Interactive Determinants for Optimized Stabilization of Autologous Vascular Grafts During Surgery

Abstract

Background: Autologous veins are commonly stored briefly prior to implantation for vascular reconstructive surgery. Several factors have previously been demonstrated to influence the quality of vein grafts during vein preparation for arterial bypass procedures, including the dissection technique employed, the solution used, the distension pressure, the presence of pharmacologic agents, and the temperature of the solution. Moreover, clinical studies have documented the sensitivity of vein segments to handling, temperature, and the solution employed. This study was designed to evaluate intra-cellular–base and extra-cellular–base versions of a new tissue storage solution (Unisol™) at temperatures selected on the basis of the contrasting degrees of hypothermia and practical convenience in the clinical arena (ambient versus refrigeration). Methods: Smooth muscle/endothelial cell physiology was used to compare fresh rabbit jugular veins with veins stored in the experimental Unisol solutions, Viaspan (UW solution), saline, and autologous blood for varying periods of time (1, 3, or 24 h) at either 25°C or 4°C. A factorial analysis of variance was used in the design and analysis of the study to evaluate the interaction of solution composition with time and temperature as major determinants of vein preservation. Results: Optimum preservation of veins was achieved by selection of the type of storage medium in relation to time and temperature. Synthetic preservation solutions were clearly shown to be better than commonly used blood or saline. The rank order of the solutions after brief storage (1 h) at 4°C, in terms of both contractile and relaxation responses, was Unisol > UW > saline. Physiological responses were significantly better after storage in Unisol (p < 0.001), but not the UW solution, compared to saline as the clinical reference solution. Conclusion: The important conclusion from the analysis of variance is that Unisol was found to be better than blood or saline under all conditions at both 3 and 24 h.Unisol is proposed as a baseline solution formulation for the storage of vascular grafts. Further optimization by the incorporation of additional cytoprotective additives and testing in vivo is planned.