Efficacy and safety of repeated perioperative doses of recombinant factor VIIa in liver transplantation

How to manage hemostasis in patients with liver disease during interventions

Patients with advanced chronic liver disease (CLD) often need procedures to both treat and prevent complications of portal hypertension such as ascites or gastrointestinal bleeding. Abnormal results for hemostatic tests, such as prolonged prothrombin time, international normalized ratio, and/or thrombocytopenia, are commonly encountered, raising concerns about increased bleeding risk and leading to transfusion to attempt to correct prior to interventions. However hemostatic markers are poor predictors of bleeding risk in CLD, and routine correction, particularly with fresh frozen plasma and routine platelet transfusions, should be avoided. This narrative review discusses the hemostatic management of patients with CLD using 2 case descriptions.

Patient Blood Management in Liver Transplant—A Concise Review

Transfusion of blood products in orthotopic liver transplantation (OLT) significantly increases post-transplant morbidity and mortality and is associated with reduced graft survival. Based on these results, an active effort to prevent and minimize blood transfusion is required. Patient blood management is a revolutionary approach defined as a patient-centered, systematic, evidence-based approach to improve patient outcomes by managing and preserving a patient’s own blood while promoting patient safety and empowerment. This approach is based on three pillars of treatment: (1) detecting and correcting anemia and thrombocytopenia, (2) minimizing iatrogenic blood loss, detecting, and correcting coagulopathy, and (3) harnessing and increasing anemia tolerance. This review emphasizes the importance of the three-pillar nine-field matrix of patient blood management to improve patient outcomes in liver transplant recipients.

Rational hemostatic management in cirrhosis: from old paradigms to new clinical challenges

INTRODUCTION

Patients with cirrhosis are at risk of both thrombotic and hemorrhagic events. Traditional hemostatic tests are inadequate to assess the complex and fragile balance of hemostasis in this setting, especially in advanced stages of disease such as decompensated cirrhosis or acute on chronic liver failure (ACLF). Furthermore, the indiscriminate use of pro-hemostatic agents for prophylaxis and treatment of bleeding episodes is still debated and often contraindicated. Alongside, splanchnic, and peripheral thrombotic events are frequent in this population and require management that involves a careful balance between risks and benefits of antithrombotic therapy.

AREAS COVERED

This review aims to address the state of the art on the clinical management of the hemostatic balance of cirrhosis in terms of established knowledge and future challenges.

EXPERT OPINION

The old paradigm of cirrhosis as a naturally anticoagulated condition has been challenged by more sophisticated global tests of hemostasis. Integrating this information in the clinical decision-making is still challenging for physicians and experts in hemostasis.

The Role of Vitamin K in Cirrhosis: Do Pharmaco-K-Netics Matter?

Patients with advanced liver disease who are not taking vitamin K antagonists often have an elevated international normalized ratio, potentially due to vitamin K deficiency and the decreased synthesis of clotting factors by the liver. It is possible that vitamin K deficiency is due to dietary deficiency, impaired absorption in the small intestine, or both. This has led to the practice of the administration of phytonadione to limit the risks of bleeding in these patients. However, phytonadione is available in different formulations with varying pharmacokinetics and there is a paucity of data in the literature to guide optimal management. The routine use of phytonadione to correct INR in cirrhotic patients not taking warfarin should be avoided due to the lack of proven benefits. However, intravenous phytonadione may be considered in actively bleeding or critically ill patients with vitamin K deficiency. Oral formulation is unlikely to be absorbed in cirrhotic patients and should be avoided.

Periprocedural management of abnormal coagulation parameters and thrombocytopenia in patients with cirrhosis: Guidance from the SSC of the ISTH

Prolonged prothrombin time and thrombocytopenia are common in patients with cirrhosis. These parameters do not reflect the overall hemostatic rebalance or bleeding risk in the periprocedural setting; however, attempts to correct these parameters remain frequent. We review the literature on periprocedural bleeding risk, bleeding risk factors, and the risk and benefits of hemostatic interventions in patients with cirrhosis. We provide guidance recommendations on evaluating bleeding risk in this patient group and management of hemostatic abnormalities in the periprocedural setting.

In vitro characterization of CT-001-a short-acting factor VIIa with enhanced prohemostatic activity

BACKGROUND

Traumatic injury and the associated acute bleeding are leading causes of death in people aged 1 to 44 years. Acute bleeding in pathological and surgical settings also represents a significant burden to the society. Yet there are no approved hemostatic drugs currently available. While clinically proven as an effective pro-coagulant, activated factor VII (FVIIa) use in acute bleeding has been hampered by unwanted thromboembolic events. Enhancing the ability of FVIIa to quickly stop a bleed and clear rapidly from circulation may yield an ideal molecule suitable for use in patients with acute bleeding.

OBJECTIVES

To address this need and the current liability of FVIIa, we produced a novel FVIIa molecule (CT-001) with enhanced potency and shortened plasma residence time by cell line engineering and FVIIa protein engineering for superior efficacy for acute bleeding and safety.

METHODS

To address safety, CT-001, a FVIIa protein with 4 desialylated N-glycans was generated to promote active recognition and clearance via the asialoglycoprotein receptor. To enhance potency, the gamma-carboxylated domain was modified with P10Q and K32E, which enhanced membrane binding.

RESULTS

Together, these changes significantly enhanced potency and clearance while retaining the ability to interact with the key hemostatic checkpoint proteins antithrombin and tissue factor pathway inhibitor.

CONCLUSIONS

These results demonstrate that a FVIIa molecule engineered to combine supra-physiological activity and shorter duration of action has the potential to overcome the current limitations of recombinant FVIIa to be a safe and effective approach to the treatment of acute bleeding.

Use of recombinant activated factor VII for the treatment of perioperative bleeding in noncardiac surgery patients without hemophilia: A systematic review and meta-analysis of randomized controlled trials

PURPOSE

To evaluate the efficacy and safety of perioperative use of recombinant activated factor VII (rFVIIa) in noncardiac patients.

MATERIALS AND METHODS

We searched electronic databases for randomized controlled trials (RCTs) that involved the use of rFVIIa through December 13, 2019 in noncardiac patients without hemophilia. Two investigators extracted the related data and assessed the quality of the included trials.

RESULTS

Eleven RCTs examining 993 perioperative patients were ultimately included. The use of rFVIIa did not decrease all-cause mortality (RR:0.90; 95% CI:0.50,1.64; I² = 0.0%; P = 0.738), shorten the length of ICU (SMD:-0.15; 95% CI:-0.47,0.17; I² = 0.0%; P = 0.346) or hospital (SMD:0.42; 95% CI:-0.05,0.89; I² = 0.0%; P = 0.078) stay, or increase incidence of the thromboembolic events (RR:1.30; 95% CI:0.70,2.41; I² = 0.0%; P = 0.403) among perioperative patients. However, individual RCT analyses showed that the use of rFVIIa could reduce the volume of blood loss (including prostatic cancer, severe acute pancreatitis (SAP), and spinal disease) and the transfusion of RBCs (including prostatic cancer, SAP, and spinal disease) and FFP (SAP) in a subset of perioperative patients. Publication bias was not present.

CONCLUSIONS

For perioperative hemorrhagic patients, rFVIIa-based hemostatic therapy showed no effect on mortality, ICU or hospital LOS, or the rate of thromboembolic events, although it appears to decrease blood loss and reduce the need for blood product transfusion in a subset of patients.

Management of Hepatic Coagulopathy in Bleeding and Nonbleeding Patients: An Evidence-Based Review

Patients with varying degrees of hepatic dysfunction often present with presumed bleeding diathesis based on interpretation of routine measures of coagulation (prothrombin time [PT], international normalized ratio [INR], and activated partial thromboplastin time). However, standard markers of coagulation do not reflect the actual bleeding risk in this population and may lead to inappropriate administration of hemostatic agents and blood products. The concept of "rebalanced hemostasis" explains both the risk of bleeding and clotting seen in patients with liver dysfunction. The role of pharmacologic agents and blood products for prevention of bleeding during high-risk procedures and treatment of clinically significant bleeding remains unclear. Viscoelastic measurements of the clotting cascade provide information about platelets, fibrinogen/fibrin polymerization, coagulation factors, and fibrinolysis that might better represent hemostasis in vivo and may better inform management strategies. Due to the paucity of available data, firm recommendations for the use of blood products and pharmacologic agents in patients with hepatic coagulopathies are lacking, and thus, these products should not be routinely administered. Traditional laboratory tests such as PT/INR should not be the sole determinant of potential interventions. Rather, clinicians should assess factors such as the severity of bleed or bleeding risk of the procedure, the patient's risk of thromboembolism, and the strength of available evidence for specific agents and blood products to guide decision-making.

The role of evidence-based algorithms for rotational thromboelastometry-guided bleeding management

Rotational thromboelastometry (ROTEM) is a point-of-care viscoelastic method and enables to assess viscoelastic profiles of whole blood in various clinical settings. ROTEM-guided bleeding management has become an essential part of patient blood management (PBM) which is an important concept in improving patient safety. Here, ROTEM testing and hemostatic interventions should be linked by evidence-based, setting-specific algorithms adapted to the specific patient population of the hospitals and the local availability of hemostatic interventions. Accordingly, ROTEM-guided algorithms implement the concept of personalized or precision medicine in perioperative bleeding management (‘theranostic’ approach). ROTEM-guided PBM has been shown to be effective in reducing bleeding, transfusion requirements, complication rates, and health care costs. Accordingly, several randomized-controlled trials, meta-analyses, and health technology assessments provided evidence that using ROTEM-guided algorithms in bleeding patients resulted in improved patient’s safety and outcomes including perioperative morbidity and mortality. However, the implementation of ROTEM in the PBM concept requires adequate technical and interpretation training, education and logistics, as well as interdisciplinary communication and collaboration.

Impact of MELD Score-Based Organ Allocation on Mortality, Bleeding, and Transfusion in Liver Transplantation: A Before-and-After Observational Cohort Study

OBJECTIVE

The goal of this study was to evaluate the effect of the Model for End-Stage Liver Disease (MELD)-based allocation system on mortality, bleeding, and transfusion requirement in orthotopic liver transplantation (OLT).

DESIGN

OLTs were studied for this observational study (before-and-after observational cohort study).

SETTING

One community hospital.

PARTICIPANTS

The study comprised 686 patients who underwent 750 consecutive OLTs.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Patients who underwent OLT in the MELD era had an adjusted lower 1-year mortality (adjusted odds ratio 0.45 [0.24-0.83]) compared with patients who underwent OLT the pre-MELD era. No significant difference in 1-month mortality was observed. Other variables with a significant effect on 1-year mortality in multivariate analysis were preoperative international normalized ratio, intraoperative use of a phlebotomy, total intraoperative volume of crystalloid infused, and retransplantation. Blood loss was greater in the MELD era (median difference 200 mL; p < 0.001), as were red blood cell, fresh frozen plasma, and cryoprecipitate transfusions. More patients in the MELD era received at least 1 transfusion (27% v 20%; p = 0.024).

CONCLUSION

The MELD allocation system did not affect 1-month mortality, but a decrease in 1-year mortality was demonstrated. Blood loss and transfusions increased during OLTs performed in the MELD era. The role of other variables should be explored further to explain postoperative morbidity and mortality.

Utility of prothrombin complex concentrate as first-line treatment modality of coagulopathy in patients undergoing liver transplantation: A propensity score-matched study

BACKGROUND

Transfusion management during liver transplantation (LT) is aimed at reducing blood loss and allogeneic transfusion requirements. Although prothrombin complex concentrate (PCC) has been used satisfactorily in various bleeding disorders, studies on its safety, and efficacy during LT are limited.

METHODS

A retrospective chart review of adult patients who underwent living donor LT at a single institute between October 2016 and January 2018 was carried out. The safety and efficacy of PCC in reducing transfusion requirements intraoperatively in patients who received PCC were compared with patients who did not receive PCC. A propensity score-matching technique was used, at a 1:1 ratio, to remove selection bias.

RESULTS

After completing the 1:1 propensity score-matched analysis, 60 pairs of patients were identified. The use of PCC was associated with significantly decreased red blood cell transfusion requirements (6.2 ± 4.1 vs 8.23 ± 5.18, P < 0.001) and fresh frozen plasma transfusion requirements (2.6 ± 2 vs 6.18 ± 4.1, P < 0.001). The number of patients developing postoperative hemorrhagic complications was higher in the non-PCC group.

CONCLUSIONS

During LT, the use of PCC led to decreased transfusion requirements. No thromboembolic complications related to PCC were noted in this series.

In vitro efficacy of pro- and anticoagulant strategies in compensated and acutely ill patients with cirrhosis

BACKGROUND & AIMS

A simultaneous decline in pro- and anticoagulant drivers in patients with liver diseases results in a "rebalanced" haemostatic system, even in acutely ill patients. Nevertheless, both bleeding and thrombotic events are common. Here, we explored efficacy of pro- and antihaemostatic strategies in compensated and acutely ill cirrhotics which may be unpredictable given the profound haemostatic changes.

METHODS

We tested the effects in vitro of the addition of clinically relevant doses of commonly used pro- and antihaemostatic strategies in plasma from healthy individuals (n = 30) and patients with compensated (n = 18) and acutely decompensated cirrhosis (n = 18), and acute-on-chronic liver failure (n = 10). We used thrombin generation tests and fibrin clot permeability assays to assess potency of various approaches.

RESULTS

Fresh frozen plasma and recombinant factor VIIa modestly increased thrombin generation (10%-20%). Prothrombin complex concentrate increased thrombin generation two-fold in controls and 2-4-fold in patients. Clot permeability decreased after addition of fibrinogen concentrate by 51% in controls and by 50%-60% in patients. Low molecular weight heparin decreased thrombin generation by 18% in controls and by 23%-54% in patients. Similarly, dabigatran decreased thrombin generation by 33% in controls and by 47%-100% in patients. In contrast, rivaroxaban decreased thrombin generation by 55% in controls, but only by 11%-38% in patients.

CONCLUSIONS

These in vitro data suggest little prohaemostatic effect of fresh frozen plasma and recombinant factor VIIa in acutely ill cirrhotics, whereas prothrombin complex concentrate and fibrinogen concentrate clearly improved haemostasis. Furthermore, our data suggest the requirement for dose adjustments of commonly used anticoagulants in these patients.

Perioperative management of the bleeding patient

Perioperative bleeding remains a major complication during and after surgery, resulting in increased morbidity and mortality. The principal causes of non-vascular sources of haemostatic perioperative bleeding are a preexisting undetected bleeding disorder, the nature of the operation itself, or acquired coagulation abnormalities secondary to haemorrhage, haemodilution, or haemostatic factor consumption. In the bleeding patient, standard therapeutic approaches include allogeneic blood product administration, concomitant pharmacologic agents, and increasing application of purified and recombinant haemostatic factors. Multiple haemostatic changes occur perioperatively after trauma and complex surgical procedures including cardiac surgery and liver transplantation. Novel strategies for both prophylaxis and therapy of perioperative bleeding include tranexamic acid, desmopressin, fibrinogen and prothrombin complex concentrates. Point-of-care patient testing using thromboelastography, rotational thromboelastometry, and platelet function assays has allowed for more detailed assessment of specific targeted therapy for haemostasis. Strategic multimodal management is needed to improve management, reduce allogeneic blood product administration, and minimize associated risks related to transfusion.

Treatment of individuals who cannot receive blood products for religious or other reasons

By virtue of their religious principles, Jehovah's Witnesses (JWs) generally object to receiving blood products, raising numerous ethical, legal, and medical challenges for providers who care for these patients, especially in the emergent setting. In this review, we discuss several areas relevant to the care of JWs, including the current literature on "bloodless" medical care in the setting of perioperative and intraoperative management, acute blood loss, trauma, pregnancy, and malignancy. We have found that medical and administrative efforts in the form of bloodless medicine and surgery programs can be instrumental in helping to reduce risks of morbidity and mortality in these patients. Planning prior to an anticipated event associated with blood loss or anemia (such as elective surgery, pregnancy, and chemotherapy) is critical. Specifically, bloodless medicine programs should prioritize vigilant early screening and management of anemias, early establishment of patient wishes regarding transfusion, and the incorporation of those wishes into multidisciplinary medical and surgical care. Although there are now a variety of human-based and nonhuman-based products available as transfusion alternatives, the degree and quality of evidence to support their use varies significantly between products and is also largely dependent on the clinical setting.

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.

Changing Concepts of Cirrhotic Coagulopathy

The state of clinical art of the coagulopathy of cirrhosis changed considerably over the last decade. Until 2005, cirrhosis was considered as the epitome of the hemorrhagic coagulopathies and the abnormal hemostasis tests associated with the disease were corrected with infusion of fresh frozen plasma or platelets to minimize the risk of bleeding. Since that time, a great deal of work has been done and there is now a change of paradigm. The prothrombin time once considered as an isolated measure of bleeding risk was rejected, and cirrhosis shifted from a purely hemorrhagic construct to a mixed and thrombosis-prone paradigm. In this article we examine the interesting history of how these conceptual changes came about.

Use of Recombinant Activated Factor VII (Novoseven) in Trauma and Surgery: Analysis of Outcomes Reported to an International Registry

The objective was to evaluate the efficacy and safety of recombinant activated factor VII in patients with massive bleeding. Forty-five patients with severe massive hemorrhage requiring= 14 transfusion units of packed red blood cells received recombinant activated factor VII. Postdrug blood loss and transfusion requirements were assessed, and mortality was compared with predicted outcomes. Blood loss was markedly reduced in 40 of 43 (93.0%) patients, and transfusion requirements decreased after recombinant activated factor VII administration. Mortality rate in trauma patients who had massive hemorrhage was significantly reduced compared with predictions using scoring systems. This may be associated with the use of recombinant activated factor VII. This study failed to demonstrate an improvement in surgical patients. The absence of concurrent controls prevents definitive conclusions regarding actual safety or efficacy of recombinant activated factor VII.

Hemostatic balance in patients with liver cirrhosis: Report of a consensus conference

Patients with cirrhosis present with hemostatic alterations secondary to reduced availability of pro-coagulant and anti-coagulant factors. The net effect of these changes is a rebalanced hemostatic system. The Italian Association of the Study of the Liver (AISF) and the Italian Society of Internal Medicine (SIMI) promoted a consensus conference on the hemostatic balance in patients with cirrhosis. The consensus process started with the review of the literature by a scientific board of experts and ended with a formal consensus meeting in Rome in December 2014. The statements were graded according to quality of evidence and strength of recommendations, and approved by an independent jury. The statements presented here highlight strengths and weaknesses of current laboratory tests to assess bleeding and thrombotic risk in cirrhotic patients, the pathophysiology of hemostatic perturbations in this condition, and outline the optimal management of bleeding and thrombosis in patients with liver cirrhosis.

Hemostasis abnormalities in cirrhosis

PURPOSE OF REVIEW

The long-lasting paradigm of cirrhosis as the epitome of the acquired hemorrhagic coagulopathies has been challenged by evidence from the literature. This article reviews the mechanisms responsible for regulation of hemostasis in the light of the evidence provided within the last few years.

RECENT FINDINGS

Numerous studies have evaluated the mechanisms responsible for regulation of primary hemostasis, coagulation and fibrinolysis which were thought to be severely impaired in cirrhosis and were considered responsible for the abnormalities of the prothrombin time and the bleeding events observed in these patients. These evaluations have been performed by newer laboratory tests under experimental conditions that mimic closely the condition operating in vivo.

SUMMARY

Cirrhosis presents with thrombocytopenia and decreased levels of both pro- and anticoagulants. Notable exceptions are factor VIII and von Willebrand factor (VWF) which are increased. Thrombocytopenia (unless very severe) is no longer considered a bleeding risk as platelets from cirrhosis display normal adhesiveness in a flowing system that is mainly supported by the increased levels of VWF. Patients with cirrhosis generate normal amounts of thrombin that is mainly supported by the concomitant deficiency of pro- and anticoagulants that restores the balance between these two opposing drivers.

[Therapy with blood products]

Blood products are frequently used in intensive care medicine although there is little evidence of improvement in clinical outcome. The threshold for erythrocyte transfusion in non-bleeding critically ill patients is currently a hemoglobin level of 7.0 g/dl. The indications for platelet transfusion must be assessed after evaluation of the cause of thrombocytopenia, the clinical condition and the expected effect. The use of plasma should also be critically viewed, mainly due to hypervolemia. Prothrombin complex concentrates are better than plasma for warfarin reversal. There is good evidence for the use of albumin for massive paracentesis, in the treatment of hepatorenal syndrome type 1 and spontaneous bacterial peritonitis. Albumin infusion can have favorable effects in severe sepsis and septic shock. A restrictive strategy should be favored in the use of blood products and the decision should be based on a critical appraisal of the available evidence.

Reducing transfusion requirements in liver transplantation

Liver transplantation (LT) was historically associated with massive blood loss and transfusion. Over the past two decades transfusion requirements have reduced dramatically and increasingly transfusion-free transplantation is a reality. Both bleeding and transfusion are associated with adverse outcomes in LT. Minimising bleeding and reducing unnecessary transfusions are therefore key goals in the perioperative period. As the understanding of the causes of bleeding has evolved so too have techniques to minimize or reduce the impact of blood loss. Surgical “piggyback” techniques, anaesthetic low central venous pressure and haemodilution strategies and the use of autologous cell salvage, point of care monitoring and targeted correction of coagulopathy, particularly through use of factor concentrates, have all contributed to declining reliance on allogenic blood products. Pre-emptive management of preoperative anaemia and adoption of more restrictive transfusion thresholds is increasingly common as patient blood management (PBM) gains momentum. Despite progress, increasing use of marginal grafts and transplantation of sicker recipients will continue to present new challenges in bleeding and transfusion management. Variation in practice across different centres and within the literature demonstrates the current lack of clear transfusion guidance. In this article we summarise the causes and predictors of bleeding and present the evidence for a variety of PBM strategies in LT.

The Advantages and Disadvantages of Methods Used to Control Liver Bleeding: A Review

Context:

Despite advancements in the science of surgery, minimizing bleeding from parenchymal tissue of the liver continues to be one of the challenges surgeons are facing to protect patients’ lives. However, the number of surgeries needing incisions in the liver tissue, e.g. metastatectomy, is constantly increasing.

Evidence Acquisition:

A MEDLINE and conventional search of the past 50 years of the medical literature was performed to identify relevant articles on hemostasis in the liver parenchymal tissue.

Results:

The studies that have been published on hemostasis in the liver parenchymal tissue can be classified into 3 categories: 1. surgical procedures; 2. methods affecting body hemodynamic; 3. pharmacological methods. The purpose of these studies are to identify the best therapeutic approaches that not only minimize the bleeding, but also save the maximum amount of the liver tissue and minimize the use of partial liver resections.

Conclusions:

The excessive blood loss and the long time needed to control the bleeding during liver surgery impose several side effects and complications on patients. Topical hemostatic agents such as ferric chloride, potassium aluminum sulfate (alum) and aluminum chloride are safely applicable in patients. These agents might be used along with other current methods to minimize the blood loss and the need for blood products during liver surgeries.

Risk of Bleeding in End-Stage Liver Disease Patients Undergoing Cardiac Catheterization

Patients with end-stage liver disease frequently have baseline coagulopathies. The international normalized ratio is in common use for the estimation of bleeding tendency in such patients, especially those undergoing an invasive procedure like cardiac catheterization. The practice of international normalized ratio measurement-followed by pharmacologic (for example, vitamin K or fresh frozen plasma) or nonpharmacologic intervention-is still debatable. The results of multiple randomized trials have shown the superiority of the radial approach over femoral access in reducing catheterization bleeding. This reduction in bleeding in turn decreases the risk and cost of blood-product transfusion. However, there is little evidence regarding the use of the radial approach in the end-stage liver disease patient population specifically. In this review, we summarize the studies that have dealt with cardiac catheterization in patients who have end-stage liver disease. We also discuss the role of the current measurements that are used to reduce the risk of bleeding in these same patients.

Pediatric transplantation: managing bleeding

There has been extraordinary progress over the last half-century in the field of medical transplantation in which tissue, organs, or body parts from one human are placed into another. Solid organ transplants have allowed thousands of children with otherwise devastating inherited or acquired disorders to survive. Depending upon the clinical situation, there are many specific peri-transplant issues that must be carefully addressed to optimize outcomes. Although surgical, immunologic, and infectious concerns are usually in the forefront, important aspects regarding hemostasis frequently arise. The number of solid organs that can be successfully transplanted in children has expanded over the last decades and includes kidney, liver, heart, lung, intestine, pancreas, and thymus. Bleeding complications may occur in the setting of organ failure prior to transplantation, during the surgical procedure, or in the post-transplant setting, and can results in significant morbidity. This report will focus on preventing and managing non-surgical-related bleeding complications in children undergoing liver, heart, kidney transplantation, in whom there are often unique aspects of coagulation to be considered.

[Coagulation management in patients with liver disease]

BACKGROUND

End-stage liver disease is associated with complex alterations in hemostasis. Whereas prognosis is essentially affected by life-threatening bleeding complications in some patients, others, especially those with cholestatic liver diseases, suffer from thromboembolic complications. Standard laboratory values (SLVS; prothrombin time, activated partial thrombin time, platelet count) cannot sufficiently reflect the altered balance of pro- and anticoagulatory factors. Moreover, a couple of studies indicated that SLVS are not able to predict bleeding complications in patients with acute liver failure or decompensated liver cirrhosis.

DIAGNOSIS AND THERAPY

Use of bed-side coagulation diagnostics such as thrombelastometry/-graphy, detection of thrombocyte function by multiple electrode aggregometry and selective measurement of single factors allows a targeted and causal therapy of hepatic coagulopathies especially in the context of bleeding complications or surgical interventions. In recent years, coagulation management guided by these new devices has contributed to a reduction in transfusion of allogenic blood products, which may be associated with undesirable side effects.

DISCUSSION

The current review summarizes the complex pathophysiological alterations of hemostasis associated with advanced liver insufficiency and discusses recent upcoming diagnostics and coagulation management in this patient cohort.

Practice guidelines for perioperative blood management: an updated report by the American Society of Anesthesiologists Task Force on Perioperative Blood Management*

The American Society of Anesthesiologists Committee on Standards and Practice Parameters and the Task Force on Perioperative Blood Management presents an updated report of the Practice Guidelines for Perioperative Blood Management.

Supplemental Digital Content is available in the text.

Management of coagulation abnormalities in liver disease

Liver disease is characterized by changes in all phases of hemostasis. These hemostatic alterations were long considered to predispose patients with liver disease towards a bleeding tendency, as they are associated with prolonged conventional coagulation tests. However, these patients may also suffer from thrombotic complications, and we now know that the hemostatic system in patient with liver disease is, in fact, in a rebalanced state. In this review we discuss the concept of rebalanced hemostasis and its implications for clinical management of patients with liver disease. For instance, there is no evidence that the use of prophylactic blood product transfusion prior to invasive procedures reduces bleeding risk. Clinicians should also be aware of the possibility of thrombosis occurring in patients with a liver disease, and regular thrombosis prophylaxis should not be withheld in these patients.

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.

Monitoring and managing hepatic disease in anaesthesia

Patients with liver disease have multisystem organ dysfunction that leads to physiological perturbations ranging from hyperbilirubinaemia of no clinical consequence to severe coagulopathy and metabolic disarray. Patient-specific risk factors, clinical scoring systems, and surgical procedures stratify perioperative risk for these patients. The anaesthetic management of patients with hepatic dysfunction involves consideration of impaired drug metabolism, hyperdynamic circulation, perioperative hypoxaemia, bleeding, thrombosis, and hepatic encephalopathy.

Intraoperative care of the transplant patient

Patients undergoing abdominal organ transplantation have extensive comorbidities that can affect many organ systems including the cardiovascular system. Intraoperative anesthesia care can be very challenging and requires thorough understanding of the disease specific physiology as well as knowledge of the comorbidities and the surgical procedure. There is no approach to intraoperative anesthesia care that will work equally well for every center but standardization of protocols for each transplant center will improve patient care and safety and ultimately contributes to superior outcomes. In this article we provide background and suggestions that will help with the development of standardized protocols for intraoperative management.

Coagulation abnormalities in the cirrhotic patient

The clotting process is a dynamic array of multiple processes which can be described in four phases: platelet plug initiation and formation, clotting process propagation by the coagulation cascade, clotting termination by antithrombotic mechanisms and clot removal by fibrinolysis. The liver plays a central role in each of these phases of clotting process, as it synthesizes the majority of coagulation factors and proteins involved in fibrinolysis as well as thrombopoeitin, which is responsible for platelet production from megakaryocytes. Many pathological processes associated with cirrhosis, such as portal hypertension and endothelial dysfunction, as well as co-morbid conditions, may also alter the coagulation process. Consequently, patients with liver disease have a disturbed balance of procoagulant and anti-coagulant factors which deviates from the normal coagulation cascade. This situation poses an additional problem in the diagnostic and therapeutic approach to this group of patients, since traditional coagulation test may not be reliable for assessing bleeding or thrombotic risk and traditional transfusional strategies may not be applicable in cirrhotic patients. In this article, we review the pathophysiological bases of coagulation abnormalities, in cirrhotic patients, the diagnostic therapeutic strategies to be followed and its impact on the clinical outcome in the cirrhotic patient.

Recombinant activated factor VII in patients with acute liver failure with UNOS Status 1A: a single tertiary academic centre experience

BACKGROUND AND OBJECTIVES

Recombinant activated factor VII (rFVIIa) is often used in off-label indications, including many situations in which the patients are at risk of thrombosis. In this study, we retrospectively reviewed the use of rFVIIa in patients with acute liver failure - UNOS Status 1A (ALF-1A) to determine its efficacy and safety profile.

MATERIALS AND METHODS

Using the transplantation records, all adult patients with ALF-1A were identified from 6/2001 to 3/2009. From patients' medical charts, rFVIIa dose, blood component usage, short-term outcomes [length of intensive care unit (ICU) and hospital stay, ability to undergo orthotopic liver transplant (OLT) and in-hospital survival rate] and adverse events were examined.

RESULTS

Forty-two patients with ALF-1A were identified. Fifteen patients received rFVIIa with doses ranging between 24·4 μg/kg and 126·8 μg/kg. Three patients received two doses of rFVIIa. The age, baseline activated partial thromboplastin time (aPTT) and platelet (PLT) count were not statistically different between the group receiving rFVIIa versus the group that did not. However, the prothrombin time (PT) was significantly higher in the rFVIIa group. Although the rFVIIa group stayed in the ICU longer and required significant more blood products during admission, there was no statistical difference between the two groups in terms of length of hospital stay, ability to undergo OLT and survival rate. There was no increase in complications, including thrombosis, after receiving rFVIIa.

CONCLUSION

Recombinant activated factor VII (rFVIIa) appears to be safe in patients with ALF-1A, but to elucidate its full role, a randomized controlled trial would be ideal.