Detrimental effect of aprotinin ban on amount of blood loss during liver transplantation: single-center experience

Intraoperative transfusion management, antifibrinolytic therapy, coagulation monitoring and the impact on short-term outcomes after liver transplantation-A systematic review of the literature and expert panel recommendations

BACKGROUND

Liver transplantation (LT) is frequently complicated by coagulopathy associated with end-stage liver disease (ESLD), that is, often multifactorial.

OBJECTIVES

The objective of this systematic review was to identify evidence based intraoperative transfusion and coagulation management strategies that improve immediate and short-term outcomes after LT.

METHODS

PRISMA-guidelines and GRADE-approach were followed. Three subquestions were formulated. (Q); Q1: transfusion management; Q2: antifibrinolytic therapy; and Q3: coagulation monitoring.

RESULTS

Sixteen studies were included for Q1, six for Q2, and 10 for Q3. Q1: PRBC and platelet transfusions were associated with higher mortality. The use of prothrombin complex concentrate (PCC) and fibrinogen concentrate (FC) were not associated with reductions in intraoperative transfusion or increased thrombotic events. The use of cell salvage was not associated with hepatocellular carcinoma (HCC) recurrence or mortality. Cell salvage and transfusion education significantly decreased blood product transfusions. Q2: Epsilon-aminocaproic acid (EACA) and tranexamic acid (TXA) were not associated with decreased blood product transfusion, improvements in patient or graft survival, or increases in thrombotic events. Q3: Viscoelastic testing (VET) was associated with decreased allogeneic blood product transfusion compared to conventional coagulation tests (CCT) and is likely to be cost-effective. Coagulation management guided by VET may be associated with increases in FC and PCC use.

CONCLUSION

Q1: A specific blood product transfusion practice is not recommended (QOE; low | Recommendation; weak). Cell salvage and educational interventions are recommended (QOE: low | Grade of Recommendation: moderate). Q2: The routine use of antifibrinolytics is not recommended (QOE; low | Recommendation; weak). Q3: The use of VET is recommended (QOE; low-moderate | Recommendation; strong).

The System of Blood Coagulation in Normal and in Liver Transplantation (Review)

The review dwells on the problem of hemostatic disorders in patients undergoing liver transplantation and their correction in the perioperative period. The physiology of the hemostatic system, disorders of the blood coagulation system in patients at various stages of liver transplantation, correction of hemostatic disorders during and after orthotopic liver transplantation are discussed. Liver transplantation is performed in patients with liver diseases in the terminal stage of liver failure. At the same time, changes in the hemostatic system of these patients pose a significant risk of developing bleeding and/or thrombosis during and after liver transplantation. The hypothesis is suggested that the personalized correction of hemostasis disorder in liver transplantation should be based on considerating the nosological forms of the liver damage, mechanisms of development of recipient’s hemostatic disorders, and the stage of the surgery.

A systematic review and meta-analysis of the use of antifibrinolytic agents in total hip arthroplasty

BACKGROUND

Antifibrinolytic agents such as tranexamic acid (TXA), epsilon aminocaproic acid (EACA), and aprotinin are widely used to reduce bleeding and the need for transfusion in cardiac, orthopaedic, and hepatic surgery. We aimed to assess the efficacy and safety of antifibrinolytic agents in total hip arthroplasty (THA).

METHODS

A systematic literature search was performed using MEDLINE, PubMed, EMBASE, and Cochrane databases, as well as the reference lists of relevant articles. Only randomised controlled trials were eligible for this study. The weighted mean difference in blood loss, number of transfusions per patient, and the summary risk ratio of transfusion requirements and deep-vein thrombosis (DVT) were calculated in the antifibrinolytic agents-treated and control groups.

RESULTS

A total of 28 randomised controlled trials involving 2,131 patients were included. Patients receiving antifibrinolytic agents had a reduced total blood loss by a mean of 389.14 ml (95% CI, -483.05 to -295.23), and the number of blood transfusions per patient by 0.65 units (95% CI, -1.19 to -0.12). Antifibrinolytic agents led to a significant reduction in transfusion requirements (RR 0.55; 95% CI, 0.43 to 0.70) and no increase in the risk of DVT (RR 0.85; 95% CI, 0.51 to 1.42).

CONCLUSIONS

Our meta-analysis demonstrated that antifibrinolytic agents significantly reduce blood loss and blood transfusion requirements while not increasing the risk of DVT in patients undergoing total hip arthroplasty.

Massive haemorrhage in liver transplantation: Consequences, prediction and management

From its inception the success of liver transplantation has been associated with massive blood loss. Massive transfusion is classically defined as > 10 units of red blood cells within 24 h, but describing transfusion rates over a shorter period of time may reduce the potential for survival bias. Both massive haemorrhage and transfusion are associated with increased risk of mortality and morbidity (need for dialysis/surgical site infection) following liver transplantation although causality is difficult to prove due to the observational design of most trials. The blood loss associated with liver transplantation is multifactorial. Portal hypertension secondary to cirrhosis results in extensive collateral circulation, which can bleed during hepatectomy particular if portal pressures are increased. Avoiding volume loading and maintenance of a low central venous pressure together with the use of vasopressors have been shown to reduce blood loss and transfusion during liver transplantation, but may increase the risk of renal impairment post-operatively. Coagulation defects may be present pre-transplant, but haemostasis is often re-balanced due to a deficit in both pro- and anti-coagulation factors. Further derangement of haemostasis may develop in the anhepatic and neohepatic phases due to absent hepatic metabolic function, hyperfibrinolysis and platelet sequestration in the donor liver. Point-of-care tests of coagulation such as the viscoelastic tests rotation thromboelastometry/thromboelastometry allow and more accurate and rapid assessment of these derangements in coagulation and guide the use of factor replacement and antifibrinolytics. Transfusion protocols guided by these tests have been shown to reduce transfusion rates compared with conventional coagulation tests, but have not shown improvements in mortality or morbidity. Pre-operative factors associated with massive transfusion include previous surgery, re-do transplantation, the aetiology and severity of liver disease. Intra-operatively the use of piggy-back technique and avoiding veno-veno bypass has been shown to reduced blood loss.

Hemostasis in liver transplantation: Pathophysiology, monitoring, and treatment

Recent findings in the pathophysiology and monitoring of hemostasis in patients with end stage liver disease have major impact on coagulation management during liver transplantation. There is increasing evidence, that the changes in both coagulation factors and platelet count regularly observed in patients with liver cirrhosis cannot be interpreted as a reliable indicator of diffuse bleeding risk. Instead, a differentiated view on hemostasis has led to the concept of a rebalanced coagulation system: While it is important to recognize that procoagulant factors are reduced in liver cirrhosis, it is also evident that synthesis of anticoagulant factors and fibrinolytic proteins produced in the liver is also diminished. Similarly, the decreased platelet count may be counterbalanced by increased platelet aggregability caused by highly active von Willebrand multimeres. The coagulation system is therefor stated to be rebalanced. While under normal "unstressed" conditions diffuse bleeding is rarely observed, however both diffuse bleeding or thrombus formation may occur when compensation mechanisms are exhausted. While most patients presenting for liver transplantation have severe cirrhosis, liver function and thus production of pro- and anticoagulant factors can be preserved especially in cholestatic liver disease. During liver transplantation, profound changes in the hemostasis system can occur. Surgical bleeding can lead to diffuse bleeding as coagulation factors and platelets are already reduced. Ischemia and tissue trauma can lead to alterations of hemostasis comparable to trauma induced coagulopathy. A further common disturbance often starting with the reperfusion of the transplanted organ is hyperfibrinolysis which can eventually precipitate complete consumption of fibrinogen and an endogenous heparinization by glycocalyx shedding. Moreover, thrombotic events in liver transplantations are not uncommon and contribute to increased mortality. Besides conventional laboratory methods, bed-side monitoring of hemostasis (e.g., thrombelastography, thrombelastometry) is often used during liver transplantation to rapidly diagnose decreases in fibrinogen and platelet count as well as hyperfibrinolysis and to guide treatment with blood products, factor concentrates, and antifibrinolytics. There is also evidence which suggests when algorithms based on bed-side hemostasis monitoring are used a reduction of blood loss, blood product use, and eventual mortality are possible. Notably, the bed-side monitoring of anticoagulant pathways and the thrombotic risk is not possible at time and thus a cautious and restrictive use of blood products is recommended.

Adjunct agents for bleeding

PURPOSE OF REVIEW

This review provides a summary of the most recent clinical trials evaluating the hemostatic agents for the treatment of coagulopathy associated with critical bleeding. In particular, antifibrinolytic agents (i.e., aprotinin, tranexamic and ε-aminocaproic acids), desmopressin, recombinant activated factor VII, fibrinogen and prothrombin complex concentrates are evaluated.

RECENT FINDINGS

Among the various therapeutic options available, tranexamic acid is emerging as the most promising. Indeed, a recent randomized trial has shown a benefit survival of the early administration of tranexamic acid in patients with trauma-induced coagulopathy.

SUMMARY

Although preliminary data document a potential therapeutic role for prohemostatic pharmacologic approaches, further evidence arising from randomized controlled trials is needed to assess the safety and efficacy of such agents in the setting of critical bleeding.

Use of aprotinin to reduce blood loss and transfusion in major orthopedic surgery: a meta-analysis

BACKGROUD

Conflicting reports have been published regarding the effectiveness and safety of aprotinin in reducing blood loss and transfusion in patients undergoing orthopedic surgery. We performed a meta-analysis to evaluate the effectiveness and safety of aprotinin in reducing blood loss and transfusion in major orthopedic surgery.

MATERIALS AND METHODS

MEDLINE, PubMed, EMBASE and Cochrane databases were searched for relevant studies. Only randomized controlled trials were eligible for this study. The weighted mean difference in blood loss, and number of transfusions per patient and the summary risk ratio of transfusion requirements, and deep-vein thrombosis (DVT) were calculated in the aprotinin-treated group and the control group.

RESULTS

Eighteen randomized controlled trials involving 1276 patients were included. The use of aprotinin reduced total blood loss by a mean of 498.88 ml (95% confidence interval [CI]; -735.03 to -262.72), intra-operative blood loss by a mean of 246.11 ml (95% CI; -352.11 to -140.11), post-operative blood loss by a mean of 169.11 ml (95% CI; -234.06 to -105.55), the number of blood transfusions per patient by 0.93 units (95% CI; -1.36 to -0.51). Aprotinin led to a signficant reduction in transfusion requirements (RR 0.59; 95% CI; 0.51 to 0.69) and no increase in the risk of DVT (RR 0.58; 95% CI; 0.38 to 1.08).

CONCLUSION

The meta-analysis shows that aprotinin could significantly reduce blood loss and blood transfusion requirements in patients undergoing orthopedic surgery, and it did not appear to increase the risk of DVT.

No increase in blood transfusions during liver transplantation since the withdrawal of aprotinin

The aims of this study were to determine whether the withdrawal of aprotinin (APRO) led to an increased bleeding risk in patients undergoing orthotopic liver transplantation (OLT). A retrospective analysis compared consecutive patients undergoing OLT and treated with aprotinin (APRO group; n = 100) with a group in which aprotinin was not used (no-APRO group; n = 100). Propensity score matching was then performed for each group to identify 2 matched cohorts. Patients were matched by their primary diagnoses and Model for End-Stage Liver Disease scores. This resulted in 2 matched cohorts with 55 patients in each group. None of the patients in the APRO group had significant fibrinolysis. In the no-APRO group, 23.6% of the patients developed fibrinolysis (P < 0.003). Tranexamic acid was used in 61.5% of the patients (n = 8) in the no-APRO group in whom lysis was present, and this resolved the fibrinolysis in all but 1 of these patients. There were no differences in red blood cell, fresh frozen plasma, platelet concentrate, or cryoprecipitate transfusions between the 2 groups. In conclusion, we have shown a significant increase in the prevalence of fibrinolysis during OLT since the withdrawal of APRO. However, there has been no increase in transfusion requirements.