Intraoperative Cardiac Arrest During Adult Liver Transplantation: Incidence and Risk Factor Analysis From 7 Academic Centers in the United States

Cardiovascular disease assessment and management in liver transplantation

The prevalence and mortality related to end-stage liver disease (ESLD) continue to rise globally. Liver transplant (LT) recipients continue to be older and have inherently more comorbidities. Among these, cardiac disease is one of the three main causes of morbidity and mortality after LT. Several reasons exist including the high prevalence of associated risk factors, which can also be attributed to the rise in the proportion of patients undergoing LT for metabolic dysfunction-associated steatohepatitis (MASH). Additionally, as people age, the prevalence of now treatable cardiac conditions, including coronary artery disease (CAD), cardiomyopathies, significant valvular heart disease, pulmonary hypertension, and arrhythmias rises, making the need to treat these conditions critical to optimize outcomes. There is an emerging body of literature regarding CAD screening in patients with ESLD, however, there is a paucity of strong evidence to support the guidance regarding the management of cardiac conditions in the pre-LT and perioperative settings. This has resulted in significant variations in assessment strategies and clinical management of cardiac disease in LT candidates between transplant centres, which impacts LT candidacy based on a transplant centre's risk tolerance and comfort level for caring for patients with concomitant cardiac disease. Performing a comprehensive assessment and understanding the potential approaches to the management of ESLD patients with cardiac conditions may increase the acceptance of patients, who appear too complex, but rather require extra evaluation and may be reasonable candidates for LT. The unique physiology of ESLD can profoundly influence preoperative assessment, perioperative management, and outcomes associated with underlying cardiac pathology, and requires a thoughtful multidisciplinary approach. The strategies proposed in this manuscript attempt to review the latest expert experience and opinions and provide guidance to practicing clinicians who assess and treat patients being considered for LT. These topics also highlight the gaps that exist in the comprehensive care of LT patients and the need for future investigations in this field.

Causes of Perioperative Cardiac Arrest: Mnemonic, Classification, Monitoring, and Actions

Perioperative cardiac arrest (POCA) is a catastrophic complication that requires immediate recognition and correction of the underlying cause to improve patient outcomes. While the hypoxia, hypovolemia, hydrogen ions (acidosis), hypo-/hyperkalemia, and hypothermia (Hs) and toxins, tamponade (cardiac), tension pneumothorax, thrombosis (pulmonary), and thrombosis (coronary) (Ts) mnemonic is a valuable tool for rapid differential diagnosis, it does not cover all possible causes leading to POCA. To address this limitation, we propose using the preload-contractility-afterload-rate and rhythm (PCARR) construct to categorize POCA, which is comprehensive, systemic, and physiologically logical. We provide evidence for each component in the PCARR construct and emphasize that it complements the Hs and Ts mnemonic rather than replacing it. Furthermore, we discuss the significance of utilizing monitored variables such as electrocardiography, pulse oxygen saturation, end-tidal carbon dioxide, and blood pressure to identify clues to the underlying cause of POCA. To aid in investigating POCA causes, we suggest the Anesthetic care, Surgery, Echocardiography, Relevant Check and History (A-SERCH) list of actions. We recommend combining the Hs and Ts mnemonic, the PCARR construct, monitoring, and the A-SERCH list of actions in a rational manner to investigate POCA causes. These proposals require real-world testing to assess their feasibility.

Perioperative Considerations in Older Kidney and Liver Transplant Recipients: A Review

With the growth of the older adult population, the number of older adults waitlisted for and undergoing kidney and liver transplantation has increased. Transplantation is an important and definitive treatment for this population. We present a contemporary review of the unique preoperative, intraoperative, and postoperative issues that patients older than 65 y face when they undergo kidney or liver transplantation. We focus on geriatric syndromes that are common in older patients listed for kidney or liver transplantation including frailty, sarcopenia, and cognitive dysfunction; discuss important considerations for older transplant recipients, which may impact preoperative risk stratification; and describe unique challenges in intraoperative and postoperative management for older patients. Intraoperative challenges in the older adult include using evidence-based best anesthetic practices, maintaining adequate perfusion pressure, and using minimally invasive surgical techniques. Postoperative concerns include controlling acute postoperative pain; preventing cardiovascular complications and delirium; optimizing immunosuppression; preventing perioperative kidney injury; and avoiding nephrotoxicity and rehabilitation. Future studies are needed throughout the perioperative period to identify interventions that will improve patients' preoperative physiologic status, prevent postoperative medical complications, and improve medical and patient-centered outcomes in this vulnerable patient population.

Incidence, Outcomes, and Risk Factors of Intraoperative Cardiac Arrest During Orthotopic Liver Transplantation

BACKGROUND

Intraoperative cardiac arrest (ICA) during liver transplantation (LT) is a rare surgical complication that results in devastating outcomes. Moreover, previous worldwide studies have found inconsistencies in the risk factors associated with ICA in LT.

METHODS

This was a retrospective cohort study of adult patients who underwent LT between January and October 2021 at Siriraj Hospital, a tertiary care hospital. The incidence of ICA and outcomes of patients who experienced ICA were examined. Risk factors associated with ICA were investigated as a secondary objective.

RESULTS

Among 342 patients, the incidence of ICA was 3.5% (95% CI 1.8%-6.1%). Of these, 33.3% died intraoperatively. Among patients with ICA, 41.7% died within 30 days, compared with only 7.6% in those without ICA (P = .002). Moreover, the in-hospital mortality rate of those with ICA was 58.3%, which was significantly higher than that of those without ICA (9.7%, P < .001). However, 41.7% of patients with ICA were discharged alive with long-term survival. Because ICA is a rare event, we found only 2 independent factors significantly associated with ICA. These factors include intraoperative temperature below 35°C, with an odds ratio (OR) of 6.07 (95% CI:1.32-27.88, P = .02) and elevated intraoperative serum potassium, with an OR of 4.57 (95% CI:2.15-9.67, P < .001).

CONCLUSIONS

ICA is associated with high perioperative and in-hospital mortality. However, our findings suggest that with effective management of ICA, more than 40% of these patients could be discharged with excellent long-term outcomes. Hypothermia and hyperkalemia were independent risk factors significantly associated with ICA.

Hemodynamic monitoring in liver transplantation 'the hemodynamic system'

PURPOSE OF REVIEW

The purpose of this article is to provide a comprehensive review of hemodynamic monitoring in liver transplantation.

RECENT FINDINGS

Radial arterial blood pressure monitoring underestimates the aortic root arterial blood pressure and causes excessive vasopressor and worse outcomes. Brachial and femoral artery monitoring is well tolerated and should be considered in critically ill patients expected to be on high dose pressors. The pulmonary artery catheter is the gold standard of hemodynamic monitoring and is still widely used in liver transplantation; however, it is a highly invasive monitor with potential for serious complications and most of its data can be obtained by other less invasive monitors. Rescue transesophageal echocardiography relies on few simple views and should be available as a standby to manage sudden hemodynamic instability. Risk of esophageal bleeding from transesophageal echocardiography in liver transplantation is the same as in other patient populations. The arterial pulse waveform analysis based cardiac output devices are minimally invasive and have the advantage of real-time beat to beat monitoring of cardiac output. No hemodynamic monitor can improve clinical outcomes unless integrated into a goal-directed hemodynamic therapy. The hemodynamic monitoring technique should be tailored to the patient's medical status, surgical technique, and the anesthesiologist's level of expertise.

SUMMARY

The current article provides a review of the current hemodynamic monitoring systems and their integration in goal-directed hemodynamic therapy.

Utility of transesophageal echocardiography during orthotopic liver transplantation: A narrative review

Orthotopic liver transplantation (OLT) is the standard of care for patients suffering from end stage liver disease (ESLD). This is a high-risk procedure with the potential for hemorrhage, large shifts in preload and afterload, and release of vasoactive mediators that can have profound effects on hemodynamic equilibrium. In addition, patients with ESLD can have preexisting coronary artery disease, cirrhotic cardiomyopathy, porto-pulomary hypertension and imbalanced coagulation. As cardiovascular involvement is invariable and patient are at an appreciable risk of intraoperative cardiac arrest, Trans esophageal echocardiography (TEE) is increasingly becoming a routinely utilized monitor during OLT in patients without contraindications to its use. A comprehensive TEE assessment performed by trained operators provides a wealth of information on baseline cardiac function, while a focused study specific for the ESLD patients can help in prompt diagnosis and treatment of critical events. Future studies utilizing TEE will eventually optimize examination safety, quality, permit patient risk stratification, provide intraoperative guidance, and allow for evaluation of graft vasculature.

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.

A randomized-controlled trial of ischemia-free liver transplantation for end-stage liver disease

BACKGROUND & AIMS

Ischemia-reperfusion injury (IRI) has thus far been considered as an inevitable component of organ transplantation, compromising outcomes, and limiting organ availability. Ischemia-free organ transplantation is a novel approach designed to avoid IRI, with the potential to improve outcomes.

METHODS

In this randomized-controlled clinical trial, recipients of livers from donors after brain death were randomly assigned to receive either an ischemia-free or a 'conventional' transplant. The primary endpoint was the incidence of early allograft dysfunction. Secondary endpoints included complications related to graft IRI.

RESULTS

Out of 68 randomized patients, 65 underwent transplants and were included in the analysis. 32 patients received ischemia-free liver transplantation (IFLT), and 33 received conventional liver transplantation (CLT). Early allograft dysfunction occurred in two recipients (6%) randomized to IFLT and in eight (24%) randomized to CLT (difference -18%; 95% CI -35% to -1%; p = 0.044). Post-reperfusion syndrome occurred in three recipients (9%) randomized to IFLT and in 21 (64%) randomized to CLT (difference -54%; 95% CI -74% to -35%; p <0.001). Non-anastomotic biliary strictures diagnosed with protocol magnetic resonance cholangiopancreatography at 12 months were observed in two recipients (8%) randomized to IFLT and in nine (36%) randomized to CLT (difference, -28%; 95% CI -50% to -7%; p = 0.014). The comprehensive complication index at 1 year after transplantation was 30.48 (95% CI 23.25-37.71) in the IFLT group vs. 42.14 (95% CI 35.01-49.26) in the CLT group (difference -11.66; 95% CI -21.81 to -1.51; p = 0.025).

CONCLUSIONS

Among patients with end-stage liver disease, IFLT significantly reduced complications related to IRI compared to a conventional approach.

CLINICAL TRIAL REGISTRATION

chictr.org. ChiCTR1900021158.

IMPACT AND IMPLICATIONS

Ischemia-reperfusion injury has thus far been considered as an inevitable event in organ transplantation, compromising outcomes and limiting organ availability. Ischemia-free liver transplantation is a novel approach of transplanting donor livers without interruption of blood supply. We showed that in patients with end-stage liver disease, ischemia-free liver transplantation, compared with a conventional approach, led to reduced complications related to ischemia-reperfusion injury in this randomized trial. This new approach is expected to change the current practice in organ transplantation, improving transplant outcomes, increasing organ utilization, while providing a clinical model to delineate the impact of organ injury on alloimmunity.

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

BACKGROUND

We sought to establish consensus on the essential skills, knowledge, and attributes that a liver transplant (LT) anesthesiologist should possess in a bid to help guide the further training process.

METHODS

Consensus was achieved via a modified Delphi methodology, surveying 15 identified international experts in the fields of LT anesthesia and critical care.

RESULTS

Key competencies were identified in preoperative management and optimization of a potential LT recipient; intraoperative management, including hemodynamic monitoring; coagulation and potential crisis management; and postoperative intensive and enhanced recovery care.

CONCLUSIONS

This article provides an essential guide to competency-based training of an LT anesthesiologist.

Management of Intraoperative Cardiac Arrest

Perioperative arrests are both uncommon and heterogeneous and have not been described or studied to the same extent as cardiac arrest in the community. These crises are usually witnessed, frequently anticipated, and involve a rescuer physician with knowledge of the patient's comorbidities and coexisting anesthetic or surgically related pathophysiology ultimately leading to better outcomes. This article reviews the most probable causes of intraoperative arrest and their management.

Planned Extracorporeal Life Support Employment during Liver Transplantation: The Potential of ECMO and CRRT as Preventive Therapies-Case Reports and Literature Review

Liver Transplantation (LT) has become the gold standard treatment for End-Stage Liver Disease (ESLD). One of the main strategies to manage life-threatening complications, such as cardio-respiratory failure, is Extracorporeal Membrane Oxygenation (ECMO) in the peri-transplantation period, with different configurations of the technique and in combination with other extracorporeal care devices such as Continuous Renal Replacement Therapy (CRRT). This retrospective study includes three clinical cases of planned ECMO support strategies in LT and evaluates their application compared with current literature exploring PubMed/Medline. The three LT supported with ECMO and CRRT were performed at IRCCS Polyclinic S. Orsola-Malpighi, Bologna. All three cases of patients with compromised organ function analysed produced positive outcomes. The planned use of ECMO and CRRT support in peri-transplantation has allowed the patients to overcome contraindications and successfully undergo LT. In recent years, only a few reports have documented successful LT outcomes performed with intraoperative ECMO in critically ESLD patients. However, the management of LT with ECMO and/or CRRT assistance is an emerging challenge, with the need for more published evidence on this topic to guide treatment choices in patients with severe, acute and reversible respiratory and cardiovascular failure after LT.

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

INTRODUCTION

In 2013, a new liver transplant allocation policy (Share 35) aimed to reduce waitlist-mortality was introduced in the United States. Regional organ sharing for recipients with a MELD score of ≥35 was prioritized over local allocation to those with lower MELD scores. Our aim was to assess the changes in perioperative mortality following the introduction of Share 35 as well as changes in patients' short-term 7-day survival, patients discharged alive and 1-year survival. Analyses were also carried out for the subgroups of patients with MELD scores ≥ and < 35.

METHODS

We used data from the Scientific Registry of Transplant Recipients and included liver transplants between March 2002 and December 2018 in this retrospective cohort study. Perioperative mortality was defined as death during and within two days of liver transplant. We used robust interrupted time series analyses to evaluate the impact of Share 35 on mortality.

RESULTS

We included 90 002 liver transplants in our analysis and observed a decreasing trend in perioperative mortality over time (-.061 deaths per 1000 cases per month, 95% CI -.084 to -.037, p < .001). Share 35 was not associated with a change in perioperative mortality (p = .33), short-term 7-day survival (p = .48), survival to discharge (p = .56), or 1-year survival (p = .27).

CONCLUSIONS

Prioritizing sicker recipients with a MELD score ≥35 for liver transplantation was not associated with a change in postoperative mortality.

Emerging Evidence on Coronary Heart Disease Screening in Kidney and Liver Transplantation Candidates: A Scientific Statement From the American Heart Association: Endorsed by the American Society of Transplantation

Coronary heart disease is an important source of mortality and morbidity among kidney transplantation and liver transplantation candidates and recipients and is driven by traditional and nontraditional risk factors related to end-stage organ disease. In this scientific statement, we review evidence from the past decade related to coronary heart disease screening and management for kidney and liver transplantation candidates. Coronary heart disease screening in asymptomatic kidney and liver transplantation candidates has not been demonstrated to improve outcomes but is common in practice. Risk stratification algorithms based on the presence or absence of clinical risk factors and physical performance have been proposed, but a high proportion of candidates still meet criteria for screening tests. We suggest new approaches to pretransplantation evaluation grounded on the presence or absence of known coronary heart disease and cardiac symptoms and emphasize multidisciplinary engagement, including involvement of a dedicated cardiologist. Noninvasive functional screening methods such as stress echocardiography and myocardial perfusion scintigraphy have limited accuracy, and newer noninvasive modalities, especially cardiac computed tomography-based tests, are promising alternatives. Emerging evidence such as results of the 2020 International Study of Comparative Health Effectiveness With Medical and Invasive Approaches-Chronic Kidney Disease trial emphasizes the vital importance of guideline-directed medical therapy in managing diagnosed coronary heart disease and further questions the value of revascularization among asymptomatic kidney transplantation candidates. Optimizing strategies to disseminate and implement best practices for medical management in the broader end-stage organ disease population should be prioritized to improve cardiovascular outcomes in these populations.

Proceedings of the 26th Annual Virtual Congress of the International Liver Transplantation Society

After a 1-y absence due to the coronavirus disease 2019 pandemic, the 26th Annual Congress of the International Liver Transplantation Society was held from May 15 to 18, 2021, in a virtual format. Clinicians and researchers from all over the world came together to share their knowledge on all the aspects of liver transplantation (LT). Apart from a focus on LT in times of coronavirus disease 2019, featured topics of this year's conference included infectious diseases in LT, living donation, machine perfusion, oncology, predictive scoring systems and updates in anesthesia/critical care, immunology, radiology, pathology, and pediatrics. This report presents highlights from invited lectures and a review of the select abstracts. The aim of this report, generated by the Vanguard Committee of International Liver Transplantation Society, is to provide a summary of the most recent developments in clinical practice and research in LT.

Perioperative management of adult living donor liver transplantation: Part 1 - recipients

Living donor liver transplantation was first developed to mitigate the limited access to deceased donor organs in Asia in the 1990s. This alternative liver transplantation option has become an established and widely practiced transplantation method for adult patients suffering from end-stage liver disease. It has successfully addressed the shortage of deceased donors. The Society for the Advancement of Transplant Anesthesia and the Korean Society of Transplant Anesthesia jointly reviewed published studies on the perioperative management of live donor liver transplant recipients. The review aims to offer transplant anesthesiologists and critical care physicians a comprehensive overview of the perioperative management of adult live liver transplantation recipients. We feature the status, outcomes, surgical procedure, portal venous decompression, anesthetic management, prevention of acute kidney injury, avoidance of blood transfusion, monitoring and therapeutic strategies of hemodynamic derangements, and Enhanced Recovery After Surgery protocols for liver transplant recipients. This article is protected by copyright. All rights reserved.

Preliminary experience with continuous right ventricular pressure and transesophageal echocardiography monitoring in orthotopic liver transplantation

Background

Despite increasing attention in the cardiac anesthesiology literature, continuous measurement of right ventricular pressure using a pulmonary artery catheter has not been described in orthotopic liver transplantation, despite similarities in the anesthetic approach to the two populations. We describe our preliminary experience with this technique in orthotopic liver transplantation, and by combining various derived measures with trans-esophageal echocardiography, make some early observations regarding the response of these measures of right ventricular function during the procedure.

Methods

In this case series, ten patients (five men and five women) undergoing orthotopic liver transplantation in our institution had their surgeries performed while monitored with a pulmonary artery catheter with continuous right ventricular port transduction and trans-esophageal echocardiography. We recorded various right ventricular waveform (early-to-end diastolic pressure difference, right ventricular outflow tract gradient, right ventricular dP/dT and right ventricular end-diastolic pressure) and echocardiographic (right ventricular fractional area change, tricuspid annular plane systolic excursion, right ventricular lateral wall strain) and described their change relative to baseline at timepoints five minutes before and after portal vein reperfusion, immediately after hepatic artery reperfusion and on abdominal closure.

Results

Except for tricuspid annular plane systolic excursion at five minutes prior to reperfusion (mean −0.8 cm; 95% CI−1.4, –0.3; p = 0.007), no echocardiographic metric was statistically significantly different at any timepoint relative to baseline. In contrast, changes in right ventricular outflow tract gradient and right ventricular dP/dt were highly significant at multiple timepoints, generally peaking immediately before or after reperfusion before reducing, but not returning to baseline in the neohepatic phase. Nine of 10 participants in this series demonstrated a degree of dynamic right ventricular outflow tract obstruction, which met criteria for hemodynamic significance (> 25 mmHg) in two participants. These changes were not materially affected by cardiac index.

Conclusions

Dynamic right ventricular outflow tract obstruction of varying severity appears common in patients undergoing orthotopic liver transplantation. These results are hypothesis generating and will form the basis of future prospective research.

Preoperative echocardiography as a prognostic tool for liver transplant in patients with hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) presents with a hypertrophied left ventricle (LV). It is often associated with LV outflow tract obstruction (LVOTO) and a risk for sudden death. This study aimed to describe outcomes of patients with HCM who underwent liver transplant (LT).

METHODS

A retrospective review was conducted for patients diagnosed with HCM undergoing LT. Patient characteristics, preoperative echocardiography results, HCM risk of sudden cardiac death prediction model score, and 5-year mortality were examined. A univariable Cox proportional hazards model was used to evaluate the association between risk factors and 5-year mortality. All tests were two-sided with the alpha level set at .05.

RESULTS

Twenty-nine patients were included in the analysis. Six patients (21%) had a perioperative cardiopulmonary complication. The 5-year survival rate was 61% (95% CI, 45-82). The analyzed risk factors showed that 5-year post-LT survival was significantly predicted by maximal LV outflow tract gradient at rest > 60 mmHg (hazard ratio, 1.04 [95% CI, 1.01-1.06]).

CONCLUSIONS

Preoperative LV outflow tract resting gradient > 60 mmHg was associated with 5-year post-LT mortality. The results suggest the severity of LVOTO identified by echocardiography is a prognostic tool for patients with HCM after LT.

Sex differences in disease presentation, surgical and oncological outcome of liver resection for primary and metastatic liver tumors-A retrospective multicenter study

Background

Sex differences are becoming of rising interest in many fields of medicine. It remains unknown whether sex has a role in postoperative and long-term outcome after hepatic resection (HR). The aim of this study was to investigate sex differences in disease presentation, surgical and oncological outcome after curative HR.

Methods

Retrospective analysis of 1010 patients who underwent HR between 2005 and 2018 at two tertiary hospitals in Austria. Demographics and survival data were obtained from a prospectively maintained database. Univariate analysis was used to identify sex differences for the entire cohort and for sub-cohorts. Disease-free- and overall survival was assessed by the Kaplan-Meier estimate and results were compared by log-rank tests.

Results

436 females and 574 males were analyzed. Women were younger (p<0.001), had less liver cirrhosis (p<0.001), cardiac comorbidities (p<0.001), diabetes (28 (p<0.001) and obesity (p<0.001). Type of HR and surgical management did not vary by sex. Ninety-day morbidity (p = 0.179) and -mortality (p = 0.888) were comparable. In patients with malignant disease, no differences in disease-free- and overall survival was observed, neither for the entire cohort nor for the subgroups according to tumor entity or type of resection. Only in HCC patients, females showed an inferior OS (p = 0.029).

Conclusion

This study delivers new insights on the impact of sex differences in liver surgery. Despite the fact that male patients have a higher incidence of preoperative morbidities, we did not observe specific disparities in terms of immediate postoperative as well as long term oncological outcome between sexes.