Intraluminal laser light source and external solder: in vivo evaluation of a new technique for microvascular anastomosis

BACKGROUND AND OBJECTIVES: Current laser-assisted end-to-end anastomoses are performed by irradiating the vessel wall from outside after additional fixation with three to six sutures. These sutures are needed to provide adequate approximation of the vessel stumps. We present a new laser soldering technique that is based on an intraluminal laser light source centered in a balloon catheter, and external application of a solder. This technique was applied in vivo in order to test its feasibility under clinical conditions. STUDY DESIGN/MATERIALS AND METHODS: Seven white pigs were treated with a total of fourteen end-to-end laser-anastomoses of their saphenous arteries having outer diameters of 2 mm. The vessels were stented over an intraluminal balloon catheter, which was maximally dilated and which allowed for a precise approximation of the vascular stumps. An 808 nm diode laser was coupled into a specially designed optical fiber producing a 360 degrees radiation ring inside the balloon catheter. An indocyanine green (ICG) doped liquid albumin solder was applied on the external surface of the vascular stumps. Laser soldering was achieved by irradiating with a 808 nm laser diode for 75 seconds. Tightness of the anastomoses was evaluated by clamping the artery distal to the anastomosis for 1 hour, and patency was tested over an observation period of 3 hours, during which the animals were heparinized. Thereafter, the anastomoses were harvested for histomorphological examination. RESULTS: All anastomoses remained patent over the entire observation period. Some leakage was observed in three anastomoses, which was explained by a deviation of the illumination fiber from the center of the balloon leading to an inhomogeneous irradiation of the vessel wall. Histology revealed perfect adaptation of the vascular stumps. A segment of denaturated vascular collagen was observed, that corresponded to the irradiated, solder-covered zone. CONCLUSION: Patent, maximally dilated and well adapted microvascular anastomoses could be obtained without the need of stay sutures. A well centered laser light source is indispensable for avoiding inhomogenous welding, thus causing leakage.