OPTN/SRTR 2022 Annual Data Report: Liver.

In 2022, liver transplant activity continued to increase in the United States, with an all-time high of 9,527 transplants performed, representing a 52% increase over the past decade (2012-2022). Of these transplants, 8,924 (93.7%) were from deceased donors and 603 (6.3%) were from living donors. Liver transplant recipients were 94.5% adult and 5.5% pediatric. The overall size of the liver transplant waiting list contracted, with more patients being removed than added, although 10,548 adult patients still remained on the waiting list at the end of 2022. Alcohol-associated liver disease continued to be the leading diagnosis among both candidates and recipients, followed by metabolic dysfunction-associated steatohepatitis. Simultaneous liver-kidney transplant was the most common multiorgan combination, with 800 liver-kidney transplants performed in 2022; in addition, there were 303 new listings for kidney transplant via the safety net mechanism. Among adults added to the liver waiting list in 2021, 39.9% received a deceased donor liver transplant within 3 months; 45.7%, within 6 months; and 54.5%, within 1 year. Pretransplant mortality decreased to 12.3 deaths per 100 patient-years in 2022, although still 15.6% of removals from the waiting list were for death or being too sick for transplant. Graft and patient survival outcomes after deceased donor liver transplant improved, approximating pre-COVID-19 pandemic levels, with 5.1% mortality observed at 6 months; 6.8%, at 1 year; 12.7%, at 3 years; 19.8%, at 5 years; and 35.7%, at 10 years. Five-year graft and patient survival rates after living donor liver transplant exceeded those of deceased donor liver transplant. Candidates receiving model for end-stage liver disease exception points for hepatocellular carcinoma constituted 15.5% of transplants performed in 2022, with similar transplant rates and posttransplant outcomes compared to cases without hepatocellular carcinoma exception. In 2022, more pediatric liver transplant candidates were added to the waiting list and underwent transplant compared with either of the preceding 2 years, with an uptick in living donor liver transplant volume. Although pretransplant mortality has improved after the recent policy change prioritizing pediatric donors for pediatric recipients, still, in 2022, 50 children died or were removed from the waiting list for being too sick to undergo transplant. Posttransplant mortality among pediatric liver transplant recipients remained notable, with death occurring in 4.0% at 6 months, 6.0% at 1 year, 8.2% at 3 years, 9.8% at 5 years, and 13.9% at 10 years. Similar to adult living donor recipients, pediatric living donor recipients had better 5-year patient survival compared with deceased donor recipients.

Manufacturing and Functional Characterization of Bioengineered Liver Grafts for Extracorporeal Liver Assistance in Acute Liver Failure.

Acute Liver Failure (ALF) is a life-threatening illness characterized by the rapid onset of abnormal liver biochemistries, coagulopathy, and the development of hepatic encephalopathy. Extracorporeal bioengineered liver (BEL) grafts could offer a bridge therapy to transplant or recovery. The present study describes the manufacture of clinical scale BELs created from decellularized porcine-derived liver extracellular matrix seeded entirely with human cells: human umbilical vein endothelial cells (HUVECs) and primary human liver cells (PHLCs). Decellularized scaffolds seeded entirely with human cells were shown to adhere to stringent sterility and safety guidelines and demonstrated increased functionality when compared to grafts seeded with primary porcine liver cells (PPLCs). BELs with PHLCs were able to clear more ammonia than PPLCs and demonstrated lower perfusion pressures during patency testing. Additionally, to determine the full therapeutic potential of BELs seeded with PHLCs, longer culture periods were assessed to address the logistical constraints associated with manufacturing and transporting a product to a patient. The fully humanized BELs were able to retain their function after cold storage simulating a product transport period. Therefore, this study demonstrates the manufacture of bioengineered liver grafts and their potential in the clinical setting as a treatment for ALF.

OPTN/SRTR 2021 Annual Data Report: Liver.

In 2021, liver transplant volume continued to grow, with a record 9,234 transplants performed in the United States, 8,665 (93.8%) from deceased donors and 569 (6.2%) from living donors. There were 8,733 (94.6%) adult and 501 (5.4%) pediatric liver transplant recipients. An increase in the number of deceased donor livers corresponded to an increase in the overall transplant rate and shorter waiting times, although still 10.0% of livers that were recovered were not transplanted. Alcohol-associated liver disease was the leading indication for both waitlist registration and liver transplant in adults, outpacing nonalcoholic steatohepatitis, while biliary atresia remained the leading indication for children. Related to allocation policy changes implemented in 2019, the proportion of liver transplants performed for hepatocellular carcinoma has decreased. Among adult candidates listed for liver transplant in 2020, 37.7% received a deceased donor liver transplant within 3 months, 43.8% within 6 months, and 53.3% within 1 year. Pretransplant mortality improved for children following implementation of acuity circle-based distribution. Short-term graft and patient survival outcomes up to 1 year worsened for adult deceased and living donor liver transplant recipients, which is a reversal of previous trends and coincided with the onset of the COVID-19 pandemic in early 2020. Longer-term outcomes among adult deceased donor liver transplant recipients were unaffected, with overall posttransplant mortality rates of 13.3% at 3 years, 18.6% at 5 years, and 35.9% at 10 years. Pretransplant mortality improved for children following implementation of acuity circle-based distribution and prioritization of pediatric donors to pediatric recipients in 2020. Pediatric living donor recipients had superior graft and patient survival outcomes compared with deceased donor recipients at all time points.

Self-ejection of salts and other foulants from superhydrophobic surfaces to enable sustainable anti-fouling.

A recently discovered phenomenon in which crystalline structures grown from evaporating drops of saline water self-eject from superhydrophobic materials has introduced new possibilities for the design of anti-fouling materials and sustainable processes. Some of these possibilities include evaporative heat exchange systems using drops of saline water and new strategies for handling/processing waste brines. However, the practical limits of this effect using realistic, non-ideal source waters have yet to be explored. Here, we explore how the presence of various model aquatic contaminants (colloids, surfactants, and calcium salt) influences the self-ejection phenomena. Counterintuitively, we find that the addition of "contaminant" chemistries can enable ejection under conditions where ejection was not observed for waters containing only sodium chloride salt (e.g., from smooth hydrophobic surfaces), and that increased concentrations of both surfactants and colloids lead to longer ejection lengths. This result can be attributed to decreased crystallization nucleation time caused by the presence of other species in water.

Lower survival and higher rates of cirrhosis in patients with ROUX-EN-Y gastric bypass hospitalised with alcohol-associated hepatitis.

OBJECTIVE: The incidence of alcohol-associated liver disease (ALD) is increasing, and weight loss surgery is more common due to the obesity epidemic. Roux-en-Y gastric bypass (RYGB) is associated with alcohol use disorder and ALD; however, its impact on outcomes in patients hospitalised for alcohol-associated hepatitis (AH) is unclear. DESIGN: We performed a single-centre, retrospective study of patients with AH from June 2011 to December 2019. Primary exposure was the presence of RYGB. The primary outcome was inpatient mortality. Secondary outcomes included overall mortality, readmissions and cirrhosis progression. RESULTS: 2634 patients with AH met the inclusion criteria; 153 patients had RYGB. Median age of the entire cohort was 47.3 years; median Model for End Stage Liver Disease - Sodium (MELD-Na) was 15.1 in the study group versus 10.9 in the control group. There was no difference in inpatient mortality between the two groups. On logistic regression, increased age, elevated body mass index, MELD-Na >20 and haemodialysis were all associated with higher inpatient mortality. RYGB status was associated with increased 30-day readmission (20.3% vs 11.7%, p<0.01), development of cirrhosis (37.5% vs 20.9%, p<0.01) and overall mortality (31.4% vs 24%, p=0.03). CONCLUSIONS: Patients with RYGB have higher rates of readmissions, cirrhosis and overall mortality after discharge from hospital for AH. Allocation of additional resources on discharge may improve clinical outcomes and reduce healthcare expenditure in this unique patient population.

Outcomes of patients with acute liver failure listed for liver transplantation: A multicenter prospective cohort analysis.

Liver transplantation (LT) is a life-saving treatment for patients with acute liver failure (ALF). Currently, there are few detailed data regarding long-term outcomes after LT for ALF. We combined prospective data from the Acute Liver Failure Study Group (ALFSG) Registry with those of the Scientific Registry of Transplant Recipients (SRTR) to assess outcomes among consecutive patients with ALF listed for LT. Cohort analysis of detailed pretransplantation data for patients listed for LT for ALF in the ALFSG Registry between January 1998 and October 2018 matched with transplantation-related data from the SRTR. Primary outcomes were 1- and 3-year post-LT patient survival. Secondary outcome was receipt of LT; independent associations with successful receipt of LT were determined using multivariable logistic regression. Of 624 patients with ALF listed for LT, 398 (64%) underwent LT, 100 (16%) died without LT, and 126 (20%) recovered spontaneously. Among LT recipients, etiologies included seronegative/indeterminate (22%), drug-induced liver injury (18%), acetaminophen overdose (APAP; 16%), and viral hepatitis (15%). The 1- and 3-year post-LT patient survival rates were 91% and 90%, respectively. Comparing those dying on the waiting list versus with those who received LT, the former had more severe multiorgan failure, reflected by increased vasopressor use (65% vs. 22%), mechanical ventilation (84% vs. 57%), and renal replacement therapy (57% vs. 30%; p < 0.0001 for all). After adjusting for relevant covariates, age (adjusted odds ratio [aOR] 1.02, 95% confidence interval [CI] 1.00-1.04), APAP etiology (aOR 2.72, 95% CI 1.42-5.23), requirement for vasopressors (aOR 4.19, 95% CI 2.44-7.20), Grade III/IV hepatic encephalopathy (aOR 2.47, 95% CI 1.29-4.72), and Model for End-Stage Liver Disease (MELD) scores (aOR 1.05, 95% CI 1.02-1.09; p < 0.05 for all) were independently associated with death without receipt of LT. Post-LT outcomes for ALF are excellent in this cohort of very ill patients. The development of multiorgan failure while on the transplantation list and APAP ALF etiology were associated with a lower likelihood of successful receipt of LT.

Patient-reported outcomes in HCC: A scoping review by the Practice Metrics Committee of the American Association for the Study of Liver Diseases.

BACKGROUND AND AIMS: HCC is a leading cause of mortality in patients with advanced liver disease and is associated with significant morbidity. Despite multiple available curative and palliative treatments, there is a lack of systematic evaluation of patient-reported outcomes (PROs) in HCC. APPROACH AND RESULTS: The American Association for the Study of Liver Diseases Practice Metrics Committee conducted a scoping review of PROs in HCC from 1990 to 2021 to (1) synthesize the evidence on PROs in HCC and (2) provide recommendations on incorporating PROs into clinical practice and quality improvement efforts. A total of 63 studies met inclusion criteria investigating factors associated with PROs, the relationship between PROs and survival, and associations between HCC therapy and PROs. Studies recruited heterogeneous populations, and most were cross-sectional. Poor PROs were associated with worse prognosis after adjusting for clinical factors and with more advanced disease stage, although some studies showed better PROs in patients with HCC compared to those with cirrhosis. Locoregional and systemic therapies were generally associated with a high symptom burden; however, some studies showed lower symptom burden for transarterial radiotherapy and radiation therapy. Qualitative studies identified additional symptoms not routinely assessed with structured questionnaires. Gaps in the literature include lack of integration of PROs into clinical care to guide HCC treatment decisions, unknown impact of HCC on caregivers, and the effect of palliative or supportive care quality of life and health outcomes. CONCLUSION: Evidence supports assessment of PROs in HCC; however, clinical implementation and the impact of PRO measurement on quality of care and longitudinal outcomes need future investigation.

Clinical Impact of Antecedent Bariatric Surgery on Liver Transplant Outcomes: A Retrospective Matched Case-control Study.

BACKGROUND: Bariatric surgery (BS) may be associated with significant malabsorption and nutritional deficiencies. METHODS: Between March 1987 and January 2017, we performed 922 liver transplants (LT) at our institution; 33 had antecedent BS. We matched the BS cohort to LT recipients without BS (1:3 matching) based on exact matching for gender and cancer and inverse variance matching for age, LT body mass index, MELD score, and transplant date. RESULTS: We analyzed outcomes in 132 LT recipients (33 BS; 99 non-BS). The BS cohort comprised 26 (79%) women with a mean age of 52.4 years. The BS procedures included 20 Roux-en-Y gastric bypass (61%), 6 jejunoileal bypass (18%), 3 gastric band (9%), 2 sleeve gastrectomy (6%), and 1 duodenal switch (3%). The primary indications for LT listing were alcoholic cirrhosis (9; 27%), nonalcoholic steatohepatitis (7; 21%), hepatitis C (8; 24%), and hepatocellular carcinoma (3; 9%). At LT, body mass index for the BS cohort was 29.6, and MELD was 24. Compared with matched controls, BS recipients did not have longer LT length of hospital stay (17.8 versus 15.7 d, P = 0.71), longer intensive care unit length of stay (5.3 versus 4.1 d, P = 0.16), or higher 30-day complication rate (76% versus 85%, P = 0.43). Overall patient survival was similar (1- and 3-y survival was 90.1% and 75.9% for BS; 90.9% and 76.4% for non-BS, P = 0.34). CONCLUSIONS: A history of BS does not portend a deleterious effect on LT outcomes.

Recurrence of Hepatocellular Carcinoma in Hepatitis C Virus (HCV) Liver Transplant Recipients Treated with Pretransplant Direct-Acting Antiviral (DAA) Therapy.

BACKGROUND: Direct-acting antivirals (DAAs) have revolutionized the treatment of hepatitis C virus (HCV). The impact of DAAs on recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) remains uncertain. OBJECTIVE: We aimed to evaluate the risk of HCC recurrence in LT recipients cleared of HCV with DAAs at the time of LT compared to a control group of LT recipients who were viremic at the time of LT. METHODS: The study was a single-center, retrospective cohort study of patients undergoing LT for HCV-related HCC from 2002 to 2017. We compared time to post-LT HCC recurrence in patients with a sustained virological response (SVR) from DAAs prior to LT (DAA group) to patients who were viremic at LT (HCV+ group) using Kaplan-Meier analysis. We performed a secondary analysis comparing post-LT HCC recurrence in the DAA group to LT recipients with SVR from interferon-based treatment prior to LT (IFN group). RESULTS: One hundred fifty-one patients underwent LT for HCC related to HCV: 34 patients in DAA group, 95 patients in HCV+ group, and 22 in IFN group. Kaplan-Meier estimates of being HCC free were 96.2, 96.2, and 78.8% at 6, 12, and 24 months in DAA group, respectively, and 100, 98.6, and 95.8% at 6, 12, and 24 months in the HCV+ group, respectively; p = 0.08. There was no difference observed for HCC recurrence between the DAA and IFN groups. In a multivariate Cox proportional hazards model, DAA use increased the risk of post-LT HCC recurrence (HR 5.2, 95% CI 0.9-29.81, p = 0.07). CONCLUSIONS: A strong trend was observed on both Kaplan-Meier and multivariate analyses toward increased post-LT HCC recurrence in patients who achieved SVR prior to LT with DAAs compared to patients who were viremic at LT. Caution is required when considering pre-LT treatment of HCV with DAAs in patients with HCC.

Basic principles of liver allocation and development over the years.

PURPOSE OF REVIEW: Prior to the enactment of the National Organ Transplant Act in 1984, there was no organized system to allocate donor organs in the United States. The process of liver allocation has come a long way since then, including the development and implementation of the Model for End-stage Liver Disease, which is an objective estimate of risk of mortality among candidates awaiting liver transplantation. RECENT FINDINGS: The Liver Transplant Community is constantly working to optimize the distribution and allocation of scare organs, which is essential to promote equitable access to a life-saving procedure in the setting of clinical advances in the treatment of liver disease. Over the past 17 years, many changes have been made. Most recently, liver distribution changed such that deceased donor livers will be distributed based on units established by geographic circles around a donor hospital rather than the current policy, which uses donor service areas as the unit of distribution. In addition, a National Liver Review Board was created to standardize the process of determining liver transplant priority for candidates with exceptional medical conditions. The aim of these changes is to allocate and distribute organs in an efficient and equitable fashion. SUMMARY: The current review provides a historical perspective of liver allocation and the changing landscape in the United States.

Pulmonary Mycobacterium Spindle Cell Pseudotumor in Patient With Liver Transplant.

We report a case of liver transplant patient who presented with lung masses, found to be Mycobacterium spindle cell pseudotumors. The masses demonstrated hypermetabolic activities on positron emission tomography. Core biopsy revealed sheets of spindle histiocytic cells with abundant acid-fast bacilli identified as Mycobacterium avium-intracellulare complex. This finding is a rare presentation of Mycobacterium infection, mainly nontuberculous Mycobaterium. It is characterized by a benign, spindle cell mass-forming reaction. Most of the reported cases had acquired immune deficiency syndrome or organ transplant. Histopathology illustrating the proliferation of spindle cell shaped histiocytes containing numerous acid-fast bacilli is the gold standard for diagnosis. The standard treatment has not been well established; previously reported cases followed the standard treatment for Mycobacterium based on organ involvement. Our case is the first case to our knowledge that reports pulmonary Mycobacterium spindle cell pseudotumors in a liver transplant recipient.

Direct-Acting Antiviral Therapy for Hepatitis C Infection in a Large Immigrant Community.

Hepatitis C treatment has rapidly evolved with the arrival of direct-acting antiviral therapy. Sustained virologic response (SVR) rates in clinical trials are high but it is unknown how this translates to the immigrant community. Data from December 2013 to September 2015 was collected from a Midwest academic and community practice with a large immigrant population. There were 802 patients with an overall SVR rate of 88%. Ledipasvir/sofosbuvir was associated with favorable response among genotype 1 and 4 patients compared to other regimens (p < 0.001 and p = 0.05). Factors associated with treatment failure included advanced liver disease, male gender, East African/Middle Eastern ethnicity, and non-compliance. Patients with genotype 4 had lower SVR rates than other genotypes (58% vs. 89%, p < 0.001), particularly among East Africans (40% vs. 82% for other ethnicities). Our SVR rate for genotype 4 infection is lower than clinical trials and may be related to cultural, biologic and socioeconomic factors.

Three-dimensional Printing of Thermoplastic Materials to Create Automated Syringe Pumps with Feedback Control for Microfluidic Applications.

Microfluidics has become a critical tool in research across the biological, chemical, and physical sciences. One important component of microfluidic experimentation is a stable fluid handling system capable of accurately providing an inlet flow rate or inlet pressure. Here, we have developed a syringe pump system capable of controlling and regulating the inlet fluid pressure delivered to a microfluidic device. This system was designed using low-cost materials and additive manufacturing principles, leveraging three-dimensional (3D) printing of thermoplastic materials and off-the-shelf components whenever possible. This system is composed of three main components: a syringe pump, a pressure transducer, and a programmable microcontroller. Within this paper, we detail a set of protocols for fabricating, assembling, and programming this syringe pump system. Furthermore, we have included representative results that demonstrate high-fidelity, feedback control of inlet pressure using this system. We expect this protocol will allow researchers to fabricate low-cost syringe pump systems, lowering the entry barrier for the use of microfluidics in biomedical, chemical, and materials research.

Clinical Significance of Pulmonary Nodules in the Pretransplant Evaluation of Liver Transplant Recipients With Hepatocellular Carcinoma.

OBJECTIVES: Pulmonary nodules are common in patients with hepatocellular carcinoma who are being evaluated for a possible liver transplant. MATERIALS AND METHODS: In this retrospective study, we analyzed the records of liver transplant recipients at our institution with a primary diagnosis of hepatocellular carcinoma who received transplants between 2000 and 2015. All patients had magnetic resonance imaging-confirmed disease within Milan criteria and a concurrent staging chest computed tomography. Patient survival was estimated using Kaplan-Meier methods and compared between pulmonary nodule characteristic groups. A Cox proportional hazards model was constructed for adjusted analysis. RESULTS: Of the 197 liver transplant recipients who met our study inclusion criteria (median follow-up, 40 mo), 115 (58.4%) had a total of 231 pulmonary nodules, with 57 (49.6%) having multiple nodules and 108 (93.9%) having nodules ≤ 1 cm. The presence of pulmonary nodules did not negatively affect patient survival, per our univariate and multivariate analysis, nor did their presence affect their number, location, laterality, shape, edge, density, or the presence of calcifications (P ≥.05). However, pulmonary nodules ≥ 1 cm were associated with decreased overall survival. CONCLUSIONS: In our pretransplant evaluation of patients with hepatocellular carcinoma, pulmonary nodules ≤ 1 cm did not portend worse patient or graft survival posttransplant.