Direct laser and laser-thermal irradiation of normal canine coronary arteries: implications for laser delivery...

Clinical use of laser recanalization has been mostly limited by arterial perforation. Two modifications of the optical fiber were used to decrease the perforation rate: (1) a guidewire to align the fiber in a coaxial position with the vascular lumen and (2) encapsulation of the optical fiber tip with a metal cap. Fourteen dogs were studied. Argon laser radiation was delivered through optical fibers, 9 with a 1.7-mm metal encapsulated fiber (Laserprobe-PLR,¿ Trimedyne, Santa Ana, CA) and 5 with a 2-mm metal encapsulated fiber with a window at the tip (Spectraprobe-PLR). Three dogs served as control, and no guidewire was used. In 11 dogs, laser irradiation was done either in advancing the probe or on pullback over a guidewire. Energy used ranged from 25 to 50 J. In vitro, this raised the probe temperature in blood to a maximum of 500 degrees C. Arterial perforation occurred in 2 of 4 lased arteries without guidewire (p less than 0.05). There was no difference in perforation rated comparing the Laserprobe (1 out of 17 arteries) and Spectraprobe (1 out of 8 arteries) (p greater than 0.05). At high laser energy (50 J), there was an increased incidence of thrombus formation, which appeared to be associated with adherence of the metal cap to the arterial wall (3 out of 6 vs. 1 out of 19, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)