Catheter associated problems of multi-fibre systems in clinical excimer laser angioplasty

We report our experience in 60 patients using a recently designed 4 French ring catheter system for coronary and a 7 French ring catheter for peripheral percutaneous excimer laser angioplasty. The advantages in comparison to bare fibres comprise an improved flexibility and a central channel for insertion of guide wires to minimize the risk of mechanical vessel wall perforation. The peripheral laser catheter initially transmitted overall energies of 20 mJ pulse^–1 (51 mJ pulse^–1 mm^–2), the coronary device 4.5–5 mJ pulse^–1 (32 mJ pulse^–1 mm^–2). A 50% or more decrease of energy transmission was found in 43% of coronary catheters due to a number of blinded fibres with other fibres remaining intact. This was either due to a retrograde expansion of shock waves generated by the excimer pulse at a calcified lesion, or the result of a deleterious back-reflection of the laser light by contrast media. However, using both laser catheters ablation of plaque in vivo proved to be possible. Small mechanical defects of the catheter tips in 27% did not result in patient related complications. Our initial experience favours further improvement of ring catheters for percutaneous excimer laser angioplasty.