A survey of 24 international heart valve banks was conducted to acquire information on heart valve processing techniques used and outcomes achieved. The objective was to provide an overview of heart valve banking activities for tissue bankers, tissue banking associations, and regulatory bodies worldwide. Despite similarities found for basic manufacturing processes, distinct differences in procedural details were also identified. The similarities included (1) use of sterile culture media for procedures, (2) antibiotic decontamination, (3) use of dimethyl sulfoxide (DMSO) as a cryoprotectant, (4) controlled rate freezing for cryopreservation, and (5) storage at ultralow temperatures of below ？135°C. Differences in procedures included (1) type of sterile media used, (2) antibiotics combination, (3) temperature and duration used for bioburden reduction, (4) concentration of DMSO used for cryopreservation, and (5) storage duration for released allografts. For most banks, the primary reasons why allografts failed to meet release criteria were positive microbiological culture and abnormal morphology. On average, 85% of allografts meeting release criteria were implanted, with valve size and type being the main reasons why released allografts were not used clinically. The wide variation in percentage of allografts meeting release requirements, despite undergoing validated manufacturing procedures, justifies the need for regular review of important outcomes as cited in this paper, in order to encourage comparison and improvements in the HVBs’ processes. 1. Introduction Since the first heart valve bank (HVB) started in New Zealand in 1962, the recovery, processing, and storage techniques have been constantly evolving to improve the quality and safety of cardiovascular allografts for clinical implantation. During the initial era of allograft usage, fresh aseptically recovered allografts were implanted within hours or days of recovery. This was followed by aggressive decontamination methods, such as gamma-irradiation and chemical sterilisation using formaldehyde, glutaraldehyde, beta-propiolactone, and ethylene oxide. Coupled with harsh preservation techniques of freeze-drying and flash-freezing in liquid nitrogen, these “sterilised” tissues rapidly failed in situ due to high incidence of leaflet degeneration, cusp rupture, and/or loss of durability and hemodynamic function. For these reasons, allograft use was discontinued until newer preservation methods were developed. Eventually, “sterilised” tissues were replaced by aseptically recovered ones treated with
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