Current achievements and future applications of ex vivo lung perfusion; where do we go from here?

Centralized Static Ex Vivo Lung Perfusion in the United States

BACKGROUND

Ex vivo lung perfusion (EVLP) may improve donor lung utilization but requires significant infrastructure and expertise. Centralized EVLP facilities may mitigate these requirements.

METHODS

From the United Network for Organ Sharing database, we identified 345 adults undergoing isolated, first-time lung transplantation using donor lungs perfused by static EVLP (March 1, 2018-December 31, 2022). Recipients of lungs perfused at centralized EVLP facilities (n = 165) were compared with recipients of lungs perfused at individual transplant centers (n = 180). Propensity score matching was used to create balanced groups for comparison.

RESULTS

Centralized EVLP facilities were increasingly used from 2018 to 2022 (35.3% vs 55.8%, P = .04) and were more likely used when the annual center volume of EVLP lung transplants was low. Compared with allografts placed on EVLP at individual transplant centers, those placed on EVLP at centralized facilities had longer median ischemic time (11.3 vs 9.6 hours, P < .001) and were less likely to come from donation after circulatory death donors (25.4% vs 39.5%, P = .003) or be used for double-lung transplant (73.3% vs 83.9%, P = .02). In 102 well-matched recipient pairs, 2-year survival was equivalent between those receiving allografts perfused at centralized facilities (77.9%; 95% CI, 68.0%-85.1%) vs individual transplant centers (77.7%; 95% CI, 67.8%-84.9%; P = .90). Multivariable Cox regression analysis also showed equivalent 2-year survival (adjusted hazard ratio, 1.02; 95% CI, 0.57-1.84; P = .95).

CONCLUSIONS

Transplanting lung allografts that underwent static EVLP at centralized facilities had similar outcomes compared with transplanting lungs perfused at individual transplant centers. The centralized model of clinical EVLP can potentially improve access to EVLP.

How do we expand the lung donor pool?

PURPOSE OF REVIEW

Lung transplantation activity continues to be limited by the availability of timely quality donor lungs. It is apparent though that progress has been made. The steady evolution of clinical practice, combined with painstaking scientific discovery and innovation are described.

RECENT FINDINGS

There have been successful studies reporting innovations in the wider use and broader consideration of donation after circulatory death donor lungs, including an increasing number of transplants from each of the controlled, uncontrolled and medically assisted dying donor descriptive categories. Donors beyond age 70 years are providing better than expected long-term outcomes. Hepatitis C PCR positive donor lungs can be safely used if treated postoperatively with appropriate antivirals. Donor lung perfusion at a constant 10 degrees appears capable of significantly improving donor logistics and ex-vivo lung perfusion offers the potential of an ever-increasing number of novel donor management roles. Bioartificial and xenografts remain distant possibilities only at present.

SUMMARY

Donor lungs have proved to be surprisingly robust and combined with clinical, scientific and engineering innovations, the realizable lung donor pool is proving to be larger than previously thought.

Advances in lung transplantation: 60 years on

Lung transplantation is a well-established treatment for advanced lung disease, improving survival and quality of life. Over the last 60 years all aspects of lung transplantation have evolved significantly and exponential growth in transplant volume. This has been particularly evident over the last decade with a substantial increase in lung transplant numbers as a result of innovations in donor utilization procurement, including the use donation after circulatory death and ex-vivo lung perfusion organs. Donor lungs have proved to be surprisingly robust, and therefore the donor pool is actually larger than previously thought. Parallel to this, lung transplant outcomes have continued to improve with improved acute management as well as microbiological and immunological insights and innovations. The management of lung transplant recipients continues to be complex and heavily dependent on a tertiary care multidisciplinary paradigm. Whilst long term outcomes continue to be limited by chronic lung allograft dysfunction improvements in diagnostics, mechanistic understanding and evolutions in treatment paradigms have all contributed to a median survival that in some centres approaches 10 years. As ongoing studies build on developing novel approaches to diagnosis and treatment of transplant complications and improvements in donor utilization more individuals will have the opportunity to benefit from lung transplantation. As has always been the case, early referral for transplant consideration is important to achieve best results.