Factors influencing successful outcome in the arteriovenous loop model: a retrospective study of 612 loop operations.

The arteriovenous (AV) loop is a complex model and requires advanced microsurgical skills. After several years of studies including characterization of the physiological and molecular phenomena behind the process of neovascularization, we would like to evaluate our experience from a microsurgical point of view. The AV loop operation was performed in 612 male Lewis rats. Species, surgeon, previous microsurgical skills, solid or soft consistency of matrix, weeks from implantation to explantation, experience, and practice of surgeon as well length of operation and outcome (patent versus thrombosed) upon evaluation were analyzed for each loop operation. Previous microsurgical skills, matrix, and explantation interval were not significant predictors. There was a significant correlation of experience, practice, and individual performance of microsurgical technicians with the rate of thrombosis and duration of the procedure. Experimental microsurgical operations on animals are best performed by especially trained technicians, rather than microsurgeons working parallel to their clinical activities. The AV loop is an excellent model in the arena of translational technologies, but due to its complexity is unsuitable for screening purposes. Experience and practice are both significant predictors of successful outcome. Possible applications of the model for research purposes are discussed.