Article Info

Author Affiliations: Organ Transplant Center, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China (Han M, Guo ZY, Zhao Q, Wang XP, Yuan XP, Jiao XY, Yang CH, Wang DP, Ju WQ, Wu LW, Hu AB, Tai Q, Ma Y, Zhu XF and He XS)

Contributors: HXS proposed the study. HM, GZY and ZQ wrote the first draft. WXP, YXP, JXY and YCH collected and analyzed the data. All authors contributed to the design and interpretation of the study and to further drafts. HM, GZY and ZQ contributed equally to the article. HXS is the guarantor.

METHODS: From July 2011 to August 2012, our center performed 26 liver transplants from a pool of 29 deceased donors. All organ donation and allograft procurement were conducted according to the national protocol. The clinical data of donors and recipients were collected and summarized retrospectively.

RESULTS: Among the 29 donors, 24 were China Category II donors (organ donation after cardiac death), and five were China Category III donors (organ donation after brain death followed by cardiac death). The recipients were mainly the patients with hepatocellular carcinoma. The one-year patient survival rate was 80.8% with a median follow-up of 422 (2-696) days. Among the five mortalities during the follow-up, three died of tumor recurrence. In terms of post-transplant complications, 9 recipients (34.6%) experienced early allograft dysfunction, 1 (3.8%) had non-anastomotic biliary stricture, and 1 (3.8%) was complicated with hepatic arterial thrombosis. None of these complications resulted in patient death. Notably, primary non-function was not observed in any of the grafts.

Organ shortage is a major issue limiting the practice of organ transplantation. In the United States since 2002, the total number of wait-listed candidates gradually increased. However, in the past several years, deceased donor organ donation rates have remained unchanged.^[1] The situation in China is even more challenging. Therefore, surgeons around the world continue to search for ways to expand the donor pool to minimize the organ shortage.

In March 2011, the Chinese Ministry of Health and the Red Cross Society of China jointly initiated a pilot program for deceased organ donation from general citizens.^[2,^3] There are three categories of deceased organ donation in China, including Categories I (organ donation after brain death, DBD), II (organ donation after cardiac death, DCD), and III (organ donation after brain death followed by cardiac death, DBCD). National protocols have been developed for each category of donation. Importantly, the China Organ Transplant Response System (COTRS), a national organ allocation computer program, has been established to allocate organs equitably and transparently.

In response to this program, our center began to use organs from deceased donors to meet the increasing demand for organs. Currently, we host one of the largest deceased organ donation and transplantation programs in China. However, it has been shown that liver transplants from DCD donors have inferior outcomes in comparison with those from DBD donors.^[4] The quality of DBCD donor allografts may be even worse than that of DCD donor allografts because the DBCD organs suffer a primary inflammatory storm injury related to brain death and a subsequent warm ischemia injury related to cardiac death. Moreover, the lack of experience in maintenance and management of potential DBD donors compromises the quality of DBD organs in China. Thus, there are still a number of Chinese transplant professionals concerned about the quality of liver allografts from these deceased donors. In this article, we present our initial experience with the short-term outcomes of liver transplantation using organs from deceased donors in this pilot program.

All cases of organ donation were conducted according to the protocols for China Categories I, II, and III donors.^[3] After informed consent was obtained from the donor's family, removal of life support occurred in the intensive care unit (ICU) or operating room. If a donor's family refused donation before the procurement operation, the donation process was terminated. If the ICU could not satisfy the requirements for the procurement operation, the donor was transferred to the operating room for procurement as long as his or her family had no objection. Before organ procurement, no heparin or phentolamine was used.

After the legal two or five minutes standoff time, the donor immediately underwent a "super-rapid" procurement technique. In brief, this involved a rapid thoraco-abdominal incision, rapid cannulation of the abdominal aorta and superior mesenteric or portal vein for perfusion with the University of Wisconsin (UW) solution and prompt hepatectomy. The intra-abdominal organs were removed en bloc and placed in UW solution at 4 �� for storage. The bile duct was flushed in situ with hypertonic citrate adenine solution and preserved by UW solution ex situ. The organ procurement team only procured the organs that the donor's family consented. All recipient operations were performed using either a modified piggy-back or classic orthotopic liver transplant procedure.

All the organs were allocated by the COTRS based upon the model for end-stage liver disease (MELD) score, medical urgency and the waiting time of patients on the list. The allocation principles have been outlined in the Ministry of Health protocol titled "The basic principle of Chinese human organ distribution and sharing and core policy of liver and kidney transplant".^[5] Briefly, all the patients received a medical urgency score before being added to the waiting list. The MELD score was the major determinant of organ allocation. Patients with non-metastatic hepatocellular carcinoma (HCC) are eligible for priority listing and receive extra MELD points. With these considerations in mind, all HCC candidates should provide alpha-fetoprotein and computed tomography results to the COTRS system. Patients older than 12 years with 1 nodule 2-5 cm in size or 2-3 nodules all <3 cm in size are eligible for a MELD score of 22. All patients must be evaluated for extra-hepatic metastases and must be reevaluated every three months. Additional MELD points equivalent to a 10% mortality may be added every three months in those who continue to meet the criteria for stage 2 disease.

Donor information including age, gender, causes of death, University of Wisconsin Donation After Cardiac Death Evaluation Tool (UWET) score, warm ischemia time (WIT), cold ischemia time (CIT), and sharing status (geographic location) were recorded.^[6] The WIT was defined as the time from withdrawal of both ventilator and cardiac support to the start of cold perfusion of the organ (immediately followed by aortic cross clamping). The CIT was defined as the time from infusion of cold preservation solution until portal reperfusion of the liver in the recipient.

Recipient information including pre-transplant, intraoperative and post-transplant parameters was recorded. Early allograft dysfunction (EAD) was defined as described by Olthoff et al.^[7] The diagnosis of ischemia type biliary lesion (ITBL) was defined as described by Collettini et al.^[8] When endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiography (PTHC), or magnetic resonance cholangiopancreatography (MRCP) showed signs of segmental or diffuse intra- or extra-hepatic strictures, necrosis, abscesses, or destruction of the biliary tree, the diagnosis of ITBL was suspected. Since ERCP and PTHC are invasive procedures, they were only used when necessary, while MRCP was routinely performed when hyperbilirubinemia without a defined reason occurred. The diagnosis was established only after hepatic arterial thrombosis (HAT), ABO incompatibility, biliary anastomotic stricture, or other reasons for biliary destruction (e.g., chronic ductopenic rejection) were ruled out.

All statistical analyses were performed using commercially available software (SPSS v18.0; SPSS Inc., Chicago, IL, USA). Survival rates were estimated using the Kaplan-Meier method. Univariate and multivariate analyses were conducted to identify risk factors for EAD development. A P value <0.05 was considered as statistically significant.

Since the inception of the deceased organ donation program in July 2011, 29 donors were accepted at our hospital. All these donors were citizens from the general population. The donors were individuals with devastating cerebral injury with no hope of recovery or diagnosed as brain dead. All of them were critically ill in the ICU on mechanical ventilation. These donors underwent successful donation with 29 livers procured. One liver was discarded due to poor pre-donation liver function with a total bilirubin (TBIL) of 93.0 µmol/L and apparent liver steatosis found.

The current donor series included 24 males and 5 females, with a median age of 29 (6-56) years and a mean BMI of 20.8±3.3 kg/m². The causes of death were craniocerebral trauma (n=16), cerebral hemorrhage (9), cerebral infarction (1), hypoxic ischemic encephalopathy (1), carbon monoxide poisoning (1), and brain glioma (1). China Category II donors made up 82.8% (24/29) of the donors, and the remaining (17.2%) were China Category III donors. The median ICU stay was 7 (1-23) days. The mean levels of serum creatinine (sCr), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and TBIL were 167.7±154.1 µmol/L, 104.5±130.3 U/L, 130.1±147.3 U/L, and 23.6±20.1 µmol/L, respectively. In order to evaluate each donor for the possibility of DCD, UWET scores were calculated, and the median score was 19 (17-22), indicating the suitability of these donors for DCD. A total of 19 (65.5%) donors received vasopressors while they were in the ICU or operating room. The mean WIT was 17.2±4.4 minutes, whereas the mean CIT was 365.6±115.1 minutes.

Among the 28 donor livers, two were procured in our hospital and allocated to Wuhan and Tianjin and the remaining 26 were transplanted at our transplant center. The median age of the recipients at the time of transplant was 52 (26-71) years. The diagnoses of the 26 liver transplant recipients were as follows: HBV-related HCC (n=18), fulminant liver failure (3), HBV-related liver cirrhosis (2), hilar cholangiocarcinoma (1), Budd-Chiari syndrome (1), and Caroli's disease (1). According to the COTRS rule for MELD score calculation, patients with HCC within the Milan criteria received extra MELD points. The median calculated MELD score was 22 (12-40), the median Child-Pugh score was 8 (5-13), and the median length of hospital stay was 31 (2-80) days. Tables 1 and 2 depict the recipient characteristics and tumor features of the HCC recipients, respectively.

The median follow-up period for all recipients was 422 (2-696) days. By the end of this study, 80.8% (21/26) of the recipients were still alive and had been followed for more than one year. A total of 5 patients died after transplantation. One was a 63-year-old man diagnosed with fulminant liver failure and hepatorenal syndrome with a MELD score of 40. During the operation, the recipient suffered from sudden ventricular fibrillation and was rescued by electrical defibrillation. He died of cardiac arrest on day 2 after transplantation. Another patient suffered from poor liver function after surgery, which gradually progressed to severe liver abscess. He died of liver failure seven months after transplantation. Two patients with HBV-related HCC (T3N0M0, exceeding UCSF criteria) died from tumor recurrence at 3 and 7 months after transplantation, respectively. The remaining patient died from recurrence of hilar cholangiocarcinoma at 8 months after transplantation.

ALT and AST levels reached their peaks on day 1 after transplantation, then decreased sharply during the next five days and declined to normal on day 15 after transplantation. The mean level of serum TBIL peaked on day 1 post-transplantation and progressively improved until stabilizing in the normal range by the end of the first month. Table 3 summarizes the levels of post-transplant serum liver enzymes and TBIL.

Among the 21 survivors, 15 had post-transplant complications, 5 had more than one complication. Six patients had pulmonary infections, 3 patients were complicated with acute rejection (AR), and 9 patients suffered from EAD. The complications of our patients included ITBL (n=1), cholestasis (1), HAT (1), liver abscess (1), alimentary tract hemorrhage (1), abdominal bleeding (1), concurrent pancreatic and intestinal fistula (1), and fat liquefaction of incision (1). Interestingly, although a large necrotic liver mass was noticed in the right lobe of the liver in the patient suffering from HAT at week 3 after transplantation, the liver function was not impaired. After percutaneous transfemoral intra-arterial thrombolysis therapy, the thrombotic artery was re-perfused and the necrotic volume was decreased significantly after six weeks. Primary non-function (PNF) did not occur in our patients.

Univariate analysis were performed to identify risk factors for the development of EAD (Table 4). Donor ICU stay >7 days (P=0.025), donor peak ALT level >100 U/L (P=0.018) and recipient Child-Pugh score <7 (P=0.039) were significant risk factors for the development of EAD. Multivariate analysis indicated that donor ICU stay >7 days, peak ALT >100 U/L and recipient Child-Pugh score <7 were not significantly independent risk factors for the development of EAD (all P>0.05) (Table 5).

The shortage of donors for organ transplantation forced the transplant society to search for any possible source. Organ transplant centers in China have been trying to use organs from living donors or brain death donors.^[9,^10] However, currently there are a number of challenges to the use of these organs in China because of ethical and legislative issues.^[2] Therefore, organ donation from deceased citizens is the best option for the transplant community to expand the donor pool. Importantly, the number of potential deceased donors is large enough to help mitigate the disparity. In about 9.62 million Chinese people who died in 2011,^[11] those who died of cardiovascular diseases, cerebrovascular diseases, and traumatic injuries and poisonings account for 21.30%, 20.22% and 5.47%, respectively. These death people (4.52 million) are potentially available for organ donation.

DCD donors can be classified into five categories according to the Maastricht criteria.^{[12, 13]} In 2011, China developed its own deceased organ donation classification.^{[2, 3]} Both China Categories I and II of organ donation are internationally accepted approaches. However, China Category III organ donation is a unique category in China. In this case, the donor satisfies the DBD criteria, but the relatives do not allow to harvest the liver when the patient still has heart beat, thus the donation is postponed until life support is withdrawn and cardiac function terminated. Technically, China Category III donors are similar to type IV donors of the Maastricht criteria, but the cessation of cardiac function is planned in the former. In this series, 5 donors (17.2%) were classified as China Category III donors, and the remaining were China Category II (Maastricht criteria type III) donors. However, due to the lack of confirmatory diagnostic tools at the local hospitals of some donors during the early phase of organ donation practice, we could not confirm a diagnosis of brain death even if it was suspected in some donors. Moreover, we can only routinely evaluate the brain death under the consent of the family.

The transplant outcomes in the current studies were encouraging. The one-year patient and graft survival rates were 80.8% and 80.8%, respectively. In this study, five recipients died, one because of a cardiovascular accident, one allograft loss and three tumor recurrence. Therefore, we can anticipate that patient survival will be improved in the future because a higher proportion of donated organs will be allocated to candidates with early HCC or chronic cirrhosis. In fact, the reported one-year patient (79.0%-91.5%) and graft survival rates (65.0%-88.1%) in liver transplantation using DCD donors vary greatly accross different centers.^[14,^15] The variability in patient and graft survival might be explained by the differences in DCD volume, the categories of DCD donors (controlled or uncontrolled), maximal WIT and other factors that varied between these studies.

DCD liver transplantation is associated with a higher incidence of allograft dysfunction and biliary complications.^[4] Indeed, as early as 2007 when we started using DCD livers, PNF occurred in two cases and resulted in deaths. These failures were attributable to a lack of experience in donor maintenance and evaluation and resulted in a suspension of our DCD program. In the current series, no PNF was documented, which is much lower than reported in previous studies (3.7%-12.0%).^{[14, 15]} The incidence of EAD was 34.6% (9/26) in this group of patients, which lines between 23.6% in DBD and 68.4% in DCD liver transplantation reported by Croome et al.^[16] The authors of this study further claim that EAD is a valid predictor of patient and graft survival in recipients of DBD grafts but not in those of DCD grafts. We did not find the difference in one-year patient and graft survival between patients with or without EAD in the current series. Moreover, we were unable to identify the independent risk factors associated with the development of EAD due to the small sample size.

Importantly, ITBL is the most troublesome and common complication leading to a secondary liver transplantation. It is believed that the incidence of ITBL is higher in DCD than that in DBD liver recipients.^[17] However, only one patient was complicated with ITBL in this series. A recent retrospective study in over 1750 transplants identified six risk factors for ITBL, but in the multivariate analysis only long CIT and organ recovery without high pressure hepatic artery perfusion remained statistically significant.^[18] Therefore, the short mean CIT may, in part, explain the low incidence of ITBL in this series.

Eighteen (69.2%) of the recipients in this series were diagnosed with HCC, one third of which were within the Milan criteria. There is still no consensus on the selection criteria of HCC patients for liver transplantation in China. Since most patients waiting for liver transplantation are advanced HCC patients, the basic requirements in China for these patients are the absence of main vascular invasion and extra-hepatic metastasis. Zheng et al^[19] established the "Hangzhou criteria" in line with China's basic requirements. This system achieved an estimated 5-year survival rate of 70% after liver transplantation. In the current series, the majority of HCC recipients were within the "Hangzhou criteria". The HCC recipients yielded a comparable one-year patient survival rate with their benign counterparts, and the two HCC recipients died of tumor recurrence were beyond the "Hangzhou criteria", suggesting that the "Hangzhou criteria" are equally important criteria in China as the Milan criteria in Western counties.

The outcomes of the patients in the current series are reasonable, with short-term outcomes similar to previous reports from other centers.^{[14, 15]} First, all of the donors were China Category II (Maastricht category III) or China Category III donors who were in severe condition and died soon after mechanical assistance was withdrawn. The quality of uncontrolled DCD livers is inferior to that of controlled DCD livers and machine perfusion techniques are required to improve the viability of uncontrolled DCD organs.^[20] Therefore, we believe that, in China, uncontrolled DCD organs should not be recommended until the DCD program is improved. Second, most of the mechanically assisted withdrawals occurred in the operating room, and the organ procurement procedures were performed by skilled surgeons, which further shortened the WIT. The mean CIT was also short because all of the allografts were transplanted at a local center, and efforts were made to minimize the CIT. Finally, the donors in the current series were younger than those in Western countries.^[4]

Our initial experience of a deceased donor liver transplant program represents one of the first attempts to use organs from a voluntary organ donation system in China. Although we are facing many challenges, we believe that with careful donor evaluation and maintenance, liver allografts from cardiac death donors can provide an important alternative to liver allografts from living donors and brain death donors. The success of our cardiac death organ donation and transplantation program will encourage other organ transplant centers to set up or expand their own programs, which will help to relieve the increasing donor organ shortage and to establish an equitable organ donation system in China.

7 Olthoff KM, Kulik L, Samstein B, Kaminski M, Abecassis M, Emond J, et al. Validation of a current definition of early allograft dysfunction in liver transplant recipients and analysis of risk factors. Liver Transpl 2010;16:943-949. PMID: 20677285

8 Collettini F, Kroencke TJ, Heidenhain C, de Bucourt M, Renz D, Schott E, et al. Ischemic-type biliary lesions after ortothopic liver transplantation: diagnosis with magnetic resonance cholangiography. Transplant Proc 2011;43:2660-2663. PMID: 21911142

13 Sánchez-Fructuoso AI, Prats D, Torrente J, Pérez-Contín MJ, Fernández C, Alvarez J, et al. Renal transplantation from non-heart beating donors: a promising alternative to enlarge the donor pool. J Am Soc Nephrol 2000;11:350-358. PMID: 10665943

16 Croome KP, Wall W, Quan D, Vangala S, McAlister V, Marotta P, et al. Evaluation of the updated definition of early allograft dysfunction in donation after brain death and donation after cardiac death liver allografts. Hepatobiliary Pancreat Dis Int 2012;11:372-376. PMID: 22893463

17 Verdonk RC, Buis CI, van der Jagt EJ, Gouw AS, Limburg AJ, Slooff MJ, et al. Nonanastomotic biliary strictures after liver transplantation, part 2: Management, outcome, and risk factors for disease progression. Liver Transpl 2007;13:725-732. PMID: 17457935