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

Intrinsic or Nonintrinsic End-stage Liver Disease and Its Association With Thromboelastography-based Coagulation States in Patients Undergoing Liver Transplantation: A Retrospective Cohort Study

OBJECTIVES

Perioperative coagulation management in liver transplantation recipients is challenging. Viscoelastic testing with rotational thromboelastography (TEG) can help quantify hemostatic profiles. The current work aimed to investigate whether the etiology of end-stage liver disease, pretransplant disease severity, or pretransplant thrombotic or bleeding complications are associated with specific TEG patterns.

DESIGN

Retrospective cohort study.

SETTING

Single quaternary care hospital.

PARTICIPANTS

A total of 1,078 adult liver transplant patients.

INTERVENTIONS

The primary exposure was the etiology of end-stage liver disease classified as either intrinsic or nonintrinsic (eg, biliary obstruction or cardiovascular). Secondary exposures were patients' preoperative Model for End-Stage Liver Disease (MELD) score, Child-Pugh class, presence of major preoperative thrombotic complications, and major bleeding complications.

MEASUREMENTS AND MAIN RESULTS

Patients with intrinsic liver disease (84%) showed higher odds of hypocoagulable (odds ratio [OR]: 3.70, 95% confidence interval [CI]: 1.94-7.07, p < 0.0001) and mixed TEG patterns (OR: 4.59, 95% CI: 2.07-10.16, p = 0.0002) compared with those with nonintrinsic disease. Increasing MELD scores correlated with higher odds of hypocoagulable (OR: 1.14, 95% CI: 1.08-1.19, p < 0.0001) and mixed TEG patterns (OR: 1.08, 95% CI: 1.03-1.14, p = 0.0036). Child-Pugh class C was associated with higher odds of hypocoagulable (OR: 8.55, 95% CI: 3.26-22.42, p < 0.0001) and mixed patterns (OR: 12.48, 95% CI: 3.89-40.03, p < 0.0001). Major preoperative thrombotic complications were not associated with specific TEG patterns, although an interaction with liver disease severity was observed.

CONCLUSIONS

Liver transplantation candidates with intrinsic liver disease tend to exhibit hypocoagulable TEG patterns, while nonintrinsic disease is associated with hypercoagulability. Increasing end-stage liver disease severity, as evidenced by increasing MELD scores and higher Child-Pugh classification, was also associated with hypocoagulable TEG patterns.

TEG® 6s coagulation testing with a novel heparin neutralization cartridge: Technical validation and determination of normal reference ranges

OBJECTIVES

We sought to establish normal reference ranges (NRRs) for a novel TEG 6s cartridge (TEG 6s Citrated: K, KH, RTH, FFH [Global Hemostasis]) (Haemonetics Corporation, Boston, MA, US).

METHODS

Healthy volunteers (≥18 years of age) included in this single-arm study provided single samples of whole blood. Primary end points included TEG parameters in the citrated kaolin (CK), CK with heparinase (CKH), RapidTEG with heparinase (CRTH), and functional fibrinogen with heparinase (CFFH) assays.

RESULTS

Evaluable data were contributed by 164 volunteers (48.8% female; 62% White/Caucasian). The following NRRs were established: CK maximum amplitude (MA), 51.0 to 67.6 mm; CKH-MA, 51.8 to 67.9 mm; CRTH-MA, 53.0 to 68.9 mm; CFFH-MA, 15.3 to 34.4 mm; CK reaction time, 5.0 to 9.1 minutes; CKH reaction time, 4.9 to 9.4 minutes; CKH lysis 30 minutes after MA, 0% to 3.2%. Duplicate measurements demonstrated high reproducibility. CFFH-MA correlated with Clauss fibrinogen concentration (Pearson correlation coefficient, 0.74). Laboratory-based studies demonstrated maintenance of the relationship between CFFH-MA and fibrinogen up to 1344 mg/dL (hyperfibrinogenemic samples) and acceptability of heparin neutralization up to concentrations of low molecular weight and unfractionated heparin of 1.3 IU/mL and 5 IU/mL, respectively.

CONCLUSIONS

This study established NRRs for the Global Hemostasis cartridge and serves as a proof of concept for the validity of results obtained using this cartridge.

Evaluation of coagulopathy in cirrhotic patients: A scoping review of the utility of viscoelastic testing

BACKGROUND

Cirrhosis causes significant coagulopathy. Traditional coagulation tests may not accurately measure coagulopathy in well-compensated patients with cirrhosis. Viscoelastic tests are functional tests that may better assess coagulopathy in cirrhotic patients.

METHODS

We searched PubMed, ScienceDirect, Google Scholar, and grey literature using terms meaning viscoelastic testing and cirrhosis. After reviewing over 500 titles and abstracts, 40 full-text papers met inclusion criteria.

RESULTS

Twenty-two papers found viscoelastic testing was a better indicator of baseline coagulation than traditional testing in cirrhosis. Nineteen additional papers evaluated the utility of peri-procedural viscoelastic testing and found they led to a reduction in blood product administration without increasing risk of hemorrhage, thrombotic events, or other complications.

CONCLUSIONS

The usage of viscoelastic testing in patients with cirrhosis allows for better assessment of coagulopathy, resulting in improved outcomes. Educating physicians to optimize care of this high-risk group is necessary to further improve their treatment.

Trends and predictions of perioperative transfusion and venous thromboembolism in hepatectomy using a North American Registry

BACKGROUND

Studies indicate a link between allogeneic blood transfusion and venous thromboembolism (VTE) post-major surgery. Analyzing trends and predictors of these outcomes after hepatectomy can inform risk management.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was used for a retrospective analysis. Primary outcomes were perioperative red blood cell (RBC) transfusion and VTE events within 30 days of hepatectomy. Seven-year trends and predictors were evaluated.

RESULTS

Among 29,131 hepatectomy patients, transfusion rates showed no statistically significant decreasing trends (p = .122) from 2014 to 2020 (18.13%-16.71%), while VTE rates showed a downward trend over the 7 years (p = .021); 17.2% received RBC transfusion, with higher rates in surgeries lasting ≥282 min (median: 220 min). Calculated RBC mass [hematocrit (%) × body weight (kg) × 10-5  × 70/ √ (body mass index/22)] at or below 1.5 L substantially increased transfusion odds. VTE was reported postoperatively in 2.6% of cases more frequently in longer cases involving transfusions. The adjusted odds ratio (aOR) of VTE escalated from the shortest operative time to the longest (3.17; 95% confidence interval [CI], 2.37-4.22). The adjusted odds of VTE doubled for transfused patients compared to non-transfused patients (aOR, 2.19; 95% CI, 1.86-2.57).

CONCLUSIONS

Rates of RBC transfusion and VTE rates hepatectomy have minimally changed in the recent years. VTE prevention is challenging in extended surgeries at increased risk of bleeding and RBC transfusions. Patient-level data on coagulation and thromboprophylaxis can potentially refine risk assessment for postoperative VTE.

Patient Blood Management in Liver Transplant—A Concise Review

Transfusion of blood products in orthotopic liver transplantation (OLT) significantly increases post-transplant morbidity and mortality and is associated with reduced graft survival. Based on these results, an active effort to prevent and minimize blood transfusion is required. Patient blood management is a revolutionary approach defined as a patient-centered, systematic, evidence-based approach to improve patient outcomes by managing and preserving a patient’s own blood while promoting patient safety and empowerment. This approach is based on three pillars of treatment: (1) detecting and correcting anemia and thrombocytopenia, (2) minimizing iatrogenic blood loss, detecting, and correcting coagulopathy, and (3) harnessing and increasing anemia tolerance. This review emphasizes the importance of the three-pillar nine-field matrix of patient blood management to improve patient outcomes in liver transplant recipients.

Elevated levels of soluble glycoprotein V - The plasma marker of platelet activation by thrombin in patients with early stage primary biliary cholangitis (PBC)

PURPOSE

There is a growing body of evidence for a prothrombotic tendency in patients with primary biliary cholangitis (PBC). The aim of the study was to evaluate coagulation disorders in patients with early stage PBC compared to healthy controls and evaluation of their relationship with clinical data, with particular emphasis on minimal hepatic encephalopathy (MHE).

PATIENTS AND METHODS

Fifty-one participants (PBC group - 38 patients, all patients but one Child-Pugh A; control group - 13 healthy controls) were included in our prospective, single center study. We assessed the plasma levels of sGPV, plasma procoagulant phospholipids (PPL) and rotational thromboelastometry (ROTEM) profiles in all study participants. Porto-systemic encephalopathy syndrome test was used to assess MHE.

RESULTS

The sGPV levels were higher in the PBC group compared to the controls: 36.07 ​± ​11.32 ​ng/mL vs 27.04 ​± ​11.72 ​ng/mL, p ​= ​0.031. The PPL level was lower in the PBC group compared to controls resulting in increased clotting time in a factor Xa-based coagulation assay: 54.65 (47.83-58.83) sec. vs 45.90 (43.3-50.5) sec., p ​= ​0.0065. PPL levels were correlated with platelet count (rho ​= ​-0.46, p ​= ​0.001). ROTEM parameters did not differ significantly between groups. Coagulation parameters did not differ significantly between patients with and without MHE.

CONCLUSIONS

We have showed increased levels of sGPV - a plasma marker of platelet activation by thrombin in patients with early stage PBC compared to healthy controls. We found no relationship between the coagulation disorders and the occurrence of MHE. The PPL level was lower in the PBC group.

Peri-operative thrombophilia in patients undergoing liver resection for colorectal metastases

BACKGROUND

Routine chemical venous thromboembolism (VTE) prophylaxis for liver surgery remains controversial, and often delayed post-operatively due to perceived bleeding risk. This study asked whether patients undergoing hepatectomy for colorectal metastases (CRM) were at risk from VTE pre-operatively, and the impact of hepatectomy on that risk.

METHODS

Single-centre prospective observational cohort study of patients undergoing open hepatectomy for CRM, comparing pre-, peri- and post-operative haemostatic variables.

RESULTS

Of 336 hepatectomies performed October 2017-December 2019, 60 resections in 57 patients were recruited. There were 28 (46.7%) major resections, with median (interquartile range [IQR]) blood loss 150.0 (76.3-263.7) mls, no blood transfusions, post-operative VTE events or deaths. Patients were prothrombotic pre-operatively (high median factor VIIIC and increased thrombin generation velocity index), an effect exacerbated post-hepatectomy. Major hepatectomies had a significantly greater median drop in Protein C, rise in Factor VIIIC and von Willebrand Factor, versus minor resections (p = 0.001, 0.005, 0.001 respectively). Patients with parenchymal transection times greater than median (40 min), had significantly increased median (IQR) PMBC-TFmRNA expression [1.65(0.93-2.70)2ddCt], versus quicker transections [0.99(0.69-1.28)2ddCt, p = 0.020].

CONCLUSIONS

Patients with CRM are prothrombotic pre-operatively, an effect exacerbated by hepatectomy, particularly longer, complex resections, suggesting chemical thromboprophylaxis be considered early in the patient pathway.

Haemostasis patterns in patients with acute-on-chronic liver failure and acute decompensation of cirrhosis including thromboelastometric tests with and without the addition of Protac: a pilot study

BACKGROUND

Thromboelastometry is considered the best method to assesses hemostasis in liver disease. Diagnostic performance could be improved by adding protein C activators such as thrombomodulin or Protac®. We assessed changes in ROTEM parameters after the addition of Protac® in patients with acute-on-chronic liver failure (ACLF), acute decompensation (AD), and healthy individuals (HI) to define different hemostasis patterns, considering standard and velocity ROTEM parameters, and assess whether Protac® can improve the definition of the pattern.

METHODS

Pre-test, we investigated whether diluted EXTEM reagent improved the effect of Protac® on the clotting time (CT)-ratio with and without Protac®. Ten ACLF and 20 AD patients and 21 HI were included in the main study.

RESULTS

Standard EXTEM was used in the main study. INTEM CFT, INTEM A5 (inverse), and INTEM TPI (inverse) were the parameters that best differentiated liver disease from HI (ROC AUC, 0.921, 0.906, and 0.928, respectively; all P-values < 0.001). Combining INTEM CFT with EXTEM LI60-ratio only slightly improved the diagnostic performance (ROC AUC, 0.948; P < 0.001). EXTEM LI60 and INTEM maxV-t were the parameters that best differentiated between ACLF and AD patients (ROC AUC, 0.743, P = 0.033; and 0.723, P = 0.050; respectively). Combining EXTEM LI60 + INTEM maxV-t moderately improved the diagnostic performance (ROC AUC, 0.81, P < 0.001).

CONCLUSIONS

ROTEM velocity, fibrinolysis parameters and the indices calculated improve the diagnosis in combination with standard parameters (e.g., CFT and A5). Ratios calculated with and without Protac® (e.g., EXTEM LI60-ratio) only slightly increased the diagnostic performance in discriminating hemostasis patterns.

Thromboelastography-Guided Therapy Enhances Patient Blood Management in Cirrhotic Patients: A Meta-analysis Based on Randomized Controlled Trials

Patients with cirrhosis often have abnormal hemostasis, with increased risk of hemorrhage and thrombosis. Thromboelastography provides a rapid assessment of the coagulation status and can guide product transfusions in adult patients with cirrhosis. This study aimed to determine whether the use of thromboelastography in adult patients with cirrhosis decreases blood product use and impacts adverse events or mortality compared with standard practice. A registered (PROSPERO CRD42020192458) systematic review and meta-analysis was conducted for randomized controlled trials (RCTs) comparing thromboelastography-guided hemostatic management versus standard practice (control). Co-primary outcomes were the number of transfused platelet units and fresh frozen plasma (FFP) units. Secondary outcomes were mortality, adverse events, utilization of individual blood products, blood loss or excessive bleeding events, hospital/intensive care unit stay, and liver transplant/intervention outcomes. The search identified 260 articles, with five RCTs included in the meta-analysis. Platelet use was five times lower with thromboelastography versus the control, with a relative risk of 0.17 (95% confidence interval [CI]: [0.03–0.90]; p = 0.04), but FFP use did not differ significantly. Thromboelastography was associated with less blood product (p < 0.001), FFP + platelets (p < 0.001), and cryoprecipitate (p < 0.001) use. No differences were reported in bleeding rates or longer term mortality between groups, with the thromboelastography group having lower mortality at 7 days versus the control (relative risk [95% CI] = 0.52 [0.30–0.91]; p = 0.02). Thromboelastography-guided therapy in patients with cirrhosis enhances patient blood management by reducing use of blood products without increasing complications.

Thromboelastography-Guided Therapy Enhances Patient Blood Management in Cirrhotic Patients: A Meta-analysis Based on Randomized Controlled Trials

Patients with cirrhosis often have abnormal hemostasis, with increased risk of hemorrhage and thrombosis. Thromboelastography provides a rapid assessment of the coagulation status and can guide product transfusions in adult patients with cirrhosis. This study aimed to determine whether the use of thromboelastography in adult patients with cirrhosis decreases blood product use and impacts adverse events or mortality compared with standard practice. A registered (PROSPERO CRD42020192458) systematic review and meta-analysis was conducted for randomized controlled trials (RCTs) comparing thromboelastography-guided hemostatic management versus standard practice (control). Co-primary outcomes were the number of transfused platelet units and fresh frozen plasma (FFP) units. Secondary outcomes were mortality, adverse events, utilization of individual blood products, blood loss or excessive bleeding events, hospital/intensive care unit stay, and liver transplant/intervention outcomes. The search identified 260 articles, with five RCTs included in the meta-analysis. Platelet use was five times lower with thromboelastography versus the control, with a relative risk of 0.17 (95% confidence interval [CI]: [0.03-0.90]; p = 0.04), but FFP use did not differ significantly. Thromboelastography was associated with less blood product (p < 0.001), FFP + platelets (p < 0.001), and cryoprecipitate (p < 0.001) use. No differences were reported in bleeding rates or longer term mortality between groups, with the thromboelastography group having lower mortality at 7 days versus the control (relative risk [95% CI] = 0.52 [0.30-0.91]; p = 0.02). Thromboelastography-guided therapy in patients with cirrhosis enhances patient blood management by reducing use of blood products without increasing complications.

Thromboelastography-Guided Therapy Enhances Patient Blood Management in Cirrhotic Patients: A Meta-analysis Based on Randomized Controlled Trials

Patients with cirrhosis often have abnormal hemostasis, with increased risk of hemorrhage and thrombosis. Thromboelastography provides a rapid assessment of the coagulation status and can guide product transfusions in adult patients with cirrhosis. This study aimed to determine whether the use of thromboelastography in adult patients with cirrhosis decreases blood product use and impacts adverse events or mortality compared with standard practice. A registered (PROSPERO CRD42020192458) systematic review and meta-analysis was conducted for randomized controlled trials (RCTs) comparing thromboelastography-guided hemostatic management versus standard practice (control). Co-primary outcomes were the number of transfused platelet units and fresh frozen plasma (FFP) units. Secondary outcomes were mortality, adverse events, utilization of individual blood products, blood loss or excessive bleeding events, hospital/intensive care unit stay, and liver transplant/intervention outcomes. The search identified 260 articles, with five RCTs included in the meta-analysis. Platelet use was five times lower with thromboelastography versus the control, with a relative risk of 0.17 (95% confidence interval [CI]: [0.03-0.90]; p = 0.04), but FFP use did not differ significantly. Thromboelastography was associated with less blood product (p < 0.001), FFP + platelets (p < 0.001), and cryoprecipitate (p < 0.001) use. No differences were reported in bleeding rates or longer term mortality between groups, with the thromboelastography group having lower mortality at 7 days versus the control (relative risk [95% CI] = 0.52 [0.30-0.91]; p = 0.02). Thromboelastography-guided therapy in patients with cirrhosis enhances patient blood management by reducing use of blood products without increasing complications.

TEG® and ROTEM® Traces: Clinical Applications of Viscoelastic Coagulation Monitoring in Neonatal Intensive Care Unit

The concentration of the majority of hemostatic proteins differs considerably in early life, especially in neonates compared to adulthood. Knowledge of the concept of developmental hemostasis is an essential prerequisite for the proper interpretation of conventional coagulation tests (CCT) and is critical to ensure the optimal diagnosis and treatment of hemorrhagic and thrombotic diseases in neonatal age. Viscoelastic tests (VETs) provide a point-of-care, real-time, global, and dynamic assessment of the mechanical properties of the coagulation system with the examination of both cellular and plasma protein contributions to the initiation, formation, and lysis of clots. In this work, we provide a narrative review of the basic principles of VETs and summarize current evidence regarding the two most studied point-of-care VETs, thromboelastography (TEG®) and rotational thromboelastometry (ROTEM®), in the field of neonatal care. A literature analysis shows that viscoelastic hemostatic monitoring appears to be a useful additive technique to CCT, allowing targeted therapy to be delivered quickly. These tools may allow researchers to determine the neonatal coagulation profile and detect neonatal patients at risk for postoperative bleeding, coagulation abnormalities in neonatal sepsis, and other bleeding events in a timely manner, guiding transfusion therapies using the goal-oriented transfusion algorithm. However, diagnosis and treatment algorithms incorporating VETs for neonatal patients in a variety of clinical situations should be developed and applied to improve clinical outcomes. Further studies should be performed to make routinary diagnostic and therapeutic application possible for the neonatal population.