Potential use of holmium lasers for angioplasty: Evaluation of a new solid-state laser for ablation of atherosclerotic plaque

✍ Scribed by Karl K. Haase; Andreas Baumbach; Manfred Wehrmann; Stefan Duda; Giulio Cerullo; Benno Rückle; Erwin Steiger; Karl R. Karsch

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 573 KB
• Volume: 11
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/lsm.1900110306

✦ Synopsis

Tissue effects of the mid-IR Holmium laser (emitting at a wavelength of 2130nm) were evaluated. This wavelength is attractive because it combines high water absorption and easy transmission through standard optical fibres. The laser was pulsed with pulse durations in the range of 100psec and repetition rates between 2 and 6 Hertz. For all experiments a repetition rate of 2 Hertz was used. The laser beam was coupled into waterfree quartz fibers with core diameters of 200 and 800pm with an efficiency of 70 and 80%, respectively. Ablation of atherosclerotic plaque has been performed at an ablation threshold of 10Jkm2 for the 800p.m and 40J/cm2 for the 200pm fibre. Removal of calcified plaque was possible. Ablation efficiency increased in a non-linear fashion with increasing pulse energies. The ablation rate per pulse was approximately 2mm at energy fluences of 1000J/cm2 for the 200pm fibre and 1.25mm at energy fluences of 70J/cm2 for the 800pm fibre; a further increase in energy densities did not result in higher ablation rates. On macroscopic examination only very limited thermal injury was found in crater adjacent tissue structures. Crater edges were even and did not reveal signs of crater charring or debris in the crater lumen. However, the histologic specimens revealed zones of thermal damage extending 100 up to 1000pm lateral into adjacent tissue. Thermal damage increased with increasing radiant exposures and depended on the medium used.