Intraoperative vascular air embolism and intracardiac thrombosis complicating liver transplantation: a case report.

BACKGROUND: Intracardiac thrombus and vascular air embolism represent rare complications in the context of orthotopic liver transplantation. While isolated reports exist for intracardiac thrombus and vascular air embolism during orthotopic liver transplantation, this report presents the first documentation of their simultaneous occurrence in this surgical setting. CASE PRESENTATION: This case report outlines the clinical course of a 60-year-old white female patient with end-stage liver disease complicated by portal hypertension, ascites, and hepatocellular carcinoma. The patient underwent orthotopic liver transplantation and encountered concurrent intraoperative complications involving intracardiac thrombus and vascular air embolism. Transesophageal echocardiography revealed the presence of air in the left ventricle and a thrombus in the right atrium and ventricle. Successful management ensued, incorporating hemodynamic support, anticoagulation, and thrombolytic therapy, culminating in the patient's discharge after a week. CONCLUSIONS: This report highlights the potential for simultaneous intraoperative complications during orthotopic liver transplantation, manifesting at any phase of the surgery. It underscores the critical importance of vigilant monitoring throughout orthotopic liver transplantation to promptly identify and effectively address these rare yet potentially catastrophic complications.

Development of a portable abdominal normothermic regional perfusion (A-NRP) program in the United States.

In situ abdominal normothermic regional perfusion (A-NRP) has been used for liver transplantation (LT) with donation after circulatory death (DCD) liver grafts in Europe with excellent results; however, adoption of A-NRP in the United States has been lacking. The current report describes the implementation and results of a portable, self-reliant A-NRP program in the United States. Isolated abdominal in situ perfusion with an extracorporeal circuit was achieved through cannulation in the abdomen or femoral vessels and inflation of a supraceliac aortic balloon and cross-clamp. The Quantum Transport System by Spectrum was used. The decision to use livers for LT was made through an assessment of perfusate lactate (q15min). From May to November 2022, 14 A-NRP donation after circulatory death procurements were performed by our abdominal transplant team (N = 11 LT, N = 20 kidney transplants, and 1 kidney-pancreas transplant). The median A-NRP run time was 68 minutes. None of the LT recipients had post-reperfusion syndrome, nor were there any cases of primary nonfunction. All livers were functioning well at the time of maximal follow-up with zero cases of ischemic cholangiopathy. The current report describes the feasibility of a portable A-NRP program that can be used in the United States. Excellent short-term post-transplant results were achieved with both livers and kidneys procured from A-NRP.

Combined Sleeve Gastrectomy with Liver Transplant in Patients with Obesity: a Feasibility Study.

BACKGROUND: Nonalcoholic steatohepatitis (NASH) associated with obesity is one of the leading causes of liver failure requiring transplant, yet guidelines for the management of obesity in these scenarios are not always followed. In order to decrease incidence of NASH in the new liver, we studied the feasibility of simultaneous liver transplant and bariatric surgery. MATERIALS AND METHODS: We retrospectively identified patients who underwent simultaneous liver transplant and sleeve gastrectomy at our hospital site between November 24, 2019, and April 14, 2022. Demographics, surgical data, postoperative adverse events, and weight loss data were collected. RESULTS: Ten patients met inclusion criteria. Mean body mass index (BMI) at the time of transplant was 43.1 ± 5.3 kg/m2, and mean length of hospital stay was 10.8 ± 5.22 days. Within 30 days after surgery, 7 patients reported adverse effects, and 2 were readmitted. Mean BMI at 6-month follow-up was 30.6 ± 2.5 kg/m2. Mean percentage excess weight (in pounds) loss was 48.1 ± 11.4%, 58.6 ± 8.9%, and 66.1 ± 15.3% at 3-, 6-, and 12-month follow-up, respectively. Three patients had an increase in weight at 12-month follow-up when compared to 6-month follow-up. Most patients required fewer comorbidity-related medications, and none reported adverse effects related to sleeve gastrectomy. CONCLUSIONS: Bariatric surgery at the time of liver transplant is safe and has minimal adverse effects. Results include substantial postoperative weight loss, improvement in comorbidities, and decreased risk of NASH in the new liver. Further studies with larger cohorts are required to confirm the findings of this study.

Radiation Segmentectomy for the Treatment of Solitary Hepatocellular Carcinoma: Outcomes Compared with Those of Surgical Resection.

PURPOSE: To investigate the outcomes of radiation segmentectomy (RS) versus standard-of-care surgical resection (SR). MATERIALS AND METHODS: A multisite, retrospective analysis of treatment-naïve patients who underwent either RS or SR was performed. The inclusion criteria were solitary hepatocellular carcinoma ≤8 cm in size, Eastern Cooperative Oncology Cohort performance status of 0-1, and absence of macrovascular invasion or extrahepatic disease. Target tumor and overall progression, time to progression (TTP), and overall survival rates were assessed. Outcomes were censored for liver transplantation. RESULTS: A total of 123 patients were included (RS, 57; SR, 66). Tumor size, Child-Pugh class, albumin-bilirubin score, platelet count, and fibrosis stage were significantly different between cohorts (P ≤ .01). Major adverse events (AEs), defined as grade ≥3 per the Clavien-Dindo classification, occurred in 0 patients in the RS cohort vs 13 (20%) patients in the SR cohort (P < .001). Target tumor progression occurred in 3 (5%) patients who underwent RS and 5 (8%) patients who underwent SR. Overall progression occurred in 19 (33%) patients who underwent RS and 21 (32%) patients who underwent SR. The median overall TTP was 21.9 and 29.4 months after RS and SR, respectively (95% confidence interval [CI], 15.5-28.2 and 18.5-40.3, respectively; P = .03). Overall TTP subgroup analyses showed no difference between treatment cohorts with fibrosis stages 3-4 (P = .26) and a platelet count of <150 × 109/L (P = .29). The overall progression hazard ratio for RS versus SR was not significant per the multivariate Cox regression analysis (1.16; 95% CI, 0.51-2.63; P = .71). The median overall survival was not reached for either of the cohorts. Propensity scores were calculated but were too dissimilar for analysis. CONCLUSIONS: RS and SR were performed in different patient populations, which limits comparison. RS approached SR outcomes, with a lower incidence of major AEs, in patients who were not eligible for hepatectomy.

Using the electronic medical record to increase testing for HIV and hepatitis C virus in an Appalachian emergency department.

BACKGROUND: The ongoing Appalachian opioid epidemic has led to increasing hepatitis C virus (HCV) infections among people who inject drugs (PWID), and Human Immunodeficiency Virus (HIV) outbreaks have been observed. The primary aim of this study was to assess the potential increase in screening for HIV and HCV in an academic central Appalachian emergency department (ED) through the use of Best Practice Alerts (BPAs) in the electronic medical record (EMR). A secondary aim was to assess for an increase in linkage to care using patient navigators. METHODS: EMR algorithms based on current Centers for Disease Control and Prevention HIV and HCV testing recommendations were created that triggered Best Practice Alerts (BPAs), giving providers a one-click acceptance option to order HIV and/or HCV testing. Placards were placed in care areas, informing patients of the availability of routine screening. Patient navigators facilitated linkage to care for seropositive patients. RESULTS: The BPA appeared 58,936 times on 21,098 patients eligible for HIV screening and 24,319 times on 11,989 patients eligible for HCV screening over a one-year period. Of those, 7106 (33.7%) patients were screened for HIV and 3496 (29.2%) patients were screened for HCV, for an overall testing increase of 2269% and 1065% for HIV and HCV, respectively. Linkage to care increased by 15% for HIV to 100, and 14% for HCV to 64%. CONCLUSION: HIV and HCV screening and linkage to care were increased in an academic ED setting in central Appalachia using EMR alerts. This approach could be utilized in multiple ambulatory settings. Increased testing and earlier linkage to care may help combat the current injection drug use-related HCV epidemic and avoid additional HIV outbreaks.

The use of neoadjuvant lobar radioembolization prior to major hepatic resection for malignancy results in a low rate of post hepatectomy liver failure.

BACKGROUND: Neoadjuvant yttrium-90 transarterial radioembolization (TARE) is increasingly being used as a strategy to facilitate resection of otherwise unresectable tumors due to its ability to generate both tumor response and remnant liver hypertrophy. Perioperative outcomes after the use of neoadjuvant lobar TARE remain underinvestigated. METHODS: A single center retrospective review of patients who underwent lobar TARE prior to major hepatectomy for primary or metastatic liver cancer between 2007 and 2018 was conducted. Baseline demographics, radioembolization parameters, pre- and post-radioembolization volumetrics, intra-operative surgical data, adverse events, and post-operative outcomes were analyzed. RESULTS: Twenty-six patients underwent major hepatectomy after neoadjuvant lobar TARE. The mean age was 58.3 years (17-88 years). 62% of patients (n=16) had primary liver malignancies while the remainder had metastatic disease. Liver resection included right hepatectomy or trisegmentectomy, left or extended left hepatectomy, and sectorectomy/segmentectomy in 77% (n=20), 8% (n=2), and 15% (n=4) of patients, respectively. The mean length of stay was 8.3 days (range, 3-33 days) and there were no grade IV morbidities or 90-day mortalities. The incidence of post hepatectomy liver failure (PHLF) was 3.8% (n=1). The median time to progression after resection was 4.5 months (range, 3.3-10 months). Twenty-three percent (n=6) of patients had no recurrence. The median survival was 28.9 months (range, 16.9-46.8 months) from major hepatectomy and 37.6 months (range, 25.2-53.1 months) from TARE. CONCLUSIONS: Major hepatectomy after neoadjuvant lobar radioembolization is safe with a low incidence of PHLF.

Outcomes of Minimally Invasive Versus Open Major Hepatic Resection.

Introduction: Minimally invasive major hepatic resection (MIMHR) is increasingly being performed in tertiary centers using either hand-assisted laparoscopic surgery (HALS) or totally laparoscopic surgery (TLS). The outcomes data of MIMHR are scarce, especially in comparison to open major hepatic resection (OMHR). Our aim was to compare 90-day outcomes in major hepatic resections when minimally invasive approaches are attempted. Methods and Procedures: At our institution, minimally invasive liver resection was formally introduced in January 2007, initially using the HALS approach. Since then, the use of TLS approach has increased. We collected data on all patients who underwent major liver resection between January 2007 and December 2017 at our institution. In an intention to treat fashion, we then compared MIMHR to OMHR. Results: From January 2007 to December 2017, 669 patients underwent liver resection. Of these, 203 patients (30%) underwent major hepatic resection and MIMHR and OMHR were performed in 68 (33%) and 135 (67%) patients, respectively. The rate of conversion from minimally invasive to open was 30.9%. Overall, there were no significant differences in 90-day mortality (2.9% versus 1.5%; P = .499) or major complications (14.7% versus 14.8%; P = .985). MIMHR was associated with a shorter average postoperative hospital stay (6.2 days versus 7.9 days; P = .0110) and shorter average ICU stay (0.66 days versus 0.90 days; P = .0299) compared with OMHR. Conclusions: The minimally invasive approach to major liver resection is a safe and reasonable alternative to an open approach when performed by a surgeon experienced with the relevant surgical techniques. MIMHR may be associated with similar outcomes and a shorter postoperative hospital stay with no increase in 90-day postoperative complications to OMHR.

Kidney transplantation on extracorporeal life support for primary cardiac allograft dysfunction.

Patients undergoing heart-kidney transplants who have primary graft dysfunction (PGD) of the heart are at risk of losing both organs, which may cause reluctance on the part of the transplant team to proceed with transplanting the kidney while the transplanted heart is being supported by mechanical device. We describe a case series in which 2 patients received kidney transplants while on veno-arterial ECMO support for PGD after heart transplant. Both patients are alive more than 1 year following transplant, with good cardiac and renal function and no signs of cardiac rejection. Kidney transplant surgery is safe for patients on veno-arterial ECMO support for cardiac PGD. It allows the heart recipient to receive a kidney from the same donor with both immunologic and survival advantages.

Intraoperative Events in Liver Transplantation Using Donation After Circulatory Death Donors.

Liver grafts from donation after circulatory death (DCD) are a source of organs to decrease wait-list mortality. While there have been lower rates of graft loss, there are concerns of an increased incidence of intraoperative events in recipients of DCD grafts. We aim to look at the incidence of intraoperative events between recipients of livers from DCD and donation after brain death (DBD) donors. We collected data for 235 DCD liver recipients between 2006 and 2017. We performed a 1:1 propensity match between these patients and patients with DBD donors. Variables included recipient age, liver disease etiology, biological Model for End-Stage Liver Disease (MELD) score, allocation MELD score, diagnosis of hepatocellular carcinoma, and year of transplantation. DCD and DBD groups had no significant differences in incidence of postreperfusion syndrome (P = 0.75), arrhythmia requiring cardiopulmonary resuscitation (P = 0.66), and treatments for hyperkalemia (P = 0.84). In the DCD group, there was a significant increase in amount of total intraoperative and postreperfusion blood products (with exception of postreperfusion packed red blood cells) utilized (P < 0.05 for all products), significant differences in postreperfusion thromboelastography parameters, as well as inotropes and vasopressors used (P < 0.05 for all infusions). There was no difference in patient (P = 0.49) and graft survival (P = 0.10) at 1, 3, and 5 years. In conclusion, DCD grafts compared with a cohort of DBD grafts have a similar low incidence of major intraoperative events, but increased incidence of transient vasopressor/inotropic usage and increased blood transfusion requirements. This does not result in differences in longterm outcomes. While centers should continue to look at DCD liver donors, they should be cognizant regarding intraoperative care to prevent adverse outcomes.

Intraregional model for end-stage liver disease score variation in liver transplantation: Disparity in our own backyard.

Variation in average Model for End-Stage Liver Disease (MELD) score at liver transplantation (LT) by United Network for Organ Sharing (UNOS) regions is well documented. The present study aimed to investigate MELD variation at the interregional, intraregional, and intra-donation service area (DSA) levels. Patients undergoing LT between 2015 and 2016 were obtained from the UNOS standard analysis and research file. The distribution of allocation MELD score including median, skew, and kurtosis was examined for all transplant programs. Intraregional median allocation MELD varied significantly within all 11 UNOS regions. The largest variation between programs was seen in region 5 (MELD 24.0 versus 38.5) and region 3 (MELD 20.5 versus 32.0). Regions 1, 5, and 9 had the largest proportion of programs with a highly negative skewed MELD score (50%, 57%, and 57%, respectively), whereas regions 3, 6, 10, and 11 did not have any programs with a highly negative skew. MELD score distribution was also examined in programs located in the same DSA, where no barriers exist and theoretically no significant difference in allocation should be observed. The largest DSA variation in median allocation MELD score was seen in NYRT-OP1 LiveOnNY (MELD score variation 11), AZOB-OP1 Donor Network of Arizona (MELD score variation 11), MAOB-OP1 New England Organ Bank (MELD score variation 9), and TXGC-OP1 LifeGift Organ Donation Ctr (MELD score variation 9). In conclusion, the present study demonstrates that this MELD disparity is not only present at the interregional level but can be seen within regions and even within DSAs between programs located as close as several city blocks away. Although organ availability likely accounts for a component of this disparity, the present study suggests that transplant center behavior may also play a significant role. Liver Transplantation 24 488-496 2018 AASLD.

Looking inward: The impact of operative time on graft survival after liver transplantation.

BACKGROUND: Operative time often has been cited as an important factor for postoperative outcomes. Despite this belief, most efforts to improve liver transplant outcomes have largely focused on only patient and donor factors, and little attention has been paid on operative time. The primary objective of this project was to determine the impact of operative time on graft survival after liver transplant. METHODS: A retrospective review of 2,877 consecutive liver transplants performed at a single institution was studied. Data regarding recipient, donor, and operative characteristics, including detailed granular operative times were collected prospectively and retrospectively reviewed. Using an instrument variable approach, Cox multivariate modeling was performed to assess the impact of operative time without the confounding of known and unknown variables. RESULTS: Of the 2,396 patients who met the criteria for review, the most important factors determining liver transplant graft survival included recipient history of Hepatitis C (hazard ratio 1.45, P = .02), donor age (hazard ratio 1.23, P = .03), use of liver graft from donation after cardiac death donor (hazard ratio 1.50, P < .01), and operative time (hazard ratio 1.26, P = .01). In detailed analysis of stages of the liver transplant operation, the time interval from incision to anhepatic phase was associated with graft survival (hazard ratio 1.33; P = .02). CONCLUSION: Using a novel instrument variable approach, we demonstrate that operative time (in particular, the time interval from incision to anhepatic time) has a significant impact on graft survival. It also seems that some of this efficiency is under the influence of the transplant surgeon.

Oxygen-Dependent Globin Coupled Sensor Signaling Modulates Motility and Virulence of the Plant Pathogen Pectobacterium carotovorum.

Bacterial pathogens utilize numerous signals to identify the presence of their host and coordinate changes in gene expression that allow for infection. Within plant pathogens, these signals typically include small molecules and/or proteins from their plant hosts and bacterial quorum sensing molecules to ensure sufficient bacterial cell density for successful infection. In addition, bacteria use environmental signals to identify conditions when the host defenses are weakened and potentially to signal entry into an appropriate host/niche for infection. A globin coupled sensor protein (GCS), termed PccGCS, within the soft rot bacterium Pectobacterium carotovorum ssp. carotovorum WPP14 has been identified as an O2 sensor and demonstrated to alter virulence factor excretion and control motility, with deletion of PccGCS resulting in decreased rotting of a potato host. Using small molecules that modulate bacterial growth and quorum sensing, PccGCS signaling also has been shown to modulate quorum sensing pathways, resulting in the PccGCS deletion strain being more sensitive to plant-derived phenolic acids, which can function as quorum sensing inhibitors, and exhibiting increased N-acylhomoserine lactone (AHL) production. These findings highlight a role for GCS proteins in controlling key O2-dependent phenotypes of pathogenic bacteria and suggest that modulating GCS signaling to limit P. carotovorum motility may provide a means to decrease rotting of plant hosts.

Liver Transplantation for Hepatocellular Carcinoma: Impact of Wait Time at a Single Center

ABSTRACT Introduction and aim. Liver transplantation (LT) provides durable survival for hepatocellular carcinoma (HCC). However, there is continuing debate concerning the impact of wait time and acceptable tumor burden on outcomes after LT. We sought to review outcomes of LT for HCC at a single, large U.S. center, examining the influence of wait time on post-LT outcomes. Material and methods. We reviewed LT for HCC at Mayo Clinic in Florida from 1/1/2003 until 6/30/2014. Follow up was updated through 8/1/ 2015. Results. From 2003-2014,978 patients were referred for management of HCC. 376 patients were transplanted for presumed HCC within Milan criteria, and the results of these 376 cases were analyzed. The median diagnosis to LT time was 183 days (8 - 4,337), and median transplant list wait time was 62 days (0 -1815). There was no statistical difference in recurrence-free or overall survival for those with wait time of less than or greater than 180 days from diagnosis of HCC to LT. The most important predictor of long term survival after LT was HCC recurrence (HR: 18.61, p < 0.001). Recurrences of HCC as well as survival were predicted by factors related to tumor biology, including histopathological grade, vascular invasion, and pre-LT serum alpha-fetoprotein levels. Disease recurrence occurred in 13%. The overall 5-year patient survival was 65.8%, while the probability of 5-year recurrence-free survival was 62.2%. Conclusions. In this large, single-center experience with long-term data, factors of tumor biology, but not a longer wait time, were associated with recurrence-free and overall survival.

Liver Transplantation for Hepatocellular Carcinoma: Impact of Wait Time at a Single Center.

INTRODUCTION AND AIM: Liver transplantation (LT) provides durable survival for hepatocellular carcinoma (HCC). However, there is continuing debate concerning the impact of wait time and acceptable tumor burden on outcomes after LT. We sought to review outcomes of LT for HCC at a single, large U.S. center, examining the influence of wait time on post-LT outcomes. MATERIAL AND METHODS: We reviewed LT for HCC at Mayo Clinic in Florida from 1/1/2003 until 6/30/2014. Follow up was updated through 8/1/ 2015. RESULTS: From 2003-2014, 978 patients were referred for management of HCC. 376 patients were transplanted for presumed HCC within Milan criteria, and the results of these 376 cases were analyzed. The median diagnosis to LT time was 183 days (8 - 4,337), and median transplant list wait time was 62 days (0 - 1815). There was no statistical difference in recurrence-free or overall survival for those with wait time of less than or greater than 180 days from diagnosis of HCC to LT. The most important predictor of long term survival after LT was HCC recurrence (HR: 18.61, p < 0.001). Recurrences of HCC as well as survival were predicted by factors related to tumor biology, including histopathological grade, vascular invasion, and pre-LT serum alpha-fetoprotein levels. Disease recurrence occurred in 13%. The overall 5-year patient survival was 65.8%, while the probability of 5-year recurrence-free survival was 62.2%. CONCLUSIONS: In this large, single-center experience with long-term data, factors of tumor biology, but not a longer wait time, were associated with recurrence-free and overall survival.

Wait Time of Less Than 6 and Greater Than 18 Months Predicts Hepatocellular Carcinoma Recurrence After Liver Transplantation: Proposing a Wait Time "Sweet Spot".

BACKGROUND: It has been postulated that short wait time before liver transplant (LT) for hepatocellular carcinoma (HCC) results in the inclusion of tumors with aggressive biology, but prolonged wait time could result in a shift to more aggressive tumor behavior. We therefore test the hypothesis that a wait time "sweet spot" exists with a lower risk for HCC recurrence compared with the other 2 extremes. METHODS: This multicenter study included 911 patients from 3 LT centers with short, medium, and long wait times (median of 4, 7, and 13 months, respectively) who received Model for End Stage Liver Disease exception listing for HCC from 2002 to 2012. RESULTS: Wait time, defined as time from initial HCC diagnosis to LT, was less than 6 months in 32.4%, 6 to 18 months in 53.7%, and greater than 18 months in 13.9%. Waitlist dropout was observed in 18.4% at a median of 11.3 months. Probability of HCC recurrence at 1 and 5 years were 6.4% and 15.5% with wait time of less than 6 or greater than 18 months (n = 343) versus 4.5% and 9.8% with wait time of 6 to 18 months (n = 397), respectively (P = 0.049). When only pre-LT factors were considered, wait time of less than 6 or greater than 18 months (HR, 1.6; P = 0.043) and AFP greater than 400 at HCC diagnosis (HR, 3.0; P < 0.001) predicted HCC recurrence in multivariable analysis. CONCLUSIONS: This large multicenter study provides evidence of an association between very short (<6 months) or very long (>18 months) wait times and an increased risk for HCC recurrence post-LT. The so-called sweet spot of 6 to 18 months should be the target to minimize HCC recurrence.

Comparison of longterm outcomes and quality of life in recipients of donation after cardiac death liver grafts with a propensity-matched cohort.

The use of liver grafts from donation after cardiac death (DCD) has been limited due to the increased rate of graft failure, mostly related to ischemic cholangiopathy (IC). It is our hypothesis that longterm outcomes and quality of life (QOL) similar to patients undergoing liver transplantation (LT) with donation after brain death (DBD) can be achieved. Clinical outcomes of all patients undergoing DCD LT (n = 300) between 1998 and 2015 were compared with a propensity score-matched cohort of patients undergoing DBD LT (n = 300). Patients were contacted for a follow-up questionnaire and short-form (SF)-12 QOL Survey administration. Median follow-up was >5 years. Graft survival at 1-, 3-, and 5-years was 83.8%, 75.5%, and 70.1% in the DCD LT group and 88.4%, 80.3%, and 73.9% in the DBD LT group (P = 0.27). Patient survival at 1-, 3-, and 5-years was 92.3%, 86.1%, and 80.3% in the DCD LT group and 92.3%, 85.1%, and 79.5% in the DBD LT group (P = 0.81). IC developed in 11.7% and 2% of patients in the DCD LT group and DBD LT group, respectively (P < 0.001). DCD LT recipients who developed IC had inferior graft survival compared with both the DCD non-IC group (P < 0.001) and the DBD LT group (P < 0.001); no difference in graft survival was observed between the DCD non-IC group and the DBD LT group (P = 0.50). Physical and Mental Composite Scores on the SF-12 QOL questionnaire were similar between the DCD LT and DBD LT groups (44.0 versus 45.4; P = 0.34 and 51.9 versus 52.2; P = 0.83), respectively. Similar longterm survival and QOL scores can be achieved between DCD LT and DBD LT. Prevention of IC in DCD LT yields excellent graft and patient survival with virtually no difference compared with DBD LT. Liver Transplantation 23 342-351 2017 AASLD.

Validation of a Risk Estimation of Tumor Recurrence After Transplant (RETREAT) Score for Hepatocellular Carcinoma Recurrence After Liver Transplant.

IMPORTANCE: Several factors are associated with increased hepatocellular carcinoma (HCC) recurrence after liver transplantation (LT), but no reliable risk score has been established to determine the individual risk for HCC recurrence. OBJECTIVE: We aimed to develop and validate a Risk Estimation of Tumor Recurrence After Transplant (RETREAT) score for patients with HCC meeting Milan criteria by imaging. DESIGN, SETTING, AND PARTICIPANTS: Predictors of recurrence were tested in a development cohort of 721 patients who underwent LT between 2002 and 2012 at 3 academic transplant centers (University of California-San Francisco; Mayo Clinic, Rochester; and Mayo Clinic, Jacksonville) to create the RETREAT score. This was subsequently validated in a cohort of 341 patients also meeting Milan criteria by imaging who underwent LT at the University of Toronto transplant center using the C concordance statistic and net reclassification index. MAIN OUTCOMES AND MEASURES: Characteristics associated with post-LT HCC recurrence. RESULTS: A total of 1061 patients participated in the study; 77.8% (825) were men, and the median (IQR) age was 58.2 (53.3-63.9) years in the development cohort and 56.4 (51.7-61.0) years in the validation cohort (P < .001). In the development cohort of 721 patients (542 men), median α-fetoprotein (AFP) level at the time of LT was 8.3 ng/mL; 9.4% had microvascular invasion (n = 68), and 22.1% were beyond Milan criteria on explant (n = 159) owing to understaging by pretransplantation imaging. Cumulative probabilities of HCC recurrence at 1 and 5 years were 5.7% and 12.8%, respectively. On multivariable Cox proportional hazards regression, 3 variables were independently associated with HCC recurrence: microvascular invasion, AFP at time of LT, and the sum of the largest viable tumor diameter and number of viable tumors on explant. The RETREAT score was created using these 3 variables, with scores ranging from 0 to 5 or higher that were highly predictive of HCC recurrence (C statistic, 0.77). RETREAT was able to stratify 5-year post-LT recurrence risk ranging from less than 3% with a score of 0 to greater than 75% with a score of 5 or higher. The validation cohort (n = 340; 283 men) had significantly higher microvascular invasion (23.8% [n = 81], P < .001), explant beyond Milan criteria (37.3% [n = 159], P < .001), and HCC recurrence at 5 years (17.9% [n = 159], P = .03). RETREAT showed good model discrimination (C statistic, 0.82; 95% CI, 0.77-0.86) and superior recurrence risk classification compared with explant Milan criteria (net reclassification index, 0.40; P = .001) in the validation cohort. CONCLUSIONS AND RELEVANCE: We have developed and validated a simple and novel prognostic score that may improve post-LT HCC surveillance strategies and help identify patients who may benefit from future adjuvant therapies.

Oxygen and Bis(3',5')-cyclic Dimeric Guanosine Monophosphate Binding Control Oligomerization State Equilibria of Diguanylate Cyclase-Containing Globin Coupled Sensors.

Bacteria sense their environment to alter phenotypes, including biofilm formation, to survive changing conditions. Heme proteins play important roles in sensing the bacterial gaseous environment and controlling the switch between motile and sessile (biofilm) states. Globin coupled sensors (GCS), a family of heme proteins consisting of a globin domain linked by a central domain to an output domain, are often found with diguanylate cyclase output domains that synthesize c-di-GMP, a major regulator of biofilm formation. Characterization of diguanylate cyclase-containing GCS proteins from Bordetella pertussis and Pectobacterium carotovorum demonstrated that cyclase activity is controlled by ligand binding to the heme within the globin domain. Both O2 binding to the heme within the globin domain and c-di-GMP binding to a product-binding inhibitory site (I-site) within the cyclase domain control oligomerization states of the enzymes. Changes in oligomerization state caused by c-di-GMP binding to the I-site also affect O2 kinetics within the globin domain, suggesting that shifting the oligomer equilibrium leads to broad rearrangements throughout the protein. In addition, mutations within the I-site that eliminate product inhibition result in changes to the accessible oligomerization states and decreased catalytic activity. These studies provide insight into the mechanism by which ligand binding to the heme and I-site controls activity of GCS proteins and suggests a role for oligomerization-dependent activity in vivo.

Simultaneous liver and kidney transplantation in elderly patients: Outcomes and validation of a clinical risk score for patient selection.

 Introduction and aim. Many transplant programs have expanded eligibility to include patients previously ineligible because of advanced age. Outcomes of simultaneous liver-kidney transplantation (SLK) in recipients with advanced age are not known. MATERIAL AND METHODS: Data from patients undergoing transplantation between 2002 and 2015 were obtained from the UNOS Standard Analysis and Research file. RESULTS: SLK recipients aged ≥ 65 years (N = 677), SLK recipients aged < 65 years (N = 4517), and recipients of liver transplant alone(LTA) aged ≥ 65 years(N = 8495) were compared. Recipient characteristics were similar between the SLK groups. Similar patient and graft survival were observed in SLK recipients aged ≥ 65 years compared to SLK recipients aged < 65 years and LTA recipients aged ≥ 65 years. Importantly, in a subgroup analysis, superior survival was seen in the SLK group aged ≥ 65 years compared to LTA recipients aged ≥ 65 years who underwent dialysis in the week prior to transplantation (p < 0.001). A prediction model of patient survival was developed for the SLK group aged ≥ 65 years with predictors including: age ≥ 70 years (3 points), calculated MELD score (-1 to 2 points), and recipient ventilator status at the time of SLK (4 points). The risk score predicted patient survival, with a significantly inferior survival seen in patients with a score ≥ 4 (p < 0.001). CONCLUSIONS: Age should not be used as a contraindication for SLK transplantation. The validated scoring system provides a guide for patient selection and can be used when evaluating elderly patients for SLK transplantation listing.