Pneumoperitoneum and steep Trendelenburg position significantly increase MAP and SVR. Trendelenburg position increased stroke volume. Pneumoperitoneum decreases aortic diameter. No significant changes in cardiac output or stroke volume were noted.

We have studied laser radiation of arteriosclerotic cardiovascular disease to determine the best technique for evaluation. Rabbits with arteriosclerosis were treated by intraluminal laser angioplasty (N = 8), laser angioscopy (N = 2), and open laser endarterectomy (N = 5 ) . All studies were performed with an argon ion laser delivering energy through a 400-pm quartz fiber. Power delivered was varied in order to determine the best value for this animal model. Following angioplasty, perforation was seen in three rabbits (in one case, it was due to mechanical trauma from the fiber optic), and early thrombosis occurred in two rabbits. Plaques were vaporized by angioscopy, but the depth of laser beam penetration or angle of incidence could not be controlled. Open laser endarterectomy gave consistently good results with removal of an arteriosclerotic plaque within the media. The optimum power was found to be 1.0-2.0 W. Endarterectomy required an energy density of 100-140 J/cm2. We conclude that open laser endarterectomy can be a standardized technique for the in vivo evaluation of laser radiation upon arteriosclerotic lesions.

Open laser endarterectomy was compared to standard surgical endarterectomy in the rabbit arteriosclerosis model. The aorta was exposed by a thoracoabdominal exploration in 16 rabbits. In Group I (8 rabbits), a conventional endarterectomy (CE) was performed with standard vascular instruments. In Group II (8 rabbits), laser endartercctomy (LE) was performed with an argon ion laser (488 nm and 514.5 nm) at a power of 1.0 W. Aortas were fixed, serially sectioned (6 pm) and stained (H + E) following each procedure. Gross and light microscopic examination revealed identical results for the endarterectomy surfaces of CE and LE. The proper cleavage plane within the media was developed with both techniques and the remaining arterial wall was not damaged with either procedure. The end points of LE were consistently superior to those of CE because of phototherapy fusion. The LE end points were tapered and the intima was fused. Intimal flaps were seen in 2/8 CE experiments and the remaining end points exhibited an uneven transition. LE required an average energy density of 124 + 9 J/cm*. We conclude that LE provides a satisfactory method for the in vivo evaluation of laser radiation upon arteriosclerotic arteries. LE may be the way to begin clinical laser trials. o 1985 Academic Press Inc.