Serum from patients with cirrhosis undergoing liver transplantation induces permeability in human pulmonary microvascular endothelial cells ex vivo.

Introduction: Patients with cirrhosis undergoing liver transplantation frequently exhibit systemic inflammation, coagulation derangements, and edema, indicating endothelial dysfunction. This syndrome may worsen after ischemia-reperfusion injury of the liver graft, coincident with organ dysfunction that worsens patient outcomes. Little is known about changes in endothelial permeability during liver transplantation. We hypothesized that sera from these patients would increase permeability in cultured human endothelial cells ex vivo. Methods: Adults with cirrhosis presenting for liver transplantation provided consent for blood collection during surgery. Sera were prepared at five time points spanning the entire operation. The barrier function of human pulmonary microvascular endothelial cells in culture was assessed by transendothelial resistance measured using the ECIS ZΘ system. Confluent cells from two different endothelial cell donors were stimulated with human serum from liver transplant patients. Pooled serum from healthy men and purified inflammatory agonists served as controls. The permeability response to serum was quantified as the area under the normalized resistance curve. Responses were compared between time points and analyzed for associations with clinical characteristics of liver transplant patients and their grafts. Results: Liver transplant sera from all time points during surgery-induced permeability in both endothelial cell lines. The magnitude of permeability change was heterogeneous between patients, and there were differences in the effects of sera on the two endothelial cell lines. In one of the cell lines, the severity of liver disease was associated with greater permeability at the start of surgery. In the same cell line, serum collected 15 min after liver reperfusion induced significantly more permeability as compared to that collected at the start of surgery. Early postreperfusion sera from patients undergoing living donor transplants induced more permeability than sera from deceased donor transplants. Sera from two exemplary cases of patients on preoperative dialysis, and one patient with an unexpectedly long warm ischemia time of the liver graft, induced exaggerated and prolonged endothelial permeability. Discussion: Serum from patients with cirrhosis undergoing liver transplantation induces permeability of cultured human pulmonary microvascular endothelial cells. Increased endothelial permeability during liver transplantation may contribute to organ injury and present a target for future therapeutics.

Angiotensin II in liver transplantation (AngLT-1): protocol of a randomised, double-blind, placebo-controlled trial.

INTRODUCTION: Catecholamine vasopressors such as norepinephrine are the standard drugs used to maintain mean arterial pressure during liver transplantation. At high doses, catecholamines may impair organ perfusion. Angiotensin II is a peptide vasoconstrictor that may improve renal perfusion pressure and glomerular filtration rate, a haemodynamic profile that could reduce acute kidney injury. Angiotensin II is approved for vasodilatory shock but has not been rigorously evaluated for treatment of hypotension during liver transplantation. The objective is to assess the efficacy of angiotensin II as a second-line vasopressor infusion during liver transplantation. This trial will establish the efficacy of angiotensin II in decreasing the dose of norepinephrine to maintain adequate blood pressure. Completion of this study will allow design of a follow-up, multicentre trial powered to detect a reduction of organ injury in liver transplantation. METHODS AND ANALYSIS: This is a double-blind, randomised clinical trial. Eligible subjects are adults with a Model for End-Stage Liver Disease Sodium Score ≥25 undergoing deceased donor liver transplantation. Subjects are randomised 1:1 to receive angiotensin II or saline placebo as the second-line vasopressor infusion. The study drug infusion is initiated on reaching a norepinephrine dose of 0.05 µg kg-1 min-1 and titrated per protocol. The primary outcome is the dose of norepinephrine required to maintain a mean arterial pressure ≥65 mm Hg. Secondary outcomes include vasopressin or epinephrine requirement and duration of hypotension. Safety outcomes include incidence of thromboembolism within 48 hours of the end of surgery and severe hypertension. An intention-to-treat analysis will be performed for all randomised subjects receiving the study drug. The total dose of norepinephrine will be compared between the two arms by a one-tailed Mann-Whitney U test. ETHICS AND DISSEMINATION: The trial protocol was approved by the local Institutional Review Board (#20-30948). Results will be posted on ClinicalTrials.gov and published in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ClinicalTrials.govNCT04901169.

Addressing the Burden and Management Strategies for Disparities and Inequities Among Liver Transplant Professionals: The ILTS Experience.

Medical professional environments are becoming increasingly multicultural, international, and diverse in terms of its specialists. Many transplant professionals face challenges related to gender, sexual orientation or racial background in their work environment or experience inequities involving access to leadership positions, professional promotion, and compensation. These circumstances not infrequently become a major source of work-related stress and burnout for these disadvantaged, under-represented transplant professionals. In this review, we aim to 1) discuss the current perceptions regarding disparities among liver transplant providers 2) outline the burden and impact of disparities and inequities in the liver transplant workforce 3) propose potential solutions and role of professional societies to mitigate inequities and maximize inclusion within the transplant community.

Real-world implementation of normothermic machine perfusion: A detailed analysis of intraoperative and early postoperative impact.

BACKGROUND: Outcome data for the great majority of liver normothermic machine perfusion (NMP) cases derive from the strict confines of clinical trials. Detailed specifics regarding the intraoperative and early postoperative impact of NMP on reperfusion injury and its sequelae during real-world use of this emerging technology remain largely unavailable. METHODS: We analyzed transplants performed in a 3-month pilot period during which surgeons invoked commercial NMP at their discretion. Living donor, multi-organ, and hypothermic machine perfusion transplants were excluded. RESULTS: Intraoperatively, NMP (n = 24) compared to static cold storage (n = 25) recipients required less peri-reperfusion bolus epinephrine (0 vs. 60 µg; p < .001) and post-reperfusion fresh frozen plasma (2.5 vs. 7.0 units; p = .0069), platelets (.0 vs. 2.0 units; p = .042), and hemostatic agents (0% vs. 24%; p = .010). Time from incision to venous reperfusion did not differ (3.6 vs. 3.1; p = .095) but time from venous reperfusion to surgery end was shorter for NMP recipients (2.3 vs. 2.8 h; p = .0045). Postoperatively, NMP recipients required fewer red blood cell (1.0 vs. 4.0 units; p = .0083) and fresh frozen plasma (4.0 vs. 7.0 units; p = .046) transfusions, had shorter intensive care unit stays (33.5 vs. 58.4 h; p = .012), and experienced less early allograft dysfunction according to both the Model for Early Allograft Function Score (3.4 vs. 5.0; p = .0047) and peak AST within 10 days of transplant (619 vs. 1,181 U/L; p = .036). Liver acceptance for the corresponding recipient was conditional on NMP use for 63% (15/24) of cases. CONCLUSION: Real-world NMP use was associated with significantly lower intensity of reperfusion injury and intraoperative and postoperative care that may translate into patient benefit.

Lactate concentration at the end of liver transplant: Early predictor of graft function or just one piece of the puzzle?

BACKGROUND: The post-operative course after Liver Transplantation (LT) can be complicated by early allograft dysfunction (EAD), primary nonfunction (PNF) and death. A lactate concentration at the end of transplant of ≥5 mmol/L was recently proposed as a predictive marker of PNF, EAD, and mortality; this study aimed to validate these previous reports in a large single center cohort. METHODS: This retrospective cohort study included adult liver transplant recipients who received grafts from deceased donors at our center between June 2012 and May 2021. Receiver operating characteristic (ROC) curves for the lactate concentration at the end of transplantation were computed to determine the AUC for PNF, EAD and mortality at 90 days. RESULTS: In our cohort of 1137 cases, the AUCs for lactate to predict EAD, PNF and mortality were respectively .56 (95% confidence interval [CI]: .53-.60), .69 (95% CI: .52-.85), and .74 (95% CI: .63-.84). CONCLUSION: The clinical value of lactate concentration at the end of transplantation to predict PNF, EAD and mortality at 90 days was, at best, modest, as shown by the relatively low AUCs. Our findings cannot validate previous reports that the lactate level alone is a good predictor of poor outcomes after liver transplantation.

Number of Local Regional Therapies for Hepatocellular Carcinoma and Peri-Operative Outcomes after Liver Transplantation.

The wait times for patients with hepatocellular carcinoma (HCC) listed for liver transplant are longer than ever, which has led to an increased reliance on the use of pre-operative LRTs. The impact that multiple rounds of LRTs have on peri-operative outcomes following transplant is unknown. This was a retrospective single center analysis of 298 consecutive patients with HCC who underwent liver transplant (January 2017 to May 2021). The data was obtained from two institution-specific databases and the TransQIP database. Of the 298 patients, 27 (9.1%) underwent no LRTs, 156 (52.4%) underwent 1-2 LRTs, and 115 (38.6%) underwent ≥3 LRTs prior to LT. The patients with ≥3 LRTs had a significantly higher rate of bile leak compared to patients who received 1-2 LRTs (7.0 vs. 1.3%, p = 0.014). Unadjusted and adjusted regression analyses demonstrated a significant association between the total number of LRTs administered and bile leak, but not rates of overall biliary complications. The total number of LRTs was not significantly associated with any other peri-operative or post-operative outcome measure. These findings support the aggressive use of LRTs to control HCC in patients awaiting liver transplant, with further evaluation needed to confirm the biliary leak findings.

Intraoperative Use of Albumin in Major Noncardiac Surgery: Incidence, Variability, and Association With Outcomes.

BACKGROUND: The impact of albumin use during major surgery is unknown, and a dearth of evidence governing its use in major noncardiac surgery has long precluded its standardization in clinical guidelines. OBJECTIVE: In this study, we investigate institutional variation in albumin use among medical centers in the United States during major noncardiac surgery and explore the association of intraoperative albumin administration with important postoperative outcomes. METHODS: The study is an observational retrospective cohort analysis performed among 54 U.S. hospitals in the Multicenter Perioperative Outcomes Group and includes adult patients who underwent major noncardiac surgery under general anesthesia between January 2014 and June 2020. The primary endpoint was the incidence of albumin administration. Secondary endpoints are acute kidney injury (AKI), net-positive fluid balance, pulmonary complications, and 30-day mortality. Albumin-exposed and albumin-unexposed cases were compared within a propensity score-matched cohort to evaluate associations of albumin use with outcomes. RESULTS: Among 614,215 major surgeries, predominantly iso-oncotic albumin was administered in 15.3% of cases and featured significant inter-institutional variability in use patterns. Cases receiving intraoperative albumin involved patients of higher American Society of Anesthesiologists physical status and featured larger infused crystalloid volumes, greater blood loss, and vasopressor use. Overall, albumin was most often administered at high-volume surgery centers with academic affiliation, and within a propensity score-matched cohort (n=153,218), the use of albumin was associated with AKI (aOR 1.24, 95% CI 1.20-1.28, P <0.001), severe AKI (aOR 1.45, 95% CI 1.34-1.56, P <0.001), net-positive fluid balance (aOR 1.18, 95% CI 1.16-1.20, P <0.001), pulmonary complications (aOR 1.56, 95% CI 1.30-1.86, P <0.001), and 30-day all-cause mortality (aOR 1.37, 95% CI 1.26-1.49, P <0.001). CONCLUSIONS: Intravenous albumin is commonly administered among noncardiac surgeries with significant inter-institutional variability in use in the United States. Albumin administration was associated with an increased risk of postoperative complications.

Perioperative mortality in liver transplantation before and after the implementation of the organ allocation policy Share 35.

INTRODUCTION: In 2013, a new liver transplant allocation policy (Share 35) aimed to reduce waitlist-mortality was introduced in the United States. Regional organ sharing for recipients with a MELD score of ≥35 was prioritized over local allocation to those with lower MELD scores. Our aim was to assess the changes in perioperative mortality following the introduction of Share 35 as well as changes in patients' short-term 7-day survival, patients discharged alive and 1-year survival. Analyses were also carried out for the subgroups of patients with MELD scores ≥ and < 35. METHODS: We used data from the Scientific Registry of Transplant Recipients and included liver transplants between March 2002 and December 2018 in this retrospective cohort study. Perioperative mortality was defined as death during and within two days of liver transplant. We used robust interrupted time series analyses to evaluate the impact of Share 35 on mortality. RESULTS: We included 90 002 liver transplants in our analysis and observed a decreasing trend in perioperative mortality over time (-.061 deaths per 1000 cases per month, 95% CI -.084 to -.037, p < .001). Share 35 was not associated with a change in perioperative mortality (p = .33), short-term 7-day survival (p = .48), survival to discharge (p = .56), or 1-year survival (p = .27). CONCLUSIONS: Prioritizing sicker recipients with a MELD score ≥35 for liver transplantation was not associated with a change in postoperative mortality.

Gender and Racial Disparity Among Liver Transplantation Professionals: Report of a Global Survey.

Equality, diversity, and inclusion (EDI) are fundamental principles. Little is known about the pattern of practice and perceptions of EDI among liver transplant (LT) providers. International Liver Transplant Society (ILTS) EDI Committee survey around topics related to discrimination, mentorship, and gender. Answers were collected and analyzed anonymously. Worldwide female leadership was also queried via publicly available data. The survey was e-mailed to 1312 ILTS members, 199 responses (40.7% female) were collected from 38 countries (15.2% response rate). Almost half were surgeons (45.7%), 27.6% hepatologists and 26.6% anesthetists. Among 856 LT programs worldwide, 8.2% of leadership positions were held by females, and 22% of division chiefs were female across all specialties. Sixty-eight of respondents (34.7%) reported some form of discrimination during training or at their current position, presumably related to gender/sexual orientation (20.6%), race/country of origin (25.2%) and others (7.1%). Less than half (43.7%) received mentorship when discrimination occurred. An association between female responses and discrimination, differences in compensation, and job promotion was observed. This survey reveals alarmingly high rate of experience with racial and gender disparity, lack of mentorship, and very low rates of female leadership in the LT field and calls to action to equity and inclusion.

Women Leadership in Liver Transplantation-Results of an International Survey.

BACKGROUND: The International Liver Transplantation Society (ILTS) has placed a strong focus on achieving gender equality and equity in liver transplant (LT). We aimed to understand gender distribution in leadership positions among LT physicians around the world and within ILTS. METHODS: In 2019, the ILTS Equality, Diversity, and Inclusion Committee distributed a survey to obtain granular data on gender and characteristics of transplant physicians as well as those in leadership positions in each center. Additionally, data were collected on the gender composition of the ILTS membership, council, chairpersons, and committees and from the United Network for Organ Sharing. RESULTS: Data were collected from 243 transplant centers. Thirty-two (13.2%) had at least 1 woman as the director of LT, chief of transplant surgery, or chief of transplant hepatology. Of the 243 centers, 133 reported the age and gender of the leadership personnel. Women physicians comprised 152 of the 833 transplant surgeons (18.2%) and 298 of the 935 hepatologists (31.9%). Among the 1331 ILTS physician members, 588 (44.2%) provided gender information in their member profiles, and 155 (26.3%) identified themselves as women. Of the 26 ILTS leadership positions, 7 (26.9%) were held by women. CONCLUSIONS: This analysis of worldwide gender distribution in the LT physician workforce showed notable gender disparity in LT leadership around the globe and within the ILTS. These data provide a launching point for promoting and achieving gender equality and equity in LT.

Organ donor management goals and delayed graft function in adult kidney transplant recipients.

BACKGROUND: Delayed graft function (DGF) after kidney transplantation is a common occurrence and correlates with poor graft and patient outcomes. Donor characteristics and care are known to impact DGF. We attempted to show the relationship between achievement of specific donor management goals (DMG) and DGF. METHODS: This is a retrospective case-control study using data from 14 046 adult kidney donations after brain death from hospitals in 18 organ procurement organizations (OPOs) which were transplanted to adult recipients between 2012 and 2018. Data on DMG compliance and donor, recipient, and ischemia-related factors were used to create multivariable logistic regression models. RESULTS: The overall rate of DGF was 29.4%. Meeting DMGs for urine output and vasopressor use were associated with decreased risk of DGF. Sensitivity analyses performed with different imputation methods, omitting recipient factors, and analyzing multiple time points yielded largely consistent results. CONCLUSIONS: The development of DMGs continues to show promise in improving outcomes in the kidney transplant recipient population. Studies have already shown increased kidney utilization in smaller cohorts, as well as other organs, and shown decreased rates of DGF. Additional research and analysis are required to assess interactions between meeting DMGs and correlation versus causality in DMGs and DGF.

Expedited evaluation for liver transplantation: A critical look at processes and outcomes.

BACKGROUND: Most patients are listed for liver transplant (LT) following extensive workup as outpatients ("conventional evaluation"). Some patients undergo urgent evaluation as inpatients after being transferred to a transplant center ("expedited evaluation"). We hypothesized that expedited patients would have inferior survival due to disease severity at the time of transplant and shorter workup time. METHODS: Patients who underwent evaluation for LT at our institution between 2012 and 2016 were retrospectively reviewed. The expedited and conventional cohorts were defined as above. Living donor LT recipients, combined liver-kidney recipients, acute liver failure patients, and re-transplant patients were excluded. We compared patient characteristics and overall survival between patients who received a transplant following expedited evaluation and those who did not, and between LT recipients based on expedited or conventional evaluation. RESULTS: Five-hundred and nine patients were included (110 expedited, 399 conventional). There was no difference in graft or patient survival at 1 year for expedited versus conventional LT recipients. In multivariable analysis of overall survival, only Donor Risk Index (HR 1.97, CI 1.04-3.73, P = .037, per unit increase) was associated with increased risk of death. CONCLUSIONS: Patients who underwent expedited evaluation for LT had significant demographic and clinical differences from patients who underwent conventional evaluation, but comparable post-transplant survival.

Monitoring of Enoxaparin during Hemodialysis Covered by Regional Citrate Anticoagulation in Acute Kidney Injury: A Prospective Cohort Study.

BACKGROUND: Current guidelines recommend the monitoring of anti-factor Xa (anti-Xa) levels to avoid an accumulation of low-molecular-weight heparins in patients with acute kidney injury, but there is no evidence on how to proceed with such monitoring during continuous renal replacement therapy. Against this background, we investigated the potential accumulation of enoxaparin administered subcutaneously for venous thromboembolism prophylaxis in critically ill patients during continuous renal replacement therapy covered by regional citrate anticoagulation. METHODS: Anti-Xa levels were measured at baseline (≤12 h before renal replacement therapy) and on three consecutive days (A to C) when enoxaparin had reached trough levels. Supplementary testing included modified assays of rotational thromboelastometry known to be highly sensitive for low-molecular-weight heparins. RESULTS: The 16 men and 13 women included were adults comparable in age, body mass index, thromboembolism risk assessment, and clinical severity of the disease. Throughout the four examinations, the median trough levels of anti-Xa remained below the detection limit of the test (<0.1 IU mL-1), with interquartile ranges of <0.1 to 0.14 IU mL-1 at baseline and <0.1 to 0.16 IU mL-1 on days A/B/C. All rotational thromboelastometry parameters of clot initiation and clot formation dynamics did not significantly change from baseline to day C. CONCLUSIONS: Neither anti-Xa levels nor modified assays of rotational thromboelastometry revealed any accumulation of enoxaparin administered for thromboprophylaxis during continuous renal replacement therapy covered by regional citrate anticoagulation. Although generally recommended in patients with acute kidney injury, monitoring of anti-Xa levels should be questioned in this defined setting.

Machine Learning Prediction of Liver Allograft Utilization From Deceased Organ Donors Using the National Donor Management Goals Registry.

Early prediction of whether a liver allograft will be utilized for transplantation may allow better resource deployment during donor management and improve organ allocation. The national donor management goals (DMG) registry contains critical care data collected during donor management. We developed a machine learning model to predict transplantation of a liver graft based on data from the DMG registry. METHODS: Several machine learning classifiers were trained to predict transplantation of a liver graft. We utilized 127 variables available in the DMG dataset. We included data from potential deceased organ donors between April 2012 and January 2019. The outcome was defined as liver recovery for transplantation in the operating room. The prediction was made based on data available 12-18 h after the time of authorization for transplantation. The data were randomly separated into training (60%), validation (20%), and test sets (20%). We compared the performance of our models to the Liver Discard Risk Index. RESULTS: Of 13 629 donors in the dataset, 9255 (68%) livers were recovered and transplanted, 1519 recovered but used for research or discarded, 2855 were not recovered. The optimized gradient boosting machine classifier achieved an area under the curve of the receiver operator characteristic of 0.84 on the test set, outperforming all other classifiers. CONCLUSIONS: This model predicts successful liver recovery for transplantation in the operating room, using data available early during donor management. It performs favorably when compared to existing models. It may provide real-time decision support during organ donor management and transplant logistics.

"The use of bilateral continuous erector spinae plane blocks for postoperative analgesia after right-sided living donor hepatectomy: A feasibility study".

BACKGROUND: Postoperative pain after living donor hepatectomy is significant. Postoperative coagulopathy may limit the use of epidural analgesia, the gold standard for pain control in abdominal surgery. The erector spinae plane block (ESPB) is a novel regional anesthesia technique that has been shown to provide effective analgesia in abdominal surgery. In this study, we examined the effect of continuous ESPB, administered via catheters, on perioperative opioid requirements after right living donor hepatectomies for liver transplantation. METHODS: We performed a retrospective cohort study in patients undergoing right living donor hepatectomy. Twenty-four patients who received preoperative ESPB were compared to 51 historical controls who did not receive regional anesthesia. The primary endpoint was the total amount of oral morphine equivalents (OMEs) required on the day of surgery and postoperative day (POD) 1. RESULTS: Patients in the ESPB group required a lower total amount of OMEs on the day of surgery and POD 1 [141 (107-188) mg] compared the control group [293 (220-380) mg; P < .001]. CONCLUSIONS: The use of continuous ESPB significantly reduced opioid consumption following right living donor hepatectomy.

Advantages and Limitations of Clinical Scores for Donation After Circulatory Death Liver Transplantation.

Background: Scoring systems have been proposed to select donation after circulatory death (DCD) donors and recipients for liver transplantation (LT). We hypothesized that complex scoring systems derived in large datasets might not predict outcomes locally. Methods: Based on 1-year DCD-LT graft survival predictors in multivariate logistic regression models, we designed, validated, and compared a simple index using the University of California, San Francisco (UCSF) cohort (n = 136) and a universal-comprehensive (UC)-DCD score using the United Network for Organ Sharing (UNOS) cohort (n = 5,792) to previously published DCD scoring systems. Results: The total warm ischemia time (WIT)-index included donor WIT (dWIT) and hepatectomy time (dHep). The UC-DCD score included dWIT, dHep, recipient on mechanical ventilation, transjugular-intrahepatic-portosystemic-shunt, cause of liver disease, model for end-stage liver disease, body mass index, donor/recipient age, and cold ischemia time. In the UNOS cohort, the UC-score outperformed all previously published scores in predicting DCD-LT graft survival (AUC: 0.635 vs. ≤0.562). In the UCSF cohort, the total WIT index successfully stratified survival and biliary complications, whereas other scores did not. Conclusion: DCD risk scores generated in large cohorts provide general guidance for safe recipient/donor selection, but they must be tailored based on non-/partially-modifiable local circumstances to expand DCD utilization.

Longer Distance From Dialysis Facility to Transplant Center Is Associated With Lower Access to Kidney Transplantation.

Rates of kidney transplantation vary substantially across dialysis facilities in the United States. Whether distance between the dialysis facility and transplant center associates with variations in transplantation rates has not been examined. METHODS: We performed a retrospective study of adults treated with dialysis between 2005 and 2015, according to the US Renal Data System. We examined the association between distance from dialysis facility to transplant center and time to kidney transplantation (primary outcome) and waitlist registration (secondary outcome) using Fine-Gray models. We also performed sensitivity analyses using the distance from each patient's dialysis facility to the nearest transplant center as the predictor so that patients who were never registered on the waitlist (and therefore would not have a transplant center) could be included. RESULTS: In total, 178 885 waitlisted patients were included for our primary analysis. As distance between dialysis facility and transplant center increased, lower hazard of transplantation (subhazard ratio [HR], 0.92; 95% confidence interval [CI], 0.91-0.94, if distance was 10 to <50 miles; sub-HR, 0.90; 95% CI, 0.88-0.92, if distance ≥50 miles compared with <10 miles) was noted. We also found a weak association between longer distance and hazard of waitlist registration (sub-HR, 0.96; 95% CI, 0.94-0.97, if distance was ≥50 miles versus <10 miles). Findings were similar in sensitivity analyses using distance between dialysis facility and the nearest transplant center (N = 1 149 721). CONCLUSIONS: Patients receiving dialysis in facilities located further away from transplant centers have lower hazard of kidney transplantation. Developing strategies to address barriers to transplantation in patients receiving dialysis at facilities located far away from a transplant center may help improve disparities in transplantation rates.

COVID-19 and Abdominal Transplant: A Stepwise Approach to Practice During Pandemic Conditions.

BACKGROUND: The novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) disease has transformed innumerable aspects of medical practice, particularly in the field of transplantation. MAIN BODY: Here we describe a single-center approach to creating a generalizable, comprehensive, and graduated set of recommendations to respond in stepwise fashion to the challenges posed by these conditions, and the underlying principles guiding such decisions. CONCLUSIONS: Creation of a stepwise plan will allow transplant centers to respond in a dynamic fashion to the ongoing challenges posed by the COVID-19 pandemic.

The Association Between Vena Cava Implantation Technique and Acute Kidney Injury After Liver Transplantation.

BACKGROUND: Acute kidney injury (AKI) after liver transplantation is associated with increased morbidity and mortality. It remains controversial whether the choice of vena cava reconstruction technique impacts AKI. METHODS: This is a single-center retrospective cohort of 897 liver transplants performed between June 2009 and September 2018 using either the vena cava preserving piggyback technique or caval replacement technique without veno-venous bypass or shunts. The association between vena cava reconstruction technique and stage of postoperative AKI was assessed using multivariable ordinal logistic regression. Causal mediation analysis was used to evaluate warm ischemia time as a potential mediator of this association. RESULTS: The incidence of AKI (AKI stage ≥2) within 48 h after transplant was lower in the piggyback group (40.3%) compared to the caval replacement group (51.8%, P < 0.001). Piggyback technique was associated with a reduced risk of developing a higher stage of postoperative AKI (odds ratio, 0.49; 95% confidence interval, 0.37-0.65, P < 0.001). Warm ischemia time was shorter in the piggyback group and identified as potential mediator of this effect. There was no difference in renal function (estimated glomerular filtration rate and the number of patients alive without dialysis) 1 y after transplant. CONCLUSIONS: Piggyback technique, compared with caval replacement, was associated with a reduced incidence of AKI after liver transplantation. There was no difference in long-term renal outcomes between the 2 groups.