Preoperative cardiac assessment in liver transplant candidates

Perioperative Variation of Plasma Copeptin and Its Association With Vasopressor Need During Liver Transplantation

BACKGROUND

Vasopressor usage during liver transplant is related to decreased hepatic flow, graft failure, and mortality. We measured plasma Copeptin levels in liver transplant patients based on vasopressor requirements. We hypothesize that preoperative plasma copeptin measurement helps predict the vasopressor infusion requirement during liver transplantation in preoperative evaluation.

METHODS

The plasma Copeptin of 40 patients was measured 5 times: before the operation, 15 minutes before and after reperfusion, and postoperative 12th and 24th hours. Patients were categorized into 2 groups based on vasopressor infusion for comparison.

RESULTS

There was a statistically significant rise in median serum Copeptin concentration between the preoperative phase and before reperfusion (11.2 [7.3-20.9] vs 178.5 [121.5-243.0], P < .001), as well as a statistically substantial decline between after reperfusion and postoperative 12th hours (190.6 [127-276.3] vs 74.7 [42.0-124.9], P < .001). The vasopressor-taking group had significantly higher plasma copeptin at postoperative 12th hours (96.6 [71.4-191.7] vs 55.0 [31.8-82.5], P = .030) and 24th (133.7 [72.2-175.5] vs 51.1 [24.8-85.8], P = .037). A tendency above 11.85 pmol/L of plasma Copeptine level was observed between increasing preoperative plasma Copeptin and the odds of vasopressor use.

CONCLUSION

High preoperative plasma Copeptin levels may be an indicator of vasopressor need during liver transplantation. Further studies with more samples, including a higher range of preoperative plasma Copeptin levels, are required to provide more generalizable findings and to determine thresholds applicable to LT candidates.

Liver Transplantation and the Older Adults Candidate: Perioperative Considerations

Pioneered by Thomas Starzl in the early 1970s, liver transplant (LT) is nowadays often considered a final intervention and standard of care to cure many forms of acute and chronic end-stage liver diseases. Started in recipients younger than 60 years old, LT indications are now much broader, and at least, one-fifth of the candidates are older than 65 years. Problems associated with ageing and frailty in LT recipients and their impact on the entire perioperative course are discussed according to a modern anesthesiological perspective and the anesthesiologist covering the role of the perioperative (transplant) physician.

Major liver resections, perioperative issues and posthepatectomy liver failure: A comprehensive update for the anesthesiologist

Significant advances in surgical techniques and relevant medium- and long-term outcomes over the past two decades have led to a substantial expansion in the indications for major liver resections. To support these outstanding results and to reduce perioperative complications, anesthesiologists must address and master key perioperative issues (preoperative assessment, proactive intraoperative anesthesia strategies, and implementation of the Enhanced Recovery After Surgery approach). Intensive care unit monitoring immediately following liver surgery remains a subject of active and often unresolved debate. Among postoperative complications, posthepatectomy liver failure (PHLF) occurs in different grades of severity (A-C) and frequency (9%-30%), and it is the main cause of 90-d postoperative mortality. PHLF, recently redefined with pragmatic clinical criteria and perioperative scores, can be predicted, prevented, or anticipated. This review highlights: (1) The systemic consequences of surgical manipulations anesthesiologists must respond to or prevent, to positively impact PHLF (a proactive approach); and (2) the maximal intensive treatment of PHLF, including artificial options, mainly based, so far, on Acute Liver Failure treatment(s), to buy time waiting for the recovery of the native liver or, when appropriate and in very selected cases, toward liver transplant. Such a clinical context requires a strong commitment to surgeons, anesthesiologists, and intensivists to work together, for a fruitful collaboration in a mandatory clinical continuum.

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.

Myocardial perfusion scintigraphy in the assessment of cardiovascular risk in adult liver transplantation

INTRODUCTION

The non-invasive diagnostic study of cardiovascular risk in patients who are going to undergo liver transplantation is not clear, especially in asymptomatic patients. Regarding myocardial perfusion scintigraphy (MPS), it has been thought that the impaired vasodilator reserve in these patients may reduce its performance. The objective is to assess the role of the MPS in the pre-surgical evaluation of patients who are going to undergo liver transplantation.

MATERIAL AND METHODS

Retrospective, descriptive and observational study was designed. All adult patients undergoing liver transplantation between 2017 and 2021 who had previous MPS were included. The findings of MPS were described and correlated with the findings of invasive angiography and with the appearance or not of peri- and post-transplant cardiovascular events.

RESULTS

There were a total of 188 transplanted patients (mean age: 57 years, SD: 12), 178 had previous myocardial perfusion, 82 (46%) patients had no cardiovascular risk factors, and 5 (2.8%) had a history of coronary disease. Of the MPS, 177 were with dipyridamole stress performed on average 10 months before transplantation. Only 17/178 (9.5%) studies were abnormal. The mean follow-up was 38 months (SD: 10). Of the patients with normal MPS, only 2 (1.2%) presented cardiovascular events, both with studies performed more than 2 years before the procedure. There were no deaths of cardiovascular origin.

CONCLUSIONS

MPS is a safe and reliable technique for cardiovascular assessment of patients who are candidates for liver transplantation, given the low rate of false negatives during follow-up.

Liver Transplantation and the Elderly Candidate: Perioperative Considerations

Pioneered by Thomas Starzl in the early 1970s, liver transplant (LT) is nowadays often considered a final intervention and standard of care to cure many forms of acute and chronic end-stage liver diseases. Started in recipients younger than 60 years old, LT indications are now much broader, and at least, one-fifth of the candidates are older than 65 years. Problems associated with ageing and frailty in LT recipients and their impact on the entire perioperative course are discussed according to a modern anesthesiological perspective and the anesthesiologist covering the role of the perioperative (transplant) physician.

Liver transplantation for NAFLD cirrhosis: Age and recent coronary angioplasty are major determinants of survival

BACKGROUND AND AIMS

Liver transplantation (LT) is the treatment of end-stage non-alcoholic liver disease (NAFLD), that is decompensated cirrhosis and/or complicated by hepatocellular carcinoma (HCC). Few data on long-term outcome are available. The aim of this study was to evaluate overall patient and graft survivals and associated predictive factors.

METHOD

This retrospective multicentre study included adult transplant patients for NAFLD cirrhosis between 2000 and 2019 in participating French-speaking centres.

RESULTS

A total of 361 patients (69.8% of male) were included in 20 centres. The median age at LT was 62.3 years [57.4-65.9] and the median MELD score was 13.9 [9.1-21.3]; 51.8% of patients had HCC on liver explant. Between 2004 and 2018, the number of LT for NAFLD cirrhosis increased by 720%. A quarter of the patients had cardiovascular history before LT. Median follow-up after LT was 39.1 months [15.8-72.3]. Patient survival at 1, 5 and 10 years after LT was 89.3%, 79.8% and 68.1% respectively. The main causes of death were sepsis (37.5%), malignancies (29.2%) and cardiovascular events (22.2%). In multivariate analysis, three risk factors for overall mortality after LT were recipient pre-LT BMI < 32 kg/m² at LT time (OR: 2.272; p = .012), pre-LT angioplasty during CV check-up (OR: 2.916; p = .016), a combined donor and recipient age over 135 years (OR: 2.020; 95%CI: p = .035).

CONCLUSION

Survival after LT for NAFLD cirrhosis is good at 5 years. Donor and recipient age, and cardiovascular history, are major prognostic factors to consider.

Cardiac risk stratification of the liver transplant candidate: A comprehensive review

Cardiovascular diseases (CVD) form a principal consideration in patients with end-stage liver disease (ESLD) undergoing evaluation for liver transplant (LT) with prognostic implications in the peri- and post-transplant periods. As the predominant etiology of ESLD continues to evolve, addressing CVD in these patients has become increasingly relevant. Likewise, as the number of LTs increase by the year, the proportion of older adults on the waiting list with competing comorbidities increase, and the demographics of LT candidates evolve with parallel increases in their CVD risk profiles. The primary goal of cardiac risk assessment is to preemptively reduce the risk of cardiovascular morbidity and mortality that may arise from hemodynamic stress in the peri- and post-transplant periods. The complex hemodynamics shared by ESLD patients in the pre-transplant period with adverse cardiovascular events occurring in only some of these recipients continue to challenge currently available guidelines and their uniform applicability. This review focusses on cardiac assessment of LT candidates in a stepwise manner with special emphasis on preoperative patient optimization. We hope that this will reinforce the importance of cardiovascular optimization prior to LT, prevent futile LT in those with advanced CVD beyond the stage of optimization, and thereby use the finite resources prudently.

The Unmasking Effect: Propofol-Induced Brugada Pattern in a Critically Ill Patient

Brugada syndrome is a known cause of dysrhythmias and sudden cardiac death. It is linked to mutations in myocardial sodium channel leading to hyperexcitable cardiac myocytes. The use of this sedative has been linked to the development of inducible Brugada via blockade of sodium currents in cardiac myocytes. Although propofol is usually avoided in patients with known Brugada syndrome, some patients might have undiagnosed Brugada syndrome and thus are at risk for complications. We present a case of propofol induced Brugada in a critically ill patient.

Preoperative evaluation of geriatric patients undergoing liver transplantation

PURPOSE OF REVIEW

As the population of the world is aging the number of geriatric patients undergoing liver transplantation (LT) is also increasing. They pose a unique challenge for the caregivers, as they have age-related physiological changes, multiple comorbidities and cirrhosis-related pathologies.

RECENT FINDINGS

Twenty-two percent of patients who undergo LT are older than 65 years. Many patients suffer from nonalcoholic steatohepatitis (NASH), hepatocellular carcinoma and hepatitis-C virus. Incidence of NASH tends to increase with age, obesity, diabetes and metabolic syndrome. Elderly patients require comprehensive cognitive, cardiac and pulmonary evaluation prior to LT. Cirrhotic cardiomyopathy, hepatopulmonary syndrome, portopulmonary hypertension and frailty are of specific concern.

SUMMARY

Proportion of elderly patients who are undergoing LT continues to increase. These patients require comprehensive cardiopulmonary and frailty evaluation. Consensus-based practice advisories need to be developed to standardize preoperative evaluation of geriatric patients awaiting LT.

How will NAFLD change the liver transplant landscape in the 2020s?

Liver steatosis is the hepatic manifestation of the metabolic syndrome, and is now the leading cause of chronic liver disease worldwide. The treatment of metabolic cirrhosis with liver failure and/or hepatocellular carcinoma is liver transplantation (LT). During the past decade, metabolic cirrhosis represented an increasing cause for LT, especially in the United States. At listing, patients with metabolic cirrhosis are older, with numerous cardiovascular (CV) and renal comorbidities, and this requires multidisciplinary pre-transplant assessment. After LT, 5-year survival is similar to other indications. The leading causes of death are infectious, cancers and CV. The recurrence of the initial disease is very frequent, and a significant part of the patients progress towards graft cirrhosis. No specific immunosuppressive regimen is recommended, but the toxicity profiles must probably be taken into account. In these patients, the only etiological treatment is that of obesity, in the absence of specific therapy for non-alcoholic steatohepatitis. The place of bariatric surgery has to be defined, probably sleeve gastrectomy, in a stable patient, 6-12 months after LT.

Cardiac evaluation of the kidney or liver transplant candidate

PURPOSE OF REVIEW

As the field of transplant has advanced, cardiac events have become the leading cause of morbidity and mortality after liver and kidney transplantation ahead of graft failure and infection. This trend has been bolstered by the transplantation of older and sicker patients who have a higher burden of cardiovascular risk factors, accentuating the need to determine which patients should undergo more extensive cardiac evaluation prior to transplantation.

RECENT FINDINGS

Computed tomography coronary angiography with or without coronary artery calcium scoring is now preferred over stress imaging in most transplant candidates for assessment of coronary artery disease. Assessment of cardiac structure and function using transthoracic echocardiography with tissue doppler imaging and strain imaging is recommended, particularly in liver transplant candidates who are at high risk of cirrhotic cardiomyopathy, for which new diagnostic criteria were recently published in 2019.

SUMMARY

Cardiac evaluation of liver and kidney transplant candidates requires a global assessment for both short and long-term risk for cardiac events. Imaging of cardiac structure and function using transthoracic echocardiography with tissue doppler imaging and strain imaging is recommended. Risk stratification should consider both the anatomic and functional consequences of coronary artery disease in transplant candidates.

VIDEO ABSTRACT

http://links.lww.com/MOT/A27.

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.

Analogies and differences between cirrhotic cardiomyopathy and hepatopulmonary syndrome

Cirrhotic cardiomyopathy and hepatopulmonary syndrome are two quite frequent clinical entities that may complicate the course of liver cirrhosis. The common pathophysiological origin and the same clinical presentation make them difficult to compare. Cirrhotic cardiomyopathy and hepatopulmonary syndrome may start with dyspnea and breathlessness but the former is characterized by a chronic cardiac dysfunction and the latter by a defect of oxygenation due to pulmonary shunts formation. The focus is to differentiate them as soon as possible since the treatment is different until the patient undergoes liver transplant that is the real unique cure for them.