How to counteract the lack of donor tissue in cardiac surgery? Initial experiences with a newly established homograft procurement program.

Homograft heart valves may have significant advantages and are preferred for the repair of congenital valve malformations, especially in young women of childbearing age, athletes and in patients with active endocarditis. A growing problem, however, is the mismatch between tissue donation and the increasing demand. The aim of this paper is to describe the initiation process of a homograft procurement program to attenuate the shortage of organs. A comprehensive description of the infrastructure and procedural steps required to initiate a cardiac and vascular tissue donation program combined with a prospective follow-up of all homografts explanted at our institution. Between January 2020 and May 2022, 28 hearts and 12 pulmonary bifurcations were harvested at our institution and delivered to the European homograft bank. Twenty-seven valves (19 pulmonary valves, 8 aortic valves) were processed and allocated for implantation. The reasons for discarding a graft were either contamination (n = 14), or morphology (n = 13) or leaflet damage (n = 2). Five homografts (3 PV, 2 AV) have been cryopreserved and stored while awaiting allocation. One pulmonary homograft with a leaflet cut was retrieved by bicuspidization technique and awaits allocation, as a highly requested small diameter graft. The implementation of a tissue donation program in cooperation with a homograft bank can be achieved with reasonable additional efforts at a transplant center with an in-house cardiac surgery department. Challenging situations with a potential risk of tissue injury during procurement include re-operation, harvesting by a non-specialist surgeon and prior central cannulation for mechanical circulatory support.

Cryopreserved human heart valve allografts: a ten-year single centre experience.

This study provides an overview of tissue banking activities at the Croatian Cardiovascular Tissue Bank (CTB) during past ten years and presents the outcomes of cryopreserved heart valve allografts (CHAs) use in different patient groups. From June 2011 until December 2021, 75 heart donations were referred to CTB: 41 recipient of heart transplant (RHT), 32 donors after brain death (DBD) and 2 donors after circulatory death (DCD) donations. Processing resulted in 103 valves of which 65 met quality requirements for clinical use. Overall tissue discard rate was 37%. The most frequent reasons for discard were inadequate morphology (12%) in RHT donations and microbiological contamination (19%) in DBD donations. Altogether, 38 CHAs were transplanted to 36 patients. Recipients were divided in three groups; infective endocarditis (IE), non-infectious heart disease and congenital heart disease group. In the IE group, the 30-day, 1-year and 3-year survival was 71%, 53% and 47%, respectively. Freedom from re-operation due to all graft-related causes was 76% and due to structural valve deterioration 88%. There were no cases of graft reinfection. In the congenital heart disease group CHAs were predominantly (94%) used for right ventricular outflow tract reconstruction and 88% of patients recovered without graft-related complications. At present, the number of demands for CHAs at CTB considerably outweighs their availability.

Transplantation of cryopreserved human heart valves in Europe: 30 years of banking in Brussels and future perspectives.

For over 30 years, our TE has processed, controlled for quality and distributed cryopreserved allograft valves for human application. We present a review of this activity and future perspectives of cardiovascular tissue banking. The donor age and medical/behavioral history are in compliance with the regulations of the EUMS. Allograft morphology and function are evaluated in a class A cleanroom. Tests for viral/bacterial infection, histological control of structure/infection/malignancy and control-rate cryopreservation are performed. A total of 7562 hearts were sent to our TE, whereas 7290 valves (pulmonary, aortic and mitral) were transplanted. The donations increased over time: 1934, 2566 and 3062 hearts were donated during the first, second and third decades (increases of 32.7 and 19.3% during the second and third decades). Likewise, there was a significant increase in transplantations with 2050, 2550 and 2690 valves implanted during the first, second and third decades (24.4 and 5.5% increase during the second and third decades). A total of 4475 pulmonary (61.4%), 2760 aortic (37.9%) and 55 mitral valves (0.7%) were transplanted. Outstanding long-term results in adults and evidence of immune-related deterioration of allografts in neonates and infants were demonstrated. Decellularization was suggested as a solution. One hundred pulmonary and 180 aortic valves were sent for transplantation after decellularization for the ESPOIR and ARISE clinical trials and beyond. The donation and transplantation activity increased progressively. Although cryopreserved valves represent the best substitute for diseased valves, accelerated failure appears after implantation in neonates and infants. The implementation of new technologies, such as decellularization, as a standard procedure for treatment of allograft valves will offer further improvements in allograft quality and increase of durability.