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Thermal laser probe angioplasty: Influence of constant tip temperature, plaque composition, and probe/vessei diameter ratio
Author(s) -
Vincent G. Michael,
Fox Jolene,
Johnson Michael D.,
Strickland Richard,
Garry Stacey L.,
Hammond Elizabeth
Publication year - 1990
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/lsm.1900100504
Subject(s) - ablation , in vivo , aorta , materials science , internal elastic lamina , perforation , laser ablation , femoral artery , angioplasty , chemistry , laser , artery , anatomy , surgery , medicine , optics , radiology , composite material , cardiology , punching , microbiology and biotechnology , physics , biology
Thermal laser angioplasty uses constant laser power, producing widely variable tip temperatures in vivo. Results have been sub‐optimal. We studied the effect of 50–400°C tip temperatures on depth of ablation at 192 sites on plaqued and normal human aorta in vitro, and the angiographic and histologic response in vivo of 300–400°C at probe/vessel ratios of 0.5–1.0, in 40 normal canine femoral artery segments. In vitro, there was a direct relationship between tip temperature and depth of ablation, r = 0.71 (all segments), r = 0.74 for fibrous plaque, but a poor correlation in fatty plaque r = 0.35. In fibrous plaque, there was proportionately more ablation at tip temperatures >300°C, mean depth 0.62 mm, than at 150–300°C, mean 0.37 mm, ( P <.001). Ablation was similar in plaqued and normal aorta. In vivo, 300°C, 350°C, and 400°C produced similar effects. At probe/vessel ratios <0.8, only disruption of internal elastic lamina was observed. At ratios ⩾0.8, spasm occurred in 39% (7/18), transmural damage in 28% (5/18), and perforation in one of 18. Ablation is not selective for plaque and is highly variable in fatty plaque. Tip temperatures above 300°C produce greater ablation than at lower temperatures. In clinical applications, probehessel rations ⩽0.7 may be most appropriate, and it appears that thermal remodeling may contribute more to outcome than plaque ablation.