Evaluation of coagulation during treatment with directly acting antivirals in patients with hepatitis C virus related cirrhosis

Portal vein thrombosis: diagnosis, management, and endpoints for future clinical studies

Portal vein thrombosis (PVT) refers to the development of a non-malignant obstruction of the portal vein, its branches, its radicles, or a combination. This Review first provides a comprehensive overview of all aspects of PVT, namely the specifics of the portal venous system, the risk factors for PVT, the pathophysiology of portal hypertension in PVT, the interest in non-invasive tests, as well as therapeutic approaches including the effect of treating risk factors for PVT or cause of cirrhosis, anticoagulation, portal vein recanalisation by interventional radiology, and prevention and management of variceal bleeding in patients with PVT. Specific issues are also addressed including portal cholangiopathy, mesenteric ischaemia and intestinal necrosis, quality of life, fertility, contraception and pregnancy, and PVT in children. This Review will then present endpoints for future clinical studies in PVT, both in patients with and without cirrhosis, agreed by a large panel of experts through a Delphi consensus process. These endpoints include classification of portal vein thrombus extension, classification of PVT evolution, timing of assessment of PVT, and global endpoints for studies on PVT including clinical outcomes. These endpoints will help homogenise studies on PVT and thus facilitate reporting, comparison between studies, and validation of future studies and trials on PVT.

Predicting de-novo portal vein thrombosis after HCV eradication: A long-term competing risk analysis in the ongoing PITER cohort

BACKGROUND & AIMS

Sustained virological response (SVR) by direct-acting antivirals (DAAs) may reverse the hypercoagulable state of HCV cirrhosis and the portal vein thrombosis (PVT) risk. We evaluated the incidence and predictive factors of de novo, non-tumoral PVT in patients with cirrhosis after HCV eradication.

METHODS

Patients with HCV-related cirrhosis, consecutively enrolled in the multi-center ongoing PITER cohort, who achieved the SVR using DAAs, were prospectively evaluated. Kaplan-Meier and competing risk regression analyses were performed.

RESULTS

During a median time of 38.3 months (IQR: 25.1-48.7 months) after the end of treatment (EOT), among 1609 SVR patients, 32 (2.0%) developed de novo PVT. A platelet count ≤120,000/μL, albumin levels ≤3.5 mg/dL, bilirubin >1.1 mg/dL, a previous liver decompensation, ALBI, Baveno, FIB-4, and RESIST scores were significantly different (p < 0.001), among patients who developed PVT versus those who did not. Considering death and liver transplantation as competing risk events, esophageal varices (subHR: 10.40; CI 95% 4.33-24.99) and pre-treatment ALBI grade ≥2 (subHR: 4.32; CI 95% 1.36-13.74) were independent predictors of PVT. After HCV eradication, a significant variation in PLT count, albumin, and bilirubin (p < 0.001) versus pre-treatment values was observed in patients who did not develop PVT, whereas no significant differences were observed in those who developed PVT (p > 0.05). After the EOT, esophageal varices and ALBI grade ≥2, remained associated with de novo PVT (subHR: 9.32; CI 95% 3.16-27.53 and subHR: 5.50; CI 95% 1.67-18.13, respectively).

CONCLUSIONS

In patients with HCV-related cirrhosis, a more advanced liver disease and significant portal hypertension are independently associated with the de novo PVT risk after SVR.

Evaluation of Cardiovascular Risk Factors after Hepatitis C Virus Eradication with Direct-Acting Antivirals in a Cohort of Treatment-Naïve Patients without History of Cardiovascular Disease

Background: Hepatitis C virus (HCV) produces changes at multiple levels in host metabolism, especially in lipid profile and cardio-metabolic risk. It is unclear how HCV eradication by direct-acting antivirals (DAAs) modifies those changes. Objective: To evaluate the impact of DAA treatment on different risk factors associated with cardiovascular disease. Methods: Prospective study with two-year follow-up. All patients treated with DAAs in the Liver Clinic of a tertiary hospital were included. Patients co-infected with HBV or HIV, with other causes of liver disease, on lipid-lowering treatment, pregnant, or with previous HCV treatment were excluded. The results were analyzed using linear mixed models. Results: 167 patients (53% female, 9.6% cirrhosis) were included. Low plasma lipid levels were observed before initiating HCV eradication. During the first year after treatment with DAA, we observed a sustained increase in cholesterol, triglycerides, HDL cholesterol (only in men), and LDL-cholesterol levels. An ameliorated glycemic control was also observed with a decrease in fasting insulin and reduced HOMA. Iron metabolism and coagulation function also improved with lower levels of serum ferritin and prothrombin activity; these biochemical changes resulted in a new diagnosis of hypercholesterolaemia in 17.4% of patients, requiring initiation of statins in 15%. Two non-fatal cardiovascular events were observed during the first 2 years of follow-up. Conclusions: DAA treatments returned plasma lipids to the normal range without increasing either the occurrence of cardiovascular events or the consumption of lipid-lowering medication beyond what is normal in a sex- and age-matched population.

Risk of non-tumoural portal vein thrombosis in patients with HCV-induced cirrhosis after sustained virological response

BACKGROUND & AIMS

Sustained virological response (SVR) to direct-acting antivirals ameliorates portal hypertension, improves hepatic function and may reverse the procoagulant state observed in patients with cirrhosis. However, an unexpected incidence of portal vein thrombosis (PVT) immediately after antiviral therapy has recently been reported. Therefore, we analysed the long-term impact of SVR on the development of non-tumoural PVT.

METHODS

Our study comprised of two well-characterized prospective cohorts (hepatitis C virus '(HCV)-Cured': n = 354/'HCV-Active': n = 179) of patients with HCV cirrhosis who underwent standardized ultrasound surveillance. In the main analysis, the event of interest was de novo non-tumoural PVT and events known to modify its natural history (orthotopic liver transplantation, transjugular intrahepatic portosystemic shunt, death, tumoural PVT and anticoagulation) were considered as competing risk. Adjusted models were built using propensity scores for baseline covariates. Moreover, predictive factors were investigated by conventional multivariate analysis.

RESULTS

Ten (2.8%) patients in the 'HCV-Cured' cohort developed a non-tumoural PVT during a median follow-up of 37.1 months, while 8 (4.5%) patients in the 'HCV-Active' cohort were diagnosed with non-tumoural PVT during a median follow-up of 42.2 months. High Child-Pugh score was the only independent risk factor for non-tumoural PVT development and stage A patients were at low risk. Importantly, HCV cure did not decrease the risk of non-tumoural PVT in inverse probability of treatment-weighted (IPTW) analysis (subdistribution hazard ratio: 1.31 (95% confidence interval [95% CI]: 0.43-3.97); P = .635). In contrast, SVR was associated with a substantial reduction in mortality (IPTW-adjusted sHR: 0.453 [95% CI: 0.287-0.715]; P < .001).

CONCLUSIONS

The risk of non-tumoural PVT persists after HCV cure in patients with cirrhosis, despite improving survival. Even after aetiological cure, severity of liver disease remains the main determinant of non-tumoural PVT development.

Host pharmacogenetic factors that may affect liver neoplasm incidence upon using direct-acting antivirals for treating hepatitis C infection

Introduction

Direct-acting antivirals (DAAs) represent a breakthrough in hepatitis C virus (HCV) treatment as they directly inhibit HCV nonstructural (NS) proteins (NS3/4A, NS5A, and NS5B). However, ongoing debates exist regarding their relationship with hepatocellular carcinoma (HCC) whose incidence is widely debated among investigators. This study was conducted to identify host pharmacogenetic factors that may influence HCC incidence upon using HCV DAAs.

Materials and methods

Details regarding 16 HCV DAAs were collected from literature and DrugBank database. Digital structures of these drugs were fed into the pharmacogenomics/pharmacovigilance in-silico pipeline (PHARMIP) to predict the genetic factors that may underpin HCC development.

Results

We identified 184 unique genes and 40 unique variants that may have key answers for the DAA/HCC paradox. These findings could be used in different methods to aid in the precise application of HCV DAAs and minimize the proposed risk for HCC. All results could be accessed at: https://doi.org/10.17632/8ws8258hn3.2.

Discussion

All the identified factors are evidence related to HCC and significantly predicted by PHARMIP as DAA targets. We discuss some examples of the methods of using these results to address the DAA/HCC controversy based on the following three primary levels: 1 - individual DAA drug, 2 - DAA subclass, and 3 - the entire DAA class. Further wet laboratory investigation is required to evaluate these results.

Utility of viscoelastic coagulation testing in liver surgery: a systematic review

BACKGROUND

The objective of the current study was to summarize and evaluate all published evidence regarding viscoelastic testing in the field of liver surgery.

METHODS

A systematic search of the literature was performed using Medline/PubMed, Scopus, Cochrane Library Central, Google Scholar, and clinicaltrials.gov databases. The following keywords were used:"Thromboelastography", "Thromboelastometry", "Viscoelastic tests OR testing", "Sonoclot Devices", "Point-of-care tests OR testing", "Coagulation OR Haemostasis OR Hemostasis", "Liver OR Hepatic Surgery", "Cirrhosis."

RESULTS

A total of 12 studies analyzing 348 patients who underwent viscoelastic testing of coagulation during liver surgery for benign or malignant diseases were included; 7 (58.3%) studies reported on the use of thromboelastography (TEG), and 5 (41.7%) reported on rotational thromboelastometry (ROTEM). Viscoelastic testing (TEG and ROTEM) identified normo-, hyper- and hypo-coagulable status in 77% (n = 268/348), 18.4% (n = 64/348), and 4.6% (n = 16/348) of patients, respectively. In contrast, conventional coagulation tests indicated normo-coagulability in 111 patients (34.2% out of 325) and hypo-coagulability in 214 (65.8% out of 325) patients following liver resection. No patient (0% out of 291) experienced postoperative hemorrhage, whereas 5.8% (n = 17/291) experienced postoperative thromboembolic events.

CONCLUSIONS

Global viscoelastic testing may be a reasonable adjunct to conventional coagulation testing to provide a more robust assessment of the coagulation status of patients undergoing liver surgery.

Changes in plasma circulating microvesicles in patients with HCV-related cirrhosis after treatment with direct-acting antivirals

BACKGROUND & AIMS

The eradication of Hepatitis C (HCV) infection by direct-acting antiviral (DAAs) agents has been linked to an amelioration of liver synthesis and regression of fibrosis. Although changes in number and type of circulating microvesicles (MVs) have been reported in cirrhosis, conclusive data on the effect of DAAs treatment on MVs profile in HCV cirrhotic patients remain scarce.

METHODS

We measured the levels of endothelial, platelet and hepatocyte MVs, as well as MVs-expressing versican core protein (VCAN+) in patients with HCV-related cirrhosis at baseline, end of treatment (EOT), at 12, 24 and 48 weeks (W) after EOT by new generation flow cytometry.

RESULTS

Fifty-eight patients were enrolled (86% Child's A). MVs were increased at EOT vs baseline, though only platelet MVs revealed a statistically significant difference (P < .01). MV levels did not change significantly after EOT notwithstanding a steady downward trend towards baseline levels. Conversely, VCAN + MVs dropped significantly at EOT (P < .001) and remained low throughout the follow-up. Hepatocyte MVs significantly correlated with liver stiffness (r = .40, P = .0021). Eight composite outcomes occurred during the 1-year follow-up: three portal vein thromboses (PVTs), two hepatocellular carcinomas (HCCs) and three liver decompensation. Child's B, the presence of F2 oesophageal varices (OR for interaction 19.2 [95% CI 1.45-253.7], P = .023) and platelet MVs (OR 1.026 [95% CI 1.00-1.05, P = .023) correlated significantly with clinical outcomes.

CONCLUSIONS

VCAN + MVs appear to mirror the profibrotic status of the cirrhotic disease; hepatocyte MVs correlate with liver stiffness and increased platelet MV levels could be associated with a worse clinical outcome.

Procoagulant imbalance influences cardiovascular and liver damage in chronic hepatitis C independently of steatosis

BACKGROUND & AIMS

Patients with chronic HCV infection besides hepatitis often present cardiovascular damage, the pathogenesis of which is not defined. In chronic liver diseases, including NAFLD and cirrhosis, a procoagulant imbalance, potentially responsible for atherosclerosis has been reported. We aimed at evaluating whether a procoagulant imbalance is present also in non-cirrhotic patients with HCV infection and whether the procoagulant imbalance correlates with cardiovascular damage. The correlation between the procoagulant imbalance, coexisting steatosis, and liver fibrosis was analysed.

METHODS

From 2014 to 2018, 393 subjects (205 patients with chronic HCV infection from two liver units and 188 controls) were enrolled. Metabolic, cardiovascular, liver assessment and coagulation parameters-procoagulants (FII and FVIII) and anticoagulants (antithrombin and protein C [PC]), endogenous thrombin potential (ETP), peak-thrombin and their ratios (with/without thrombomodulin)-were determined.

RESULTS

The procoagulant imbalance (defined as high FVIII, FVIII/PC ratio, ETP-ratio and peak-thrombin-ratio (with/without thrombomodulin)) was significantly higher in patients with chronic HCV than controls. Steatosis was detected in 87 patients (42%). No difference in coagulation imbalance, carotid and cardiac parameters and severity of liver fibrosis was observed in patients with or without steatosis, despite the latter had less severe metabolic alterations. The FVIII/PC ratio was independently associated with carotid intima-media thickness (coefficient 0.04, 95% CI 0.002-0.07, P = .04) and liver fibrosis (coefficient 0.64, 95% CI 0.37-0.92, P < .0001).

CONCLUSION

Patients with HCV infection, even in the absence of cirrhosis have a procoagulant-imbalance that possibly plays a role in increasing the risk of cardiovascular disease and progression of fibrosis.

Incidence, predictive factors and clinical significance of development of portal vein thrombosis in cirrhosis: A prospective study

BACKGROUND AND AIMS

The role of portal vein thrombosis (PVT) in the natural history of cirrhosis is controversial. There are few prospective studies validating risk factors for development of PVT. We analysed the incidence, factors associated with PVT development and its influence on cirrhosis decompensations and orthotopic liver transplant (OLT)-free survival.

METHODS

In this prospective observational study between January 2014 and March 2019, 445 consecutive patients with chronic liver disease were screened and finally 241 with cirrhosis included. Factors associated with PVT development and its influence on cirrhosis decompensations and OLT-free survival by time dependent covariate coding were analysed.

RESULTS

Majority of patients belonged to Child-Pugh class A 184 (76.3%) and the average MELD score was 10 ± 5. Previous cirrhosis decompensations occurred in 125 (52.1%), 63 (26.1%) were on NSBB and 59 (27.2%) had undergone banding for bleeding prophylaxis. Median follow-up was 29 (1-58) months. Cumulative incidence of PVT was 3.7% and 7.6% at 1 and 3 years. Previous decompensation of cirrhosis and low platelet counts but not NSBB independently predicted the development of PVT. During follow-up, 82/236 (34.7%) patients developed cirrhosis decompensations. OLT-free survival was 100% and 82.8% at 3 years, with and without PVT respectively. MELD score, but not PVT, independently predicted cirrhosis decompensations (HR 1.14; 95%CI:1.09-1.19) and OLT-free survival (HR 1.16;95%CI:1.11-1.21).

CONCLUSION

Previous decompensations of cirrhosis and thrombocytopenia predict PVT development in cirrhosis suggesting a pathophysiologic role for severity of portal hypertension. PVT development did not independently predict cirrhosis decompensations or lower OLT-free survival.

Hepatocellular Carcinoma Recurrence in HCV Patients Treated with Direct Antiviral Agents

The risk of hepatocellular carcinoma recurrence is universal regardless of the treatment modality applied, and secondary prevention is still an unmet issue even though the elimination of hepatitis C (HCV) with direct antiviral agents (DAAs) was expected to be one of the new options. Unfortunately, the impact of DAAs on hepatocellular carcinoma (HCC) development (de novo and recurrence) is still controversial. Since the first publication on the subject in 2016, almost all groups worldwide have carried out research in this field with hundreds of publications now available. This revision is focused on the impact of DAAs on HCC recurrence and aims to discuss the potential underlying mechanisms and host factors pointing out the time association phenomenon between DAA treatment and HCC recurrence. Moreover, we comment on the methodological issues that could affect the different interpretations of the published results. In conclusion, this is an area of research with potential in the understanding of the impact of factors not previously considered, and may also help change hepatocarcinogenesis tenets, such as the belief that the elimination of HCV should be used as a second prevention treatment.

Prospective Assessment of Liver Function by an Enzymatic Liver Function Test to Estimate Short-Term Survival in Patients with Liver Cirrhosis

BACKGROUND

MELD attempts to objectively predict the risk of mortality of patients with liver cirrhosis and is commonly used to prioritize organ allocation. Despite the usefulness of the MELD, updated metrics could further improve the accuracy of estimates of survival.

AIMS

To assess and compare the prognostic ability of an enzymatic ¹³C-based liver function test (LiMAx) and distinct markers of liver function to predict 3-month mortality of patients with chronic liver failure.

METHODS

We prospectively investigated liver function of 268 chronic liver failure patients without hepatocellular carcinoma. Primary study endpoint was liver-related death within 3 months of follow-up. Prognostic values were calculated using Cox proportional hazards and logistic regression analysis.

RESULTS

The Cox proportional hazard model indicated that LiMAx (p < 0.001) and serum creatinine values (p < 0.001) were the significant parameters independently associated with the risk of liver failure-related death. Logistic regression analysis revealed LiMAx and serum creatinine to be independent predictors of mortality. Areas under the receiver-operating characteristic curves for MELD (0.86 [0.80-0.92]) and for a combined score of LiMAx and serum creatinine (0.83 [0.76-0.90]) were comparable.

CONCLUSIONS

Apart from serum creatinine levels, enzymatic liver function measured by LiMAx was found to be an independent predictor of short-term mortality risk in patients with liver cirrhosis. A risk score combining both determinants allows reliable prediction of short-term prognosis considering actual organ function. Trial Registration Number (German Clinical Trials Register) # DRKS00000614.

Perioperative Thromboelastometry for Adult Living Donor Liver Transplant Recipients with a Tendency to Hypercoagulability: A Prospective Observational Cohort Study

Background

Hypercoagulability can lead to serious thromboembolic events. The aim of this study was to assess the perioperative coagulation status in liver transplant recipients with a tendency to hypercoagulability.

Methods

In a prospective observational study (South African Cochrane Registry 201405000814129), 151 potential liver transplant recipients were screened for thrombophilic factors from October 2014 to June 2017, and 57 potential recipients fulfilled the inclusion criterion of presenting two or more of the following thrombophilic factors: low protein C, low protein S, low anti-thrombin, increased homocystein, increased antiphospholipid IgG/IgM antibodies, increased lupus anticoagulant, and positive Factor V Leiden mutation. Seven patients were excluded from the study because they fulfilled the exclusion criteria of cancelling the liver transplantation, oral anticoagulation, or intraoperative treatment with rFVIIa. Accordingly, 50 patients were included in the final analysis. Thromboelastometry (ROTEM) (EXTEM, INTEM and FIBTEM) and conventional coagulation tests (CCT) were performed preoperatively, during the anhepatic phase, post reperfusion, and on postoperative days (POD) 1, 3 and 7. ROTEM was used to guide blood product transfusion. Heparin was infused (60-180 U/kg/day) postoperatively for 3 days and then was replaced by low-molecular-weight heparin (20 mg/12 h).

Results

FIBTEM MCF significantly increased postoperatively above reference range on POD 7 despite normal fibrinogen plasma concentrations (p < 0.05). Both EXTEM and INTEM demonstrated significant changes with the phases of transplantation (p < 0.05), but with no intra- or postoperative hypercoagulability observed. INTEM CT (reference range, 100-240 s) normalized on POD 3 and 7 (196.1 ± 69.0 and 182.7 ± 63.8 s, respectively), despite prolonged aPTT (59.7 ± 18.7 and 46.4 ± 15.7 s, respectively; reference range, 20-40 s). Hepatic artery thrombosis (HAT) and portal vein thrombosis (PVT) were reported in 12.0% and 2.0%, respectively, mainly after critical care discharge and with high FIBTEM MCF values in 57% on POD 3 and 86% on POD 7. Receiver operating characteristics curve analyses of FIBTEM MCF were significant predictors for thromboembolic events with optimum cut-off, area under the curve and standard error on POD 3 (>23 mm, 0.779 and 0.097; p = 0.004) and POD 7 (>28 mm, 0.706 and 0.089; p = 0.020). Red blood cells (mean ± SD, 8.68 ± 5.81 units) were transfused in 76%, fresh frozen plasma (8.26 ± 4.14 units) in 62%, and cryoprecipitate (12.0 ± 3.68 units) in 28% of recipients. None of the recipients received intraoperative platelet transfusion or any postoperative transfusion. Main transplant indication was hepatitis C infection in 82%. 76% of recipients included in this highly selected patient population showed increased lupus anticoagulant, 2% increased antiphospholipid IgG/IgM antibodies, 20% increased homocysteine, 74% decreased anti-thrombin, 78% decreased protein C, 34% decreased protein S, and 24% a positive Factor V Leiden mutation. Overall 1-year survival was 62%.

Conclusion

A significant postoperative step-wise increase in FIBTEM MCF beyond the reference range was observed despite normal fibrinogen plasma concentrations, and FIBTEM MCF was a predictor for thromboembolic events in this study population, particularly after POD 3 and 7 on surgical wards when CCTs failed to detect this condition. However, the predictive value of FIBTEM MCF for postoperative HAT and PVT needs to be confirmed in a larger patient population. A ROTEM-guided anticoagulation regime needs to be developed and investigated in future studies.

Reversal of hypercoagulability in patients with HCV-related cirrhosis after treatment with direct-acting antivirals

BACKGROUND & AIMS

The long-term impact of sustained virological response (SVR) after direct-acting antivirals (DAAs) on the hypercoagulability associated with HCV cirrhosis is unknown. We longitudinally evaluated the effect of DAAs treatment on cirrhotic coagulopathy.

METHODS

Pro- and anticoagulant factor levels and thrombin generation were assessed in patients with HCV-related cirrhosis at baseline, end of therapy (EOT), at 12, 24 and 48 weeks (W) after EOT.

RESULTS

Fifty-eight patients were enrolled (86% Child's A). SVR was 100%. Median factor VIII activity significantly decreased at EOT, 12 weeks and 24 weeks compared with baseline, whereas protein C significantly increased at 24 weeks and 48 weeks. Cirrhotic patients showed a slight but sustained increase in endogenous thrombin potential (ETP) with a statistically significant difference at EOT, 12 weeks, 24 weeks and 48 weeks compared with baseline. Conversely, thrombomodulin-modified ETP was elevated before treatment and decreased over time to normal levels at 24 weeks and 48 weeks. The ETP ratio decreased slowly at EOT and 12 weeks, and was significantly decreased at 24 weeks and 48 weeks compared with baseline (P < .001 for both comparisons), being not statistically different from ETP ratio measured in healthy controls. Child's B patients showed a significantly higher ETP ratio compared to Child's A at baseline and did not show any significant improvement in ETP ratio through 12 weeks. Two Child's B patients developed PVT with an incidence rate of 1.1% p-yrs (95%CI, 0.18 to 3.58).

CONCLUSIONS

DAAs therapy in HCV-related cirrhotic patients is associated with significant changes in thrombin generation suggesting a reversal of hypercoagulability particularly in Child's A patients.

Perioperative Thromboelastometry for Adult Living Donor Liver Transplant Recipients with a Tendency to Hypercoagulability: A Prospective Observational Cohort Study

Background

Hypercoagulability can lead to serious thromboembolic events. The aim of this study was to assess the perioperative coagulation status in liver transplant recipients with a tendency to hypercoagulability.

Methods

In a prospective observational study (South African Cochrane Registry 201405000814129), 151 potential liver transplant recipients were screened for thrombophilic factors from October 2014 to June 2017, and 57 potential recipients fulfilled the inclusion criterion of presenting two or more of the following thrombophilic factors: low protein C, low protein S, low anti-thrombin, increased homocystein, increased antiphospholipid IgG/IgM antibodies, increased lupus anticoagulant, and positive Factor V Leiden mutation. Seven patients were excluded from the study because they fulfilled the exclusion criteria of cancelling the liver transplantation, oral anticoagulation, or intraoperative treatment with rFVIIa. Accordingly, 50 patients were included in the final analysis. Thromboelastometry (ROTEM) (EXTEM, INTEM and FIBTEM) and conventional coagulation tests (CCT) were performed preoperatively, during the anhepatic phase, post reperfusion, and on postoperative days (POD) 1, 3 and 7. ROTEM was used to guide blood product transfusion. Heparin was infused (60-180 U/kg/day) postoperatively for 3 days and then was replaced by low-molecular-weight heparin (20 mg/12 h).

Results

FIBTEM MCF significantly increased postoperatively above reference range on POD 7 despite normal fibrinogen plasma concentrations (p < 0.05). Both EXTEM and INTEM demonstrated significant changes with the phases of transplantation (p < 0.05), but with no intra- or postoperative hypercoagulability observed. INTEM CT (reference range, 100-240 s) normalized on POD 3 and 7 (196.1 ± 69.0 and 182.7 ± 63.8 s, respectively), despite prolonged aPTT (59.7 ± 18.7 and 46.4 ± 15.7 s, respectively; reference range, 20-40 s). Hepatic artery thrombosis (HAT) and portal vein thrombosis (PVT) were reported in 12.0% and 2.0%, respectively, mainly after critical care discharge and with high FIBTEM MCF values in 57% on POD 3 and 86% on POD 7. Receiver operating characteristics curve analyses of FIBTEM MCF were significant predictors for thromboembolic events with optimum cut-off, area under the curve and standard error on POD 3 (>23 mm, 0.779 and 0.097; p = 0.004) and POD 7 (>28 mm, 0.706 and 0.089; p = 0.020). Red blood cells (mean ± SD, 8.68 ± 5.81 units) were transfused in 76%, fresh frozen plasma (8.26 ± 4.14 units) in 62%, and cryoprecipitate (12.0 ± 3.68 units) in 28% of recipients. None of the recipients received intraoperative platelet transfusion or any postoperative transfusion. Main transplant indication was hepatitis C infection in 82%. 76% of recipients included in this highly selected patient population showed increased lupus anticoagulant, 2% increased antiphospholipid IgG/IgM antibodies, 20% increased homocysteine, 74% decreased anti-thrombin, 78% decreased protein C, 34% decreased protein S, and 24% a positive Factor V Leiden mutation. Overall 1-year survival was 62%.

Conclusion

A significant postoperative step-wise increase in FIBTEM MCF beyond the reference range was observed despite normal fibrinogen plasma concentrations, and FIBTEM MCF was a predictor for thromboembolic events in this study population, particularly after POD 3 and 7 on surgical wards when CCTs failed to detect this condition. However, the predictive value of FIBTEM MCF for postoperative HAT and PVT needs to be confirmed in a larger patient population. A ROTEM-guided anticoagulation regime needs to be developed and investigated in future studies.