Tissue soldering by use of indocyanine green dye-enhanced fibrinogen with the near infrared diode laser

Anastomoses welded by laser have been strengthened by applying a solder of fibrinogen combined with a laser energy absorbing dye (indocyanine green, maximum absorbance 805 nm) to the anastomotic site before continuous-wave diode laser exposure (808 ± 1 nm, 4.8 W/cm²). Immediately after creation, the bursting pressures of welds created without fibrinogen (262 ± 29 mm Hg, n = 11) were significantly less than repairs with fibrinogen (330 ± 75 mm Hg, n = 11) (p < 0.05). When repairs performed with fibrinogen were exposed to urokinase (25,000 IU) the bursting pressures were not significantly different from baseline (290 ± 74 mm Hg, n = 5). Aortotomies closed by suture did not burst but leaked at pressures significantly below those of vessels closed by laser (165 ± 9 mm Hg, n = 11) (p < 0.01). Twenty-two repairs soldered with fibrinogen were incorporated into survival studies in rabbits and examined from 1 to 90 days after operation. No anastomotic ruptures, thromboses, or aneurysms were identified. Soldered sites rapidly regenerated a new intimal surface and healed by myofibroblast proliferation. No significant foreign body response was identified; the fibrinogen was resorbed. Laser soldering with exogenous fibrinogen is feasible without topical administration of additional clotting agents, significantly improves the bursting strength of primary laser welded anastomoses, and appears to result from urokinase-resistant fibrinogen cross-linking.