Utility of preoperative troponin I to predict mortality in adult liver transplant recipients: Revisiting pretransplant cardiac risk in the current MELD-allocation era.

BACKGROUND: Preoperative risk assessment in liver transplant (LT) candidates, particularly related to cardiac risk, is an area of intense interest for transplant clinicians. Various cardiac testing methods are employed by transplant centers to characterize cardiac risk. Serum troponin is an established method for the detection of myocardial injury in a wide variety of clinical settings. Preoperative troponin screening has been reported to predict postoperative cardiac events and mortality in various surgical patient populations, however, the utility of preoperative troponin to predict posttransplant outcomes in current LT candidate populations requires further investigation. METHODS: We performed a prospective blinded study in a cohort of 275 consecutive LT recipients at a single transplant center to determine if preoperative serum troponin I (TnI) was predictive for postoperative 1-year mortality. RESULTS: Abnormal preoperative TnI levels (>.1 ng/mL) were found in 38 patients (14%). One-year mortality occurred in 19 patients (7%). There was no significant difference in mortality between patients with normal and abnormal troponin levels. Additionally, we found that there was no significant difference in early postoperative major adverse cardiac events between patient groups. CONCLUSIONS: Contrary to previous reports, elevated preoperative TnI was not significantly predictive of posttransplant mortality in LT recipients at our institution.

The Evolution of Redo Liver Transplantation Over 35 Years: Analysis of 654 Consecutive Adult Liver Retransplants at a Single Center.

OBJECTIVE: To examine liver retransplantation (ReLT) over 35 years at a single center. BACKGROUND: Despite the durability of liver transplantation (LT), graft failure affects up to 40% of LT recipients. METHODS: All adult ReLTs from 1984 to 2021 were analyzed. Comparisons were made between ReLTs in the pre versus post-model for end-stage liver disease (MELD) eras and between ReLTs and primary-LTs in the modern era. Multivariate analysis was used for prognostic modeling. RESULTS: Six hundred fifty-four ReLTs were performed in 590 recipients. There were 372 pre-MELD ReLTs and 282 post-MELD ReLTs. Of the ReLT recipients, 89% had one previous LT, whereas 11% had ≥2. Primary nonfunction was the most common indication in the pre-MELD era (33%) versus recurrent disease (24%) in the post-MELD era. Post-MELD ReLT recipients were older (53 vs 48, P = 0.001), had higher MELD scores (35 vs 31, P = 0.01), and had more comorbidities. However, post-MELD ReLT patients had superior 1, 5, and 10-year survival compared with pre-MELD ReLT (75%, 60%, and 43% vs 53%, 43%, and 35%, respectively, P < 0.001) and lower in-hospital mortality and rejection rates. Notably, in the post-MELD era, the MELD score did not affect survival. We identified the following risk factors for early mortality (≤12 months after ReLT): coronary artery disease, obesity, ventilatory support, older recipient age, and longer pre-ReLT hospital stay. CONCLUSIONS: This represents the largest single-center ReLT report to date. Despite the increased acuity and complexity of ReLT patients, post-MELD era outcomes have improved. With careful patient selection, these results support the efficacy and survival benefit of ReLT in an acuity-based allocation environment.

Super-massive transfusion during liver transplantation.

BACKGROUND: Massive hemorrhage and transfusion during liver transplantation (LT) present great challenges. We aimed to investigate the incidence and risk factors for super-massive transfusion (SMT) and survival outcome and factors that negatively affect survival in patients who received SMT during LT. STUDY DESIGN AND METHODS: We included adult patients undergoing LT from 2004 to 2019. SMT was defined as transfusion of ≥50 units of red blood cells (RBC) during LT. Independent risk factors were identified by multivariable logistic regression. Ninety-day survival was recorded and factors that negatively affected survival were analyzed by the Cox survival test. RESULTS: Of 2772 patients, 158 (5.6%) received SMT during LT. Mean RBC transfusion was 72.6 (±23.4) units with a maximum of 168 units. Four variables (MELD-Na score, previous upper abdominal surgery, portal vein thrombosis, and remote retransplant) were independent risk factors for SMT (odds ratio 1.800-8.274, 95% CI 1.008-16.685, all p < .005). The 90-day survival rate in SMT patients was 81.6%. Preoperative pulmonary hypertension and massive postreperfusion transfusion negatively affected 90-day survival (hazard ratio 2.658-4.633, 95% CI 1.144-10.130, and all p < .05). CONCLUSIONS: In this large retrospective study, we found that SMT occurred in a small percentage of patients and was associated with relatively satisfactory short-term survival. Identification of preoperative risk factors for SMT and factors that negatively affect survival improve our understanding of this unique LT patient population.

Optimal anesthetic conduct regarding immediate and short-term outcomes after liver transplantation - Systematic review of the literature and expert panel recommendations.

BACKGROUND: In the era of enhanced recovery after surgery, there is significant discussion regarding the impact of intraoperative anesthetic management on short-term outcomes following liver transplantation (LT), with no clear consensus in the literature. OBJECTIVES: To identify whether or not intraoperative anesthetic management affects short-term outcomes after liver transplantation. DATA SOURCES: Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central. METHODS: A systematic review following PRISMA guidelines was undertaken. The systematic review was registered on PROSPERO (CRD42021239758). An international expert panel made recommendations for clinical practice using the GRADE approach. RESULTS: After screening, 14 studies were eligible for inclusion in this systematic review. Six were prospective randomized clinical trials, three were prospective nonrandomized clinical trials, and five were retrospective studies. These manuscripts were reviewed to look at five questions regarding anesthetic care and its impact on short term outcomes following liver transplant. After review of the literature, the quality of evidence according to the following outcomes was as follows: intraoperative and postoperative morbidity and mortality (low), early allograft dysfunction (low), and hospital and ICU length of stay (moderate). CONCLUSIONS: For optimal short term outcomes after liver transplantation, the panel recommends the use of volatile anesthetics in preference to total intravenous anesthesia (TIVA) (Level of Evidence: Very low; Strength of Recommendation: Weak) and minimum alveolar concentration (MAC) versus bispectral index (BIS) for depth of anesthesia monitoring (Level of Evidence: Very low; Strength of Recommendation: Weak). Regarding ventilation and oxygenation, the panel recommends a restrictive oxygenation strategy targeting a PaO2 of 70-120 mmHg (10-14 kPa), a tidal volume of 6-8 ml/kg ideal body weight (IBW), administration of positive end expiratory pressure (PEEP) tailored to patient intraoperative physiology, and recruitment maneuvers. (Level of evidence: Very low; Strength of Recommendation: Strong). Finally, the panel recommends the routine use of antiemetic prophylaxis. (Level of evidence: low; Strength of Recommendation: Strong).

Takotsubo syndrome after liver transplantation: An association with intraoperatively administered epinephrine and fentanyl.

Takotsubo syndrome (TTS) can develop after liver transplant (LT), but its predisposing factors are poorly understood. In this study, we aimed to determine if perioperative factors were associated with posttransplant TTS. Adult patients who underwent primary LT between 2006 and 2018 were included. Patients with and without TTS were identified and matched by propensity scores. Of 2181 LT patients, 38 developed postoperative TTS with a mean left ventricular ejection fraction of 25.5% (±7.8%). Multivariable logistic regression revealed two preoperative risk factors (alcoholic cirrhosis and model for end-stage liver disease-sodium scores) for TTS. Post-propensity match analyses showed that TTS patients had significantly higher doses of epinephrine and lower doses of fentanyl during LT compared with non-TTS patients. A higher dose of epinephrine and a lower dose of fentanyl was associated with a higher predicted probability of TTS. All TTS patients had full recovery of cardiac function and had comparable 1-year survival. In conclusion, TTS occurred at a rate of 1.7% after LT and was associated with two pretransplant risk factors. The higher doses of epinephrine and lower doses of fentanyl administered during LT were associated with posttransplant TTS. More studies on the relationship between intraoperative medications and TTS are warranted.

Combined Cardiothoracic Surgery and Liver Transplantation Versus Isolated Liver Transplantation.

OBJECTIVE: Combined cardiothoracic surgery and liver transplantation (cCSLT) recently increasingly has been used. Despite that, liver transplant immediately after cardiothoracic surgery has not been well-characterized. The authors aimed to compare perioperative management and postoperative outcomes between patients undergoing cCSLT and isolated liver transplantation (iLT). DESIGN: A retrospective study. SETTING: University tertiary medical center. PARTICIPANTS: Twenty-five cCSLT patients and 1091 iLT patients at a single institution from 2010 to 2017. INTERVENTIONS: Twenty-five cCSLT patients were compared with 100 randomly selected and 100 propensity-matched iLT patients. MEASUREMENTS AND MAIN RESULTS: All cCSLT patients underwent comprehensive preoperative evaluation by a multidisciplinary team. Of 25 cardiothoracic surgeries, heart transplant (n = 9) was most common, followed by coronary artery bypass grafting (n = 5) and lung transplant (n = 3). Intraoperative management of cCSLT was provided by 2 separate teams, one for cardiothoracic surgery and one for liver transplantation. Patients undergoing cCSLT often required cardiopulmonary bypass, an intra-aortic balloon pump, extracorporeal membrane oxygenation, or cardiac pharmacologic therapies and, additionally, needed more interventions including antifibrinolytic administration, venovenous bypass, massive blood transfusion, and platelet transfusions compared with iLT patients. Ninety-day survival rates were similar in the cCSLT (100%) and iLT groups (random iLT 87% and matched iLT 93%, log-rank test p = 0.089). CONCLUSIONS: Despite having end-stage liver disease and advanced cardiothoracic disorders and experiencing a complex intraoperative course, cCSLT patients had comparable 90-day survival to iLT patients. Comprehensive planning before transplant, optimal patient/donor selection, the multiple-team model, and meticulous intraoperative management are critical to the success of cCSLT.

Perioperative Considerations in Liver Transplantation.

Liver transplantation (LT) has the potential to cure patients with acute and chronic liver failure as well as a number of hepatic and biliary malignancies. Over time, due to the increasing demand for organs as well as improvements in the survival of LT recipients, patients awaiting LT have become sicker, and often undergo the procedure while critically ill. This trend has made the process of preoperative assessment and planning, intraoperative management, and postoperative management even more crucial to the success of LT programs. Multidisciplinary and specialized teams are essential and include anesthesiologists, surgeons, and intensivists. This article focuses on the preoperative evaluation, intraoperative care, and postoperative management of the liver transplant patient. Management relevant to the critically ill patient is discussed, with a focus on the management of postoperative cardiopulmonary conditions including the care of special populations such as those with hepatopulmonary syndrome and portopulmonary hypertension.

Myocardial injury in patients with hemodynamic derangements during and/or after liver transplantation.

Myocardial injury, defined as an elevation of cardiac troponin (cTn) resulting from ischemia, is associated with substantial mortality in surgical patients, and its incidence, risk factors, and impact on patients undergoing liver transplantation (LT) are poorly understood. In this study, adult patients who experienced perioperative hemodynamic derangements and had cTn measurements within 30 days after LT between 2006 and 2013 were studied. Of 502 patients, 203 (40.4%) met the diagnostic criteria (cTn I ≥0.1 ng/mL) of myocardial injury. The majority of myocardial injury occurred within the first three postoperative days and presented without clinical signs or symptoms of myocardial infarction. Thirty-day mortality in patients with myocardial injury was 11.4%, significantly higher compared with that in patients without myocardial injury (3.4%, P<.01). Cox analysis indicated the peak cTn was significantly associated with 30-day mortality. Multivariable logistic analysis identified three independent risk factors: requirement of ventilation before transplant (odds ratios (OR) 1.6, P=.006), RBC≥15 units (OR 1.7, P=.006), and the presence of PRS (OR 2.0, P=.028). We concluded that post-LT myocardial injury in this high-risk population was common and associated with mortality. Our findings may be used in pretransplant stratification. Further studies to investigate this postoperative cardiac complication in all LT patients are warranted.

Intrahepatic Transcriptomics Differentiate Advanced Fibrosis and Clinical Outcomes in Adults With Fontan Circulation.

BACKGROUND: The molecular mechanisms underlying Fontan-associated liver disease (FALD) remain largely unknown. OBJECTIVES: This study aimed to assess intrahepatic transcriptomic differences among patients with FALD according to the degree of liver fibrosis and clinical outcomes. METHODS: This retrospective cohort study included adults with the Fontan circulation. Baseline clinical, laboratory, imaging, and hemodynamic data as well as a composite clinical outcome (CCO) were extracted from medical records. Patients were classified into early or advanced fibrosis. RNA was isolated from formalin-fixed paraffin-embedded liver biopsy samples; RNA libraries were constructed with the use of an rRNA depletion method and sequenced on an Illumina Novaseq 6000. Differential gene expression and gene ontology analyses were performed with the use of DESeq2 and Metascape. RESULTS: A total of 106 patients (48% male, median age 31 years [IQR: 11.3 years]) were included. Those with advanced fibrosis had higher B-type natriuretic peptide levels and Fontan, mean pulmonary artery, and capillary wedge pressures. The CCO was present in 23 patients (22%) and was not predicted by advanced liver fibrosis, right ventricular morphology, presence of aortopulmonary collaterals, or Fontan pressures on multivariable analysis. Samples with advanced fibrosis had 228 upregulated genes compared with early fibrosis. Samples with the CCO had 894 upregulated genes compared with those without the CCO. A total of 136 upregulated genes were identified in both comparisons and were enriched in cellular response to cytokine stimulus or oxidative stress, VEGFA-VEGFR2 signaling pathway, TGF-ß signaling pathway, and vasculature development. CONCLUSIONS: Patients with FALD and advanced fibrosis or the CCO exhibited upregulated genes related to inflammation, congestion, and angiogenesis.

International Liver Transplantation Society/Society for Advancement of Transplant Anesthesia Consensus Statement on Essential Attributes of a Liver Transplant Anesthesiologist.

BACKGROUND: We sought to establish consensus on the essential skills, knowledge, and attributes that a liver transplant (LT) anesthesiologist should possess in a bid to help guide the further training process. METHODS: Consensus was achieved via a modified Delphi methodology, surveying 15 identified international experts in the fields of LT anesthesia and critical care. RESULTS: Key competencies were identified in preoperative management and optimization of a potential LT recipient; intraoperative management, including hemodynamic monitoring; coagulation and potential crisis management; and postoperative intensive and enhanced recovery care. CONCLUSIONS: This article provides an essential guide to competency-based training of an LT anesthesiologist.

Intrahepatic transcriptomics differentiate advanced fibrosis and clinical outcomes in adults with the Fontan circulation.

Background: The molecular mechanisms underlying Fontan associated liver disease (FALD) remain largely unknown. We aimed to assess intrahepatic transcriptomic differences among patients with FALD according to the degree of liver fibrosis and clinical outcomes. Methods: This retrospective cohort study included adults with the Fontan circulation at the Ahmanson/UCLA Adult Congenital Heart Disease Center. Clinical, laboratory, imaging and hemodynamic data prior to the liver biopsy were extracted from medical records. Patients were classified into early (F1-F2) or advanced fibrosis (F3-F4). RNA was isolated from formalin-fixed paraffin embedded liver biopsy samples; RNA libraries were constructed using rRNA depletion method and sequencing was performed on Illumina Novaseq 6000. Differential gene expression and gene ontology analyses were carried out using DESeq2 and Metascape. Medical records were comprehensively reviewed for a composite clinical outcome which included decompensated cirrhosis, hepatocellular carcinoma, liver transplantation, protein-losing enteropathy, chronic kidney disease stage 4 or higher, or death. Results: Patients with advanced fibrosis had higher serum BNP levels and Fontan, mean pulmonary artery and capillary wedge pressures. The composite clinical outcome was present in 23 patients (22%) and was predicted by age at Fontan, right ventricular morphology and presence of aortopulmonary collaterals on multivariable analysis. Samples with advanced fibrosis had 228 up-regulated genes compared to early fibrosis. Samples with the composite clinical outcome had 894 up-regulated genes compared to those without it. A total of 136 up-regulated genes were identified in both comparisons and these genes were enriched in cellular response to cytokine stimulus, response to oxidative stress, VEGFA-VEGFR2 signaling pathway, TGF-beta signaling pathway, and vasculature development. Conclusions: Patients with FALD and advanced liver fibrosis or the composite clinical outcome exhibit up-regulated genes including pathways related to inflammation, congestion, and angiogenesis. This adds further insight into FALD pathophysiology.

Intraoperative High Tidal Volume Ventilation and Postoperative Acute Respiratory Distress Syndrome in Liver Transplant.

BACKGROUND: Mechanical ventilation plays an important role in perioperative management and patient outcomes. Although mechanical ventilation with high tidal volume (HTV) is injurious in patients in the intensive care unit, the effects of HTV ventilation in patients undergoing liver transplant (LT) has not been reported. The aim of this study was to determine if intraoperative HTV ventilation was associated with the development of acute respiratory distress syndrome (ARDS). METHODS: Patients undergoing LT between 2013 and 2018 at a tertiary medical center were reviewed. The tidal volume was recorded at 3 time points: after anesthesia induction, before liver reperfusion, and at the end of surgery. Patients were divided into 2 groups: HTV (>10 mL/kg predicted body weight [pBW]) and non-HTV (≤10 mL/kg pBW). The 2 groups were compared. Independent risk factors were identified by multivariable logistic models. RESULTS: Of 780 LT patients, 85 (10.9%) received HTV ventilation. Female sex and greater difference between actual body weight and pBW were independent risk factors for HTV ventilation. Patients who received HTV ventilation had a significantly higher incidence of ARDS (10.3% vs 3.9%; P = .01) than those who received non-HTV ventilation. CONCLUSIONS: In this retrospective study, we showed that HTV ventilation during LT was common and was associated with a higher incidence of ARDS. Therefore, tidal volume should be carefully selected during LT surgery. More studies using a prospective randomized controlled design are needed.

Intraoperative Hypotension and 30-D Mortality After Liver Transplantation.

Intraoperative hypotension (IOH) is common and associated with mortality in major surgery. Although patients undergoing liver transplantation (LT) have low baseline blood pressure, the relation between blood pressure and mortality in LT is not well studied. We aimed to determine mean arterial pressure (MAP) that was associated with 30-d mortality in LT. Methods: We performed a retrospective cohort study. The data included patient demographics, pertinent preoperative and intraoperative variables, and MAP using various metrics and thresholds. The endpoint was 30-d mortality after LT. Results: One thousand one hundred seventy-eight patients from 2013 to 2020 were included. A majority of patients were exposed to IOH and many for a long period. Eighty-nine patients (7.6%) died within 30 d after LT. The unadjusted analysis showed that predicted mortality was associated with MAP <45 to 60 mm Hg but not MAP <65 mm Hg. The association between MAP and mortality was further tested using adjustment and various duration cutoffs. After adjustment, the shortest durations for MAPs <45, 50, and 55 mm Hg associated with 30-d mortality were 6, 10, and 25 min (odds ratio, 1.911, 1.812, and 1.772; 95% confidence interval, 1.100-3.320, 1.039-3.158, and 1.008-3.114; P = 0.002, 0.036, and 0.047), respectively. Exposure to MAP <60 mm Hg up to 120 min was not associated with increased mortality. Conclusion: In this large retrospective study, we found IOH was common during LT. Intraoperative MAP <55 mm Hg was associated with increased 30-d mortality after LT, and the duration associated with postoperative mortality was shorter with lower MAP than with higher MAP.

Applications and Outcomes of Extracorporeal Life Support Use in Adult Liver Transplantation: A Case Series and Review of Literature.

The use of extracorporeal life support (ECLS) is increasingly reported in adult liver transplantation (LT). However, neither the role of ECLS in the perioperative setting for LT nor its outcomes has been well defined. We performed a retrospective chart review of all adult LT patients at our institution who received ECLS from 2004 to 2021. We also conducted a comprehensive literature search for adult LT cases that involved perioperative ECLS for respiratory or cardiac failure. Over the study period, 11 LT patients required ECLS at our institution, two for respiratory and nine for cardiac failure. Both patients with respiratory failure received ECLS as a bridge to LT and survived to discharge. Nine patients required ECLS for acute cardiac failure either intraoperatively or postoperatively, and two survived to discharge. In the literature, we identified 35 cases of respiratory failure in LT patients requiring perioperative ECLS. Applications included preoperative bridge to LT (n = 6) and postoperative rescue (n = 29), for which overall survival was 44%. We identified 31 cases of cardiac failure in LT patients requiring either ECLS or cardiopulmonary bypass for cardiac support or rescue for intraoperative or postoperative cardiac failure (n = 30). There is evidence for consideration of ECLS as a bridge to LT in patients with potentially reversible respiratory failure or as rescue therapy for respiratory failure in posttransplant patients. ECLS has a prohibitively high risk of futility in pretransplant patients with cardiac failure but may have a role in LT patients with a functioning graft and potentially reversible cardiac failure.

Major Thromboembolic Complications in Liver Transplantation: The Role of Rotational Thromboelastometry and Cryoprecipitate Transfusion.

BACKGROUND: Although hemorrhage is a major concern during liver transplantation (LT), the risk for thromboembolism is well recognized. Implementation of rotational thromboelastometry (ROTEM) has been associated with the increased use of cryoprecipitate; however, the role of ROTEM-guided transfusion strategy and cryoprecipitate administration in the development of major thromboembolic complications (MTCs) has never been documented. METHODS: We conducted a study on patients undergoing LT before and after the implementation of ROTEM. We defined MTC as intracardiac thrombus, pulmonary embolism, hepatic artery thrombosis, and ischemic stroke in 30 d after LT. We used a propensity score to match patients during the 2 study periods. RESULTS: Among 2330 patients, 119 (4.9%) developed MTC. The implementation of ROTEM was significantly associated with an increase in cryoprecipitate use (1.1 ± 1.1 versus 2.9 ± 2.3 units, P < 0.001) and MTC (4.2% versus 9.5%, P < 0.001). Further analysis demonstrated that the use of cryoprecipitate was an independent risk factor for MTC (odds ratio 1.1, 95% confidence interval 1.04-1.24, P = 0.003). Patients with MTC had significantly lower 1-y survival. CONCLUSIONS: Our study suggests that the implementation of ROTEM and the use of cryoprecipitate play significant roles in the development of MTC in LT. The benefits and risks of cryoprecipitate transfusion should be carefully evaluated before administration.

Hemodynamic Instability During Liver Transplantation in Patients With End-stage Liver Disease: A Consensus Document from ILTS, LICAGE, and SATA.

Hemodynamic instability (HDI) during liver transplantation (LT) can be difficult to manage and increases postoperative morbidity and mortality. In addition to surgical causes of HDI, patient- and graft-related factors are also important. Nitric oxide-mediated vasodilatation is a common denominator associated with end-stage liver disease related to HDI. Despite intense investigation, optimal management strategies remain elusive. In this consensus article, experts from the International Liver Transplantation Society, the Liver Intensive Care Group of Europe, and the Society for the Advancement of Transplant Anesthesia performed a rigorous review of the most current literature regarding the epidemiology, causes, and management of HDI during LT. Special attention has been paid to unique LT-associated conditions including the causes and management of vasoplegic syndrome, cardiomyopathies, LT-related arrhythmias, right and left ventricular dysfunction, and the specifics of medical and fluid management in end-stage liver disease as well as problems specifically related to portal circulation. When possible, management recommendations are made.

Orthotopic Heart and Combined Heart Liver Transplantation: the Ultimate Treatment Option for Failing Fontan Physiology.

Purpose of the Review: This is a comprehensive update on failing Fontan physiology and the role of heart and combined heart and liver transplantation in the current era. Recent Findings: Single ventricle physiology encompasses a series of rare congenital cardiac abnormalities that are characterized by absence of or hypoplasia of one ventricle. This effectively results in a single ventricular pumping chamber. These abnormalities are rarely compatible with long-term survival if left without surgical palliation in the first few years of life. Surgical treatment of single ventricle physiology has evolved over the past 60 years and is characterized by numerous creative innovations. These include the development of arteriopulmonary shunts, the evolution of partial cavopulmonary connections, and the eventual development of the "Fontan" operation. Regardless of the type of Fontan modification, the long-term consequences of the Fontan operation are predominantly related to chronic central venous hypertension and the multi-organ consequences thereof. Atrial arrhythmias can further compromise this circulation.Patients with single ventricle physiology represent a special sub-segment of congenital cardiac transplants and are arguably the most challenging patients considered for transplantation. Summary: This review describes in detail the challenges and opportunities of heart and liver transplantation in Fontan patients, as viewed and managed by the experienced team at the Ahmanson/UCLA Adult Congenital Heart Center.

Incidental intracardiac thromboemboli during liver transplantation: incidence, risk factors, and management.

Even though numerous cases of massive thromboemboli have been reported in the literature, intracardiac thromboemboli (ICTs) incidentally found during orthotopic liver transplantation (OLT) have not been examined. In this study, we retrospectively examined the incidence, risk factors, and management of incidental ICTs during OLT. After institutional review board approval, adult patients who underwent OLT between January 2004 and December 2008 at our center were reviewed. ICTs were identified and confirmed by the examination of OLT datasheets, anesthesia records, and recorded transesophageal echocardiography (TEE) clips. The clinical presentation, management, and outcomes of the patients with ICTs were reviewed. Risk factors were analyzed by multivariate logistic regression. During the study period, 426 of the 936 adult OLT patients (45.5%) underwent intraoperative TEE monitoring. Incidental ICTs were identified in 8 of these 426 patients (1.9%). Two ICTs occurred before reperfusion, and 6 ICTs occurred after reperfusion. The treatment was at the discretion of the treating physicians; however, none of the patients received an anticoagulant or thrombolytics. Multivariate analysis identified 2 independent risk factors for intraoperative incidental ICTs: the presence of symptomatic or surgically treated portal hypertension (a history of gastrointestinal bleeding, a transjugular intrahepatic portosystemic shunt procedure, or portocaval shunt surgery) before OLT and intraoperative hemodialysis (odds ratios of 4.05 and 7.29, respectively; P < 0.05 for both). In conclusion, incidental ICTs during OLT occurred at a rate of 1.9% and were associated with several preoperative and intraoperative risk factors. The use of TEE allows early identification, which may be important. Our management for incidental ICTs is described; however, no conclusions can be made about the optimal therapy.

Training and Validation of Deep Neural Networks for the Prediction of 90-Day Post-Liver Transplant Mortality Using UNOS Registry Data.

Prediction models of post-liver transplant mortality are crucial so that donor organs are not allocated to recipients with unreasonably high probabilities of mortality. Machine learning algorithms, particularly deep neural networks (DNNs), can often achieve higher predictive performance than conventional models. In this study, we trained a DNN to predict 90-day post-transplant mortality using preoperative variables and compared the performance to that of the Survival Outcomes Following Liver Transplantation (SOFT) and Balance of Risk (BAR) scores, using United Network of Organ Sharing data on adult patients who received a deceased donor liver transplant between 2005 and 2015 (n = 57,544). The DNN was trained using 202 features, and the best DNN's architecture consisted of 5 hidden layers with 110 neurons each. The area under the receiver operating characteristics curve (AUC) of the best DNN model was 0.703 (95% CI: 0.682-0.726) as compared to 0.655 (95% CI: 0.633-0.678) and 0.688 (95% CI: 0.667-0.711) for the BAR score and SOFT score, respectively. In conclusion, despite the complexity of DNN, it did not achieve a significantly higher discriminative performance than the SOFT score. Future risk models will likely benefit from the inclusion of other data sources, including high-resolution clinical features for which DNNs are particularly apt to outperform conventional statistical methods.