Nd: YAG laser-welded canine arteriovenous anastomoses

This preliminary report describes formation of femoral arterio‐venous fistulas (n = 10) in six dogs using a 1.32‐μm wavelength Nd:YAG laser welding technique. Stay sutures (6‐0 polypropylene) were placed at 5–7 mm intervals along the anastomoses for vessel apposition. Delivery of laser energy through a 400‐μm diameter fiber optic was controlled by a new computer‐based software system. At 3 mm distance above the anastomosis, energy fluences of 110–260 J/mm2/cm length of anastomosis were used for laser welding. One or two additional hemostatic sutures were required in seven of the ten anastomoses. Flow was maintained for 1–2 hours prior to tissue harvesting. No thrombosis or delayed anastomotic failures were observed after initial welding and repair. Histologic examination revealed good apposition and adherence between wall layers and a fibrinous coagulum at the intimal junctions. Mild thermal injury of the wall was present at some anastomoses. This early investigation suggests that a 1.32 μm Nd:YAG laser welding technique can successfully create large vessel arteriovenous fistulas in the canine. © 1994 Wiley‐Liss, Inc.