The influence of glutaraldehyde on the microscopic structure of human pericardium

•This is the first histological and microscopic study which examines the microscopic collagen structure of the human pericardium in relation to glutaraldehyde (GA) concentration and incubation time.•Independent of the GA concentration, with increasing incubation time the collagen fibers became more compact.•Especially for a concentration of 0.625% GA, typically used in cardiac surgery, prolongation of the incubation has an appreciable effect on the structure of the collagen fibers.•These unchangeable modifications in collagen structures are assumed to promote the calcification process that often causes early (and avoidable?) reoperations.