Antifibrinolytics in orthotopic liver transplantation: current status and controversies

Possible roles of platelets in liver transplantation: regeneration and cancer recurrence

When tissue injury results in breakage, platelets are not only involved in plug formation and wound sealing, but they also play an important role throughout the tissue recovery process. Specifically, platelets accumulate at the site of injury and release a large number of biologically active mediators at injury sites, which initiate or modulate damaged tissue regeneration. Moreover, extensive experimental evidence has elucidated the involvement of platelets in tumor growth and metastasis. As such, this mini-review aimed to highlight the relatively lesser known functions of platelets.

Reversal of ε-Aminocaproic Acid-Induced Massive Thromboemboli Using Tissue Plasminogen Activator During Cardiac Surgery: A Case Report

ε-Aminocaproic acid is routinely used in cardiac surgery to prevent excess bleeding. It is rarely associated with thrombotic events. This case report illustrates the formation of intracardiac thrombi leading to massive pulmonary embolism during a coronary artery bypass graft surgery, secondary to the administration of ε-aminocaproic acid as confirmed by intraoperative transesophageal echocardiogram. After a failure of resolution with high-dose heparin, tissue plasminogen activator was used to successfully reverse the patient's hypercoagulable state.

Association between viscoelastic tests-guided therapy with synthetic factor concentrates and allogenic blood transfusion in liver transplantation: a before-after study

Background

Perioperative bleeding and transfusion are important causes of morbidity and mortality in patients undergoing liver transplantation. The aim of this study is to assess whether viscoelastic tests-guided therapy with the use of synthetic factor concentrates impact transfusion rates of hemocomponents in adult patients undergoing liver transplantation.

Methods

This is an interventional before-after comparative study. Patients undergoing liver transplantation before the implementation of a protocol using thromboelastometry and synthetic factor concentrates were compared to patients after the implementation. Primary outcome was transfusion of any hemocomponents. Secondary outcomes included: transfusion of red blood cells (RBC), fresh frozen plasma (FFP), cryoprecipitate or platelets, clinical complications, length of stay and in-hospital mortality.

Results

A total of 183 patients were included in the control and 54 in the intervention phase. After propensity score matching, the proportion of patients receiving any transfusion of hemocomponents was lower in the intervention phase (37.0 vs 58.4%; OR, 0.42; 95% CI, 0.20–0.87; p = 0.019). Patients in the intervention phase received less RBC (30.2 vs 52.5%; OR, 0.21; 95% CI, 0.08–0.56; p = 0.002) and FFP (5.7 vs 27.3%; OR, 0.11; 95% CI, 0.03–0.43; p = 0.002). There was no difference regarding transfusion of cryoprecipitate and platelets, complications related to the procedure, hospital length of stay and mortality.

Conclusions

Use of a viscoelastic test-guided transfusion algorithm with the use of synthetic factor concentrates reduces the transfusion rates of allogenic blood in patients submitted to liver transplantation.

Trial registration

This trial was registered retrospectively on November 15th, 2018 – clinicaltrials.gov – Identifier: NCT03756948.

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0664-8) contains supplementary material, which is available to authorized users.

Efficacy and tolerance of early administration of tranexamic acid in patients with cirrhosis presenting with acute upper gastrointestinal bleeding: a study protocol for a multicentre, randomised, double-blind, placebo-controlled trial (the EXARHOSE study)

INTRODUCTION

The management of acute upper gastrointestinal bleeding (UGIB) is challenging in patients with cirrhosis, as it is responsible for severe complications and high mortality rates. Tranexamic acid (TXA) may help control the bleeding by counterbalancing cirrhosis-related hyperfibrinolysis. Still, there is a lack of unbiased data to conclude on its efficacy. The aim of this study is to evaluate the efficacy of TXA in the early treatment of acute UGIB in patients with cirrhosis.

METHODS AND ANALYSIS

This study is a multicentre, randomised, double-blind, placebo-controlled trial, for adult patients with cirrhosis presenting with an acute UGIB and allocated to one of two arms: TXA or placebo (saline). Physicians from emergency mobile services, emergency departments (EDs) or intensive care units (ICUs) can include patients. Besides study intervention, standard care for UGIB will be performed as recommended. Intervention will consist an intravenous infusion of 10 mL of TXA (1 g) or saline, immediately followed by three identical intravenous infusions over 8 hours each (total dose of 4 g of TXA or 40 mL of placebo over 24 hours). Main analyses will be conducted in intention to treat on every patient included, then in modified intention to treat on patients with underlying lesion of portal hypertension visualised by endoscopy. The main objective is to show efficacy of TXA until day 5 on a composite criterion (bleeding control, rebleeding episodes and mortality). Secondary objectives aim at showing the efficacy of TXA on each individual component of the main outcome measure and others at 6 weeks and later (transjugular intrahepatic portosystemic shunt procedure, cirrhosis-specific complications, length of stay in ICU and in hospital, safety and tolerance of TXA, liver transplantation). Included patients will be followed up to 1 year after inclusion.500 patients will be necessary to show a reduction in the prevalence of the primary outcome from 30% to 18% with a bilateral alpha risk of 5% and a power of 80%.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Comité de Protection des Personnes Ile-de-France 1 (CPP-IDF1). Results will be disseminated via publications in peer-review medical journals and scientific forums.

PROTOCOL VERSION

This protocol is based on the latest version, as established on 11 October 2017 and validated by the IRB CPP Ile-de-France 1.

TRIAL REGISTRATION NUMBER

NCT03023189.

Association Between Intraoperative Platelet Transfusion and Early Graft Regeneration in Living Donor Liver Transplantation

OBJECTIVE

To evaluate the association between anesthetic management before and after graft reperfusion and early graft regeneration in living donor liver transplantation (LDLT).

BACKGROUND

Sufficient graft regeneration is essential for the success of LDLT. Diverse signals start to trigger liver regeneration immediately after graft reperfusion.

METHODS

Graft volume at 14 ± 2 days after LDLT was measured in 379 consecutive recipients using computed tomography images with 3-dimensional reconstruction. The association between anesthetic variables and the degree of graft regeneration for 2 weeks was analyzed using simple and multiple linear regressions. The anesthetic variables included hemodynamics, laboratory measurements, vasoactive drugs, and blood products transfusion.

RESULTS

The degree of graft regeneration for 2 weeks was 52% in median and ranged from 5% to 123%. Platelet transfusion was identified as the sole independent anesthetic factor contributing to graft regeneration. Platelet concentrate transfusion of 1 to 6 units vs none was correlated with a 6.5% increase in graft regeneration (P = 0.012). Platelet concentrate transfusion of more than 6 units vs none was further correlated with an 18.4% increase in regeneration (P < 0.001). In the subgroup of recipients without intraoperative platelet transfusion, mean platelet count measured during the intraoperative reperfusion phase was positively associated with graft regeneration (P = 0.033).

CONCLUSIONS

Graft regeneration after LDLT increased in relation to a graded increase in the amount of transfused platelets and higher postreperfusion platelet counts during surgery. These results offer additional evidence regarding the important role of platelets in initiating liver regeneration and, furthermore, the indications for and the benefits vs risks of platelet transfusion during LDLT.

Anaesthesia for liver transplantation

Liver transplantation is a complex procedure that requires a truly multidisciplinary team approach with anaesthetic involvement from the outset in order to ensure excellent outcomes. Before a patient is placed on the waiting list for a liver transplant, a thorough evaluation is undertaken and his/her suitability for transplantation discussed in a patient selection committee meeting. The perioperative management of patients requiring transplantation can be challenging because of the systemic implications of liver disease, approaches to surgical technique and the quality of the grafts used; an increase in the use of marginal donor organs to meet the organ demand poses its own unique difficulties.

Survey of hemostasis management and transfusion in liver transplantation

OBJECTIVE

To determine the management of haemostasis and transfusion practice in the field of liver transplantation in Spain.

METHODS

A questionnaire was developed for physicians in anaesthesiology of all centres performing liver transplantation in Spain. The information required made reference to the 12 months prior to its distribution, from January 1 to December 31, 2011.

RESULTS

Data were collected from 24 centres in which liver transplantation is performed in Spain. Only 46% reported that they had protocols or practice guidelines for the management of haemostasis, and 83% of hospitals responded that they knew the percentage of transfused patients, but only 57% knew the mean transfusion. Regarding the degree of satisfaction with the management of haemostasis/coagulation, 50% said they were not satisfied. Thromboelastometry was used as an additional method of preoperative monitoring in only 8% of the centres and intra-operatively in one-third. Less than half (46%) of the centres performed preoperative correction of coagulation deficits based on conventional tests. The mean number of packed red cells used was ≤4 in 57% of centres. Consumption of fresh frozen plasma was highly variable, while 100% of centres consumed less than 4 pools of platelets per patient.

CONCLUSIONS

There is a wide variability in the management of haemostasis and transfusion practice among Spanish centres. There are no guidelines or they are not widely used. The mean use of transfused blood products remain high. There was a decrease in centres using new methods of monitoring.

Application of long-acting VLHL PAI-1 during sutureless partial nephrectomy in mice reduces bleeding

PAI-1 prevents lysis of blood clot by inhibiting the urokinase and tPA induced conversion of plasminogen to plasmin. VLHL PAI-1 protein mutant was created to extend half-life over 700 hours. The objective of this paper was to test VLHL PAI-1 effects on bleeding during partial nephrectomy in mice. All animals had a left partial nephrectomy after intravenous infusion of saline or tPA. The animals were divided into four groups. Group 1 was infused with saline and kidney was exposed to saline too; Group 2 was infused with saline and kidney was exposed to PAI-1. Group 3 was infused with tPA and kidney was exposed to saline, while Group 4 was infused with tPA and kidney was exposed to PAI-1. Preweighed gauze containing PAI-1 or saline was then applied to the kidney for 30 minutes. The gauze was afterward weighed and blood loss was measured by subtracting the preweight of gauze from the final weight. We have observed a statistically significant (P ≤ 0.05) reduction of bleeding in PAI-1-treated group in comparison to saline and tPA-treated groups. Based on these results we propose that VLHL PAI-1 can be used therapeutically in limiting the flow of blood from renal wounds.

Aminocaproic Acid (amicar) as an alternative to aprotinin (trasylol) in liver transplantation

INTRODUCTION

This study compared clinical outcomes for a large number of liver transplant patients receiving intraoperative epsilon-aminocaproic acid (EACA), aprotinin, or no antifibrinolytic agent over an 8-year period.

PATIENTS AND METHODS

Records for deceased donor liver transplants were reviewed. Data included antifibrinolytic agent, blood loss, early graft function, and postoperative complications. Study groups included low-dose aprotinin, high-dose aprotinin, EACA (25 mg/kg, 1-hour infusion), or no antifibrinolytic agent.

RESULTS

Data were included for 1170 consecutive transplants. Groups included low-dose aprotinin (n = 324 [28%]), high-dose aprotinin (n = 308 [26%]), EACA (n = 216 [18%]), or no antifibrinolytic (n = 322 [28%]). EACA had the lowest intraoperative blood loss and required the fewest transfusions of plasma. Patients receiving no agent required the most blood transfusions. Early graft loss was lowest in the EACA group, and 90-day and 1-year patient survival rates were significantly higher for the low-dose aprotinin and EACA groups according to Cox regression. Complications were similar, but there were more episodes of deep vein thrombosis in patients receiving EACA.

CONCLUSIONS

These results suggest that transitioning from aprotinin to EACA did not result in worse outcomes. In addition to decreased intraoperative blood loss, a trend toward improved graft and patient survival was seen in patients receiving EACA.

Recent advances on plasmin inhibitors for the treatment of fibrinolysis-related disorders

Growing evidence suggests that plasmin is involved in a number of physiological processes in addition to its key role in fibrin cleavage. Plasmin inhibition is critical in preventing adverse consequences arising from plasmin overactivity, e.g., blood loss that may follow cardiac surgery. Aprotinin was widely used as an antifibrinolytic drug before its discontinuation in 2008. Tranexamic acid and ε-aminocaproic acid, two small molecule plasmin inhibitors, are currently used in the clinic. Several molecules have been designed utilizing covalent, but reversible, chemistry relying on reactive cyclohexanones, nitrile warheads, and reactive aldehyde peptidomimetics. Other major classes of plasmin inhibitors include the cyclic peptidomimetics and polypeptides of the Kunitz and Kazal-type. Allosteric inhibitors of plasmin have also been designed including small molecule lysine analogs that bind to plasmin's kringle domain(s) and sulfated glycosaminoglycan mimetics that bind to plasmin's catalytic domain. Plasmin inhibitors have also been explored for resolving other disease states including cell metastasis, cell proliferation, angiogenesis, and embryo implantation. This review highlights functional and structural aspects of plasmin inhibitors with the goal of advancing their design.

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.

Hemostasis in liver disease: implications of new concepts for perioperative management

The hemostatic profile of patients with liver diseases is frequently profoundly different from that of healthy individuals. These complex alterations lead to abnormal results from routine laboratory tests, but because of the nature of these assays, they fail to accurately represent the patient's hemostatic state. Nevertheless, based on abnormal laboratory coagulation values, it has long been assumed that patients with liver disease have a natural bleeding tendency and are protected from thrombosis. This assumption is false; the average patient with liver disease is actually in a state of "rebalanced hemostasis" that can relatively easily be tipped toward both bleeding and thrombosis. The new paradigm of rebalanced hemostasis has strong implications for the clinic, which are presented in this review. There is no evidence that prophylactic transfusion of plasma helps to prevent procedure-related bleeding. In addition, the presence of independent risk factors such as poor kidney status or infections should be carefully assessed before invasive procedures. Furthermore, central venous pressure plays an important role in the risk of bleeding in patients with liver diseases, so during procedures, a restrictive infusion policy should be applied. Finally, thrombosis prophylaxis should not be withheld from patients with cirrhosis or acute liver failure, and clinicians should be alert to the possibility of thrombosis occurring in these patients.

Perioperative use of allogenic blood components in live-related donor orthotopic liver transplantation: A cross sectional study

BACKGROUND

In spite of many improvements that have reduced the blood component requirements, substantial numbers of transfusions are still needed in liver transplantation.

AIMS

The objective of the present study was to analyze the perioperative usage of allogenic blood components and predict the preoperative factors as predictors of red cell transfusion in live-related donor liver transplant recipients.

MATERIALS AND METHODS

The retrospective data on utilization of allogenic blood components were analyzed for a total of 150 liver transplant procedures. The data on utilization of blood components during surgery and till 48 hours of ICU stay was collected from the blood bank record and hospital information system (HIS).

RESULTS

Red cell concentrate was commonest blood component used in liver transplant recipient and most of the transfusion took place during surgery. During intraoperative period 92.7% (N = 139) of the cases utilized red cell components with the median number of five whereas in postoperative period only 38% (N = 57) of patients received blood with the median number of one. This study demonstrates that the preoperative hemoglobin and platelet count are the predictors of utilization of red cell concentrates during surgery. There were a total of 11 (7.3%) recipients who didn't receive allogeneic blood transfusion in any form. Utilization of blood components was negligible among organ donors.

CONCLUSION

Our study demonstrates the pattern and predictors of usage of allogeneic blood components in liver transplant recipients at a tertiary healthcare center in India.

Disruptions in the supply of medications used in transplantation: implications and management strategies for the transplant clinician

Drug shortages are a threat to patient care and public health, and the number of drugs on shortage is growing at an exponential rate. The major therapy areas affected by these shortages are oncology, anti-infective, cardiovascular and central nervous system. However, drugs utilized in the transplant patient population have not been exempt, and can have significant influence on posttransplant outcomes. The purpose of this review is to discuss the current and historical solid organ transplant-related disruptions in the supply of medications and implications on patient care and safety. Transplant centers should be armed with an implementation plan when imperative transplant-related drugs such as tacrolimus, mycophenolate, or antithymocyte globulin go on shortage. This plan should provide steps to manage the shortage, and provide effective therapeutic alternatives.

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.

Differential effects of plasma and red blood cell transfusions on acute lung injury and infection risk following liver transplantation

Patients with chronic liver disease have an increased risk of developing transfusion-related acute lung injury (TRALI) from plasma-containing blood products. Similarly, red blood cell transfusions have been associated with postoperative and nosocomial infections in surgical and critical care populations. Patients undergoing liver transplantation receive large amounts of cellular and plasma-containing blood components, but it is presently unclear which blood components are associated with these postoperative complications. A retrospective cohort study of 525 consecutive liver transplant patients revealed a perioperative TRALI rate of 1.3% (7/525, 95% confidence interval = 0.6%-2.7%), which was associated with increases in the hospital mortality rate [28.6% (2/7) versus 2.9% (15/518), P = 0.02] and the intensive care unit length of stay [2 (1-11 days) versus 0 days (0-2 days), P = 0.03]. Only high-plasma-containing blood products (plasma and platelets) were associated with the development of TRALI. Seventy-four of 525 patients (14.1%) developed a postoperative infection, and this was also associated with increased in-hospital mortality [10.8% (8/74) versus 2.0% (9/451), P < 0.01] and a prolonged length of stay. Multivariate logistic regression determined that the number of transfused red blood cell units (adjusted odds ratio = 1.08, 95% confidence interval = 1.02-1.14, P < 0.01), the presence of perioperative renal dysfunction, and reoperation were significantly associated with postoperative infection. In conclusion, patients undergoing liver transplantation have a high risk of developing postoperative complications from blood transfusion. Plasma-containing blood products were associated with the development of TRALI, whereas red blood cells were associated with the development of postoperative infections in a dose-dependent manner.

Incidental intracardiac thromboemboli during liver transplantation: incidence, risk factors, and management

Even though numerous cases of massive thromboemboli have been reported in the literature, intracardiac thromboemboli (ICTs) incidentally found during orthotopic liver transplantation (OLT) have not been examined. In this study, we retrospectively examined the incidence, risk factors, and management of incidental ICTs during OLT. After institutional review board approval, adult patients who underwent OLT between January 2004 and December 2008 at our center were reviewed. ICTs were identified and confirmed by the examination of OLT datasheets, anesthesia records, and recorded transesophageal echocardiography (TEE) clips. The clinical presentation, management, and outcomes of the patients with ICTs were reviewed. Risk factors were analyzed by multivariate logistic regression. During the study period, 426 of the 936 adult OLT patients (45.5%) underwent intraoperative TEE monitoring. Incidental ICTs were identified in 8 of these 426 patients (1.9%). Two ICTs occurred before reperfusion, and 6 ICTs occurred after reperfusion. The treatment was at the discretion of the treating physicians; however, none of the patients received an anticoagulant or thrombolytics. Multivariate analysis identified 2 independent risk factors for intraoperative incidental ICTs: the presence of symptomatic or surgically treated portal hypertension (a history of gastrointestinal bleeding, a transjugular intrahepatic portosystemic shunt procedure, or portocaval shunt surgery) before OLT and intraoperative hemodialysis (odds ratios of 4.05 and 7.29, respectively; P < 0.05 for both). In conclusion, incidental ICTs during OLT occurred at a rate of 1.9% and were associated with several preoperative and intraoperative risk factors. The use of TEE allows early identification, which may be important. Our management for incidental ICTs is described; however, no conclusions can be made about the optimal therapy.

Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of the collagen-binding region of RspB from Erysipelothrix rhusiopathiae

Liver transplant procedures require the most blood components, despite the fact that blood use in liver transplantation has declined dramatically over the last decade. Liver transplant recipients present unique challenges, not only in terms of blood supply, but also requirements for specialized blood components, serologic problems, and immunologic effects of transfusion on both the allograft and the recipient. The cause of intraoperative blood loss in liver transplantation is multifactorial, due to both technical factors and poor coagulation control. This procedure carries the risk of massive blood loss, which requires massive transfusions and is associated with postoperative infections, reduced graft survival, multi-organ dysfunction, and higher risk of mortality. Efforts to reduce intraoperative bleeding leading to limitation of blood transfusions are desirable to improve results and also to control costs.

Method of literature search:

The name of topic is typed and searched in Google search.

The name of topic is typed and searched in PubMed search. Related articles were also searched.

Some standard books in Transfusion Medicine were also referred.

The role of anti-fibrinolytics, rFVIIa and other pro-coagulants: prophylactic versus rescue?

Patients who have liver disease experience an increased risk for bleeding and resulting complications. Diseases affecting the liver can cause a deficiency of pro-coagulant factors or induce a state of increased clot breakdown. Although traditional tests of coagulation, such as prothrombin time or international normalized ratio (INR), may not accurately measure bleeding risk, many studies have assessed measures used to correct an increased INR and minimize adverse outcomes. This article discusses the use of activated factor VIIa and anti-fibrinolytic agents to treat coagulopathy in the setting of liver disease and the potential advantages and disadvantages of these alternatives, and the limitations of the current literature. This article also compares the limitations, risks, and potential benefits of prophylactic therapy to prevent bleeding before invasive procedures with rescue therapy for spontaneous and postprocedure bleeding, and describes the relative advantages and disadvantages of these two approaches.

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.

Current approach to intraoperative monitoring in liver transplantation

PURPOSE OF REVIEW

Although liver transplantation has become a standardized treatment and the only established definite therapy for end-stage liver disease it remains a unique clinical procedure. Increased understanding of the specific pathophysiological changes in end-stage liver disease and the transplantation procedure have led to the adaptation of concepts including overall monitoring of the patient and assessment of specific organ function.

RECENT FINDINGS

Major emphasis is placed on adequate monitoring during perioperative care of liver transplantation patients in order to ensure optimal hemodynamic and respiratory performance. The immediate assessment of metabolism and graft function will also serve to guide therapy according to the individual patient's needs.

SUMMARY

The evolution of monitoring during standardized liver transplantation, as well as currently recommended novel devices and concepts, are described and discussed.

A benefit-risk review of systemic haemostatic agents: part 1: in major surgery

Systemic haemostatic agents play an important role in the management of blood loss during major surgery where significant blood loss is likely and their use has increased in recent times as a consequence of demand for blood products outstripping supply and the risks associated with transfusions. Their main application is as prophylaxis to reduce bleeding in major surgery, including cardiac and orthopaedic surgery and orthotopic liver transplantation. Aprotinin has been the predominant agent used in this setting; of the other antifibrinolytic agents that have been studied, tranexamic acid is the most effective and epsilon-aminocaproic acid may also have a role. Eptacog alfa (recombinant factor VIIa) has also shown promise. Tranexamic acid, epsilon-aminocaproic acid and eptacog alfa are generally well tolerated; however, when considering the methods to reduce or prevent blood loss intra- and postoperatively, the benefits of these agents need to be weighed against the risk of adverse events. Recently, concerns have been raised about the safety of aprotinin after an association between increased renal dysfunction and mortality was shown in retrospective observational studies and an increase in all-cause mortality with aprotinin relative to tranexamic acid or epsilon-aminocaproic acid was seen after a pre-planned periodic analysis of the large BART (Blood conservation using Antifibrinolytics in a Randomized Trial) study. The latter finding resulted in the trial being halted, and aprotinin has subsequently been withdrawn from the market pending detailed analysis of efficacy and safety results from the study. Part 1 of this benefit-risk review examines the efficacy and adverse effect profiles of systemic haemostatic agents commonly used in surgery, and provides individual benefit-risk profiles that may assist clinicians in selecting appropriate pharmacological therapy in this setting.

Intraoperative pulmonary embolism and intracardiac thrombosis complicating liver transplantation: a systematic review

BACKGROUND

Pulmonary embolism (PE) and intracardiac thrombosis (ICT) are rare but potentially lethal complications during orthotopic liver transplantation (OLT).

METHODS

We aimed to review clinical and pathological correlates of PE and ICT in patients undergoing OLT. A systematic review of the literature was conducted using MEDLINE and ISI Web of Science.

RESULTS

Seventy-four cases of intraoperative PE and/or ICT were identified; PE alone in 32 patients (43%) and a combination of PE and ICT in 42 patients (57%). Most frequent clinical symptoms included systemic hypotension and concomitant rising pulmonary artery pressure, often leading to complete circulatory collapse. PE and ICT occurred in every stage of the operation and were reported equally in patients with or without the use of venovenous bypass or antifibrinolytics. A large variety of putative risk factors have been suggested in the literature, including the use of pulmonary artery catheters or certain blood products. Nineteen patients underwent urgent thrombectomy or thrombolysis. Overall mortality was 68% (50/74) and 41 patients (82%) died intraoperatively.

CONCLUSION

Mortality was significantly higher in patients with an isolated PE, compared to patients with a combination of PE and ICT (91% and 50%, respectively; P < 0.001). Intraoperative PE and ICT during OLT appear to have multiple etiologies and may occur unexpectedly at any time during the procedure.

Cardiovascular collapse due to massive pulmonary thromboembolism during orthotopic liver transplantation

Severe pulmonary thromboembolism has been occasionally reported during orthotopic liver transplantation, with fatal outcomes occurring in about 50% of cases because of low cardiac output and multiple organ failure. Perioperative alterations in coagulation, insertion of pulmonary artery and other invasive catheters, administration of antifibrinolytic agents, and repeated ischemic insults may all promote the formation of intravascular/cardiac blood clots. We present a case of intraoperative right ventricular failure associated with the presence of a large thrombus wrapped around the pulmonary artery catheter. Identification of risk factors for intraoperative pulmonary thromboembolism warrants a prophylactic medical approach including selective blood component therapy and administration of antifibrinolytics guided by bedside coagulation tests as well as noninvasive hemodynamic monitoring.

Successful intraoperative use of recombinant tissue plasminogen activator during liver transplantation complicated by massive intracardiac/pulmonary thrombosis

During orthotopic liver transplantation a patient received epsilon-aminocaproic acid and clotting factors. Shortly after hepatic artery clamping the patient developed a massive intracardiac/intravascular thrombosis that resulted in cardiac arrest. After diagnosis by transesophageal echocardiography, the patient was treated with recombinant tissue plasminogen activator through a central venous catheter advanced into the right atrium. After treatment with recombinant tissue plasminogen activator, the patient's hemodynamic status improved, permitting the liver transplant to be completed. The patient was ultimately discharged to home. We report the successful intraoperative resuscitation of a patient with acute intracardiac/intravascular thrombosis during an orthotopic liver transplantation using thrombolytic therapy.

Effects of aprotinin on plasma coagulation kinetics determined by thrombelastography: role of Factor XI

BACKGROUND

Aprotinin is commonly administered in settings involving cardiopulmonary bypass and liver transplantation to decrease peri-operative bleeding. Thrombelastography has been utilized to monitor coagulation in these settings, and aprotinin delays clot initiation, presumably by inhibiting kallikrein; however, aprotinin also inhibits Factor XI (FXI), a contact system protein. Thus, it was hypothesized that celite-activated thrombelastography coagulation kin-etics would be decreased via aprotinin-mediated FXI inhibition.

METHODS

Citrated normal plasma and prekallikrein-deficient (<1% normal activity) plasma were exposed to 0, 200, 400 or 800 kallikrein inhibitory units (KIU)/ml (n = 6 per condition). Samples were recalcified and celite-activated in a thrombelastograph, with clot initiation (R, s) determined. To confirm contact system specificity, additional prekallikrein-deficient samples with 0 or 800 KIU/ml aprotinin were activated with tissue factor (n = 4 per condition).

RESULTS

Exposure of celite-activated, normal plasma to aprotinin 0, 200, 400 or 800 KIU/ml resulted in R values of 167 +/- 14, 253 +/- 10, 293 +/- 22 and 349 +/- 21 s, respectively, which were significantly different from one another (P < 0.05). Exposure of celite-activated, prekallikrein-deficient plasma to aprotinin 0, 200, 400 or 800 KIU/ml resulted in R values of 366 +/- 15, 630 +/- 64, 698 +/- 46 and 850 +/- 47 s, respectively, which were significantly different from one another (P < 0.05). There were no significant differences in R values between tissue factor-activated, prekallikrein-deficient plasma samples with 0 or 800 KIU/ml aprotinin.

CONCLUSIONS

These data support a role for the inhibition of FXI as the mechanism for aprotinin-mediated delayed contact system clot initiation determined by thrombelastography.

Massive Transfusion Coagulopathy

Coagulopathy following massive transfusion is a consequence of post-traumatic and surgical hemorrhage. Bleeding following massive transfusion can occur due to hypothermia, dilutional coagulopathy, platelet dysfunction, fibrinolysis, or hypofibrinogenemia. Transfusion of 15 to 20 units of blood products causes dilutional thrombocytopenia, and both antiplatelet agents (eg, clopidogrel [Plavix, Sanofi, Bridgewater, NJ]) and hemostatic inhibitors (eg, low-molecular-weight heparins, pentasaccharides, and direct thrombin inhibitors) are contributing factors to bleeding. Tests for platelet dysfunction are not readily available. Excessive fibrinolysis and low fibrinogen are also causes of bleeding in these patients. Currently, however, there are several agents that have been reported to be effective for the prophylaxis of hemorrhage in surgical patients, including aprotinin for cardiac surgery, orthopedic surgery, and hepatic transplantation, and the off-label use of recombinant activated factor VII (NovoSeven, Novo Nordisk, Bagsvaerd, Denmark) as rescue therapy for life-threatening hemorrhage.

Four cases of cardiopulmonary thromboembolism during liver transplantation without the use of antifibrinolytic drugs

Orthotopic liver transplantation (OLT) is one of the most demanding surgical procedures performed. Intraoperative bleeding can be substantial and related to both surgical and nonsurgical causes. A less common but previously reported phenomenon is intraoperative cardiopulmonary thromboembolism precipitating major patient morbidity and mortality. In this paper, we present four cases of intraoperative thromboembolism during OLT. These cases were performed without the concomitant use of antifibrinolytic drugs. We performed a review and analysis of previously reported cases of intraoperative thromboembolism during OLT. Possible causes of thromboembolism, clinical management, use of thromboelastography, and the role of antifibrinolytic drugs are discussed.

The effect of aprotinin in a model of uncontrolled hemorrhagic shock

BACKGROUND

Aprotinin has been shown to promote clot formation through its antifibrinolytic activity, by inhibiting the plasmin-induced complement activation and by protecting the platelets adhesive surface receptors. It has been successfully used in cardiac and liver transplantation surgery.

OBJECTIVE

To evaluate the effect of aprotinin in a model of uncontrolled intra-abdominal bleeding as a basis for its potential use in trauma patients.

METHODS

Twenty rats were randomly divided into 2 groups. All animals were operated on and bleeding was induced by transecting 1 lobe of the liver. In the treatment group a single dose of 30,000 U/kg of aprotinin was administered 5 minutes after the injury. The animals were monitored for hemodynamic parameters, blood loss volume, and mortality rates.

RESULTS

At 120 minutes from trauma induction a significant difference in mean blood pressure was observed: 67+/-22 mm Hg in the treatment group versus 53+/-28 mm Hg in the control group (P=.04). This difference remained consistent until the end of the experiment. Treatment with aprotinin also resulted in a tendency to an increased survival rate (P=.05) and increased mean survival time: 175+/-46 minutes as compared to 123+/-48 minutes in the controls (P=.027).

CONCLUSIONS

Early administration of aprotinin resulted in temporary hemodynamic stabilization and prolonged survival in a model of uncontrolled bleeding. Further studies are needed to establish the possible use of aprotinin in the treatment of trauma patients.