Evaluation of potential liver donors: limits imposed by donor variables in liver transplantation

The impact of macro- and micro-steatosis on the outcomes of patients who undergo liver transplant: Analysis of the UNOS-STAR database

BACKGROUND AND AIMS

The presence of steatosis in a donor liver and its relation to post-transplantation outcomes are not well defined. This study evaluates the effect of the presence and severity of micro- and macro-steatosis of a donor graft on post-transplantation outcomes.

METHODS

The UNOS-STAR registry (2005-2019) was used to select patients who received a liver transplant graft with hepatic steatosis. The study cohort was stratified by the presence of macro- or micro-vesicular steatosis, and further stratified by histologic grade of steatosis. The primary endpoints of all-cause mortality and graft failure were compared using sequential Cox regression analysis. Analysis of specific causes of mortality was further performed.

RESULTS

There were 9184 with no macro-steatosis (control), 150 with grade 3 macro-steatosis, 822 with grade 2 macro-steatosis and 12 585 with grade 1 macro-steatosis. There were 10 320 without micro-steatosis (control), 478 with grade 3 micro-steatosis, 1539 with grade 2 micro-steatosis and 10 404 with grade 1 micro-steatosis. There was no significant difference in all-cause mortality or graft failure among recipients who received a donor organ with any evidence of macro- or micro-steatosis, compared to those receiving non-steatotic grafts. There was increased mortality due to cardiac arrest among recipients of a grade 2 macro-steatosis donor organ.

CONCLUSION

This study shows no significant difference in all-cause mortality or graft failure among recipients who received a donor liver with any degree of micro- or macro-steatosis. Further analysis identified increased mortality due to specific aetiologies among recipients receiving donor organs with varying grades of macro- and micro-steatosis.

Impact of length of donor ICU stay on outcome of patients after pediatric liver transplantation with whole and ex situ split liver grafts

BACKGROUND

Patients who have a prolonged stay in the intensive care unit (ICU) are often excluded for organ donation because of supposed deleterious effects of a lengthy ICU stay. We aimed to determine the effects of a prolonged donor stay in the ICU on the outcome of liver transplantation (LT) in children.

METHODS

Retrospective review of 89 pediatric LT patients, age 0-18 years, period 2003-2018, including patients having undergone whole organ or in situ split LT. The patients were divided into two groups according to the donor length of stay in the ICU. A prolonged stay was defined as >5 days. Recipient, graft, and donor characteristics were compared; outcome parameters included recipient and graft survival rates and postoperative complications.

RESULTS

Group short (donor ICU stay <5 days) included 75 patients, group long (donor ICU stay >5 days) 14 patients. Baseline characteristics between recipients did not differ. Donors in group long had significantly more infectious complications and a higher gamma glutamyl transferase (gGT) the day of organ recovery. Incidence of biliary complications post-LT was significantly higher in group long (p = .029). Patient and graft survival rates did not differ significantly between groups.

CONCLUSIONS

Donors with a prolonged stay in the ICU should still be considered for liver donation if they fulfill most other selection criteria. Recipients from donors having stayed in ICU >5 days may be at increased risk of biliary complications.

Impact of Pretransplantation CT on Liver Donation in Potential Deceased Organ Donors

BACKGROUND

Computed tomography (CT) is routinely used to determine the suitability of potential living donor liver transplants, providing important information about liver size, vascular anatomy, and the presence of other diseases that would preclude it from safe donation. CT is not routinely used, however, when evaluating eligible deceased organ donors after brain death, a group which comprises most orthotopic liver transplants. After the installation of a CT scanner at a local procurement facility, CTs have been performed on potential deceased organ donors and used, in conjunction with other evaluative protocols, to help direct donation decisions and assist in procurement procedures.

STUDY DESIGN

A retrospective analysis of data from 373 cases spanning 5 years was systematically collected and analyzed, including information pertaining to patient's medical histories, biopsy results, operative findings, and CT results.

RESULTS

CT findings directly impacted the directive decision-making process in 29% of cases in this patient cohort, likely an underestimate, and reliably evaluated important factors including variant vascular anatomy and the presence and severity of hepatic steatosis and cirrhosis.

CONCLUSION

Overall, this study suggests that CT has the potential to play a significant role in procurement procedures and the directive decision-making process, thereby improving the efficiency and accuracy by which potential deceased organ donors are evaluated.

In-hospital mortality of liver transplantation and risk factors: a single-center experience

Background

Liver transplantation (LT) is a life-saving treatment for patients with end-stage liver disease and acute liver failure. However, in-hospital death cannot be avoided. We designed this study to analyze patients' in-hospital mortality rate after LT and the factors correlated with in-hospital death.

Methods

The data of patients who received LT in our hospital between January 11, 2015, and November 19, 2019, were obtained from the China Liver Transplant Registry and medical records. The in-hospital mortality rate was calculated, and factors related to mortality, cause of death, and factors related to cause of death were analyzed by reviewing patients' data.

Results

A total of 529 patients who underwent cadaveric LT were enrolled in this study. Modified piggyback orthotopic LT was performed for all patients. Seventy patients died in the hospital after LT, and the in-hospital mortality rate was 13.2%. Factors including model for end-stage liver disease (MELD) score, Child-Pugh grading, intraoperative blood loss, and anhepatic phase were correlated with in-hospital death. MELD score and intraoperative blood loss were determined as the two independent risk factors of in-hospital death. The first two causes of death were infection (34.3%) and primary non-function (15.7%). Pulmonary fungal infection was the main cause of infectious death. MELD score was the independent risk factor for infectious death, and both body mass index of donors and cold ischemic time were independent risk factors of primary non-function.

Conclusions

In-hospital death poses a threat to certain patients undergoing LT. Our study suggests that the main cause of in-hospital death is an infection, followed by primary non-function.

Steatotic Livers Are More Susceptible to Ischemia Reperfusion Damage after Transplantation and Show Increased γδ T Cell Infiltration

Liver transplantation (LTx) is often the only possible therapy for many end-stage liver diseases, but successful long-term transplant outcomes are limited by multiple factors, including ischemia reperfusion injury (IRI). This situation is aggravated by a shortage of transplantable organs, thus encouraging the use of inferior quality organs. Here, we have investigated early hepatic IRI in a retrospective, exploratory, monocentric case-control study considering organ marginality. We analyzed standard LTx biopsies from 46 patients taken at the end of cold organ preparation and two hours after reperfusion, and we showed that early IRI was present after two hours in 63% of cases. Looking at our data in general, in accordance with Eurotransplant criteria, a marginal transplant was allocated at our institution in about 54% of cases. We found that patients with a marginal-organ LTx showing evidence of IRI had a significantly worse one-year survival rate (51% vs. 75%). As we saw in our study cohort, the marginality of these livers was almost entirely due to steatosis. In contrast, survival rates in patients receiving a non-marginal transplant were not influenced by the presence or absence of IRI. Poorer outcomes in marginal organs prompted us to examine pre- and post-reperfusion biopsies, and it was revealed that transplants with IRI demonstrated significantly greater T cell infiltration. Molecular analyses showed that higher mRNA expression levels of CXCL-1, CD3 and TCRγ locus genes were found in IRI livers. We therefore conclude that the marginality of an organ, namely steatosis, exacerbates early IRI by enhancing effector immune cell infiltration. Preemptive strategies targeting immune pathways could increase the safety of using marginal organs for LTx.

The Coagulation Profile of End-Stage Liver Disease and Considerations for Intraoperative Management

The coagulopathy of end-stage liver disease results from a complex derangement in both anticoagulant and procoagulant processes. With even minor insults, cirrhotic patients experience either inappropriate bleeding or clotting, or even both simultaneously. The various phases of liver transplantation along with fluid and blood product administration may contribute to additional disturbances in coagulation. Thus, anesthetic management of patients undergoing liver transplantation to improve hemostasis and avoid inappropriate thrombosis in the perioperative environment can be challenging. To add to this challenge, traditional laboratory tests of coagulation are difficult to interpret in patients with end-stage liver disease. Viscoelastic coagulation tests such as thromboelastography (Haemonetics Corporation, Braintree, MA) and rotational thromboelastometry (TEM International, Munich, Germany) have helped to reduce transfusion of allogeneic blood products, especially fresh frozen plasma, but have also lead to the increased use of fibrinogen-containing products. In general, advancements in surgical techniques and anesthetic management have led to significant reduction in blood transfusion requirements during liver transplantation. Targeted transfusion protocols and pharmacologic prevention of fibrinolysis may further aid in the management of the complex coagulopathy of end-stage liver disease.

Donor Hepatic Steatosis and Outcome After Liver Transplantation: a Systematic Review

BACKGROUND

There is increasing need to expand availability of donor liver grafts, including steatotic livers. Steatotic liver is associated with poor outcome post-transplantation but with conflicting results in the literature. The aim of this systematic review was to evaluate the impact of steatotic livers on liver transplantation outcomes.

METHODS

An electronic search of OVID Medline and Embase databases was performed to identify clinical studies that reported outcomes of steatotic livers in liver transplantation. Data were extracted, and basic descriptive statistics were used to summarise data pooled from individual clinical studies.

RESULTS

Ninety-two articles were identified, of which 34 met the inclusion criteria, and stratified analysis were performed. There was a lack of standardised definition of primary non-function or impaired primary function amongst the studies and description of type of steatosis. Severely (>60%) steatotic grafts are associated with increased risk of poor graft function, whilst moderate-severe (>30%) steatotic grafts are associated with decreased graft survival.

CONCLUSIONS

Available evidence showed increased risk of poor graft outcome in moderate-severe steatotic livers. A large prospective multi-centred trial will be required to identify the true risks of steatotic livers. Consistent definition of primary non-function/impaired primary function and description of type of steatosis is also required.

Using old liver grafts for liver transplantation: Where are the limits?

The scarcity of ideal liver grafts for orthotopic liver transplantation (OLT) has led transplant teams to investigate other sources of grafts in order to augment the donor liver pool. One way to get more liver grafts is to use marginal donors, a not well-defined group which includes mainly donors > 60 years, donors with hypernatremia or macrosteatosis > 30%, donors with hepatitis C virus or hepatitis B virus positive serologies, cold ischemia time > 12 h, non-heart-beating donors, and grafts from split-livers or living-related donations. Perhaps the most practical and frequent measure to increase the liver pool, and thus to reduce waiting list mortality, is to use older livers. In the past years the results of OLT with old livers have improved, mainly due to better selection and maintenance of donors, improvements in surgical techniques in donors and recipients, and intra- and post-OLT management. At the present time, sexagenarian livers are generally accepted, but there still exists some controversy regarding the use of septuagenarian and octogenarian liver grafts. The aim of this paper is to briefly review the aging process of the liver and reported experiences using old livers for OLT. Fundamentally, the series of septuagenarian and octogenarian livers will be addressed to see if there is a limit to using these aged grafts.

Scoring systems predict the prognosis of acute-on-chronic hepatitis B liver failure: an evidence-based review

Acute-on-chronic hepatitis B liver failure is a devastating condition that is associated with mortality rates of over 50% and is consequent to acute exacerbation of chronic hepatitis B in patients with previously diagnosed or undiagnosed chronic liver disease. Liver transplantation is the definitive treatment to lower mortality rate, but there is a great imbalance between donation and potential recipients. An early and accurate prognostic system based on the integration of laboratory indicators, clinical events and some mathematic logistic equations is needed to optimize treatment for patients. As parts of the scoring systems, the MELD was the most common and the donor-MELD was the most innovative for patients on the waiting list for liver transplantation. This review aims to highlight the various features and prognostic capabilities of these scoring systems.

Deceased donor hyperglycemia and liver graft dysfunction

CONTEXT

Hyperglycemia is common in deceased donors, and provokes numerous adverse events in hepatocytic mitochondria.

OBJECTIVE

To determine whether hyperglycemia in deceased donors is associated with graft dysfunction after orthotopic liver transplant.

METHODS

Charts on 572 liver transplants performed at the Cleveland Clinic between January 2005 and October 2010 were reviewed. The primary measure was time-weighted averages of donors' glucose measurements. Liver graft dysfunction was defined as (1) primary nonfunction as indicated by death or retransplant or (2) liver graft dysfunction as indicated by an aspartate amino transferase level greater than 2000 U/L or prothrombin time greater than 16 seconds during the first postoperative week. The relationship of interest was estimated by using a multivariable logistic regression.

RESULTS

The incidence of graft dysfunction was 25%. No significant relationship was found between the range of donor glucose measurements and liver graft dysfunction after donor characteristics were adjusted for (P= .14, Wald test, adjusted odds ratio [95% CI] for liver graft dysfunction corresponding to a relative doubling in time-weighted average for donor glucose of 1.43 [0.89-2.30]). The results thus do not suggest that strict glucose control in donors is likely to improve graft quality.

Primary graft dysfunction after liver transplantation

BACKGROUND

Primary graft dysfunction (PGD) causes complications in liver transplantation, which result in poor prognosis. Recipients who develop PGD usually experience a longer intensive care unit and hospital stay and have higher mortality and graft loss rates compared with those without graft dysfunction. However, because of the lack of universally accepted definition, early diagnosis of graft dysfunction is difficult. Additionally, numerous factors affect the allograft function after transplantation, making the prediction of PGD more difficult. The present review was to analyze the literature available on PGD and to propose a definition.

DATA SOURCE

A search of PubMed (up to the end of 2012) for English-language articles relevant to PGD was performed to clarify the characteristics, risk factors, and possible treatments or interventions for PGD.

RESULTS

There is no pathological diagnostic standard; many documented definitions of PGD are different. Many factors, such as donor status, procurement and transplant process and recipient illness may affect the function of graft, and ischemia-reperfusion injury is considered the direct cause. Potential managements which are helpful to improve graft function were investigated. Some of them are promising.

CONCLUSIONS

Our analyses suggested that the definition of PGD should include one or more of the following variables: (1) bilirubin ≥ 10 mg/dL on postoperative day 7; (2) international normalized ratio ≥ 1.6 on postoperative day 7; and (3) alanine aminotransferase or aspartate aminotransferase >2000 IU/L within 7 postoperative days. Reducing risk factors may decrease the incidence of PGD. A majority of the recipients could recover from PGD; however, when the graft progresses into primary non-function, the patients need to be treated with re-transplantation.

Septuagenarian and octogenarian donors provide excellent liver grafts for transplantation

BACKGROUND

Wider utilization of liver grafts from donors ≥ 70 years old could substantially expand the organ pool, but their use remains limited by fear of poorer outcomes. We examined the results at our center of liver transplantation (OLT) using livers from donors ≥ 70 years old.

METHODS

From February 2003 to August 2010, we performed 450 OLT including 58 (13%) using donors ≥ 70 whose outcomes were compared with those using donors <70 years old.

RESULTS

Cerebrovascular causes of death predominated among donors ≥ 70 (85% vs 47% in donors <70; P < .001). In contrast, traumatic causes of death predominated among donors <70 (36% vs 14% in donors ≥ 70; P = .002). Unlike grafts from donors <70 years old, grafts from older individuals had no additional risk factors (steatosis, high sodium, or hemodynamic instability). Both groups were comparable for cold and warm ischemia times. No difference was noted in posttransplant peak transaminases, incidence of primary nonfunction, hepatic artery thrombosis, biliary strictures, or retransplantation rates between groups. The 1- and 5-year patient survivals were 88% and 82% in recipients of livers <70 versus 90% and 84% in those from ≥ 70 years old (P = .705). Recipients of older grafts, who were 6 years older than recipients of younger grafts (P < .001), tended to have a lower laboratory Model for End-Stage Liver Disease score (P = .074).

CONCLUSIONS

Short and mid-term survival following OLT using donors ≥ 70 yo can be excellent provided that there is adequate donor and recipient selection. Septuagenarians and octogenarians with cerebrovascular ischemic and bleeding accidents represent a large pool of potential donors whose wider use could substantially reduce mortality on the OLT waiting list.

The incidence of potential missed organ donors in intensive care units and emergency rooms: a retrospective cohort

PURPOSE

There is a shortage of organ donors in Canada. The number of potential organ donors that are not referred to organ procurement organizations in Canada is unknown.

METHODS

We conducted a retrospective cohort study of all deaths in ICUs and emergency rooms not referred to the Human Organ Procurement and Exchange Program in four hospitals between 1 January 2008 and 31 December 2010. The primary outcome was the number of normal and expanded criteria heart-beating donors and circulatory death (DCD) donors.

RESULTS

Of 2,931 deaths, 64 patients were identified as having a high probability for progression to heart-beating donation (Glasgow Coma Score of 3 and three or more absent brainstem reflexes) and 130 patients were assessed for possible DCD donation. The number of potential abdominal and lung heart-beating donors ranged from 3.2 to 7.5 and 0.5 to 2.7 per million population. The number of potential DCD abdominal and lung donors ranged from 3.9 to 6.5 and 2.7 to 4.3 per million population. Potential heart-beating abdominal (p = 0.04) and lung (p = 0.06) donors increased after legislation mandating donation discussion. Non-pupillary brainstem reflexes were documented in fewer than 60 % of records. Life-sustaining treatment was withdrawn in 19 of 46 (41.3 %) cardiac arrest patients not requiring high doses of vasoactive drugs within 24 h.

CONCLUSION

The number of heart-beating or DCD organ donors represented by missed referrals may represent up to 7.5 donors per million population. Improved documentation of brainstem reflexes and encouraging referral of patients suffering cardiac arrest to ICU specialists may improve donor numbers.

The outcomes of patients with severe hyperbilirubinemia following living donor liver transplantation

BACKGROUND

Prolonged hyperbilirubinemia (HB) following living donor liver transplantation (LDLT) can be a risk factor for early graft loss and mortality. However, some recipients who present with postoperative hyperbilirubinemia do recover and maintain a good liver function.

AIM

The purpose of this study was to investigate the risk factors for hyperbilirubinemia following LDLT and to identify predictors of the outcomes in patients with post-transplant hyperbilirubinemia.

METHODS

A total of 107 consecutive adults who underwent LDLT in Nagasaki University Hospital were investigated retrospectively. The patients were divided into two groups according to postoperative peak serum bilirubin level (HB group: ≥ 30 mg/dl; non-HB group: <30 mg/dl). These two groups of patients and the prognosis of patients in the HB group were analyzed using several parameters.

RESULTS

Seventeen patients (15.9 %) presented with hyperbilirubinemia, and their overall survival was significantly worse than patients in the non-HB group (n = 90). Donor age was significantly higher in the HB group (P < 0.05). Of the 17 patients in the HB group, nine survived. The postoperative serum prothrombin level at the time when the serum bilirubin level was >30 mg/dl was significantly higher in surviving patients (P < 0.01).

CONCLUSIONS

The use of a partial liver graft from an aged donor is a significant risk factor for severe hyperbilirubinemia and a poorer outcome. However, those patients who maintain their liver synthetic function while suffering from hyperbilirubinemia may recover from hyperbilirubinemia and eventually achieve good liver function, thus resulting in a favorable survival.

Liver transplantation using elderly donors: a risk factor analysis

Survival after liver transplantation is negatively impacted by use of elderly deceased donors, but excluding them would increase waiting times and waiting list mortality. We reviewed our experience with liver transplantation (LT) utilizing livers from deceased donors 65 yr of age and older to identify those factors that impact graft survival. All adult patients (≥ 18 yr old) who underwent primary LT using deceased donor livers from donors aged ≥ 65 yr between February 1995 and November 2003 were included. With multivariate analysis we found four unfavorable characteristics significantly associated with higher post-transplant graft failure rate. These characteristics are hepatitis C as an etiology of liver disease, Model for End-Stage Liver Disease score >20, serum glucose level of donor > 200 mg/dL at the time of liver recovery, and skin incision to aortic cross-clamp time > 40 minutes in the donor surgery. The five-yr estimated graft survival rates having 0, 1, 2, 3, and 4 unfavorable characteristics were 100%, 82.0%, 81.7%, 39.3%, and 25.0%, respectively (p < 0.05). Our data demonstrated good graft survival can be achieved in LT using elderly donor liver allografts with appropriate patient selection, donor blood glucose management and efficient liver recovery with minimal manipulation of the liver during donor surgery.

Identification of new donor variables associated with graft survival in a single-center liver transplant cohort

We currently face the more widespread use of marginal livers for organ transplantation. Therefore, it is imperative to adequately identify the factors affecting early and late graft survival in that setting. The objective of this study was to determine the donor variables associated with graft survival in the liver transplant program of the University of Montreal. We retrospectively studied the survival of 634 grafts transplanted into 634 recipients between 1990 and 2008. The variables associated with 1- and 5-year graft survival were identified with the Cox proportional hazards regression model. The donor population was characterized by a mean age of 45.24 ± 18.15 years; 52.8% had at least 1 of the currently recognized extended criteria donor factors. The recipients had a mean age of 52.51 ± 10.80 years and a mean Child-Pugh score of 9.58 ± 2.32. Liver grafts were considered inadequate with respect to their gross appearance in 16 cases (2.5%). The 1- and 5-year graft survival rates were 78.7% and 71.1%, respectively. According to a Cox regression multivariate analysis, the independent determining factors associated with graft survival were (1) the graft appearance (P < 0.001 at 1 and 5 years), (2) the donor partial pressure of oxygen/fraction of inspired oxygen ratio (P = 0.005 at 1 year and P < 0.005 at 5 years), and (3) the donor hemoglobin level (P = 0.008 at 1 year and P = 0.005 at 5 years). In conclusion, the gross graft appearance, the presence of donor lung diffusion abnormalities, and the donor hemoglobin levels were significantly associated with graft survival. These observations, if they are confirmed, could improve our ability to select marginal organs.

Analysis of liver transplant outcomes for United Network for Organ Sharing recipients 60 years old or older identifies multiple model for end-stage liver disease-independent prognostic factors

Older recipient age is associated with worse posttransplant survival. Although the median age of liver disease patients undergoing orthotopic liver transplantation (OLT) continues to rise, prognostic factors for posttransplant survival specific to older patients have not been defined. To address this issue, the United Network for Organ Sharing/Organ Procurement and Transplantation Network outcome database was searched to identify prognostic factors for the 8070 liver recipients 60 years old or older who underwent transplantation from 1994 to 2005. Prognostic factors were assessed with univariate analysis and multivariate modeling. The 5 strongest prognostic variables (ventilator status, diabetes mellitus, hepatitis C virus, creatinine levels >/=1.6 mg/dL, and recipient and donor age >or=120 years) were aggregated to define a novel older recipient prognostic score (ORPS). The overall 1- and 5-year posttransplant survival rates were 83% and 67%, respectively. The risk model, created by the assignment of 1 point to each ORPS factor, stratified patient outcomes into distinct prognostic groups at the 1-, 3-, and 5-year posttransplant time points (P < 0.001). The 5-year survival rates for patients with ORPS values of 0, 1, and 2 points were 75%, 69%, and 58%, respectively. Patients who underwent transplantation with an ORPS > 2 points consistently experienced 5-year survival rates of less than 50%. In conclusion, in liver transplant recipients 60 years old or older, the ORPS was able to predict significant and clinically relevant differences in posttransplant survival. By optimization of donor selection for recipients over the age of 60 years, clinical utilization of the ORPS model may enhance organ utilization for all patients awaiting OLT.

The biopsied donor liver: incorporating macrosteatosis into high-risk donor assessment

To expand the donor liver pool, ways are sought to better define the limits of marginally transplantable organs. The Donor Risk Index (DRI) lists 7 donor characteristics, together with cold ischemia time and location of the donor, as risk factors for graft failure. We hypothesized that donor hepatic steatosis is an additional independent risk factor. We analyzed the Scientific Registry of Transplant Recipients for all adult liver transplants performed from October 1, 2003, through February 6, 2008, with grafts from deceased donors to identify donor characteristics and procurement logistics parameters predictive of decreased graft survival. A proportional hazard model of donor variables, including percent steatosis from higher-risk donors, was created with graft survival as the primary outcome. Of 21,777 transplants, 5051 donors had percent macrovesicular steatosis recorded on donor liver biopsy. Compared to the 16,726 donors with no recorded liver biopsy, the donors with biopsied livers had a higher DRI, were older and more obese, and a higher percentage died from anoxia or stroke than from head trauma. The donors whose livers were biopsied became our study group. Factors most strongly associated with graft failure at 1 year after transplantation with livers from this high-risk donor group were donor age, donor liver macrovesicular steatosis, cold ischemia time, and donation after cardiac death status. In conclusion, in a high-risk donor group, macrovesicular steatosis is an independent risk factor for graft survival, along with other factors of the DRI including donor age, donor race, donation after cardiac death status, and cold ischemia time.

Allocation priority in non-urgent liver transplantation: An overview of proposed scoring systems

Given the lack of donors, a correct organ allocation system for candidates to liver transplantation is essential to increase graft and patient survival. The most used organ allocation tools are Child-Turcotte-Pugh and model for end-stage liver disease. It is generally accepted that model for end-stage liver disease score is superior to the Child-Turcotte-Pugh classification in predicting the short-term survival of cirrhotic patients awaiting liver transplantation. Since 2002, model for end-stage liver disease is widely used for liver allocation. In recent years, to overcome limitations of the consolidated scores, some adjustments to the original model for end-stage liver disease formula and new scoring systems have been proposed. Published data suggest that integrating serum sodium and model for end-stage liver disease may improve the score prognostic accuracy but further studies are necessary to confirm this issue. The updated model for end-stage liver disease, obtained through a revision of traditional model for end-stage liver disease parameters and tested in a large cohort of patients, is of great interest at the moment. In conclusion, several scoring systems have been described for organ allocation, but today, none is definitely able to overcome the limitations of the Child-Turcotte-Pugh and model for end-stage liver disease systems.

Optimal utilization of extended hepatic grafts

Orthotopic liver transplantation has emerged as the standard treatment for end-stage liver disease. In the United States, the number of listed patients has tripled in the last two decades. Organ availability during the same period has plateaued at approximately 6000 grafts annually, resulting in a fivefold increase in wait-list mortality. The problem is not specific to the United States; European and Asian registries report similar shortages. Donor pool expansion strategies such as the use of living donors, cadaveric split livers, and "extended criteria donors"; (ECD) are being pursued. Used judiciously, ECD grafts provide an opportunity for addressing the shortage. Although there is no universally accepted definition of ECD, the term generally refers to donor factors predisposing recipients to poor initial graft function and/or increased long-term risk. These factors include advanced donor age, hypernatremia, prolonged warm ischemic time, pressor requirement, and donation after cardiac death. The transplant community is scrutinizing all factors to evaluate the degree of risk they impart on the recipient and the extent to which grafts can be "matched"; to maintain acceptable outcomes. We review the importance of selected factors and the impact of a "matching"; strategy to minimize recipient risk while optimizing graft use.

Variable activation of phosphoinositide 3-kinase influences the response of liver grafts to ischemic preconditioning

BACKGROUND/AIMS

The efficacy of ischemic preconditioning (IPC) in preventing reperfusion injury in human liver transplants is still questioned. Phosphoinositide-3-kinase (PI3K) is essential for IPC development in rodent livers. This work investigates whether PI3K-dependent signals might account for the inconsistent responses to IPC of transplanted human livers.

METHODS

Forty livers from deceased donors were randomized to receive or not IPC before recovery. PI3K activation was evaluated in biopsies obtained immediately before IPC and 2 h after reperfusion by measuring the phosphorylation of the PI3K downstream kinase PKB/Akt and the levels of the PI3K antagonist phosphatase tensin-homologue deleted from chromosome 10 (PTEN).

RESULTS

IPC increased PKB/Akt phosphorylation (p = 0.01) and decreased PTEN levels (p = 0.03) in grafts, but did not significantly ameliorate post-transplant reperfusion injury. By calculating T(2h)/T(0) PKB/Akt phosphorylation ratios, 10/19 (53%) of the preconditioned grafts had ratios above the control threshold (IPC-responsive), while the remaining nine grafts showed ratios comparable to controls (IPC-non-responsive). T(2h)/T(0) PTEN ratios were also decreased (p < or = 0.03) only in IPC-responsive grafts. The patients receiving IPC-responsive organs had ameliorated (p < or = 0.05) post-transplant aminotransferase and bilirubin levels, while prothrombin activity was unchanged.

CONCLUSIONS

Impaired PI3K signaling might account for the variability in the responses to IPC of human grafts from deceased donors.

D-MELD, a simple predictor of post liver transplant mortality for optimization of donor/recipient matching

Numerous donor and recipient risk factors interact to influence the probability of survival after liver transplantation. We developed a statistic, D-MELD, the product of donor age and preoperative MELD, calculated from laboratory values. Using the UNOS STAR national transplant data base, we analyzed survival for first liver transplant recipients with chronic liver failure from deceased after brain death donors. Preoperative D-MELD score effectively stratified posttransplant survival. Using a cutoff D-MELD score of 1600, we defined a subgroup of donor-recipient matches with significantly poorer short- and long-term outcomes as measured by survival and length of stay (LOS). Avoidance of D-MELD scores above 1600 improved results for subgroups of high-risk patients with donor age >/=60 and those with preoperative MELD >/=30. D-MELD >/=1600 accurately predicted worse outcome in recipients with and without hepatitis C. There is significant regional variation in average D-MELD scores at transplant, however, regions with larger numbers of high D-MELD matches do not have higher survival rates. D-MELD is a simple, highly predictive tool for estimating outcomes after liver transplantation. This statistic could assist surgeons and their patients in making organ acceptance decisions. Applying D-MELD to liver allocation could eliminate many donor/recipient matches likely to have inferior outcome.

Liver transplantations with donors aged 60 years and above: the low liver damage strategy

According to transplant registries, grafts from elderly donors have lower survival rates. During 1999-2005, we evaluated the outcomes of 89 patients who received a liver from a donor aged > or = 60 years and managed with the low liver-damage strategy (LLDS), based on the preoperative donor liver biopsy and the shortest possible ischemia time (group D > or = 60-LLDS). Group D > or = 60-LLDS was compared with 198 matched recipients, whose grafts were not managed with this strategy (89 donors < 60 years, group D < 60-no-LLDS and 89 donors aged > or =60 years, group D > or = 60-no-LLDS). In the donors proposed from the age group of > or =60 years, the number of donors rejected decreased during the study period and the LLDS was found to be responsible for this in a significant manner (47% vs. 60%, respectively P < 0.01). Among the recipients transplanted, the clinical features (age, gender, viral infection, child and model for end-stage liver disease score) were comparable among groups, but group D > or = 60-LLDS had a lower mean ischemia time: 415 +/- 106 min vs. 465 +/- 111 (D < 60-no-LLDS), P < 0.05 and vs. 476 +/- 94 (D > or = 60-no-LLDS), P < 0.05. After a median follow-up of 3 years, the 1- and 3-year graft survival rates of group D > or = 60-LLDS (84% and 76%) were comparable with group D < 60-no-LLDS (89% and 76%) and were significantly higher than group D > or = 60-no-LLDS (71% and 54%), P < 0.005. In conclusion, the LLDS optimized the use of livers from elderly donors.

Liver transplantation using donors older than 80 years: a single-center experience

AIM

The shortage of organs for orthotopic liver transplantation (OLT) has forced transplantation centers to expand the donor pool by using donors traditionally labeled as "extended criteria donors." One such example is OLT using a donor with advanced age.

MATERIALS AND METHODS

We retrospectively evaluated 10 patients who received a liver graft from cadaveric donors older than 80 years. We analyzed pretransplantation donor and recipient characteristics, as well as the evolution of the recipients.

RESULTS

All 10 donors were older than 80 years (median age, 83.5; range, 80-93). No steatosis (>30%) was accepted in the older donor group. Medium follow-up was 19.5 months. The most frequent cause for OLT was hepatitis C virus (HCV) cirrhosis (8/10 patients). We had 1 case of primary nonfunction, 1 patient died immediately after surgery because of extrahepatic complications (cardiac arrest), and 2 other patients had a severe HCV recurrence and died after 1 and 2 years from OLT, respectively. Five patients had HCV recurrence and biliary complications were present in 60% of the patients. No cases of acute or chronic rejection were described. Overall survival rates after 1 and 3 years were 80% and 40%, respectively.

CONCLUSIONS

Old donor age is not an absolute contraindication to OLT. Liver grafts from donors older than 80 years can be used knowing that there is a high risk of postoperative complications. Furthermore, the increased risk of developing severe HCV recurrence, related to older donor age, suggests that such livers should be used in HCV-negative recipients.

Minimizing risk associated with elderly liver donors by matching to preferred recipients

Elderly liver donors (ELDs) represent a possible expansion of the donor pool, although there is great reluctance to use ELDs because of reports that increasing donor age predicts graft loss and patient death. The goal of this study was to identify a subgroup of recipients who would be least affected by increased donor age and thus best suited to receive grafts from ELDs. A national registry of deceased donor liver transplants from 2002-2005 was analyzed. ELDs aged 70-92 (n = 1043) were compared with average liver donors (ALDs) aged 18-69 (n = 15,878) and ideal liver donors (ILDs) aged 18-39 (n = 6842). Recipient factors that modified the effect of donor age on outcomes were identified via interaction term analysis. Outcomes in recipient subgroups were compared using Kaplan-Meier survival analysis. Recipients preferred for ELD transplants were determined to be first-time recipients over the age of 45 with body mass index <35, non-status 1 registration, cold ischemic time <8 hours, and either hepatocellular carcinoma or an indication for transplantation other than hepatitis C. In preferred recipients, there were no differences in outcomes when ELD livers were used (3-year graft survival: ELD 75%, ALD 75%, ILD 77%, P > 0.1; 3-year patient survival: ELD 81%, ALD 80%, ILD 81%, P > 0.1). In contrast, there were significantly worse outcomes when ELD livers were used in nonpreferred recipients (3-year graft survival: ELD 50%, ALD 71%, ILD 75%, P < 0.001; 3-year patient survival: ELD 64%, ALD 77%, ILD 80%, P < 0.001).

CONCLUSION

The risks of ELDs can be substantially minimized by appropriate recipient selection.

Ischemic pre-conditioning in deceased donor liver transplantation: a prospective randomized clinical trial

To assess the immediate and long-term effects of ischemic preconditioning (IPC) in deceased donor. liver transplantation (LT), we designed a prospective, randomized controlled trial involving 60 donors: control group (CTL, n = 30) or study group (IPC, n = 30). IPC was induced by 10-min hiliar clamping immediately before recovery of organs. Clinical data and blood and liver samples were obtained in the donor and in the recipient for measurements. IPC significantly improved biochemical markers of liver cell function such as uric acid, hyaluronic acid and Hypoxia-Induced Factor-1 alpha (HIF-1 alpha) levels. Moreover, the degree of apoptosis was significantly lower in the IPC group. On clinical basis, IPC significantly improved the serum aspartate aminotransferase (AST) levels and reduced the need for reoperation in the postoperative period. Moreover, the incidence of primary nonfunction (PNF) was lower in the IPC group, but did not achieve statistical significance. We conclude that 10-min IPC protects against I/R injury in deceased donor LT.

A cause-specific hazard rate analysis of prognostic factors among 877 adults who received primary orthotopic liver transplantation

BACKGROUND

In orthotopic liver transplantation (OLT) distinct causes of graft failure (GF) and death with a functioning graft (DFG) exist. Prognostic factors for one failure type may be distinctly different from those predictive of other types, and an accurate portrayal of these relationships may more clearly explain each factor's importance.

METHODS

A multivariable cause-specific hazard (CSH) rate analysis using Cox stepwise regression was performed among 877 adults who received primary OLT during 1996-2004 with tacrolimus+steroids as immunosuppression.

RESULTS

Older donor age (P=0.004) implied greater primary dysfunction GF, while primary sclerosing cholangitis (PSC; P=0.0002) implied greater vascular thrombosis GF. Recurrent nonmalignant liver disease GF was higher among hepatitis C virus patients (P<0.00001), and younger recipient age (P=0.005) implied greater death from recurrent (metastatic) hepatocellular carcinoma. African-American race (P<0.00001), PSC (P=0.003), and younger recipient age (P=0.005) were independently associated with greater GF due to chronic rejection. Older donor age (P=0.003) implied greater infection DFG, while older recipient age (P=0.003) and pretransplant diabetes (P=0.03) were independently associated with greater cardiovascular/cerebrovascular DFG. Finally, most of these cause-specific predictors were not significant in an overall Cox model for graft survival.

CONCLUSIONS

The CSH approach should be more widely used in investigations of prognostic factors. The result of older donor age implying greater primary dysfunction GF and infection DFG but having no association with other failure types demonstrates that its impact is specific to the graft's early posttransplant functional status. In addition, while recipient age was an important prognosticator, its direction of association reverses depending upon the outcome being analyzed.

Expanding donor options: marginal, living, and split donors

One of the most important factors in the increasing number of liver transplantations performed in the United States is the growing acceptance of marginal grafts, which are defined as organs at increased risk for poor function or failure that may subject the recipient to greater risks of morbidity or mortality. Based on encouraging results, a growing number of liver transplantation centers are broadening their criteria for transplantation of marginal grafts. This article discusses the use of the extended criteria donor liver, split-liver, and living-donor liver transplantation.

Utilization of extended donor criteria liver allograft: Is the elevated risk of failure independent of the model for end-stage liver disease score of the recipient?

BACKGROUND

The goal of this analysis was to determine if outcomes from the use of extended criteria donor (ECD) livers were dependent upon the Model for End-Stage Liver Disease (MELD) score of the recipient.

METHODS

The Organ Procurement and Transplantation Network (OPTN) database as of March 4, 2006 was used for the analysis. Data from 12,056 adult liver transplant (LTx) recipients between June 1, 2002 and June 30, 2005 was analyzed. The donor risk index (DRI) was calculated as previously reported. A DRI of > or =1.7 was classified as ECD. Relative risk (RR) estimates were derived from Cox regression models adjusted for DRI, recipient MELD, age, sex, ethnicity, diagnosis, and year of transplant.

RESULTS

Data from 2,873 grafts falling in the ECD category (23.8%) and their recipients were analyzed. Recipients with low MELD scores (<15) received the highest proportion of ECD livers (33%). ECD livers were associated with a significant increase in the RR of graft failure within each MELD category. However, this effect held within each of the three MELD categories.

CONCLUSION

The use of ECD grafts expands the organ pool at expense of increased RR of liver failure. Our analysis showed no significant interaction between DRI and MELD score of the recipient. The fact that there is no additional impact of ECD livers in recipients with high MELD scores suggests that this group of patients may benefit from this pool of grafts.

Selective use of older adults in right lobe living donor liver transplantation

Many centers are reluctant to use older donors (>44 years) for adult right-lobe living donor liver transplantation (RLDLT) due to concerns about possible increased morbidity in donors and poorer outcomes in recipients. Since 2000, 130 adult RLDLTs have been performed at our institution. Recipients were divided into those who received a right lobe graft from a donor </=age 44 (n = 89, 68%; median age 30) and those who received a liver graft from a donor age >44 (n = 41, 32%; mean age 52). The two donor and recipient populations had similar demographic and operative profiles. With a median follow-up of 29 months, the severity and number of complications in older donors were similar to those in younger donors. No living donor died. Older donor allografts had initial allograft dysfunction compared to younger donors. Complication rates were similar among recipients in both groups but there was a higher bile duct stricture rate with older donor grafts (27% vs. 12%; p = 0.04). One-year recipient graft survival was 86% for older donors and 85% for younger donors (p = 0.95). Early experience with the use of selected older adults (>44 years) for RLDLT is encouraging, but may be associated with a higher rate of biliary complications in the recipient.

Mild hepatic steatosis is not a major risk factor for hepatectomy and regenerative power is not impaired

BACKGROUND

An understanding of the regeneration power and operative risk of steatotic livers after hepatectomy is still unclear. We evaluated the volume regeneration and outcome of steatotic livers after donor hepatectomy.

METHODS

Fifty-four, consecutive living liver donors from September 2002 to December 2003 were evaluated prospectively by volumetric analysis, liver-spleen ratio, and liver attenuation index; the latter has been shown by serial computed tomographic scanning to be correlated strongly with histologic steatosis. Donors were followed up completely for at least 1 year (460-915 days) and were allocated according to histologic degree of macrovesicular steatosis: group 1, <5% (n = 36); group 2, 5%-30% (n = 18).

RESULTS

No mortality or hepatic failure was observed, and no donor required reoperation or intraoperative transfusion. The results of serial liver function tests, and major and minor morbidities were comparable between groups. Liver-spleen ratio and liver attenuation index remained at a constant level above normal values postoperatively in group 1, but increased rapidly above normal values in group 2. No difference in the rate of liver regeneration at 10 days after hepatectomy was found between the groups (P = .487), but the liver regeneration rate at 3 months after hepatectomy in group 1 was slightly higher than that in group 2 (P < .044). However, no difference was observed between the 2 groups at 1 year after hepatectomy (P = .4).

CONCLUSIONS

Mild hepatic steatosis is cleared immediately after hepatectomy, and early regeneration power is impaired, but the long-term regenerative power is comparable. Hepatectomy in donors with mild steatosis can be performed with low morbidity.

Characteristics associated with liver graft failure: the concept of a donor risk index

Transplant physicians and candidates have become increasingly aware that donor characteristics significantly impact liver transplantation outcomes. Although the qualitative effect of individual donor variables are understood, the quantitative risk associated with combinations of characteristics are unclear. Using national data from 1998 to 2002, we developed a quantitative donor risk index. Cox regression models identified seven donor characteristics that independently predicted significantly increased risk of graft failure. Donor age over 40 years (and particularly over 60 years), donation after cardiac death (DCD), and split/partial grafts were strongly associated with graft failure, while African-American race, less height, cerebrovascular accident and 'other' causes of brain death were more modestly but still significantly associated with graft failure. Grafts with an increased donor risk index have been preferentially transplanted into older candidates (>50 years of age) with moderate disease severity (nonstatus 1 with lower model for end-stage liver disease (MELD) scores) and without hepatitis C. Quantitative assessment of the risk of donor liver graft failure using a donor risk index is useful to inform the process of organ acceptance.

Liver Transplantation in Italy: Analysis of Risk Factors Associated with Graft Outcome

Objective

To analyze the graft outcome after liver transplantation in Italy in the years 1995 to 2000.

Methods

We performed a longitudinal study with follow-up at 3 months, 1 year, 3 years, and 5 years on 1987 liver grafts. The effect of several variables on graft survival was also analyzed.

Results

Several variables affect graft survival: Donor and recipient older age, gender mismatching, prolonged cold ischemia time, acute hepatic necrosis, and retransplantation are reported to significantly affect liver graft survival. Donors older than 60 years show a relative risk of 1.59 (95% CI, 1.23–2.05) compared with donors with an age between 19 and 60 years; recipients older than 50 years show a relative risk of 1.29 (95% CI, 1.04–1.60) compared with recipients aged 19 to 50 years. A cold ischemia time of 12 hours or longer doubled the risk of failure (relative risk = 2.01, 95% CI, 1.36–2.96) compared with a cold ischemia time of less than 6 hours.

Conclusions

The results show that the overall quality of liver transplantation in Italy is satisfying and comparable to the outcome reported by international registries. Follow-up studies on large numbers of liver transplants are useful to define predictors of outcome, and subsequently modify the criteria for organ allocation.

Donors older than 70 years in liver transplantation

INTRODUCTION

Expansion of donor criteria has become necessary with the increasing number of liver transplantation candidates, as aged donors who have been considered to yield marginal organs.

METHODS

Our database of 477 liver transplants (OLT) included 55 cases performed from donors at least 70 years old vs 422 with younger donors. We analyzed pretransplantation donor and recipient characteristics as well as evolution of the recipients.

RESULTS

The old donor group showed significantly lower ALT (23 +/- 17 vs 48.9 +/- 67; P = .0001) and LDH (444 +/- 285 vs 570 +/- 329; P = .01). There was a trend toward fewer hypotensive events in the aged donor group (27.2% vs 40.5%; P = .07). No steatosis (>10%) was accepted in the old donor group. Cold ischemia time was statistically shorter for the aged donors (297 +/- 90 minutes vs 346 +/- 139 minutes; P = .03). With these selected donors, the results were not different for primary nonfunction, arterial and biliary complications, hospitalization, acute reoperation or acute retransplantation, and hospital mortality when donors > or =70 years old were compared to younger donors. Functional cholestasis, neither related to rejection nor to biliary complications, was seen more frequently in old donor recipients (40% vs 22%; P = .03). No differences in 1, and 3 year survivals were observed between recipients of donors over 70 years old and these of younger organs: 93.8% and 90.6% vs 90.7% and 82.8%, respectively.

CONCLUSION

When using selected donors > or =70 years old the outcomes were comparable to those obtained with younger donors. Strict selection is necessary to achieve good long-term survival.

Does the liver ever age? Results of liver transplantation with donors above 80 years of age

INTRODUCTION

Facing an increasing shortage of donor organs, donor criteria become more extended and so-called marginal organs are accepted for transplantation. For liver donation donor age above 70 years is accepted as a risk factor concerning primary dysfunction or nonfunction. Therefore, the aim of this study was to compare the early outcome of grafts older versus younger than 80 years of age.

PATIENTS AND METHOD

Between August 2002 and February 2004, 40 adult liver transplants were performed using triple immunosuppression with tacrolimus, MMF, and low-dose corticosteroids. Recipients with HCC received low-dose rapamycin after postoperative day 14. The outcome of grafts from donors under 80 years of age (n=35) was compared with those from donors 80 years old or more (n=5). For statistical analysis Mann-Whitney-U-Test and Fisher's Exact Test were used with P < .05 considered statistically significant.

RESULTS

The average donor age of our population was 54.4 +/- 17.3 years with five donors older than 80 years (80-83 years). These donors all had additional risk factors. The recipients of the latter grafts suffered from HCC and liver cirrhosis Child A (n=2) or from viral hepatitis (n=3). One recipient had advanced cirrhosis with severe complications. The outcomes of both groups were comparable concerning intraoperative and postoperative courses. All recipients of old liver grafts left the hospital with stable graft function.

CONCLUSION

Liver grafts over 80 years can be transplanted with good results, especially if given to recipients with malignancy and otherwise stable liver function.

Older liver graft transplantation, cholestasis and synthetic graft function

Older liver grafts are often discarded because of conservative selection criteria. We report on our clinical experience with graft-age related outcome. Patients transplanted with livers older than 70 years (70.2-80.2 years, n = 38) were compared with controls transplanted with livers younger than 70 years. Pairs were matched for age, gender, indication and cold ischemic time. Mean donor age was 73.4 +/- 2 vs. 39 +/- 16 years. Patient and graft survival did not differ between both groups after 1-year follow-up (P = 0.19 and P = 0.24 respectively). Retransplantation rate was 10.5% vs. 5.3% (P = 0.40). Initial poor function occurred in two patients in the study group versus four patients in the control group (P = 0.69). The incidence of rejection episodes was comparable. Parameters of cholestasis and protein synthesis showed no difference 1-year post-transplant. Mean age of donor organs in matched pairs group B was near by half of that in the older donor group A (39.0 vs. 73.4 years). Post-transplant outcome as indicated by patient and graft survival was comparable between both groups. Donor organ age had no impact on postoperative organ function. We recommend to accept liver grafts from organ donors older than 70 years to expand the donor pool.

Organ donation and utilization in the United States, 2004

This article discusses issues directly related to the organ donation process, including donor consent, donor medical suitability, non-recovery of organs, organs recovered but not transplanted, expanded criteria donors (ECD), and donation after cardiac death (DCD). The findings and topics covered have important implications for how to evaluate and share best practices of organ donation as implemented by organ procurement organizations (OPOs) and major donor hospitals in the same donation service areas (DSAs). In 2002 and 2003, US hospitals referred more than one million deaths or imminent deaths to the OPOs of their DSA. Referrals increased by nearly 10% from 2002 to 2003 (1,022,280 to 1,121,392). Donor consents have increased by about 5% and the number of total deceased donors has risen from 6,187 to 6,455. Since multiple organs are recovered from most donors, this increase allowed more than 500 additional wait-listed candidates to receive an organ transplant than in the prior year. Non-traditional donor sources have experienced a large rate of increase; in 2003 the number of ECD kidney donors increased by 8% and the number of DCD donors increased by 43%, from 189 donors in year 2002 to 271 donors in 2003.

Preharvest donor hyperoxia predicts good early graft function and longer graft survival after liver transplantation

A total of 44 donor/recipient perioperative and intraoperative variables were prospectively analyzed in 89 deceased-donor liver transplantations classified as initial good graft function (IGGF) or initial poor graft function (IPGF) according to a scoring system based on values obtained during the 1st 72 postoperative hours from the serum alanine aminotransferase (ALT) concentration, bile output, and prothrombin activity. The IGGF compared with the IPGF group showed: 1) longer graft (P = .002) and patient (P = .0004) survival; 2) at univariate analysis, a higher (mean [95% confidence interval]) preharvest donor arterial partial pressure of oxygen (PaO(2)) (152 [136-168] and 104 [91-118] mmHg, respectively; P = .0008) and arterial hemoglobin oxygen saturation (97.9 [97.2-98.7] and 96.7 [95.4-98.0]%, respectively; P = .0096), a lower percentage of donors older than 65 years (13 and 33%, respectively; P = .024), a lower percentage of donors treated with noradrenaline (16 and 41%, respectively; P = .012). At multivariate analysis, IGGF was associated positively with donor PaO(2) and negatively with donor age greater than 65 years and with donor treatment with noradrenaline. Independently from the grouping according to initial graft function, graft survival was longer when donor PaO(2) was >150 mmHg than when donor PaO(2) was < or =150 mmHg (P = .045). In conclusion, preharvest donor hyperoxia predicts IGGF and longer graft survival.