Reducing transfusion requirements in liver transplantation

Factors Affecting Intraoperative Blood Transfusion Requirements during Living Donor Liver Transplantation

Background: Intraoperative blood transfusion (IOBT) during liver transplantation (LT) has negative outcomes, and it has been shown that an increasing number of these procedures may no longer require IOBT. Regarding living donor liver transplantation (LDLT), the literature on the pre-transplant predictors of IOBT is quite heterogeneous and deficient. In this study, we reviewed our experience of IOBT among a homogenous cohort of adult right-lobe LDLTs. Methods: We conducted a retrospective analysis of prospectively collected data on adult LDLT recipients between January 2018 and October 2023. Two groups were constructed (No-IOBT vs. IOBT) for the exploration of pre- and intraoperative predictors of IOBT using univariate and multivariate analyses. An ROC curve analysis was applied to identify possible cut-offs. The one-year post-LDLT overall survival was compared using the Kaplan-Meier method. A p-value < 0.05 was considered statistically significant. Results: A total of 219 adult LDLT recipients were enrolled. The No-IOBT (n = 56) patients were mostly males (p = 0.016), with higher preoperative levels of HGB (p < 0.001), fibrinogen (p = 0.005), and albumin (p = 0.007) and a lower incidence of pre-transplant upper abdominal surgery (p = 0.017), portal vein thrombosis (p = 0.04), hepatorenal syndrome (p = 0.015), and ascites (p = 0.02) than the IOBT group (n = 163). The No-IOBT group had a shorter anhepatic phase (p = 0.002) and received fewer intravenous crystalloids (p = 0.001). In the multivariate analysis, the pre-transplant HGB (p < 0.001), fibrinogen (p < 0.001), and albumin (p = 0.04) levels were independent predictors of IOBT, showing the following cut-offs in the ROC curve analysis: HGB ≤ 11.5 (AUC: 0.800, p < 0.001), fibrinogen ≤ 125 (AUC: 0.638, p = 0.0024), and albumin ≤ 3.6 (AUC: 0.663, p = 0.0002). These were significantly associated with the No-IOBT group. The one-year overall survival of the No-IOBT and IOBT groups was 100% and 83%, respectively (p = 0.007). Conclusions: IOBT during LDLT is associated with inferior outcomes. The increased need of IOBT during LT can be predicted by evaluating serum levels of hemoglobin, albumin and fibrinogen before liver transplantation.

The effect of high-volume intraoperative fluid administration on outcomes among pediatric patients undergoing living donor liver transplantation

BACKGROUND

Pediatric patients undergoing liver transplantation are particularly susceptible to complications arising from intraoperative fluid management strategies. Conventional liberal fluid administration has been challenged due to its association with increased perioperative morbidity. This study aimed to assess the impact of intraoperative high-volume fluid therapy on pediatric patients who are undergoing living donor liver transplantation (LDLT).

METHODS

Conducted at the Children's Hospital of Chongqing Medical University from March 2018 to April 2021, this retrospective study involved 90 pediatric patients divided into high-volume and non-high-volume fluid administration groups based on the 80th percentile of fluid administered. We collected the perioperative parameters and postoperative information of two groups. Multivariable logistic regression was utilized to assess the association between estimated blood loss (EBL) and high-volume FA. Kaplan-Meier survival analysis was used to compare patient survival after pediatric LDLT.

RESULTS

Patients in the high-volume FA group received a higher EBL and longer length of stay than that in the non-high-volume FA group. Multivariate logistic regression analysis indicated that hours of maintenance fluids and fresh frozen plasma were significantly associated risk factors for the occurrence of EBL during pediatric LDLT. In addition, survival analysis showed no significant differences in one-year mortality between the groups.

CONCLUSIONS

High-volume fluid administration during LDLT is linked with poorer intraoperative and postoperative outcomes among pediatric patients. These findings underscore the need for more conservative fluid management strategies in pediatric liver transplantations to enhance recovery and reduce complications.

Implication of Hypotension in the Pathogenesis of Cognitive Impairment and Brain Injury in Chronic Liver Disease

The incidence of chronic liver disease is on the rise. One of the primary causes of hospital admissions for patients with cirrhosis is hepatic encephalopathy (HE), a debilitating neurological complication. HE is defined as a reversible syndrome, yet there is growing evidence stating that, under certain conditions, HE is associated with permanent neuronal injury and irreversibility. The pathophysiology of HE primarily implicates a strong role for hyperammonemia, but it is believed other pathogenic factors are involved. The fibrotic scarring of the liver during the progression of chronic liver disease (cirrhosis) consequently leads to increased hepatic resistance and circulatory anomalies characterized by portal hypertension, hyperdynamic circulatory state and systemic hypotension. The possible repercussions of these circulatory anomalies on brain perfusion, including impaired cerebral blood flow (CBF) autoregulation, could be implicated in the development of HE and/or permanent brain injury. Furthermore, hypotensive insults incurring during gastrointestinal bleed, infection, or liver transplantation may also trigger or exacerbate brain dysfunction and cell damage. This review will focus on the role of hypotension in the onset of HE as well as in the occurrence of neuronal cell loss in cirrhosis.

Perioperative management of a severely thrombocytopenic kidney transplant recipient using thromboelastography

Perioperative transfusion of blood and blood products can be avoided or reduced with bedside real time monitoring of coagulation in patients at risk. Thromboelastography (TEG), is a point of care coagulation monitor to assess dynamic progress of clot formation. We report a case of 26 years old female patient with end-stage kidney disease (ESKD) who underwent living donor kidney transplantation at our institute. On preoperative work-up, her complete blood count revealed severe thrombocytopenia. Etiology of thrombocytopenia could not be established except past history of hemolysis, elevated liver enzymes, and low platelets syndrome in her last pregnancy. Perioperative transfusion of blood and blood products was guided with TEG and transplant was conducted successfully without any transfusion. In conclusion, severe thrombocytopenia in patients with ESKD enhances the risk of perioperative bleeding and related complications in already compromised coagulation system. Kidney transplant without pre-emptive transfusion could be possible with perioperative use of TEG.

Risk factors of massive blood transfusion in liver transplantation: consequences and a new index for prediction including the donor

BACKGROUND

Massive blood transfusion (MBT) is a common occurrence in liver transplant (LT) patients. Recipient-related risk factors include cirrhosis, history of multiple surgeries and suboptimal donors. Despite advances in surgical techniques, anesthetic management and graft preservation have decreased the need for transfusions, this complication has not been completely eliminated.

METHODS

One thousand four hundred and sixty-nine LT were performed at our institution between May 2003 and December 2020, and data was available regarding transfusion for 1198 of them. We divided the patients into two groups, with regards to transfusion of 6 or more units of packed red blood cells in the first 24 h posttransplant, and we analyzed the differences between the groups.

RESULTS

Out of the 1198 patients, 607 (50.7%) met criteria for MBT. Survival was statistically lower at 1, 3, and 5 years when comparing the groups that had MBT to those that did not (92.6%, 85.2% and 79.7%, respectively, in the non MBT group, vs. 78.1%, 71.6% y 66.8%, respectively, in the MBT group). MBT was associated with a 1.5 mortality risk as opposed to non-MBT patients. Logistical regression analysis of our variables yielded the following results for a new model, including serum creatinine (OR 1.97), sodium (OR 1.73), hemoglobin (OR 1.99), platelets (OR 1.37), INR (OR 1.4), uDCD (OR 2.13) and split liver donation.

CONCLUSION

Massive blood transfusion impacts patient survival in a statistically significant way. The most significant risk factors are preoperative hemoglobin, INR and serum creatinine.

Comparison of the modified piggyback with standard piggyback and conventional orthotopic liver transplantation techniques: a network meta-analysis

BACKGROUND

In conventional orthotopic liver transplantation (OLT), the recipient's retrohepatic inferior vena cava (IVC) is completely clamped and replaced with the donor IVC. The piggyback technique has been used to preserve venous return, either via an end-to-side or standard piggyback (SPB), or via a side-to-side or modified piggyback (MPB) anastomosis, using a venous cuff from the recipient hepatic veins with partially clamping and preserves the recipient's inferior vena cava. However, whether these piggyback techniques improve the efficacy of OLT is unclear. To address the low quality of the available evidence, we performed a meta-analysis to compare the efficacy of conventional, MPB, and SPB techniques.

METHODS

Literature was searched in Medline and Web of Science databases for relevant articles published until 2021 without any time restriction. A Bayesian network meta-analysis was performed to compare the intra- and postoperative outcomes of conventional OLT, MPB, and SPB techniques.

RESULTS

Forty studies were included, comprising 10,238 patients. MPB and SPB had significantly shorter operation times and fewer transfusions of red blood cell and fresh frozen plasma than conventional techniques. However, there were no differences between MPB and SPB in operation time and blood product transfusion. There were also no differences in primary non-function, retransplantation, portal vein thrombosis, acute kidney injury, renal dysfunction, venous outflow complications, length of hospital and intensive care unit stay, 90-day mortality rate, and graft survival between the three techniques.

CONCLUSION

MBP and SBP techniques reduce the operation time and need for blood transfusion compared with conventional OLT, but postoperative outcomes are similar. This indicates that all techniques can be implemented based on the experience and policy of the transplant center.

Effect of targeted coagulopathy management and 5% albumin as volume replacement therapy during lung transplantation on allograft function: a secondary analysis of a randomized clinical trial

BACKGROUND

Primary graft dysfunction (PGD) after lung transplantation (LuTx) contributes substantially to early postoperative morbidity. Both intraoperative transfusion of a large amount of blood products during the surgery and ischemia-reperfusion injury after allograft implantation play an important role in subsequent PGD development.

METHODS

We have previously reported a randomized clinical trial of 67 patients where point of care (POC) targeted coagulopathy management and intraoperative administration of 5% albumin led to significant reduction of blood loss and blood product consumption during the lung transplantation surgery. A secondary analysis of the randomized clinical trial evaluating the effect of targeted coagulopathy management and intraoperative administration of 5% albumin on early lung allograft function after LuTx and 1-year survival was performed.

RESULTS

Compared to the patients in the control (non-POC) group, those in study (POC) group showed significantly superior graft function, represented by the Horowitz index (at 72 h after transplantation 402.87 vs 308.03 with p < 0.001, difference between means: 94.84, 95% CI: 60.18-129.51). Furthermore, the maximum doses of norepinephrine administered during first 24 h were significantly lower in the POC group (0.193 vs 0.379 with p < 0.001, difference between the means: 0.186, 95% CI: 0.105-0.267). After dichotomization of PGD (0-1 vs 2-3), significant difference between the non-POC and POC group occurred only at time point 72, when PGD grade 2-3 developed in 25% (n = 9) and 3.2% (n = 1), respectively (p = 0.003). The difference in 1-year survival was not statistically significant (10 patients died in non-POC group vs. 4 patients died in POC group; p = 0.17).

CONCLUSIONS

Utilization of a POC targeted coagulopathy management combined with Albumin 5% as primary resuscitative fluid may improve early lung allograft function, provide better circulatory stability during the early post-operative period, and have potential to decrease the incidence of PGD without negative effect on 1-year survival.

TRIAL REGISTRATION

This clinical trial was registered at ClinicalTrials.gov (NCT03598907).

Preoperative Fibrinogen Level and Bleeding in Liver Transplantation for End-stage Liver Disease: A Cohort Study

BACKGROUND

Liver transplantation is a high-risk surgery associated with important perioperative bleeding and transfusion needs. Uncertainties remain on the association between preoperative fibrinogen level and bleeding in this population.

METHODS

We conducted a cohort study that included all consecutive adult patients undergoing a liver transplantation for end-stage liver disease in 1 center. We analyzed the association between the preoperative fibrinogen level and bleeding-related outcomes. Our primary outcome was intraoperative blood loss, and our secondary outcomes were estimated perioperative blood loss, intraoperative and perioperative red blood cell transfusions, reinterventions for bleeding and 1-y graft and patient survival. We estimated linear regression models and marginal risk models adjusted for all important potential confounders. We used restricted cubic splines to explore potential nonlinear associations and reported dose-response curves.

RESULTS

We included 613 patients. We observed that a lower fibrinogen level was associated with a higher intraoperative blood loss, a higher estimated perioperative blood loss and a higher risk of intraoperative and perioperative red blood cell transfusions (nonlinear effects). Based on an exploratory analysis of the dose-response curves, these effects were observed below a threshold value of 3 g/L for these outcomes. We did not observe any association between preoperative fibrinogen level and reinterventions, 1-y graft survival or 1-y patient survival.

CONCLUSIONS

This study suggests that a lower fibrinogen level is associated with bleeding in liver transplantation. The present results may help improving the selection of patients for further studies on preoperative fibrinogen administration in liver transplant recipients with end-stage liver disease.

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

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

Blood products and liver transplantation: A strategy to balance optimal preparation with effective blood stewardship

BACKGROUND

Unanticipated transfusion requirements during liver transplantation can delay lifesaving intraoperative resuscitation and strain blood bank resources. Risk-stratified preoperative blood preparation can mitigate these deleterious outcomes.

STUDY DESIGN AND METHODS

A two-tiered blood preparation protocol for liver transplantation was retrospectively evaluated. Eleven binary variables served as criteria for high-risk (HR) allocation. Primary outcomes included red blood cell (RBC), plasma (FFP), and platelet (Plt) utilization. Secondary outcomes included product under- and overpreparation. Contingency tables for transfusion requirements above the population means were generated using 15 clinical variables. Modified protocols were developed and retrospectively optimized using the study population.

RESULTS

Of 225 recipients, 102 received HR preoperative orders, which correlated to higher intraoperative transfusion requirements. However, univariate analysis identified only two statistical risk factors per product: Hgb ≤7.8 g/dl (p < .001) and MELD ≥38 (p = .035) for RBCs, Hgb ≤7.8 g/dl (p = .002) and acute alcoholic hepatitis (p = 0.015) for FFP, and Hgb ≤7.8 g/dl (p = .001) and normothermic liver preservation (p = .037) for Plts. Based on these findings, we developed modified protocols for individual products, which were evaluated retrospectively for their effectiveness at reducing under-preparatory events while limiting product overpreparation. Cohort statistics were used to define the preparation strategy for each protocol. Retrospective comparative analysis demonstrated the superiority of the modified protocols by improving the under-preparation rate from 24% to <10% for each product, which required a 1.56-fold and 1.44-fold increase in RBC and FFP overpreparation, respectively. Importantly, there was no difference in Plt overpreparation.

DISCUSSION

We report translatable data-driven blood bank preparation protocols for liver transplantation.

Validation of 5 models predicting transfusion, bleeding, and mortality in liver transplantation: an observational cohort study

BACKGROUND

Historically, orthotopic liver transplantation (OLT) has been associated with massive blood loss, blood transfusion and morbidity. In order to predict such outcomes five nomograms have been published relating to transfusions and morbidity associated with OLTs. These nomograms, developed on the basis of three cohorts of patients consisting of 406, 750, and 800 having undergone OLTs, aimed to predict a transfusion of ≥1 red blood cell unit (RBC), a transfusion of >2 RBC units, a blood loss of >900 ml, as well as one-month and one-year survival rates. The aim of this study was to validate these five nomograms in a contemporary, independent cohort of patients.

METHODS

Five nomograms were previously developed based on 406, 750, and 800 OLTs. In this study we performed a temporal validation of these nomograms on contemporary patients that consisted of three cohorts of 800, 250, and 200 OLTs. Logistic regression coefficients from the historic development cohorts were applied to the three contemporary temporal validation cohorts.

RESULTS

The most accurate nomogram was able to predict transfusion of ≥1 RBC units with an area under the curve (AUC) was 0.91. The second-best nomogram was able to predict bleeding of >900 ml with an AUC of 0.70. T he AUC of the third nomogram (transfusion of >2 RBC units) was 0.70. However, is temporal validation was suboptimal, due to a low prevalence of OLTs transfused with >2 RBC units. The last 2 nomograms exhibited clearly suboptimal AUC values of 0.54 and 0.61.

CONCLUSION

Two of the five nomograms predict blood transfusion and blood loss with excellent accuracy. Transfusion of ≥1 RBC unit and blood loss of >900 ml can be predicted on the basis of these nomograms. However, these nomograms are not accurate to predict one-month and one-year survival rates. These results should be further cross-validated, ideally prospectively, in additional external independent cohorts.

Consensus Statement on Hemostatic Management, Anticoagulation, and Antiplatelet Therapy in Liver Transplantation

Anticoagulation and antiplatelet therapies are increasingly used in liver transplant (LT) candidates and recipients due to cardiovascular comorbidities, portal vein thrombosis, or to manage posttransplant complications. The implementation of the new direct-acting oral anticoagulants and the recently developed antiplatelet drugs is a great challenge for transplant teams worldwide, as their activity must be monitored and their complications managed, in the absence of robust scientific evidence. In this changing and clinically heterogeneous scenario, the Spanish Society of Liver Transplantation and the Spanish Society of Thrombosis and Haemostasis aimed to achieve consensus regarding the indications, drugs, dosing, and timing of anticoagulation and antiplatelet therapies initiated from the inclusion of the patient on the waiting list to post-LT surveillance. A multidisciplinary group of experts composed by transplant hepatologists, surgeons, hematologists, transplant-specialized anesthesiologists, and intensivists performed a comprehensive review of the literature and identified 21 clinically relevant questions using the patient-intervention-comparison-outcome format. A preliminary list of recommendations was drafted and further validated using a modified Delphi approach by a panel of 24 transplant delegates, each representing a LT institution in Spain. The present consensus statement contains the key recommendations together with the core supporting scientific evidence, which will provide guidance for improved and more homogeneous clinical decision making.

Association of Plasma Fibrinogen Levels on Postoperative Day 1 with 2-Year Survival of Orthotopic Liver Transplantation for HBV-Related HCC

OBJECTIVE

To clarify the prognostic values of hemostatic parameters to predict the survival of patients undergoing orthotopic liver transplantation (OLT) for hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC).

METHODS

The data of 182 consecutive adult patients who underwent OLT for HBV-related HCC were subjected to univariate and multivariate analyses.

RESULTS

Ascites and fibrinogen levels on postoperative day (POD) 1 were independent predictors of postoperative 2-year mortality (both P <.05). Kaplan-Meier survival analysis showed that the higher the fibrinogen level on POD 1, the better the 1- and 2-year survival of patients with ascites (P <.05), whereas the fibrinogen level on POD 1 was associated with 1-year (P <.05) but not 2-year survival of patients without ascites.

CONCLUSION

Fibrinogen on POD 1 is a predictor of 2-year post-OLT survival of patients with HBV-related HCC with ascites.

Recipient liver splitting to facilitate piggyback hepatectomy in adult living donor liver transplantation

Recipient hepatectomy for an enlarged stony-hard liver is a demanding procedure, thus it is often accompanied by massive blood loss. Recipient liver splitting under prolonged hepatic inflow occlusion would facilitate the piggyback recipient hepatectomy. We herein present a case of recipient liver splitting, which was used for living donor liver transplantation (LDLT). A 48-year-old male patient diagnosed with acute-on-chronic liver failure underwent LDLT. During the recipient operation, the native liver was stony-hard and heavily adherent to the retrohepatic inferior vena cava (IVC). During liver mobilization, diffuse oozing occurred due to disseminated intravascular coagulation. As a change in the concept, we decided to perform in situ liver splitting of the recipient liver to facilitate dissection of the retrohepatic IVC. Under hepatic inflow occlusion, right-left liver splitting was performed along the usual plane of extended left hepatectomy. The procedures time for recipient liver splitting and removal was 60 minutes. A modified right liver graft recovered from his daughter was implanted according to the standard procedures of LDLT. We think that recipient liver splitting is a feasible technical option for coping with difficult recipient hepatectomy, especially in patients with an enlarged stony-hard liver and heavy adhesion around the IVC.

Cell Salvage During Liver Transplantation for Hepatocellular Carcinoma: A Retrospective Analysis of Tumor Recurrence Following Irradiation of the Salvaged Blood

BACKGROUND

Orthotopic liver transplantation (OLT) is the treatment option for early-stage hepatocellular carcinoma (HCC). OLT is often associated with high blood loss, requiring blood transfusion. Retransfusion of autologous blood is a key part of blood conservation. There are, however, concerns that the retransfusion of salvaged blood might cause the spread of cancer cells and induce metastasis. Irradiation of salvaged blood before retransfusion eliminates viable cancer cells. Here, we analyzed the incidence of tumor recurrence in patients with HCC undergoing OLT who received irradiated cell-salvaged blood during transplant surgery.

METHODS

We retrospectively analyzed patients undergoing OLT for HCC between 2002 and 2018 at our center. We compared the tumour recurrence in patients who received no retransfusion of autologous blood with patients who received autologous blood with or without preceding irradiation of the blood.

RESULTS

Fifty-one (40 male, 11 female) patients were included in the analysis; 10 patients developed tumor recurrence within a time period of 2.45 ± 2.0 years. Statistical analysis revealed that there was no significant difference in tumor recurrence between patients who received autologous blood with or without irradiation.

CONCLUSION

Intraoperative transfusion of cell-salvaged blood did not increase tumor recurrence rates. Cell salvage should be used in liver transplantation of HCC patients as part of a blood conservation strategy. The effect of blood irradiation on tumor recurrence could not be definitively evaluated.

Machine Learning for the Prediction of Red Blood Cell Transfusion in Patients During or After Liver Transplantation Surgery

Aim: This study aimed to use machine learning algorithms to identify critical preoperative variables and predict the red blood cell (RBC) transfusion during or after liver transplantation surgery. Study Design and Methods: A total of 1,193 patients undergoing liver transplantation in three large tertiary hospitals in China were examined. Twenty-four preoperative variables were collected, including essential population characteristics, diagnosis, symptoms, and laboratory parameters. The cohort was randomly split into a train set (70%) and a validation set (30%). The Recursive Feature Elimination and eXtreme Gradient Boosting algorithms (XGBOOST) were used to select variables and build machine learning prediction models, respectively. Besides, seven other machine learning models and logistic regression were developed. The area under the receiver operating characteristic (AUROC) was used to compare the prediction performance of different models. The SHapley Additive exPlanations package was applied to interpret the XGBOOST model. Data from 31 patients at one of the hospitals were prospectively collected for model validation. Results: In this study, 72.1% of patients in the training set and 73.2% in the validation set underwent RBC transfusion during or after the surgery. Nine vital preoperative variables were finally selected, including the presence of portal hypertension, age, hemoglobin, diagnosis, direct bilirubin, activated partial thromboplastin time, globulin, aspartate aminotransferase, and alanine aminotransferase. The XGBOOST model presented significantly better predictive performance (AUROC: 0.813) than other models and also performed well in the prospective dataset (accuracy: 76.9%). Discussion: A model for predicting RBC transfusion during or after liver transplantation was successfully developed using a machine learning algorithm based on nine preoperative variables, which could guide high-risk patients to take appropriate preventive measures.

Transfusion Status in Liver and Kidney Transplantation Recipients-Results from Nationwide Claims Database

BACKGROUND

This study analyzed the status and trends of transfusion and its associated factors among liver and kidney transplantation recipients.

METHODS

A total of 10,858 and 16,191 naïve liver or kidney transplantation recipients from 2008 to 2017 were identified through the National Health Insurance Service database. The prescription code for transfusion and the presence, number, and amount of each type of transfusion were noted. The odds ratios and 95% confidence intervals were determined to identify significant differences in transfusion and blood components by liver and kidney transplantation recipient characteristics.

RESULTS

In this study, 96.4% of liver recipients and 59.7% of kidney recipients received transfusions related to the transplantation operation, mostly platelet and fresh frozen plasma. Higher perioperative transfusion in women and declining transfusion rates from 2008 to 2017 were observed in both liver and kidney recipients. In liver recipients, the transfusion rate in those who received organs from deceased donors was much higher than that in those who received organs from living donors; however, the mortality rate according to transfusion was higher only in recipients of deceased donor organs. In kidney recipients, a higher mortality rate was observed in those receiving transfusion than that in patients without transfusion.

CONCLUSIONS

In Korea, the transfusion rates in liver and kidney recipients were relatively higher than those in other countries. Sociodemographic factors, especially sex and year of transplantation, were associated with transfusion in solid organ recipients, possibly as surrogates for other causal clinical factors.

Analysis of the hemostatic therapy in liver transplantation guided by rotational thromboelastometry or conventional laboratory tests

BACKGROUND

Coagulopathy is quite common in chronic liver disease patients undergoing orthotopic liver transplantation (OLT). Diagnosis of intraoperative bleeding disorders is based on conventional laboratory tests (CLTs), and thus, the patients are frequently exposed to unnecessary transfusions of blood products. The present study aimed to analyze the intraoperative administration of blood products in patients undergoing OLT, using rotational thromboelastometry (ROTEM) or CLTs.

PATIENTS AND METHODS

A cohort comprising 153 patients undergoing OLT, of whom 82 were evaluated with ROTEM and 71 by CLTs. Both groups were analyzed intraoperatively: the transfusion of blood products.

RESULTS

The incidence of patients transfused with cryoprecipitate (CRYO) and/or fibrinogen concentrate (54.9 vs. 19.7%; P < 0.001) and prothrombin complex concentrate (PCC) (32.9 vs. 9.9%; P = 0.008) increased significantly in the ROTEM group than in CLT group, respectively. The amount of transfused patient with CRYO (7.6 vs. 1.2; P < 0.001), fibrinogen concentrate (0.8 vs. 0.2; P = 0.004) and PCC (1.4 vs. 0.2; P = 0.002) increased significantly in the ROTEM group than in the CLT group, respectively. In the analysis of fresh-frozen plasma (FFP), the incidence of transfused patients was significantly higher in the CLT group than in the ROTEM group (46.5 vs. 30.5%; P = 0.047, respectively), with a moderate correlation with red blood cells transfusion (r = 0.67, P < 0.001). The incidence of patients receiving antifibrinolytics was significantly higher in the CLT group than in the ROTEM group (85.9 vs. 47.6%; P < 0.001, respectively).

CONCLUSION

Transfusion protocol-based thromboelastometry was able to guide administration of hemostatic factors and reduced administration of FFP and antifibrinolytics.

Effects of Intraoperative Fluid Balance During Liver Transplantation on Postoperative Acute Kidney Injury: An Observational Cohort Study

BACKGROUND

Liver transplant recipients suffer many postoperative complications. Few studies evaluated the effects of fluid management on these complications. We conducted an observational cohort study to evaluate the association between intraoperative fluid balance and postoperative acute kidney injury (AKI) and other postoperative complications.

METHODS

We included consecutive adult liver transplant recipients who had their surgery between July 2008 and December 2017. Our exposure was intraoperative fluid balance, and our primary outcome was the grade of AKI at 48 hours after surgery. Our secondary outcomes were the grade of AKI at 7 days, the need for postoperative renal replacement therapy, postoperative red blood cell transfusions, time to first extubation, time to discharge from the intensive care unit (ICU), and 1-year survival. Every analysis was adjusted for potential confounders.

RESULTS

We included 532 transplantations in 492 patients. We observed no effect of fluid balance on either 48-hour AKI, 7-day AKI, or on the need for postoperative renal replacement therapy after adjustments for confounders. A higher fluid balance increased the time to ICU discharge, and increased the risk of dying (hazard ratio = 1.21 [1.04,1.40]).

CONCLUSIONS

We observed no association between intraoperative fluid balance and postoperative AKI. Fluid balance was associated with longer time to ICU discharge and lower survival. This study provides insight that might inform the design of a clinical trial on fluid management strategies in this population.

Validation of predictive models identifying patients at risk for massive transfusion during liver transplantation and their potential impact on blood bank resource utilization

BACKGROUND

Intraoperative massive transfusion (MT) is common during liver transplantation (LT). A predictive model of MT has the potential to improve use of blood bank resources.

STUDY DESIGN AND METHODS

Development and validation cohorts were identified among deceased-donor LT recipients from 2010 to 2016. A multivariable model of MT generated from the development cohort was validated with the validation cohort and refined using both cohorts. The combined cohort also validated the previously reported McCluskey risk index (McRI). A simple modified risk index (ModRI) was then created from the combined cohort. Finally, a method to translate model predictions to a population-specific blood allocation strategy was described and demonstrated for the study population.

RESULTS

Of the 403 patients, 60 (29.6%) in the development and 51 (25.5%) in the validation cohort met the definition for MT. The ModRI, derived from variables incorporated into multivariable model, ranged from 0 to 5, where 1 point each was assigned for hemoglobin level of less than 10 g/dL, platelet count of less than 100 × 10⁹ /dL, thromboelastography R interval of more than 6 minutes, simultaneous liver and kidney transplant and retransplantation, and a ModRI of more than 2 defined recipients at risk for MT. The multivariable model, McRI, and ModRI demonstrated good discrimination (c statistic [95% CI], 0.77 [0.70-0.84]; 0.69 [0.62-0.76]; and 0.72 [0.65-0.79], respectively, after correction for optimism). For blood allocation of 6 or 15 units of red blood cells (RBCs) based on risk of MT, the ModRI would prevent unnecessary crossmatching of 300 units of RBCs/100 transplants.

CONCLUSIONS

Risk indices of MT in LT can be effective for risk stratification and reducing unnecessary blood bank resource utilization.

A clinical coagulopathy score concurrent with viscoelastic testing defines opportunities to improve hemostatic resuscitation and enhance blood product utilization during liver transplantation

BACKGROUND

An NIH clinical coagulopathy score has been devised for trauma patients, but no such clinical score exists in transplantation surgery. We hypothesize that that this coagulopathy score can effectively identify laboratory defined coagulopathy during liver transplantation and correlates to blood product utilization.

METHODS

TEGs were performed and coagulopathy scores (1, normal bleeding - 5, diffuse coagulopathic bleeding) were assigned by the surgeons at 5 intra-operative time points. Blood products used during the case were recorded between time points. Statistical analyses were performed to identify correlations between coagulopathy scores, TEG-detected abnormalities, and blood product utilization.

RESULT

Transfusions rarely correlated with the appropriate TEG measurements of coagulation dysfunction. Coagulopathy score had significant correlation to various transfusions and TEG-detected coagulopathies at multiple points during the case. High aggregate coagulopathy scores identified patients receiving more transfusions, re-operations, and longer hospital stays CONCLUSION: The combination of viscoelastic testing and a standardized clinical coagulopathy score has the potential to optimize transfusions if used in tandem as well as standardize communication between surgery and anesthesia teams about clinically evident coagulopathy.

Anticoagulant Management and Synthesis of Hemostatic Proteins during Machine Preservation of Livers for Transplantation

Liver transplantation remains the only curative treatment for patients with end-stage liver disease. Despite a steadily increasing demand for suitable donor livers, the current pool of donor organs fails to meet this demand. To resolve this discrepancy, livers traditionally considered to be of suboptimal quality and function are increasingly utilized. These marginal livers, however, are less tolerant to the current standard cold preservation of donor organs. Therefore, alternative preservation methods have been sought and are progressively applied into clinical practice. Ex situ machine perfusion is a promising alternative preservation modality particularly for suboptimal donor livers as it provides the ability to resuscitate, recondition, and test the viability of an organ prior to transplantation. This review addresses the modalities of machine perfusion currently being applied, and particularly focuses on the hemostatic management employed during machine perfusion. We discuss the anticoagulant agents used, the variation in dosage, and administration, as well as the implications of perfusion for extended periods of time in terms of coagulation activation associated with production of coagulation factors during perfusion. Furthermore, in regard to viability testing of an organ prior to transplantation, we discuss the possibilities and limitations of utilizing the synthesis of liver-derived coagulation factors as potential viability markers.

Anaesthesia for Liver Transplantation: An Update

Liver transplantation (LT) is a challenging surgery performed on patients with complex physiology profiles, complicated by multi-system dysfunction. It represents the treatment of choice for end-stage liver disease. The procedure is performed under general anaesthesia, and a successful procedure requires an excellent understanding of the patho-physiology of liver failure and its implications. Despite advances in knowledge and technical skills and innovations in immunosuppression, the anaesthetic management for LT can be complicated and represent a real challenge. Monitoring devices offer crucial information for the successful management of patients. Hemodynamic instability is typical during surgery, requiring sophisticated invasive monitoring. Arterial pulse contour analysis and thermo-dilution techniques (PiCCO), rotational thromboelastometry (RO-TEM), transcranial doppler (TCD), trans-oesophageal echocardiography (TEE) and bispectral index (BIS) have been proven to be reliable monitoring techniques playing a significant role in decision making. Anaesthetic management is specific according to the three critical phases of surgery: pre-anhepatic, anhepatic and neo-hepatic phase. Surgical techniques such as total or partial clamping of the inferior vena cava (IVC), use of venovenous bypass (VVBP) or portocaval shunts have a significant impact on cardiovascular stability. Post reperfusion syndrome (PRS) is a significant event and can lead to arrhythmias and even cardiac arrest.

Liver transplantation in Jehovah's witnesses: 13 consecutive cases at a single institution

Background

Jehovah’s Witnesses represent a tremendous clinical challenge when indicated to liver transplantation because they refuse blood transfusion on religious grounds and the procedure is historically associated with potential massive peri-operative blood loss. We herein describe a peri-operative management pathway with strategies toward a transfusion-free environment with the aim not only of offering liver transplant to selected Jehovah’s Witnesses patients but also, ultimately, of translating this practice to all general surgical procedures.

Methods

This is a retrospective review of prospective medical records of JW patients who underwent LT at our Institution. The peri-operative multimodal strategy to liver transplantation in Jehovah’s Witnesses includes a pre-operative red cell mass optimization package and the intra-operative use of normovolemic haemodilution, veno-venous bypass and low central venous pressure.

Results

In a 9-year period, 13 Jehovah’s Witness patients received liver transplantation at our centre representing the largest liver transplant program from deceased donors in Jehovah’s Witnesses patients reported so far. No patient received blood bank products but 3 had fibrinogen concentrate and one tranexamic acid to correct ongoing hyper-fibrinolysis. There were 4 cases of acute kidney injury (one required extracorporeal renal replacement treatment) and one patient needed vasoactive medications to support blood pressure for the first 2 postoperative days. Two patients underwent re-laparotomy. Finally, of the 13 recipients, 12 were alive at the 1 year follow-up interview and 1 died due to septic complications.

Conclusions

Our experience confirms that liver transplantation in selected Jehovah’s Witnesses patients can be feasible and safe provided that it is carried out at a very experienced centre and according to a multidisciplinary approach.

Liver Transplantation

The field of liver transplantation has changed since the MELD scoring system became the most widely used donor allocation tool. Due to the MELD-based allocation system, sicker patients with higher MELD scores are being transplanted. Persistent organ donor shortages remain a challenging issue, and as a result, the wait-list mortality is a persistent problem for most of the regions. This chapter focuses on deceased donor and live donor liver transplantation in patients with complications of portal hypertension. Special attention will also be placed on donor-recipient matching, perioperative management of transplant patients, and the impact of hepatic hemodynamics on transplantation.

Intensive Care Unit Enhanced Recovery Pathway for Patients Undergoing Orthotopic Liver Transplants Recipients: A Prospective, Observational Study

BACKGROUND

Liver transplant recipients continue to have high perioperative resource utilization and prolonged length of stay despite improvements in perioperative care. Enhanced recovery pathways have been shown in other surgical populations to produce reductions in hospital resource utilization.

METHODS

A prospective, observational study was performed to examine the effect of an enhanced recovery pathway for postoperative care after liver transplantation. Outcomes from patients undergoing liver transplantation from November 1, 2013, to October 31, 2014, managed by the pathway were compared to transplant recipients from the year before pathway implementation. Multivariable regression analysis was used to assess the association of the clinical pathway on clinical outcomes.

RESULTS

The intervention and control groups included 141 and 106 patients, respectively. There were no demographic differences between the control and intervention group including no differences between the length of surgery and cold ischemic time. Median intensive care unit length of stay was reduced from 4.4 to 2.6 days (P < .001). The intervention group had a higher likelihood of earlier discharge (hazard ratio [95% CI], 2.01 [1.55-2.62]; P < .001), and a 69% and 65% lower odds of receiving a plasma (P < .001) or packed red blood cell (P < .001) transfusion. There was no significant effect on hospital mortality (P = .40), intensive care unit readmission rates (P = .75), or postoperative infections (urinary traction infections: P = .09; pneumonia: P = .27).

CONCLUSIONS

An enhanced recovery pathway focused on milestone-based elements of intensive care unit management and predetermined management triggers including hemodynamic goals, fluid therapy, perioperative antibiotics, glycemic control, and standardized transfusion triggers led to reductions in intensive care unit length of stay without an increase in perioperative complications.

Intrahepatic fibrin(ogen) deposition drives liver regeneration after partial hepatectomy in mice and humans

Platelets play a pivotal role in stimulating liver regeneration after partial hepatectomy in rodents and humans. Liver regeneration in rodents is delayed when platelets are inhibited. However, the exact mechanisms whereby platelets accumulate and promote liver regeneration remain uncertain. Thrombin-dependent intrahepatic fibrin(ogen) deposition was recently reported after partial hepatectomy (PHx) in mice, but the role of fibrin(ogen) deposits in liver regeneration has not been investigated. We tested the hypothesis that fibrin(ogen) contributes to liver regeneration by promoting intrahepatic platelet accumulation and identified the trigger of rapid intrahepatic coagulation after PHx. PHx in wild-type mice triggered rapid intrahepatic coagulation, evidenced by intrahepatic fibrin(ogen) deposition. Intrahepatic fibrin(ogen) deposition was abolished in mice with liver-specific tissue factor deficiency, pinpointing the trigger of coagulation after PHx. Direct thrombin activation of platelets through protease-activated receptor-4 did not contribute to hepatocyte proliferation after PHx, indicating that thrombin contributes to liver regeneration primarily by driving intrahepatic fibrin(ogen) deposition. Fibrinogen depletion with ancrod reduced both intrahepatic platelet accumulation and hepatocyte proliferation after PHx, indicating that fibrin(ogen) contributes to liver regeneration after PHx by promoting intrahepatic platelet accumulation. Consistent with the protective function of fibrin(ogen) in mice, low postoperative plasma fibrinogen levels were associated with liver dysfunction and mortality in patients undergoing liver resection. Moreover, increased intrahepatic fibrin(ogen) deposition was evident in livers of patients after liver resection but was remarkably absent in patients displaying hepatic dysfunction postresection. The results suggest a novel mechanism whereby coagulation-dependent intrahepatic fibrin(ogen) deposition drives platelet accumulation and liver regeneration after PHx.

Strategies to avoid empiric blood product administration in liver transplant surgery

Massive blood loss has been a dreaded complication of liver transplantation, and the accompanying transfusion is associated with adverse outcomes in the form of decreased patient and graft survival. With advances in both surgical techniques and anesthetic management during transplantation, blood and blood products requirements reduced significantly. However, transfusion practices vary among different centers. The altered coagulation parameters in patients with liver cirrhosis results in a state of “rebalanced hemostasis” and patients are just as likely to clot as they are to bleed. Commonly used coagulation tests do not always reflect this new state and can, therefore, be misleading. Transfusion of blood products solely to correct abnormal parameters may worsen the coagulation status, thus adversely affecting patient outcome. Point-of-care tests such as thromboelastometry more reliably predict the risk of bleeding in these patients and in addition may provide quicker turnaround times compared to routine tests. Perioperative management should also include the possibility of thrombosis in these patients, and the use of low-molecular-weight heparin correlates with better patient survival. This review article aims to highlight the concept of rebalanced hemostasis, limitation of routine coagulation tests, and harmful effect of empiric transfusion of blood products.

Platelet transfusion: Current challenges

Since the late sixties, platelet concentrates are transfused to patients presenting with severe thrombocytopenia, platelet function defects, injuries, or undergoing surgery, to prevent the risk of bleeding or to treat actual hemorrhage. Current practices differ according to the country or even in different hospitals and teams. Although crucial advances have been made during the last decades, questions and debates still arise about the right doses to transfuse, the use of prophylactic or therapeutic strategies, the nature and quality of PC, the storage conditions, the monitoring of transfusion efficacy and the microbiological and immunological safety of platelet transfusion. Finally, new challenges are emerging with potential new platelet products, including cold stored or in vitro produced platelets. The most debated of these points are reviewed.

The Double Hazard of Bleeding and Thrombosis in Hemostasis From a Clinical Point of View: A Global Assessment by Rotational Thromboelastometry (ROTEM)

Hemostasis is a complex dynamic process involving bleeding and thrombosis as two end-points. Conventional coagulation tests which are measured in plasma examine only isolated portions of the coagulation cascade, thereby giving no information on important interactions essential to the clinical evaluation of hemostatic function. Thromboelastography (TEG), originally described in 1948 has improved over the decades and become a valuable tool of coagulation testing because of the limitations of standard coagulation tests. TEG is a technique that provides data about the entire coagulation system, from the beginning of clot formation to fibrinolysis, involving both cellular and plasma components of hemostasis. Rotational thromboelastometry (ROTEM) which evolved from TEG technology overcome several limitations of classical TEG while maintaining a good correlation with conventional TEG determination. ROTEM analyses are useful for rapid assessment of global clotting function in various clinical situations including liver transplantation, cardiac surgery, obstetrics, trauma, hemophilia and idiopathic thrombocytopenic purpura. ROTEM has been also reported to be useful in identifying various hypercoagulable conditions including major surgery, malignancy, Behcet’s disease and apheresis. Further developments in ROTEM based transfusion strategies may also reduce transfusion requirements and improve clinical outcomes by optimizing the administration of blood components. This is a literature review of ROTEM including its technique, interpretation and specially clinical applications in different scenarios of bleeding and thrombotic disorders.

Bleeding and thrombotic complications of pediatric liver transplant

BACKGROUND

Pediatric patients undergoing liver transplant are at significant risk for bleeding and thrombotic complications due to the complex nature of rebalanced hemostasis in patients with liver disease.

METHODS/OBJECTIVES

We reviewed records of 92 pediatric liver and multivisceral transplant cases at Duke University Medical Center between January 2009 and December 2015. The goal was to define the nature and incidence of bleeding and thrombotic complications in this cohort and define potential risk factors.

RESULTS

There were 24 major bleeding events in 19 transplants (incidence 20.7%) and 30 thrombotic events in 23 transplants (incidence 25%). Five of the 10 retransplantations were for vascular thrombotic complications. Thirty-day mortality was 4.9%, and three of these four deaths were due to vascular thrombosis. No bleeding events led to retransplantation or mortality. Prophylactic aspirin was associated with decreased risk of thrombosis without increased bleeding. Prophylactic heparin did not increase bleeding risk. Laboratory assays predicted events poorly, apparently failing to capture the nuanced and dynamic interplay between pro- and anticoagulant factors in the posttransplant patient.

CONCLUSIONS

Both bleeding and thrombosis are frequent in this population, but only thrombotic complications contributed to retransplantation and mortality. A standardized approach to coagulation testing and antithrombotic therapy may be useful in predicting and reducing adverse outcomes. Alternative approaches to monitoring hemostasis need to be prospectively investigated in this complex patient population.

[Prophylactic use of tranexamic acid in noncardiac surgery : Update 2017]

BACKGROUND

Minimising perioperative bleeding is a key goal of "patient blood management" programs. One component of respective strategies includes preventive inhibition of fibrinolysis using protease inhibitors, such as tranexamic acid (TXA). TXA inhibits plasminogen activation and plasmin-induced fibrin degradation.

OBJECTIVES

The present article provides an overview of the existing literature and TXA applications in the prophylaxis of perioperative bleeding.

METHODS

Literature search in PubMed/MEDLINE (U.S. National Library of Medicine®, Bethesda, MD, USA).

RESULTS

TXA reduces perioperative blood loss and transfusion requirements in several randomized controlled trials (RCTs) and meta-analyses in the field of hip and knee arthroplasty for both intravenous and topical use. Moreover, evidence favours use of TXA in complex spine surgery and reconstructive surgery (e. g. craniosynostosis in children). Single RCTs showed benefits of TXA in abdominal hysterectomy, open prostatectomy, liver surgery and actively bleeding trauma patients. For prophylaxis of peripartum haemorrhage (PPH) following vaginal delivery or Caesarean section, TXA cannot be routinely recommended, although evidence points to benefits in actively bleeding patients. A recommendation exists for the treatment of (active) PPH. For prophylactic perioperative administration, different dosage regimens exist for adults. Most often an initial i. v. bolus of 1 g or 10-15 mg/kg body weight with/without repetition after 6 h or continuous infusions over 8 h is administered. Increased rates of thromboembolic events were not noted.

CONCLUSION

Protease inhibitors such as TXA reduce perioperative blood loss and transfusion requirements in selected surgical fields.

Blood Product Transfusion in Liver Transplantation and its Impact on Short-term Survival

BACKGROUND

Estimation of the amount of blood products required during liver transplantation can help provision of adequate blood supply, minimize transfusion-associated complications, and plan for preventive measures in high risk patients.

OBJECTIVE

To investigate independent predictors of peri-operative blood product transfusion and its impact on short-term survival of liver transplant recipients.

METHODS

In a cross-sectional study, old charts of patients who underwent liver transplantation between March 2003 and March 2013 at Namazi Hospital, Shiraz, Iran, were reviewed. The mean amount of blood product utilized during surgery and hospital stay and the related factors, including demographic characteristics, pre-transplant laboratory data, pre-transplant clinical data, operation data, and post-transplantation data were recorded.

RESULTS

We studied 1198 patients who underwent liver transplantation. The mean±SD amounts of red blood cells, fresh frozen plasma, and platelet transfusion during surgery and hospital stay were 2.67±3.5, 2.06±3.8, and 1.6±3.8 units, respectively. The mortality rate was significantly higher in patients who received high amounts of blood products (p<0.001). The mean amount of blood products' utilized during operation was significantly (p<0.001) decreased from 2003 to 2013.The mean amount of packed cell usage during operation and hospital stay was significantly (p<0.001) correlated with age, technique of surgery, serum albumin level, cirrhosis, blood urea nitrogen, length of operation, and prothrombin time.

CONCLUSION

Pre-operative factors may predict blood transfusion requirements in patients undergoing liver transplantation. Therefore, evaluation of patients before operation should be considered to provide adequate blood supply and minimize transfusion-associated complications. Understanding pre-operative factors associated with rate of transfusion may help us to best utilize the limited available blood resources.

Coagulation Management During Liver Transplantation: Use of Fibrinogen Concentrate, Recombinant Activated Factor VII, Prothrombin Complex Concentrate, and Antifibrinolytics

Coagulation management, and transfusion practice in liver transplantation (LT) have been evolving in the recent years due to better understanding of coagulation abnormalities in end-stage liver disease, and clinical management of LT patients. Avoidance of allogeneic blood components is feasible in some patients, but multi-modal coagulation therapies may be necessary in others who develop complex coagulopathy due to hemorrhage, hemodilution, hypothermia, and acid-base disturbances. Transfusions of plasma and cryoprecipitate remain to be the mainstay therapy for procoagulant factor replacement during LT. Clinical efficacy and safety of these products are limited by logistic issues (eg, thawing), and mostly noninfectious complications. Considering potential alternatives to conventional transfusion is thus important to improve hemostatic resuscitation in complex LT cases. The present review is mainly focused on procoagulant properties of plasma and platelet transfusion, and currently available plasma-derived and recombinant factor concentrates, and antifibrinolytic agents in LT patients. The role of viscoelastic coagulation tests to guide specific component therapies will be also discussed.

Pathogenesis, prevention, and management of bleeding and thrombosis in patients with liver diseases

Patients with liver diseases may develop alterations in all components of the hemostatic system. Thrombocytopenia, low levels of coagulation factors and inhibitors, low levels of fibrinolytic proteins, and increased levels of endothelial-derived proteins such as von Willebrand factor are all part of the coagulopathy of liver disease. Due to concomitant changes in pro- and antihemostatic drivers, the net effects of these complex hemostatic changes have long been unclear. According to current concepts, the hemostatic system of patients with liver disease is in an unstable balance, which explains the occurrence of both bleeding and thrombotic complications. This review will discuss etiology and management of bleeding and thrombosis in liver disease and will outline unsolved clinical questions. In addition, we will discuss the role of intrahepatic activation of coagulation for progression of liver disease, a novel paradigm with potential consequences for the general management of patients with liver disease.

Transfusion Medicine and Coagulation Management in Organ Transplantation

Organ transplantation recipients present unusual challenges with regard to blood transfusion. Although this patient population requires a larger proportion of blood product resources, liberal transfusion of allogeneic blood products can lead to a plethora of complications. Recent trends suggest that efforts to minimize bleeding, conserve products, and target transfusion to specific deficits and needs are increasingly becoming the standard practice; these must all occur with optimization of graft function and preservation in mind. With newer monitoring modalities and factor concentrates, the approach toward transfusion and bleeding in organ transplantation has rapidly improved in recent years.

Incidence and predictors of massive bleeding in children undergoing liver transplantation: A single-center retrospective analysis

BACKGROUND

Liver transplantation represents a major surgery involving a highly vascular organ. Reports defining the scope of bleeding in pediatric liver transplants are few.

AIMS

We conducted a retrospective analysis of liver transplants performed at our pediatric tertiary care center to quantify blood loss, blood product utilization, and to determine predictors for massive intraoperative bleeding.

METHODS

Pediatric patients who underwent isolated liver transplantation at Boston Children's Hospital between 2011 and 2016 were included. The amount of blood product transfused in the perioperative period and the incidence of postoperative complications were reported. Univariable and multivariable logistic regressions were used to determine predictors for massive bleeding, defined as estimated blood loss exceeding one circulating blood volume within 24 hours.

RESULTS

Sixty-eight children underwent liver transplantation during the study period and were included in the analysis. Multivariable logistic regression analysis identified the following independent predictors of massive bleeding: preoperative hemoglobin level <8.5 g/dL (OR 11.09, 95% CI 1.87-65.76), INR >1.5 (OR 11.62, 95% CI 2.36-57.26), platelet count <100 10⁹ /L (OR 7.92, 95% CI 1.46-43.05), and surgery duration >600 minutes (OR 6.97, 95% CI 0.99-48.92).

CONCLUSIONS

Pediatric liver transplantation is associated with substantial blood loss and a significant blood product transfusion burden. A 43% incidence of massive bleeding is reported. Further efforts are needed to improve bleeding management in this high-risk population.

Thrombocytopenia in cirrhosis: Impact of fibrinogen on bleeding risk

AIM

To investigate the relationship between baseline platelet count, clauss fibrinogen, maximum amplitude (MA) on thromboelastography, and blood loss in orthotopic liver transplantation (OLT).

METHODS

A retrospective analysis of our OLT Database (2006-2015) was performed. Baseline haematological indices and intraoperative blood transfusion requirements, as a combination of cell salvage return and estimation of 300 mls/unit of allogenic blood, was noted as a surrogate for intraoperative bleeding. Two groups: Excessive transfusion (> 1200 mL returned) and No excessive transfusion (< 1200 mL returned) were analysed. All data analyses were conducted using IBM SPSS Statistics version 23.

RESULTS

Of 322 OLT patients, 77 were excluded due to fulminant disease; redo transplant or baseline haemoglobin (Hb) of < 80 g/L. One hundred and fourteen (46.3%) were classified into the excessive transfusion group, 132 (53.7%) in the no excessive transfusion group. Mean age and gender distribution were similar in both groups. Baseline Hb (P ≤ 0.001), platelet count (P = 0.005), clauss fibrinogen (P = 0.004) and heparinase MA (P = 0.001) were all statistically significantly different. Univariate logistic regression with a cut-off of platelets < 50 × 10⁹/L as the predictor and Haemorrhage as the outcome showed an odds ratio of 1.393 (95%CI: 0.758-2.563; P = 0.286). Review of receiver operating characteristic curves showed an area under the curve (AUC) for platelet count of 0.604 (95%CI: 0.534-0.675; P = 0.005) as compared with AUC for fibrinogen level, 0.678 (95%CI: 0.612-0.744; P ≤ 0.001). A multivariate logistic regression shows United Kingdom model for End Stage Liver Disease (P = 0.006), Hb (P = 0.022) and Fibrinogen (P = 0.026) to be statistically significant, whereas Platelet count was not statistically significant.

CONCLUSION

Platelet count alone does not predict excessive transfusion. Additional investigations, e.g., clauss fibrinogen and viscoelastic tests, provide more robust assessment of bleeding-risk in thrombocytopenia and cirrhosis.

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.