Mechanism of tissue fusion in argon laser‐welded vein‐artery anastomoses

Abstract

The mechanism of laser vascular tissue welding remains unknown. This study compared the acute tissue response and long‐term healing of sutured and laser‐welded anastomoses of vein segments used to bypass ligated canine femoral arteries. For each procedure, one anastomosis was formed using running 6‐0 polypropylene suture (control), and the other anastomosis was formed using argon laser tissue welding (experimental). The vein grafts were harvested at 4 (n = 2), 8 (n = 1), 12 (n = 1), and 16 (n = 2) weeks, and selected samples were evaluated by histologic examination, electron microscopy, tensile strength testing, and by measuring the formation of [³H]hydroxyproline as an index of collagen synthesis. Examination of successful laser fusions immediately after they were formed showed bonding of collagen to collagen and elastin to collagen. Follow‐up evaluations showed that the precision of tissue apposition affected the rate of healing and tensile strength. Laser‐welded anastomoses demonstrated a progression of healing similar to sutured repairs, with remodeling of fibrous tissue and collagen being the primary component of weld integrity. This study demonstrates that sutured and argon laser‐welded vein‐artery anastomoses heal comparably up to 16 weeks postoperatively, and that laser welding is a satisfactory alternative to sutured anastomoses.