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Perspectives of coronary excimer laser angioplasty: Multiplexing, saline flushing, and acoustic ablation control
Author(s) -
Haase Karl K.,
Rose Carsten,
Duda Stephan,
Baumbach Andreas,
Oberhoff Martin,
Anthanasiadis Anastasios,
Karsch Karl R.
Publication year - 1997
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/(sici)1096-9101(1997)21:1<72::aid-lsm11>3.0.co;2-b
Subject(s) - excimer , ablation , excimer laser , laser , materials science , fluence , angioplasty , biomedical engineering , optics , medicine , radiology , cardiology , physics
Background and Objective Bubble formation, pressure wave generation, and cavitations constitute major factors influencing the outcome of clinical Excimer laser angioplasty. Thus, the rationale of this study was to determine the extent of pressure waves occurring during excimer laser ablation and to discuss possibilities that allow a less traumatic plaque removal in the coronary circulation. Study Design/Materials and Methods Conventional and experimental Xenon‐Chlorid‐Excimer lasers emitting light at a wave‐length of 308nm and a pulse duration of 115ns were used for testing of signals. Whereas the conventional excimer laser light source transmits light through all fibres of a 1.7 mm laser catheter simultaneously, the prototype excimer laser divides the laser beam into several areas of uniform energy fluence by scanning the beam from one section to the other using the intermission between two laser discharges. Hydrophones consisting of piezoelectric films detected the acoustic signals, which were obtained on normal arterial wall and atherosclerotic plaque. Results Multiplexing decreases maximum pressures for both normal arterial wall and calcified plaque significantly, whereas pressure rise time remains comparable. During ablation of pure blood, a linear increase of peak pressures of 1 MPa at 10 mJ/mm 2 to 7.5 MPa at 50 mJ/mm 2 is found. Contrast media intensifies the extent of pressure wave formation. At 20 mJ/mm 2 , 60% contrast media added to blood results in an increase of maximum pressures from 1.5 MPa up to 5 MPa. Dilution with saline solution is effective; however, high concentrations of > 90% are required to achieve a significant pressure wave reduction. Conclusion Peak pressures of several thousand kPa occur during excimer laser ablation of contrast media, blood, calcified plaque, and normal arterial wall in a decreasing order. Multiplexing and saline flushing are capable of reducing the intensity of the generated acoustic signals during tissue ablation. It has to be taken into consideration, however, that high concentrations of saline solution are necessary to achieve a significant reduction of peak pressures. Lasers Surg. Med. 21:72–78, 1997. © 1997 Wiley‐Liss, Inc.