Intraoperative pulmonary embolism and intracardiac thrombosis complicating liver transplantation: a systematic review

Coagulation management during liver transplantation: monitoring and decision making for hemostatic interventions

PURPOSE OF REVIEW

Rebalanced hemostasis describes the precarious balance of procoagulant and antithrombotic proteins in patients with severe liver failure. This review is aimed to discuss currently available coagulation monitoring tests and pertinent decision-making process for plasma coagulation factor replacements during liver transplantation (LT).

RECENT FINDINGS

Contemporary viscoelastic coagulation monitoring systems have demonstrated advantages over conventional coagulation tests in assessing the patient's coagulation status and tailoring hemostatic interventions. There is increasing interest in the use of prothrombin complex and fibrinogen concentrates, but it remains to be proven if purified factor concentrates are more efficacious and safer than allogeneic hemostatic components. Furthermore, the decision to use antifibrinolytic therapy necessitates careful considerations given the risks of venous thromboembolism in severe liver failure.

SUMMARY

Perioperative hemostatic management and thromboprophylaxis for LT patients is likely to be more precise and patient-specific through a better understanding and monitoring of rebalanced coagulation. Further research is needed to refine the application of these tools and develop more standardized protocols for coagulation management in LT.

Intracardiac thrombosis and pulmonary thromboembolism during liver transplantation: A systematic review and meta-analysis

Intracardiac thrombosis and/or pulmonary thromboembolism (ICT/PE) is a rare but devastating complication during liver transplantation. Its pathophysiology remains poorly understood, and successful treatment remains a challenge. This systematic review summarizes the available published clinical data regarding ICT/PE during liver transplantation. Databases were searched for all publications reporting on ICT/PE during liver transplantation. Data collected included its incidence, patient characteristics, the timing of diagnosis, treatment strategies, and patient outcomes. This review included 59 full-text citations. The point prevalence of ICT/PE was 1.42%. Thrombi were most often diagnosed during the neohepatic phase, particularly at allograft reperfusion. Intravenous heparin was effective in preventing early-stage thrombus from progressing further and restoring hemodynamics in 76.32% of patients it was utilized for; however, the addition of tissue plasminogen activator or sole use of tissue plasminogen activator offered diminishing returns. Despite all resuscitation efforts, the in-hospital mortality rate of an intraoperative ICT/PE was 40.42%, with nearly half of these patients dying intraoperatively. The results of our systematic review are an initial step for providing clinicians with data that can help identify higher-risk patients. The clinical implications of our results warrant the development of identification and management strategies for the timely and effective treatment of these tragic occurrences during liver transplantation.

Liver Transplantation from a Human Leukocyte Antigen-Matched Sibling Donor: Effectiveness of Direct-Acting Antiviral Therapy against Hepatitis C Virus Infection

Through living-donor liver transplantation (LDLT) from a human leukocyte antigen (HLA)-matched sibling donor, it may be possible to stop the use of immunosuppressants. It is possible that acute antibody-mediated rejection and chronic active antibody-mediated rejection through the positivity of donor-specific anti-HLA antibodies and/or T cell-mediated rejection may affect the prognosis of liver transplantation. The etiologies of liver diseases of the recipient may also affect the post-transplantation course. Herein, we report on the successful re-treatment with direct-acting antiviral (DAA) therapy against hepatitis C virus (HCV) infection in a patient who underwent a LDLT from HLA-matched sibling donor. After liver transplantation for HCV-related liver diseases, it is easy for HCV to re-infect the graft liver under a lack of immunosuppressants. DAA therapy against HCV re-infection immediately after transplantation should be commenced, and it is important to eradicate HCV for better prognosis of the recipients in LDLT for HCV-related liver diseases.

2021 Clinical Update in Liver Transplantation

In 2021, the United States performed 9,236 liver transplantations, an increase of 3.7% from 2020. As the specialty of transplant anesthesiologist continues to grow, so does the body of evidence-based research to improve patient care. New technology in organ preservation offers the possibility of preserving marginal organs for transplant or improving the graft for transplantation. The sequalae of end-stage liver disease have wide-ranging consequences that affect neurologic outcomes of patients both during and after transplantation that anesthesiologists should monitor. Obesity presents several challenges for anesthesiologists. As an increasing number of patients with nonalcoholic steatohepatitis are listed for transplant, managing their multiple comorbidities can be challenging. Finally, the rebalanced hemostasis of end-stage liver disease can cause both bleeding and thrombus. Often, bleeding risks predominate as a concern, but anesthesiologists should be aware of risks of intracardiac thrombus and review therapeutic options for prevention and treatment.

Intraoperative intracardiac thrombus in liver transplantation: A 9-year retrospective review focusing on treatment and outcomes

This study characterizes incidence and outcomes surrounding intracardiac thrombosis (ICT) during liver transplantation over 9 years at a single center before and after the routine use of transesophageal echocardiography (TEE). Adult liver transplantation patients from 2011 to 2020 were divided into eras based on routine TEE use. ICTs were identified by querying anesthetic records for search terms. Descriptive statistics included counts and proportions for baseline recipient, donor, intraoperative, and postoperative characteristics. Outcome data were based on date of hospital discharge and date of death. The incidence of ICT increased in the TEE era (2016-2020) compared with the pre-TEE era (2011-2015; 3.7% [25/685] vs. 1.9% [9/491]; p < 0.001). Patients with ICT had significantly higher Model for End-Stage Liver Disease-sodium (MELD-Na) scores, pretransplant hospitalization, malignancy, drug-induced liver injury, hypertension, deep vein thrombosis, reperfusion syndrome, transfused platelets and cryoprecipitate, and use of hemostatic medications. A higher proportion of patients in the ICT group underwent simultaneous liver-kidney transplantation. The patients with ICT were similar, except patients in the pre-TEE era had higher MELD-Na scores and incidences of hepatitis C virus and lower incidences of encephalopathy. In the pre-TEE era, all ICTs presented as intraoperative cardiac arrest, and the 30-day mortality in the setting of ICT was 66.7% (6/9). During the TEE era, 80% of ICTs were diagnosed incidentally or attributed to hemodynamic instability (p = 0.002). The 30-day mortality rate was 36% (9/25) in the TEE era (p = 0.25). ICT incidence increased in the TEE era, yet the mortality rate was lower, suggesting that routine intraoperative TEE may lead to the early detection of ICT prior to hemodynamic collapse.

Risks and Outcomes of Perioperative Pulmonary Embolism in Major Surgeries: A Population-Based Study

PURPOSE

Perioperative pulmonary embolism (PE) is a significant cardiovascular complication in many surgeries. This study aimed to investigate the risks and outcomes of perioperative PE in major surgery.

METHODS

Discharge records of the Nationwide Readmission Database from 2010 to 2015 were extracted and analyzed. Length of stay, charges, death, and 30-day hospital readmission rate were compared for patients with and without perioperative PE. In addition, surgery-specific risk factors and therapies associated with PE were explored in a multivariable model.

FINDINGS

A total of 12,376,153 hospitalizations for major surgeries were involved, and perioperative PE occurred in 22,676 hospitalizations (0.18%). The length of stay, charges, rate of death, and 30-day hospital readmission were higher in patients with perioperative PE than in those without perioperative PE. Respiratory (odds ratios [OR], 2.09; 95% CI, 1.89-2.3), cardiovascular (OR, 1.62; 95% CI, 1.51-1.73), and musculoskeletal (OR, 1.22; 95% CI, 1.1-1.29) surgeries were risk factors for the occurrence of perioperative PE. In patients with perioperative PE, respiratory surgery was a risk factor for death (OR, 1.48; 95% CI, 1.10-2.00), whereas gynecologic/obstetric surgery was a protective factor for 30-day readmission (OR, 0.30; 95% CI, 0.10-0.88). Regarding therapy for perioperative PE, thrombolytic therapy (OR, 1.74; 95% CI, 1.26-2.42) and embolectomy (OR, 3.60; 95% CI, 2.35-5.51) were risk factors for death.

IMPLICATIONS

Respiratory, cardiovascular, and musculoskeletal surgeries were risk factors for the occurrence of perioperative PE and death. Future research on precise models to predict PE in major surgeries is needed for appropriate interventions to improve outcomes of perioperative PE.

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

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

The Challenging Management of an Intracardiac Thrombus in a Liver Transplant Patient at the Reperfusion Phase: A Case Report and Brief Literature Review

The exact origin of intracardiac thrombi formation during orthotopic liver transplant remains unknown. The altered balance between hypercoagulability, hypocoagulation, and endothelial dysfunction associated with end-stage liver disease is thought to play a pivotal role. Venous stasis, vascular clamping, and reperfusion could also contribute to clot formation. The incidence of intracardiac thrombi formation stands at 4.2%, associated with a mortality rate of 45.5%, and to date, no consensus exists regarding the best way to treat this complication. Intraoperative transesophageal echocardiography is the only effective method for diagnosing intracardiac thrombi formation early, while point-of-care coagulation testing could guide the coagulation management potentially improving patient outcomes.

Intraoperative development of pulmonary thromboembolism in a bedridden patient owing to a pelvic bone fracture with negative preoperative computed tomography pulmonary angiographic findings: A case report

RATIONALE

Pulmonary thromboembolism (PTE) is a potentially life-threatening condition with high morbidity and mortality, and computed tomographic pulmonary angiography (CTPA) is an important diagnostic tool for patients in whom PTE is suspected; however, intraoperative PTE is very difficult to diagnose and often has a rapid clinical course. We experienced a case of intraoperative PTE with persistent tachycardia refractory to conventional treatments despite negative preoperative CTPA findings.

PATIENT CONCERNS

A 53-year-old man with a pelvic bone fracture who had been on bed rest for 10 days underwent open reduction and internal fixation under general anesthesia. He remained tachycardic (heart rate of 120 beats/min) despite treatments with fluid resuscitation, analgesics, and beta-blockers.

DIAGNOSES

Preoperative CTPA, computed tomography (CT) venography, and transthoracic echocardiography showed no signs of deep vein thrombosis and PTE. However, the levels of D-dimer were elevated. After the start of the surgery, tachycardia (heart rate between 100 and 110 beats/min) could not be treated with fluid resuscitation. Systolic blood pressure was maintained between 90 and 100 mm Hg using continuous infusion of phenylephrine. Ninety minutes after the surgery, systolic and diastolic blood pressures suddenly dropped from 100/60 to 30/15 mm Hg with a decrease in end-tidal carbon dioxide concentration from 29 to 13 mm Hg and development of atrial fibrillation. Arterial blood gas analysis revealed hypercapnia. Under the suspicion of PTE, cardiopulmonary resuscitation (CPR) was immediately initiated. Three CPR cycles raised the blood pressure back to 90/50 mm Hg with sinus tachycardia (115 beats/min). Transesophageal echocardiography showed right ventricular dysfunction and paradoxical septal motion. However, emboli were not found. Postoperative chest CT revealed massive PTE in both pulmonary arteries.

INTERVENTIONS

Immediately, surgical embolectomy was performed uneventfully.

OUTCOMES

The patient was discharged from the hospital 1 month later without any complications.

LESSONS

The patient with moderate risk for PTE (heart rate > 95 beats/min and immobilization, surgery under general anesthesia, and lower limb fracture within 1 month) should be closely monitored and managed intraoperatively even if preoperative CTPA findings are negative. The development of PTE needs to be expected if tachycardia is refractory to conventional treatments.

Perioperative fatal pulmonary embolism in a pediatric liver transplant recipient

Patients with cirrhotic liver disease are in a state of fluctuating hemostatic balance. Hepatic synthetic dysfunction is commonly complicated by coagulation disorders that constitute an important parameter of most prognostic scores. The dominant feature of this dysfunction is bleeding tendencies, but cirrhotic patients may also exhibit inappropriate clotting and pro-coagulation placing them at risk for thromboembolism. We present a case of perioperative fatal pulmonary embolism in an 8-year-old patient with biliary cirrhosis secondary to drug-induced vanishing bile duct syndrome undergoing a deceased donor liver transplant. The massive pulmonary embolism occurred intra-operatively after reperfusion of the donor liver. Despite the initiation of extracorporeal membrane oxygenation, the postoperative course was complicated by bleeding and the patient expired. This unique case highlights the need for venous thromboembolism prevention by screening and prophylaxis prior to liver transplant in at least a subpopulation of pediatric patients. While the risk of thrombosis postoperatively in pediatrics patients is well known, the preoperative risk is less frequently described and deserves attention and practice changing action.

Perioperative management of patients with pulmonary hypertension undergoing non-cardiothoracic, non-obstetric surgery: a systematic review and expert consensus statement

BACKGROUND

The risk of complications, including death, is substantially increased in patients with pulmonary hypertension (PH) undergoing anaesthesia for surgical procedures, especially in those with pulmonary arterial hypertension (PAH) and chronic thromboembolic PH (CTEPH). Sedation also poses a risk to patients with PH. Physiological changes including tachycardia, hypotension, fluid shifts, and an increase in pulmonary vascular resistance (PH crisis) can precipitate acute right ventricular decompensation and death.

METHODS

A systematic literature review was performed of studies in patients with PH undergoing non-cardiac and non-obstetric surgery. The management of patients with PH requiring sedation for endoscopy was also reviewed. Using a framework of relevant clinical questions, we review the available evidence guiding operative risk, risk assessment, preoperative optimisation, and perioperative management, and identifying areas for future research.

RESULTS

Reported 30 day mortality after non-cardiac and non-obstetric surgery ranges between 2% and 18% in patients with PH undergoing elective procedures, and increases to 15-50% for emergency surgery, with complications and death usually relating to acute right ventricular failure. Risk factors for mortality include procedure-specific and patient-related factors, especially markers of PH severity (e.g. pulmonary haemodynamics, poor exercise performance, and right ventricular dysfunction). Most studies highlight the importance of individualised preoperative risk assessment and optimisation and advanced perioperative planning.

CONCLUSIONS

With an increasing number of patients requiring surgery in specialist and non-specialist PH centres, a systematic, evidence-based, multidisciplinary approach is required to minimise complications. Adequate risk stratification and a tailored-individualised perioperative plan is paramount.

An observational study of hemostatic profile during different stages of liver transplant surgery using laboratory-based tests and thromboelastography

Background:

Liver produces most of the blood coagulation factors, so it is not surprising to see a deranged coagulation profile in patients receiving liver transplants. Besides standard laboratory methods to evaluate coagulation profile, point-of-care assays are being used regularly since their results are rapidly available. However, sparse information is available on the comparability of point-of-care coagulation assays with laboratory coagulation assays in this special setting. In this study, our aim is to observe the changing hemostatic profile during different stages of liver transplant surgery using laboratory-based tests and thromboelastography (TEG).

Methods:

Fifty patients undergoing living donor liver transplantation surgery were selected. Coagulation tests (prothrombin time [PT], activated partial thromboplastin time [APTT], platelet count, and fibrinogen) and TEG were performed at various intervals during liver transplant surgeries – before induction of anesthesia, 2 h into dissection phase, 30 min into anhepatic phase, 30 min after reperfusion of homograft, postoperative – at closure of surgery, 12 h postoperative, and 24 h postoperative. Statistical analysis and Pearson correlation were performed between laboratory-based coagulation tests and TEG, and their pattern through various stages of the surgery analyzed.

Results:

Platelet count and fibrinogen have a significant positive correlation with TEG in almost all phases of liver transplant. PT and APTT have a positive correlation with TEG until uptake of new liver and predominantly negative correlation after that. However, this correlation is significant only before induction of anesthesia and anhepatic phase.

Conclusions:

TEG can be used to estimate platelet count and fibrinogen concentrations in all phases but PT and APTT only before induction and anhepatic phase of liver transplant surgery. The decision regarding transfusion of blood products should be based on a combination of the clinical assessment of surgeon and anesthesia personnel combined with results from laboratory and TEG.

Risk Factors and Outcomes of Intracardiac Thrombosis During Orthotopic Liver Transplantation

BACKGROUND

Intracardiac thrombosis incidence during orthotopic liver transplantation is estimated at 0.36% to 6.2% with mortality up to 68%. We aimed to evaluate risk factors and outcomes related to intracardiac thrombosis during orthotopic liver transplantation.

MATERIALS AND METHODS

A comprehensive retrospective data review of 388 patients who underwent orthotopic liver transplantation at an urban transplant center from January 2013 to October 2016 was obtained.

RESULTS

Six patients were found to have documented intracardiac thrombosis; 4 cases were recognized during the reperfusion stage and 1 during pre-anhepatic stage. All allografts were procured from decreased donors with a median donor age of 44 years (interquartile range, 35.25-49.75) and the cause of death was listed as cerebrovascular accident in 5 donors. Preoperative demographic, clinical, laboratory, and historical risk factors did not differ in patients with thrombosis. None had a prior history of trans-jugular intrahepatic portosystemic shunt or gastrointestinal bleeding. Three patients had renal injury, but no intraoperative hemodialysis was performed. Transesophageal echocardiographic findings included elevated pulmonary artery pressure (1/6), right ventricular strain (1/6), and pulmonary artery thrombus (1/6). Three patients died intraoperatively. Tissue plasminogen activator alone was given to 1 patient who did not survive, intravenous heparin only to 1 patient with resolution, and a combination of both was used in 2 patients with clot resolution achieved.

CONCLUSION

Cardiac thrombosis should be considered in patients having hemodynamic compromise during liver transplantation. Transesophageal echocardiography is a useful diagnostic tool. Intracardiac thrombosis treatment remains challenging; however, using both thrombolytics and heparin could achieve better results.

Acute heart failure after liver transplantation: A narrative review

Acute heart failure (AHF) is an under recognized yet potentially lethal complication after liver transplantation (LT) surgery. The increase in incidence of liver transplantation amongst high-risk patients and the leniency in the criteria for transplantation, predisposes these patients to postoperative AHF and the antecedent morbidity and mortality. The inability of conventional preoperative cardiovascular testing to accurately identify patients at risk for post-LT AHF poses a considerable challenge to clinicians caring for these patients. Even if high-risk patients are identified, there is considerable ambiguity in the candidacy for transplantation as well as optimization strategies that could potentially prevent the development of AHF in the postoperative period. The intraoperative and postoperative management of patients who develop AHF is also challenging and requires a well-coordinated multidisciplinary approach. The use of mechanical circulatory support in patients with refractory heart failure has the potential to improve outcomes but its use in this complex patient population can be associated with significant complications and requires a stringent risk-benefit analysis on a case-by-case basis.

Role of Transesophageal Echocardiography in the Diagnosis of Multi-chamber Intracardiac Thrombosis During Liver Transplantation: A Case Series

Intra-cardiac thrombosis is one of the most devastating complications during liver transplantation. In the majority of cases, ICT, followed by massive pulmonary embolism, is commonly occurring shortly after liver graft reperfusion, but it has been reported to occur at any stage of the surgery. We present a series of 3 cases of intra-cardiac thrombosis during orthotopic liver transplantation surgery, including a case of four-chamber intra-cardiac clot formation during the pre-anhepatic stage. This article represents a single-centre 14 year-long experience. Intra-operative TEE is the gold standard to diagnose intra-cardiac thrombosis, monitoring its size, location and dynamics, as well as myocardial performance and the effects of resuscitation efforts.

Massive Pulmonary Artery Thromboembolism in a Liver Transplant Recipient: Case Study and Literature Review

The hypercoagulable state in liver transplant recipients that may manifest as abnormal thrombus formation in large vessel structures, such as cardiac chambers and the pulmonary arteries, poses a substantial threat for the patient and graft survival. Massive pulmonary embolism is a rare, albeit potentially lethal, complication that may occur at any stage of liver transplant surgery. In this study, we present the case of a major perioperative thromboembolic event in a liver transplant recipient that had taken place in the early post-transplant period during the second-look surgery that was then successfully treated by catheter-directed clot removal. We will attempt to identify potential factors that may have been associated with abnormal thrombus formation.

Viscoelastic coagulation test for liver transplantation

Coagulation and transfusion management in patients undergoing liver transplantation is challenging. Proper perioperative monitoring of hemostasis is essential to predict the risk of bleeding during surgery, to detect potential causes of hemorrhage in time, and to guide hemostatic therapy. The value of conventional coagulation test is questionable in the acute perioperative setting due to their long turnaround time and the inability to adequately reflect the complex changes in hemostasis in patients with liver disease. Viscoelastic coagulation tests provide simultaneous measurement of multiple aspects of whole-blood coagulation including plasmatic coagulation and fibrinolytic factors and inhibitors that reflect most aspects of hemostasis. Coagulation initiation, mechanical clot stability, and fibrinolysis can be estimated immediately using point-of-care techniques. Therefore, viscoelastic coagulation tests including ROTEM & TEG would be useful to guide patient blood management strategy during liver transplantation.

Perioperative management of antithrombotic treatment

End-stage liver disease is characterized by multiple and complex alterations of hemostasis that are associated with an increased risk of both bleeding and thrombosis. Liver transplantation further challenges the feeble hemostatic balance of patients with decompensated cirrhosis, and the management of antithrombotic treatment during and after transplant surgery, which is particularly difficult. Bleeding was traditionally considered the major concern during and early after surgery, but it is increasingly recognized that transplant recipients may also develop thrombotic complications. Pathophysiology of hemostatic complications during and after transplantation is multifactorial and includes pre-, intra-, and postoperative risk factors. Risk stratification is important, as it helps the identification of high-risk recipients in whom antithrombotic prophylaxis should be considered. In recipients who develop thrombosis during or after surgery, prompt treatment is indicated to prevent graft failure, retransplantation, and death.

Risk Factors for Intracardiac Thrombus During Liver Transplantation

Intracardiac thrombus (ICT) is an intraoperative complication with high mortality that occurs during orthotopic liver transplantation (OLT). Patients with end-stage liver disease have compromised coagulation pathways, and when combined with stressors of surgery, thrombi can form. However, it is unknown which patients are most likely to develop ICT. We performed a retrospective cohort study of all OLT patients at our hospital from 2010 to 2017 to identify risk factors for ICT. An analysis was performed with conventional bivariate tests and logistic regression. The incidence of ICT during OLT was 4.2% (22/528) with a 45.5% (10/22) mortality. Patients who developed ICT had higher physiologic Model for End-Stage Liver Disease scores at the time of transplant (25.1 versus 32.4; P = 0.004), received grafts from donors with a higher body mass index (28.1 versus 32.2 kg/m² ; P = 0.007), and had longer intraoperative warm ischemia times (53.1 versus 67.5 minutes; P = 0.001). The odds of developing ICT were significantly lower after administration of intravenous (IV) heparin prior to inferior vena cava (IVC) clamping compared with no administration of heparin (odds ratio, 0.25; 95% confidence interval, 0.08-0.75; P = 0.01). In conclusion, the incidence of ICT at our institution is higher than previously reported, which may be explained by our routine use of transesophageal echocardiography. Although many factors associated with ICT in this study are nonmodifiable, administration of IV heparin prior to IVC cross-clamping is modifiable and was found to be protective. Further studies will be needed to confirm findings and ultimately aid in preventing these lethal events.

Impedance Aggregometry Reveals Increased Platelet Aggregation during Liver Transplantation

In patients presenting for liver transplantation, increased platelet aggregation as well as thrombocytopenia have been demonstrated, but bedside assays have not been investigated. We compared platelet aggregation in liver transplantation patients and control surgical patients using impedance aggregometry. We hypothesized that platelet activity is not altered during liver transplantation. After the allowance of the ethics committee, platelet aggregation was determined using impedance aggregometry with the activators ristocetin, adenosine diphosphate (ADP), arachidonic acid, collagen, and thrombin receptor-activating peptide (TRAP) in liver transplantation patients at four time points (start of surgery, anhepatic phase, reperfusion, end of surgery) and in control surgical patients. Moreover, platelet count was determined using a Coulter counter. To compensate for the thrombocytopenia often present in patients presenting for liver transplantation, the ratio between impedance aggregometry finding and platelet count was used. For statistical evaluation, the t-test or the Mann–Whitney U-test were used, as appropriate. Platelet aggregation ratio showed a 3.1-fold increase in liver transplantation patients (n = 37) in comparison to control surgical patients (n = 10) when ristocetin was used as the activator (p = 0.001). Moreover, an approximately twofold increase of ADP-, arachidonic acid-, collagen-, and TRAP-induced platelet aggregation ratio was determined. Platelet aggregation normalized at the end of the transplantation procedure. Impedance aggregometry revealed a markedly increased platelet aggregation in some liver transplantation patients and might be suitable to guide platelet transfusion and antiplatelet therapy.

Safety of coagulation factor concentrates guided by ROTEM™-analyses in liver transplantation: results from 372 procedures

Background

Most centres use fresh frozen plasma (FFP) based protocols to prevent or treat haemostatic disturbances during liver transplantation. In the present study, we used a rotational thrombelastometry (ROTEM™, TEM, Munich, Germany) guided haemostasis management with fibrinogen concentrates, prothrombin complex concentrates (PCC), platelet concentrates and tranexamic acid without FFP usage and determined the effect on 30 day mortality.

Methods

Retrospective data analysis with 372 consecutive adult liver transplant patients performed between 2007 and 2011.

Results

Thrombelastometry guided coagulation management resulted in a transfusion rate for fibrinogen concentrates in 50.2%, PCC in 18.8%, platelet concentrates in 21.2%, tranexamic acid in 4.5%, and red blood cell concentrates in 59.4%. 30 day mortality for the whole cohort was 14.2%. The univariate analyses indicated that nonsurvivors received significantly more fibrinogen concentrates, PCC, red blood cell concentrates, platelet concentrates, and infusion volume, and had a higher MELD score. However, association with mortality was weak as evidenced by receiver operating characteristic curve analyses. Further univariate analyses demonstrated, that up to 8 g of fibrinogen did not increase mortality compared to patients not receiving the coagulation factor. Multivariate analysis demonstrated that platelet concentrates (p = 0.0002, OR 1.87 per unit), infused volume (p = 0.0004, OR = 1.13 per litre), and MELD score (p = 0.024; OR 1.039) are independent predictors for mortality. Fibrinogen concentrates, PCC, and red blood cell concentrates were ruled out as independent risk factors.

Conclusions

ROTEM™ guided substitution with fibrinogen concentrates and PCC does not negatively affect mortality after liver transplantation, while the well-known deleterious effect associated with platelet concentrates was confirmed.

Perioperative hemostatic management in the cirrhotic patient: a position paper on behalf of the Liver Intensive Care Group of Europe (LICAGE)

Recent data demonstrated that amongst patients undergoing elective surgery the prevalence of cirrhosis is 0.8% equating to approximately 25 million cirrhotic patients undergoing surgery each year worldwide. Overall, the presence of cirrhosis is independently associated with 47% increased risk of postoperative complications and over two and a half-increased risk of in-hospital mortality in patients undergoing elective surgery. In particular, perioperative patients with chronic liver disease have long been assumed to have a major bleeding risk on the basis of abnormal results for standard tests of hemostasis. However, recent evidence outlined significant changes to traditional knowledge and beliefs and, nowadays, with more sophisticated laboratory tests, it has been shown that patients with chronic liver disease may be in hemostatic balance as a result of concomitant changes in both pro- and antihemostatic pathways. The aim of this paper endorsed by the Liver Intensive Care Group of Europe was to provide an up-to-date overview of coagulation management in perioperative patients with chronic liver disease focusing on patient blood management, monitoring of hemostasis, and current role of hemostatic agents.

Significant Hyperfibrinolysis in a Patient With Intracardiac Thrombosis: To Give Antifibrinolytics or Not?

The hemostatic system is a delicate balance between the coagulation, anticoagulation, and fibrinolytic systems and is responsible for preventing both hemorrhage and thrombosis. End stage liver disease is characterized by a rebalanced hemostatic system that is fragile and easily tipped towards either hemorrhage or thrombosis. During an orthotopic liver transplantation, patients are exposed to a wide variety of factors that can shift them from a hypercoagulable state to a hypocoagulable state almost instantaneously. The treatment for these two disease states contradict each other, and therefore patients in this condition can be extremely difficult to manage. Here, we present a patient who underwent an orthotopic liver transplantation and suffered an intracardiac thrombosis shortly after reperfusion of the donor graft, that resolved with supportive care, who then went on to develop severe persistent hyperfibrinolysis and massive hemorrhage that was successfully treated with an antifibrinolytic agent.

Effect of Liver Disease Etiology on ROTEM Profiles in Patients Undergoing Liver Transplantation

BACKGROUND

Coagulation abnormalities in liver transplant patients are complex and may be related to the underlying liver disease. We evaluated the effects of disease etiology on whole-blood rotational thromboelastometry (ROTEM; Pentapharm GmbH, Munich, Germany) profile and association with thrombotic complications following liver transplantation.

METHODS

Analysis of perioperative data from patients undergoing liver transplantation between January 1, 2012 and December 31, 2016. Patients were grouped based on the biology of their underlying liver disease: hepatocellular carcinoma (HCC), biliary etiology, and non-biliary etiology. The primary outcome was the EXTEM A10 value of the pre-incision ROTEM. Secondary outcomes included associations between EXTEM A10 value and incidence of postoperative thrombotic complications.

RESULTS

Three hundred fifty patients met the eligibility criteria: 60 had biliary etiologies, 203 had non-biliary etiologies, and 87 had HCC. EXTEM A10 values were significantly higher in patients with biliary etiologies than those with non-biliary etiologies (mean difference, 13.8; 95% CI: 10.1 to 17.5; P = .001) and those with HCC (mean difference, 10.4; 95% CI: 6.2 to 14.7; P = .001). Patients with non-biliary etiologies had slightly higher values than those with HCC (mean difference, -3.3; 95% CI: -6.6 to -0.1; P = .04). Higher values for biliary etiologies remained after adjusting for liver disease severity, platelet count, and fibrinogen level. There was no significant difference in EXTEM A10 values between patients who suffered thrombotic complications and those who did not (mean difference: 4.3, 95% CI: -1.3 to 9.9, P = .13).

CONCLUSION

Patients with biliary diseases demonstrated higher EXTEM A10 values compared to those with non-biliary diseases or HCC. This was not fully explained by differences in disease severity, platelet count, or fibrinogen level. Pre-incision EXTEM A10 values do not predict incidence of postoperative thrombotic complications.

Hypercoagulability in End-stage Liver Disease: Review of Epidemiology, Etiology, and Management

In this review, we analyze the epidemiology of thromboses related to end-stage liver disease (ESLD), discuss causes of hypercoagulability, describe susceptible populations, and critically evaluate proposed prophylaxis and treatment of thromboses. Classically, ESLD has been regarded as a model for coagulopathy, and patients were deemed to be at high risk for bleeding complications. Patients with ESLD are not auto-anticoagulated, and they do not have a lower risk of portal vein thrombosis, intracardiac thrombus formation, pulmonary embolism or hepatic artery thrombosis. Though the cause of hypercoagulability is multifactorial, endothelial dysfunction likely plays a central role for all patients with ESLD. Some subpopulations, such as patients with nonalcoholic steatohepatitis and autoimmune conditions, are at increased risk of thrombotic events as are patients of Hispanic ethnicity. The science behind prophylaxis of different types of clotting and treatment of thromboses is developing rapidly. A number of medications, including low molecular weight heparin, unfractionated heparin, aspirin, vitamin K antagonists, and direct oral anticoagulants can be used, but clear guidelines are lacking. Acute intraoperative clotting can be associated with high mortality. Routine use of transesophageal echocardiography can be helpful in early recognition and treatment of intraoperative thrombosis. Heparin should be reserved for cases of intracardiac thrombus/pulmonary embolism without hemodynamic instability. In unstable patients, low dose of recombinant tissue plasminogen activator can be used. In this new era of heightened awareness of thrombotic events in ESLD patients, prospective randomized trials are urgently needed to best guide clinical practice.

The early outcomes of candidates with portopulmonary hypertension after liver transplantation

Background

Portopulmonary hypertension (PPH) was once regarded as a contraindicaton to liver transplantation (LT). However, growing evidence has indicated that PPH patients undergoing LT may show similar outcomes compared to those without PPH, and researchers have recommended it not be an absolute contraindication. Given this controversy, we aimed to identify and review the current evidence on this topic and to provide a comparison of the outcomes after LT between candidates with PPH and those without.

Methods

We systematically searched the MEDLINE, EMBASE and Cochrane Library databases for all studies that compared the outcomes of PPH patients and those without PPH after LT. All studies reporting outcomes of PPH patients versus those without PPH (Control) were further considered for inclusion in this meta-analysis. Odds ratios (OR) and 95% confidence intervals (CI) were calculated to compare the pooled data between PPH and Control groups.

Results

Eleven retrospective trials and one prospective, randomized, controlled trial, involving 37,686 transplant recipients were included. The PPH patients had increased 1-year mortality with an OR of 1.59 (95% CI = 1.26–2.01, P = 0.0001) compared to the control group. There was no significant difference in graft loss and 30-day mortality after LT between the two groups.

Conclusions

Patients with PPH who underwent LT had increased 1-year mortality compared to those without PPH, while graft loss and 30-day mortality were similar. Nevertheless, LT may be a reasonable therapeutic option for some patients with PPH, but further studies are needed to identify those select patients with PPH who would benefit most from LT.

Electronic supplementary material

The online version of this article (10.1186/s12876-018-0797-8) contains supplementary material, which is available to authorized users.

Transesophageal ultrasonography during orthotopic liver transplantation: Show me more

The first perioperative transesophageal echocardiography (TEE) guidelines published 21 years ago were mainly addressed to cardiac anesthesiologists. TEE has since expanded its role outside this setting and currently represents an invaluable tool to assess chamber sizes, ventricular hypertrophy, and systolic, diastolic, and valvular function in patients undergoing orthotopic liver transplantation (OLT). Right-sided microemboli, right ventricular dysfunction, and patent foramen ovale (PFO) are the most common intra-operative findings described during OLT. However, left ventricular outflow tract obstruction and left ventricular ballooning syndrome are more difficult to recognize and less frequent. Transesophageal ultrasonography (TEU) during OLT is also underused. Its applications are as follows: (1) assistance in the difficult placement of pulmonary arterial catheters; (2) help with catheterization of great vessels for external veno-venous bypass placement; (3) intra-operative evaluation of surgical liver anastomosis patency, if feasible, through the liver window; and (4) intra-operative investigation of "acute hypoxemia" due to pulmonary and cardiac issues using trans-esophageal lung ultrasound (TELU). The aims of this review are as follows: (1) to summarize the uses of TEE and TEU throughout all phases of OLT, and (2) to describe other new feasible applications.

Successful Removal of Intracardiac Thrombus With a Poole Tip Suction Device Through the Inferior Vena Cava of a Patient With Cardiovascular Collapse During Liver Transplant: A Case Report

Intracardiac thrombus occurs in 1.2%-6.3% of patients undergoing orthotopic liver transplant and is associated with a high mortality rate. The pathophysiology and risk factors for development of this complication are not well understood. No consensus treatment guidelines exist, and specific therapies are associated with serious risks. We present the timely and successful use of a Poole tip surgical suction device advanced into the right atrium through a cavotomy created in the inferior vena cava to remove a large right atrial thrombus during liver transplant. The thrombus was identified with transesophageal echocardiography and was causing cardiovascular collapse.

Critical Importance of Low-Dose Tissue Plasminogen Activator Policy for Treating Intraoperative Pulmonary Thromboembolism During Liver Transplantation

Tissue plasminogen activator (tPA) has been reported to treat intraoperative pulmonary thromboembolism (PTE) during liver transplantation (LT). However, tPA administration is often delayed due to fear of uncontrolled bleeding and storage in a refrigerator outside of operating rooms. Various dosages of tPA were used. We hypothesize that a policy of tPA storage and low dosage use improves patient outcomes. At a transplantation center, a multidisciplinary committee has implemented a tPA policy since April 2014, which includes the following: (1) timely administering of low-dose tPA (0.5-4 mg) for intraoperative PTE; (2) keeping 2 vials of tPA (2 mg/vial) in the operating room at room temperature; and (3) transferring unused tPA vials to the cardiology catheterization laboratory for next-day use. A prospective observational study was conducted to record the incidence and outcome of PTE during LTs. Over the next 19 months, 99 adult deceased donor LTs were performed with 1 (1.0%) intraoperative PTE. A 45-year-old woman with hepatitis C developed PTE within 5 minutes after graft reperfusion. A 2-mg tPA was immediately administered via a central venous line with hemodynamic improvement and clot lysis. Thromboelastography was normalized in 90 minutes. Five LT cases developing intraoperative PTE have been reported to receive “standard” dosages of tPA (20-110 mg) or urokinase (4400 IU/kg), which were administered more than 20 minutes after the diagnosis of PTE. One intraoperative death and one later mortality were noted with intracranial hemorrhages/infarction of 3 cases. The multidisciplinary low-dose tPA policy for PTE was suggested to be effective.

A Comprehensive Review of Transesophageal Echocardiography During Orthotopic Liver Transplantation

Orthotopic liver transplantation (OLT) is characterized by significant hemodynamic disturbances and anesthetic challenges. Intraoperative transesophageal echocardiography (TEE) can be used to guide management during these procedures. This review examines the role of echocardiography during OLT, presents common TEE findings during each phase of OLT, and discusses the benefits demonstrated with TEE use and the safety of TEE in this patient population. Finally, the authors propose an algorithm for the safe use of TEE during OLT.

The Coagulation Profile of End-Stage Liver Disease and Considerations for Intraoperative Management

The coagulopathy of end-stage liver disease results from a complex derangement in both anticoagulant and procoagulant processes. With even minor insults, cirrhotic patients experience either inappropriate bleeding or clotting, or even both simultaneously. The various phases of liver transplantation along with fluid and blood product administration may contribute to additional disturbances in coagulation. Thus, anesthetic management of patients undergoing liver transplantation to improve hemostasis and avoid inappropriate thrombosis in the perioperative environment can be challenging. To add to this challenge, traditional laboratory tests of coagulation are difficult to interpret in patients with end-stage liver disease. Viscoelastic coagulation tests such as thromboelastography (Haemonetics Corporation, Braintree, MA) and rotational thromboelastometry (TEM International, Munich, Germany) have helped to reduce transfusion of allogeneic blood products, especially fresh frozen plasma, but have also lead to the increased use of fibrinogen-containing products. In general, advancements in surgical techniques and anesthetic management have led to significant reduction in blood transfusion requirements during liver transplantation. Targeted transfusion protocols and pharmacologic prevention of fibrinolysis may further aid in the management of the complex coagulopathy of end-stage liver disease.

Viscoelastic Monitoring to Guide Hemostatic Resuscitation in Liver Transplantation Surgery

Coagulopathic bleeding must be anticipated during liver transplantation (LT) surgery. Patients with end-stage liver disease (ESLD) often present with disease-related hematologic disturbances, including the loss of hepatic procoagulant and anticoagulant clotting factors and thrombocytopenia. Transplantation surgery itself presents additional hemostatic changes, including hyperfibrinolysis. Viscoelastic monitoring (VEM) is often used to provide targeted, personalized hemostatic therapies for complex bleeding states including cardiac surgery and major trauma. The use in these coagulopathic conditions led to its application to LT, although the mechanisms of coagulopathy in these patients are quite different. While VEM is often used during transplant surgeries in Europe and North America, evidence supporting its use is limited to a few small clinical studies. The theoretical and clinical applications of the standard and specialized VEM assays are discussed in the setting of LT and ESLD.

Coagulation Management During Liver Transplantation: Use of Fibrinogen Concentrate, Recombinant Activated Factor VII, Prothrombin Complex Concentrate, and Antifibrinolytics

Coagulation management, and transfusion practice in liver transplantation (LT) have been evolving in the recent years due to better understanding of coagulation abnormalities in end-stage liver disease, and clinical management of LT patients. Avoidance of allogeneic blood components is feasible in some patients, but multi-modal coagulation therapies may be necessary in others who develop complex coagulopathy due to hemorrhage, hemodilution, hypothermia, and acid-base disturbances. Transfusions of plasma and cryoprecipitate remain to be the mainstay therapy for procoagulant factor replacement during LT. Clinical efficacy and safety of these products are limited by logistic issues (eg, thawing), and mostly noninfectious complications. Considering potential alternatives to conventional transfusion is thus important to improve hemostatic resuscitation in complex LT cases. The present review is mainly focused on procoagulant properties of plasma and platelet transfusion, and currently available plasma-derived and recombinant factor concentrates, and antifibrinolytic agents in LT patients. The role of viscoelastic coagulation tests to guide specific component therapies will be also discussed.

Use of low-dose thrombolytics for treatment of intracardiac thrombus and massive pulmonary embolus after aborted liver transplant leads to recovery of right ventricular function and redo liver transplantation

This is a 61-year-old man with end-stage liver disease who experienced cardiac arrest secondary to a massive pulmonary embolus and intracardiac thrombus during cannulation for veno-venous extracorporeal membrane oxygenation (ECMO) in preparation for orthotopic liver transplantation (OLT). Surgery was aborted and the patient was taken back to the intensive care unit in cardiogenic shock on multiple vasopressors. The patient was unresponsive to heparin bolus and too high risk for systemic thrombolytics or embolectomy. He was ultimately treated with 12 mg total of alteplase through his pulmonary artery catheter over 3 hours. He had subsequent resolution of his cardiogenic shock and proceeded with successful liver transplantation 5 days after his initial event without any bleeding complications. Low-dose thrombolytic therapy in the setting of absolute contraindications to thrombolysis allowed for recovery of cardiac function and, ultimately redo OLT in a patient with otherwise little hope of survival.

Coagulopathy Before and After Liver Transplantation: From the Hepatic to the Systemic Circulatory Systems

The hemostatic environment in patients with cirrhosis is a delicate balance between prohemostatic and antihemostatic factors. There is a lack of effective laboratory measures of the hemostatic system in patients with cirrhosis. Many are predisposed to pulmonary embolus, deep vein thrombosis, and portal vein thrombosis in the pretransplantation setting. This pretransplantation hypercoagulable milieu seems to extend for at least several months post-transplantation. Patients with nonalcoholic fatty liver disease, inherited thrombophilia, portal hypertension in the absence of cirrhosis, and hepatocellular carcinoma often require individualized approach to anticoagulation. Early reports suggest a potential role for low-molecular-weight heparins and direct-acting anticoagulants.

Massive Fulminant Thrombosis During Liver Transplantation in a Patient With a Previously Unknown Antithrombin Pathway Mutation

We describe a case of fulminant intraoperative thrombosis during deceased donor liver transplantation. Despite significant medical bleeding, the patient suddenly developed diffuse thrombosis in all chambers of the heart and pulmonary vasculature resulting in intraoperative death. The patient's postmortem genetic analysis demonstrated a deleterious missense mutation in a coagulation pathway gene, SERPINC1, which codes for antithrombin III. The level of antithrombin III was not available to directly prove the causality of thrombosis, but our findings suggest that this mutation, in combination with antifibrinolytic administration in a hypercoagulable cirrhotic patient, might have contributed to the development of this catastrophic thrombotic event.

Intraoperative Diagnosis of Intracardiac Thrombus During Orthotopic Liver Transplantation With Transesophageal Echocardiography: A Case Series and Literature Review

Anesthesia for orthotopic liver transplantation (OLT) is challenging for any anesthesiologist as the patients undergoing this procedure are among the most critically ill. Adding to the underlying complexity of OLT management is the rare complication of an intracardiac thrombus (ICT). Intracardiac thrombi can present following liver allograft reperfusion resulting in high morbidity and mortality. Currently there is no consensus treatment for ICT, and the gold standard for diagnosis is intraoperative transesophageal echocardiography (TEE); these 2 factors lead to a dangerous amalgam of the difficulty in diagnosing and treating the disease. We describe 2 separate cases in detail of ICT formation during OLT that were recognized and diagnosed with intraoperative TEE. These 2 cases highlight the important role of TEE in the management of ICT. A thorough literature review that follows analyzes our current understanding of ICT during OLT and the vital function of TEE by every anesthesiologists regardless of formal TEE training. Broader use of TEE during all OLTs can help narrow the anesthesiologist’s differential diagnosis during the acute phases of transplantation and should be considered in all liver transplant surgeries.

Anesthesia Management of Liver Transplantation

Anesthesia for liver transplantation pertains to a continuum of critical care of patients with end-stage liver disease. Hence, anesthesiologists, armed with a comprehensive understanding of pathophysiology and physiologic effects of liver transplantation on recipients, are expected to maintain homeostasis of all organ function. Specifically, patients with fulminant hepatic failure develop significant changes in cerebral function, and cerebral perfusion is maintained by monitoring cerebral blood flow and cerebral metabolic rate of oxygen, and intracranial pressure. Hyperdynamic circulation is challenged by the postreperfusion syndrome, which may lead to cardiovascular collapse. The goal of circulatory support is to maintain tissue perfusion via optimal preload, contractility, and heart rate using the guidance of right-heart catheterization and transesophageal echocardiography. Portopulmonary hypertension and hepatopulmonary syndrome have high morbidity and mortality, and they should be properly evaluated preoperatively. Major bleeding is a common occurrence, and euvolemia is maintained using a rapid infusion device. Pre-existing coagulopathy is compounded by dilution, fibrinolysis, heparin effect, and excessive activation. It is treated using selective component or pharmacologic therapy based on the viscoelastic properties of whole blood. Hypocalcemia and hyperkalemia from massive transfusion, lack of hepatic function, and the postreperfusion syndrome should be aggressively treated. Close communication between all parties involved in liver transplantation is also equally valuable in achieving a successful outcome.

Prolonged Intraoperative Cardiac Resuscitation Complicated by Intracardiac Thrombus in a Patient Undergoing Orthotopic Liver Transplantation

We report the case of successful resuscitation after prolonged cardiac arrest during orthotopic liver transplantation. After reperfusion, the patient developed ventricular tachycardia, complicated by intracardiac clot formation and massive hemorrhage. Transesophageal echocardiography demonstrated stunned and nonfunctioning right and left ventricles, with developing intracardiac clots. Treatment with heparin, massive transfusion and prolonged cardiopulmonary resuscitation ensued for 51 minutes. Serial arterial blood gases demonstrated adequate oxygenation and ventilation during cardiopulmonary resuscitation. Cardiothoracic surgery was consulted for potential use of extracorporeal membrane oxygenation, however, the myocardial function improved and the surgery was completed without further intervention. On postoperative day 6, the patient was extubated without neurologic or cardiac impairment. The patient continues to do well 2 years posttransplant, able to perform independent daily activities of living and his previous job. This case underscores the potential for positive outcomes with profoundly prolonged, effective advanced cardiovascular life support in patients who experience postreperfusion syndrome.