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OBJECTIVE: Traditional hand sewing and knot tying have been used for coronary artery bypass grafting (CABG). Although distal suture devices have been applied to facilitate an easier anastomosis in limited cases, such as endoscopic or robotically assisted CABG, almost all these devices were withdrawn from the market for various reasons. We developed a new distal suture device, which allows a continuous suture and eliminates knot tying. We examined safety, feasibility and durability of this device in animal models.
METHODS: This new device comprises a regular 8-0 polypropylene suture attached to a tiny anchor mechanism made up with biocompatible stainless steel at the tail. This patented stainless steel anchor works as a stop mechanism at the start point and as a hooking mechanism at the end of a continuous anastomosis, thus eliminating knot tying. Stability of anastomosis and tissue invasiveness were tested in a rabbit carotid artery bypass model (acute, 1 month, 3 months and 6 months). Off-pump CABG using bilateral internal thoracic artery model in miniature pigs has been tested for preclinical feasibility study, focusing on quality of anastomosis, inflammatory change induced by the device and biocompatibility (acute, 1 to 6 months). All animals received humane care according to the guidelines of the University of Tokyo.
RESULTS: Rabbits were divided to two groups: the new device and conventional 8-0 polypropylene suture. Suture time was not different between groups. Graft patency rate by angiography after 1 month, 3 months and 6 months was favorable and identical between two groups. Histopathologic examination revealed only mild inflammatory responses at the anastomotic sites in both groups without any specific inflammatory change derived from the device. Pigs were divided to two groups as in rabbit models. There were no difference in suture times, graft flow, and patency rates in acute and late phases up to 3 months between groups.
CONCLUSIONS: Safety, feasibility and durability of this new anastomotic device were shown in animal models. This device may be a promising distal suture device for CABG in endoscopic and robotic assistance as well as a regular open situation.