Indocyanine Green Dye Enhanced Vascular Welding With the Near Infrared Diode Laser

Abstract

For vascular anastomosis, use of topical photosensitizing dye enhances selec tive delivery of laser energy to target tissue, thus reducing the amount of collat eral thermal injury and threshold power required for welding. The authors compared the threshold power density needed to weld abdominal aortotomies in rabbits with and without photosensitizing dye. With continuous wave diode la ser energy, the threshold for welding using the dye indocyanine green (ICG) was 150 mW (power density 4.8 watts/cm² at spot diameter of 2 mm). Without dye enhancement, tissue effects were not observed even at the highest energy output available from the laser (300 mW, power density 9.6 watts/cm²). Immediately after welding, the mean bursting pressure for the welds was 260 mm Hg. In survival studies, no anastomotic ruptures, thomboses, or aneurysms were iden tified. Use of photosensitizing dyes for tissue welding is feasible and may allow arterial welding with lower power laser systems and cause less thermal trauma by lowering threshold power levels.