The relation of preoperative coagulation findings to diagnosis, blood usage, and survival in adult liver transplantation

Bloodless living donor liver transplantation: Risk factors, outcomes, and diagnostic predictors

Massive bleeding is often unavoidable during liver transplantation (LT). However, blood transfusions are associated with risks and should be avoided whenever possible. This study compares preoperative factors and outcomes between non-transfusion and transfusion groups to identify variables that could be used to predict bloodless surgery in living donor liver transplantation (LDLT) patients.We conducted a retrospective study of 87 LDLT patients. The group of patients who did not require packed red blood cell (PRBC) transfusion (non-PRBC group, n = 44) was compared with those who did (PRBC group, n = 43). We compared risk factors, fluid management, and outcomes between the groups and identified variables for prediction of transfusion during LDLT.Compared with the PRBC group, the non-PRBC group had a lower model for end-stage liver disease (MELD) score (8.1 ± 1.1 vs 18.2 ± 8.8), international normalized ratio (INR) (1.16 ± 0.1 vs 1.80 ± 0.94), and partial thromboplastin time (PTT) (37.1 ± 6.3 vs 54.1 ± 24.0), but higher hemoglobin (Hb) (13.6 ± 1.6 vs 11.5 ± 2.2) and hematocrit (HCT) (39.1 ± 4.4 vs 32.6 ± 6.0). The non-PRBC group were more likely to receive colloid and albumin but had shorter intensive care unit (ICU) and hospital length of stay. The area under the receiver operative characteristic (ROC) curve of the MELD score was the highest (91%) using a cutoff value of 10.5.Patients without PRBC transfusion during LDLT were in better condition preoperatively and had better outcomes. The MELD score is a significant predictor for PRBC transfusion.

Postoperative Liver Failure

Technical innovations in surgical techniques, anaesthesia, critical care and a spatial understanding of the intra-hepatic anatomy of the liver, have led to an increasing number of liver resections being performed all over the world. However, the number of complications directly attributed to the procedure and leading to inadequate or poor hepatic functional status in the postoperative period remains a matter of concern. There has always been a problem of arriving at a consensus in the definition of the term: postoperative liver failure (PLF). The burgeoning rate of living donor liver transplants, with lives of perfectly healthy donors involved, has mandated a consensual definition, uniform diagnosis and protocol for management of PLF. The absence of a uniform definition has led to poor comparison among various trials. PLF remains a dreaded complication in resection of the liver, with a reported incidence of up to 8 % [1], and mortality rates of up to 30–70 % have been quoted [2]. Several studies have quoted a lower incidence of PLF in eastern countries, but when it occurs the mortality is as high as in the West [3].

Subtotal hepatectomy and whole graft auxiliary transplantation for acetaminophen-associated acute liver failure

BACKGROUND

An acetominophen overdose (AOD) is the leading cause of acute liver failure (ALF) in the UK and USA. For patients who meet the King's College Hospital criteria, (mortality risk > 85%), an emergency orthotopic liver transplantation (OLT) is conventionally performed with subsequent life-long immunosuppression. A new technique was developed in 1998 for AOD-induced ALF where a subtotal hepatectomy (right hepatic trisectionectomy) and whole graft auxiliary liver transplant (WGALT) was performed with complete withdrawal of immunosupression during the first year post-operatively.

RESULTS

During 1998-2010, 68 patients were listed for an emergency transplantation for AOD ALF at our institution: 28 died waiting, 16 underwent OLT and 24 a subtotal hepatectomy with WGALT. Eight OLT (50%) and 16 WGALT remain alive (67%); actuarial survival at 5 years OLT 50%, WGALT 63%, P = 0.37. All patients who had successful WGALT are off immunosuppression. Poor prognostic factors in the WGALT group included higher donor age (40.4 versus 53.9, P = 0.043), requirements for a blood transfusion (4.3 versus 7.6, P = 0.0043) and recipient weight (63.1 versus 54 kg, P = 0.036).

CONCLUSION

Although OLT remains standard practice for AOD-induced ALF, life-long immunosuppression is required. A favourable survival rate using a subtotal hepatectomy and WGALT has been demonstrated, and importantly, all successful patients have undergone complete immunosuppression withdrawal. This technique is advocated for patients who have acetominophen hepatotoxicity requiring liver transplantation.

Thrombelastography (TEG®): practical considerations on its clinical use in trauma resuscitation

Background

Thrombelastography is a laboratorial test that measures viscoelastic changes of the entire clotting process. There is growing interest in its clinical use in trauma resuscitation, particularly for managing acute coagulopathy of trauma and assisting decision making concerning transfusion. This review focuses on the clinical use of thrombelastography in trauma, with practical points to consider on its use in civilian and military settings.

Methods

A search in the literature using the terms “thrombelastography AND trauma” was performed in PUBMED database. We focused the review on the main clinical aspects of this viscoelastic method in diagnosing and treating patients with acute coagulopathy of trauma during initial resuscitation.

Results

Thrombelastography is not a substitute for conventional laboratorial tests such as INR and aPTT but offers additional information and may guide blood transfusion. Thrombelastography can be used as a point of care test but requires multiple daily calibrations, should be performed by trained personnel and its technique requires standardization. While useful partial results may be available in minutes, the whole test may take as long as other conventional tests. The most important data provided by thrombelastography are clot strength and fibrinolysis. Clot strength measure can establish whether the bleeding is due to coagulopathy or not, and is the key information in thrombelastography-based transfusion algorithms. Thrombelastography is among the few tests that diagnose and quantify fibrinolysis and thus guide the use of anti-fibrinolytic drugs and blood products such as cryoprecipitate and fibrinogen concentrate. It may also diagnose platelet dysfunction and hypercoagulability and potentially prevent inappropriate transfusions of hemostatic blood products to non-coagulopathic patients.

Conclusions

Thrombelastography has characteristics of an ideal coagulation test for use in early trauma resuscitation. It has limitations, but may prove useful as an additional test. Future studies should evaluate its potential to guide blood transfusion and the understanding of the mechanisms of trauma coagulopathy.

Preoperative factors as predictors of blood product transfusion requirements in orthotopic liver transplantation

CONTEXT

Intraoperative transfusion can affect the chance of graft survival in liver transplantation, a complicated operation with massive blood loss. Verification of factors that are predictive of intraoperative blood loss and transfusion increases the quality of anesthesia management.

OBJECTIVE

To assess use of blood and blood products between 2002 and 2008 and to evaluate factors associated with blood loss and requirement for blood products in adult patients undergoing orthotopic liver transplantation via piggyback technique.

DESIGN

Medical charts and anesthesia records from 261 eligible adult recipients of an orthotopic liver transplant between March 2002 and May 2008 were reviewed.

SETTING

Shiraz Liver Transplantation Center, the only active liver transplantation center in Iran.

MAIN OUTCOME MEASURES

Potential influencing factors in blood loss and transfusion, including sex, preoperative hemoglobin level, international normalized ratio, primary diagnosis, platelet count, creatinine level, Model for End-Stage Liver Disease (MELD) score, central venous pressure, and total anesthesia time, were measured and subjected to multivariable analysis.

RESULTS

Mean blood loss was 54.2 (SD, 47.9) mL/kg, the mean (SD) for amounts of blood products transfused was 25.3 (19.5) mL/kg for packed red blood cells, 2.6 (3.3) units for fresh frozen plasma, and 1.7 (3.1) units for platelets. Seven recipients (2.7%) underwent transplantation without intraoperative transfusion of red blood cells, whereas 25 patients (9.6%) received more than 10 units of red blood cells intraoperatively. Multivariable analysis showed that no preoperative factor was a predictor of blood loss or requirement for intraoperative transfusion. Transfusion of fresh frozen plasma and packed red blood cells was significantly lower in 2005, 2006, 2007, and 2008 than in 2003 to 2004 (P < .001).

Requirements for transfusion and postoperative outcomes in orthotopic liver transplantation: A meta-analysis on aprotinin

AIM: To study the effect of aprotinin used in orthotopic liver transplantation (OLT) on the intraoperative requirement for blood products and on the incidence of laparotomy for bleeding, thrombotic events and mortality.

METHODS: A systematic review of the literature in the electronic database Medline and the Clinic Trials Registry Database was performed. Literature that did not fit our study were excluded. Patients in the reviewed studies were divided into two groups; one group used aprotinin (aprotinin group) while the other did not (control group). The data in the literature that fit our requirements were recorded. Weighted mean differences (WMD) in the requirements for blood products between the aprotinin group and the control group were tested using a fixed effect model. A Z test was performed to examine their reliability; the Fleiss method of fixed effect model was used to analyze data on postoperative events, and odds ratios (ORs) were tested and merged.

RESULTS: Seven citations were examined in our study. Among them, a requirement for blood products was reported in 4 studies including 321 patients, while postoperative events were reported in 5 studies including 477 patients. The requirement for red blood cells and fresh frozen plasma in the aprotinin group was statistically lower than that in the control group (WMD = -1.80 units, 95% CI, -3.38 to -0.22; WMD = -3.99 units, 95% CI, -6.47 to -1.50, respectively). However, no significant difference was indicated in the incidence of laparotomy for bleeding, thrombotic events and mortality between the two groups. Analysis on blood loss, anaphylactic reactions and renal function was not performed in this study due to a lack of sufficient information.

CONCLUSION: Aprotinin can reduce the intraoperative requirement for blood products in OLT, and has no significant effect on the incidence of laparotomy for bleeding, thrombotic events and mortality.

Thrombelastography/thromboelastometry

The term thrombelastograph (TEG) was used to describe the trace produced from the measurement of the viscoelastic changes associated with fibrin polymerization. Recently the term rotational thromboelastometry has been applied to the output of the ROTEM instrument. Since its first description in 1948, the TEG/ROTEM has been successfully used in the near patient assessment of haemostasis. The greatest use has been the application of TEG-guided transfusion of blood components in hepatic and more widely in cardiac surgery. Recent years have seen a renewed interest in the technology with applications for both pharmaceutical monitoring and patient screening being described. The present review gives a broad overview of the developments and applications related to thrombelastography/thromboelastometry.

The management of coagulopathy and blood loss in liver surgery

Liver surgery has long been associated with massive perioperative blood loss and high rates of postsurgery morbidity and mortality. Recent advances in our knowledge of hepatic segmental anatomy have led to the evolution of liver resection, and a growing awareness of the coagulopathy present in cirrhotic patients has produced a greater understanding of the factors influencing surgical hemostasis. This review will examine the risk factors for perioperative hemorrhage in liver disease patients, and will describe current pharmacological, surgical, and radiological methods available for controlling bleeding and achieving effective hemostasis during liver resection and orthotopic liver transplantation (OLT). The potential role of recombinant factor VIIa (rFVIIa) in providing safe hemostasis during such procedures will also be explored. Today, due to careful monitoring and correction of coagulopathy, improved surgical techniques, and judicious patient selection, liver surgery is no longer a high-risk specialty with an unfavorable risk profile, but a safe and widely practiced procedure.

Coagulation: consultative hemostasis

Clinical hematologists are frequently consulted for the care of hospitalized patients with complicated coagulopathies. This chapter provides an update on the scientific and clinical advances noted in disseminated intravascular coagulation (DIC) and discusses the challenges in hemostasis consultation. In Section I, Dr. Marcel Levi reviews advances in our understanding of the pathogenic mechanisms of DIC. Novel therapeutic strategies that have been developed and evaluated in patients with DIC are discussed, as are the clinical trials performed in patients with sepsis. In Section II, Dr. Lawrence Leung provides an overview of the challenging problems in thrombosis encountered in the inpatient setting. Patients with deep vein thrombosis that is refractory to conventional anticoagulation and those with extensive mesenteric thrombosis as well as the evaluation of a positive PF4/heparin ELISA in a post-operative setting are discussed. Novel treatments for recurrent catheter thrombosis in dialysis patients is addressed as well. In Section III, Dr. Julie Hambleton reviews the hemostatic complications of solid organ transplantation. Coagulopathy associated with liver transplantation, contribution of underlying thrombophilia to graft thrombosis, drug-induced microangiopathy, and the indication for postoperative prophylaxis are emphasized. Dr. Hambleton reviews the clinical trials evaluating hemostatic agents in patients undergoing liver transplantation.

Haemostatic disorders during liver transplantation

Profound and complex coagulation disorders are encountered during liver transplantation. They include preoperative coagulation disorders related to the liver disease and haemostatic changes related to the procedure itself. They commonly lead to increased intraoperative bleeding, especially due to increased fibrinolysis, the contribution of which can be demonstrated by the relative efficacy of antifibrinolytics. Given the multifactorial nature of bleeding in liver transplantation, preoperative coagulation tests cannot predict blood loss even if some statistical relationship is occasionally found. Preoperative correction of coagulation defects has not been shown to be effective in reducing intraoperative bleeding. Throughout the procedure, a rapid and sensitive method for monitoring coagulation is necessary in order to guide the rational use of blood components and pharmacological agents. The usefulness of such a method to assist management of blood loss or blood component requirements is poorly documented and controversial.

Hemostatic profiles in 39 dogs with congenital portosystemic shunts

OBJECTIVES

To determine if there were significant changes in prothrombin time (PT), partial thromboplastin time (PTT), and fibrinogen levels in dogs with naturally occurring congenital portosystemic shunts (CPSS) and to determine if there was any association between these values, serum albumin concentration, and the ability to attenuate the shunt vessel.

STUDY DESIGN

Retrospective clinical study.

ANIMALS

Thirty-nine client-owned dogs.

METHODS

Medical records of 60 dogs with confirmed CPSS were retrospectively evaluated. Hemostatic profiles had been performed before surgery in 39 cases.

RESULTS

Dogs with CPSS had significantly higher values for PTT (P < .001) when compared with normal dogs. Of the total number of dogs, 64.1% had a PTT greater than 16 seconds (25/39). PTT was prolonged by 25% or more in 51.3% of dogs (20/39). PT tended to be higher in dogs with CPSS (P = .036), although only 7.7% (3/39) of dogs had a PT greater than 12 seconds (the maximum reference value). Dogs with CPSS had significantly lower values for albumin and fibrinogen (P < .001). Platelet numbers were within the normal range in 87.2% of cases (34/39). Of the 5 dogs with platelet numbers outside the normal range, 3 were mildly thrombocytopenic. Fibrin degradation product concentrations were not elevated in any dogs tested (N = 22). There was no significant difference in any of the measured variables between dogs with extrahepatic shunts and those with intrahepatic shunts (P > .1). For PT, PTT, albumin, and fibrinogen, there was no significant difference between dogs that underwent total, partial, or no attenuation (P > .3).

CONCLUSIONS

Dogs with CPSS have a tendency to have a prolonged PTT. There was no significant difference in hemostatic profile results between dogs with intrahepatic shunts versus extrahepatic shunts. Preoperative hemostatic profile abnormalities were not useful as predictors of ability to attenuate CPSS.

CLINICAL RELEVANCE

Prolonged PTT was not associated with bleeding tendencies in any of the dogs. Assays of individual clotting factors may help to further characterize the abnormalities present in animals with CPSS and may identify specific factor deficiencies. This might enable identification of a noninvasive diagnostic or prognostic indicator.

Tranexamic acid reduces red cell transfusion better than epsilon-aminocaproic acid or placebo in liver transplantation

We evaluated the efficacy of the prophylactic administration of epsilon-aminocaproic acid and tranexamic acid for reducing blood product requirements in orthotopic liver transplantation (OLT) in a prospective, double-blinded study performed in 132 consecutive patients. Patients were randomized to three groups and given one of three drugs prophylactically: tranexamic acid, 10 mg. kg(-1). h(-1); epsilon-aminocaproic acid, 16 mg. kg(-1). h(-1), and placebo (isotonic saline). Perioperative management was standardized. Coagulation tests, thromboelastogram, and blood requirements were recorded during OLT and in the first 24 h. There were no differences in diagnosis, Child score, or preoperative coagulation tests among groups. Administration of packed red blood cells was significantly reduced (P = 0.023) during OLT in the tranexamic acid group, but not in the epsilon-aminocaproic acid group. There were no differences in transfusion requirements after OLT. Thromboembolic events, reoperations, and mortality were similar in the three groups. Prophylactic administration of tranexamic acid, but not epsilon-aminocaproic acid, significantly reduces total packed red blood cell usage during OLT.

IMPLICATIONS

In a randomized study of 132 consecutive patients undergoing liver transplantation, we found that tranexamic acid, but not epsilon-aminocaproic acid, reduced intraoperative total packed red blood cell transfusion.

Poor prediction of blood transfusion requirements in adult liver transplantations from preoperative variables

STUDY OBJECTIVE

To assess the ability of preoperative information to predict intraoperative blood transfusion requirements in adult orthotopic liver transplantation.

DESIGN

Retrospective review.

SETTING

Liver transplantation program in a referral center.

PATIENTS

583 sequential adult patients undergoing orthotopic liver transplantation.

MEASUREMENTS

Preoperative variables with a previously demonstrated relationship to intraoperative transfusion were identified from the literature. These variables were then collected retrospectively from 583 consecutive liver transplantations. Relationships between these and intraoperative blood transfusion requirements were examined by both univariate analyses and multiple linear regression analysis.

RESULTS

Univariate analysis revealed significant associations between blood transfused and the following preoperative variables: age, gender, diagnosis, presence of grade 3 or 4 encephalopathy, pseudocholinesterase, creatinine, bilirubin, mean pulmonary artery pressure, activated partial thromboplastin time, and platelet count. Multiple linear regression analysis with correction for diagnosis identified age, creatinine, bilirubin, and pseudocholinesterase as independent predictors; for the final model r(2) = 0.22.

CONCLUSION

Preoperative variables are poor predictors of intraoperative transfusion requirements even when significant associations exist, identifying a small proportion of the variability observed. A predictive approach based on this method would be too inaccurate to be of clinical use. The majority of the variability in transfusion requirements during liver transplantation most likely results from intraoperative and donor organ factors.

Blood loss in orthotopic liver transplantation: a retrospective analysis of transfusion requirements and the effects of autotransfusion of cell saver blood in 164 consecutive patients

Liver transplantation is associated with excessive blood loss. In order to identify factors influencing blood loss and to provide a basis for a pilot study to evaluate recombinant activated factor VII as a haemostatic agent, a retrospective study was performed in 164 consecutive patients with cholestatic or noncholestatic liver disease, who underwent orthotopic liver transplantation at a single centre between 1989 and 1996. Transfusion of allogeneic and autologous (cell saver) blood was used as a measurement of blood loss. Transfusion requirements were associated with age, gender, primary disease, Child-Pugh classification, serum levels of activated partial thromboplastin time, antithrombin III, urea and creatinine, platelet number, year of transplantation, length of cold ischaemia time and autologous blood transfusion. Of these variables, Child-Pugh classification (P = 0.001), urea (P = 0.0007), year of transplantation (P = 0.002), cold ischaemia time (P = 0.01) and autologous blood transfusion (P < 0.0001) were independent predictors of transfusion requirements by multivariate analysis. Thus, blood loss and transfusion requirements depend primarily on the severity of liver disease, quality of the donor liver, experience of the transplantation team and use of autologous (cell saver) blood transfusion. These findings emphasize the need for appropriate drug therapy and a critical reappraisal of current transfusion policy.

Conjugated estrogen reduces transfusion and coagulation factor requirements in orthotopic liver transplantation

We conducted a prospective, randomized study to determine the efficacy of conjugated estrogen in reducing blood product transfusion during orthotopic liver transplantation (OLT). Patients undergoing OLT were included in the study. Only those having a reaction time of more than 30 mm or 15 min (19 -28 mm) on computed thromboelastography (CTEG) at the beginning of surgery were enrolled in the study. Patients were randomized to receive either conjugated estrogen (CE) or placebo. Every patient received a first dose of CE (100 mg i.v.) (20 mL) or placebo (20 mL of isotonic sodium chloride solution) at the beginning of the procedure and a second dose of CE (100 mg i.v.) or 20 mL of placebo (20 mL of isotonic sodium chloride solution) just after reperfusion of the new graft. The two groups were similar in age, weight, requirement for veno-veno bypass, time on veno-veno bypass, CTEG measurement, and preoperative hemoglobin and platelet values. Blood products were given in relation to hematocrit and coagulation (CTEG) variables, which were measured every hour during the surgery. The amount of transfused blood products did not differ in terms of units of cryoprecipitate, but the intraoperative requirements for red blood cells (6 +/- 3 vs 9 +/- 6 U; P = 0.05), platelets (12 +/- 8 U vs 18 +/- 10 U; P = 0.05) and fresh-frozen plasma (3 +/- 3 U vs 6 +/- 4 U; P = 0.001) was significantly less in the estrogen group than in the control group. We conclude that CE is associated with a significant decrease in use of fresh-frozen plasma, platelets, and red blood cells during OLT.

IMPLICATIONS

In this study, we prospectively investigated whether i.v. conjugated estrogen could decrease blood product transfusion during orthotopic liver transplantation. Conjugated estrogen-treated patients received less fresh-frozen plasma, red blood cells, and platelets. In this population of patients, conjugated estrogen can be a useful addition in coagulation management during orthotopic liver transplantation.

Conjugated estrogen reduces transfusion and coagulation factor requirements in orthotopic liver transplantation

We conducted a prospective, randomized study to determine the efficacy of conjugated estrogen in reducing blood product transfusion during orthotopic liver transplantation (OLT). Patients undergoing OLT were included in the study. Only those having a reaction time of more than 30 mm or 15 min (19 -28 mm) on computed thromboelastography (CTEG) at the beginning of surgery were enrolled in the study. Patients were randomized to receive either conjugated estrogen (CE) or placebo. Every patient received a first dose of CE (100 mg i.v.) (20 mL) or placebo (20 mL of isotonic sodium chloride solution) at the beginning of the procedure and a second dose of CE (100 mg i.v.) or 20 mL of placebo (20 mL of isotonic sodium chloride solution) just after reperfusion of the new graft. The two groups were similar in age, weight, requirement for veno-veno bypass, time on veno-veno bypass, CTEG measurement, and preoperative hemoglobin and platelet values. Blood products were given in relation to hematocrit and coagulation (CTEG) variables, which were measured every hour during the surgery. The amount of transfused blood products did not differ in terms of units of cryoprecipitate, but the intraoperative requirements for red blood cells (6 +/- 3 vs 9 +/- 6 U; P = 0.05), platelets (12 +/- 8 U vs 18 +/- 10 U; P = 0.05) and fresh-frozen plasma (3 +/- 3 U vs 6 +/- 4 U; P = 0.001) was significantly less in the estrogen group than in the control group. We conclude that CE is associated with a significant decrease in use of fresh-frozen plasma, platelets, and red blood cells during OLT.

IMPLICATIONS

In this study, we prospectively investigated whether i.v. conjugated estrogen could decrease blood product transfusion during orthotopic liver transplantation. Conjugated estrogen-treated patients received less fresh-frozen plasma, red blood cells, and platelets. In this population of patients, conjugated estrogen can be a useful addition in coagulation management during orthotopic liver transplantation.

Primary liver transplantation without transfusion of red blood cells

BACKGROUND

This study examines factors associated with the performance of orthotopic liver transplantation (OLT) without red blood cell (RBC) transfusion.

METHODS

Between January 1992 and December 1994, 306 primary OLTs were performed with recipients divided into two groups: group 1 patients (61 recipients, 20% of total) underwent transplantation without packed RBCs, and group 2 patients (245 recipients, 80% of cases) received a transfusion of at least 1 unit of RBCs during operation.

RESULTS

Recipients in group 1 compared with group 2 had less advanced liver disease (20% hospitalized and 48% Child's class C versus 58% hospitalized and 73% Child's class C, p < 0.01) and lower frequency of right upper quadrant surgery (13% versus 25%, p < 0.05). Group 1 recipients also had significantly higher preoperative hematocrits (38% versus 33%, p < 0.01), lower prothrombin times (15.4 versus 16.7 seconds, p < 0.001) and partial thromboplastin times (36.9 versus 42.2 seconds, p < 0.01), a greater proportion of patients transplanted by piggyback technique (87% versus 59%, p < 0.001), and shorter operative times (7.9 hours versus 9.2 hours, p < 0.001). Moreover, a greater percentage of patients underwent OLT without RBC transfusion in each successive year: 9% in 1992, 21% in 1993, and 31% in 1994 (p < 0.001). Logistic regression analysis showed the following factors to be independent predictors of OLT without RBC transfusion. Preoperative Hct, United Network of Organ Sharing status, piggyback technique, operative time, and year of transplantation.

CONCLUSIONS

OLT can be performed without transfusion of RBCs in recipients with less advanced liver disease, and surgical technique, along with increased experience by the transplant team, are important factors.

Influence of UW solution on in vitro platelet aggregability

Bleeding problems in orthotopic liver transplantation (OLT), starting immediately after reperfusion of the graft, are complicating the outcome of transplantation. Platelets may be involved in this situation, but there is still a lack of information about the influence of UW solution on platelet function. We evaluated the effect of UW solution on in vitro platelet aggregability in healthy volunteers using whole blood electrical aggregometry and concluded, that UW solution causes impaired platelet aggregability and may contribute to bleeding problems during OLT. The mechanism of impairment remains unclear, since central pathways as well as membrane receptors seem to be involved. Furthermore, our data support the necessity of extended flushing of the liver graft after reperfusion.

Intraoperative blood loss in pediatric liver transplantation: analysis of preoperative risk factors

The relative contribution of 14 preoperative risk factors to a high intraoperative blood loss was studied in 95 consecutive first pediatric orthotopic liver transplantations (OLT). Patients were distributed in two groups according to red blood cell (RBC) requirements. Wide interindividual RBC requirements were observed (median, 79 mL/kg; range, 4-586). The upper quartile of the population was defined as the high blood loss group and required 123 mL/kg or more (median, 161). On univariate analysis, the high blood loss group had a significantly higher proportion of patients with portal vein hypoplasia, intraabdominal malformations, signs of severe liver failure (encephalopathy, ascites, prolonged prothrombin time), and requiring inpatient support. Age, previous abdominal surgery, and platelet count had no prognostic value. All variables used in the univariate analysis were included in a stepwise logistic regression analysis. Only presence of portal vein hypoplasia, inpatient support, and use of a reduced-size liver graft were independently associated with a high blood loss. Adjusted odds ratios were 40.4 (95% confidence interval; 5.9-278), 5.4 (1.6-17.9), and 3.8 (0.9-15.2), respectively, highlighting the importance of portal vein hypoplasia as a risk factor for high blood loss.

Comparative effects of small and large aprotinin doses on bleeding during orthotopic liver transplantation

Large prophylactic doses of aprotinin efficiently reduce blood loss during orthotopic liver transplantation (OLT). Small doses of aprotinin are usually used to treat fibrinolysis. However, no studies have investigated the benefit of prophylactic administration of a smaller dose of aprotinin during liver transplantation. We compared two methods of aprotinin therapy on transfusion outcome in liver transplant patients in a prospective study of 199 patients undergoing OLT who were randomized to large or small prophylactic doses of aprotinin during the transplant procedure. In the large-dose group (n = 94) an initial dose of 2,000,000 kallikrein inactivation units (KIU) was followed by infusion of 500,000 KIU/h until the patient's return to the intensive care unit. In the small-dose group (n = 95), an initial dose of 500,000 KIU was followed by an infusion of 150,000 KIU/h. Outcome measurements included intraoperative transfusion requirements (packed red blood cells, fresh frozen plasma, platelets, intraoperative salvage) and postoperative hematologic values. There were no differences in transfusion requirements in the two groups of patients. Patients treated with low-dose aprotinin had slightly higher postoperative fibrinogen concentrations. Large-dose aprotinin therapy does not appear to offer additional benefit compared to low-dose aprotinin administration.

Blood loss and transfusion requirements in liver transplantation: experience with the first 75 cases

The blood loss data and transfusion requirements including blood bank, salvaged washed red cells, fresh frozen plasma and cryoprecipitate were analysed for the first 75 cases of liver transplantation performed at the Austin Hospital between June 1988 and October 1992. The mean blood loss was 8.8 litres (standard deviation 14.1) with a median value of 4.0 litres. Blood product use expressed as mean number of units (SD) was bank red blood cells 7.1 (12.7), washed red blood cells 3.9 (5.9), fresh frozen plasma 7.1 (9.1), platelets 5.1 (7.4), and cryoprecipitate 1.7 (5.1). These results demonstrate that liver transplantation can be performed without imposing excessive demands on blood transfusion services. Management should include surgical techniques to minimize bleeding and use of autologous transfusion. Use of component therapy (FFP, platelets and cryoprecipitate) should not be empirical. It should be selective on the basis of clinical bleeding assessment and guided by results of the laboratory coagulation profile and changes in thrombelastographic (TEG) parameters.

Prognostic value of the activated partial thromboplastin time after orthotopic liver transplantation. A prospective study

In this prospective study, we evaluated the predictive value of activated partial thromboplastin time on day 8 post transplantation for event-free survival in patients who had had orthotopic liver transplants; both death and retransplantation within 6 months were the events considered. In a 4-year period, 109 patients had orthotopic liver transplants in our hospital, and 104 were eligible for the study since they survived and were not given new transplants within 8 days. The activated partial thromboplastin time was significantly longer in patients who survived event-free for less than 6 months than in those with longer event-free survivals. Kaplan-Meier curves showed that patients with normal activated partial thromboplastin times were nine times more likely to survive more than 6 months without events than patients with prolonged values. The positive predictive value of activated partial thromboplastin time for event-free survival was 88% and the negative predictive value was 54%, indicating that the test is useful for predicting patient outcome. We suggest that activated partial thromboplastin time be performed on day 8 post transplantation to predict the medium-term event-free survival.

Falsely low calcium measurements after high volume plasma exchange in a patient with liver failure

A 63-year-old male with lactic acidosis secondary to fialuridine-induced liver failure underwent seven plasma exchanges while awaiting orthotopic liver transplantation. Following plasma exchange, total serum calcium concentrations measured by conventional clinical chemistry methods were significantly lower than the elemental calciums determined by atomic absorption spectroscopy (P = 0.004). The difference in calcium measured by atomic absorption and by conventional methods correlated with serum citrate concentration (R = 0.77) Following the first exchange, the serum lactic acid concentration decreased from 10.2 to 4.4 mmol/L. These results suggest that plasma exchange may aid in the removal of metabolic products such as lactic acid in patients with liver failure. However, the accumulation of unmetabolized citrate may also result in falsely low total calcium measurements in some patients who undergo plasma exchange.

Liver transplantation without the use of blood products

OBJECTIVES

To examine the techniques and the outcome of liver transplantation with maximal conservation of blood products and to analyze the potential benefits or drawbacks of blood conservation and salvage techniques.

DESIGN

Case series survey.

SETTING

Tertiary care, major university teaching hospital.

PATIENTS AND METHODS

Four patients with religious objections to blood transfusions who were selected on the basis of restrictive criteria that would lower their risk for fatal hemorrhage, including coagulopathy, a thrombosed splanchnic venous system requiring extensive reconstruction, active bleeding and associated medical complications. All patients were pretreated with erythropoietin to increase production of red blood cells. All operations were performed at the same institution, with a 36-month follow-up.

INTERVENTIONS

Orthotopic liver transplantation that used blood salvage, plateletpheresis, and autotransfusion and the withholding of the use of human blood products with the exception of albumin.

MAIN OUTCOME MEASURES

Survival and postoperative complications, with the effectiveness of erythropoietin and plateletpheresis as secondary measures.

RESULTS

All patients are alive at 36 months after orthotopic liver transplantation. One patient, a minor (13 years of age), was transfused per a state court ruling. Erythropoietin increased the production of red blood cells as shown by a mean increase in hematocrit levels of 0.08. Platelet-pheresis allowed autologous, platelet-rich plasma to be available for use after allograft reperfusion. Three major complications were resolved or corrected without sequelae. Only one patient developed postoperative hemorrhage, which was corrected surgically. The mean charge for bloodless surgery was $174,000 for the three patients with United Network for Organ Sharing (UNOS) status 3 priority for transplantation. This result was statistically significant when these patients were compared with all the patients with UNOS status 3 priority during the same period who met the same restrictive guidelines (P < .05). Only 19 of 1009 orthotopic liver transplantations performed at our institution were similar according to the UNOS status and the fulfillment of the guidelines. The mean charge for these comparison patients was $327,000, 3.8% of which was related to transfusions.

CONCLUSIONS

Orthotopic liver transplantation without the use of blood products is possible. Blood conservation techniques do not increase morbidity or mortality and can result in fewer transfusion-related, in-hospital charges.

Factors influencing blood transfusion during adult liver transplantation

From 1982 to 1990, 300 adults received liver transplants in Birmingham UK with a median intraoperative blood transfusion rate of 23.5 units for the first 50 patients falling to 8 units for the last 50. The major factors in the reduction of blood usage were the experience of the team, the use of venovenous bypass and the use of an argon beam coagulator. Univariate analysis of preoperative factors in an attempt to predict patients at risk of excessive intraoperative transfusion showed that levels of serum sodium, urea, creatinine, haemoglobin, patient weight and the presence of ascites were significantly related to the quantity of blood transfused, although stepwise discriminant analysis showed that only blood urea and platelet count had an independent association with transfusion. The final model was poorly predictive of intraoperative transfusion requirements. Technical factors rather than patient-related factors are more important in the control of intraoperative bleeding in newly established transplant programmes.

Impact of aprotinin on blood transfusion requirements in liver transplantation

A retrospective study was carried out to ascertain the blood bank provision required to support a liver transplant programme and to assess the effect of intraoperative aprotinin on blood product requirements in liver transplant recipients with cirrhosis. Sixty patients with end-stage liver disease underwent 62 consecutive orthotopic liver transplants between October 1988 and January 1991. The total and intraoperative requirements of red cells, platelets and fresh frozen plasma (FFP) were analysed for three groups of liver transplant recipients, those without cirrhosis (n = 15), those with cirrhosis (n = 25) and those with cirrhosis who received intraoperative aprotinin (n = 20). Fifteen without cirrhosis had mean total requirements of 15 units of red cells, 18 units of platelets and 16 units of FFP. Twenty patients with cirrhosis who received intraoperative aprotinin had broadly similar requirements. However, blood product requirements for 25 patients with cirrhosis were significantly greater (46 units of red cells, 41 units of platelets, 43 units of FFP, excluding the seven patients with primary biliary cirrhosis). We conclude that a liver transplant programme can be supported by a teaching hospital blood bank. The use of intraoperative aprotinin significantly reduces blood product requirements.

Administration of hepatic stimulatory substance alone or with other liver growth factors does not ameliorate acetaminophen-induced liver failure

Sixty-two beagle dogs were given three doses of acetaminophen over a period of 24 hr in a fulminant liver failure model that is 70% lethal in 72 hr. Treatment of the animals with hepatic stimulatory substance alone or in a mixture with insulin, transforming growth factor-alpha and insulin-like growth factor II had no effect on mortality. Evidence of maximum regeneration with a mitotic index 20 to 25 times resting was the same in treated and untreated animals. Similarly, the biochemical and hematological indexes of liver injury were unaffected by therapy. These studies illustrate the futility of treating fulminant liver failure with exogenous growth factors that apparently are already present in large amounts in the natural response to liver injury. The results suggest that on-going liver injury by mechanisms other than lack of growth factors is the central problem of fulminant liver failure. If so, provision of regeneration-stimulating substance is an inappropriate therapeutic strategy.

Antithrombin III supplementation during orthotopic liver transplantation in cirrhotic patients: a randomized trial

Severe intraoperative bleeding is one of the main problems during liver transplantation. Acquired hemostatic defects, namely primary or secondary hyperfibrinolysis, are considered significant pathogenetic events. Antithrombin III (ATIII), the main physiological serine protease inhibitor, has a critical role in the regulation of hemostasis. 29 patients with post necrotic cirrhosis undergoing liver transplantation were randomized to receive or not ATIII replacement therapy before the induction of anaesthesia and thereafter throughout surgery. Activation of both coagulation and fibrinolysis (increase of thrombin-antithrombin complexes, fibrin and fibrinogen degradation products) were demonstrated in both groups. Blood loss and transfusion requirements were not affected by ATIII administration.

Prognostic value of hemostatic parameters after liver transplantation

The prognostic value of hemostatic parameters after orthotopic liver transplantation was evaluated in 37 consecutive patients. Six simple hemostatic parameters (prothrombin time, activated partial thromboplastin time, thrombin time, thrombin coagulase time, plasma fibrinogen and platelet count) were obtained for each patient pre-transplantation and daily post-transplantation for at least 8 days. Using the results of these tests, the degree of hemostatic impairment was arbitrarily scored from 0 to 6. Starting from the first day post-transplantation, hemostatic parameters improved progressively, reaching plateau values on day 7 post-transplantation. On day 8 there were significant differences in the activated partial thromboplastin time, prothrombin time, and in the overall hemostatic scores between patients who survived at least 6 months and those who died. Comparing these hemostasis parameters with such liver function tests as AST, ALT and serum bilirubin, univariate analysis showed that activated partial thromboplastin time, coagulation score and AST were significant predictors of 6-month survival, but by multivariate analysis (Cox proportional hazard rate model) only the activated partial thromboplastin time was an independent predictor. Hence, a simple coagulation test is useful for predicting the survival of patients undergoing liver transplantation.