Effects of varying argon ion laser intensity and exposure time on the ablation of atherosclerotic plaque

✍ Scribed by Sipke Strikwerda; Corinne Bott-Silverman; Norman B. Ratliff; Marlene Goormastic; Robert M. Cothren; Ben Costello; Carter Kittrell; Michael S. Feld; John R. Kramer

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 620 KB
• Volume: 8
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/lsm.1900080112

✦ Synopsis

Using continuous wave (CW) argon ion laser light, a total of 253 laser exposures of varying power (1.5, 3,5,8 or 10 w) and duration (20-1333 ms) were delivered to four segments of human atheromatous aorta obtained at autopsy. Exposure conditions were controlled by using an optically shielded laser catheter that provided a 500 pm spot of light of known power. Two thresholds for consistently reproducible ablation could be defined-an intensity threshold at 25.5 W/mm2 and a fluence threshold at 3.2 J/mm2. Above threshold, a fluence of 5.1 J/mm2 was found to produce the most efficient ablation, ie, removed the greatest volume (mm3) per energy delivered (J) compared to other fluence levels employed (p < 0.0001). Between aortic segments, however, considerable variability in efficiency (mm3/J) was observed, possibly owing to different optical properties and/or plaque composition. Low-intensity laser radiation produced inconsistent ablation and extensive coaylation effects to surrounding tissue. When a fluence of 5.1 J/mm was constructed with a high-intensity laser beam and a short exposure time, consistent and efficient tissue removal resulted without histologic evidence of coagulation necrosis.