**6.10 Normothermic** *ex-vivo* **heart perfusion**

The procurement process and OCS instrumentation are described in the DCD and DBD heart donor technique.

The study of 5-year DCD outcomes showed no differences in 30-day survival (97% for DCD vs. 99% DBD, p = 1.00) or 1-year (91% for DCD vs. 89% for DBD, p = 0.72). For DCD cohort, there was no differences in MCS use postoperatively (29% in DPP vs. 24% in NRP, p = 0.75) but the NRP cohort was found to have shorter ventilator support compared to DPP group (0.5 days in NRP vs. 1.4 days in DPP, p < 0.01) [52].

## **6.11 "Extended criteria" cardiac donors**

The demand for heart donors continues to increase but the supply has plateaued [1]. The term "extended heart donor criteria" refers to the expansion of the donor pool by using organs outside of standard categories and using the OCS as a tool to access heart function after explant [48].

The EXPAND trial was conducted to evaluate the safety and efficacy of the Organ Care System in assessing and preserving extended criteria donor hearts [53]. Inclusion criteria include donors with anticipated >4 hours of ischemic time or > 2 hours of

ischemic time plus at least one of these following; age > 55 years, 40–50% of ejection fraction (EF), left ventricular hypertrophy, >20 minutes of donor down time. The study demonstrated short-term survival rates were 94.7 and 88% at 30 days and 6 months respectively. The incidence of primary graft dysfunction at 24 hours postoperatively was 10.7% [2, 20, 53, 54].

The limitations of using *ex-vivo* heart perfusion include higher cost compared to the NRP technique and myocardial edema associated with prolonged *ex-vivo* perfusion time, although this effect can be minimized by avoiding unnecessarily high aortic root pressure. Additionally, synchronized pulsatile aortic flow can be used to achieve peak coronary perfusion during the diastolic phase without excessive root pressure [48].
