Restoring Function, Transporting, Assessing and Transplanting the Donation after Circulatory determined Death (DCD) Heart
Creators: name: Messer, Simon Jamie
Publisher: name: Apollo - University of Cambridge Repository
Year: 2019
Subjects: heart
transplant
circulatory death
DCD

description: The demand for heart transplantation currently outstrips the number of suitable hearts available from donation after brain death (DBD) donors. Currently in the United Kingdom (UK) less than half of patients on the heart transplant waiting list are transplanted with a 13% waiting list mortality. The donation after circulatory determined death (DCD) donor has been well established for the transplantation of abdominal organs and lungs with good results. DCD heart transplantation was explored 50 years ago but was soon abandoned due to poor outcomes associated with early immunosuppression. The aim of this study was to determine which method was best to retrieve, transport and transplant the DCD human heart. To begin, a national DCD audit was undertaken, determining whether enough suitable DCD heart donors existed within the UK to justify investment in a national programme. After reviewing over 3,000 donors, 50 potentially excellent DCD heart donors could be identified per year increasing overall heart transplant activity by 30 %. Following this, the best method of DCD heart preservation was explored in the rodent model. Cold static storage, practiced in the UK for other DCD organ retrieval, was compared to ex situ normothermic machine perfusion of the DCD heart. Cold storage was found to be not suitable for the DCD heart preservation due to poor function after 2 hours of storage. After cold storage was eliminated, two techniques of normothermic machine perfusion were explored. Normothermic regional perfusion (NRP) of the heart within the donor was compared to direct procurement and perfusion (DPP) of the donor heart ex situ. After 2 hours of perfusion, left sided function was assessed on a working heart platform and DPP hearts were shown to have superior function. In order to establish DCD heart transplantation within our institution, it was a requirement that DCD heart function be assessed prior to transplantation. In the absence of a commercially available ex situ working heart platform, the feasibility of performing NRP in the human was assessed. In a small human feasibility study, it was shown that DCD hearts could be reanimated and support the donor systemic circulation after weaning from NRP allowing functional assessment. After the technique was shown to be reproducible and safe, the first successful human DCD heart transplant with functional assessment was undertaken. Heart function was found to be excellent following transplantation and following this case a further 9 DCD human heart transplants were performed at our institute. NRP revealed that if the functional warm ischaemic time was kept below 30 minutes, heart function was found to be excellent in the donor following weaning from NRP. After this discovery, we began exploring DCD human heart transplantation using the DPP technique without functional assessment. After undertaking the first 22 DCD heart transplants at Papworth hospital we compared the clinical outcomes of DCD heart transplants against matched heart transplants from DBD donors. There was no difference in clinical outcomes between DCD or DBD, nor any difference in outcomes between hearts retrieved by the DPP or NRP technique. In this study DCD heart transplantation has been shown to be reliable and reproducible, with early clinical outcomes equivalent to that of hearts transplanted from DBD donors. Following this work, national DCD heart transplant roll out has begun in the UK. Challenges of the future include funding such a service, improving ex situ normothermic perfusion to include functional assessment as well as transplanting paediatric DCD hearts.
description: European Society of Organ Transplantation, The Freemasons’ Grand Charity, The Masonic Samaritan Fund, Evelyn Trust, Papworth Hospital Charity, NHS Blood and Transplant and the Gledhill Fellowship.