Facilitating the improvement and enlargement of the donor pool in cardiothoracic transplantation

Heart and lung transplantation have become established treatment options
for selected patients suffering from refractory end-stage heart and lung failure.
However, the number of transplantations is limited due to the limited availability
of suitable donor organs.
In the cardiothoracic donor pool two subtypes of donation procedures are
distinguished. One being donation after circulatory death (DCD) and the other
being donation after brain death (DBD). With regards to organ preservation, the
principal difference between a DCD and a DBD donor is that in the DBD donor
both ventilation and blood circulation through organs are maintained up to the
initiation of preservation of the organs. DBD organs are therefore not subjected to
warm ischemic injury. In the DCD donor, the ventilation and blood circulation are
already stopped prior to the initiation of preservation as a result of a withdrawal
of life-sustaining therapy. With that, the organs are subjected to warm ischemia.
The lungs are relatively tolerant to ischemia, whereas the heart is highly vulnerable
to it. As a result of these characteristics, lungs and hearts encounter a different
impact of a DBD or a DCD donation procedure. In turn, the technique used for
preservation and the necessity to evaluate the organ ex situ after the donation
procedure are dependent on both the donor organ and the donor type. Both ex
vivo lung perfusion (EVLP) and ex situ heart perfusion (ESHP) play a key role in
facilitating the enlargement and improvement of the donor pool, as a preservation
technique, but also as a platform for functional assessment.
The overall aim of this thesis was to explore and describe strategies to improve and
enlarge the cardiothoracic donor pool. More specifically, the studies were designed
to 1) describe and evaluate the implementation of both DCD lung transplantation
and EVLP, 2) explore the potential of DCD heart donation for increasing the donor
pool and 3) develop an ESHP strategy that facilitates preservation and assessment
of donor hearts.