Liver transplant (LT) is the only effective treatment for patients with end-stage liver disease. However, there are many difficulties in its clinical application. On the one hand, there are many patients in the world who cannot receive transplants due to a shortage of donor organs. For example, the growing demand for liver grafts remains an unsolved challenge for the transplant community (1). According to the report of the Organ Procurement and Transplantation Network (OPTN), the number of new liver transplantation waiting list registrations in the United States (12,767 cases) continued to grow in 2019 (2). Donor organ shortage is common in various countries to varying degrees, including the persistent shortage of deceased donor organs for transplantation and the limited number of potential donors after brain death (3). On the other hand, ischemia during an organ transplant is a temporary interruption of blood flow to the organ during the transplant. This can occur during the organ’s removal from the donor and transport to the recipient (known as cold ischemia), and during the surgical implantation process (known as warm ischemia). Ischemia can lead to tissue damage and inflammation, leading to poor transplant outcomes. In liver transplantation, prolonged cold ischemia is associated with an increased risk of graft dysfunction and primary non-function, while warm ischemia during implantation can lead to delayed graft function and reduced graft survival.

Previous studies suggested that longer cold/warm ischemia time was identified as an independent risk factor for moderate to severe ischemia–reperfusion injury (4). Longer cold ischemia is associated with poorer liver transplantation outcomes (5). A similar situation has been reported in kidney transplantation. For example, the current gold standard for preserving donor kidneys is static refrigeration at 4°C. However, this can lead to renal ischemia–reperfusion injury, which adversely affects graft survival and function (6, 7). In fact, risk factors associated with primary graft nonfunction include donor age, cold ischemia time, warm ischemia time, and graft quality. A study based on data from the United Kingdom Transplant Registry suggests that cold ischemia duration of more than 8 h is a risk factor for primary non-function and reduced graft survival after liver transplantation (8). Moreover, currently available donor organs are more likely to come from marginal donors (such as those from older, obese individuals), and these marginal organs tend to have a higher risk of ischemia–reperfusion injury. Therefore, how to limit or even reverse graft ischemia is of great significance for improving the success rate of transplantation (9).

Hypothermic preservation is the storage of organs or tissues in a relatively low temperature environment (2 ~ 8°C), often used to preserve the liver, kidney, heart, etc. Currently, the majority of deceased donor livers are preserved via the cold static preservation technique in transport containers with melting ice as the medium for maintaining that temperature. Donor livers usually need to be stored in cold storage for a long period of time during transport from donor to recipient hospital prior to transplantation. Cold ischemia time was defined as the time interval between liver acquisition and liver reperfusion. In the clinical practice of organ transplantation, the cold/warm ischemia process of donor organ after circulatory death may affect the viability of donor organ.

Currently, many measures are used to reduce ischemic damage to candidate organs in order to optimize donor organ quality. For example, normothermic regional perfusion and ex situ perfusion techniques can enhance the preservation, evaluation, resuscitation, and/or repair of damaged organs, thereby improving overall organ quality (3). Use of hypothermic machine perfusion immediately before liver transplantation reduces the chance of perfusion dysfunction during early transplantation. Hypothermic machine perfusion can also reduce the risk of delayed graft function and improve graft survival (10).

In July 2017, the first affiliated hospital of Sun Yat-sen university successfully carried out the first ischemia-free liver transplantation (IFLT) in the world. As ischemia-free organ transplant technology has significantly improved the performance of medical services in the field of liver transplant, a professional team from the organ transplantation department of this hospital was awarded the Grand Prize in the 2020 international quality innovation competition. At present, ischemia-free transplant is considered as a milestone in the history of organ transplant, which could be extended to the transplantation fields of heart, lung and kidney, and has a broad application prospect.

Scientific evaluation of medical service performance is helpful to improve the clinical practice of organ transplant. Diagnosis-related groups (DRGs) are cases combination tools developed by American scholars in the 1970s, which are suitable for the evaluation of short-term hospitalization medical service performance and medical insurance payment (11, 12). Now DRGs were widely used in many countries and regions in North America, Europe, Oceania and Asia (13–15). Previous studies have used DRGs tool to evaluate the service performance and hospitalization cost of care for cancers (16, 17), spinal surgery (18, 19) and carotid stent implantation (20). However, to our knowledge, there have been no studies using the DRGs tool to evaluate the performance of medical care for organ transplant. Therefore, this study aimed to evaluate and compare the overall medical service performance of the organ transplant department between the pre-IFLT and post-IFLT periods.

Ischemia-free transplantation technology can effectively improve the clinical outcome of organ transplant (26). In order to assess the impact of this innovative technology on the medical service performance, we used the DRGs tool to evaluate the medical service performance in the organ transplant department of Sun Yat-sen university’s first hospital from 2016 to 2019. The results showed that after the IFLT implementation, the medical service performance indicators of organ transplant department showed an improvement trend, suggesting that the IFLT implementation of improved the medical service capacity of the department.

Normal machine perfusion (NMP) is a method of organ preservation that protects donor organs between acquisition and transplantation (27), contributes to organ utilization and improves post-transplant outcomes (28, 29). Previous studies have shown that the application of NMP can prevent the occurrence of IRI by inhibiting inflammation and promoting graft regeneration (30). However, as we know, the combination of NRP and HMP is often used for machine perfusion in the clinical practice of organ transplant (31). In this case, IRI may still occur in donor organs. Therefore, the hospital where this study was conducted successfully carried out the first IFLT in the world. IFLT enables the donor organ to obtain blood supply and support throughout the whole process, avoiding the IRI of the donor organ and reducing the risk of delayed graft function recover and acute rejection after surgery, thus further improving the transplant effect (32). The clinical practice shows that this innovative technology plays a positive role in promoting the medical service performance of the organ transplant department.

The payment method based on the DRGs case mix is a promising way for medical charging services (33, 34). It is reported that DRGs can help shorten hospital stay (35), reduce operations requiring expensive surgical instruments (36), and reduce medical costs (37). Although a lot of basic work needs to be carried out to realize DRG, including establishing adequate infrastructure, improving human resource capacity and improving the information management system (38, 39), these works are of great value, because scientific evaluation of medical service performance helps to improve clinical practice. At present, the DRGs tool has been widely concerned and applied to several clinical professional medical service evaluation (40). As far as we know, there is no research on the medical performance evaluation of organ transplant specialty using DRGs. Our research showed that DRG was an effective tool to evaluate the medical service performance of organ transplant specialty.

In this study, we used the CN-DRGs tool to analyze the medical service performance of organ transplant cases in the hospital. The results showed that the medical service performance in the organ transplant department showed an upward trend after the IFLT implementation. Specifically, in terms of medical income, the income structure of organ transplant department was more optimized. In terms of medical service capacity, both the number of DRGs and CMI showed an upward trend. The proportion of cases with higher RW (such as RW 5–10) increased, indicating that the type, scope and average technical difficulty of cases treated by organ transplantation department improved. It is worth mentioning that the proportion of organ transplant cases increased significantly during the post-IFLT period, indicating that the performance of professional medical service in this department improved. In terms of service efficiency, there was no statistical difference of TEIs between pre- and post-IFLT implementation, suggesting that the organ transplant department should pay more attention to the LOS in the future clinical practice. Meanwhile, the difference of CEIs pre- and post-IFLT was statistically significant, indicating that the cost of treating the same disease in organ transplantation department was significantly reduced. In terms of service safety, the mortality rate of low-risk cases in the organ transplant department was 0 throughout the study period, reflecting that the service safety of the department was good. Therefore, the indicators of DRGs, including TW, DRGs, CMI, TEI and CEI, have improved to varying degrees after the application of IFLT, suggesting that IFLT can help improve the medical service performance of the organ transplantation department. It is worth mentioning that, as shown in Figure 4C, compared with the CEI in 2016, the CEI in 2019 was significantly reduced, suggesting significant optimization in terms of hospitalization cost indicators. This may be related to the fact that IFLT recipients recover better after surgery, resulting in lower costs. The above results suggest that the application of IFLT can improve the medical service performance of organ transplantation department. Meanwhile, DRGs tools can accurately assess medical service performance.

Moreover, compared with CLT cases, the average postoperative LOS decreased significantly, suggesting that IFLT can effectively improve the postoperative recovery of patients. Previous studies suggest that there is a difference in the LOS after LT between China and the United States. According to data released by the Scientific Registry of Transplant Recipients (SRTR, https://www.srtr.org/) on January 5, 2023, the median postoperative LOS after LT in the United States was 10 days. Meanwhile, the postoperative LOS after LT varies by medical institution in the United States. For example, the median postoperative LOS after LT at Mayo Clinic Hospital Arizona was 6 days, while median postoperative LOS after LT at UF Health Shands Hospital was 14 days. Compared with that in the United States, the median postoperative LOS after LT in China was relatively longer. For example, a retrospective study from Beijing suggested that the median postoperative LOS after LT was 16 days (41). In addition, a retrospective study from Shanghai suggested that the median postoperative LOS after pediatric living donor LT was 24 days (42). In the present study, the mean postoperative LOS after LT in the post-IFLT period was 26.73 days, which was similar to the data reported by other medical institutions in China.

We believe that the reasons why LT patients in China have longer postoperative LOS compared to that in the United States may include the following: Firstly, there are differences in the medical systems of the two countries. Medical institutions in China have different practices in terms of care and management after LT, which may require a longer hospital stay. Secondly, there are differences in the characteristics of patients. Chinese patients may have different risk factors, which may require more intensive in-hospital monitoring, thus extending the LOS. Thirdly, there is a difference in cultural and social factors. Chinese families are likely to become more involved in caring for their family members during hospital stays, which could extend the LOS. Finally, differences in alternative therapy or medication use may also affect LOS.

There were several potential limitations in this study. Firstly, medical service performance evaluation based on DRGs requires high-precision FPMR. FPMR data used in this work was provided by the medical record management department of the hospital studied. Although the disease and surgery coding in FPMR had been under standard quality control, there is still the possibility of inaccurate coding, which may affect the accuracy of the evaluation results. Secondly, there was a lack of localized DRGs suitable for Guangdong Province, which may affect the accuracy of medical service performance evaluation data.

In conclusion, this study showed that medical performance indicators including total weight, CMI, CEI, and TEI of patients admitted to the organ transplant department in the post-IFLT period were improved to varying degrees compared with those in the pre-IFLT period, suggesting that the application of IFLT technology could contribute to improving the medical service performance of the organ transplant department. Meanwhile, the DRGs tool may help transplant departments to coordinate the future delivery planning of medical service.

The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding authors.

WZ and WC designed the study and revised the manuscript. JL, ZL, and YX collected and analyzed the data. JL interpreted the data and drafted the manuscript. HP, YZ, ZX, YL, and ZS revised the manuscript. All authors contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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