Gas production in tissue phantoms and tissue by XeCl excimer laser: effect of beam delivery system geometry

In excimer laser coronary angioplasty (ELCA) an XeCl excimer laser at 308 nm is used to ablate atherosclerotic plaque in a stenosed coronary artery. In previous experiments we have seen that during ablation of cardiovascular tissues under saline, there is always a release of a stream of insoluble gas bubbles. We believe that this gas plays a crucial role in the understanding of the recanalization process in ELCA where a laser beam delivery catheter is brought in contact with the plaque in a tight space. It is well conceivable that the gas may help to recanalize an artery as a kind of dottering effect but especially in a tight stenosis the gas accumulation may enhance the damage to the vessel wall. The aim of the study was to investigate the dependency of the gas production by a XeCl excimer laser on the energy density and the diameter of the beam delivery system, to establish whether the effects of gas could be minimized or would be independent on the beam delivery system.