Association Between Sarcopenia and Functional Status in Liver Transplant Patients.

OBJECTIVES: A growing body of evidence shows that frailty and functional performance predict liver transplant outcomes. The Organ Procurement and Transplant Network uses the Karnofsky Performance Status scale to adjust for transplant center case mix in assessing quality measures. This study explores the strength of the relationship between Karnofsky Performance Status scores and objective measures of frailty. MATERIALS AND METHODS: This observational study includes 136 adult, first-time liver transplant recipients at UMass Memorial (2006-2015) who had 2 abdominal computed tomography scans available (at ≤ 90 days pretransplant and ≥ 7 days before that). We analyzed the relationship between Karnofsky Performance Status and muscle wasting using absolute and change in psoas muscle size and quality pretransplant. RESULTS: The mean age was 55 years, mean Model for End-Stage Liver Disease was 22, and 34% of patients were women. In the study group, 50% of patients had sarcopenia pretransplant and 71.3% demonstrated declined lean psoas area at an average rate of 11% per month. Patients who experienced muscle wasting at a rate of ≥ 1% per month had 2.83 times the risk (95% confidence interval, 1.18-6.80) of being severely impaired/disabled pretransplant. The risk increased by 2.32-fold (95% confidence interval, 1.44-3.75) for every standard deviation decrease in pretransplant lean psoas area. CONCLUSIONS: Provider-assessed physical health status moderately correlates with objective measures of frailty.

Donor Diabetes and Prolonged Cold Ischemia Time Synergistically Increase the Risk of Graft Failure After Liver Transplantation.

BACKGROUND: Both prolonged cold ischemia time (CIT) and donor history of diabetes mellitus (DM) are associated with reduced graft survival after liver transplantation. However, it is unknown whether the adverse effect of prolonged CIT on posttransplant graft survival is more pronounced after transplant with DM versus non-DM donor grafts. METHODS: The study sample included 58 226 liver transplant recipients (2002-2015) from the Scientific Registry of Transplant Recipients. Multivariable Cox survival regression with interaction analysis was used to quantify the extent to which history of donor DM (n = 6478) potentiates the adverse effect of prolonged (≥8 hours) CIT (n = 18 287) on graft survival. RESULTS: Donor DM and CIT 8 hours or longer were each associated with increased risk of graft failure (GF) (adjusted hazard ratio [aHR], 1.19; 95% confidence interval [CI], 1.06-1.35 and aHR, 1.42; 95% CI, 1.32-1.53, respectively) compared with transplanted grafts without either risk factor. However, the combination of DM and CIT 8 hours or longer was associated with a higher risk of GF than either factor alone (aHR, 1.79; 95% CI, 1.55-2.06) and had a synergy index of 1.30. The interaction was significant on a multiplicative scale in the later postoperative period, days 31 to 365 (P = 0.047). CONCLUSIONS: These results suggest that liver grafts from DM donors are more susceptible to the adverse effects of prolonged CIT than livers from non-DM donors. We need to be cognizant that they are more susceptible to ischemic injury, and this may be considered during the allocation process.

Functional status predicts postoperative mortality after liver transplantation.

BACKGROUND: Frail patients are more vulnerable to perioperative stressors of liver transplantation (LT). Program Specific Reports, used in transplant center auditing, risk-adjust for frailty using the Karnofsky Performance Status (KPS) scale. We evaluate the extent to which functional impairment/disability is associated with increased risk of postoperative death. METHODS: We included 24 505 first-time LT recipients from the Scientific Registry of Transplant Recipients (2006-2011). We categorized patients as Severe, Moderate, or Normal function/disability using the KPS scale and evaluated risk of 30- and 90-day mortality. Analyses took potential center-specific differences in KPS measurement protocols into account using hierarchal logistic modeling. RESULTS: Over one-quarter of our population was Severely impaired/disabled, and 30.5% had no functional limitations. Severely and Moderately impaired/disabled patients had 2.56 (95% CI 1.91-3.44) and 1.40 (95% CI 1.10-1.78) times the odds of 30-day mortality, respectively, after adjusting for key recipient and donor factors. Estimates remained consistent regardless of Model for End-Stage Liver Disease score, medical condition, or clustering analyses by center. Technical/operative complications and multiorgan failure/hemorrhage were more common causes of death among more Severely disabled patients than in higher functioning groups. CONCLUSIONS: Pre-transplant functional status, assessed using the KPS scale, is a reliable predictor of post-LT mortality in the United States.

Decade-Long Trends in Liver Transplant Waitlist Removal Due to Illness Severity: The Impact of Centers for Medicare and Medicaid Services Policy.

BACKGROUND: The central tenet of liver transplant organ allocation is to prioritize the sickest patients first. However, a 2007 Centers for Medicare and Medicaid Services regulatory policy, Conditions of Participation (COP), which mandates publically reported transplant center performance assessment and outcomes-based auditing, critically altered waitlist management and clinical decision making. We examine the extent to which COP implementation is associated with increased removal of the "sickest" patients from the liver transplant waitlist. STUDY DESIGN: This study included 90,765 adult (aged 18 years and older) deceased donor liver transplant candidates listed at 102 transplant centers from April 2002 through December 2012 (Scientific Registry of Transplant Recipients). We quantified the effect of COP implementation on trends in waitlist removal due to illness severity and 1-year post-transplant mortality using interrupted time series segmented Poisson regression analysis. RESULTS: We observed increasing trends in delisting due to illness severity in the setting of comparable demographic and clinical characteristics. Delisting abruptly increased by 16% at the time of COP implementation, and likelihood of being delisted continued to increase by 3% per quarter thereafter, without attenuation (p < 0.001). Results remained consistent after stratifying on key variables (ie, Model for End-Stage Liver Disease and age). The COP did not significantly impact 1-year post-transplant mortality (p = 0.38). CONCLUSIONS: Although the 2007 Centers for Medicare and Medicaid Services COP policy was a quality initiative designed to improve patient outcomes, in reality, it failed to show beneficial effects in the liver transplant population. Patients who could potentially benefit from transplantation are increasingly being denied this lifesaving procedure while transplant mortality rates remain unaffected. Policy makers and clinicians should strive to balance candidate and recipient needs from a population-benefit perspective when designing performance metrics and during clinical decision making for patients on the waitlist.

Rodent models of partial hepatectomies.

Small rodents are the most used experimental models in liver surgical research. Hepatic resections in rodents are commonly performed to study liver regeneration, acute liver failure, hepatic metastasis, hepatic function, 'small-for-size' transplantation and metabolic response to injury. Most resections require only basic skills, are fast, reliable and highly reproducible. The partial hepatectomy technique in rodents can be improved by microsurgical techniques, which permit individualized dissection and ligature of the vascular and biliary branches with minimal operative morbidity and mortality. This is particularly relevant for murine models of liver resection. However, it requires advanced microsurgical skills. Here, we review the models, surgical techniques, results and limitations of partial liver resections in rodent models. We also reported for the first time segmentectomies of the median lobe in rodent models.

Heme oxygenase-1 ameliorates ischemia/reperfusion injury by targeting dendritic cell maturation and migration.

Ischemia/reperfusion injury (IRI) has a major impact on short- and long-term renal allograft survival by increasing graft immunogenicity. Donor preconditioning by inducing heme oxygenase 1 (HO-1) has been proven to exert cytoprotective and antiinflammatory effects on the graft, thus resulting in reduced graft immunogenicity. The study analyzed the effects and mechanisms of HO-1-mediated cytoprotection in rat kidney transplants exposed to cold preservation. We studied the differential gene-expression patterns of allografts after either short or long cold ischemia using a customized cDNA microarray. Prolonged cold ischemia led, 12 h after engraftment, to enhanced levels of adhesion molecules, heat-shock proteins, chemokines (CXCL10), and a remarkable upregulation of immunoproteasomes. Next we addressed the question whether induction of HO-1 or its byproduct carbon monoxide (CO) in organ donors targets these candidate markers related to enhanced immunogenicity. Induction of HO-1 or CO in organ donors 24 h before organ harvesting resulted in reduced mRNA levels of immunoproteasomes, MHC class II expression, and co-stimulatory molecules in the recipient's spleen, suggesting diminished migration and activation of donor dendritic cells. This observation suggests that HO-1/CO induction protects marginal allografts by inhibiting the immunogenicity of donor-derived dendritic cells.

Modifying graft immunogenicity and immune response prior to transplantation: potential clinical applications of donor and graft treatment.

Many studies have shown a strong association between initial graft injury and poor long-term graft outcome. Events initiated by unspecific immune-activating processes including brain death and ischemia/reperfusion injury occurring prior to transplantation reduce graft functionality and amplify the host immune response. These events may be particularly relevant for less than optimal grafts with reduced resistance to unspecific injuries. Several approaches to ameliorate immune activation of the graft by treating the donor or the graft have been studied. While various substances have been shown to have protective effects in experimental transplantation, only a few drugs have been tested clinically and have demonstrated beneficial effects. We review the results of experimental and clinical studies on donor or graft immunomodulation prior to transplantation and analyze the evidence to support clinical application of these strategies.

Age and immune response in organ transplantation.

The immune system undergoes a complex and continuous remodeling as the result of aging. These changes have a major impact on allorecognition and alloresponse. In addition, immunosuppression in the elderly is challenging as a consequence of an increased incidence of associated comorbidities and altered pharmacokinetics. Both advanced donor and recipient age should be considered independent risk factors for poor patient and graft survival rates, albeit acting in a synergistic manner. Consequently, modifications of the immune system because of aging may request an age-adapted allocation and immunosuppression in parallel with close patient monitoring. Interventions to selectively target changes associated with the senescence process seem to be promising therapeutic strategies to improve transplantation outcome. Here, we are going to review the immunologic changes associated with the aging process relevant for transplantation and their impact on immunosuppressive protocols, organ allocation policies, and transplantation outcome.