title: Effects of Nd:YAG laser energy on the arterial wall: evaluation of a new contact delivery system.
abstract: Although there has been much recent interest in the application of lasers to arterial occlusive disease, a detailed understanding of the effects of laser energy on vessel walls is lacking. This study compared the effect of a conventional, non-contact delivery system of Nd:YAG laser energy to a contact system using a 600 microns, artificial sapphire tip in eight mongrel dogs. A small section of the luminal surface of the carotid and femoral arteries was exposed to 10 or 15 joules of Nd:YAG laser power and flow was restored in the vessel. The animals were sacrificed at 0, 1, 2, 4, 7, 14, 21, and 30 days and the vessels were removed. The surface area of the laser injury for each artery was quantitated by computerized planimetry and all histologic sections were examined under light microscopy by an independent observer. Transmural necrosis occurred in 64% (20/31) of the non-contact lesions versus only 29% (9/31) of the contact lesions (P less than 0.01). Both types of laser injuries followed a predictable course with initial medial necrosis followed by formation of a fibrin erythrocyte coagulum overlying the lesions at 24 hr. The usual zones of vaporization, coagulation necrosis, and thermal damage were noted with both types of delivery systems, but the contact system resulted in more intimal vaporization. Healing of all lesions was rapid with complete endothelial coverage at two weeks. Thrombosis occurred in only 1 of 32 (3%) arteries, and there were no false aneurysms. Contact delivery of Nd:YAG laser energy produces significantly less transmural injury than does non-contact.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000502:physiology*; D004285:Dogs; D053685:Laser Therapy / Q000295:instrumentation*; D014656:Vascular Surgical Procedures / Q000295:instrumentation*; D014945:Wound Healing