Comparative in vitro study of tissue welding using a 808 nm diode laser and a Ho : YAG laser

In vitro porcine arteries and veins have been welded end-to-end using eithe r a 808 nm diode laser combined with an indocyanine green enhanced albumin solder, or with a continuous-wave (cw) Ho:YAG laser without biological sold er. The vascular stumps were approached to each other over a coronary dilat ation catheter in order to obtain a precise alignment and good coaptation. Standard histology revealed for both welding techniques lateral tissue dama ge between 2 and 3 mm caused by laser-induced heat. Good solder attachment to the tissue was observed by the use of a scanning electron microscope. Th e vessels soldered with the 808 nm diode laser using albumin solder showed considerably higher tensile strength (1 N compared to 0.3 N) than vessels w elded exclusively by Ho:YAG laser radiation. In contrast, leaking pressure (350 +/- 200 mmHg) and bursting pressure (457 +/- 200 mmHg) were found to b e independent of the welding technique used. This study demonstrates that f ast (total welding time about 2-5 min), stable and tight microvascular anas tomosis can be achieved with the use of a dye-enhanced albumin laser solder ing technique and an ancillary coronary dilatation catheter.