1. Sampling method: the heart valves may be contaminated during recovery, thus at the surface of the tissue. Therefore, testing of the collection and storage media is important. Pieces of tissue for testing must be taken without compromising the function, therefore samples are not representative.
2. In general, the processing takes 3 - 5 hours including dissection, evaluation and antibiotic treatment and final packaging.
3. Only an antibiotic cocktail can be used for decontamination as more robust treatments would compromise the viability of the tissue.
4a. Vital cells may be present as well as small vessels.
4b. Heart valves are used as durable implant, relatively small but implanted in a highly vascularised central site.
5 Total score is 31 for cryo-preserved heart valves, therefore processing in an A with a B background would be indicated. However, it is noted that this analysis would need to be carried out by each centre, considering its own protocols and risk reduction measures.