VASCULAR CONTRACTILE FUNCTION FOLLOWING EXPERIMENTAL EXCIMER-LASER ANGIOPLASTY

The aim of this study was to determine the vasomotor response to in vi vo excimer laser irradiation with regard to laser-induced tissue effec ts. Transfemoral excimer laser angioplasty was performed in the right carotid artery of 11 New Zealand white rabbits. In four additional rab bits (sham group), the procedure was performed without the application of laser energy. Angiography documented vessel dissection in five las er-treated animals. Perforation occurred in one animal. Rings of the t reated artery and controls of the contralateral artery were investigat ed in a contraction chamber. The passive stress-strain relation (PSS) and the maximum contraction force (MCF) after stimulation with noradre naline, serotonin and potassium chloride were determined. The treated vessels had a higher PSS than the control (p=0.05). The MCF was lower in the treated vessels (p<0.05). The contraction force of the sham-ope rated vessels was higher, although statistically not significant, comp ared to the laser-irradiated segments. In a subset analysis, performed to compare vessels with moderate and severe trauma, MCF was significa ntly reduced in vessels with severe laser-induced injury. Experimental in vivo excimer laser angioplasty in this model resulted in heterogen eous structural changes, including dissections and perforation. Post-m ortem assessment of vasomotor response showed no significant differenc e between laser-treated and sham-operated animals. However, the contra ctile function of the target vessel seems to be reduced following exte nsive laser-induced vessel injury.