Next generation catheters for excimer laser coronary angioplasty

In response to the need for maximising debulking in complex lesions, three new excimer laser coronary angioplasty catheter designs have been introduce d. The eccentric laser catheter features a fibreoptic bundle disposed oppos ite the guide-wire lumen at the catheter tip and a torque mechanism that al lows the user to rotate the fibre bundle toward the lesion mass. Residual l umens 50% larger than the catheter tip diameter have been obtained when mul tiple passes were made, with each pass performed using a different tip rota tion. A recent case series utilising this catheter in restenosed stents res ulted in larger lumens and lower B-month restenosis rates. The optimal spac ed (OS) laser catheter features a fibre bundle placed concentrically around the guide-wire lumen. The 61 mum diameter core fibres are spaced at a nomi nal centre-to-centre distance of 90 mum, resulting in a 40% increase in abl ative area as compared to previous concentric catheter designs. In vitro te sting and clinical evaluation demonstrated OS catheters routinely achieve a n ablated area greater than or equal to 90% of the catheter tip size. The 0 .9 mm catheter features a high-density fibre pack composed of 65 fibres. Pe ripheral dead space has been minimised to maximise penetration of calcified plaque. When combined with laser parameters of up to 80 mJ/mm(2). and 80 H z pulse repetition rate, the catheter demonstrated improved hard tissue and calcified tissue penetration in vitro. Clinical evaluation in Canada revea led a 94% lesion recanalisation rate in high-grade stenoses with angiograph ic evidence of calcification, chronic total occlusions, and lesions which h ave failed balloon angioplasty.