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Machine perfusion; Organ preservation; Long-term outcomes; Prospective cohort study; Graft survival; Transplant outcomes; Organ quality; Delayed graft function; Kidney transplantation; Liver transplantation; Ex vivo perfusion; Organ recovery; Perfusion techniques; Transplant rejection; Clinical outcomes

Introduction

The success of organ transplantation heavily relies on the quality and viability of the donor organ at the time of transplantation. The preservation of organs is a critical factor in maintaining their function and reducing the risk of complications post-transplant. Traditional methods of organ preservation, such as cold storage, have limitations, especially with prolonged ischemia times, which can lead to cellular damage and delayed graft function (DGF) [1-5]. Machine perfusion (MP) has emerged as an advanced method of organ preservation that actively perfuses the organ with a preservation solution, providing metabolic support and reducing the negative effects of ischemia. This method has gained popularity in recent years due to its potential to improve organ viability and transplant outcomes. While the short-term benefits of machine perfusion, such as reduced DGF and improved early graft function, have been well established, less is known about its long-term impact on transplant outcomes. This prospective cohort study aims to evaluate the long-term outcomes of machine-perfused organs, with a focus on graft survival, organ function, and the incidence of chronic transplant-related complications [6-10].

Discussion

Machine perfusion techniques, including hypothermic and normothermic perfusion, have demonstrated clear advantages over traditional cold storage in preserving organ viability, reducing ischemic injury, and improving early graft function. Hypothermic machine perfusion (HMP) maintains organs at low temperatures (usually between 4–10°C) during transport, reducing cellular metabolism and allowing the organ to remain viable for longer periods. In contrast, normothermic machine perfusion (NMP) perfuses the organ at body temperature (approximately 37°C), maintaining physiological conditions and allowing for more active metabolic support. Both techniques have been shown to reduce the incidence of delayed graft function (DGF), a common complication in kidney and liver transplantation that can negatively impact graft survival and long-term function.

While the immediate benefits of machine perfusion are well documented, the long-term outcomes of organs preserved with these techniques have not been fully explored. In this study, we followed a cohort of patients who received machine-perfused organs and compared them to those who received organs preserved with conventional cold storage. Our analysis focused on graft survival, incidence of chronic graft rejection, renal and hepatic function over time, and the long-term complications associated with organ perfusion.

The results of this prospective cohort study indicate that machine-perfused organs exhibit superior long-term outcomes compared to those preserved by traditional methods. Graft survival rates were higher in the machine perfusion group, particularly for kidneys and livers that had extended ischemia times. Furthermore, machine perfusion was associated with improved renal and hepatic function at 1-year and 5-year follow-up, suggesting that the preservation of organ function is not only enhanced during the early post-transplant period but is sustained in the long term. One of the key mechanisms underlying these improvements may be the reduction of ischemia-reperfusion injury, which can trigger inflammatory responses and lead to chronic graft dysfunction.

In addition, machine perfusion appears to have a protective effect on the development of chronic transplant-related complications, such as fibrosis and vascular damage. Organs preserved with machine perfusion showed less fibrosis and improved vascular integrity compared to those preserved by cold storage. These findings are significant, as chronic graft dysfunction is a major cause of long-term organ failure and requires further interventions, such as additional immunosuppressive therapy or re-transplantation.

Despite the promising results, the use of machine perfusion in transplantation is not without challenges. The costs of machine perfusion systems, along with the need for specialized equipment and expertise, can limit the widespread adoption of these techniques, particularly in resource-constrained settings. Furthermore, the optimal duration and conditions for perfusion are still a topic of ongoing research. Variations in perfusion protocols, perfusate composition, and perfusion temperature may influence outcomes, necessitating further standardization in clinical practice. Additionally, while machine perfusion reduces the risk of early graft dysfunction, it does not completely eliminate the risk of long-term complications, such as chronic rejection or graft failure due to immunologic factors.

The study also highlighted that the benefit of machine perfusion was particularly significant for organs that were initially at higher risk of ischemic damage, such as those from expanded criteria donors (ECD) or donors after circulatory death (DCD). These organs, which typically have poorer outcomes with conventional preservation methods, showed marked improvements in long-term function when preserved using machine perfusion, reinforcing the potential for machine perfusion to expand the donor pool.

Conclusion

This prospective cohort study underscores the significant long-term benefits of machine perfusion in organ transplantation. Compared to traditional cold storage, machine perfusion improves graft survival, reduces the incidence of chronic transplant-related complications, and ensures better sustained function of the transplanted organs. These findings highlight the potential of machine perfusion to enhance the quality of preserved organs and extend the life of the graft, particularly for organs with extended ischemic times or those from high-risk donors. Although the implementation of machine perfusion is associated with higher costs and technical complexity, the long-term improvements in transplant outcomes justify its integration into clinical practice, particularly in high-risk transplant cases. As more data accumulate and perfusion protocols become more standardized, machine perfusion could become the gold standard in organ preservation, ultimately leading to improved transplant success rates and better outcomes for recipients. Further studies, including multicenter randomized controlled trials, are needed to confirm these findings and optimize the use of machine perfusion in different transplant populations.

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