title: Large laser sheaths for pacing and defibrillator lead removal.
abstract: OBJECTIVE
  In a recent clinical trial, the 12-F laser sheath showed 95% success in completely explanting chronically implanted pacing leads smaller than 7.5-F diameter. For larger leads, two new sizes of laser sheath have been implemented, the 14-F and 16-F (outer diameter) devices, which accommodate leads up to 9.5- and 11.5-F, respectively. The object of this study was to determine the cutting ability of the larger devices compared to the 12-F design.
  
  
  METHODS
  The rate of device advancement through fresh porcine aorta was measured for three sizes of laser sheath as pulsed ultraviolet light from a 308-nm XeCl excimer laser was applied. Dependent variables were fluence (mJ/mm2), laser pulse repetition rate, and pressure applied between the device and the tissue.
  
  
  RESULTS
  At 60 mJ/mm2, 40 Hz repetition rate and 1.4 kg/cm2 pressure, all devices produced cutting rates in the range of 9-13 microns/pulse. Improvement in advancement per laser shot can be attained by increasing any independent variable studied.
  
  
  CONCLUSIONS
  Physicians must apply only slightly greater force to the larger laser sheaths, and maximum available repetition rate and fluence implies maximum cutting speed.
authors.affiliation: Spectranetics Corporation, Colorado Springs, Colorado 80907, USA.
authors.forename: C
authors.initials: C
authors.lastname: Reiser
authors.forename: K D
authors.initials: KD
authors.lastname: Taylor
authors.forename: R A
authors.initials: RA
authors.lastname: Lippincott
mesh_terms: D000818:Animals; D001011:Aorta / Q000601:surgery; D004567:Electrodes, Implanted; D004867:Equipment Design; D005547:Foreign Bodies / Q000601:surgery*; D053685:Laser Therapy / Q000379:methods*; D010138:Pacemaker, Artificial; D013499:Surface Properties; D013552:Swine