Acute Liver Failure: Managing Coagulopathy and the Bleeding Diathesis

Precannulation International Normalized Ratio is Independently Associated With Mortality in Veno-Arterial Extracorporeal Membrane Oxygenation

OBJECTIVES

To explore whether precannulation international normalized ratio (INR) is associated with in-hospital mortality in venoarterial extracorporeal membrane oxygenation (VA-ECMO) patients.

DESIGN

A retrospective, observational cohort study.

SETTING

A quaternary care academic medical center.

PARTICIPANTS

Patients with cardiogenic shock on VA-ECMO for >24 hours.

INTERVENTIONS

None, observational study.

MEASUREMENTS AND MAIN RESULTS

A total of 188 patients who were on VA-ECMO were included over three years. Patients were stratified into three groups based on their pre-ECMO INR: INR <1.5, INR 1.5 to 1.8, and INR >1.8. For all patients, demographics, comorbidities, and ECMO details were recorded. The study's primary outcome was in-hospital mortality and secondary outcomes included major bleeding, minor bleeding, allogeneic transfusion, ischemic stroke, intracranial hemorrhage, acute renal failure, acute liver failure, gastrointestinal bleeding, intensive care unit and hospital lengths of stay. A multivariate logistic regression was used to determine whether precannulation INR was associated independently with in-hospital mortality. In-hospital mortality differed significantly by INR group (51.6% INR >1.8 v 42.3% INR 1.5-1.8 v 24.3% INR <1.5; p = 0.004). In a multivariate logistic regression model, precannulation INR >1.8 was associated independently with an increased odds of mortality (odds ratio, 2.48; 95% confidence interval, 1.05-6.04) after controlling for sex, Survival after VA- ECMO score, and ECMO indication. An INR within 1.5 to 1.8 did not confer an increased mortality risk.

CONCLUSIONS

An INR >1.8 before VA-ECMO cannulation is associated independently with in-hospital mortality. Precannulation INR should be considered by clinicians so that ECMO resources can be better allocated and risks of organ failure and intracranial hemorrhage can be better understood.

Clinical Considerations of Coagulopathy in Acute Liver Failure

Acute liver failure (ALF) is the rapid onset of severe liver dysfunction, defined by the presence of hepatic encephalopathy and impaired synthetic function (international normalized ratio of ≥1.5) in the absence of underlying liver disease. The elevated international normalized ratio value in ALF is often misinterpreted as an increased hemorrhagic tendency, which can lead to inappropriate, prophylactic transfusions of blood products. However, global assessments of coagulopathy via viscoelastic tests or thrombin generation assay suggest a reestablished hemostatic, or even hypercoagulable, status in patients with ALF. Although the current versions of global assays are not perfect, they can provide more nuanced insights into the hemostatic system in ALF than the conventional measures of coagulopathy.

Coagulation abnormalities, bleeding, thrombosis, and management of patients with acute liver failure in Australia and New Zealand

BACKGROUND AND AIM

To study the management of coagulation and hematological derangements among severe acute liver failure (ALF) patients in Australia and New Zealand liver transplant intensive care units (ICUs).

METHODS

Analysis of key baseline characteristics, etiology, coagulation and hematological tests, use of blood products, thrombotic complications, and clinical outcomes during the first ICU week.

RESULTS

We studied 62 ALF patients. The first day median peak international normalized ratio was 5.5 (inter-quartile range [IQR] 3.8-8.7), median longest activated partial thromboplastin time was 62 s (IQR 44-87), and median lowest fibrinogen was 1.1 (IQR 0.8-1.6) g/L. Fibrinogen was only measured in 85% of patients, which was less than other tests (P < 0.0001). Median initial lowest platelet count was 83 (IQR 41-122) × 10⁹ /L. Overall, 58% of patients received fresh frozen plasma, 40% cryoprecipitate, 35% platelets, and 15% prothrombin complex concentrate. Patients with bleeding complications (19%) had more severe overall hypofibrinogenemia and thrombocytopenia. Thrombotic complications were less common (10% of patients), were not associated with consistent patterns of abnormal hemostasis, and were not immediately preceded by clotting factor administration and half occurred only after liver transplantation surgery.

CONCLUSION

In ALF patients admitted to dedicated Australia and New Zealand ICUs, fibrinogen was measured less frequently than other coagulation parameters but, together with platelets, appeared more relevant to bleeding risk. Blood products and procoagulant factors were administered to most patients at variable levels of hemostatic derangement, and bleeding complications were more common than thrombotic complications. This epidemiologic information and practice variability provide baseline data for the design and powering of interventional studies.

Acute liver failure: A review for emergency physicians

INTRODUCTION

Acute liver failure (ALF) remains a high-risk clinical presentation, and many patients require emergency department (ED) management for complications and stabilization.

OBJECTIVE

This narrative review provides an evidence-based summary of the current data for the emergency medicine evaluation and management of ALF.

DISCUSSION

While ALF remains a rare clinical presentation, surveillance data suggest an overall incidence between 1 and 6 cases per million people every year, accounting for 6% of liver-related deaths and 7% of orthotopic liver transplants (OLT) in the U.S. The definition of ALF includes neurologic dysfunction, an international normalized ratio ≥ 1.5, no prior evidence of liver disease, and a disease course of ≤26 weeks, and can be further divided into hyperacute, acute, and subacute presentations. There are many underlying etiologies, including acetaminophen toxicity, drug induced liver injury, and hepatitis. Emergency physicians will be faced with several complications, including encephalopathy, coagulopathy, infectious processes, renal injury, and hemodynamic instability. Critical patients should be evaluated in the resuscitation bay, and consultation with the transplant team for appropriate patients improves patient outcomes. This review provides several guiding principles for management of acute complications. Using a pathophysiological-guided approach to the management of ALF associated complications is essential to optimizing patient care.

CONCLUSIONS

ALF remains a rare clinical presentation, but has significant morbidity and mortality. Physicians must rapidly diagnose these patients while evaluating for other diseases and complications. Early consultation with a transplantation center is imperative, as is identifying the underlying etiology and initiating symptomatic care.

Plasminogen Activator Inhibitor-1 Reduces Tissue-Type Plasminogen Activator-Dependent Fibrinolysis and Intrahepatic Hemorrhage in Experimental Acetaminophen Overdose

Acetaminophen (APAP)-induced liver injury in mice is associated with activation of the coagulation cascade and deposition of fibrin in liver. Plasminogen activator inhibitor-1 (PAI-1) is an important physiological inhibitor of tissue-type plasminogen activator (tPA) and plays a critical role in fibrinolysis. PAI-1 expression is increased in both experimental APAP-induced liver injury and patients with acute liver failure. Prior studies have shown that PAI-1 prevents intrahepatic hemorrhage and mortality after APAP challenge, but the downstream mechanisms are not clear. We tested the hypothesis that PAI-1 limits liver-related morbidity after APAP challenge by reducing tPA-dependent fibrinolysis. Compared with APAP-challenged (300 mg/kg) wild-type mice, hepatic deposition of cross-linked fibrin was reduced, with intrahepatic congestion and hemorrhage increased in PAI-1-deficient mice 24 hours after APAP overdose. Administration of recombinant wild-type human PAI-1 reduced intrahepatic hemorrhage 24 hours after APAP challenge in PAI-1-/- mice, whereas a mutant PAI-1 lacking antiprotease function had no effect. Of interest, tPA deficiency alone did not affect APAP-induced liver damage. In contrast, fibrinolysis, intrahepatic congestion and hemorrhage, and mortality driven by PAI-1 deficiency were reduced in APAP-treated tPA-/-/PAI-1-/- double-knockout mice. The results identify PAI-1 as a critical regulator of intrahepatic fibrinolysis in experimental liver injury. Moreover, the results suggest that the balance between PAI-1 and tPA activity is an important determinant of liver pathology after APAP overdose.

Bleeding Risk and Management in Interventional Procedures in Chronic Liver Disease

The coagulopathy of liver disease is distinctly different from therapeutic anticoagulation in a patient. Despite stable elevated standard clot-based coagulation assays, nearly all patients with stable chronic liver disease (CLD) have normal or increased clotting. Common unfamiliarity with the limitations of these assays in CLD may lead to inappropriate and sometimes harmful interventions, including blood product transfusions before a procedure. Knowledge of the distinct hemostatic alterations in CLD can allow identification of the small subset of patients with clinically significant coagulopathy who can benefit from hematologic optimization before invasive procedures.

Impact of alcohol consumption on the outcome of ischemic stroke and thrombolysis: role of the hepatic clearance of tissue-type plasminogen activator

BACKGROUND AND PURPOSE

Tissue-type plasminogen activator (tPA) is the only acute treatment for ischemic stroke. Unfortunately, the benefit of tPA-driven thrombolysis is not systematic, and understanding the reasons for this is mandatory. The balance between beneficial and detrimental effects of tPA might explain the limited overall efficiency of thrombolysis. Here, we investigated whether this balance could be influenced by excessive alcohol intake.

METHODS

We used a murine model of thromboembolic stroke, coupled to an array of biochemical assays, near-infrared or magnetic resonance imaging scans, 2-photon microscopy, hydrodynamic transfections, and immunohistological techniques.

RESULTS

We found that 6 weeks of alcohol consumption (10% in drinking water) worsens ischemic lesions and cancels the beneficial effects of tPA-induced thrombolysis. We accumulate in vivo and in vitro evidence showing that this aggravation is correlated with a decrease in lipoprotein receptor-related protein 1-mediated hepatic clearance of tPA in alcohol-exposed mice.

CONCLUSIONS

An efficient liver-driven clearance of tPA might influence the safety of thrombolysis after stroke.

Delicate balance of bleeding and thrombosis in end-stage liver disease and liver transplantation

Liver transplantation in cirrhotic patients is accompanied by severe bleeding. Indeed, the first 100 recipients of liver allografts transplanted by Thomas E. Starzl died mainly by uncontrolled bleeding. Since then, much progress has been made as to the understanding of the pathophysiology and the treatment of hemostatic disorders in cirrhotic patients. The aim of this review is to provide a state-of-the-art overview on recent developments and treatment options for hemostatic disorder in cirrhotic patients. Patients with end-stage-liver disease (ESLD) do not suffer only from procoagulant deficiency; there is also a lack of natural anticoagulants (i.e. proteins C and S) and profibrinolytics. Conventional laboratory methods such as the determination of the international normalized ratio or the activated partial thromboplastin time cannot predict bleeding complications in these patients. Progressive diagnostic techniques reveal that cirrhotic patients have the same capacity to produce thrombin like healthy volunteers. Moreover, cirrhotic patients--and particularly those with primary biliary cirrhosis or primary sclerosing cholangitis-- are at a higher risk for developing thrombosis as compared with healthy controls. Hemostatic alterations are common in cirrhotic patients; they involve both the pro- and the anticoagulant pathways. However, this is a very delicate balance, which may be shifted to either of these pathways by different treatments thereby causing bleeding or thrombosis, respectively.

Glasgow coma scale and APACHE-II scores affect the liver transplantation outcomes in patients with acute liver failure

BACKGROUND

The timing and selection of patients for liver transplantation in acute liver failure are great challenges. This study aimed to investigate the effect of Glasgow coma scale (GCS) and APACHE-II scores on liver transplantation outcomes in patients with acute liver failure.

METHOD

A total of 25 patients with acute liver failure were retrospectively analyzed according to age, etiology, time to transplantation, coma scores, complications and mortality.

RESULTS

Eighteen patients received transplants from live donors and 7 had cadaveric whole liver transplants. The mean duration of follow-up after liver transplantation was 39.86+/-40.23 months. Seven patients died within the perioperative period and the 1-, 3-, 5-year survival rates of the patients were 72%, 72% and 60%, respectively. The parameters evaluated for the perioperative deaths versus alive were as follows: the mean age of the patients was 33.71 vs 28 years, MELD score was 40 vs 32.66, GCS was 5.57 vs 10.16, APACHE-II score was 23 vs 18.11, serum sodium level was 138.57 vs 138.44 mmol/L, mean waiting time before the operation was 12 vs 5.16 days. Low GCS, high APACHE-II score and longer waiting time before the operation (P<0.01) were found as statistically significant factors for perioperative mortality.

CONCLUSION

Lower GCS and higher APACHE-II scores are related to poor outcomes in patients with acute liver failure after liver transplantation.

Intraoperative predictors of short-term mortality in living donor liver transplantation due to acute liver failure

BACKGROUND

Acute liver failure (ALF) is a rare and fatal disease with rapidly deteriorating clinical features. Many predictive models for ALF outcomes have been tested, but none have been adopted as definitive guidelines for prognosis because of inconsistencies in accuracy. Most prognostic models for ALF are based on preoperative patient conditions, thus ignoring various specific intraoperative features relevant to postoperative outcomes. We investigated whether intraoperative factors predicted short-term mortality due to ALF in living donor liver transplantations (LDLT).

METHODS

We retrospectively collected intraoperative data, including surgical time, fluctuations in mean blood pressure (MBP) and heart rate, mean pulmonary arterial pressure (PAP), central venous pressure (CVP), urine output, laboratory data, oxygen indices (PaO(2)/FiO(2)), administered drugs, and transfusion of packed red blood cells (PRBCs) from 101 patients with ALF who underwent LDLT. After simple relationships of individual intraoperative variables with 1-month posttransplant mortality were analyzed, we examined potentially significant intraoperative variables (P < .10) by a multivariate adjustment process with preoperative indicators of ALF prognosis.

RESULTS

Intraoperative MBP fluctuations, first mean PAP and CVP, last oxygen index, administered calcium chloride, and PRBC transfusion showed individual associations with posttransplant mortality of ALF patients (P < .05). After multivariate adjustment, PRBC transfusion of ≥ 10 pints (odds ratio 4.73; 95% confidence interval [CI] 1.06-21.16) and MBP fluctuations (odds ratio 1.26; 95% CI 1.00-1.58) were identified to be independent predictors of 1-month posttransplant mortality, together with preoperative factors, including severe hepatic encephalopathy, and a Model for End-stage Liver Disease score ≥ 30 points (area under the curve 0.82, P < .001).

CONCLUSION

MBP fluctuations and large blood transfusions were intraoperative predictors of short-term mortality after LDLT due to ALF. Increased attention to intraoperative manifestations should provide valuable prognostic information for ALF.

Hemostasis in patients with acute kidney injury secondary to acute liver failure

Acute kidney injury (AKI) occurs in over half of patients with acute liver failure. Despite prolonged prothrombin times and thrombocytopenia, continuous renal replacement therapy circuits frequently develop clots during patient treatment. Here we assessed factors contributing to this by measuring coagulation parameters (standard coagulation tests, pro- and anticoagulant factors, thromboelastography, and thrombin generation) in 20 consecutive patients with acute liver failure; mean age 42 years. Within 48 h, 10 had developed stage 3 AKI and 9 required continuous renal replacement therapy, of whom 2 had frequent circuit clots. The patients with stage 3 AKI were found to have significantly lower platelet counts and levels of factor V and the natural anticoagulants antithrombin, Protein C and Protein S, but increased extrinsic pathway activation and von Willebrand factor levels. Tissue factor levels were greater in those with stage 3 AKI, as was microparticle activity. Although patients with acute liver failure and advanced AKI requiring continuous renal replacement therapy have an even more marked thrombocytopenia and more prolonged extrinsic pathway activation, this was not associated with increased bleeding. Thus, more frequent circuit clots during continuous renal replacement therapy appear to be due to a combination of increased tissue factor and microparticle release, endothelial activation, and reduction in natural anticoagulants.

The effects of N-acetylcysteine on hepatic function during isoflurane anaesthesia for laparoscopic surgery patients

Introduction:

Although most general anaesthesia procedures are performed without any complications, volatile agents may have adverse effects on various living systems. This study aims to compare the antioxidant effects of isoflurane and N-acetylcysteine (NAC) on liver function.

Methods:

Forty-one patients in the ASA I-II risk groups, who were scheduled to undergo gynaecologic laparoscopy, were randomly divided into two groups: The placebo (group P, n=21) and the NAC group (group N, n=20). In both groups, anaesthesia was maintained with 1–2% isoflurane in 50% Oxygen–50% N₂O at 6 l/min, also administered by inhalation. Venous blood samples were obtained before anaesthesia induction, and then in the postoperative 1^st hour and at the 24^th hour. The samples were centrifuged and serum levels of glutathione S-transferase (GST), malondialdehyde (MDA), aspartate amino transferase (AST), alanine amino transferase (ALT), lactate dehydrogenase (LDH), gamma glutamyltranspeptidase (GGT), prothrombin time (PT), activated partial thromboplastin time (aPTT) and international normalised ratio were determined.

Results:

GST levels were significantly higher in group N than in group P in the postoperative 1^st hour. Postoperative values of GST in the two groups were higher when compared to preoperative values (P<0.05). When postoperative levels were compared with preoperative levels, the postoperative MDA levels of group N were significantly higher (P<0.05). Levels of AST, ALT, GGT and LDH in both groups revealed significant decreases at the postoperative 1^st hour and postoperative 24^th hour compared to preoperative values (P<0.05, P<0.001). PT values were significantly higher in both groups in the postoperative 1^st hour and 24^th hour (P<0.05, P<0.001), although there were no differences in aPTT levels.

Conclusion:

Our results showed that liver functions were well preserved with administration of NAC during anaesthesia with isoflurane. Isoflurane with NAC has lesser effect on liver function tests compared to isoflurane alone.

Coagulation in hepatobiliary disease

OBJECTIVE

To review the pathogenesis and clinical consequences of coagulation abnormalities accompanying hepatobiliary disorders and to highlight the need for further studies to characterize these derangements and their treatment options in small animal patients.

DATA SOURCES

Veterinary and human medical literature: original research articles, scientific reviews, consensus statements, and recent texts.

SUMMARY

The liver plays an important role in the production and clearance of many components of coagulation. A wide range of hemostatic derangements can occur in patients with hepatobiliary disease including alterations in platelet number and function, coagulation factor levels, anticoagulants, vascular endothelial function, and fibrinolysis. As these hemostatic alterations include both pro- and anticoagulation pathways, the net result is often a rebalanced hemostatic system that can be easily disrupted by concurrent conditions resulting in either clinical bleeding or thrombosis. Conventional coagulation tests are inadequate at identifying the spectrum of coagulation alterations occurring in patients with hepatobiliary disease, but their evaluation is necessary to assess bleeding risk and provide prognostic information. A paucity of information exists regarding the treatment of the coagulation derangements in small animals with hepatobiliary disease. Extrapolation from human studies provides some information about potential treatment options, but further studies are warranted in this area to elucidate the best management for coagulation abnormalities in dogs and cats with hepatobiliary disease.

CONCLUSION

Hepatobiliary disease can have profound effects on coagulation function leading to hypercoagulable or hypocoagulable states. Overall coagulation status with hepatobiliary disease depends on both the type and severity of disease and the presence of associated complications.

A new enteral diet, MHN-02, which contains abundant antioxidants and whey peptide, protects against carbon tetrachloride-induced hepatitis

BACKGROUND

Inflammatory or oxidative stress is related to various diseases, including not only inflammatory diseases, but also diabetes, cancer, and atherosclerosis. The aim of this study was to evaluate the anti-inflammatory effects of a new enteral diet, MHN-02, which contains abundant antioxidants and whey peptide. The study also investigated the ability of MHN-02 to attenuate lethality, liver injury, the production of inflammatory cytokines, and the production of oxidized products using a carbon tetrachloride-induced rat model of severe fulminant hepatitis.

METHODS

Male Sprague-Dawley rats were fed either a control diet or the MHN-02 diet for 14 days and injected with 2 mL/kg of carbon tetrachloride. Survival of rats was monitored from day 0 to day 3. To evaluate liver injury, inflammation, and oxidative stress, blood and liver samples were collected, and aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, interleukin 6, tumor necrosis factor-α, and superoxide dismutase activity as a free radical scavenger were measured. A portion of the liver was evaluated histologically.

RESULTS

The survival rates of rats receiving the MHN-02 diet and the control diet were 90% and 55%, respectively. In the MHN-02 diet group, levels of serum liver enzymes and serum cytokines were significantly lower than in the control group. Superoxide dismutase activity in the MHN-02 diet was significantly higher in the MHN-02 group. Pathological lesions were significantly larger in the control group.

CONCLUSION

Supplementation of enteral diets containing whey peptide and antioxidants may protect against severe hepatitis.