Laser vascular welding—How does it work?

This study evaluated the histology and electron microscopy of four samples of 2 cm long venotomles and artery-vein anastomoses formed in canine femoral arteries and veins using the argon laser (0.5 W power, 1 800 J/cm², 4 min exposure/1 cm length of anastomosis). Welds were continuously irrigated with saline during the procedure to limit maximal temperatures to 44.2±1.6°C (mean±SD), and the specimens were removed immediately following fusion and preserved for examination. Histologic and electron microscopic examination of different areas of the welds revealed various mechanisms of fusion including a) apposition of denatured collagen and elastin in the media and adventitia; b) bonding of veln medial collagen and elastin to the internal elastic membrane of the artery; and c) fusion consisting of a coagulum of platelets and fibrin depending on the allgnment and apposition of the vessel edges. This study demonstrates that vascular tissue fusion by the argon laser occurs by various mechanisms. Future experiments should delineate which types of seal produce the optimal strength at the time of fusion, and enhance longterm healing. Presented at the 1986 Southern California Vascular Surgical Society meeting, September 26–28, 1986, Long Beach, California. Supported by Grants HL-32622, GM-288833, AM-28450 and AM-35297 from USPHS, National Institutes of Health.