The changing face of patients presenting for liver transplantation. Curr Opin Organ Transplant. 2008;13:280-284. [PMID: 18685318 DOI: 10.1097/mot.0b013e328300a070]

Perioperative Cardiovascular Risk Assessment and Management in Liver Transplant Recipients: A Review of the Literature Merging Guidelines and Interventions

Liver transplantation (LT) is the second most performed solid organ transplant. Coronary artery disease (CAD) is a critical consideration for LT candidacy, particularly in patients with known CAD or risk factors, including metabolic dysfunction associated with steatotic liver disease. The presence of severe CAD may exclude patients from LT; therefore, precise preoperative evaluation and interventions are necessary to achieve transplant candidacy. Cardiovascular complications represent the earliest nongraft-related cause of death post-transplantation. Timely intervention to reduce cardiovascular events depends on adequate CAD screening. Coronary disease screening in end-stage liver disease is challenging because standard noninvasive CAD screening tests have low sensitivity due to hyperdynamic state and vasodilatation. As a result, there is overuse of invasive coronary angiography to exclude severe CAD. Coronary artery calcium scoring using a computed tomography scan is a tool for the prediction of cardiovascular events, and can be used to achieve risk stratification in LT candidates. Recent literature shows that qualitative assessment on both noncontrast- and contrast-enhanced chest computed tomography can be used instead of calcium score to assess the presence of coronary calcium. With increasing prevalence, protocols to address CAD in LT candidates must be reconsidered. Percutaneous coronary intervention could allow a shorter duration of dual-antiplatelet therapy in simple lesions, with safer perioperative outcomes. Hybrid coronary revascularization is an option for high-risk LT candidates with multivessel disease nonamenable to percutaneous coronary intervention. The objective of this review is to evaluate existing methods for preoperative cardiovascular risk stratification, and to describe interventions before surgery to optimize patient outcomes and reduce cardiovascular event risk.

Predicting major adverse cardiovascular events after orthotopic liver transplantation using a supervised machine learning model: A cohort study

BACKGROUND

Liver transplant (LT) patients have become older and sicker. The rate of post-LT major adverse cardiovascular events (MACE) has increased, and this in turn raises 30-d post-LT mortality. Noninvasive cardiac stress testing loses accuracy when applied to pre-LT cirrhotic patients.

AIM

To assess the feasibility and accuracy of a machine learning model used to predict post-LT MACE in a regional cohort.

METHODS

This retrospective cohort study involved 575 LT patients from a Southern Brazilian academic center. We developed a predictive model for post-LT MACE (defined as a composite outcome of stroke, new-onset heart failure, severe arrhythmia, and myocardial infarction) using the extreme gradient boosting (XGBoost) machine learning model. We addressed missing data (below 20%) for relevant variables using the k-nearest neighbor imputation method, calculating the mean from the ten nearest neighbors for each case. The modeling dataset included 83 features, encompassing patient and laboratory data, cirrhosis complications, and pre-LT cardiac assessments. Model performance was assessed using the area under the receiver operating characteristic curve (AUROC). We also employed Shapley additive explanations (SHAP) to interpret feature impacts. The dataset was split into training (75%) and testing (25%) sets. Calibration was evaluated using the Brier score. We followed Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis guidelines for reporting. Scikit-learn and SHAP in Python 3 were used for all analyses. The supplementary material includes code for model development and a user-friendly online MACE prediction calculator.

RESULTS

Of the 537 included patients, 23 (4.46%) developed in-hospital MACE, with a mean age at transplantation of 52.9 years. The majority, 66.1%, were male. The XGBoost model achieved an impressive AUROC of 0.89 during the training stage. This model exhibited accuracy, precision, recall, and F1-score values of 0.84, 0.85, 0.80, and 0.79, respectively. Calibration, as assessed by the Brier score, indicated excellent model calibration with a score of 0.07. Furthermore, SHAP values highlighted the significance of certain variables in predicting postoperative MACE, with negative noninvasive cardiac stress testing, use of nonselective beta-blockers, direct bilirubin levels, blood type O, and dynamic alterations on myocardial perfusion scintigraphy being the most influential factors at the cohort-wide level. These results highlight the predictive capability of our XGBoost model in assessing the risk of post-LT MACE, making it a valuable tool for clinical practice.

CONCLUSION

Our study successfully assessed the feasibility and accuracy of the XGBoost machine learning model in predicting post-LT MACE, using both cardiovascular and hepatic variables. The model demonstrated impressive performance, aligning with literature findings, and exhibited excellent calibration. Notably, our cautious approach to prevent overfitting and data leakage suggests the stability of results when applied to prospective data, reinforcing the model's value as a reliable tool for predicting post-LT MACE in clinical practice.

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.

Temporary postoperative myocardial injury and long-term survival in liver transplant patients with coronary artery disease

Background: Coronary artery disease (CAD) is increasing worldwide due to the aging population and cardiometabolic syndrome. However, the extent of postoperative myocardial injury, the most common cause of death during the 30 days after noncardiac surgery, remains unclear with respect to liver transplant (LT) patients with CAD. We examined the link between post-LT high sensitivity cardiac troponin I (hs_cTnI) and long-term survival according to liver disease severity.Methods: Consecutive patients who underwent LT (n = 3,220) from 2010 to 2020 were evaluated retrospectively. CAD was defined as a history of coronary artery bypass surgery or percutaneous intervention, or previous myocardial infarction. Peak hs_cTnI levels within 30 days post-transplant were compared in patients with and without CAD. The primary endpoint was defined as an all-cause mortality at 12 years following LT. Secondary endpoints include peak hs_cTnI level within post-transplant 30 days and 30-day mortality. Survival analysis was performed using the Kaplan–Meier method.Results: CAD patients (n = 264, 8.2%) had higher peak hs_cTnI levels within 30 days post-LT than those without CAD (median [interquartile]: 0.068 [0.030–0.154] vs. 0.087 [0.037–0.203] ng/ml, respectively; P = 0.004); however, the mortality rate was comparable (14.7% vs. 14.8%, respectively, P = 0.999), at 12 years, and 1.9% vs. 1.1% (P = 0.522) at 30 days, respectively, at 30 days. Subgroup analysis with stratified liver disease severity identified a similar risk of long-term mortality.Conclusions: Although the peak hs_cTnI level within 30 days was higher in revascularized or treated CAD patients after LT compared those without CAD, long-term mortality rates at 12 years and 30-day mortality rate were comparable.

Introduction of a standardized protocol for cardiac risk assessment in candidates for liver transplant - A retrospective cohort analysis

INTRODUCTION

Recommendations on non-invasive imaging to assess pre-operative cardiac risk among liver transplant candidates vary amongst societal guidelines and individual institutional practices. In 2018, a standardized pre-transplant coronary evaluation protocol was established at Beth Israel Deaconess Medical Center, Boston MA, to ensure appropriate and consistent pre-operative testing was performed.

METHODS

All patients who underwent liver transplant evaluation between January 1st, 2016 and December 31st, 2019, were retrospectively analyzed and divided into three cohorts; before the introduction of the protocol (prior to 2018), initial protocol favoring invasive coronary angiography (ICA) (2018), and amended protocol favoring coronary computed tomography angiography (CCTA) (post-2018). We described clinical characteristics, candidacy for transplant, and cardiovascular complications during follow-up. As an unadjusted exploratory analysis, the Cochran-Armitage Exact Trend Test was used to examine univariate differences across time.

RESULTS

A total of 462 patients underwent liver transplant evaluation during the study period. Among these, 218 (47.2%) patients underwent stress test, 50 (10.8%) underwent CCTA, and 68 (14.8%) underwent ICA. Across the three time periods, there was an increase in the proportion of CCTAs performed (3%, 6.3%, and 26.3% respectively; p <0.001) and proportion of patients diagnosed with obstructive CAD using CCTA (0%, 30%, and 51.4% respectively; p = 0.04). There was no significant difference in post-transplant cardiac complications among patients evaluated before 2018, during 2018, and after 2018 (5.9% vs. 5.6 vs. 6.0%; p=1.0).

CONCLUSION

Our findings suggest it is reasonable to shift practice to a less invasive approach utilizing CCTA or nuclear stress testing when assessing liver transplant candidates at increased cardiovascular risk.

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.

Epidemiology and Prognostic Significance of Rapid Response System Activation in Patients Undergoing Liver Transplantation

Patients undergoing liver transplantation have a high risk of perioperative clinical deterioration. The Rapid Response System is an intensive care unit-based approach for the early recognition and management of hospitalized patients identified as high-risk for clinical deterioration by a medical emergency team (MET). The etiology and prognostic significance of clinical deterioration events is poorly understood in liver transplant patients. We conducted a cohort study of 381 consecutive adult liver transplant recipients from a prospectively collected transplant database (2011–2017). Medical records identified patients who received MET activation pre- and post-transplantation. MET activation was recorded in 131 (34%) patients, with 266 MET activations in total. The commonest triggers for MET activation were tachypnea and hypotension pre-transplantation, and tachycardia post-transplantation. In multivariable analysis, female sex, increasing Model for End-Stage Liver Disease score and hepatorenal syndrome were independently associated with MET activation. The unplanned intensive care unit admission rate following MET activation was 24.1%. Inpatient mortality was 4.2% and did not differ by MET activation status; however, patients requiring MET activation had significantly longer intensive care unit and hospital length of stay and were more likely to require inpatient rehabilitation. In conclusion, liver transplant patients with perioperative complications requiring MET activation represent a high-risk group with increased morbidity and length of stay.

Perioperative Skeletal Muscle Fluctuations in High-Acuity Liver Transplantation

BACKGROUND

Frailty has been implicated as a negative predictor of Liver Transplant (LT) outcomes. However, an understanding of changes in patient muscle mass peri-LT, and their effect in high-acuity patients remains lacking. We examined the impact of perioperative muscle mass changes (ΔSMI) on high-acuity (MELD ≥35) LT recipients.

MATERIALS AND METHODS

Skeletal muscle index (SMI) was calculated using CT imaging. Patients were divided into two groups, based on severity of peri-operative SMI decrease. LT recipients with chronic end-stage liver disease, MELD ≥35, and abdominal CT ≤30 days prior, and 30-90 days post LT were included. [1011 adult LT recipients reviewed, 2012-2018].

RESULTS

Of 1011 patients reviewed, 88 met inclusion criteria (median MELD 41.1). The median ΔSMI was -5.0 (-29.4 - +21.1 cm²/m²) (fig A). Patients were classified into two groups: ΔSMI<-5.0 (median ΔSMI: -0.4, n = 44) and ΔSMI>-5.0 (median ΔSMI: -9.2, n = 44). Recipients with ΔSMI<-5.0 had higher pre-LT SMI (35.4 versus 31.2 cm²/m², P <0.001) and lower post-LT SMI (26.0 versus 30.8 cm²/m², P <0.001). The ΔSMI<-5.0 group had higher early allograft dysfunction (40.9 versus 20.5%, P = 0.037), and inferior patient and graft survival (P = 0.015, 0.017, respectively). Multivariate analysis identified ΔSMI<-5.0 (HR: 2.938, P = 0.048), long cold-ischemia time (≥9h, HR: 7.332, P = 0.008), HCV (HR: 5.614, p = 0.001), and tracheostomy after LT (HR:9.218, P <0.001) as negative prognostic factors for patient survival .

CONCLUSIONS

Progressive perioperative sarcopenic deterioration was associated with inferior patient and graft survival in high acuity LT. These findings may guide pre and post-operative patient care and rehabilitation efforts in this challenging patient population.

Sarcopenia in high acuity liver transplantation: Does it predict outcomes?

BACKGROUND

Sarcopenia has gained momentum as a potential risk-stratification tool in liver transplantation (LT). While LT recipients recently have more advanced end-stage liver disease, the impact of sarcopenia in high acuity recipients with a high model for end-stage liver disease (MELD) score remains unclear.

METHODS

We retrospectively assessed sarcopenia by calculating skeletal muscle index (SMI) from cross-sectional area at third lumbar vertebra (cm² ) and height (m² ) in 296 patients with a CT ≤ 30 days prior to LT. Sex-specific SMI cut-offs were developed, and its impact was assessed in patients with MELD ≥ 35.

RESULTS

In patients with MELD ≥ 35 (n = 217), men with a SMI < 30 cm² /m² had significantly higher rates of bacteremia (P = .021) and a longer hospital stay (P < .001). Women with a SMI < 34 cm² /m² had a longer hospital stay (P = .032). There were no relationships between SMI and survival in men and women with MELD ≥ 35.

CONCLUSIONS

This series examined sarcopenia with a focus on high MELD patients. Although decreased SMI contributed to higher post-LT hospital stay, it did not impact patient survival, suggesting that while SMI alone may not aid in patient selection for LT, it certainly may guide perioperative care-planning in this challenging patient population.

Cardiovascular mortality following liver transplantation: predictors and temporal trends over 30 years

AIMS

There has been significant evolution in operative and post-transplant therapies following liver transplantation (LT). We sought to study their impact on cardiovascular (CV) mortality, particularly in the longer term.

METHODS AND RESULTS

A retrospective cohort study was conducted of all adult LTs in Australia and New Zealand across three 11-year eras from 1985 to assess prevalence, modes, and predictors of early (≤30 days) and late (>30 days) CV mortality. A total of 4265 patients were followed-up for 37 409 person-years. Overall, 1328 patients died, and CV mortality accounted for 228 (17.2%) deaths. Both early and late CV mortality fell significantly across the eras (P < 0.001). However, CV aetiologies were consistently the leading cause of early mortality and accounted for ∼40% of early deaths in the contemporary era. Cardiovascular deaths occurred significantly later than non-cardiac aetiologies (8.8 vs. 5.2 years, P < 0.001). On multivariable Cox regression, coronary artery disease [hazard ratio (HR) 4.6, 95% confidence interval (CI) 1.2-21.6; P = 0.04] and era of transplantation (HR 0.44; 95% CI 0.28-0.70; P = 0.01) were predictors of early CV mortality, while advancing age (HR 1.05, 95% CI 1.02-1.10; P = 0.005) was an independent predictors of late CV mortality. Most common modes of CV death were cardiac arrest, cerebrovascular events, and myocardial infarction.

CONCLUSION

Despite reductions in CV mortality post-LT over 30 years, they still account for a substantial proportion of early and late deaths. The late occurrence of CV deaths highlights the importance of longitudinal follow-up to study the efficacy of targeted risk-reduction strategies in this unique patient population.

Cardiac Risk Stratification in Liver Transplantation: Results of a Tiered Assessment Protocol Based on Traditional Cardiovascular Risk Factors

Coronary artery disease (CAD) confers increased perioperative risk in patients undergoing liver transplantation (LT). Although routine screening for CAD is recommended, there are limited data on the effectiveness of screening strategies. We evaluated the safety and efficacy of a 3-tiered cardiac risk-assessment protocol that stratifies patients based on age and traditional cardiac risk factors. We peformed a single-center, prospective, observational study of consecutive adult patients undergoing LT assessment (2010-2017). Patients were stratified into low-risk (LR), intermediate-risk (IR), or high-risk (HR) cardiac groups and received standardized investigations with selective use of transthoracic echocardiography (TTE), dobutamine stress echocardiography (DSE), computed tomography coronary angiography (CTCA), and coronary angiography (CA). Primary outcomes were cardiac events (CEs) and cardiovascular death up to 30 days after LT. Overall, 569 patients were included, with 76 patients identified as LR, 256 as IR, and 237 as HR. Cardiac risk factors included diabetes mellitus (26.0%), smoking history (47.3%), hypertension (17.8%), hypercholesterolemia (7.2%), family (17.0%) or prior history of heart disease (6.0%), and obesity (27.6%). Of the patients, 42.0% had ≥2 risk factors. Overall compliance with the protocol was 90.3%. Abnormal findings on TTE, DSE, and CTCA were documented in 3, 23, and 44 patients, respectively, and 12 patients were not listed for transplantation following cardiac assessment (1 LR, 2 IR, and 9 HR). Moderate or severe CAD was identified in 25.4% of HR patients on CTCA following a normal DSE. CEs were recorded in 7 patients (1.2%), with 2 cardiovascular deaths (0.4%). Cardiac risk stratification based on traditional cardiac risk factors with the selective use of DSE, CTCA, and CA is a safe and feasible approach that results in a low perioperative cardiac event rate.

The liver transplant risk score prognosticates the outcomes of liver transplant recipients at listing

BACKGROUND

We assessed if the risk of post-liver transplant mortality within 24 h could be stratified at the time of listing using the liver transplant risk score (LTRS). Secondary aims were to assess if the LTRS could stratify the risk of 30-day, 1-year mortality, and survival beyond the first year.

METHODS

MELD, BMI, age, diabetes, and the need for dialysis were the five variables used to calculate the LTRS during patients' evaluation for liver transplantation. Mortality rates at 24 h, 30 days, and 1-year were compared among groups of patients with different LTRS. Patients with ABO-incompatibility, redo, multivisceral, partial graft and malignancies except for hepatocellular carcinoma were excluded. Data of 48,616 adult liver transplant recipients were extracted from the Scientific Registry of Transplant Recipients between 2002 and 2017.

RESULTS

24-h mortality was 0.9%, 1.0%, 1.1%, 1.7%, 2.3%, 2.0% and 3.5% for patients with LTRS of 0,1,2,3,4, 5 and ≥ 6, respectively (P < 0.001). 30-day mortality was 3.5%, 4.2%, 4.9%, 6.2%, 7.6%, 7.2% and 10.1% respectively (P < 0.001). 1-year mortality was 8.6%, 10.8%, 12.9%, 13.9%, 18.5%, 20.3% and 28.6% respectively (P < 0.001). 10-year survival was 61%, 56%, 57%, 54%, 47%, and 31% for patients with 0, 1, 2, 3, 4, 5 and ≥ 6 points respectively (P < 0.001).

CONCLUSION

Perioperative mortality and long-term survival of patients undergoing LT can be accurately estimated at the time of listing by the LTRS.

In-hospital mortality of liver transplantation and risk factors: a single-center experience

Background

Liver transplantation (LT) is a life-saving treatment for patients with end-stage liver disease and acute liver failure. However, in-hospital death cannot be avoided. We designed this study to analyze patients' in-hospital mortality rate after LT and the factors correlated with in-hospital death.

Methods

The data of patients who received LT in our hospital between January 11, 2015, and November 19, 2019, were obtained from the China Liver Transplant Registry and medical records. The in-hospital mortality rate was calculated, and factors related to mortality, cause of death, and factors related to cause of death were analyzed by reviewing patients' data.

Results

A total of 529 patients who underwent cadaveric LT were enrolled in this study. Modified piggyback orthotopic LT was performed for all patients. Seventy patients died in the hospital after LT, and the in-hospital mortality rate was 13.2%. Factors including model for end-stage liver disease (MELD) score, Child-Pugh grading, intraoperative blood loss, and anhepatic phase were correlated with in-hospital death. MELD score and intraoperative blood loss were determined as the two independent risk factors of in-hospital death. The first two causes of death were infection (34.3%) and primary non-function (15.7%). Pulmonary fungal infection was the main cause of infectious death. MELD score was the independent risk factor for infectious death, and both body mass index of donors and cold ischemic time were independent risk factors of primary non-function.

Conclusions

In-hospital death poses a threat to certain patients undergoing LT. Our study suggests that the main cause of in-hospital death is an infection, followed by primary non-function.

The impact of marijuana use on liver transplant recipients: A 900 patient single center experience

INTRODUCTION

Increased societal prevalence of marijuana continues to challenge liver transplant (LT) programs. This study aimed to examine the potential effects of marijuana use on outcomes.

METHODS

This retrospective study included recipients who underwent LT between 1/2012 and 6/2018. According to pre-LT marijuana use, patients were classified into recent (≤6 months of LT), former (chronic use but not ≤6 months), or non-users. Additionally, the impact of post-LT marijuana use on survival was assessed.

RESULTS

Of 926 eligible patients, 184 were pre-LT marijuana users (42 recent; 142 former) (median follow-up: 30.3 months). Pre-users were more likely to be male, White, and have histories of tobacco, alcohol, and illicit drug use. Additionally, recent users were of higher acuity, with higher MELD and requiring ICU admission. Patient survival at 1-year was 89% in non-users, 94% (HR: 0.494, 95% CI: 0.239-1.022 vs. non-users) in former users, and 83% (HR: 1.516, 95% CI: 0.701-3.282) in recent users. Post-operative complications in pre-LT users and the survival analysis for post-LT marijuana users vs. non-users did not show significance.

CONCLUSIONS

Our results demonstrated that marijuana use did not have an adverse impact on post-LT outcomes; however, further studies utilizing larger cohorts are warranted.

Machine Learning Models to Predict Major Adverse Cardiovascular Events After Orthotopic Liver Transplantation: A Cohort Study

OBJECTIVE

To develop machine learning models that can predict post-transplantation major adverse cardiovascular events (MACE), all-cause mortality, and cardiovascular mortality in patients undergoing liver transplantation (LT).

DESIGN

Retrospective cohort study.

SETTING

High-volume tertiary care center.

PARTICIPANTS

The study comprised 1,459 consecutive patients undergoing LT between January 2008 and December 2019.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

MACE, all-cause mortality, and cardiovascular mortality were modeled using logistic regression, least absolute shrinkage and selection surgery regression, random forests, support vector machine, and gradient-boosted modeling (GBM). All models were built by splitting data into training and testing cohorts, and performance was assessed using five-fold cross-validation based on the area under the receiver operating characteristic curve and Harrell's C statistic. A total of 1,459 patients were included in the final cohort; 1,425 (97.7%) underwent index transplantation, 963 (66.0%) were female, the median age at transplantation was 57 (11-70) years, and the median Model for End-Stage Liver Disease score was 20 (6-40). Across all outcomes, the GBM model XGBoost achieved the highest performance, with an area under the receiver operating curve of 0.71 (95% confidence interval [CI] 0.63-0.79) for MACE, a Harrell's C statistic of 0.64 (95% CI 0.57-0.73) for overall survival, and 0.72 (95% CI 0.59-0.85) for cardiovascular mortality over a mean follow-up of 4.4 years. Examination of Shapley values for the GBM model revealed that on the cohort-wide level, the top influential factors for postoperative MACE were age at transplantation, diabetes, serum creatinine, cirrhosis caused by nonalcoholic steatohepatitis, right ventricular systolic pressure, and left ventricular ejection fraction.

CONCLUSION

Machine learning models developed using data from a tertiary care transplantation center achieved good discriminant function in predicting post-LT MACE, all-cause mortality, and cardiovascular mortality. These models can support clinicians in recipient selection and help screen individuals who may be at elevated risk for post-transplantation MACE.

Diagnostic accuracy of cardiac testing for coronary artery disease in potential liver transplant recipients: A systematic review and meta-analysis

Background

The incidence of coronary artery disease (CAD) in Liver transplant (LT) patients is much higher than prior estimates and the morbidity and mortality are significant in this group of patients. Coronary angiography is the gold standard for detection of CAD, a non-invasive test that allows appropriate risk stratification would be preferred. In this systematic review and meta-analysis, we sought to assess the pooled diagnostic accuracy of various noninvasive cardiac imaging tests in detecting CAD in patients listed for LT.

Methods

We performed a systematic review and meta-analysis of studies comparing sensitivity and specificity of non-invasive tests to that of coronary angiography in diagnosing coronary artery disease in patients undergoing liver transplantation.

Results

Five studies (616 participants) evaluated myocardial perfusion imaging (MPI); five studies (1243 participants) dobutamine stress echocardiography (DSE); and three (87 participants), other tests. MPI had a pooled sensitivity of 0.62 (95% CI 0.37, 0.83), specificity of 0.60 (95% CI 0.39, 0.79), diagnostic odds ratio (DOR) of 2.5 (95% CI 1.7, 5.64) and Area under the curve (AUC) 0.649. DSE had a pooled sensitivity of 0.25 (95%CI 0.09, 0.51), specificity of 0.68 (95% CI 0.44, 0.84) and DOR of 0.7 (95% CI 0.12, 3.84).

Conclusions

Our results show that both MPI and DSE are not effective screening tools for detecting CAD in patients with end-stage liver disease (ESLD). Future studies are needed to evaluate the role of real-time myocardial contrast echocardiography (RTMCE) and coronary artery calcium score (CAC) with coronary CT angiography in patients with ESLD.

Preoperative Evaluation of Coronary Artery Disease in Liver Transplant Candidates: Many Unanswered Questions in Clinical Practice

Cardiovascular (CV) complications represent the first non-graft-related cause of death and the third overall cause of death among patients undergoing liver transplantation (LT). History of coronary artery disease is related to increased CV mortality following LT. Although it is of paramount importance to stratify CV risk in pre-LT patients, there is no consensus regarding the choice of the optimal non-invasive cardiac imaging test. Algorithms proposed by scientific associations include non-traditional risk factors, which are associated with increased cardiac risk profiles. Thus, an individualized pre-LT evaluation protocol should be followed. As the average age of patients undergoing LT and the number of candidates continue to rise, the “3 W” questions still remain unanswered, Who, Which and When? Who should be screened for coronary artery disease (CAD), which screening modality should be used and when should the asymptomatic waitlisted patients repeat cardiac evaluation? Prospective studies with large sample sizes are warranted to define an algorithm that can provide better risk stratification and more reliable survival prediction.

The Impact of Previous Abdominal Surgery in a High-Acuity Liver Transplant Population

BACKGROUND

It is not uncommon for liver transplant (LT) recipients to have had previous abdominal surgery (PAS) preceding transplant. The impact of PAS on morbidity and mortality in LT patients remains unclear. In this study, we investigated the correlation between PAS and LT outcomes in a high-acuity patient population.

MATERIALS AND METHODS

This is a single-center retrospective review of 936 adult primary LT recipients between 2012 and 2018. Patients were divided based on PAS history. PAS was subdivided into upper abdominal surgery (UAS) and lower abdominal surgery (LAS). UAS was separated into high-impact UAS and low-impact UAS. Finally, we studied patients with PAS ≤90 d versus PAS >90 d.

RESULTS

Extensive adhesiolysis was the only significant perioperative factor between the PAS group (n = 367) and the non-PAS group (n = 569) (P < 0.001). Red blood cell (RBC) transfusion (20U versus 17U, P = 0.044) and abdominal packing (24.2% versus 13.3%, P = 0.008) were significantly higher in the UAS group (n = 186) versus the LAS group (n = 181). Patients with high-impact UAS required greater RBC (P = 0.021) and fresh frozen plasma transfusion (P = 0.005), and arterial conduits (P = 0.016) during LT. Compared with recipients with PAS >90 d (n = 338), recipients with PAS ≤90 d (n = 29) had significantly higher RBC transfusion (P = 0.046), fresh frozen plasma transfusion (P = 0.022), and abdominal packing (P = 0.025). No differences in patient and graft survival was observed.

CONCLUSIONS

These findings suggest that, with appropriate care in the perioperative setting, PAS is not a contraindication to successful LT. Careful consideration is warranted when risk stratifying patients with multiple comorbidities who had PAS, especially those with UAS or PAS ≤90 d.

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.

Prediction of Perioperative Mortality of Cadaveric Liver Transplant Recipients During Their Evaluations

Supplemental Digital Content is available in the text.

There are no instruments that can identify patients at an increased risk of poor outcomes after liver transplantation (LT) based only on their preoperative characteristics. The primary aim of this study was to develop such a scoring system. Secondary outcomes were to assess the discriminative performance of the predictive model for 90-day mortality, 1-year mortality, and 5-year patient survival.

SPECT myocardial perfusion imaging in liver transplantation candidates

BACKGROUND

The optimal cardiovascular evaluation prior to liver transplantation remains controversial and includes stress echocardiography, stress MPI, cardiac CTA, and coronary angiography. This study summarizes our experience of the past decade using SPECT MPI in patients with end-stage liver disease, including patient characteristics, stress testing protocols, test results, the need for repeat testing, and downstream testing.

METHODS

All patients who underwent a clinically indicated stress SPECT MPI study as part of their pre-liver transplant evaluation from 2004 to 2014 were reviewed from the Nuclear Cardiology database. Results of perfusion imaging, repeat testing, subsequent angiography, and need for revascularization were reviewed.

RESULTS

A total of 2500 patients were referred for SPECT MPI, of those 111 had known CAD and 271 underwent more than one MPI study. Compared to other patients undergoing stress MPI, pre-liver transplant patients were younger, had fewer cardiac risk factors and lower prevalence of prior cardiac history, and used pharmacologic stress more often. During the study decade, patient age increased, prevalence of hypertension increased and smoking decreased, prevalence of known CAD increased, and the number of abnormal studies decreased. Abnormal perfusion results were present in 7.8% of pre-liver transplant patients compared to 34.3% of all other patients. In a multivariate model, age and lower ejection fraction were associated with an abnormal MPI result. Of the 64 patients who underwent subsequent invasive or non-invasive coronary angiography after an abnormal MPI, obstructive CAD was diagnosed in 25 patients (1.0%), non-obstructive CAD was diagnosed in 23 patients (0.9%), and normal coronaries found in 16 patients (0.6%); a total of 18 (0.7%) of these underwent coronary revascularization. The average time to repeat testing was 27.2 ± 17.9 months. In a multivariate model, younger age and exercise stress were associated with repeat testing. In only 17 patients out of 271 with a normal initial perfusion, the repeat study became abnormal. The use of stress-first imaging was successful in 80% of patients with a reduction in Tc-99m dose from 39.1 to 18.3 mCi.

CONCLUSION

Abnormal SPECT MPI results in candidates for liver transplantation are infrequent compared to non-liver transplant patients and the incidence of obstructive CAD on subsequent angiography even less. Repeat testing in those on the transplant waiting list after initial normal test results appears to be of limited value. Stress-first protocols may be considered for the majority of these patients to reduce testing time and radiation exposure.

Postoperative Atrial Fibrillation and Flutter in Liver Transplantation: An Important Predictor of Early and Late Morbidity and Mortality

Postoperative atrial fibrillation/flutter (POAF) is the most common perioperative arrhythmia and may be particularly problematic after liver transplantation (LT). This study is a single-center retrospective analysis of POAF to determine its incidence following LT, to identify risk factors, to assess its impact on clinical outcomes, and to summarize management strategies. The records of all patients who underwent LT between 2010 and 2018 were reviewed. Extracted data included pre-LT demographics and cardiac evaluation, in-hospital post-LT cardiac events, early and late complications, and survival. Among 1011 patients, the incidence of post-LT POAF was 10%. Using binary logistic regression, pre-LT history of atrial fibrillation was the strongest predictor of POAF (odds ratio [OR], 6.72; 95% confidence interval [CI], 2.00-22.57; P < 0.001), followed by history of coronary artery disease (CAD; OR, 2.52; 95% CI, 1.10-5.81; P = 0.03). Cardiac stress testing abnormality and CAD on cardiac catheterization were also associated with higher risk. Median time to POAF onset after LT was 3 days with 72% of cases resolving within 48 hours. POAF patients had greater hospital length of stay, death during the LT admission, and 90-day and 1-year mortality. POAF was an independent risk factor for post-LT mortality (OR, 2.0; 95% CI, 1.3-3.0; P < 0.01). Amiodarone was administered to 73% of POAF patients with no evidence of increased serum alanine aminotransferase levels. POAF occurred in 10% of post-LT patients with early onset and rapid resolution in most affected patients. POAF patients, however, had significant morbidity and mortality, suggesting that POAF is an important marker for worse early and late post-LT outcomes.

Effects of Share 35 Policy on Liver Transplantation Outcomes for Patients With Nonalcoholic Steatohepatitis

BACKGROUND

To examine the temporal variation and outcomes of liver transplantation between pre- and post-Share 35 eras for patients with nonalcoholic steatohepatitis.

METHODS

A retrospective analysis was performed among 4380 patients with end-stage liver disease from the United Network for Organ Sharing database from 2009 to 2017 due to primary diagnosis of nonalcoholic steatohepatitis or cryptogenic cirrhosis with body mass index greater than 30. Cox regressions were used to model the effect of Share 35 policy on patient and graft survival comparing the first 3 years of Share 35 policy to an equivalent time period before.

RESULTS

The number of nonalcoholic steatohepatitis-related transplants increased from 232 (14.1%) in 2009 to 266 (20.5%) in 2017. In post-Share 35 era, average waitlist time and cold ischemic time decreased, while Model for End-Stage Liver Disease (MELD) scores increased with higher proportion of recipients having MELD ≥35. No significant difference in average length of hospitalization or survival was found after Share 35.

CONCLUSIONS

The Share 35 policy benefits patients with nonalcoholic steatohepatitis from reduced liver transplantation waiting time. It is also associated with comparable outcomes in 2 eras without increasing cold ischemic time or posttransplant length of hospitalization.

Cardiac stress testing and coronary artery disease in liver transplantation candidates: Meta-analysis

AIM

To evaluate the diagnostic value of dobutamine stress echocardiography (DSE) and myocardial perfusion scintigraphy (MPS) in predicting coronary artery disease (CAD) in cirrhotic patients listed for liver transplantation (LT), using invasive coronary angiography (ICA) as gold-standard.

METHODS

Retrieval of studies was based on Medical Subject Headings and Health Sciences Descriptors, which were combined using Boolean operators. Searches were run on the electronic databases Scopus, Web of Science, EMBASE, MEDLINE (PubMed), BIREME (Biblioteca Regional de Medicina), LILACS (Latin American and Caribbean Health Sciences Literature), Cochrane Library for Systematic Reviews and Opengray.eu. There was no language or date of publication restrictions. The reference lists of the studies retrieved were searched manually.

RESULTS

The search strategy retrieved 322 references for DSE and 90 for MPS. In the final analysis, 10 references for DSE and 10 for MPS were included. Pooled sensitivity was 28% and 61% for DSE and MPS and specificity was 82% and 74%, for diagnosis of CAD using ICA as gold-standard, respectively.

CONCLUSION

DSE and MPS do not have adequate sensitivity for determination of whether CAD is present, despite having significant specificity.

[Frontiers in liver transplantation in indication and techniques]

BACKGROUND

The frontiers in liver transplantation are intrinsically expansions of indications, e.g. hepatocellular carcinoma and (perihilar) cholangiocarcinoma, recipients with more severe concomitant diagnoses or "soft" contraindications and technically demanding reconstruction procedures of vascular structures (for portal vein thrombosis or aorto-hepatic conduits). In addition, an extension of the donor pool with suboptimal donor organs (old donors and steatotic livers) is of interest.

METHODS

This article presents the current situation based on personal experiences in daily practice and an appropriate literature review.

RESULTS

A significant reduction of 1‑year patient survival has been reported in Germany. The percentage of so-called marginal donor organs is inversely proportional to the very low donation rate and parallel to the waiting list mortality. Simultaneously, the proportion of inpatients with multiple organ failure is rising.

CONCLUSION

Results-oriented and controlled liver transplantation currently prohibits making inroads into the previously intrinsic frontiers. As long as the current circumstances do not change, a shift in the intrinsic frontiers of that which is surgically feasible will not be possible. The current situation forces the transplant surgeon to apply a more restrictive indications and organ acceptance policy. With this approach we can try to regain the previously excellent short- and long-term results of a 1‑year survival of 90% and a 20-year survival of 50%.

Serum Caspase-Cleaved Cytokeratin (M30) Indicates Severity of Liver Dysfunction and Predicts Liver Outcome

BACKGROUND The Model for End-Stage Liver Disease (MELD) score is a well-established tool for assessing hepatic failure. The present retrospective study investigated whether serum keratin 18 (M65) and caspase-cleaved cytokeratin (M30) were associated with liver dysfunction and post-transplant graft failure. MATERIAL AND METHODS A total of 147 patients with liver cirrhosis were categorized into 2 groups according to their baseline MELD score (group I: MELD score <20, n=87, and group II: MELD score ≥20, n=60). Serum M65 and M30 levels were measured by ELISA. RESULTS Cirrhotic patients had significantly higher serum M65 and M30 levels than healthy controls (p<0.0001). Serum M65 was correlated with the MELD score and serum bilirubin (p≤0.007) and serum M30 was correlated with the MELD score, international normalized ratio, and serum bilirubin (p≤0.001). Group II had significantly higher serum M65 and M30 levels than group I (M65, p=0.025 and M30, p<0.001). Patients who lost the allograft during the first post-transplant year had significantly higher serum M30 levels than patients with a graft survival of >1 year (p=0.004). In the regression analysis, serum M30 was associated with the MELD score (odds ratio [OR]=2.545, p=0.005), serum bilirubin (OR=2.605, p=0.005) and 1-year graft loss (OR=3.61, p=0.006). CONCLUSIONS Our data indicate that serum M30 levels reflect the degree of liver dysfunction and can predict 1-year graft loss.

Cardio-hepatic risk assessment by CMR imaging in liver transplant candidates

BACKGROUND

The preoperative workup of orthotopic liver transplantation (OLT) patients is practically complex given the need for multiple imaging modalities. We recently demonstrated in our proof-of-concept study the value of a one-stop-shop approach using cardiovascular MRI (CMR) to address this complex problem. However, this approach requires further validation in a larger cohort, as detection of hepatocellular carcinoma (HCC) as well as cardiovascular risk assessment is critically important in these patients. We hypothesized that coronary risk assessment and HCC detectability is acceptable using the one-stop-shop CMR approach.

METHODS

In this observational study, patients underwent CMRI evaluation including cardiac function, stress CMR, thoracoabdominal MRA, and abdominal MRI on a standard MRI scanner in one examination.

RESULTS

Over 8 years, 252 OLT candidates underwent evaluation in the cardiac MRI suit. The completion rates for each segment of the CMR examination were 99% for function, 95% completed stress CMR, 93% completed LGE for viability, 85% for liver MRI, and 87% for MRA. A negative CMR stress examination had 100% CAD event-free survival at 12 months. A total of 63 (29%) patients proceeded to OLT. Explant pathology confirmed detection/exclusion of HCC.

CONCLUSIONS

This study further defines the population suitable for the one-stop-shop CMR concept for preop evaluation of OLT candidates providing a road map for integrated testing in this complex patient population for evaluation of cardiac risk and detection of HCC lesions.

Dobutamine stress echocardiography, myocardial perfusion scintigraphy, invasive coronary angiography, and post-liver transplantation events: Systematic review and meta-analysis

The impact of coronary artery disease on the clinical course of patients enrolled for liver transplantation (LT) has changed over the years as these patients become older and sicker. The purpose of this systematic review and meta-analysis was to investigate the value of dobutamine stress echocardiography (DSE), myocardial perfusion scintigraphy (MPS), and invasive coronary angiography (ICA) in predicting cardiac events post-LT in cirrhotic patients. A literature search was conducted using Scopus, Web of Science, EMBASE, MEDLINE (via PubMed), BIREME (regional medical library of the Pan American Health Organization), LILACS (Latin American and Caribbean Health Sciences Literature), Cochrane Library for Systematic Reviews, and OpenGrey Repository (www.opengrey.eu) electronic databases. A total of 322 records were retrieved for DSE, 90 for MPS, and 149 for ICA. In the final analysis, 11 records for DSE, 7 for MPS, and 8 for ICA were included. The relative risk and confidence interval for major adverse cardiac events were 30.2 (2.8-325.4) for DSE, 2.6 (1.09-6.1) for MPS, and 2.1 (1.0-2.3) for ICA, while the relative risk and confidence interval for all-cause mortality was 4.7 for DSE (1.8-12.0), 2.7 (1.25-5.9) for MPS, and 1.5 (0.89-3.2) for ICA. In conclusion, this meta-analysis found that DSE, MPS, and ICA do not satisfactorily predict increased risk of perioperative MACE or all-cause mortality among cirrhotic patients listed for LT, among small and heterogenous studies.

Multidisciplinary approach to cardiac and pulmonary vascular disease risk assessment in liver transplantation: An evaluation of the evidence and consensus recommendations

Liver transplant (LT) candidates today are older, have greater medical severity of illness, and have more cardiovascular comorbidities than ever before. In addition, there are specific cardiovascular responses in cirrhosis that can be detrimental to the LT candidate. Cirrhotic cardiomyopathy, a condition characterized by increased cardiac output and a reduced ventricular response to stress, is present in up to 30% of patients with cirrhosis, thus challenging perioperative management. Current noninvasive tests that assess for subclinical coronary and myocardial disease have low sensitivity, and altered hemodynamics during the LT surgery can unmask latent cardiovascular disease either intraoperatively or in the immediate postoperative period. Therefore, this review, assembled by a group of multidisciplinary experts in the field and endorsed by the American Society of Transplantation Liver and Intestine and Thoracic and Critical Care Communities of Practice, provides a critical assessment of the diagnosis of cardiac and pulmonary vascular disease and interventions aimed at managing these conditions in LT candidates. Key points and practice-based recommendations for the diagnosis and management of cardiac and pulmonary vascular disease in this population are provided to offer guidance for clinicians and identify gaps in knowledge for future investigations.

Perioperative Care of the Liver Transplant Patient

With the evolution of surgical and anesthetic techniques, liver transplantation has become "routine," allowing for modifications of practice to decrease perioperative complications and costs. There is debate over the necessity for intensive care unit admission for patients with satisfactory preoperative status and a smooth intraoperative course. Postoperative care is made easier when the liver graft performs optimally. Assessment of graft function, vigilance for complications after the major surgical insult, and optimization of multiple systems affected by liver disease are essential aspects of postoperative care. The intensivist plays a vital role in an integrated multidisciplinary transplant team.

Impact of acute-on-chronic liver failure on 90-day mortality following a first liver transplantation

BACKGROUND

Acute-on-chronic liver failure (ACLF) is associated with a significant short-term mortality rate (23%-74%), depending on the number of organ failures. Some patients present with ACLF at the time of liver transplantation (LT). The aim of this study was to assess whether ACLF was also a prognostic factor after LT and, if applicable, to construct a score that could predict 90-day mortality.

METHODS

Three hundred and fifty cirrhotic patients, who underwent LT between January 2008 and December 2013, were enrolled. We used ACLF grades according to EASL-CLIF consortium criteria to categorize the cirrhotic patients. A propensity score was applied with an Inverse Probability Treatment Weighting in a Cox model. A predictive score of early mortality after LT was generated.

RESULTS

One hundred and forty patients (40%) met the criteria for ACLF. The overall mortality rate at 90 days post-transplant was 10.6% (37/350 patients). ACLF at the time of LT (HR: 5.78 [3.42-9.77], P<.001) was an independent predictor of 90-day mortality. Infection occurring during the month before LT, high recipient age and male recipient, the reason for LT and a female donor were also independent risk factors for early mortality. Using these factors, we have proposed a model to predict 90-day mortality after LT.

CONCLUSIONS

LT is feasible in cirrhotic patients with ACLF. However, we have shown that ACLF is a significant and independent predictor of 90-day mortality. We propose a score that can identify candidate cirrhotic patients in whom LT might be associated with futile LT.

High MELD score and extended operating time predict prolonged initial ICU stay after liver transplantation and influence the outcome

BACKGROUND

The aim of the present study is to determine the incidence of a prolonged (>3 days) initial ICU-stay after liver transplantation (LT) and to identify risk factors for it.

PATIENTS AND METHODS

We retrospectively analyzed data of adult recipients who underwent deceased donor first-LT at the University Hospital Essen between 11/2003 and 07/2012 and showed a primary graft function.

RESULTS

Of the 374 recipients, 225 (60.16%) had prolonged ICU-stay. On univariate analysis, donor INR, high doses of vasopressors, "rescue-offer" grafts, being hospitalized at transplant, high urgency cases, labMELD, alcoholic cirrhosis, being on renal dialysis and length of surgery were associated with prolonged ICU-stay. After multivariate analysis, only the labMELD and the operation's length were independently correlated with prolonged ICU-stay. Cut-off values for these variables were 19 and 293.5 min, respectively. Hospital stay was longer for patients with a prolonged initial ICU-stay (p<0.001). Survival rates differed significantly between the two groups at 3 months, 1-year and 5-years after LT (p<0.001).

CONCLUSIONS

LabMELD and duration of LT were identified as independent predictors for prolonged ICU-stay after LT. Identification of recipients in need of longer ICU-stay could contribute to a more evidenced-based and cost-effective use of ICU facilities in transplant centers.

Preoperative Cardiac Risk Assessment in Patients Undergoing Liver Transplant Due to Hepatocellular Carcinoma: Should It Be Different?

OBJECTIVES

Liver transplant is a high-risk surgery for cardiac events. The risk of 30-day major cardiac adverse events is estimated at more than 5%. In this retrospective study, we evaluated our preoperative cardiac risk assessment approach.

MATERIALS AND METHODS

We evaluated 58 adult patients who underwent liver transplant between May 2011 and May 2015. Preoperative cardiac risk factors and results of diagnostic tests were noted. Patients were divided into 2 groups: patients with or without hepatocellular carcinoma. Electrocardiogram, echocardiogram, and treadmill tests were performed for preoperative cardiac evaluation in all candidates for liver transplant. Results of these tests showed our preference for myocardial perfusion scintigraphy and/or coronary angiography and heart catheterization.

RESULTS

Mean age of patients was 46.5 ± 14.5 years. The most common cardiovascular risk factor was family history of coronary artery disease (24.1%) in all patients. Diabetes mellitus (15.5%) was the most common risk factor in the patient group without hepatocellular carcinoma. Three patients had already known coronary artery disease (5.2%). Of 16 patients (27.6%) who underwent coronary angiography, 4 were in the hepatocellular carcinoma group. Coronary revascularization by stent implantation was necessary for 1 patient in the hepatocellular carcinoma group; 1 patient in the group without hepatocellular carcinoma underwent preoperative coronary bypass surgery.

CONCLUSIONS

No consensus exists for cardiovascular risk stratification and preoperative cardiovascular evaluation of liver transplant candidates. Noninvasive stress tests are not always feasible for all liver transplant candidates because of poor mobility and poor exercise capacity. With early diagnoses of cardiovascular conditions and preventive recommendations, liver transplant can be performed safely before spread of the disease, which is essential for carcinoma patients. Angiographic evaluation of liver transplant candidates for hepatocellular carcinoma is strongly recommended.

Female Gender of the Recipient Is Independently Associated With Prolonged Ventilation Time and Hospital Stay After Liver Transplantation

BACKGROUND

Although female patients are associated with several complications after liver transplantation (OLT), its role in short-term postoperative outcomes is not known. The aims of this study were to investigate the relationship between female gender and ventilation time and hospital stay after OLT.

METHODS

After receiving institutional review board approval, we studied adult patients who underwent OLT at our center between 2004 and 2013. Female and male recipients were compared by using Student t and χ(2) tests. Risk factors were confirmed in multivariate logistic models.

RESULTS

Of 1476 patients, 490 were female. Compared with male counterparts, female recipients had more severe disease and comorbidities. Intraoperatively, the 2 groups were similar except for blood transfusion. Postoperatively, female recipients required significantly longer ventilation time (median, 3 days [interquartile range (IQR), 2-5], vs median, 2 [IQR, 1-5]; P = .009) and duration of hospital stay (median, 23 [IQR, 15-46] vs median, 18 [IQR, 12-34]; P < .001) compared with male recipients. Female gender was an independent risk factor for prolonged posttransplant ventilation time (≥3 days; odds ratio [OR], 1.65; P < .001) and hospital stay (≥19 days; OR, 1.48; P = .003).

CONCLUSIONS

Female gender of the recipient is associated with significantly longer ventilation time and hospital stay after OLT and the management should be tailored to the unique characteristics and susceptibility to postoperative complications in female patients.

Effectively Screening for Coronary Artery Disease in Patients Undergoing Orthotopic Liver Transplant Evaluation

Coronary artery disease (CAD) is prevalent in patients with end-stage liver disease and associated with poor outcomes when undergoing orthotopic liver transplantation (OLT); however, noninvasive screening for CAD in this population is less sensitive. In an attempt to identify redundancy, we reviewed our experience among patients undergoing CAD screening as part of their OLT evaluation between May 2009 and February 2014. Demographic, clinical, and procedural characteristics were analyzed. Of the total number of screened patients (n = 132), initial screening was more common via stress testing (n = 100; 75.8%) than coronary angiography (n = 32; 24.2%). Most with initial stress testing underwent angiography (n = 52; 39.4%). Among those undergoing angiography, CAD was common (n = 31; 23.5%). Across the entire cohort the number of traditional risk factors was linearly associated with CAD, and those with two or more risk factors were found to have CAD by angiography 50% of the time (OR 1.92; CI 1.07–3.44, p = 0.026). Our data supports that CAD is prevalent among pre-OLT patients, especially among those with 2 or more risk factors. Moreover, we identified a lack of uniformity in practice and the need for evidence-based and standardized screening protocols.

Acute kidney injury following liver transplantation: a systematic review of published predictive models

Acute kidney injury is a frequent postoperative complication amongst liver transplant recipients and is associated with increased morbidity and mortality. This systematic review analysed the existing predictive models, in order to solidify current understanding. Articles were selected for inclusion if they described the primary development of a clinical prediction model (either an algorithm or risk score) to predict AKI post liver transplantation. The database search yielded a total of seven studies describing the primary development of a prediction model or risk score for the development of AKI following liver transplantation. The models span thirteen years of clinical research and highlight a gradual change in the definitions of AKI, emphasising the need to employ standardised definitions for subsequent studies. Collectively, the models identify a diverse range of predictive factors with several common trends. They emphasise the impact of preoperative renal dysfunction, liver disease severity and aetiology, metabolic risk factors as well as intraoperative variables including measures of haemodynamic instability and graft quality. Although several of the models address postoperative parameters, their utility in predictive modelling seems to be of questionable relevance. The common risk factors identified within this systematic review provide a minimum list of variables, which future studies should address. Research in this area would benefit from prospective, multi-site studies with larger cohorts as well as the subsequent internal and external validation of predictive models. Ultimately, the ability to identify patients at high risk of post-transplant AKI may enable early intervention and perhaps prevention.

The evaluation of hemodynamic changes during the reperfusion phase in adult living donor liver transplantations: the role of cardiovascular problems

OBJECTIVE

This study sought to evaluate the hemodynamic changes of and to analyze the effects of coronary artery disease (CAD) as well as its risk factors on hemodynamic parameters during the reperfusion phase (RP) in adult living donor liver transplantation (ALDLT).

PATIENTS AND METHODS

This single-center retrospective study evaluated 154 adult patients being assessed from January 2001 to December 2013 for orthotopic liver transplantation (OLT). The patients were divided into separate groups according to the presence or absence of CAD and its risk factors, including diabetes, hypertension, dyslipidemia, smoking, sex, and age. The hemodynamic parameters were noted during the RP with respect to the patient files. The comparison of the groups and the effects of cardiovascular problems on hemodynamic parameters were statistically analyzed.

RESULTS

A decrease of more than 20% in systolic arterial pressure was seen in 16 (16.7%), 7 (43.8%), and 17 (40.5%) patients without CAD, with CAD, and with its high risk factors (>2), respectively (P < .05). Moreover, diastolic hypotension was seen in 59 (38.3%) patients during RP; of those, 10 (62.5%) had CAD and 19 (45.2%) had CAD high-risk factors. The decline in both systolic and diastolic arterial pressure was significantly correlated with the increased number of risk factors (P < .05).

CONCLUSIONS

RP in ALDLT remains an issue not only for the surgeons but also for the anesthesiologists. Clinicians should be aware of CAD and its risk factors before OLT and successful management of such problems are mandatory for hemodynamic stability during this formidable process.

Preoperative cardiovascular investigations in liver transplant candidate: An update

Cardiovascular complications are a major cause of morbidity and mortality in patients with end-stage liver disease (ESLD) undergoing liver transplantation. Identifying candidates at the highest risk of postoperative cardiovascular complications is the cornerstone for optimizing the outcome. Ischaemic heart disease contributes to major portion of cardiovascular complications and therefore warrants evaluation in the preoperative period. Patients of ESLD usually demonstrate increased cardiac output, compromised ventricular response to stress, low systemic vascular resistance and occasionally bradycardia. Despite various recommendations for preoperative evaluation of cardiovascular disease in liver transplant candidates, a considerable controversy on screening methodology persists. This review critically focuses on the rapidly expanding body of evidence for diagnosis and risk stratification of cardiovascular disorder in liver transplant candidates.

Perioperative predictors for refractory hyperglycemia during the neohepatic phase of liver transplantation

BACKGROUND

Hyperglycemia in the neohepatic phase of liver transplantation (LT) tends to decrease toward completion of the surgical procedure. Refractory hyperglycemia in the neohepatic phase (RH) is influenced by multiple perioperative factors and may be connected to posttransplant outcomes. We attempted to demonstrate the relationship of RH to posttransplant outcomes and to establish a predictive model for RH in living donor liver transplantation (LDLT).

METHODS

Perioperative data of 211 patients who underwent LDLT from 2009 and 2012 were reviewed, including declines in the blood glucose levels during the neohepatic phase. Perioperative variables including the posttransplant model for end-stage liver disease (MELD) score until day 30 were compared between patients with normal declines in blood glucose and patients with RH. Selected variables after intergroup comparisons were examined by means of multivariate logistic regression to establish a predictive model for RH occurrence.

RESULTS

The mean blood glucose decline was 22.3 ± 31.5 mg/dL during the neohepatic phase, and 84 of 203 patients (41.4%) had no decline in blood glucose. In intergroup comparisons, preoperative factors associated with RH included sex, Child-Pugh-Turcotte class, MELD score, emergency, liver enzymes, and graft-to-recipient weight ratio. During surgery, surgical time, serum lactate, and arterial pH were associated with RH. After surgery, the RH group showed slower recovery of the MELD score (15.2 versus 11.9 days) and higher MELD scores until day 10 (P < .05). After the multivariate analysis, recipient sex, emergency, surgical time (≤9 h), and the final intraoperative serum lactate level (≥5.0 mmol/L) were included in the predictive model for RH.

CONCLUSIONS

RH was associated with delayed functional recovery of the liver graft in LT. Recipient sex, emergency, surgical time, and the final intraoperative serum lactate level were identified as predictors of RH. Close monitoring of intraoperative blood glucose in LDLT may be an early prognostic indicator.

Early post-transplant survival: Interaction of MELD score and hospitalization status

BACKGROUND & AIMS

Urgency-based allocation that relies on the MELD score prioritizes patients at the highest risk of waitlist mortality. However, identifying patients at greatest risk for short-term post-transplant mortality is needed in order to optimize the potential gains in overall survival obtained through improved long-term management of transplant recipients. There are limited data on the predictive ability of MELD score for early post-transplant mortality, and no data assessing the interaction between MELD score and hospitalization status.

METHODS

We analyzed UNOS data from 2002 to 2013 on 50,838 non-status 1 single-organ liver transplant recipients and fit multivariable logistic models to evaluate the association and interaction between MELD score and pre-transplant hospitalization status on short-term post-transplant mortality.

RESULTS

There was a significant interaction (p<0.01) between laboratory MELD score and hospitalization status on three-, six-, and 12-month post-transplant mortality in multivariable logistic models. This interaction was most pronounced in patients with a laboratory MELD score <25 transplanted from an ICU, whose adjusted predicted three-, six-, and 12-month post-transplant mortality approximated those of patients with a MELD score ⩾30. Compared to hospitalized patients with a MELD score of 30-34, those with a MELD score ⩾35 in an ICU had significantly increased risk of three-month (OR: 1.54, 95% CI: 1.21-1.97), 6-month (OR: 1.35, 95% CI: 1.09-1.67), and 12-month (OR: 1.25, 95% CI: 1.03-1.52) post-transplant mortality.

DISCUSSION

Pre-transplant ICU status modifies the risk of early post-transplant mortality, independent of MELD score. This should be considered when determining candidacy for transplantation in order to optimize efficient use of a scarce resource.

Cardiac imaging for the assessment of patients being evaluated for kidney or liver transplantation

Cardiac risk assessment prior to kidney and liver transplantation is controversial. Given the paucity of available organs, selecting appropriate recipients with favorable short- and long-term cardiovascular risk profile is crucial. Using noninvasive cardiac imaging tools to guide cardiovascular risk assessment and management can also be challenging and controversial. In this article, we address the burden of coronary artery disease among kidney and liver transplant candidates and review the literature pertaining to the diagnostic accuracy and the prognostic value of noninvasive cardiac imaging techniques in this population.

Postoperative atrial fibrillation in liver transplantation

Postoperative atrial fibrillation (POAF) is common after major surgeries and is associated with increased morbidity and mortality. POAF after liver transplantation (LT) has not been reported. This study was undertaken to investigate the incidence, impact, and risk factors of POAF in LT patients. After IRB approval, LT between January 2006 and August 2013 at our center were retrospectively reviewed. POAF that occurred within 30 days after LT was included. Patients with and without POAF were compared and independent risk factors were identified by logistic regression. Of 1387 adults LT patients, 102 (7.4%) developed POAF during the study period. POAF was associated with significantly increased mortality, graft failure, acute kidney injury and prolonged hospital stay. Independent risk factors included age, body weight, MELD score, presence of previous history of AF, the vasopressors use prior to LT and pulmonary artery diastolic pressure at the end of LT surgery (odds ratios 2.0-7.2, all p < 0.05). A risk index of POAF was developed and patients with the high-risk index had more than 60% chance of developing POAF. These findings may be used to stratify patients and to guide prophylaxis for POAF in the posttransplant period.

Coronary Computed Tomographic Angiography in the Evaluation of Liver Transplant Candidates

The feasibility, safety, and value of coronary computed tomographic angiography (CCTA) in evaluating orthotopic liver transplant (OLT) candidates are unknown. We studied a cohort of consecutive OLT candidates with intermediate-to-high risk of coronary artery disease (CAD). Intermediate risk candidates received CCTA, and those at high risk or with abnormal noninvasive testing underwent invasive coronary angiography (ICA). One hundred consecutive patients were evaluated. Fifty patients underwent a CCTA, 71.4% were β-blocked, the image quality was "good" or "excellent" in 71.4% of cases, and there was no event of significant contrast-induced nephropathy. Twenty (20%) patients were found to have severe CAD (≥70% stenosis) by CCTA and/or ICA. Independent predictors of severe CAD were age (odds ratio [OR] = 5.4 per 10-year increment, 95% confidence interval [CI] = 1.7-17.0; P = .004), dyslipidemia (OR = 12.3, 95% CI = 2.6-57.6; P = .001), and chest pain (OR = 6.0, 95% CI = 1.2-29.1; P = .03). Implementing CCTA in the evaluation of intermediate/high CAD risk OLT candidates is challenging but feasible and seems safe.