Hypothermic machine perfusion in liver transplantation.

Dynamic preservation strategies are a promising option to improve graft quality before transplantation, and to extend preservation time for either logistic or treatment reasons. In contrast to normothermic oxygenated perfusion, which intends to mimic physiological conditions in the human body, with subsequent clinical application for up to 24 hrs, hypothermic perfusion is mainly used for a relatively short period with protection of mitochondria and subsequent reduction of oxidative injury upon implantation. The results from two randomized controlled trials, where recruitment has finished are expected this year. Both ex situ perfusion techniques are increasingly applied in clinical transplantation including recent reports on viability assessment, which could open the door for an increased liver utilization in the future.

No country for old livers? Examining and optimizing the utilization of elderly liver grafts.

Of the 1.6 million patients >70 years of age who died of stroke since 2002, donor livers were retrieved from only 2402 (0.15% yield rate). Despite reports of successful liver transplantation (LT) with elderly grafts (EG), advanced donor age is considered a risk for poor outcomes. Centers for Medicare and Medicaid Services definitions of an "eligible death" for donation excludes patients >70 years of age, creating disincentives to donation. We investigated utilization and outcomes of recipients of donors >70 through analysis of a United Network for Organ Sharing Standard Transplant Analysis and Research-file of adult LTs from 2002 to 2014. Survival analysis was conducted using Kaplan-Meier curves, and Cox regression was used to identify factors influencing outcomes of EG recipients. Three thousand one hundred four livers from donors >70, ≈40% of which were used in 2 regions: 2 (520/3104) and 9 (666/3104). Unadjusted survival was significantly worse among recipients of EG compared to recipients of younger grafts (P < .0001). Eight independent negative predictors of survival in recipients of EG were identified on multivariable analysis. Survival of low-risk recipients who received EG was significantly better than survival of recipients of younger grafts (P = .04). Outcomes of recipients of EG can therefore be optimized to equal outcomes of younger grafts. Given the large number of stroke deaths in patients >70 years of age, the yield rate of EGs can be maximized and disincentives removed to help resolve the organ shortage crisis.

Machine Perfusion of Donor Livers for Transplantation: A Proposal for Standardized Nomenclature and Reporting Guidelines.

With increasing demand for donor organs for transplantation, machine perfusion (MP) promises to be a beneficial alternative preservation method for donor livers, particularly those considered to be of suboptimal quality, also known as extended criteria donor livers. Over the last decade, numerous studies researching MP of donor livers have been published and incredible advances have been made in both experimental and clinical research in this area. With numerous research groups working on MP, various techniques are being explored, often applying different nomenclature. The objective of this review is to catalog the differences observed in the nomenclature used in the current literature to denote various MP techniques and the manner in which methodology is reported. From this analysis, we propose a standardization of nomenclature on liver MP to maximize consistency and to enable reliable comparison and meta-analyses of studies. In addition, we propose a standardized set of guidelines for reporting the methodology of future studies on liver MP that will facilitate comparison as well as clinical implementation of liver MP procedures.

Hypothermic machine preservation facilitates successful transplantation of "orphan" extended criteria donor livers.

Hypothermic machine preservation (HMP) remains investigational in clinical liver transplantation. It is widely used to preserve kidneys for transplantation with improved results over static cold storage (SCS). At our center, we have used HMP in 31 adults receiving extended criteria donor (ECD) livers declined by the originating United Network for Organ Sharing region ("orphan livers"). These cases were compared to ECD SCS cases in a matched cohort study design. Livers were matched for donor age, recipient age, cold ischemic time, donor risk index and Model for End-Stage Liver Disease (MELD) score. HMP was performed for 3-7 h at 4-8 °C using our previously published protocol. Early allograft dysfunction rates were 19% in the HMP group versus 30% in the control group (p = 0.384). One-year patient survival was 84% in the HMP group versus 80% in the SCS group (p = NS). Post hoc analysis revealed significantly less biliary complications in the HMP group versus the SCS group (4 vs. 13, p = 0.016). Mean hospital stay was significantly shorter in the HMP group (13.64 ± 10.9 vs. 20.14 ± 11.12 days in the SCS group, p = 0.001). HMP provided safe and reliable preservation in orphan livers transplanted at our center.

The benefits of hypothermic machine perfusion are enhanced with Vasosol and α-tocopherol in rodent donation after cardiac death livers.

The use of hypothermic machine perfusion (HMP) has recently been used to show an improvement in both standard and extended criteria donor liver grafts but creating a more dynamic preservation environment that can be supplemented with a variety of additives to aid in cold temperature metabolism and vasodilatation. Increasing the benefits of HMP, we explore the use of α-tocopherol in reducing inflammatory markers and apoptotic pathways to reduce the incidence of preservation injury. We explored the use of a donation after cardiac death (DCD) rodent model to test the additive benefits of α-tocopherol in HMP. The addition of α-tocopherol reduced the level of alanine aminotransferase (ALT) over the course of reperfusion as well, reduced the levels of inflammatory cytokines within a 90 minute reperfusion biopsy. Further benefit was seen with α-tocopherol through the reduction of the level of caspase 3/7 in the circulation, shown to be a result of the reduction of the levels of Cytochrome C mRNA. Liver perfusion with Vasosol® and HMP could benefit further from the addition of α-tocopherol to existing formulations of Vasosol®.

Totally laparoscopic full left hepatectomy for living donor liver transplantation in adolescents and adults.

In recent years different minimal access strategies have been designed in order to perform living donor liver surgery for adult recipients with less morbidity. Techniques involve shortening the length of the incision with or without previous laparoscopic mobilization of the liver. Herein we present two cases of totally laparoscopic living donor left hepatectomy, with and without removal of the middle hepatic vein, respectively. We describe in detail the anatomical and technical aspects of the procedure focusing on relevant points to enhance safety.

Liver defatting: an alternative approach to enable steatotic liver transplantation.

Macrovesicular steatosis in greater than 30% of hepatocytes is a significant risk factor for primary graft nonfunction due to increased sensitivity to ischemia reperfusion (I/R) injury. The growing prevalence of hepatic steatosis due to the obesity epidemic, in conjunction with an aging population, may negatively impact the availability of suitable deceased liver donors. Some have suggested that metabolic interventions could decrease the fat content of liver grafts prior to transplantation. This concept has been successfully tested through nutritional supplementation in a few living donors. Utilization of deceased donor livers, however, requires defatting of explanted organs. Animal studies suggest that this can be accomplished by ex vivo warm perfusion in a time scale of a few hours. We estimate that this approach could significantly boost the size of the donor pool by increasing the utilization of steatotic livers. Here we review current knowledge on the mechanisms whereby excessive lipid storage and macrosteatosis exacerbate hepatic I/R injury, and possible approaches to address this problem, including ex vivo perfusion methods as well as metabolically induced defatting. We also discuss the challenges ahead that need to be addressed for clinical implementation.

Protein C activity and postoperative metabolic liver function after liver transplantation.

BACKGROUND: Protein C is a natural thrombin antagonist produced by hepatocytes. Its levels are low in liver failure and predispose patients to increased risk for thrombosis. Little is known about the relationship between protein C activity and hepatic function after orthotopic liver transplantation (OLT). METHODS: We measured protein C activity of 41 patients undergoing liver transplantation by the Staclot method (normal range, 70%-130%) preoperatively and then daily on postoperative days (POD) 0-5. RESULTS: The mean protein C activity was low before OLT (34.3 ± 4.3%) and inversely correlated with the preoperative Model for End-Stage Liver Disease score (Spearman's r = -0.643; P < .0001). Mean activity increased significantly on POD 1 (58.9 ± 4.5%), and remained above preoperative levels through POD 5. Ten patients developed metabolic liver dysfunction defined by a serum total bilirubin >5 mg/dL on POD 7. These patients had significantly lower protein C activity from POD 3 (47.2 ± 9.6% vs 75.9 ± 5.8%; P = .01) to POD 5. Preoperative protein C activity correlated inversely with the severity of liver failure as indicated by preoperative MELD score. CONCLUSION: Protein C activity recovered rapidly in patients with good allograft function but remained significantly lower in patients who had limited metabolic function as evidenced by increased total bilirubin levels.

Hypothermic machine preservation reduces molecular markers of ischemia/reperfusion injury in human liver transplantation.

Hypothermic machine perfusion (HMP) is in its infancy in clinical liver transplantation. Potential benefits include diminished preservation injury (PI) and improved graft function. Molecular data to date has been limited to extrapolation of animal studies. We analyzed liver tissue and serum collected during our Phase 1 trial of liver HMP. Grafts preserved with HMP were compared to static cold stored (SCS) transplant controls. Reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry and transmission electron microscopy (TEM) were performed on liver biopsies. Expression of inflammatory cytokines, adhesion molecules and chemokines, oxidation markers, apoptosis and acute phase proteins and the levels of CD68 positive macrophages in tissue sections were evaluated. RT-PCR of reperfusion biopsy samples in the SCS group showed high expression of inflammatory cytokines, adhesion molecules and chemokines, oxidative markers and acute phase proteins. This upregulation was significantly attenuated in livers that were preserved by HMP. Immunofluorescence showed larger numbers of CD68 positive macrophages in the SCS group when compared to the HMP group. TEM samples also revealed ultrastructural damage in the SCS group that was not seen in the HMP group. HMP significantly reduced proinflammatory cytokine expression, relieving the downstream activation of adhesion molecules and migration of leukocytes, including neutrophils and macrophages when compared to SCS controls.

The deceased organ donor with an "open abdomen": proceed with caution.

In solid organ transplantation, the disparity between donor supply and patients awaiting transplant continues to increase. The organ shortage has led to relaxation of historic contraindications to organ donation. A large percentage of deceased organ donors have been subjected to traumatic injuries, which can often result in intervention that leads to abdominal packing and intensive care unit resuscitation. The donor with this "open abdomen" (OA) presents a situation in which the risk of organ utilization is difficult to quantify. There exists a concern for the potential of a higher risk for both bacterial and fungal infections, including multidrug-resistant (MDR) pathogens because of the prevalence of antibiotic use and critical illness in this population. No recommendations have been established for utilization of organs from these OA donors, because data are limited. Herein, we report a case of a 21-year-old donor who had sustained a gunshot wound to his abdomen, resulting in a damage-control laparotomy and abdominal packing. The donor subsequently suffered brain death, and the family consented to organ donation. A multiorgan procurement was performed with respective transplantation of the procured organs (heart, liver, and both kidneys) into 4 separate recipients. Peritoneal swab cultures performed at the time of organ recovery grew out MDR Pseudomonas aeruginosa on the day after procurement, subsequently followed by positive blood and sputum cultures as well. All 4 transplant recipients subsequently developed infections with MDR P. aeruginosa, which appeared to be donor-derived with similar resistance patterns. Appropriate antibiotic coverage was initiated in all of the patients. Although 2 of the recipients died, mortality did not appear to be clearly associated with the donor-derived infections. This case illustrates the potential infectious risk associated with organs from donors with an OA, and suggests that aggressive surveillance for occult infections should be pursued.

Hypothermic machine preservation in human liver transplantation: the first clinical series.

Hypothermic machine perfusion (HMP) is widely used to preserve kidneys for transplantation with improved results over cold storage (CS). To date, successful transplantation of livers preserved with HMP has been reported only in animal models. In this, the first prospective liver HMP study, 20 adults received HMP-preserved livers and were compared to a matched group transplanted with CS livers. HMP was performed for 3-7 h using centrifugal perfusion with Vasosol solution at 4-6 degrees C. There were no cases of primary nonfunction in either group. Early allograft dysfunction rates were 5% in the HMP group versus 25% in controls (p = 0.08). At 12 months, there were two deaths in each group, all unrelated to preservation or graft function. There were no vascular complications in HMP livers. Two biliary complications were observed in HMP livers compared with four in the CS group. Serum injury markers were significantly lower in the HMP group. Mean hospital stay was shorter in the HMP group (10.9 +/- 4.7 days vs. 15.3 +/- 4.9 days in the CS group, p = 0.006). HMP of donor livers provided safe and reliable preservation in this pilot case-controlled series. Further multicenter HMP trials are now warranted.

Survival outcomes following liver transplantation (SOFT) score: a novel method to predict patient survival following liver transplantation.

It is critical to balance waitlist mortality against posttransplant mortality. Our objective was to devise a scoring system that predicts recipient survival at 3 months following liver transplantation to complement MELD-predicted waitlist mortality. Univariate and multivariate analysis on 21,673 liver transplant recipients identified independent recipient and donor risk factors for posttransplant mortality. A retrospective analysis conducted on 30,321 waitlisted candidates reevaluated the predictive ability of the Model for End-Stage Liver Disease (MELD) score. We identified 13 recipient factors, 4 donor factors and 2 operative factors (warm and cold ischemia) as significant predictors of recipient mortality following liver transplantation at 3 months. The Survival Outcomes Following Liver Transplant (SOFT) Score utilized 18 risk factors (excluding warm ischemia) to successfully predict 3-month recipient survival following liver transplantation. This analysis represents a study of waitlisted candidates and transplant recipients of liver allografts after the MELD score was implemented. Unlike MELD, the SOFT score can accurately predict 3-month survival following liver transplantation. The most significant risk factors were previous transplantation and life support pretransplant. The SOFT score can help clinicians determine in real time which candidates should be transplanted with which allografts. Combined with MELD, SOFT can better quantify survival benefit for individual transplant procedures.

Microscopic intrarenal particles after pulsatile machine preservation do not adversely affect outcomes after renal transplantation.

INTRODUCTION: Our center has recently observed foreign carbohydrate-appearing particles (FP) on transplant postreperfusion biopsy specimens: (PRBx). METHODS: To further characterize FPs, we reviewed all renal transplant RBx (30-45 minutes) performed between September 1, 2004 and December 3, 2005. Donor, preservation, and outcome variables were collected among patients with FP. RESULTS: A total of 135 PRBx were performed (45 deceased donors [DD] and 90 live donors [LD]). Fifteen PRBx demonstrated FP. All 15 cases were DD kidneys that underwent machine perfusion (MP) on the Waters RM3 (Waters Medical Systems, Rochester, Minn, United States) with Belzer MP solution (Trans Med, Elk River, Minn, United States). Donor age was 39.8 +/- 15.7 years. Terminal creatinine level was 1.45 +/- 0.8 mg/dL. Two of 15 were flushed in situ with HTK solution (no starch). Cold ischemia time was 28.8 +/- 9.1 hours with 14.3 +/- 5.1 hours of MP. In 13 of 15 patients, perfusion parameters were excellent (flow > 100 mL; resistance < .35). CHARACTERISTICS OF FP: Particles were 10-30 mu and globular in shape. FP were not visible on hematoxylin and eosin stain, but stained strongly periodic acid-Schiff-(PAS) positive and were refractile under polarized light. FP were seen segmentally within glomerular capillaries in all cases and in peritubular capillaries in 3. In 11 of the 15 cases with FP, focal glomerular fibrin thrombi or intracapillary neutrophil margination was seen. Ten of 15 patients with FP had a biopsy within the first week with no identifiable FP. OUTCOMES: Recipient age was 45.3 +/- 11.6 years. Eight patients (53.3%) had delayed graft function. Biopsy-proven rejection occurred in 3 patients (20%). Three-month creatinine level was 1.59 +/- 0.35 mg/dL. One graft was lost to early thrombosis in a patient with a hypercoagulable state and 1 patient died of sepsis at 2 months. All remaining 13 patients are alive with excellent graft function at a median follow-up of 6.7 months (range, 3-17 months). CONCLUSIONS: Microscopic intrarenal particles may be seen on DD kidney PRBx after MP. These FPs likely originate from surgical gloves. FPs are too small to be captured by standard filters but clear spontaneously and do not have deleterious effects on renal function or outcomes.

Hypothermic machine perfusion of liver grafts for transplantation: technical development in human discard and miniature swine models.

INTRODUCTION: Cold storage (CS) is the standard preservation technique for liver transplantation (LTx). Hypothermic machine perfusion (HMP) is an alternative preservation technique that provides a continuous supply of substrates and removes waste products. HMP improves early graft function in kidney transplantation, especially for marginal organs: To our knowledge there have been no reports HMP in human LTx. The aim of this study was to develop a reproducible technique for liver HMP prior to initiating a clinical trial. METHODS: For the discard protocol, between May 2001 and March 2002, 10 nontransplantable human livers were obtained. We designed a model of atraumatic, centrifugal HMP of the portal vein (PV) and hepatic artery (HA) via donor vascular conduit. Livers were perfused at 3 degrees C to 5 degrees C with Vasosol solution for 5 to 10 hours using a modified Medtronic Portable Bypass System. Perfusion variables (temp, flow, pressure) where recorded every 30 minutes. During the study, we also validated our techniques in an animal model. For the animal protocol; six swine were used as liver donors and randomized to 12 hours of CS in UW (n = 3) or 12 hours of HMP using Vasosol solution (n = 3). LTx was performed in six swine. Animals survived until postoperative day 5. RESULTS: For the discard protocol, mean HMP time was 6.7 +/- 1.8 hours. Target flow was 0.7 mL/g liver/min. PV and HA pressure ranged from 3 to 5 and 12 to 18 mm Hg, respectively. All grafts were maintained at 3 degrees C to 5 degrees C during HMP. For the animal protocol, all recipients had good liver function and survived to postoperative day 5. AST and TBili were similar between CS and HMP. CONCLUSIONS: Our method of liver HMP appears to be a safe and reliable method to preserve livers. A clinical trial is now underway to evaluate this technique in human LTx.

Pushing the envelope in renal preservation; improved results with novel perfusate modifications for pulsatile machine perfusion of cadaver kidneys.

INTRODUCTION: Novel preservation techniques may diminish ischemia/reperfusion (I/R) injury. Our preservation laboratory has modified Belzer MPS for machine perfusion (MP) with prostaglandin E1 (PGE 1), nitroglycerin (NTG), and polyethylene glycol-superoxide dismutase (PEG-SOD) to attenuate I/R injury. We reviewed our recent experience using this novel formulation (NF) compared with standard perfusates. RESULTS: Between January 1998 and March 2000, 1060 consecutive kidneys were preserved in our laboratory. One hundred forty-eight kidneys (14%) were discarded. Fifty-eight percent of kidneys during this time period underwent MP (n = 532). En bloc kidney pairs were randomly assigned to pulsatile MP using Waters RM3 or MOX-100 perfusion systems using 1 of 3 perfusates; NF (NF; n = 119), Belzer MPS (MPS; n = 201), or Belzer II albumin gluconate (ALB; n = 212) Significant improvements in delayed graft function (DGF) rate were seen with NF versus other perfusates (8% vs 14% vs 19%, respectively; P =.03). At 6 months, graft survival was significantly improved with NF compared with MPS and ALB (96% vs 90% vs 87%, respectively; P =.03). NF also produced a significantly higher percentage of recipients with a serum creatinine level < or = 1.5 mg/dL. CONCLUSIONS: Novel modifications of standard MP perfusate improved outcomes after renal transplantation. Preservation-based interventions targeted to ameliorate I/R injury can improve outcomes and may allow expansion of the donor pool.

Liver transplantation for autoimmune hepatitis.

Publications about liver transplantation (LTX) for autoimmune hepatitis (AIH) have started to emerge, but many issues remain unresolved. We reviewed data on 32 patients transplanted for AIH to determine how pretransplantation and posttransplantation characteristics correlate with recipient outcome, including disease recurrence. Recipients were 37+/- 14 years old; 30 of 32 were women. Most had chronic disease (8 +/- 6 years); 25% had fulminant failure. The majority had ascites (91%), jaundice (88%), elevated prothrombin time (18 +/- 3 seconds), and hypoalbuminemia (2.7 +/- 0.6 g/dL). All had hypergammaglobulinemia (3.0 +/- 1.0 g/dL) and autoantibodies (72% antinuclear, 74% smooth muscle). Only one was HLA A1-B8-DR3 positive. Other autoimmune disorders affected 25% of patients; half improved after transplantation. Actuarial survival was 81% at 1 and 2 years posttransplantation. There was a high frequency of rejection (75% of recipients had 1.7 +/- 0.8 episodes), and 39% of rejections required OKT3. Among 24 recipients with long-term follow-up (27 +/- 14 months), histologically proven recurrent AIH occurred in 25%, 15 +/- 2 months posttransplantation; half (3 patients) required retransplantation 11 +/- 3 months after diagnosis. After retransplantation 2 of 3 patients had re-recurrence within 3 months; 1 received a third LTx. Recurrence occurred in 6 of 18 patients transplanted for chronic disease vs. 0 of 6 transplanted as fulminants (P = not significant [NS]). Patients with and without recurrence had similar rejection profiles. In summary, results of LTx for AIH are excellent. However, AIH patients have a high frequency of rejection and often require OKT3. Furthermore, severe recurrent AIH sometimes develops, particularly in chronic versus fulminant AIH patients and in those already retransplanted for recurrence. Multicenter studies could elucidate the best posttransplantation immunosuppressive regimens for AIH patients.

Retransplantation for late liver graft failure: predictors of mortality.

As patient survival after orthotopic liver transplantation (OLT) improves, late complications, including late graft failure, more commonly occur and retransplantation (re-OLT) is required more often. Survival after re-OLT is poorer than after primary OLT, and given the organ shortage, it is essential that we optimize our use of scarce donor livers. We sought to identify variables that predict poor outcome after late re-OLT. Among adults who underwent OLT between September 1989 and October 1997, we identified transplant recipients who survived greater than 6 months (n = 964) and analyzed those who required late re-OLT (>/=6 months after primary OLT). We recorded the indication for the initial OLT and interval from OLT to re-OLT. We also analyzed data collected at the time of re-OLT, including age, sex, indications for primary OLT and re-OLT, United Network for Organ Sharing status, preoperative laboratory values (white blood cells, platelets, hemoglobin, albumin, bilirubin, creatinine, and prothrombin time), Child-Pugh-Turcotte score, number of rejection episodes before re-OLT, and interval between OLT and re-OLT. In addition, we analyzed surgical factors (including procedure performed and use of packed red blood cells, fresh frozen plasma, and platelets), postoperative immunosuppression, and donor factors (age, ischemic time). Forty-eight patients (5%) underwent late re-OLT at a median of 557 days (range, 195 to 2,559 days) post-OLT. Survival rates after re-OLT at 90 days, 1 year, and 5 years were 71%, 60%, and 42%, respectively. Patients surviving 90 days or greater after re-OLT had an 85% chance of surviving to 1 year. Sepsis was the leading cause of death (15 of 25 deaths; 60%). Recipient age older than 50 years (P =.04), preoperative creatinine level greater than 2 mg/dL (P =.004), and use of intraoperative blood products (packed red blood cells, P =.001; fresh frozen plasma, P =.002; platelets, P =.004) had significant impacts on survival. Late re-OLT was associated with increased mortality. Careful patient selection, with particular attention to recipient age and renal function, may help improve results and optimize our use of scarce donor livers.

Long-term medical complications in patients surviving > or = 5 years after liver transplant.

BACKGROUND: Short-term outcomes of liver transplantation are well reported. Little is known, however, about long-term results in liver recipients surviving > or =5 years. We sought to analyze long-term complications in liver recipients surviving > or =5 years after transplant, to assess their medical condition and to compare findings to the general population. METHODS: We analyzed the chart and database records of all patients (n=139) who underwent liver transplantation at a major transplant center before January 1, 1991. Outcome measures included the presence of diabetes, hypertension, heart, renal or neurological disease, osteoporosis, incidence of de novo malignancy or fracture, or other pathology, body mass index, serum cholesterol and glucose, liver function, blood pressure, frequency of laboratory and clinic follow-up, current pharmacological regimen, and late rejection episodes. RESULTS: Ninety-six patients (70%) survived > or =5 years. Compared to numbers expected based on U.S. population rates, transplant recipients had significantly higher overall prevalences of hypertension (standardized prevalence ratio [SPR]=3.07, 95% confidence interval [CI], 2.35-3.93) and diabetes (SPR=5.99, 95% CI, 4.15-8.38), and higher incidences of de novo malignancy (standardized incidence ratio [SIR]=3.94, 95% CI, 2.09-6.73), non-Hodgkin's lymphoma (SIR=28.56, 95% CI, 7.68-73.11), non-melanoma skin cancer (estimated SIR> or =3.16) and fractures in women (SIR=2.05, 95% CI, 1.12-3.43). Forty-one of 87 (47.1%) patients were obese, and 23 patients (27.4%) had elevated serum cholesterol levels (> or =240 mg/dl, 6.22 mmol/L), compared to 33% and 19.5% of U.S. adults, respectively. Prevalences of heart or peptic ulcer disease were not significantly higher. CONCLUSIONS: Liver transplantation is being performed with excellent 5-year survival. Significant comorbidities exist, however, which appear to be related to long-term immunosuppression.