[Experimental results of excimer-laser-PTA in an experimental ex vivo vascular model]

To evaluate parameters and characteristics of excimer-laser-angioplasty on ex-vivo vessel models.

450 tissue ablations were performed on pig aortas, human arteries and fibrin-fixed plaque material. A pulsed 308nm-XeCl-laser delivering 120 ns pulses was tested. Ablations were analysed depending on frequency (10-40 Hz), energy density (30-70 ml/mm2), catheter-material-angle (0-90 degrees) and object-catheter-distance (0-40 mm).

Vessel recanalisation speeds of up to 0.5 mm/s were achieved on fibrosed to slightly calcified human vessel models. In perforation tests on normal to slightly fibrosed human vessel walls and vessels of pigs ablation speeds of 0.01-0.5 mm/s were measured. Perforations on calcified vessels were successful in 50% of cases after two minutes application time. Vessel perforations were not detected without the support of mechanical power. At catheter-material angles < or = 30 degrees a minor damage of the intima could be found. There was no evidence of necrosis or coagulation in our studies.

In-vitro tests of human plaque material yield reproducible vessel recanalisation distances of up to 25 mm at a variable speed from 0.1-0.2 mm/s.