Microvascular end-to-side arterial anastomosis using the Nd: YAG laser.

End-to-side, laser-assisted vascular anastomosis (LAVA) using a Nd: YAG laser was successfully performed on rat carotid arteries. A midline neck incision allowed isolation and approximation of both carotid arteries in an end-to-side fashion using four 10-0 nylon stay sutures. The laser parameters used for vessel fusion were 0.3-second 5-W pulses at a spot size of 600 microns. Anastomoses were analyzed at various time intervals from 1 day to 6 months by angiogram and histological examination. The anastomotic patency was 86%. Aneurysm formation occurred in 23%. Histological examination revealed an acute/subacute transmural injury both at the anastomotic site and several hundred microns away, with delayed re-endothelialization and some attempt at muscular and elastic regeneration. Histological assessment of the aneurysms demonstrated a total loss of the internal elastic lamina and muscularis. A brief discussion comparing Nd: YAG LAVA to other LAVA techniques follows.