EXTEM Maximum Clot Firmness Research Articles

A Randomized Controlled Trial Comparing Effectiveness of Different Fibrinogen Preparations in Restoring Clot Firmness.

Different preparations of fibrinogen concentrate are currently available. Two in vitro studies demonstrated the superiority of FibCLOT (LFB) in increasing clot firmness with respect to RiaSTAP (CSL Behring). The present trial involved a clinical model to test the hypothesis of superiority, with the increase in clot firmness as the primary end point. Forty cardiac surgery patients were randomly allocated to receive a dose of 30 mg/kg FibCLOT or RiaSTAP after protamine administration in the presence of microvascular bleeding and a FIBTEM maximum clot firmness (MCF) <10 mm. Viscoelastic parameters were measured before and after fibrinogen supplementation: FIBTEM MCF, EXTEM MCF, and EXTEM clotting time (CT). The mean increase in FIBTEM MCF was 4 ± 1.2 mm (mean and standard deviation) in the FibCLOT group and 4 ± 1.6 mm in the RiaSTAP group (P = 1.000); the mean decrease in CT was 11. 2 ± 12.2 (mean and standard deviation) seconds in the FibCLOT group and 14. 8 ± 13 seconds in the RiaSTAP group (P = .372). In both groups, fibrinogen supplementation induced a significant (P = .001) increase in the FIBTEM MCF and EXTEM CT. The proportions of patients who did not experience an increase of 4 mm in the RiaSTAP group and the FibCLOT group were not statistically significantly higher (35% vs 20%, respectively, relative risk 2.15, 95% confidence interval 0.52-9.00, P = .288). In contrast to previous in vitro studies, we found that the effect of FibCLOT on MCF and CT was not significantly greater than that of RiaSTAP in cardiac surgery patients. Further studies in other clinical settings are warranted.

Diagnostic Accuracy of Rotational Thromboelastometry for Low-Virulence Periprosthetic Joint Infections: A Pilot Study.

Periprosthetic joint infections (PJIs) are associated with altered coagulation dynamics; therefore, coagulation laboratory studies could be valuable for diagnosing PJI. This study aimed to evaluate the diagnostic role of Rotational Thromboelastometry (ROTEM) in detecting PJIs caused by low-virulence pathogens. A retrospective study was conducted, enrolling 78 patients who underwent exchange arthroplasty due to PJI due to high-virulence pathogens (Group A, n = 16), low-virulence pathogens (Group B, n = 20), or due to aseptic loosening (Group C, n = 20). Preoperative laboratory findings were compared among the three groups. Several ROTEM parameters differed in patients with PJIs caused by low-virulence pathogens, indicating a link between these infections and hypercoagulability. The development of low-virulence PJIs was associated with a higher maximum clot firmness (MCF) (Odds Ratio, 1.12; 95% Confidence Interval, 1.04-1.21; p = 0.001). Additionally, EXTEM MCF was found to have the highest diagnostic accuracy for these infections (Area Under the Curve, 0.841; sensitivity 90.0%; specificity 90.4%), surpassing that of C-reactive protein and the Erythrocyte Sedimentation Rate (p = 0.006 and p = 0.019, respectively). Our findings suggest that ROTEM analysis is a promising method for detecting the altered hemostatic dynamics associated with PJI caused by low-virulence pathogens.

P64: Rotational Thromboelastometry Predictors of Thrombosis in Patients with a Left Ventricular Assist Device

Background: Left ventricular assist devices (LVADs) prolong survival and improve quality of life for patients with advanced heart failure. They are also associated with a variety of complications including thrombotic events. Viscoelastic testing with rotational thromboelastometry (ROTEM) can be used to screen for coagulopathy in a variety of conditions, however, its utility in patients with an LVAD remains unclear. The purpose of this study was to identify ROTEM characteristics associated with thrombosis in hospitalized patients with an LVAD. Methods: This was a single-center, retrospective cohort study of patients with an LVAD who were hospitalized from January 1, 2013, to December 1, 2022. ROTEMs collected during the first 24 hours of hospitalization from patients with confirmed thrombosis were compared to those of patients without thrombosis. Thrombosis was defined as either ischemic stroke, pump thrombosis, or arterial or venous thrombi. Up to five ROTEMs each, consisting of INTEM, EXTEM, and FIBTEM, were collected per patient. Exclusion criteria included ROTEMs collected during the patient’s implant hospitalization or bleeding admission, or patient received a parenteral antithrombotic agent, parenteral antiplatelet agent, reversal agent, or blood product within 48 hours of ROTEM collection. A univariable binary logistic regression model was used to estimate the unadjusted effects of each ROTEM characteristic. Type III Wald Chi-square p-values were reported for each variable. Results: A total of 238 ROTEMs were included in the study with 39 in the thrombosis group and 199 in the non-thrombosis group. At baseline, history of a clotting event (56.4% vs. 37.2%, p=0.03) and age (61.9 + 13.8 vs. 56.6 + 15, p=0.04) were higher in the thrombosis group, while the remaining characteristics were similar between both groups. For the primary outcome, there was no statistically significant difference in EXTEM maximum clot firmness between patients with thrombosis compared to patients without thrombosis (71.6 + 10 vs. 69.7 + 7.9, p=0.20). For secondary outcomes, FIBTEM maximum clot firmness (31.1 + 13.0 vs. 26.8 + 10.6, p=0.03) and FIBTEM amplitude at 20 minutes (30.5 + 12.8 vs. 26.5 + 10.4, p=0.04) were both higher in the thrombosis group compared to the non-thrombosis group. Conclusion: The utility of viscoelastic testing in patients with an LVAD has remained unclear with the limited amount of literature currently available. This study was the first of its class to assess ROTEM characteristics upon hospital admission to screen for coagulopathy in patients with an LVAD. ROTEM characteristics including FIBTEM maximum clot firmness and FIBTEM amplitude at 20 minutes may be utilized as screening tools to identify patients at an increased risk for thrombosis.

The precision of ROTEM EXTEM is decreased in hypocoagulable blood: a prospective observational study

BackgroundThe use of viscoelastic tests is becoming increasingly popular. There is a paucity of validation of the reproducibility of varying coagulation states. Therefore, we aimed to study the coefficient of variation (CV) for the ROTEM EXTEM parameters clotting time (CT), clot formation time (CFT), alpha-angle and maximum clot firmness (MCF) in blood with varying degrees of coagulation strength. The hypothesis was that CV increases in states of hypocoagulability.MethodsCritically ill patients and patients subjected to neurosurgery at a university hospital during three separate periods were included. Each blood sample was tested in eight parallel channels, yielding the CVs for the tested variables. In 25 patients, the blood samples were analysed both at baseline and after dilution with albumin 5%, as well as after being spiked with fibrinogen, simulating weak and strong coagulation.ResultsIn total, 225 unique blood samples were collected from 91 patients. All samples were analysed in eight parallel ROTEM channels, resulting in 1,800 measurements. In hypocoagulable samples, defined as those with values outside the normal reference range, the CV of CT was higher (median (interquartile range)) (6.3% (5.1–9.5)) than for normocoagulable samples (5.1% (3.6–7.5)), p < 0.001. CFT showed no difference (p = 0.14), while the CV of alpha-angle was higher in hypocoagulable samples (3.6% (2.5–4.6)) than in normocoagulable samples (1.1% (0.8–1.6), p < 0.001. The CV of MCF was higher in hypocoagulable samples (1.8% (1.3–2.6)) than in normocoagulable samples (1.2% (0.9–1.7)), p < 0.001. The CV ranges for the different variables were as follows: CT: 1.2%–37%, CFT: 1.7%–30%, alpha-angle: 0.0%–17% and MCF: 0.0%–8.1%.ConclusionsCVs for the EXTEM ROTEM parameters CT, alpha-angle, and MCF increased in hypocoagulable blood compared to blood with normal coagulation, confirming the hypothesis for CT, alpha-angle, and MCF but not for CFT. Furthermore, the CVs for CT and CFT were much higher than those for alpha-angle and MCF. The results demonstrate that EXTEM ROTEM results from patients with weak coagulation should be interpreted with the notion of limited precision and that procoagulative treatment, based only on ROTEM EXTEM, should be given with some caution.

Abstract TP125: Relationships Of Female Sex With Viscoelastic Hemostatic Assay Coagulation Characteristics After Intracerebral Hemorrhage

Introduction: There are described differences in coagulation between females and males. Specifically, female sex is associated with greater platelet activation and stronger clotting characteristics. It is unclear whether there are relevant coagulation differences identifiable between female and male patients suffering from intracerebral hemorrhage (ICH). Hypothesis: Female sex will be associated with stronger clotting characteristics on whole blood viscoelastic hemostatic assay testing. Methods: Spontaneous ICH patients admitted and enrolled into a prospective observational ICH cohort study between 2009-2020 and who received baseline viscoelastic hemostatic assay testing (Rotational Thromboelastometry: ROTEM) were assessed. Patients with prior anticoagulant use, patients receiving hemorrhage control therapies prior to ROTEM, and secondary etiologies of ICH were excluded from the analysis. Female sex was assessed as the primary exposure variable. The following ROTEM clotting parameters were assessed as the outcome: Coagulation Time (CT) and Maximum Clot Firmness (MCF). We assessed relationships of female sex with these separate ROTEM parameters using multivariable linear regression analyses after adjusting for relevant covariates. Results: Of 57 ICH patients included for analyses, mean age was 65 (SD 14.1), 47% were female, and the median ICH volume was 20.6 mL (IQR 10.1-43.3). There were no baseline intergroup sex differences in demographics, age, or ICH characteristics. Female sex was associated with increased EXTEM MCF (ß 0.323, p&lt;0.05), signifying greater clotting strength, after adjusting for age, race, baseline hematoma volume, and ICH location. Female sex was not associated with other ROTEM parameters. Conclusions: We identified that female sex was associated with stronger clotting characteristics on ROTEM viscoelastic testing. Further work is required to clarify the clinical significance of these findings and their potential specific impacts on radiographic, complication, and clinical outcomes after ICH.

605: CORRELATION BETWEEN PLASMA-BASED AND VISCOELASTIC COAGULATION ASSAYS IN PEDIATRIC LIVER FAILURE

Introduction: Liver failure (LF) causes complex coagulation abnormalities leading to bleeding and clotting events. Routinely used plasma-based coagulation (PBC) assays, including international normalized ratio (INR), activated partial thromboplastin time (aPTT), and fibrinogen, have limited bleeding or clotting risk prediction. Whole blood-based viscoelastic assays, including rotational thromboelastometry (ROTEM) and thromboelastography (TEG), are increasingly used to characterize coagulation abnormalities to predict bleeding or clotting events in adults with LF. In this novel study, we aimed to compare PBC assays with ROTEM in pediatric LF as no published data are available yet. Methods: We analyzed a retrospective cohort of children with LF listed for transplant at a tertiary hospital. Samples with simultaneous measurements of PBC assays and ROTEM assays were analyzed. A stratified analysis compared critically ill children admitted to PICU and non-critically ill children from home or acute care before surgery. Results: 63 patients with median age of 38 [IQR 8-149] months, 57% female, 33% in the PICU had 110 simultaneous ROTEM and PBC assays analyzed. About 65% of INR values and 76% of platelet counts were outside the normal range compared to 32% of EXTEM clotting time (CT) (p< 0.001) and 43% of EXTEM maximum clot firmness (MCF) (p< 0.001) respectively. INR showed a weak correlation with EXTEM CT (Spearman’s Coefficient (r)=0.55, p< 0.001) in the entire cohort with no difference between critically ill and not critically ill children. aPTT demonstrated a moderate correlation with INTEM CT (r=0.67, p< 0.001). This correlation was stronger in critically ill children (r=0.78, p< 0.001) compared to the non-critically ill children (r=0.46, p< 0.001). Fibrinogen and platelet count had a strong correlation with FIBTEM and EXTEM MCF (r=0.82 and r=0.80, respectively, p< 0.001) that was similar in the two groups. Conclusions: Children with LF have less frequent coagulation abnormalities on ROTEM compared to PBC assays. INR, traditionally used for prognostication and decision-making, has a weak correlation with EXTEM values on ROTEM regardless of disease severity in children with LF. Determining the association between INR and ROTEM with bleeding or clotting events is needed to ascertain their clinical application.

Tranexamic acid administered during cesarean delivery in high-risk patients: maternal pharmacokinetics, pharmacodynamics, and coagulation status

Tranexamic acid is frequently administered for postpartum hemorrhage. The World Health Organization recommends 1 g intravenous dosing, repeated once after 30 minutes for ongoing bleeding. Understanding the pharmacokinetics and pharmacodynamics of tranexamic acid in patients at high risk of postpartum hemorrhage may enable dosage tailoring for optimal antifibrinolysis with minimal adverse events, such as thrombosis or renal cortical necrosis. This study aimed to report tranexamic acid pharmacokinetics and pharmacodynamics after 1 g intravenous dosing during cesarean delivery in patients at risk of hemorrhage. The primary endpoint was tranexamic acid plasma concentration of >10 μg/mL, known to inhibit 80% of fibrinolysis. In addition, the correlation between patient demographics and rotational thromboelastometry coagulation changes were analyzed. In this prospective study, 20 women aged 18 to 50 years, ≥23 weeks of gestation undergoing cesarean delivery with at least 1 major (placenta previa, suspected placenta accreta spectrum, or active bleeding) or 2 minor (≥2 previous cesarean deliveries, previous postpartum hemorrhage, chorioamnionitis, polyhydramnios, macrosomia, obesity, or suspected placental abruption) risk factors for postpartum hemorrhage were recruited. The exclusion criteria were allergy to tranexamic acid, inherited thrombophilia, previous or current thrombosis, seizure history, renal or liver dysfunction, anticoagulation, or category III fetal heart tracing. Tranexamic acid 1 g was administered after umbilical cord clamping. Blood samples were drawn at 3, 7, 15, and 30 minutes and then at 30-minute intervals up to 5 hours. Plasma concentrations were evaluated as mean (standard error). Serial rotational thromboelastometry was performed and correlated with tranexamic acid plasma concentrations. The median age of participants was 37.5 years (interquartile range, 35.0-39.5), and the median body mass index was 28.6 kg/m2 (interquartile range, 24.9-35.0). The median blood loss (estimated or quantitative) was 1500 mL (interquartile range, 898.5-2076.0). Of note, 9 of 20 (45%) received a transfusion of packed red blood cells. The mean peak tranexamic acid plasma concentration at 3 minutes was 59.8±4.7 μg/mL. All patients had a plasma concentration >10 μg/mL for 1 hour after infusion. Plasma concentration was >10 μg/mL in more than half of the patients at 3 hours and fell <10 μg/mL in all patients at 5 hours. There was a moderate negative correlation between body mass index and the plasma concentration area under the curve (r=-0.49; 95% confidence interval,-0.77 to-0.07; P=.026). Rotational thromboelastometry EXTEM maximum clot firmness had a weak positive correlation with longitudinal plasma concentration (r=0.32; 95% confidence interval, 0.21-0.46; P<.001). EXTEM maximum clot lysis was 0% after infusion in 18 patients (90%), and no patient in the study demonstrated a maximum lysis of >15% at any interval from 3 minutes to 5 hours. There was no significant correlation between EXTEM clot lysis at 30 minutes and longitudinal tranexamic acid plasma concentrations (r=0.10; 95% confidence interval,-0.20 to 0.19; P=.252). After standard 1 g intravenous dosing of tranexamic acid during cesarean delivery in patients at high risk of hemorrhage, a plasma concentration of ≥10 μg/mL was sustained for at least 60 minutes. Plasma tranexamic acid levels correlated inversely with body mass index. The concurrent use of rotational thromboelastometry may demonstrate tranexamic acid's impact on clot firmness but not a hyperfibrinolysis-derived trigger for therapy.

Haemostatic profile of riboflavin-treated apheresis platelet concentrates.

The haemostatic activity of platelet concentrates (PCs) treated with pathogen reduction technology (PRT) remains a subject of debate. Our aim was to investigate the effect of Mirasol PRT on the haemostatic properties of PCs stored in plasma. Untreated and Mirasol-treated platelets stored in plasma and derived from ten split double-dose apheresis PCs were evaluated in vitro on days 1, 3 and 5 post collection for functionality, microparticle procoagulation activity (MPA), endogenous thrombin potential (ETP), and haemostatic profile using rotational thromboelastometry (ROTEM). P-selectin expression was significantly higher in Mirasol-treated platelets compared with untreated counterparts on days 3 and 5 (p=0.003 and p=0.002, respectively). Clot strength, as shown by EXTEM maximum clot firmness (MCF), was significantly lower in the Mirasol-treated platelets at all time points (days 1, 3, 5) than in untreated platelets (p=0.009, p<0.001, p<0.001, respectively). There was a considerable increase in MPA over time (p<0.001) and this was significantly higher in the Mirasol-treated platelets on day 5 (p=0.015). A notable acceleration of decrease in ETP values was observed for Mirasol-treated PCs over time (p<0.001), with significant differences between PRT-treated and untreated PCs on days 3 and 5 (p=0.038 and p=0.019, respectively). Clot strength attenuation was significantly associated with pH reduction (p<0.001, Spearman's rho: 0.84), increased microparticle procoagulant activity (p<0.001, Spearman's rho: -0.75), and with decreased ETP (p<0.032, Spearman's rho: 0.41). Increased platelet activation induced by PRT treatment leads to a decrease in in vitro haemostatic capacity as seen by reduced clot strength and thrombin generation capacity over time. The clinical relevance of this needs to be investigated.

Correlations between rotational thromboelastometry (ROTEM) and standard coagulation tests following viper snakebites.

BackgroundA high prevalence of venom-induced consumption coagulopathy has been reported in individuals with viper snakebites. Rotational thromboelastometry (ROTEM) is a rapid technique that could be advantageous in assessing and monitoring coagulation disorders.PurposeTo explore correlations between ROTEM and standard coagulation tests.Patients and methodsThis prospective observational study was performed among 41 patients with viper envenomation admitted to the Vietnam Poison Control Center from April 2016 to October 2017. Standard coagulation measurements [platelet count, prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen level] and ROTEM indicators [clotting time (CT), amplitude (at set time: 5 and 10 minutes), clot information time (CFT) and maximum clot firmness (MCF) for extrinsic (EXTEM), intrinsic (INTEM), and fibrin based (FIBTEM) ROTEM] were obtained.ResultsFor INTEM, EXTEM, the FIBTEM, proportions of patients with prolonged CT were 34.1%, 63.4%, and 61.0% respectively and the proportions of patients with decreased MCF were 62.2%, 62.2%, and 35.5%, respectively. Moderate correlations were observed between PT and EXTEM CT (r = 0.627), aPTT and INTEM CT (r = 0.626), fibrinogen and FIBTEM MCF (r = 0.723), and platelet count and EXTEM MCF (0.60).ConclusionROTEM indicated a hypocoagulation state in patients with viper snakebite and was moderately correlated with standard coagulation parameters.

Thromboelastometry in Neonates with Respiratory Distress Syndrome: A Pilot Study.

Background: Although respiratory distress syndrome (RDS) constitutes a postnatal risk factor for bleeding and thromboembolic events in neonates, few studies have addressed this issue. We aimed to evaluate the hemostatic profile of neonates with RDS using rotational thromboelastometry (ROTEM). Methods: An observational study was conducted from November 2018 to November 2020 in the NICU of General Hospital of Nikaia “Aghios Panteleimon”. Preterm and term neonates with RDS hospitalized in the NICU were included and EXTEM (tissue factor-triggered extrinsic pathway), INTEM (ellagic acid activated intrinsic pathway), and FIBTEM (with platelet inhibitor cytochalasin D) assays were performed at the onset of the disease. Results: A hypocoagulable profile was noted in neonates with RDS compared to controls, expressed as significant prolongation of EXTEM CT (clotting time) and CFT (clot formation time), lower EXTEM A10 (amplitude at 10 min), MCF (maximum clot firmness), and LI60 (lysis index). Furthermore, prolongation of INTEM CFT and FIBTEM CT, and decreased INTEM and FIBTEM A10 and MCF were found in neonates with RDS. Multivariable logistic regression analysis showed that RDS is an independent factor for the recorded alterations in ROTEM variables. Conclusions: RDS is associated with a hypocoagulable profile and greater hyperfibrinolytic potential compared to healthy neonates.

Serial EXTEM, FIBTEM, and tPA Rotational Thromboelastometry Observations in the Maastricht Intensive Care COVID Cohort-Persistence of Hypercoagulability and Hypofibrinolysis Despite Anticoagulation.

Background: Coronavirus Disease 2019 (COVID-19) patients often present with thromboembolic events. In COVID-19 patients, routine hemostatic assays cannot correctly identify patients at risk for thromboembolic events. Viscoelastic testing with rotational thromboelastometry (ROTEM) might improve the characterization of COVID-19-associated coagulopathy.Objective: To unravel underlying coagulopathy and fibrinolysis over time as measured by serial assessment heparin-independent (FIBTEM and EXTEM) and fibrinolysis illustrating (tissue plasminogen activator; tPA) ROTEM assays.Patients/Methods: Between April 23 and June 12, consecutive adult patients enrolled within the Maastricht Intensive Care COVID (MaastrICCht) cohort were included, and a comprehensive set of clinical, physiological, pharmaceutical, and laboratory variables were collected daily. Twice per week, EXTEM, FIBTEM, and tPA ROTEM were performed. Clotting time (CT), clot formation time (CFT), maximum clot firmness (MCF), lysis onset time (LOT), and lysis time (LT) were determined to assess clot development and breakdown and were compared to routine hemostatic assays.Results: In 36 patients, 96 EXTEM/FIBTEM and 87 tPA ROTEM tests were performed during a 6-week follow-up. CT prolongation was present in 54% of EXTEM measurements, which were not matched by prothrombin time (PT) in 37%. Respectively, 81 and 99% of all EXTEM and FIBTEM MCF values were above the reference range, and median MCF remained elevated during follow-up. The ROTEM fibrinolysis parameters remained prolonged with median LOT consequently >49 min and unmeasurable LT in 56% of measurements, suggesting a severe hypofibrinolytic phenotype.Conclusion: ROTEM tests in COVID-19 ICU patients show hypercoagulability and severe hypofibrinolysis persisting over at least 6 weeks.

O051 / #1169: VISCOELASTIC HEMOSTATIC ASSAYS IN PEDIATRIC EXTRACORPOREAL LIVER SUPPORT

Aims & Objectives: Conflicting data exist on the impact of extracorporeal liver support (ELS) on coagulation profile in patients (pts) with end stage liver disease (ESLD). We previously reported that ESLD pts had mild decrease in fibrinogen and platelets after ELS. Viscoelastic hemostatic assays (VHA) have not been assessed in this population. Methods: Patients with ESLD undergoing ELS per institutional protocol were enrolled. D-dimer, prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (aPTT), fibrinogen level (fib), platelet count (plt), clotting time (CT) and maximum clot firmness (MCF) for ROTEM parameters were assessed pre and post ELS session. Results: 30 pts were enrolled, most common diagnosis was idiopathic fulminant liver failure. 284 ELS sessions were performed, 7% showed significant (≥40%) decrease in fib (group 1). D-dimer pre ELS was higher in group 1 (17±5 vs 12±8 ug/mL FEU, p=0.021) compared to ELS sessions with <40% drop in fib (group 2). Post ELS group 1 showed increased INR (Mean 3.0±1 vs 2.4±0.8, p=<0.05), prolonged aPTT (Mean 68±28 vs 53±20 sec, p=<0.05), HEPTEM CT (Mean 236±75 vs 197±70, p=0.033) and EXTEM CT (Mean 142±94 vs 86±52 sec, p=0.012) as well as decrease in EXTEM MCF (Mean 41±13 vs 49±9, p=0.015) comparing to group 2. FIBTEM MCF and plt were not different in two groups. Some pts in group 1 had prior uncomplicated ELS sessions. Conclusions: ELS rarely may cause significant coagulopathy in pediatric ESLD patients, likely in pts with underlying consumptive state such as disseminated intravascular coagulation. D-dimer and VHA are instrumental in identifying pts at risk.

Combined Use of Rotational Thromboelastometry (Rotem) and Platelet Impedance Aggregometry (Multiplate Analyzer) in Cyanotic and Acyanotic Infants and Children Undergoing Cardiac Surgery With Cardiopulmonary Bypass: Subgroup Analysis of a Randomized Clinical Trial

Few studies have investigated the Multiplate platelet function analyzer in pediatrics. The authors evaluated Multiplate combined with Rotem in terms of guiding platelet transfusion after pediatric cardiac surgery with cardiopulmonary bypass (CPB). The authors further compared coagulation parameters between cyanotic and acyanotic patients. Subgroup analysis of a randomized clinical trial. Tertiary hospital. Patients weighing between seven and 15 kg. None. Rotem and Multiplate tests were performed (1) after anesthesia induction, (2) upon CPB separation, and (3) upon intensive care unit arrival. Among a total of 59 subjects, 9 patients required platelet transfusion. In multivariate linear regression, analysis EXTEM maximum clot firmness upon CPB separation was associated with the volume of transfused platelets (regression coefficient = -0.348 [95% confidence interval -1.006 to -0.028]; p = 0.039). No such association was found for the Multiplate test. Acyanotic and cyanotic heart disease were present in 32 and 27 children, respectively. There were no significant differences between these two groups in terms of platelet count and function. Postoperative blood loss was significantly higher in the cyanotic group compared with the acyanotic arm (p = 0.015; difference [95% confidence interval -2.40 {-4.20 to -0.60}]). There were no differences between groups regarding transfusion of allogeneic blood products. This study showed that Rotem, but not Multiplate results, were associated with platelet transfusion in pediatric cardiac surgery with no intake of platelet inhibitors. The usefulness of combining these tests in platelet transfusion decision-making needs to be evaluated in larger populations.

Rotational thromboelastometry parameters as predicting factors for bleeding in immune thrombocytopenic purpura

Objective/BackgroundPatients with immune thrombocytopenic purpura (ITP) often present with a severe reduction in platelet counts and suffer from an increased risk of bleeding. However, platelet counts do not accurately predict bleeding risk in these patients. MethodsWe thereby conducted a case series prospective study to compare the ability to predict hemorrhage in ITP patients between platelet counts and various rotational thromboelastometry (ROTEM) parameters. ResultsThe inclusion criteria for patients diagnosed with acute, persistent, and chronic ITP were platelet counts of <30 × 109/L and no clinically significant bleeding (grade ≥ 2 according to the WHO Bleeding Scale) at the beginning of the study. After 24 hours of follow-up, of the 45 enrolled patients, 14 (31.1%) experienced clinically significant bleeding. The mean platelet counts of patients with and without clinically significant bleeding were not statistically different (p = .09). However, the mean EXTEM maximum clot firmness (MCF), EXTEM A10, EXTEM area under the curve (AUC), and platelet maximum clot elasticity (MCE) values of the two groups were statistically different (p < .05). There was also a significant difference in IPF values between these two groups (p < .05.) ConclusionResults obtained from this preliminary study demonstrate that ROTEM parameters might be useful in predicting factors for hemorrhage in ITP patients. Future studies with a larger sample size is warranted to confirm our findings, which will allow prompt and effective bleeding management in ITP patients.

The influence of obesity on coagulation in healthy term pregnancy as assessed by rotational thromboelastometry.

Rotational thromboelastometry (ROTEM® ) is a point-of-care coagulation test which has been used to demonstrate hypercoagulability in pregnant populations and obese populations. The aim of this study was to assess the combined effect of pregnancy and obesity on coagulation using ROTEM® in healthy pregnant women of varying body mass indices (BMIs) presenting for elective caesarean delivery. Ethics approval was granted for recruitment of women presenting for elective caesarean delivery. Women with any condition affecting coagulation were excluded. The ROTEM® parameters of extrinsically activated thromboelastometric test / fibrin polymerisation test (EXTEM/FIBTEM) amplitude at five minutes (A5), coagulation time (CT), maximum clot firmness (MCF) and clot formation time (CFT) were compared between three different groups: normal weight, overweight and obese women. One hundred and eighty-five women presenting for elective caesarean delivery met inclusion criteria and were divided into three groups; normal weight (BMI<25kg/m2 , n=86), overweight (BMI 25-29.9kg/m2 , n=54) and obese (BMI≥30kg/m2 , n=45). They had a mean (SD) age of 32.7±5.0years and the median (interquartile range) BMI of 21.9kg/m2 (20.5-23.0), 27.0kg/m2 (26.0-28.5), 36.0kg/m2 (32.2-41.8) for the normal weight, overweight and obese groups respectively. Forty-one (22.2%) women were nulliparous. Across the three groups for FIBTEM A5 (P=0.018), FIBTEM MCF (P=0.032), FIBTEM CFT (P=0.047) and EXTEM MCF (P=0.015) there was evidence of increasing coagulability with increasing BMI. However, following Bonferroni correction, this was no longer significant. There is no association between BMI and ROTEM® parameters in pregnant women presenting for elective caesarean delivery at term.

Hemostatic derangement in leptospirosis: A prospective cross-sectional study.

Context:Coagulation abnormalities have been observed among leptospirosis patients. However, coagulopathy in severe leptospirosis has not been further characterized.Aims:The aim of this study was to evaluate conventional coagulation and rotational thromboelastometry (ROTEM®) parameters in leptospirosis patients.Settings and Design:This prospective cross-sectional comparative study included patients presenting to a tertiary hospital in Sri Lanka with clinically and serologically confirmed leptospirosis (14 severe and 6 mild), dengue (6), sepsis (5), and 6 healthy individuals.Subjects and Methods:Blood samples were collected between the 3rd and 10th days of illness for prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), fibrinogen, lupus anticoagulant, factors VII and VIII, D-dimer, platelet count, and ROTEM.Statistical Analysis Used:ANOVA post hoc comparison using Bonferroni was applied to compare groups.Results:PT and aPTT were prolonged in leptospirosis patients and were corrected with normal plasma. TT was not significantly prolonged in leptospirosis. Fibrinogen was significantly elevated in severe leptospirosis (P = 0.001) and sepsis (P = 0.001) compared with healthy controls and dengue. Thirty percent of leptospirosis patients had thrombocytopenia (17% in mild and 36% in severe). No significant differences were seen in inTEM clotting time (CT) and exTEM CT in leptospirosis when compared to the other three groups. inTEM clot formation time (CFT) and exTEM CFT in dengue were significantly higher compared to severe (P = 0.001) and mild (P = 0.005) leptospirosis. inTEM maximum clot firmness (MCF) (P = 0.001) and exTEM MCF (P = 0.001) were significantly lower in dengue than in leptospirosis. Only one patient with leptospirosis had bleeding manifestations.Conclusions:Abnormalities in conventional coagulation parameters occur in leptospirosis. However, ROTEM parameters in leptospirosis are not significantly altered.

A preliminary study using rotational thromboelastometry to investigate perioperative coagulation changes and to identify hypercoagulability in obese patients undergoing total hip or knee replacement.

Surgery and obesity are known risk factors for thromboembolic events due to the presence of a hypercoagulable state. Rotational thromboelastometry is a viscoelastic assay that can provide a measure of hypercoagulability via a comprehensive assessment of the coagulation process. This prospective study investigates haemostatic changes over time, presence of hypercoagulability and the association between body mass index and thromboelastometry results in patients undergoing major orthopaedic surgery. Fifty adult patients undergoing total hip or knee replacement surgery had serial thromboelastometry measures performed prior to and following surgery, and on postoperative days 1 and 3. A hypercoagulable state, defined by an ExTEM maximum clot firmness G score ≥11 dyne/cm2, was present in 28% of the patients at baseline. The mean ExTEM maximum clot firmness G score increased by an average of three units from 10 (95% confidence interval (CI) 9–11) dyne/cm2 at baseline to 13 (95% CI 13–14) dyne/cm2 on postoperative day 3, with 85% of patients having a G score ≥11 dyne/cm2. A decrease in ExTEM and InTEM clot formation time and an increase in ExTEM, InTEM and FibTEM clot amplitude at 10 minutes, alpha angle and maximum clot firmness were observed by postoperative day 3 ( P &lt; 0.001). There was no significant difference in the mean thromboelastometry values between patients with a body mass index &lt;35 kg/m2or ≥35 kg/m2. Although a modest association between body mass index and the ExTEM maximum clot firmness G score was observed with exploratory data analysis, further study is required in a large cohort to test the effects of confounders, validate these findings, and determine their clinical importance.

A Comparative Study of SEER Sonorheometry Versus Standard Coagulation Tests, Rotational Thromboelastometry, and Multiple Electrode Aggregometry in Cardiac Surgery

Coagulation point-of-care tests for the diagnosis and management of bleeding commonly are used in cardiac surgery. Recently, a new viscoelastic point-of-care device, Quantra (HemoSonics, Charlottesville, VA), which is based on sonic estimation of elasticity via resonance sonorheometry, entered the market. Prior studies have compared the Quantra parameters with conventional coagulation tests and thromboelastography or rotational thromboelastography, but no study has assessed the correlation of the platelet-derived Quantra parameter platelet contribution to stiffness (PCS) with platelet function assays. The present study compared the Quantra-derived coagulation parameters with conventional coagulation tests, rotational thromboelastography-derived parameters, and platelet function measured using multiplate aggregometry. Prospective cohort study. University research hospital. The study comprised 30 cardiac surgery patients before and after cardiopulmonary bypass. None. Quantra clot stiffness showed a very strong correlation with the EXTEM maximum clot firmness before and after cardiopulmonary bypass and in the overall samples (r values 0.94-0.96). Quantra fibrinogen contribution to stiffness was compared with the corresponding FIBTEM and Clauss fibrinogen levels, which also showed a strong level of correlation (r values between 0.74 and 0.87). Quantra PCS strongly correlated with platelet count (r = 0.71) in the overall samples and moderately with adenosine diphosphate-dependent platelet function (r = 0.67). In a multivariable model, both the adenosine diphosphate test value and the platelet count remained independently associated with Quantra PCS. Fibrinogen-dependent clot stiffness properties are well-reflected by the Quantra fibrinogen contribution to stiffness parameter, and PCS incorporates platelet count and function.

Hypocoagulability and Platelet Dysfunction Are Exacerbated by Synthetic Colloids in a Canine Hemorrhagic Shock Model.

Background: Hemorrhagic shock and volume replacement can alter coagulation. Synthetic colloids, hydroxyethyl starch (HES), and gelatin, may enhance hypocoagulability. Our primary objective was to describe the effect of four fluid products on coagulation in canine hemorrhagic shock. Our secondary objective was to compare measurements of coagulation during shock to baseline in all dogs.Methods: Anesthetized greyhounds subjected to atraumatic hemorrhage for 60 min were administered 20 mL kg−1 of either fresh whole blood (FWB), 6% HES 130/0.4, 4% succinylated gelatin (GELO), or 80 mL kg−1 of isotonic crystalloid over 20 min (n = 6 per group). Platelet closure time (PCT), rotational thromboelastometry (ROTEM) and plasma coagulation assays were measured at baseline, end of hemorrhage (shock), and 40 (T60), and 160 (T180) min after study fluid. ROTEM parameters included clotting time (CT), clot formation time (CFT), alpha angle, maximum clot firmness (MCF), lysis index at 60 min (LI60), and thrombodynamic potential index (TPI) for INTEM, EXTEM, FIBTEM (MCF only), and APTEM (LI60 only) profiles. Plasma coagulation assays included prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen concentration and activities of factor VII (FVII), factor VIII (FVIII), and von Willebrand Factor antigen (vWF). Between-group differences were tested using linear mixed models with post-hoc between-group comparisons (Bonferroni-Holm corrected). Differences between baseline and shock were tested using paired t-tests. Significance was set at P < 0.05.Results: GELO showed longer PCT at T60, compared with FWB and CRYST, and at T180, compared with all other groups. HES showed longer EXTEM CT at T60, compared with all other groups. HES showed lower INTEM and EXTEM MCF at T60 and lower INTEM MCF at T180, compared with FWB. Some plasma coagulation assays showed greater hypocoagulability with HES. Comparing shock to baseline, EXTEM CT, INTEM CFT, EXTEM CFT, PT, and FVIII significantly increased and PCT, INTEM CT, INTEM MCF, EXTEM MCF, EXTEM LI60, EXTEM TPI, FIBTEM MCF, APTT, fibrinogen, FVII, and vWF significantly decreased.Conclusions: In dogs with hemorrhagic shock, volume replacement with GELO caused mild platelet dysfunction and HES was associated with coagulation changes consistent with hypocoagulability, beyond effects of hemodilution. Shock alone produced some evidence of hypocoagulability.

Characteristics of hyperfibrinolysis in dogs and cats demonstrated by rotational thromboelastometry (ROTEM)

Hyperfibrinolysis (HFL) is a pathophysiological mechanism that has not been described in dogs or cats extensively. The aim of this study was to describe rotational thromboelastometry (ROTEM) parameters and underlying diagnosis in dogs and cats with HFL and evaluate association with bleeding diathesis. The ROTEM database was retrospectively searched for EXTEM (ROTEM activated with proprietary tissue factor) tracings with maximum lysis at 60min ≥15%. Concurrent ROTEM and plasma coagulation tests, thrombocyte number, diagnosis and survival to hospital discharge were extracted from medical records. Analysis of differences between dogs and cats and of factors associated with bleeding, fulminant HFL (clot breakdown within 30min) and survival to hospital discharge were performed.Hyperfibrinolysis was detected in eight cats presenting with haemoabdomen or haemothorax (n=4/8, 50%) and trauma (n=3/8, 38%) and in 36 dogs with angiostrongylosis (n=12, 33%), neoplasia (n=7, 19%), liver disease (n=4, 11%) and others including apparently healthy dogs (n=3, 8%). Hyperfibrinolysis was associated with prolonged EXTEM and APTEM (EXTEM with added apoprotein for inhibition of HFL) clotting time and decreased FIBTEM (EXTEM with added cytochalasin D for inhibition of thrombocytes) maximum clot firmness (MCF) in dogs and cats and with decreased EXTEM MCF in dogs. Bleeding dogs had significantly hypocoagulable EXTEM tracings. Fulminant HFL was associated with severe hypofibrinogenaemia in dogs (P=0.005) and was not associated with survival to hospital discharge. Evidence of HFL was demonstrated in dogs and cats with bleeding, trauma, parasitic and neoplastic disease. HFL is associated with late and weak clot formation.