Factors affecting the yield of cardiac valve allografts from living unrelated donors.

OBJECTIVE

Allografts are the valve of choice for fertile women, patients with infective endocarditis and those with small aortic roots. However, the supply of valves is problematic and widespread usage is restricted by limited availability. Allograft valves are available from cadaveric donors and from the explanted hearts of transplant recipients. Potentially, hearts from these patients could be an excellent source of usable aortic and pulmonary valves. However, little information is available on the suitability of such donors, the procurement rate of allograft valves from this source, or the factors that limit the yield of implantable valves from explanted hearts.

METHOD

In order to examine some of these issues, we have carried out a retrospective study on the explanted hearts offered to the East Anglian Tissue Bank by Papworth hospital. Papworth hospital carries out approximately 90 heart and heart/lung transplants per year. Over a 2 year period, the tissue bank was offered 72 hearts from this programme.

RESULTS

Of the 72 hearts offered, 58 were accepted for subsequent dissection and further examination. A total of 14 hearts were refused. The main reasons for refusal were extensive cardiectomy trauma (4 hearts) and abnormal valve morphology (four hearts). Of the 116 valves from those hearts accepted for dissection, 55 valves were rejected upon further examination. Reasons for rejection included: cardiectomy trauma (26 valves), abnormal morphology (22 valves), procurement/dissection trauma (7 valves). Of the 61 valves banked, four were subsequently rejected due to positive or incomplete microbiology. Procurement trauma fell to 0% in the last 12 months of the study but cardiectomy trauma remained constant and was related to previous cardiac surgery. Overall, the yield of implantable valves was 0.8 valves/donor. However, the yield showed considerable variation, from 1.0 valves/donor for donors diagnosed as cardiomyopathy to 0.5 valves/donor for donors with ischaemic heart disease who had undergone previous cardiac surgery.

CONCLUSION

It is possible to predict the likely yield of explanted heart valves from different groups of heart transplant recipients, based on diagnosis and previous history. The yield of usable valves could be increased by avoidance of injury, both during cardiectomy and subsequent removal of the valves; this is achievable through appropriate training.