Pathologic findings in post-surgical vascular access button (VAB) complications in rats

ACVP 2023 -- The introduction of vascular access button (VAB) devices has increased the availability and efficiency of long-term direct vascular access for preclinical research in multiple species. Life-limiting complications from their implantation and usage is rarely reported in the literature. This case series describes post-implantation complications in Wistar Han� rats implanted with dual-vascularized (jugular and femoral vein) VABs by a commercial supplier (Supplier A). In multiple sequential cohorts, up to 69% of rats presented with surgical site dehiscence, ulceration and abscessation within 1 to 30 days of facility arrival, with 27-50% of each cohort presenting within the first 3 days of arrival. Similar clinical outcomes occurred with two different commercially available VAB devices implanted by Supplier A. The use or omission of intra-wound surgical glue used by Supplier A to secure the felt pad anchor had no effect on clinical outcome. Histologically, affected button sites were characterized by severe ulceration and dermal necrosis under the protective cap, necrosis of scaffold tissue in the polyester felt pad used for anchoring, and colonies of mixed bacteria concentrated around the port tract. These changes were compared to button sites observed in rats implanted with the same VAB devices by a different commercial supplier (Supplier B). In these animals, clinical evidence of post-surgical complications was rare and histologic evaluation revealed intact felt pads with minimal to no epidermal or dermal lesions. Differences in supplier surgical technique, immediate post-operative care, and transport conditions were considered the most likely factors in the development of severe post-surgical complications in VAB-implanted button devices.