[In vitro effects of argon laser radiation the human healthy and atherosclerotic aorta]

Argon laser exposures in vitro were done on human aortas. The laser energy applied on a fresh aorta section (A) was from 100mw to 1000mw. A second aorta section (B), formalin fixed, was irradiated under saline solution by a fiberoptic system. Laser energy was from 400mw to 720mw. The time exposures were all different in both sections. A and B histologic findings of thermal damage were similar Three zones of tissue injury were observed: I) crater because of tissue vaporization; II) coagulative necrosis surrounding it; and III) multiple vacuoles in the adjacent tissue produced by acoustic or shock injury. Tissue damage was related directly with total energy delivered: less than or equal to 500mw showed inner vascular wall necrosis, and at greater than or equal to 720mw it was perforated. Atherosclerotic tissue was more resistant to laser thermal injury than normal tissue. We could not find time relation with thermal damage. This preliminary information is an early step for the possible use of Argon laser on cardiovascular area.