Antifibrinolytics in liver transplantation

Guidelines for the management of coagulation disorders in patients with cirrhosis

Coagulation management in the patient with cirrhosis has undergone a significant transformation since the beginning of this century, with the concept of a rebalancing between procoagulant and anticoagulant factors. The paradigm that patients with cirrhosis have a greater bleeding tendency has changed, as a result of this rebalancing. In addition, it has brought to light the presence of complications related to thrombotic events in this group of patients. These guidelines detail aspects related to pathophysiologic mechanisms that intervene in the maintenance of hemostasis in the patient with cirrhosis, the relevance of portal hypertension, mechanical factors for the development of bleeding, modifications in the hepatic synthesis of coagulation factors, and the changes in the reticuloendothelial system in acute hepatic decompensation and acute-on-chronic liver failure. They address new aspects related to the hemorrhagic complications in patients with cirrhosis, considering the risk for bleeding during diagnostic or therapeutic procedures, as well as the usefulness of different tools for diagnosing coagulation and recommendations on the pharmacologic treatment and blood-product transfusion in the context of hemorrhage. These guidelines also update the knowledge regarding hypercoagulability in the patient with cirrhosis, as well as the efficacy and safety of treatment with the different anticoagulation regimens. Lastly, they provide recommendations on coagulation management in the context of acute-on-chronic liver failure, acute liver decompensation, and specific aspects related to the patient undergoing liver transplantation.

Characteristics and Outcomes of Liver Transplantation Recipients after Tranexamic Acid Treatment and Platelet Transfusion: A Retrospective Single-Centre Experience

Background and Objectives: Patients undergoing liver transplantation (LT) often require increased blood product transfusion due to pre-existing coagulopathy and intraoperative fibrinolysis. Strategies to minimise intraoperative bleeding and subsequent blood product requirements include platelet transfusion and tranexamic acid (TXA). Prophylactic TXA administration has been shown to reduce bleeding and blood product requirements intraoperatively. However, its clinical use is still debated. The aim of this study was to report on a single-centre practice and analyse clinical characteristics and outcomes of LT recipients according to intraoperative treatment of TXA or platelet transfusion. Materials and Methods: This was a retrospective observational cohort study in which we reviewed 162 patients' records. Characteristics, intraoperative requirement of blood products, postoperative development of thrombosis and outcomes were compared between patients without or with intraoperative TXA treatment and without or with platelet transfusion. Results: Intraoperative treatment of TXA and platelets was 53% and 57.40%, respectively. Patients who required intraoperative administration of TXA or platelet transfusion also required more transfusion of blood products. Neither TXA nor platelet transfusion were associated with increased postoperative development of hepatic artery and portal vein thrombosis, 90-day mortality or graft loss. There was a significant increase in the median length of intensive care unit (ICU) stay in those who received platelet transfusion only (2.00 vs. 3.00 days; p = 0.021). Time to extubate was significantly different in both those who required TXA and platelet transfusion intraoperatively. Conclusions: Our analysis indicates that LT recipients still required copious intraoperative transfusion of blood products, despite the use of intraoperative TXA and platelets. Our findings have important implications for current transfusion practice in LT recipients and may guide clinicians to act upon these findings, which will support global efforts to encourage a wider use of TXA to reduce transfusion requirements, including platelets.

Tranexamic acid versus placebo to reduce perioperative blood transfusion in patients undergoing liver resection: protocol for the haemorrhage during liver resection tranexamic acid (HeLiX) randomised controlled trial

INTRODUCTION

Despite use of operative and non-operative interventions to reduce blood loss during liver resection, 20%-40% of patients receive a perioperative blood transfusion. Extensive intraoperative blood loss is a major risk factor for postoperative morbidity and mortality and receipt of blood transfusion is associated with serious risks including an association with long-term cancer recurrence and overall survival. In addition, blood products are scarce and associated with appreciable expense; decreasing blood transfusion requirements would therefore have health system benefits. Tranexamic acid (TXA), an antifibrinolytic, has been shown to reduce the probability of receiving a blood transfusion by one-third for patients undergoing cardiac or orthopaedic surgery. However, its applicability in liver resection has not been widely researched.

METHODS AND ANALYSIS

This protocol describes a prospective, blinded, randomised controlled trial being conducted at 10 sites in Canada and 1 in the USA. 1230 eligible and consenting participants will be randomised to one of two parallel groups: experimental (2 g of intravenous TXA) or placebo (saline) administered intraoperatively. The primary endpoint is receipt of blood transfusion within 7 days of surgery. Secondary outcomes include blood loss, postoperative complications, quality of life and 5-year disease-free and overall survival.

ETHICS AND DISSEMINATION

This trial has been approved by the research ethics boards at participating centres and Health Canada (parent control number 177992) and is currently enrolling participants. All participants will provide written informed consent. Results will be distributed widely through local and international meetings, presentation, publication and ClinicalTrials.gov.

TRIAL REGISTRATION NUMBER

NCT02261415.

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.

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.

A comparison of intra-operative blood loss and acid-base balance between vasopressor and inotrope strategy during living donor liver transplantation: a randomised, controlled study

Administration of vasopressors or inotropes during liver transplant surgery is almost universal, as this procedure is often accompanied by massive haemorrhage, acid-base imbalance, and cardiovascular instability. However, the actual agents that should be used and the choice between a vasopressor and an inotrope strategy are not clear from existing published evidence. In this prospective, randomised, controlled and single-blinded study, we compared the effects of a vasopressor strategy on intra-operative blood loss and acid-base status with those of an inotrope strategy during living donor liver transplantation. Seventy-six adult liver recipients with decompensated cirrhosis were randomly assigned to receive a continuous infusion of either phenylephrine at a dose of 0.3-0.4 μg.kg(-1).min(-1) or dopamine and/or dobutamine at 2-8 μg.kg(-1).min(-1) during surgery. Vascular resistance was higher over time in the phenylephrine group than in the dopamine/dobutamine group. Estimated blood loss was significantly lower in the phenylephrine group than in the dopamine/dobutamine group (mean (SD) 4.5 (1.8) l vs 6.1 (3.4) l, respectively, p=0.011). Patients in the phenylephrine group had lower lactate levels in the late pre-anhepatic and the early anhepatic phase and needed less bicarbonate administration than those in the dopamine/dobutamine group (median (IQR [range]) 40 (0-100 [0-160]) mEq vs 70 (40-163 [0-260]) mEq, respectively, p=0.018). Postoperative clinical outcomes and laboratory-measured hepatic and renal function did not differ between the groups. Increased vascular resistance and reduction of portal blood flow by intra-operative phenylephrine infusion is assumed to decrease the amount of intra-operative bleeding and thereby ameliorate the progression of lactic acidosis during liver transplant surgery.

Anesthesia care for liver transplantation

Intraoperative transfusion practices for liver transplantation have evolved dramatically since the first transplants of the 1960s. It is important for today's clinicians to be current in their understanding of how transplant patients should be managed with regard to their coagulation profile, volume status, and general hemodynamic state. The anesthesia team is presented with the unique task of manipulating this tenuous balance in a rapid and precise manner when managing patients undergoing liver transplantation. Although significant progress has been made in reducing blood product administration, it is still common to encounter large volume blood loss in these cases. Increasingly, clinicians are challenged to justify transfusion practices with a stronger evidentiary base. The current state of the literature for transfusion guidelines and blood product management in this particular patient subset will be discussed, as well as a variety of means (both pharmacologic and otherwise) used to reduce the need for transfusion. The aim was to review the latest evidence on these topics, as well as to highlight areas that need further clarification regarding their role in the optimal care of these patients.

Bleeding in liver surgery: prevention and treatment

Intraoperative blood loss and transfusion of blood products are negatively associated with postoperative outcome after liver surgery. Blood loss can be minimized by surgical methods, including vascular clamping techniques, the use of dissection devices, and the use of topical hemostatic agents. Preoperative correction of coagulation tests with blood products has not been shown to reduce intraoperative bleeding and it may, in fact, enhance the bleeding risk. Maintaining a low central venous pressure has been shown to be effective in reducing blood loss during partial liver resections, and volume contraction rather than prophylactic transfusion blood products seems justified in patients undergoing major liver surgery. Although antifibrinolytic drugs have proved to be effective in reducing blood loss during liver transplantation, systemic hemostatic drugs are of limited value in reducing blood loss in patients undergoing partial liver resections.

Perioperative renal protection

Acute kidney injury (AKI) is a significant cause of perioperative patient morbidity and mortality. The definition of AKI has recently changed and further research is underway to identify clinically relevant biomarkers to aid in the diagnosis of the syndrome. AKI is often multi-factorial in origin and patients with certain preoperative risk factors are at elevated risk of perioperative AKI. An anesthesiologist's main objective for perioperative renal protection is prevention by maintenance of euvolemia, preservation of adequate renal perfusion, and avoidance of nephrotoxins. This review will address the definition and diagnosis of AKI, identify patients at risk of AKI, and critically appraise management options for perioperative renal protection.