Selective laser photocoagulation of blood vessels in a hamster skin flap model using a specific ICG formulation
✍ Scribed by Mordon, Serge; Desmettre, Thomas; Devoisselle, Jean-Marie; Mitchell, Valérie
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 344 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0196-8092
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✦ Synopsis
Background and objective:
The present study was undertaken to evaluate the selective laser photocoagulation of blood vessels in a hamster skin flap model using a specific indocyanine green (icg) formulation.
Study design/materials and methods:
Experiments were performed in a hamster skin flap model after injection of icg in aqueous solution (icga), or after injection of a specific formulation of icg (icg in emulsion: icge). laser irradiation was achieved 30 minutes after injection with a 300 microns fiber connected to a 805 nm diode laser (power = 0.8w, spot diameter = 1.3 mm and pulse exposure time lasting from 1 to 5 s). macroscopic observation and acute histology were performed to compare the tissue effects obtained for each icg formulation and to assess the selectivity of vessel damage.
Results:
The icge clearance process was slowed down as compared to the icga process. after 30 minutes, the concentration of icg in blood is higher (2.27 +/- 0.4, p < 0.003) for icge compared to icga. with icga, vessel coagulation required a minimum fluence of 240 j/cm2, which led to very significant skin damage. conversely with icge, vessel coagulation required a fluence of 120 j/cm2. with such a fluence, no laser effect could be detected on the skin. histological examination confirmed blood vessels coagulation in depth, whereas epidermis and dermis remained intact.
Conclusion:
The major restrictions of icg in aqueous solution, which are the very-short half-life of icg in blood and consequently the lack of selectivity in blood vessels after a few minutes, are alleviated when icg is used in emulsion. icg in emulsion increases the circulating half-life of icg and moreover confines icg in the vascular compartment. thanks to this specific property, it is possible to obtain a selective vascular damage 30 minutes after injection.