Tranexamic acid versus placebo to reduce perioperative blood transfusion in patients undergoing liver resection: protocol for the haemorrhage during liver resection tranexamic acid (HeLiX) randomised controlled trial

INTRODUCTION

Despite use of operative and non-operative interventions to reduce blood loss during liver resection, 20%-40% of patients receive a perioperative blood transfusion. Extensive intraoperative blood loss is a major risk factor for postoperative morbidity and mortality and receipt of blood transfusion is associated with serious risks including an association with long-term cancer recurrence and overall survival. In addition, blood products are scarce and associated with appreciable expense; decreasing blood transfusion requirements would therefore have health system benefits. Tranexamic acid (TXA), an antifibrinolytic, has been shown to reduce the probability of receiving a blood transfusion by one-third for patients undergoing cardiac or orthopaedic surgery. However, its applicability in liver resection has not been widely researched.

METHODS AND ANALYSIS

This protocol describes a prospective, blinded, randomised controlled trial being conducted at 10 sites in Canada and 1 in the USA. 1230 eligible and consenting participants will be randomised to one of two parallel groups: experimental (2 g of intravenous TXA) or placebo (saline) administered intraoperatively. The primary endpoint is receipt of blood transfusion within 7 days of surgery. Secondary outcomes include blood loss, postoperative complications, quality of life and 5-year disease-free and overall survival.

ETHICS AND DISSEMINATION

This trial has been approved by the research ethics boards at participating centres and Health Canada (parent control number 177992) and is currently enrolling participants. All participants will provide written informed consent. Results will be distributed widely through local and international meetings, presentation, publication and ClinicalTrials.gov.

TRIAL REGISTRATION NUMBER

NCT02261415.

Chronic stress physically spares but functionally impairs innate-like invariant T cells

The deleterious effects of psychological stress on mainstream T lymphocytes are well documented. However, how stress impacts innate-like T cells is unclear. We report that long-term stress surprisingly abrogates both T helper 1 (T_H1)- and T_H2-type responses orchestrated by invariant natural killer T (iNKT) cells. This is not due to iNKT cell death because these cells are unusually refractory to stress-inflicted apoptosis. Activated iNKT cells in stressed mice exhibit a “split” inflammatory signature and trigger sudden serum interleukin-10 (IL-10), IL-23, and IL-27 spikes. iNKT cell dysregulation is mediated by cell-autonomous glucocorticoid receptor signaling and corrected upon habituation to predictable stressors. Importantly, under stress, iNKT cells fail to potentiate cytotoxicity against lymphoma or to reduce the burden of metastatic melanoma. Finally, stress physically spares mouse mucosa-associated invariant T (MAIT) cells but hinders their T_H1-/T_H2-type responses. The above findings are corroborated in human peripheral blood and hepatic iNKT/MAIT cell cultures. Our work uncovers a mechanism of stress-induced immunosuppression.

Invariant T cells are emergency responders to infection and cancer. Rudak et al. report that psychological stress unusually spares these innate-like T lymphocytes but alters or impairs their cytokine production and cytotoxic and/or antimetastatic capacities through a cell-autonomous, glucocorticoid receptor-dependent mechanism. This may explain certain aspects of stress-induced immunosuppression.

An Addition of U0126 Protecting Heart Grafts From Prolonged Cold Ischemia-Reperfusion Injury in Heart Transplantation: A New Preservation Strategy

BACKGROUND

Ischemia-reperfusion injury (IRI) is the major cause of primary graft dysfunction in organ transplantation. The mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) signaling pathway plays a crucial role in cell physiological and pathological processes including IRI. This study aims to investigate whether inhibition of ERK signaling with U0126 can prevent prolonged cold IRI in heart transplantation.

METHODS

Rat cardiac cell line H9c2 cells were treated with U0126 before exposure to hypothermic hypoxia/reoxygenation (H/R) conditions. The effect of U0126 on H9c2 cells in response to H/R stress was determined by measuring cell death, reactive oxygen species production, mitochondrial membrane potential, and ERK signaling activation. Mouse syngeneic heterotopic heart transplantation was conducted, where a donor heart was preserved in the University of Wisconsin (UW) solution supplemented with U0126 for 24 hours at 4°C before transplantation. Heart graft function, histopathologic changes, apoptosis, and fibrosis were measured to assess IRI.

RESULTS

Phosphorylated ERK was increased in both in vitro H/R-injured H9c2 cells and in vivo heart grafts with IRI. Pretreatment with U0126 inhibited ERK phosphorylation and prevented H9c2 cells from cell death, reactive oxygen species generation, and mitochondrial membrane potential loss in response to H/R. Preservation of donor hearts with U0126-supplemented solution improved graft function and reduced IRI by reductions in cell apoptosis/death, neutrophil infiltration, and fibrosis of the graft.

CONCLUSIONS

Addition of U0126 to UW solution reduces ERK signal activation and attenuates prolonged cold IRI in a heart transplantation model. ERK inhibition with U0126 may be a useful strategy to minimize IRI in organ transplantation.

Blood pressure control according to clinical practice guidelines is associated with decreased mortality and cardiovascular events among liver transplant recipients

Data for liver transplant recipients (LTRs) regarding the benefit of care concordant with clinical practice guidelines for management of blood pressure (BP) are sparse. This paper reports on clinician adherence with BP clinical practice guideline recommendations and whether BP control is associated with mortality and cardiovascular events (CVEs) among LTRs. We conducted a longitudinal cohort study of adult LTRs who survived to hospital discharge at a large tertiary care network between 2010 and 2016. The primary exposure was a BP of <140/<90 mm Hg within year 1 of LT. Among 602 LTRs (mean age 56.7 years, 64% men), 92% had hypertension and 38% had new onset hypertension. Less than 30% of LTRs achieved a BP of <140/<90 mm Hg over a mean of 43.2 months. In multivariable models, adjusted for key confounders, BP control post-LT compared with lack of control was associated with a significantly lower hazard of mortality (hazard ratio [HR] 0.48, 95% confidence interval [CI] 0.39, 0.87) and of CVEs (HR 0.65, 95% CI 0.43, 0.97). The association between BP control of <140/<90 mm Hg with improved survival and decreased CVEs in LTRs suggests that efforts to improve clinician adherence to BP clinical practice recommendations should be intensified.

Real-World Study of Once-Daily, Extended-Release Tacrolimus Versus Twice-Daily, Immediate-Release Tacrolimus in Kidney Transplantation: Clinical Outcomes and Healthcare Resource Utilization

INTRODUCTION

Real-world data with extended-release tacrolimus (ER-T) are lacking in the USA. This study examined clinical outcomes and healthcare resource utilization in kidney transplant patients receiving ER-T in clinical practice.

METHODS

This was a retrospective, single-center analysis (February-June 2016) using data from Northwestern University's Enterprise Data Warehouse. Adult patients receiving a kidney transplant in the preceding 4 years, treated de novo or converted to ER-T from immediate-release tacrolimus (IR-T) within 10 days post-transplantation, and maintained on ER-T (at least 3 months) were included. Patients were matched for demographic and clinical characteristics with IR-T-treated control patients. Endpoints included clinical outcomes and healthcare resource utilization up to 1 year post-transplantation.

RESULTS

A total of 19 ER-T-treated patients were matched with 55 IR-T-treated patients. No ER-T-treated patients experienced biopsy-confirmed acute rejection (BCAR) or graft failure versus 3 (5.5%) and 3 (5.5%) IR-T-treated patients, respectively. Mean estimated glomerular filtration rate (eGFR), the number of all-cause outpatient visits, readmissions, and all-cause hospitalization days were comparable between groups. Tacrolimus trough levels, days to target level (6-10 ng/mL), and number of required dose adjustments were also similar.

CONCLUSION

Real-world clinical outcomes and healthcare resource utilization were similar with ER-T and IR-T. Larger studies will need to investigate the trend toward fewer BCAR events, and increased graft survival with ER-T.

FUNDING

Astellas Pharma Global Development, Inc. Plain language summary available for this article.

Mucosa-associated invariant T cells infiltrate hepatic metastases in patients with colorectal carcinoma but are rendered dysfunctional within and adjacent to tumor microenvironment

Mucosa-associated invariant T (MAIT) cells are innate-like T lymphocytes that are unusually abundant in the human liver, a common site of colorectal carcinoma (CRC) metastasis. However, whether they contribute to immune surveillance against colorectal liver metastasis (CRLM) is essentially unexplored. In addition, whether MAIT cell functions can be impacted by chemotherapy is unclear. These are important questions given MAIT cells' potent immunomodulatory and inflammatory properties. Herein, we examined the frequencies and functions of peripheral blood, healthy liver tissue, tumor-margin and tumor-infiltrating MAIT cells in 21 CRLM patients who received no chemotherapy, FOLFOX, or a combination of FOLFOX and Avastin before they underwent liver resection. We found that MAIT cells, defined as CD3ε+Vα7.2+CD161++ or CD3ε+MR1 tetramer+ cells, were present within both healthy and tumor-afflicted hepatic tissues. Paired and grouped analyses of samples revealed the physical proximity of MAIT cells to metastatic lesions to drastically influence their functional competence. Accordingly, unlike those residing in the healthy liver compartment, tumor-infiltrating MAIT cells failed to produce IFN-γ in response to a panel of TCR and cytokine receptor ligands, and tumor-margin MAIT cells were only partially active. Furthermore, chemotherapy did not account for intratumoral MAIT cell insufficiencies. Our findings demonstrate for the first time that CRLM-penetrating MAIT cells exhibit wide-ranging functional impairments, which are dictated by their physical location but not by preoperative chemotherapy. Therefore, we propose that MAIT cells may provide an attractive therapeutic target in CRC and that their ligands may be combined with chemotherapeutic agents to treat CRLM.

A point-based prediction model for cardiovascular risk in orthotopic liver transplantation: The CAR-OLT score

Cardiovascular disease (CVD) complications are important causes of morbidity and mortality after orthotopic liver transplantation (OLT). There is currently no preoperative risk-assessment tool that allows physicians to estimate the risk for CVD events following OLT. We sought to develop a point-based prediction model (risk score) for CVD complications after OLT, the Cardiovascular Risk in Orthotopic Liver Transplantation risk score, among a cohort of 1,024 consecutive patients aged 18-75 years who underwent first OLT in a tertiary-care teaching hospital (2002-2011). The main outcome measures were major 1-year CVD complications, defined as death from a CVD cause or hospitalization for a major CVD event (myocardial infarction, revascularization, heart failure, atrial fibrillation, cardiac arrest, pulmonary embolism, and/or stroke). The bootstrap method yielded bias-corrected 95% confidence intervals for the regression coefficients of the final model. Among 1,024 first OLT recipients, major CVD complications occurred in 329 (32.1%). Variables selected for inclusion in the model (using model optimization strategies) included preoperative recipient age, sex, race, employment status, education status, history of hepatocellular carcinoma, diabetes, heart failure, atrial fibrillation, pulmonary or systemic hypertension, and respiratory failure. The discriminative performance of the point-based score (C statistic = 0.78, bias-corrected C statistic = 0.77) was superior to other published risk models for postoperative CVD morbidity and mortality, and it had appropriate calibration (Hosmer-Lemeshow P = 0.33).

CONCLUSION

The point-based risk score can identify patients at risk for CVD complications after OLT surgery (available at www.carolt.us); this score may be useful for identification of candidates for further risk stratification or other management strategies to improve CVD outcomes after OLT. (Hepatology 2017;66:1968-1979).

Applying the WHO conceptual framework for the International Classification for Patient Safety to a surgical population

OBJECTIVE

Efforts to improve patient safety are challenged by the lack of universally agreed upon terms. The International Classification for Patient Safety (ICPS) was developed by the World Health Organization for this purpose. This study aimed to test the applicability of the ICPS to a surgical population.

DESIGN

A web-based safety debriefing was sent to clinicians involved in surgical care of abdominal organ transplant patients. A multidisciplinary team of patient safety experts, surgeons and researchers used the data to develop a system of classification based on the ICPS. Disagreements were reconciled via consensus, and a codebook was developed for future use by researchers.

RESULTS

A total of 320 debriefing responses were used for the initial review and codebook development. In total, the 320 debriefing responses contained 227 patient safety incidents (range: 0-7 per debriefing) and 156 contributing factors/hazards (0-5 per response). The most common severity classification was 'reportable circumstance,' followed by 'near miss.' The most common incident types were 'resources/organizational management,' followed by 'medical device/equipment.' Several aspects of surgical care were encompassed by more than one classification, including operating room scheduling, delays in care, trainee-related incidents, interruptions and handoffs.

CONCLUSIONS

This study demonstrates that a framework for patient safety can be applied to facilitate the organization and analysis of surgical safety data. Several unique aspects of surgical care require consideration, and by using a standardized framework for describing concepts, research findings can be compared and disseminated across surgical specialties. The codebook is intended for use as a framework for other specialties and institutions.

Impact of renal impairment on cardiovascular disease mortality after liver transplantation for nonalcoholic steatohepatitis cirrhosis

BACKGROUND & AIMS

Non-alcoholic steatohepatitis (NASH) is an independent risk factor for cardiovascular disease (CVD) morbidity after liver transplantation, but its impact on CVD mortality is unknown. We sought to assess the impact of NASH on CVD mortality after liver transplantation and to predict which NASH recipients are at highest risk of a CVD-related death following a liver transplant.

METHODS

Using the Organ Procurement and Transplantation Network database, we examined associations between NASH and post-liver transplant CVD mortality, defined as primary cause of death from thromboembolism, arrhythmia, heart failure, myocardial infarction or stroke. A physician panel reviewed cause of death.

RESULTS

Of 48 360 liver transplants (2/2002-12/2011), 5057 (10.5%) were performed for NASH cirrhosis. NASH recipients were more likely to be older, female, obese, diabetic and have history of renal failure or prior CVD vs. non-NASH (P < 0.001 for all). Although there was no difference in overall all-cause mortality (log-rank P = 0.96), both early (30-day) and long-term CVD-specific mortality was increased among NASH recipients (Odds ratio = 1.30, 95% Confidence interval (CI): 1.02-1.66; Hazard ratio = 1.42, 95% CI: 1.07-1.41 respectively). These associations were no longer significant after adjustment for pre-transplant diabetes, renal impairment or CVD. A risk score comprising age ≥55, male sex, diabetes and renal impairment was developed for prediction of post-liver transplant CVD mortality (c-statistic 0.60).

CONCLUSION

NASH recipients have an increased risk of CVD mortality after liver transplantation explained by a high prevalence of comorbid cardiometabolic risk factors that in aggregate identify those at highest risk of post-transplant CVD mortality.

Organ Procurement

Improvements in immunosuppression, organ preservation, surgical technique, and recipient management have led to the widespread adoption of transplantation as a viable therapeutic option for end-stage organ disease. Consequently, more patients than ever are benefiting from organ transplantation. Unfortunately, the rate of organ donation has not kept pace with the increase in the number of recipients awaiting transplantation. The relative shortage of organs has necessitated an increasing reliance on creative strategies aimed at broadening or expanding the limits of the donor pool. For instance, organs now are frequently obtained from so-called extended-criteria donors (i.e., donors who are elderly or who have significant comorbid conditions) or from non-heart-beating donors. A particularly important strategy for alleviating the organ shortage has been the broader application of living donor transplantation. The authors outline the current state of organ procurement from both cadaveric and living donors, including donor evaluation, perioperative management, and the various donor procedures. This review contains 14 figures, 1 table, and 63 references.

Improving Geographic Equity in Kidney Transplantation Using Alternative Kidney Sharing and Optimization Modeling

The national demand for kidney transplantation far outweighs the supply of kidney organs. Currently, a patient's ability to receive a kidney transplant varies depending on where he or she seeks transplantation. This reality is in direct conflict with a federal mandate from the Department of Health and Human Services. We analyze current kidney allocation and develop an alternative kidney sharing strategy using a multiperiod linear optimization model, KSHARE. KSHARE aims to improve geographic equity in kidney transplantation while also respecting transplant system constraints and priorities. KSHARE is tested against actual 2000–2009 kidney allocation using Organ Procurement and Transplant Network data. Geographic equity is represented by minimizing the range in kidney transplant rates around local areas of the country. In 2009, less than 25% of standard criteria donor kidneys were allocated beyond the local area of procurement, and Donor Service Area kidney transplantation rates varied from 3.0% to 30.0%, for an overall range of 27.0%. Given optimal sharing of kidneys within 600 miles of procurement for 2000–2009, kidney transplant rates vary from 5.0% to 12.5% around the country for an overall kidney transplant range of 7.5%. Nationally sharing kidneys optimally between local areas only further decreases the transplant rate range by 1.7%. Enhancing the practice of sharing kidneys by the KSHARE model may increase geographic equity in kidney transplantation.

High early cardiovascular mortality after liver transplantation

Cardiovascular disease (CVD) contributes to excessive long-term mortality after liver transplantation (LT); however, little is known about early postoperative CVD mortality in the current era. In addition, there is no model for predicting early postoperative CVD mortality across centers. We analyzed adult recipients of primary LT in the Organ Procurement and Transplantation Network (OPTN) database between February 2002 and December 2012 to assess the prevalence and predictors of early (30-day) CVD mortality, which was defined as death from arrhythmia, heart failure, myocardial infarction, cardiac arrest, thromboembolism, and/or stroke. We performed logistic regression with stepwise selection to develop a predictive model of early CVD mortality. Sex and center volume were forced into the final model, which was validated with bootstrapping techniques. Among 54,697 LT recipients, there were 1576 deaths (2.9%) within 30 days. CVD death was the leading cause of 30-day mortality (40.2%), and it was followed by infection (27.9%) and graft failure (12.2%). In a multivariate analysis, 9 significant covariates (6 recipient covariates, 2 donor covariates, and 1 operative covariate) were identified: age, preoperative hospitalization, intensive care unit status, ventilator status, calculated Model for End-Stage Liver Disease score, portal vein thrombosis, national organ sharing, donor body mass index, and cold ischemia time. The model showed moderate discrimination (C statistic = 0.66, 95% confidence interval = 0.63-0.68). In conclusion, we provide the first multicenter prognostic model for the prediction of early post-LT CVD death, the most common cause of early post-LT mortality in the current transplant era. However, evaluations of additional CVD-related variables not collected by the OPTN are needed in order to improve the model's accuracy and potential clinical utility.

Detection of medical errors in kidney transplantation: a pilot study comparing proactive clinician debriefings to a hospital-wide incident reporting system

BACKGROUND

Rates of medical errors and adverse events remain high for patients who undergo kidney transplantation; they are particularly vulnerable because of the complexity of their disease and the kidney transplantation procedure. Although institutional incident-reporting systems are used in hospitals around the country, they often fail to capture a substantial proportion of medical errors. The goal of this study was to assess the ability of a proactive, web-based clinician safety debriefing to augment the information about medical errors and adverse events obtained via traditional incident reporting systems.

METHODS

Debriefings were sent to all individuals listed on operating room personnel reports for kidney transplantation surgeries between April 2010 and April 2011, and incident reports were collected for the same time period. The World Health Organization International Classification for Patient Safety was used to classify all issues reported.

RESULTS

A total of 270 debriefings reported 334 patient safety issues (179 safety incidents, 155 contributing factors), and 57 incident reports reported 92 patient safety issues (56 safety incidents, 36 contributing factors). Compared with incident reports, more attending physicians completed the debriefings (32.0 vs 3.5%).

DISCUSSION

The use of a proactive, web-based debriefing to augment an incident reporting system in assessing safety risks in kidney transplantation demonstrated increased information, more perspectives of a single safety issue, and increased breadth of participants.

Comparative effectiveness of liver transplant strategies for end-stage liver disease patients on renal replacement therapy

There are complex risk-benefit tradeoffs with different transplantation strategies for end-stage liver disease patients on renal support. Using a Markov discrete-time state transition model, we compared survival for this group with 3 strategies: simultaneous liver-kidney (SLK) transplantation, liver transplantation alone (LTA) followed by immediate kidney transplantation if renal function did not recover, and LTA followed by placement on the kidney transplant wait list. Patients were followed for 30 years from the age of 50 years. The probabilities of events were synthesized from population data and clinical trials according to Model for End-Stage Liver Disease (MELD) scores (21-30 and >30) to estimate input parameters. Sensitivity analyses tested the impact of uncertainty on survival. Overall, the highest survival rates were seen with SLK transplantation for both MELD score groups (82.8% for MELD scores of 21-30 and 82.5% for MELD scores > 30 at 1 year), albeit at the cost of using kidneys that might not be needed. Liver transplantation followed by kidney transplantation led to higher survival rates (77.3% and 76.4%, respectively, at 1 year) than placement on the kidney transplant wait list (75.1% and 74.3%, respectively, at 1 year). When uncertainty was considered, the results indicated that the waiting time and renal recovery affected conclusions about survival after SLK transplantation and liver transplantation, respectively. The subgroups with the longest durations of pretransplant renal replacement therapy and highest MELD scores had the largest absolute increases in survival with SLK transplantation versus sequential transplantation. In conclusion, the findings demonstrate the inherent tension in choices about the use of available kidneys and suggest that performing liver transplantation and using renal transplantation only for those who fail to recover their native renal function could free up available donor kidneys. These results could inform discussions about transplantation policy.

Program-specific reports: implications and impact on program behavior

PURPOSE OF REVIEW

Measuring and monitoring transplant center performance is vital to ongoing quality assessment and performance improvement initiatives geared toward ensuring optimal care for patients with end-stage organ failure. The impact of regulatory oversight on transplant center behavior and programmatic decision-making is complex.

RECENT FINDINGS

Program-specific reports (PSRs) are published by the Scientific Registry for Transplant Recipients (SRTR) and are publically available for use by a variety of stakeholders, including patients, regulators, insurers, and care providers. PSRs have been both groundbreaking and controversial. The principal areas of concern relate to potential unintended consequences of PSRs, limitations in both the data collected by the registry and the currently used statistical methodology employed by the SRTR for risk adjustment, and the subsequent impact on transplant program behavior.

SUMMARY

PSRs, which serve the purposes of fueling ongoing performance improvement initiatives and informing consumers and payers by fostering transparency in the communication of risk, also involve trade-offs because of their unintended use for regulatory oversight and subsequent impact on transplant center behavior. Future research is necessary to improve data integrity and risk-adjustment methodologies which will enhance regulation and preserve access to transplantation among vulnerable patient populations.

NUTORC-a transdisciplinary health services and outcomes research team in transplantation

The field of solid organ transplantation has historically concentrated research efforts on basic science and translational studies. However, there has been increasing interest in health services and outcomes research. The aim was to build an effective and sustainable, inter- and transdisciplinary health services and outcomes research team (NUTORC), that leveraged institutional strengths in social science, engineering, and management disciplines, coupled with an international recognized transplant program. In 2008, leading methodological experts across the university were identified and intramural funding was obtained for the NUTORC initiative. Inter- and transdisciplinary collaborative teams were created across departments and schools within the university. Within 3 years, NUTORC became fiscally sustainable, yielding more than tenfold return of the initial investment. Academic productivity included funding for 39 grants, publication of 60 manuscripts, and 166 national presentations. Sustainable educational opportunities for students were created. Inter- and transdisciplinary health services and outcomes research in transplant can be innovative and sustainable.

Comparative effectiveness of donation after cardiac death versus donation after brain death liver transplantation: Recognizing who can benefit

Due to organ scarcity and wait-list mortality, transplantation of donation after cardiac death (DCD) livers has increased. However, the group of patients benefiting from DCD liver transplantation is unknown. We studied the comparative effectiveness of DCD versus donation after brain death (DBD) liver transplantation. A Markov model was constructed to compare undergoing DCD transplantation with remaining on the wait-list until death or DBD liver transplantation. Differences in life years, quality-adjusted life years (QALYs), and costs according to candidate Model for End-Stage Liver Disease (MELD) score were considered. A separate model for hepatocellular carcinoma (HCC) patients with and without MELD exception points was constructed. For patients with a MELD score <15, DCD transplantation resulted in greater costs and reduced effectiveness. Patients with a MELD score of 15 to 20 experienced an improvement in effectiveness (0.07 QALYs) with DCD liver transplantation, but the incremental cost-effectiveness ratio (ICER) was >$2,000,000/QALY. Patients with MELD scores of 21 to 30 (0.25 QALYs) and >30 (0.83 QALYs) also benefited from DCD transplantation with ICERs of $478,222/QALY and $120,144/QALY, respectively. Sensitivity analyses demonstrated stable results for MELD scores <15 and >20, but the preferred strategy for the MELD 15 to 20 category was uncertain. DCD transplantation was associated with increased costs and reduced survival for HCC patients with exception points but led to improved survival (0.26 QALYs) at a cost of $392,067/QALY for patients without exception points. In conclusion, DCD liver transplantation results in inferior survival for patients with a MELD score <15 and HCC patients receiving MELD exception points, but provides a survival benefit to patients with a MELD score >20 and to HCC patients without MELD exception points.

Long-term kidney allograft function and survival in prednisone-free regimens: tacrolimus/mycophenolate mofetil versus tacrolimus/sirolimus

BACKGROUND AND OBJECTIVES

The optimal maintenance immunosuppressive regimen to improve long-term renal allograft function and graft survival is yet to be determined.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This observational study prospectively compared tacrolimus/sirolimus with tacrolimus/mycophenolate mofetil in renal transplant recipients using a prednisone-free regimen with over 8.5 years of follow-up. Patients received methylprednisonlone and anti-IL2 receptor antagonist (Basiliximab) induction and were blindly randomized to either the tacrolimus/mycophenolate mofetil (n=45) or tacrolimus/sirolimus (n=37) groups. Outcome measures included patient and renal allograft survival, incidence of acute rejection, and estimated GFR.

RESULTS

The tacrolimus/mycophenolate mofetil group compared with the tacrolimus/sirolimus group had overall better renal allograft survival (91% versus 70%, P=0.02); 13 patients (35.1%) in the tacrolimus/sirolimus group and 8 patients (17.8%) in the tacrolimus/mycophenolate mofetil group experienced biopsy-proven acute cellular rejection (P=0.07). By 3 months post-transplant, estimated GFR was significantly lower in the tacrolimus/sirolimus group compared with the tacrolimus/mycophenolate mofetil group (47.7 versus 59.6 ml/min per 1.73 m(2), P=0.0002), and this trend persisted throughout the follow-up period. Also, the slope of decline in the tacrolimus/sirolimus group was significantly steeper than in the tacrolimus/mycophenolate mofetil group.

CONCLUSIONS

This study shows that, in a prednisone-free immunosuppressive regimen, long-term renal graft survival and function are significantly worse in the tacrolimus/sirolimus group than the tacrolimus/mycophenolate mofetil group. The synergistic nephrotoxic effect and higher acute rejection rates in the tacrolimus/sirolimus compared with the tacrolimus/mycophenolate mofetil group adversely affect graft survival.

A comprehensive risk assessment of mortality following donation after cardiac death liver transplant - an analysis of the national registry

BACKGROUND & AIMS

Organ scarcity has resulted in increased utilization of donation after cardiac death (DCD) donors. Prior analysis of patient survival following DCD liver transplantation has been restricted to single institution cohorts and a limited national experience. We compared the current national experience with DCD and DBD livers to better understand survival after transplantation.

METHODS

We compared 1113 DCD and 42,254 DBD recipients from the Scientific Registry of Transplant Recipients database between 1996 and 2007. Patient survival was analyzed using the Kaplan-Meier methodology and Cox regression.

RESULTS

DCD recipients experienced worse patient survival compared to DBD recipients (p<0.001). One and 3 year survival was 82% and 71% for DCD compared to 86% and 77% for DBD recipients. Moreover, DCD recipients required re-transplantation more frequently (DCD 14.7% vs. DBD 6.8%, p<0.001), and re-transplantation survival was markedly inferior to survival after primary transplant irrespective of graft type. Amplification of mortality risk was observed when DCD was combined with cold ischemia time >12h (HR = 1.81), shared organs (HR = 1.69), recipient hepatocellular carcinoma (HR=1.80), recipient age >60 years (HR = 1.92), and recipient renal insufficiency (HR = 1.82).

CONCLUSIONS

DCD recipients experience significantly worse patient survival after transplantation. This increased risk of mortality is comparable in magnitude to, but often exacerbated by other well-established risk predictors. Utilization decisions should carefully consider DCD graft risks in combination with these other factors.

Coronary multidetector computed tomographic angiography to evaluate coronary artery disease in liver transplant candidates: methods, feasibility and initial experience

AIMS

In patients undergoing orthotopic liver transplantation (OLT), coronary artery disease (CAD), obstructive and nonobstructive, is associated with high morbidity and mortality. In OLT candidates, stress testing for detecting ischemia is often inaccurate, and this patient population often has relative contraindications for cardiac catheterization. The objective of this study was to describe the methods, assess the feasibility and determine the extent and severity of CAD in OLT candidates without a prior history of CAD using coronary multidetector computer tomographic angiography (MDCTA).

METHODS

Sixty-five OLT candidates without known CAD underwent coronary MDCTA with dual source cardiac computed tomography (Siemens Definition). Coronary arteries were divided into 17 segments based on American Heart Association guidelines and evaluated independently by two blinded reviewers. Image quality of coronary MDCTA was assessed on a four-point Likert scale (0 = poor, 1 = fair, 2 = good, and 3 = excellent). Atherosclerotic lesions were evaluated for severity [mild (0-50%), moderate (51-70%), and severe (71-100%)], morphology, extent, location and consistency.

RESULTS

Image quality was graded as good or excellent in 73.8%. In this cohort of OLT candidates without known CAD, 9% had normal coronary arteries, 58% had mild CAD and 34% had moderate to severe CAD. Plaque severity and burden scores were high.

CONCLUSION

The prevalence of asymptomatic CAD is high in OLT candidates. Coronary MDCTA is feasible in OLT candidates and appears to be a useful technique to diagnose occult CAD in this patient population.

Cardiovascular risk assessment of the liver transplant candidate

Liver transplantation (LT) candidates today are increasingly older, have greater medical acuity, and have more cardiovascular comorbidities than ever before. Steadily rising model for end-stage liver disease (MELD) scores at the time of transplant, resulting from high organ demand, reflect the escalating risk profiles of LT candidates. In addition to advanced age and the presence of comorbidities, there are specific cardiovascular responses in cirrhosis that can be detrimental to the LT candidate. Patients with cirrhosis requiring LT usually demonstrate increased cardiac output and a compromised ventricular response to stress, a condition termed cirrhotic cardiomyopathy. These cardiac disturbances are likely mediated by decreased beta-agonist transduction, increased circulating inflammatory mediators with cardiodepressant properties, and repolarization changes. Low systemic vascular resistance and bradycardia are also commonly seen in cirrhosis and can be aggravated by beta-blocker use. These physiologic changes all contribute to the potential for cardiovascular complications, particularly with the altered hemodynamic stresses that LT patients face in the immediate post-operative period. Post-transplant reperfusion may result in cardiac death due to a multitude of causes, including arrhythmia, acute heart failure, and myocardial infarction. Recognizing the hemodynamic challenges encountered by LT patients in the perioperative period and how these responses can be exacerbated by underlying cardiac pathology is critical in developing recommendations for the pre-operative risk assessment and management of these patients. The following provides a review of the cardiovascular challenges in LT candidates, as well as evidence-based recommendations for their evaluation and management.

A review of quality of life instruments used in liver transplantation

With improvements in patient and graft survival after liver transplantation, recipient quality of life (QOL) has become an important focus of patient care and clinical outcomes research. To provide a better understanding of the instruments used to assess QOL in the adult liver transplant population, we conducted a systematic review of the MEDLINE database and Cochrane library. Our review identified 128 relevant articles utilizing more than 50 different QOL instruments. Generic health status instruments are the most commonly used, and among them the Medical Outcomes Study Short Form-36 (SF-36), the Hospital Anxiety and Depression Scale (HADS), and the Beck Depression Inventory (BDI) are the most prevalent. Few studies (16%) included targeted, disease-specific instruments. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Quality of Life questionnaire, the Liver Disease Quality of Life questionnaire, and the Chronic Liver Disease questionnaire are the most frequently employed targeted instruments; however, these instruments have been designed to assess QOL in patients with chronic liver disease rather than patients after liver transplantation. The present review focuses on the psychometric properties of the existing QOL instruments and discusses their individual strengths and limitations in evaluating liver transplantation recipients. The lack of a gold-standard QOL instrument for liver transplant recipients is an impediment to cross-study comparisons. We conclude that the development of a QOL instrument specifically for liver transplant recipients will improve QOL assessment in this population leading to a more nuanced understanding of the factors that influence transplant recipients' well-being.

The impact of ischemic cholangiopathy in liver transplantation using donors after cardiac death: the untold story

BACKGROUND

Liver transplantation (LT) from donation after cardiac death (DCD) donors is increasingly being used to address organ shortages. Despite encouraging reports, standard survival metrics have overestimated the effectiveness of DCD livers. We examined the mode, kinetics, and predictors of organ failure and resource utilization to more fully characterize outcomes after DCD LT.

METHODS

We reviewed the outcomes for 32 DCD and 237 donation after brain death (DBD) LT recipients at our institution.

RESULTS

Recipients of DCD livers had a 2.1 times greater risk of graft failure, a 2.5 times greater risk of relisting, and a 3.2 times greater risk of retransplantation compared with DBD recipients. DCD recipients had a 31.6% higher incidence of biliary complications and a 35.8% higher incidence of ischemic cholangiopathy. Ischemic cholangiography was primarily implicated in the higher risk of graft failure observed after DCD LT. DCD recipients with ischemic cholangiography experienced more frequent rehospitalizations, longer hospital stays, and required more invasive biliary procedures.

CONCLUSION

Related to higher complication rates, DCD recipients necessitated greater resource utilization. This more granular data should be considered in the decision to promote DCD LT. Modification of liver allocation policy is necessary to address those disadvantaged by a failing DCD graft.

Impact of anemia after renal transplantation on patient and graft survival and on rate of acute rejection

BACKGROUND AND OBJECTIVES

The impact of posttransplantation anemia on patient survival, renal allograft survival, and rate of acute rejection is not known.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A total of 1023 patients who underwent kidney transplantation at one center from January 1992 through June 2003 were retrospectively analyzed. Posttransplantation anemia was defined as mean hemoglobin <11 g/dl after 3 mo after transplantation. Data on demographics, pretransplantation dialysis, previous transplant history, pretransplantation hemoglobin, degree of HLA mismatch, and donor characteristics were collected. Some of the posttransplantation data that were collected in addition to the hemoglobin included delayed graft function; diabetes; hypertension; induction and maintenance of immunosuppressive regimen; posttransplantation infections; and use of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, statins, aspirin, and beta blockers. Cox regression models were used to assess the effects of posttransplantation anemia on each outcome: Mortality, graft survival, and rate of acute rejection. Median follow-up time was 4 yr.

RESULTS

During the entire follow-up period, there were 89 (9%) deaths, 143 (14%) acute rejection episodes, and 235 (23%) kidney losses. In multivariate Cox regression models, being anemic after transplantation, after the first 90 d, was associated with increased overall mortality and increased renal allograft loss. Posttransplantation anemia was also associated with increased acute rejection rates.

CONCLUSIONS

This study shows that posttransplantation anemia is associated with worse patient and graft survival and higher rates of acute rejection when compared with nonanemic renal transplant recipients.

Impairment of recipient cytolytic activity attenuates allograft vasculopathy

We investigated the role of CD4+ and CD8+ T subsets as well as T cell cytolytic effector mechanisms in the aortic allograft model of allograft vasculopathy using CD4 and CD8 gene knockout mice (CD4(-/-), CD8(-/-)) and mice deficient in cytolytic effector pathways. Medial apoptosis at 2 weeks was reduced in CD8(-/-) mice and in mice where cytotoxic T cell activity was compromised. At 8 weeks, substantial medial damage was observed in wild-type (WT) and CD4(-/-) recipients but medial preservation was evident in CD8(-/-) mice and in mice with impaired cytotoxic T cell activity. The intima/media ratio, a comprehensive measure of allograft vasculopathy, was similar in WT and CD4(-/-) recipients but was significantly reduced in CD8(-/-) mice and mice with impaired cytotoxic T cell activity. These data indicate that CD8+ T cells contribute to the vascular remodeling that is characteristic of allograft vasculopathy. They also show that CD8+ T cells participate in allograft vasculopathy in the absence of CD4+ T cell help. We further demonstrated that WT mice exhibited robust allograft vasculopathy in the presence of cyclosporin A immunosuppression but that allograft vasculopathy was ablated in cyclosporin-treated CD8(-/-) mice. This supports the hypothesis that non-CD8+ T cell effector mechanisms are sensitive to calcineurin inhibitor therapy but that CD8+ T cell-mediated allograft vasculopathy is refractory to such treatment. Taken together, our data suggest that CD8+ T cells contribute to the induction of vascular remodeling in allograft vasculopathy and provide evidence that novel therapies which target CD8+ T cell effector function might be effective in mitigating AV in the clinical setting.

CD8 T cells mediate aortic allograft vasculopathy by direct killing and an interferon-?-dependent indirect pathway

OBJECTIVE

Allograft vasculopathy (AV) has emerged as the major obstacle to long-term survival in clinical heart transplantation. Immune events are implicated in the development of AV, but the cellular and molecular mechanisms involved remain unclear. We sought to determine whether and by what mechanism CD8(+) T lymphocytes are able to generate AV in a murine aortic allograft model.

METHODS

Allo-primed CD8(+) T lymphocytes were transferred into immunodeficient (RAG-1(-/-)) mouse recipients of aortic allografts. We also transferred primed CD8(+) T cells with targeted deletions of effector molecules (perforin, Fas-ligand) to determine the role of direct cytolysis (CTL) in CD8(+) T-cell-mediated AV. We determined the role of non-CTL effector mechanisms through the transfer of either wildtype or interferon-gamma (IFN-gamma)-deficient CD8(+) T cells into RAG-1(-/-) recipients of MHC class I-deficient allografts.

RESULTS

Adoptive transfer of primed wildtype CD8(+) T lymphocytes into immunodeficient recipients of aortic allografts resulted in the development of robust AV lesions. Transfer of CD8(+) T lymphocytes with targeted deletions in CTL effector molecules resulted in reduction of AV lesion size but not abrogation. Transfer of wildtype CD8(+) T cells into recipients of MHC class I-deficient grafts resulted in a reduction in AV lesion size, while transfer of interferon-gamma-deficient CD8(+) T cells into MHC class I-deficient grafts abrogated AV.

CONCLUSIONS

These data indicate that CD8(+) T cells mediate AV through direct cytolysis and a distinct interferon-gamma-dependent non-CTL effector pathway. Given the resistance of this cell type to conventional immunosuppression, these results may have important therapeutic implications.