The prophylactic use of tranexamic acid and aprotinin in orthotopic liver transplantation: a comparative study

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.

New under the sun: ClotPro's ECA-test detects hyperfibrinolysis in a higher number of patients, more frequently and 9 min earlier

Liver diseases result in a re-balanced state of the haemostatic system with decreased haemostatic reserves. Increased fibrinolytic activity is commonly seen during liver transplants. The aim of this study was to assess whether ClotPro's ECA-test is able to detect hyperfibrinolysis earlier and with higher frequency than ClotPro's conventional viscoelastic assays for the intrinsic and the extrinsic coagulation pathway. From 25 liver transplant recipients, systemic blood samples were collected during surgery. Viscoelastic haemostatic assays with ClotPro's IN-test, EX-test and ECA-test were performed simultaneously from each blood sample. Hyperfibrinolysis was defined on the basis of the manufacturer's prespecified threshold value (maximal lysis >15%). The incidence of hyperfibrinolysis detected with each test was compared with the McNemar test. For each assay, lysis detection time (LDT) was calculated and analysed with the nonparametric Kruskal-Wallis test. A total of 125 tests were performed simultaneously. Compared with the IN-test and the EX-test, the ECA-test detected hyperfibrinolysis in significantly ( P  < 0.001) higher number of patients (9; 11; 14, respectively) and in more measurement points (14; 18; 28, respectively). The analysis of LDT values revealed significant superiority of the ECA-test to the IN-test ( P  = 0.046) and to the EX-test ( P  = 0.035), indicating the profibrinolytic state of the haemostasis 8.9 ± 0.65 and 8.7 ± 0.17 min earlier, respectively. These are preliminary results of the study NCT0424637. ClotPro's ECA-test appeared to detect fibrinolysis in a higher number of patients, more frequently, and the mean time of detection was 9 min earlier than that of the IN-test and the EX-test.

Synthesis and Hemostatic Activity of New Amide Derivatives

Eight dipeptides containing antifibrinolytic agents (tranexamic acid, aminocaproic acid, 4-(aminomethyl)benzoic acid, and glycine—natural amino acids) were synthesized in a three-step process with good or very good yields. DMT/NMM/TsO⁻ (4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium toluene-4-sulfonate) was used as a coupling reagent. Hemolysis tests were used to study the effects of the dipeptides on blood components. Blood plasma clotting tests were used to examine their effects on thrombin time (TT), prothrombin time (PT), and the activated partial thromboplastin time (aPTT). The level of hemolysis did not exceed 1%. In clotting tests, TT, PT, and aPTT did not differentiate any of the compounds. The prothrombin times for all amides 1–8 were similar. The obtained results in the presence of amides 1–4 and 8 were slightly lower than for the other compounds and the positive control, and they were similar to the results obtained for TA. In the case of amide 3, a significantly decreased aPTT was observed. The aPTTs observed for plasma treated with amide 3 and TA were comparable. In the case of amide 6 and 8, TT values significantly lower than for the other compounds were found. The clot formation and fibrinolysis (CFF) assay was used to assess the influence of the dipeptides on the blood plasma coagulation cascade and the fibrinolytic efficiency of the blood plasma. In the clot formation and fibrinolysis assay, amides 5 and 7 were among the most active compounds. The cytotoxicity and genotoxicity of the synthesized dipeptides were evaluated on the monocyte/macrophage peripheral blood cell line. The dipeptides did not cause hemolysis at any concentrations. They exhibited no significant cytotoxic effect on SC cells and did not induce significant DNA damage.

Clinical use of tranexamic acid: evidences and controversies

Tranexamic acid (TXA) significantly reduces blood loss in a wide range of surgical procedures and improves survival rates in obstetric and trauma patients with severe bleeding. Although it mainly acts as a fibrinolysis inhibitor, it also has an anti-inflammatory effect, and may help attenuate the systemic inflammatory response syndrome found in some cardiac surgery patients. However, the administration of high doses of TXA has been associated with seizures and other adverse effects that increase the cost of care, and the administration of TXA to reduce perioperative bleeding needs to be standardized. Tranexamic acid is generally well tolerated, and most adverse reactions are considered mild or moderate. Severe events are rare in clinical trials, and literature reviews have shown tranexamic acid to be safe in several different surgical procedures. However, after many years of experience with TXA in various fields, such as orthopedic surgery, clinicians are now querying whether the dosage, route and interval of administration currently used and the methods used to control and analyze the antifibrinolytic mechanism of TXA are really optimal. These issues need to be evaluated and reviewed using the latest evidence to improve the safety and effectiveness of TXA in treating intracranial hemorrhage and bleeding in procedures such as liver transplantation, and cardiac, trauma and obstetric surgery.

Tranexamic acid for the prevention and treatment of bleeding in surgery, trauma and bleeding disorders: a narrative review

OBJECTIVES

We review the evidence for tranexamic acid (TXA) for the treatment and prevention of bleeding caused by surgery, trauma and bleeding disorders. We highlight therapeutic areas where evidence is lacking and discuss safety issues, particularly the concern regarding thrombotic complications.

METHODS

An electronic search was performed in PubMed and the Cochrane Library to identify clinical trials, safety reports and review articles.

FINDINGS

TXA reduces bleeding in patients with menorrhagia, and in patients undergoing caesarian section, myomectomy, hysterectomy, orthopedic surgery, cardiac surgery, orthognathic surgery, rhinoplasty, and prostate surgery. For dental extractions in patients with bleeding disorders or taking antithrombotic drugs, as well as in cases of idiopathic epistaxis, tonsillectomy, liver transplantation and resection, nephrolithotomy, skin cancer surgery, burn wounds and skin grafting, there is moderate evidence that TXA is effective for reducing bleeding. TXA was not effective in reducing bleeding in traumatic brain injury and upper and lower gastrointestinal bleeding. TXA reduces mortality in patients suffering from trauma and postpartum hemorrhage. For many of these indications, there is no consensus about the optimal TXA dose. With certain dosages and with certain indications TXA can cause harm, such as an increased risk of seizures after high TXA doses with brain injury and cardiac surgery, and an increased mortality after delayed administration of TXA for trauma events or postpartum hemorrhage. Whereas most trials did not signal an increased risk for thrombotic events, some trials reported an increased rate of thrombotic complications with the use of TXA for gastro-intestinal bleeding and trauma.

CONCLUSIONS

TXA has well-documented beneficial effects in many clinical indications. Identifying these indications and the optimal dose and timing to minimize risk of seizures or thromboembolic events is work in progress.

Altered Fibrinolysis during and after Surgery

Major surgery induces hemostatic changes related to surgical stress, tissue destruction, and inflammatory reactions. These changes involve a shift of volume from extravascular space to intravascular and interstitial spaces, a "physiologic" hemodilution of coagulation proteins, and an increase of plasmatic fibrinogen concentration and platelets. Increases in fibrinogen and platelets together with a simultaneous dilution of pro- and anticoagulant factors and development of a hypofibrinolytic status result in a postoperative hypercoagulable state. This profile is accentuated in more extensive surgery, but the balance can shift toward hemorrhagic tendency in specific types of surgeries, for example, in prolonged cardiopulmonary bypass or in patients with comorbidities, especially liver diseases, sepsis, and hematological disorders. Also, acquired coagulopathy can develop in patients with trauma, during obstetric complications, and during major surgery as a result of excessive blood loss and subsequent consumption of coagulation factors as well as hemodilution. In addition, an increasing number of patients receive anticoagulants and antiplatelet drugs preoperatively that might influence the response to surgical hemostasis. This review focuses on those situations that may change normal hemostasis and coagulation during surgery, producing both hyperfibrinolysis and hypofibrinolysis, such as overcorrection with coagulation factors, bleeding and hyperfibrinolysis that may occur with extracorporeal circulation and high aortic-portal-vena cava clamps, and hyperfibrinolysis related to severe maintained hemodynamic disturbances. We also evaluate the role of tranexamic acid for prophylaxis and treatment in different surgical settings, and finally the value of point-of-care testing in the operating room is commented with regard to investigation of fibrinolysis.

The efficacy and safety of high-dose tranexamic acid in adolescent idiopathic scoliosis: a meta-analysis

Background

This study aimed to evaluate the efficacy and safety of using high-dose intravenous tranexamic acid (TXA) to reduce blood loss in idiopathic scoliosis surgery.

Methods

This study was a meta-analysis, which consisted of retrospective cohort studies (RCSs) and randomized control trials (RCTs) found by searching electronic databases, namely PubMed, Web of Science, The Cochrane Central Register of Controlled Trials (CENTRAL), and the Google Scholar Database, dating from 1960 to 2019. The points of interest included total blood loss, a need for transfusion and transfusion criteria, surgery time, and the evidence of intraoperative and postoperative complications, such as seizures or thromboembolic events. The weighted mean differences (WMD) and 95% confidence interval (CI) of blood loss in the TXA intervention group compared to the control or placebo group were extracted and combined using the random effects model.

Results

In this meta-analysis, there was a total of three RCSs and two RCTs, which involved 334 patients. The results showed that blood loss is significantly reduced, with a weighted mean difference in the TXA group (WMD = − 525.14, P = 0.0000, CI ranged from − 839.83, − 210.44, I² = 82%). Heterogeneity was assessed using the random effects model.

Conclusions

A high dose of intravenous TXA reduced blood loss during adolescent idiopathic scoliosis surgery and did not lead to any significant thromboembolic event. Therefore, a high dose appears to be effective and safe for adolescent idiopathic scoliosis surgery. However, more high-quality research based on larger randomized controlled trials is still needed.

Point-of-care haemostasis monitoring during liver transplantation is cost effective

Background Optimal haemostasis management in orthotropic liver transplant (OLT) could reduce blood loss and transfusion volume, improve patient outcomes and reduce cost. Methods We performed a study including 336 OLTs to evaluate the clinical and cost effectiveness of a new point-of-care (POC)-based haemostatic management approach in OLT patients. Results In terms of health benefit we found that the new approach showed a significant reduction in transfusion requirements (red blood cell transfusion units were reduced from 5.3±4.6 to 2.8±2.9 [p<0.001], free frozen plasma from 3.1±3.3 to 0.4±1.0 [p<0.001] and platelets from 2.9±3.9 to 0.4±0.9 [p<0.001], transfusion avoidance, 9.7% vs. 29.1% [p<0.001] and massive transfusion, 14.5% vs. 3.8% [p=0.001]); we also found a significant improvement in patient outcomes, such, reoperation for bleeding or acute-kidney-failure (8.3% vs. 2.4%, p=0.015; 33.6% vs. 5.4%, p<0.001), with a significant reduction in the length of the hospital total stay (40.6±13.8 days vs. 38.2±14.4 days, p=0.001). The lowest cost incurred was observed with the new approach (€73,038.80 vs. €158,912.90) with significant patient saving associated to transfusion avoidance (€1278.36), ICU-stay (€3037.26), total-stay (€3800.76) and reoperation for bleeding (€80,899.64). Conclusions POC haemostatic monitoring during OLT is cost effective.

Exclusion criteria and adverse events in perioperative trials of tranexamic acid: a systematic review and meta-analysis

BACKGROUND

Tranexamic acid (TXA) is an inexpensive therapy effective at minimizing perioperative blood loss and transfusion. However, it remains underutilized due to safety concerns. To date, no evidence-based guidelines exist identifying which patients should not receive TXA therapy. This study determined patient groups for whom safety information regarding TXA is lacking due to common exclusion from perioperative TXA trials.

STUDY DESIGN AND METHODS

A systematic review searching the databases Medline, EMBASE, CENTRAL, and Clinicaltrials.gov was performed. Randomized controlled trials (RCTs) administering systemic TXA perioperatively to elective or emergent surgery patients were eligible. Our primary outcome was to describe exclusion criteria of RCTs, and the secondary outcome was TXA safety. A descriptive synthesis of exclusion criteria was performed, and TXA safety was assessed by meta-analysis.

RESULTS

A total of 268 eligible RCTs were included. Meta-analysis showed that systemic TXA did not increase risk of adverse events compared to placebo or no intervention (relative risk, 1.05; 95% confidence interval, 0.99-1.12). Patient groups commonly excluded from perioperative TXA trials, and thus potentially lacking TXA safety data, were those with major comorbidities, a history of thromboembolism, medication use affecting coagulation, TXA allergy, and coagulopathy. Exclusion of patients with major comorbidities may not be necessary; we showed that the risk of adverse events was similar in studies that excluded patients with major comorbidities and those that did not.

CONCLUSION

Sufficient evidence exists to develop perioperative guidelines for TXA use in many populations. Further studies evaluating perioperative TXA use in patients with a history of thromboembolism are warranted.

Use of Rotational Thromboelastometry in Liver Transplantation Is Associated With Reduced Transfusion Requirements

OBJECTIVES

Increased transfusion requirements in liver transplantation have been reported to be associated with worsened outcomes, more frequent reinterventions, and higher expenses. Anesthesiologists might counteract this through improved coagulation management. We evaluated the effects of rotational thromboelastometry on transfusion and coagulation product requirements and on outcome measurements.

MATERIALS AND METHODS

Patients who were 14 years or older and who were undergoing liver transplant at Hannover Medical School between January 2005 and December 2009 were included in this retrospective analysis. Demographic, clinical, and laboratory data, use of rotational thromboelastometry, intraoperative need for blood or coagulation products and antifibrinolytic substances, and clinical course were recorded. Correlations were examined using appropriate statistical tests.

RESULTS

Our study included 413 patients. Use of rotational thromboelastometry was associated with less frequent intraoperative administration of red blood cell concentrates, fresh frozen plasma, platelet concentrates, prothrombin complex concentrates, and antithrombin concentrates (all P < .05). In addition, univariate and multivariate tests showed that rotational thromboelastometry was correlated with decreased need for red blood cell concentrates and fresh frozen plasma (all P < .05). Intraoperative administration rates of antifibrinolytic substances and fibrinogen concentrate were significantly increased in patients who received rotational thromboelastometry monitoring (both P < .05). However, use of rotational thromboelastometry was not associated with massive transfusion rates (> 10 units vs less), clinical outcome, or length of stay in the intensive care unit (all P > .05).

CONCLUSIONS

Use of rotational thromboelastometry during liver transplant may reduce the need for intraoperative transfusion and coagulation products. Relevant effects of rotational thromboelastometry on patient outcomes or lengths of stay in the intensive care unit could not be ascertained. However, readjustment of therapeutic thresholds may improve the clinical impact.

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.

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.

Major liver resection, systemic fibrinolytic activity, and the impact of tranexamic acid

BACKGROUND

Hyperfibrinolysis may occur due to systemic inflammation or hepatic injury that occurs during liver resection. Tranexamic acid (TXA) is an antifibrinolytic agent that decreases bleeding in various settings, but has not been well studied in patients undergoing liver resection.

METHODS

In this prospective, phase II trial, 18 patients undergoing major liver resection were sequentially assigned to one of three cohorts: (i) Control (no TXA); (ii) TXA Dose I - 1 g bolus followed by 1 g infusion over 8 h; (iii) TXA Dose II - 1 g bolus followed by 10 mg/kg/hr until the end of surgery. Serial blood samples were collected for thromboelastography (TEG), coagulation components and TXA concentration.

RESULTS

No abnormalities in hemostatic function were identified on TEG. PAP complex levels increased to peak at 1106 μg/L (normal 0-512 μg/L) following parenchymal transection, then decreased to baseline by the morning following surgery. TXA reached stable, therapeutic concentrations early in both dosing regimens. There were no differences between patients based on TXA.

CONCLUSIONS

There is no thromboelastographic evidence of hyperfibrinolysis in patients undergoing major liver resection. TXA does not influence the change in systemic fibrinolysis; it may reduce bleeding through a different mechanism of action. Registered with ClinicalTrials.gov: NCT01651182.

Using tranexamic acid soaked absorbable gelatin sponge following complex posterior lumbar spine surgery: A randomized control trial

OBJECTIVES

This paper aims to determine whether the use of Tranexemic Acid (TXA) - soaked absorbable gelatin sponge could more effectively reduce post-operative blood loss and blood transfusion requirements among low-risk adult patients undergoing lumbar spine surgery.

METHODS

A total of 90 consecutive patients undergoing surgery for multilevel posterior lumbar degenerative procedures were prospectively randomized into one of three groups: - TXA Soaked Gelfoam group, absorbable gelatin sponge group or control group. Demographic distribution, total drain output, blood transfusion requirement, length of hospital stay, the number of readmissions, and postoperative complications were analyzed.

RESULTS

In the TXA Soaked Gelfoam, Gelfoam, and control groups, the respective hemovac drainage at the first 8h postoperatively was 81.06±61.21, 166.73±76.76, and 155.67±92.94ml respectively. The second 8h period drainage for the same groups postoperatively was 46.67±40.09, 55.10±43.43, and 82.50±56.67ml and 23.73±25.56, 32.43±25.81 and 44.20±32.44ml for the third 8h period postoperatively. The duration of the post-operative drain left in the TXA Soaked Gelfoam group was significantly shorter than the Gelfoam and control groups (p=0.019 and 0.000, respectively). The TXA Soaked Gelfoam and Gelfoam also had a significantly shorter hospital stay than the control group (p=0.014, and 0.036, respectively). No patient developed adverse reactions attributable to the tranexamic acid soaked absorbable gelatin sponge.

CONCLUSIONS

TXA-soaked absorbable gelatin sponge is a safe, effective treatment for reduction of post-operative blood loss and blood transfusions among low-risk adult patients undergoing lumbar spine surgery.

The pathophysiology of thrombocytopenia in chronic liver disease

Thrombocytopenia is the most common hematological abnormality encountered in patients with chronic liver disease (CLD). In addition to being an indicator of advanced disease and poor prognosis, it frequently prevents crucial interventions. Historically, thrombocytopenia has been attributed to hypersplenism, which is the increased pooling of platelets in a spleen enlarged by congestive splenomegaly secondary to portal hypertension. Over the past decade, however, there have been significant advances in the understanding of thrombopoiesis, which, in turn, has led to an improved understanding of thrombocytopenia in cirrhosis. Multiple factors contribute to the development of thrombocytopenia and these can broadly be divided into those that cause decreased production, splenic sequestration, and increased destruction. Depressed thrombopoietin levels in CLD, together with direct bone marrow suppression, result in a reduced rate of platelet production. Thrombopoietin regulates both platelet production and maturation and is impaired in CLD. Bone marrow suppression can be caused by viruses, alcohol, iron overload, and medications. Splenic sequestration results from hypersplenism. The increased rate of platelet destruction in cirrhosis also occurs through a number of pathways: increased shear stress, increased fibrinolysis, bacterial translocation, and infection result in an increased rate of platelet aggregation, while autoimmune disease and raised titers of antiplatelet immunoglobulin result in the immunologic destruction of platelets. An in-depth understanding of the complex pathophysiology of the thrombocytopenia of CLD is crucial when considering treatment strategies. This review outlines the recent advances in our understanding of thrombocytopenia in cirrhosis and CLD.

Two Doses of Tranexamic Acid Reduce Blood Transfusion in Complex Spine Surgery: A Prospective Randomized Study

STUDY DESIGN

Prospective, double-blinded, randomized controlled study.

OBJECTIVE

To determine whether the use of 2 doses of tranexamic acid (TXA) can reduce perioperative blood loss and blood transfusions in low-risk adult patients undergoing complex laminectomy.

SUMMARY OF BACKGROUND DATA

Complex laminectomy (multilevel laminectomy or laminectomy and instrumentation) is a procedure with a medium risk of blood loss, which may require allogeneic blood transfusion. Previous studies of TXA showed its inconsistent effectiveness in reducing blood loss during spine surgery. The negative results may stem from ineffective use of a single dose of TXA during long and complex operations.

METHODS

80 adult (18-65 yr old) patients in Siriraj Hospital, Mahidol University, Thailand were enrolled and allocated into 2 groups (40 patients in each group) by computer-generated randomization. Patients with history of thromboembolic diseases were excluded. Anesthesiologists in charge and patients were blinded. Group I received 0.9% NaCl (NSS) or placebo and group II received 2 doses (15 mg/kg) of TXA. The first dose was administered before anesthesia induction and the second dose, after 3 hours. The assessed outcomes were the amount of perioperative blood loss and the incidence of blood transfusions.

RESULTS

78 patients were analyzed (1 patient in each group was excluded) with 39 patients randomized to each group. There were no differences in patient demographics and pre and postoperative hematocrit levels. The total blood loss in the control group (NSS) was higher [900 (160, 4150) mL] than in the TXA group [600 (200, 4750) mL]. Patients in the control group received more crystalloid, colloid, and packed red blood cell transfusions. Within 24 hours, we observed a 64.6% reduction of blood transfusions (43.5% vs.15.4%, P = 0.006). No serious thromboembolic complications occurred.

CONCLUSION

2 effective doses (15 mg/kg) of TXA can reduce blood loss and transfusions in low-risk adults undergoing complex spine surgery.

LEVEL OF EVIDENCE

1.

Point-of-care haemostasis monitoring during liver transplantation reduces transfusion requirements and improves patient outcome

BACKGROUND

Optimal haemostasis management can improve patient outcomes and reduce blood loss and transfusion volume in orthotopic-liver-transplant (OLT).

METHODS

We performed a prospective study including 200 consecutive OLTs. The first 100 patients were treated according to the clinic's standards and the next 100 patients were treated using the new point-of-care (POC)-based haemostasis management strategy. Transfusion parameters and other outcomes were compared between groups.

RESULTS

Transfusion requirements were reduced in the POC group. The median and IQR of red-blood-cells (RBC) transfusion units were reduced from 5 [2-8] to 3 [0-5] (p < 0.001), plasma from 2 [0-4] to 0 (p < 0.001), and platelets from 1 [0-4] to 0 [0-1] (p < 0.001), into the POC group only four patients received tranexamic acid and fibrinogen transfusion rate was 1.13 ± 1.44 g (p = 0.001). We also improved the incidence of transfusion avoidance, 5% vs. 24% (p < 0.001) and reduced the incidence of massive transfusion (defined as the transfusion of more than 10 RBC units), 13% vs. 2% (p = 0.005). We also observed a relationship between RBC transfusion requirements and preoperative haemoglobin, and between platelet transfusion and preoperative fibrinogen levels. The incidence of postoperative complications, such as, reoperation for bleeding, acute-kidney-failure or haemodynamic instability was significantly lower (13.0% vs. 5%, p = 0.048, 17% vs. 2%, p < 0.001, and 29% vs. 16%, p = 0.028). Overall, blood product transfusion was associated with increased risk of postoperative complications.

CONCLUSIONS

A haemostatic therapy algorithm based on POC monitoring reduced transfusion and improved outcome in OLT.

Risk Factors Associated with Reoperation for Bleeding following Liver Transplantation

Introduction. This study's objective was to identify risk factors associated with reoperation for bleeding following liver transplantation (LTx). Methods. A retrospective study was performed at a single institution between 2001 and 2012. Operative reports were used to identify patients who underwent reoperation for bleeding within 2 weeks following LTx (operations for nonbleeding etiologies were excluded). Results. Reoperation for bleeding was observed in 101/928 (10.8%) of LTx patients. The following characteristics were associated with reoperation on multivariable analysis: recipient MELD score (OR 1.06/MELD unit, 95% CI 1.03, 1.09), number of platelets transfused (OR 0.73/platelet unit, 95% CI 0.58, 0.91), and aminocaproic acid utilization (OR 0.46, 95% CI 0.27, 0.80). LTx patients who underwent reoperation for bleeding had a longer ICU stay (5 days ± 7 versus 2 days ± 3, P < 0.001) and hospitalization (18 days ± 9 versus 10 days ± 18, P < 0.001). The risk of death increased in patients who underwent reoperation for bleeding (HR 1.89, 95% CI 1.26, 2.85). Conclusion. Reoperation for bleeding following LTx was associated with increased resource utilization and recipient mortality. A lower threshold for intraoperative platelet transfusion and antifibrinolytics, especially in patients with high lab-MELD score, may decrease the incidence of reoperation for bleeding following LTx.

Epsilon-aminocaproic acid improves postrecirculation hemodynamics by reducing intraliver activated protein C consumption in orthotopic liver transplantation

BACKGROUND

Activated protein C (APC) is related to regulating the inflammatory response and hemodynamic stability upon reperfusion in cardiac operations and orthotopic liver transplantation (OLT). Epsilon-aminocaproic acid (EACA) is frequently used to treat fibrinolysis during OLT. It also has inhibitory effects related to the inflammatory response. However, it remains to be determined whether EACA can attenuate intraliver APC consumption and improve hemodynamic stability after reperfusion during OLT.

METHODS

Fifty-nine recipients were randomized to receive either EACA (150 mg kg(-1) given intravenously prior to incision, followed by 15 mg kg(-1) h(-1) infusion until 2 h after the graft reperfusion) or the same volume of saline. Blood samples to assess plasma APC and protein C were obtained immediately before and after reperfusion from the inferior caval effluent or the portal veins for calculation of transliver differences (Δ). Hemodynamics and vasoactive medication use during the reperfusion period were observed in both groups.

RESULTS

No transhepatic changes in protein C were found in either group. Immediately after reperfusion, a marked intraliver consumption of APC was noted in all recipients (P < 0.001), and intraliver consumption of APC in the control group was greater than that in the EACA-treated group (P < 0.05). Fewer requirements for vasoactive medication use after reperfusion and better initial graft function were noted in the EACA-treated group (P < 0.05).

CONCLUSIONS

EACA can attenuate intraliver APC consumption and improve hemodynamic stability after reperfusion and initial graft function during OLT.

Antifibrinolytic agents in current anaesthetic practice

Antifibrinolytic drugs have become almost ubiquitous in their use during major surgery when bleeding is expected or commonplace. Inhibition of the fibrinolytic pathway after tissue injury has been consistently shown to reduce postoperative or traumatic bleeding. There is also some evidence for a reduction of perioperative blood transfusion. However, evidence of complications associated with exaggerated thrombosis also exists, although this appears to be influenced by the choice of the individual agent and the dose administered. There is controversy over the use of the serine protease inhibitor aprotinin, whose license was recently withdrawn but may shortly become available on the market again. In the UK, tranexamic acid, a tissue plasminogen and plasmin inhibitor, is most commonly used, with evidence for benefit in cardiac, orthopaedic, urological, gynaecological, and obstetric surgery. In the USA, ε-aminocaproic acid, which also inhibits plasmin, is commonly used. We have reviewed the current literature for this increasingly popular class of drugs to support clinical judgement in daily anaesthetic practice.

Blood loss, predictors of bleeding, transfusion practice and strategies of blood cell salvaging during liver transplantation

Blood loss during liver transplantation (OLTx) is a common consequence of pre-existing abnormalities of the hemostatic system, portal hypertension with multiple collateral vessels, portal vein thrombosis, previous abdominal surgery, splenomegaly, and poor “functional” recovery of the new liver. The intrinsic coagulopathic features of end stage cirrhosis along with surgical technical difficulties make transfusion-free liver transplantation a major challenge, and, despite the improvements in understanding of intraoperative coagulation profiles and strategies to control blood loss, the requirements for blood or blood products remains high. The impact of blood transfusion has been shown to be significant and independent of other well-known predictors of posttransplant-outcome. Negative effects on immunomodulation and an increased risk of postoperative complications and mortality have been repeatedly demonstrated. Isovolemic hemodilution, the extensive utilization of thromboelastogram and the use of autotransfusion devices are among the commonly adopted procedures to limit the amount of blood transfusion. The use of intraoperative blood salvage and autologous blood transfusion should still be considered an important method to reduce the need for allogenic blood and the associated complications. In this article we report on the common preoperative and intraoperative factors contributing to blood loss, intraoperative transfusion practices, anesthesiologic and surgical strategies to prevent blood loss, and on intraoperative blood salvaging techniques and autologous blood transfusion. Even though the advances in surgical technique and anesthetic management, as well as a better understanding of the risk factors, have resulted in a steady decrease in intraoperative bleeding, most patients still bleed extensively. Blood transfusion therapy is still a critical feature during OLTx and various studies have shown a large variability in the use of blood products among different centers and even among individual anesthesiologists within the same center. Unfortunately, despite the large number of OLTx performed each year, there is still paucity of large randomized, multicentre, and controlled studies which indicate how to prevent bleeding, the transfusion needs and thresholds, and the “evidence based” perioperative strategies to reduce the amount of transfusion.

Coagulopathy management in liver transplantation

Risk of bleeding and transfusion in liver transplantation is determined by age, severity of liver disease, as well as hemoglobin and plasma fibrinogen values. During the hepatectomy and the anhepatic phase, the coagulopathy is related to a decrease in clotting factors caused by surgical bleeding, facilitated by the increased portal hypertension and esophageal-gastric venous distension. Corrections of hematologic disturbances by administration of large volumes of crystalloid, colloid, or blood products may worsen the coagulopathy. Also, impaired clearance of fibrinolytic enzymes released from damaged cells can lead to primary fibrinolysis. At time of graft reperfusion further deterioration may occur as characterized by global reduction among all coagulation factors, decreased plasminogen activator inhibitor factors, and simultaneous generation of tissue plasminogen activator. In situations with inherent risk of bleeding, hypofibrinogenemia must be corrected. Concern about unwanted events is a major limitation of preventive therapy. There is some evidence for the efficacy of antifibrinolytic drugs to reduce red blood cell requirements. A guide for antifibrinolytic therapy are clot firmness in trhomboelastometry or alternatively, diffuse bleeding associated to a fibrinogen value less than 1 g/L. Because thrombin generation is limited in severe thrombocytopenia, platelet administration is recommended when active bleeding coexists with a platelet count below 50,000/mm(3). When the administration of hemoderivates and antifibrinolytic drugs does not correct severe bleeding, consumption coagulopathy and secondary fibrinolysis should be suspected. Treatment of affected patients should be based upon correcting the underlying cause, mostly related to tissue hypoxia due to critical hypoperfusion.

Anaesthesia for Living Related Liver Transplantation

With the greater success of liver transplantation, livers from deceased donors are insufficient to meet the need for livers required for transplantation. In various parts of Asia, living related liver transplantation is the treatment for patients with end-stage liver disease. An overview of anaesthesia for both the donor and the recipient is described. Controversies involving epidural anaesthesia, blood loss prevention and blood conservation techniques in the donor are discussed. Various aspects in the anaesthetic management of the recipient are also looked at.

Tranexamic acid: a review of its use in the treatment of hyperfibrinolysis

Tranexamic acid, a synthetic derivative of the amino acid lysine, is an antifibrinolytic agent that acts by binding to plasminogen and blocking the interaction of plasmin(ogen) with fibrin, thereby preventing dissolution of the fibrin clot. Tranexamic acid (Transamin®) is indicated in Japan for use in certain conditions with abnormal bleeding or bleeding tendencies in which local or systemic hyperfibrinolysis is considered to be involved. This article reviews the efficacy and tolerability of tranexamic acid in conditions amenable to antifibrinolytic therapy and briefly overviews the pharmacological properties of the drug. In large, randomized controlled trials, tranexamic acid generally significantly reduced perioperative blood loss compared with placebo in a variety of surgical procedures, including cardiac surgery with or without cardiopulmonary bypass, total hip and knee replacement and prostatectomy. In many instances, tranexamic acid also reduced transfusion requirements associated with surgery. It also reduced blood loss in gynaecological bleeding disorders, such as heavy menstrual bleeding, postpartum haemorrhage and bleeding irregularities caused by contraceptive implants. Tranexamic acid significantly reduced all-cause mortality and death due to bleeding in trauma patients with significant bleeding, particularly when administered early after injury. It was also effective in traumatic hyphaema, gastrointestinal bleeding and hereditary angioneurotic oedema. While it reduces rebleeding in subarachnoid haemorrhage, it may increase ischaemic complications. Pharmacoeconomic analyses predicted that tranexamic acid use in surgery and trauma would be very cost effective and potentially life saving. In direct comparisons with other marketed agents, tranexamic acid was at least as effective as ε-aminocaproic acid and more effective than desmopressin in surgical procedures. It was more effective than desmopressin, etamsylate, flurbiprofen, mefenamic acid and norethisterone, but less effective than the levonorgestrel-releasing intra-uterine device in heavy menstrual bleeding and was as effective as prednisolone in traumatic hyphaema. Tranexamic acid was generally well tolerated. Most adverse events in clinical trials were of mild or moderate severity; severe or serious events were rare. Therefore, while high-quality published evidence is limited for some approved indications, tranexamic acid is an effective and well tolerated antifibrinolytic agent.

Liver transplantation in Indian Armed Forces-initial experience

BACKGROUND

This study retrospectively analyses the initial experience of liver transplantation (LT) in the Indian Armed Forces.

METHODS

Fifty-three patients underwent LT at Army Hospital (R&R) Delhi Cantt. between March 2007 and March 2011. Of these 35 patients underwent deceased donor liver transplantation (DDLT) and living donor liver transplantation (LDLT) was carried out in 18 patients. The surgical techniques, complications and mortality were analysed.

RESULTS

A high consent rate of 35.9% for organ donation was achieved by the Armed Forces Organ Retrieval and Transplantation Authority (AORTA). Biliary complications occurred in five patients (9.4%). However, most of them could be managed by endoscopic interventions. Hepatic artery thrombosis (HAT) occurred in five patients (9.4%). Of these, two DDLT grafts were revascularised following HAT, by creating extra-anatomic arterial conduits with excellent outcome. The overall mortality was 18.8% (n = 10). There was no significant difference in the overall complications or mortality in patients undergoing DDLT or LDLT.

CONCLUSION

The overall survival and morbidity in this study is comparable to those from other centres. Urgent revascularisation of grafts following HAT should be attempted as it can salvage grafts with satisfactory outcome. There is a reduction in the incidence of biliary complications with refinements in surgical techniques.

Comparison of aprotinin and tranexamic acid in adult scoliosis correction surgery

PURPOSE

A retrospective review of consecutive adult patients undergoing scoliosis correction surgery was performed to compare the effects of aprotinin and tranexamic acid in blood conservation and to define a comprehensive blood conservation strategy for such surgery.

METHODS

Medical records of all patients who underwent scoliosis correction surgery in this unit between January 2003 and December 2008 were reviewed. The patients were divided into three cohorts: group 1 receiving no antifibrinolytics, group 2 aprotinin and group 3 tranexamic acid. Information was collected regarding number of vertebral levels fused, pre- and post-operative haemoglobin, intra-operative blood loss and peri-operative autologous and allogenic blood transfusion performed.

RESULTS

Aprotinin was used in 28 patients (38%), tranexamic acid in 26 (36%), while 19 (26%) received no antifibrinolytics. 21 patients had anterior surgery, 34 patients had posterior surgery and 18 had combined anterior and posterior procedures. Mean blood loss in the patients who received aprotinin and tranexamic acid was 710 and 738 ml, respectively. This was significantly less than the patients receiving no antifibrinolytics (972 ml, p = 0.037). Blood transfusion was required in only two patients undergoing anterior correction surgery.

CONCLUSION

Aprotinin and tranexamic acid reduce blood loss in adult spinal deformity correction surgery. With aprotinin being unavailable for clinical use, we recommend the use of tranexamic acid along with other blood conservation measures for adult spinal deformity correction surgery.

[Anesthesia in the patient with impaired liver function]

We review information on impaired liver function, focusing on concepts relevant to anesthesia and postoperative recovery. The effects of impaired function are analyzed by systems of the body, with attention to the complications the patient with liver cirrhosis may develop according to type of surgery. Approaches to correcting coagulation disorders in the cirrhotic patient are particularly controversial because an increase in volume may be a factor in bleeding owing to increased portal venous pressure and imbalances in the factors that favor or inhibit coagulation. Perioperative morbidity and mortality correlate closely to Child-Pugh class and the score derived from the model for end-stage liver disease (MELD). Patients in Child class A are at moderate risk and surgery is therefore not contraindicated. Patients in Child class C or with a MELD score over 20, on the other hand, are at high risk and should not undergo elective surgical procedures. Abdominal surgery is generally considered to put patients with impaired liver function at high risk because it causes changes in hepatic blood flow and increases intraoperative bleeding because of high portal venous pressures.

Methods to decrease blood loss and transfusion requirements for liver transplantation

BACKGROUND

Excessive blood loss and increased blood transfusion requirements may have significant impact on the short-term and long-term outcomes after liver transplantation.

OBJECTIVES

To compare the potential benefits and harms of different methods of decreasing blood loss and blood transfusion requirements during liver transplantation.

SEARCH METHODS

We searched The Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and metaRegister of Controlled Trials until September 2011.

SELECTION CRITERIA

We included all randomised clinical trials that were performed to compare various methods of decreasing blood loss and blood transfusion requirements during liver transplantation.

DATA COLLECTION AND ANALYSIS

Two authors independently identified the trials and extracted the data. We analysed the data with both the fixed-effect and the random-effects model using RevMan Analysis. For each outcome we calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI) based on available data analysis. We also conducted network meta-analysis.

MAIN RESULTS

We included 33 trials involving 1913 patients. The sample size in the trials varied from 8 to 209 participants. The interventions included pharmacological interventions (aprotinin, tranexamic acid, epsilon amino caproic acid, antithrombin 3, recombinant factor (rFvIIa), oestrogen, prostaglandin, epinephrine), blood substitutes (blood components rather than whole blood, hydroxy-ethyl starch, thromboelastography), and cardiovascular interventions (low central venous pressure). All the trials were of high risk of bias. Primary outcomes were reported in at least two trials for the following comparisons: aprotinin versus control, tranexamic acid versus control, recombinant factor VIIa (rFVIIa) versus control, and tranexamic acid versus aprotinin. There were no significant differences in the 60-day mortality (3 trials; 6/161 (3.7%) in the aprotinin group versus 8/119 (6.7%) in the control group; RR 0.52; 95% CI 0.18 to 1.45), primary graft non-function (2 trials; 0/128 (0.0%) in the aprotinin group versus 4/89 (4.5%) in the control group; RR 0.15; 95% CI 0.02 to 1.25), retransplantation (3 trials; 2/256 (0.8%) in the aprotinin group versus 12/178 (6.7%) in the control group; RR 0.21; 95% CI 0.02 to 1.79), or thromboembolic episodes (3 trials; 4/161 (2.5%) in the aprotinin group versus 5/119 (4.2%) in the control group; RR 0.59; 95% CI 0.19 to 1.84) between the aprotinin and control groups. There were no significant differences in the 60-day mortality (3 trials; 4/83 (4.8%) in the tranexamic acid group versus 5/56 (8.9%) in the control group; RR 0.55; 95% CI 0.17 to 1.76), retransplantation (2 trials; 3/41 (7.3%) in the tranexamic acid group versus 3/36 (8.3%) in the control group; RR 0.79; 95% CI 0.18 to 3.48), or thromboembolic episodes (5 trials; 5/103 (4.9%) in the tranexamic acid group versus 1/76 (1.3%) in the control group; RR 2.20; 95% CI 0.38 to 12.64) between the tranexamic acid and control groups. There were no significant differences in the 60-day mortality (3 trials; 8/195 (4.1%) in the recombinant factor VIIa (rFVIIa) group versus 2/91 (2.2%) in the control group; RR 1.51; 95% CI 0.33 to 6.95), thromboembolic episodes (2 trials; 24/185 (13.0%) in the rFVIIa group versus 8/81 (9.9%) in the control group; RR 1.38; 95% CI 0.65 to 2.91), or serious adverse events (2 trials; 90/185 (48.6%) in the rFVIIa group versus 30/81 (37.0%) in the control group; RR 1.30; 95% CI 0.94 to 1.78) between the rFVIIa and control groups. There were no significant differences in the 60-day mortality (2 trials; 6/91 (6.6%) in the tranexamic acid group versus 1/87 (1.1%) in the aprotinin group; RR 4.12; 95% CI 0.71 to 23.76) or thromboembolic episodes (2 trials; 4/91 (4.4%) in the tranexamic acid group versus 2/87 (2.3%) in the aprotinin group; RR 1.97; 95% CI 0.37 to 10.37) between the tranexamic acid and aprotinin groups. The remaining outcomes in the above comparisons and the remaining comparisons included only only trial under the primary outcome or the outcome was not reported at all in the trials. There were no significant differences in the mortality, primary graft non-function, graft failure, retransplantation, thromboembolic episodes, or serious adverse events in any of these comparisons. However, the confidence intervals were wide, and it is not possible to reach any conclusion on the safety of the interventions. None of the trials reported the quality of life in patients.Secondary outcomes were reported in at least two trials for the following comparisons - aprotinin versus control, tranexamic acid versus control, rFVIIa versus control, thromboelastography versus control, and tranexamic acid versus aprotinin. There was significantly lower allogeneic blood transfusion requirements in the aprotinin group than the control group (8 trials; 185 patients in aprotinin group and 190 patients in control group; SMD -0.61; 95% CI -0.82 to -0.40). There were no significant differences in the allogeneic blood transfusion requirements between the tranexamic acid and control groups (4 trials; 93 patients in tranexamic acid group and 66 patients in control group; SMD -0.27; 95% CI -0.59 to 0.06); rFVIIa and control groups (2 trials; 141 patients in rFVIIa group and 80 patients in control group; SMD -0.05; 95% CI -0.32 to 0.23); thromboelastography and control groups (2 trials; 31 patients in thromboelastography group and 31 patients in control group; SMD -0.73; 95% CI -1.69 to 0.24); or between the tranexamic acid and aprotinin groups (3 trials; 101 patients in tranexamic acid group and 97 patients in aprotinin group; SMD -0.09; 95% CI -0.36 to 0.19). The remaining outcomes in the above comparisons and the remaining comparisons included only only trial under the primary outcome or the outcome was not reported at all in the trials. There were no significant differences in the blood loss, transfusion requirements, hospital stay, or intensive care unit stay in most of the comparisons.

AUTHORS' CONCLUSIONS

Aprotinin, recombinant factor VIIa, and thromboelastography groups may potentially reduce blood loss and transfusion requirements. However, risks of systematic errors (bias) and risks of random errors (play of chance) hamper the confidence in this conclusion. We need further well-designed randomised trials with low risk of systematic error and low risk of random errors before these interventions can be supported or refuted.

Optimizing cost-effectiveness in perioperative care for liver transplantation: a model for low- to medium-income countries

Although liver transplantation (LT) is a highly effective treatment, it has been considered too costly for publicly funded health systems in many countries with low to medium average incomes. However, with economic growth and improving results, some governments are reconsidering this position. Cost-effectiveness data for LT are limited, especially in perioperative care, and the techniques and costs vary widely between centers without overt differences in outcomes. Anesthesiologists working in new programs find it difficult to determine which modalities are essential, which are needed only in exceptional circumstances, and which may be omitted without effects on outcomes. We investigated key elements of preoperative evaluations, intraoperative management, and early postoperative care that might significantly affect costs in order to develop a best-value approach for new programs in resource-limited health systems. We identified all modalities of care commonly used in anesthesia and perioperative care for adult LT along with their costs. Those considered to be universally accepted as minimum requirements for safe care were excluded from the analysis, and so were those considered to be safe and low-cost, even when evidence of efficacy was lacking. The remaining items were, therefore, those with uncertain or context-restricted value and significant costs. A systematic review of the published evidence, practice surveys, and institutional guidelines was performed, and the evidence was graded and summarized. With respect to costs and benefits, each modality was then cited as strongly recommended, recommended or optional, or no recommendation was made because of insufficient evidence. Sixteen modalities, which included preoperative cardiovascular imaging, venovenous bypass, pulmonary artery catheterization, high-flow fluid warming devices, drug therapies for hemostasis, albumin, cell salvage, anesthetic drugs, personnel (staffing) requirements, and early extubation, were assessed. Only high-flow fluid warming was strongly recommended. The recommended modalities included preoperative echocardiography, cell salvage, tranexamic acid and early extubation. Six others were rated optional, and there was insufficient evidence for 5 modalities. We conclude that some costly techniques and treatments can be omitted without adverse effects on outcomes.

[The "Seville" Consensus Document on Alternatives to Allogenic Blood Transfusion. Sociedades españolas de Anestesiología (SEDAR), Medicina Intensiva (SEMICYUC), Hematología y Hemoterapia (AEHH), Transfusión sanguínea (SETS) Trombosis y Hemostasia (SETH)]

The Consensus Document on Alternatives to Allogenic Blood Transfusion (AABT) has been drawn up by a panel of experts from 5 scientific societies. The Spanish Societies of Anesthesiology (SEDAR), Critical Care Medicine and Coronary Units (SEMICYUC), Hematology and Hemotherapy (AEHH), Blood Transfusion (SETS) and Thrombosis and Hemostasis (SETH) have sponsored and participated in this Consensus Document. Alternatives to blood transfusion have been divided into pharmacological and non-pharmacological, with 4 modules and 12 topics. The main objective variable was the reduction of allogenic blood transfusions and/or the number of transfused patients. The extent to which this objective was achieved by each AABT was evaluated using the Delphi method, which classifies the grade of recommendation from A (supported by controlled studies) to E (non-controlled studies and expert opinion). The experts concluded that most of the indications for AABT were based on middle or low grades of recommendation, "C", "D", or "E", thus indicating the need for further controlled studies.

Aprotinin versus tranexamic acid during liver transplantation: impact on blood product requirements and survival

BACKGROUND

Historically, orthotopic liver transplantation (OLT) has been associated with major blood loss and the need for blood product transfusions. Activation of the fibrinolytic system can contribute significantly to bleeding. Prophylactic administration of antifibrinolytic agents was found to reduce blood loss.

METHODS

The efficacy of two antifibrinolytic compounds--aprotinin (AP) and tranexamic acid (TA)--was compared in OLT. Four hundred consecutive OLTs were studied: 300 patients received AP and 100 received TA. Multivariate logistic regression analysis was used to identify independent predictors of intraoperative transfusion requirement and 1-year patient mortality.

RESULTS

There was no intergroup difference in intraoperative blood loss (1082±1056 vs. 1007±790 mL), red blood cell transfusion per patient (0.5±1.4 vs. 0.5±1.0), final hemoglobin (Hb) concentration (93±20 g/L vs. 95±22 g/L), the percentage of OLT cases requiring no blood product administration (80% vs. 82%), and 1-year survival (85.1% vs. 87.4%). Serum creatinine concentrations were also the same (116±55 vs. 119±36 μmol/L) 1 year after surgery. Two variables, starting Hb and phlebotomy, correlated with the two primary outcome measures (transfusion and 1-year survival).

CONCLUSIONS

In our experience, administration of AP was not superior to TA with regards to blood loss and blood product transfusion requirement during OLT. In addition, we found no difference between the groups in the 1-year survival rate and renal function. Furthermore, we suggest that starting Hb concentration should be considered when prioritizing patients on the waiting list and planning perioperative care for OLT recipients.

Antifibrinolytics in liver surgery

Hyperfibrinolysis, a known complication of liver surgery and orthotopic liver transplantation (OLT), plays a significant role in blood loss. This fact justifies the use of antifibrinolytic drugs during these procedures. Two groups of drug namely lysine analogues [epsilon aminocaproic acid (EACA) and tranexamic acid (TA)] and serine-protease-inhibitors (aprotinin) are frequently used for this purpose. But uniform data or guidelines on the type of antifibrinolytic drugs to be used, their indications and correct dose, is still insufficient. Antifibrinolytics behave like a double-edged sword. On one hand, there are benefits of less transfusion requirements but on the other hand there is potential complication like thromboembolism, which has been reported in several studies. We performed a systematic search in PubMed and Cochrane Library, and we included studies wherein antifibrinolytic drugs (EACA, TA, or aprotinin) were compared with each other or with controls/placebo. We analysed factors like intraoperative red blood cell and fresh frozen plasma requirements, the perioperative incidence of hepatic artery thrombosis, venous thromboembolic events and mortality. Among the three drugs, EACA is least studied. Use of extensively studied drug like aprotinin has been restricted because of its side effects. Haemostatic effect of aprotinin and tranexamic acid has been comparable. However, proper patient selection and individualized treatment for each of them is required. Purpose of this review is to study various clinical trials on antifibrinolytic drugs and address the related issues like benefits claimed and associated potential complications.

Effect of antifibrinolytic drugs on transfusion requirement and blood loss during orthotopic liver transplantation: Results from a single center

BACKGROUND

During orthotopic liver transplantation (OLT), activation of the fibrinolytic system can contribute significantly to perioperative bleeding. Prophylactic administration of antifibrinolytic agents has been shown to reduce blood loss and the need for allogenic transfusion.

OBJECTIVE

To study the effect of antifibrinolytics on requirement of blood components, blood loss and operative time during OLT in patients with end stage liver disease, reporting to a single centre.

MATERIALS AND METHODS

Consecutive patients who underwent OLT at this centre during the period February 2003-October 2007 were the subjects of this study. Based on the individual anesthesiologist's preference, patients were assigned to receive either two million units of aprotinin (AP) as a bolus followed by 5,00,000 units/hour or 10 mg/kg tranexamic acid (TA) as a bolus followed by 10 mg/kg every six to eight hours, administered from the induction till the end of the surgery. Transfusion policy was standardized in all patients. Intraoperative red cell salvage was done wherever possible. The effect of these two antifibrinolytic drugs on transfusion requirement was evaluated as a whole and in a sub group of patients from each treatment group and compared with a concurrent control group that did not receive antifibrinolytic drugs.

RESULTS

Fifty patients (40 M / 10 F, 44 adults, 6 pediatric patients) underwent OLT in the study period. Fourteen patients were given AP, 25 patients were given TA and 11 patients did not receive any of the agents(control group). The median volume of total blood components transfused in antifibrinolytic group (n = 39) was 4540 ml(0-19,200ml), blood loss 5 l(0.7-35l) and operative time 9h (4.5-17h) and that of control group(n = 11) was 5700 ml(0-15,500ml), 10 l(0.6-25 l) and 9h (6.4-15.8h) respectively. The median volume of blood transfusions, blood loss and operative time was lesser in AP group(n = 14) than that of TA group(n = 25).

CONCLUSION

There is definite decrease in transfusion requirement, blood loss and operative time in the patients who received antifibrinolytic drugs than that of patients who did not receive. Because of the small sample size, comparisons carried between different groups did not show statistical significance. Prophylactic use of antifibrinolytics during OLT, possibly helps in blood conservation.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery, and previous reviews have found them to be effective in reducing blood loss, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2010.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. This version of the review includes a sensitivity analysis excluding trials authored by Prof. Joachim Boldt.

MAIN RESULTS

This review summarises data from 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008).

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery, and previous reviews have found them to be effective in reducing blood loss, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2010.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

This review summarises data from 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008).

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

Hyperfibrinolysis in liver disease

The incidence of hyperfibrinolysis in patients with cirrhosis is still debated. The reasons for this uncertainty probably lie in the lack of appropriate laboratory tests for its evaluation. There is a relative consensus, however, that hyperfibrinolysis can complicate the clinical course of liver cirrhosis, especially in cases of moderate to severe liver failure. Hyperfibrinolysis correlates positively with the severity of underlying liver disease, and low-grade systemic fibrinolysis is found in 30% to 46% of patients who have end-stage liver disease. Accelerated intravascular coagulation with secondary hyperfibrinolysis has been reported in patients who have liver failure. Hyperfibrinolysis may delay primary hemostasis, thereby aggravating variceal bleeding and facilitating recurrence.

Anesthetic management of hepatic transplantation

PURPOSE OF REVIEW

The present review describes new trends and ongoing controversies in the anesthetic care of liver transplant recipients.

RECENT FINDINGS

Recent studies have improved our knowledge of conditions increasing perioperative risk, such as portopulmonary hypertension and renal failure. Improved surgical and anesthetic management has reduced intraoperative blood loss, as more studies identify an independent association between blood transfusion and poor outcome. New concepts in the coagulopathy of liver failure are emerging, with clear implications for clinical practice, including greater awareness of the risks of intraoperative thromboembolism. Less invasive intraoperative hemodynamic monitoring has been advocated, as has wider use of transoesophageal echocardiography. Early extubation is becoming more routinized.

SUMMARY

Anesthetic management still varies widely between liver transplant centers with little data to indicate best practice. Future research should focus on fluid replacement, prevention and treatment of coagulopathy, care of the acutely ill patient and the safety and benefits of early extubation.