Experimental arteriosclerosis treated by argon ion and neodymium-YAG laser endarterectomy

The argon ion laser (488 and 514.5 nm) and the Nd-YAG laser (1.06 micron) have been used in most studies of laser radiation for treatment of arteriosclerotic cardiovascular disease because their beams can be directed through a delivery fiber. We compared the effects of argon ion and Nd-YAG lasers in vivo on arteriosclerotic rabbit aortas with open laser endarterectomy. A thoracoabdominal exploration was performed in 16 rabbits to isolate the aorta. Laser beams were directed through delivery fibers to produce a line of laser craters at the proximal and distal ends of an atheroma. The lines of laser craters were connected by continuous-wave laser radiation to loosen the plaque and the cleavage plane was developed within the media by continuous-wave laser radiation. End points were fused by continuous-wave laser radiation and the aortas were harvested for light and scanning electron microscopy. Argon ion laser endarterectomy (eight rabbits) required an energy density of 98 +/- 19 J/cm2. Nd-YAG laser endarterectomy (eight rabbits) required an energy density of 1147 +/- 129 J/cm2. Perforation did not occur with the argon ion laser but occurred in six of eight Nd-YAG experiments. Even depths of plaque removal resulted from argon ion laser endarterectomy but not from Nd-YAG laser endarterectomy. Gross and microscopic grading of the aortas showed that argon ion endarterectomy surfaces were significantly better than Nd-YAG surfaces (p less than .05). Similarly, argon ion end points were significantly better than Nd-YAG end points (p less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)