. The extent of LCD and DCD increased minimally with longer exposure times, irrespective of plaque grade or laser wattage. 2. At both levels of power, the average rate penetration was slower in calcified than in fibrofatty plaque (p<0.01). 3. Increasingly the laser power increased the rate of penetration per unit of energy. 4. The rate of penetration was quite variable, even among plaques of the same grade, depending on the calcium composition of each sample. In summary, AILA was found to be significantly affected by plaque composition, whereas energy efficiency and accuracy could be maximized by increasing the laser wattage.