Advancements in Organ Perfusion and Preservation
Summary of Medical Lecture by Gabriel Oniscu, MD, FRCS
1. Main Clinical Topics Discussed
- The rationale and clinical necessity for machine perfusion technology in organ transplantation
- Current perfusion modalities in liver transplantation, with emphasis on Donation after Circulatory Death (DCD) donors
- Normothermic Regional Perfusion (NRP) and its clinical outcomes
- Hypothermic Machine Perfusion (HMP) and Normothermic Machine Perfusion (NMP)
- Organ utilization challenges and strategies to reduce discard rates
- Future directions in organ assessment, viability testing, and repair
2. Key Learning Points, Guidelines, and Recommendations
- DCD donation has become the primary pathway to donation in several European countries, now representing 40–60% of the total donor pool in Belgium, the Netherlands, and the UK
- Machine perfusion technology addresses the compounded injury of warm ischemia followed by cold ischemia inherent to DCD donation
- Currently validated clinical perfusion strategies include:
- Normothermic Regional Perfusion (NRP / aNRP / tNRP) — applied in situ in the donor
- Hypothermic Machine Perfusion (HMP / HOPE)
- Normothermic Machine Perfusion (NMP)
- Controlled oxygenated rewarming (HOPE → NMP)
- Technology selection should be guided by the clinical objective: extended preservation, viability assessment, or organ repair
- Increasing temperature during perfusion increases potential benefit but also increases device complexity and management risk — a balance must be maintained
- NRP should be considered the preferred first-line strategy for DCD donation, given its multi-organ benefits and strong outcome data
3. Specific Clinical Data, Statistics, and Study Results Cited
- Organ discard rates in DCD donors remain significantly and consistently higher than in DBD (Donation after Brain Death) donors, with substantial inter-OPO variation in risk acceptance in the US
- Ischemic cholangiopathy (IC) in DCD liver transplantation:
- Historical rate without NRP: ~25–30%
- With NRP (European series): reduced to single digits
- Comparison with DBD controls: NRP-treated DCD livers now demonstrate equivalent biliary complication rates
- US multicenter study (San Diego group, n >100): zero cases of ischemic cholangiopathy with NRP
- European meta-analysis (publications to ~2022): NRP associated with significant improvement in:
- Early allograft dysfunction
- Anastomotic biliary strictures
- All-cause biliary strictures
- Ischemic cholangiopathy
- Kidney transplantation outcomes with NRP (US data):
- 10-fold increase in DCD kidney transplants over two years
- Significant reduction in organ discard
- Significant reduction in Delayed Graft Function (DGF)
- Post-transplant outcomes (liver, up to 1 year):
- Reduced morbidity and mortality
- Fewer hospital readmissions
- Reduced need for MRCP, liver biopsy, and contrast-enhanced CT
- Lower retransplantation rates
- UK data (Cambridge and Edinburgh): Centers using NRP reported a substantial reduction in ICU stay, reflecting cost savings at the institutional level
- NRP duration: approximately 2 hours in standard practice, sufficient for meaningful organ reconditioning
4. Practical Takeaways for Clinicians
- Adopt NRP for DCD donors where legislation and resources permit; evidence strongly supports reduction in ischemic cholangiopathy and improved multi-organ outcomes
- Understand legislative constraints: premortem cannulation, heparin administration, and inclusion of thoracic organs in NRP circuits vary by jurisdiction and must be factored into institutional protocols
- Standardize functional warm ischemic time (fWIT) definitions across centers to enable meaningful outcome comparisons; current definitions remain heterogeneous internationally
- Evaluate each organ individually: perfusion strategy should be tailored to donor characteristics, organ quality, and transplant goals — not applied uniformly