Clot Lysis Index Research Articles

Point-of-care viscoelastic coagulation monitoring device shows promise for informing resuscitation strategies in a canine hemorrhagic shock model.

To use a point-of-care viscoelastic coagulation monitoring device (VCM-Vet; Entegrion) and traditional tests to assess hemostatic changes during hemorrhagic shock in dogs. 8 healthy, purpose-bred Beagles were enrolled in a hemorrhagic shock model conducted from September through December 2021. Dogs were anesthetized, had baseline hemostatic variables measured after blood pressure was stabilized at 70 to 80 mm Hg for 10 minutes (T1), had blood withdrawn from a jugular vein to achieve a mean blood pressure of 40 ± 5 mm Hg for 10 minutes (T2), were resuscitated with 100% shed blood, and then had hemostatic variables evaluated 10 minutes later (T3). At each time point, hemostatic variables were measured with traditional tests (Hct, WBC count, platelet count, mean platelet volume, prothrombin time, activated partial thromboplastin time [aPTT], and concentrations of fibrinogen, antithrombin, and D-dimer) and the VCM-Vet device (clot time, clot formation time, α-angle, maximum clot formation, amplitude at 10 minutes [A10], amplitude at 20 minutes [A20], clot lysis index at 30 minutes [LI30], and clot lysis index at 45 minutes [LI45]). All dogs survived without complication. At T2 and T3 (vs T1), samples had significantly higher coagulability (increased median α-angle, A10, and A20) and fibrinolysis (decreased median LI30 and LI45) and significantly longer aPTT; however, all values remained within reference limits. The use of VCM-Vet helped identify complex hemostatic disturbances in dogs with hemorrhagic shock. The use of VCM-Vet shows promise in aiding veterinarians in optimizing resuscitation strategies based on real-time clotting data.

Hemostatic Status of Neonates with Perinatal Hypoxia, Studied via NATEM in Cord Blood Samples.

Perinatal hypoxia may result in coagulation dysfunction. Diminished blood flow or oxygen to the fetus/neonate during the perinatal period can cause bone marrow and liver function impairment, leading to thrombocytopenia, impaired synthesis of clotting and fibrinolytic factors, and increased destruction of platelets in the small blood vessels. The goal of the present study was to evaluate the hemostatic status of newborns with perinatal hypoxia via the non-activated thromboelastometry (NATEM) assay in cord blood samples. 134 hypoxic neonates born in our maternity unit over a 1.5-year period were enrolled in this observational cohort study, and 189 healthy neonates served as the control group. Participation in the study was voluntary and parents signed informed consent prior to recruitment. Demographic and clinical data were recorded on admission, and the NATEM method was performed on cord blood samples. The following NATEM values were evaluated: clotting time (CT), alpha angle (α-angle), clot formation time (CFT), clot amplitude at 5 and 10 min. (A5, A10), maximum clot firmness (MCF), clot lysis index at 60 min. after CT (LI60), and maximum clot elasticity (MCE). Statistical analysis was conducted utilizing the SAS for Windows 9.4 software platform. Neonates with perinatal hypoxia exhibited decreased fibrinolytic potential in comparison to healthy neonates, as indicated by increased LI60, and this difference was statistically significant (LΙ60: 94 (92-96) Vs 93 (91-95), p value = 0.0001). There were no statistically significant differences noted among the remaining NATEM variables. Our findings indicate decreased fibrinolytic potential in hypoxic neonates in comparison to healthy neonates, suggesting that NATEM could serve as an effective tool for promptly identifying hemostasis dysfunction in this group of neonates.

Viscoelastic coagulation monitoring parameters in cats with acute arterial thromboembolism.

Hypercoagulability has been documented in cats with cardiac disease. However, hemostatic parameters, including viscoelastic coagulation monitoring (VCM) have not been reported in cats with arterial thromboembolism (ATE). Compare VCM parameters in cats with acute cardiogenic ATE and in control cats. Sixteen cats with ATE and 30 control cats. Multicenter university-based prospective study. Cardiogenic ATE was diagnosed based on physical examination and by ultrasonographically-diagnosed left atrial enlargement. Viscoelastic coagulation monitor analysis, CBC, serum biochemistry profile and coagulation profile were performed at admission in cats with ATE. Analysis from healthy control cats was performed using blood collected by direct venipuncture. Our objective was comparison of VCM parameters clot time (CT), clot formation time (CFT), alpha angle (Angle), maximum clot formation (MCF), amplitude at 10 and 20 minutes (A10 and A20, respectively) and clot lysis index at 30 and 45 minutes (LI30 and LI45, respectively) between ATE and control cats. Cats with ATE had a decreased angle compared to control cats, with a median (range) of 43° (30-48°) compared to 47° (14-59°; P = .01). The parameters A10, A20 and MCF were decreased in ATE cats compared to control cats with a median (range) of 19 units (8-32) compared to 22 units (6-38), 24.5 units (11-40) compared to 29 units (10-47) and 29.5 units (13-44) compared to 33.5 units (14-53), respectively (P = .01, .01 and .01, respectively). The parameters CT, CFT, LI30 and LI45 were similar between groups (P = .22, .09, .62 and .34, respectively). Cats with cardiogenic ATE cats have VCM parameters consistent with hypocoagulability compared with healthy cats.

The use of thromboelastography and the functional tests with double local hypoxia of the upper limb to assess the risk of thromboembolism in patients undergoing surgery

The use of thromboelastography and the functional tests with double local hypoxia of the upper limb to assess the risk of thromboembolism in patients undergoing surgery

Elevated Pre- and Postoperative ROTEM™ Clot Lysis Indices Indicate Reduced Clot Retraction and Increased Mortality in Patients Undergoing Liver Transplantation.

Background: The ROTEM™ clot lysis index, describing the decrease in firmness of a clot with time, predicts mortality in various settings. The variability of the clot lysis index in surgical procedures and the involved pathophysiological mechanisms are unknown. We therefore compared pre- and postoperative clot lysis indices in liver transplantation (LTX) procedures, determined the eventual association with mortality, and investigated the mechanisms underlying decreased clot lysis index using inhibitors of fibrinolysis and clot retraction, respectively. Methods: In this retrospective cohort study, data on pre- and post-transplant ROTEM™ findings as obtained with EXTEM (tissue factor activation), INTEM (intrinsic system activation), FIBTEM (extrinsic system activation and inhibition of clot retraction), APTEM (extrinsic system activation and fibrinolysis inhibition), conventional laboratory coagulation tests, blood loss, transfusion of blood products, and outcome were registered. Results: Pre-transplant clot lysis indices showed a broad distribution ranging from 75% to 99% independent of the activator used (EXTEM, INTEM). During the surgical procedure, median clot lysis index values markedly increased from 92% to 97% (EXTEM) and 93% to 98% (INTEM), respectively (p < 0.0001 each). Aprotinin had no effect on either pre- or postsurgical clot lysis indices. Inhibition of platelet clot retraction with cytochalasin D (FIBTEM) markedly increased the preoperative clot lysis index. High pre- and post-transplantation clot lysis indices were associated with increased mortality irrespective of the activator used (EXTEM, INTEM) and the inhibition of fibrinolysis (APTEM). Inhibition of clot retraction (FIBTEM) abolished the association of clot lysis index with mortality in both pre- and post-transplantation samples. Conclusion: Both pre- and postoperative ROTEM™ clot lysis indices predict mortality in patients following liver transplantation. Inhibitor experiments reveal that the clot lysis index is not an indicator of fibrinolysis, but indicates platelet clot retraction. The marked increase of clot lysis index during liver transplantation is caused by a decrease in clot retraction with eventual consequences for clot stability, retraction of wound margins, and reperfusion of vessels in case of thrombosis.

Diagnosis of primary hyperfibrinolysis and in vitro investigation of the inhibitory effects of tranexamic acid in a group of dogs with sarcomas – A pilot study

Primary hyperfibrinolysis is not well characterised in canine cancer. This prospective case-control pilot study aimed to evaluate tissue plasminogen activator-modified thromboelastography (tPA-TEG) for diagnosis of primary hyperfibrinolysis in dogs with cancer and establish the in vitro therapeutic concentration of tranexamic acid (TXA).Nine dogs with sarcomas and normocoagulable thromboelastograms and 11 healthy dogs were included. For each a whole blood tPA-TEG, and four tPA-TEGs with added TXA in different concentrations were analysed. Lysis percentage at 30/60 min following maximal amplitude (LY30/60), clot lysis index (CL30/60), maximum rate of lysis (MRL), and total lysis (L) were investigated as diagnostic parameters of primary hyperfibrinolysis. In vitro TXA concentrations needed to inhibit 50% (IC50) and 90% (IC90) of the fibrinolytic potential were compared between groups.Significant primary hyperfibrinolysis (LY30 (P = 0.0001), LY60 (P = 0.003), CL30 (P = 0.01), and L (P = 0.02)) was observed in dogs with sarcomas. IC50 and IC90 of in vitro TXA for normalizing LY30 were 13.34 (SE 1.52) and 31.10 (SE 3.01) mg/L for dogs with sarcomas and 4.41 (SE 5.84) and 20.00 (SE 6.18) mg/L for healthy dogs. IC50 and IC90 for normalizing LY60 were 22.18 (SE 1.27) and 58.94 (SE 5.47) mg/L for dogs with sarcomas and 11.25 (SE 2.82) and 56.20 (SE 11.61) mg/L for healthy dogs. The IC50 for LY60 was significantly increased for dogs with sarcomas (P = 0.0003). Primary hyperfibrinolysis was documented by tPA-TEG in dogs with sarcomas. In vitro IC50 and IC90 for TXA were established. Clinical studies are required to establish therapeutic dosages in vivo.

Changes in the coagulation parameters in dogs with protein-losing enteropathy between before and after treatment.

Protein-losing enteropathy (PLE) is known to induce hypercoagulability and resultant thromboembolism in dogs. We hypothesized that hypercoagulability would improve if remission was obtained in dogs with PLE after treatment. This study aimed to evaluate the changes in the coagulation parameters after treatment in dogs diagnosed with PLE. As coagulation parameters, prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, thrombin-antithrombin complex (TAT), D-dimer, and antithrombin (AT) were measured. In addition to these parameters, rotational thromboelastometry (ROTEM), which evaluates the comprehensive coagulation and fibrinolysis reactions of whole blood, was conducted and the data of clotting time (CT), clot formation time (CFT), α angle (α), maximum clot firmness (MCF) and lysis index at 60 min (LI60) were obtained. Eleven of the 14 dogs diagnosed with PLE were classified as responders to the treatment based on the changes in their plasma albumin (ALB) concentration after treatment. Significant increase in CFT and decrease of α and MCF indicating the resolution of hypercoagulability were found after treatment in responder dogs; however, there was no significant change in the coagulation and fibrinolysis parameters other than those measured by ROTEM. This study demonstrated that the hypercoagulability detected by ROTEM was significantly improved after treatment in dogs with PLE.

The haemostatic profile in critically ill COVID-19 patients receiving therapeutic anticoagulant therapy: An observational study.

Hypercoagulability and thrombosis remain a challenge in severe coronavirus disease 2019 (COVID-19) infections. Our aim is to investigate the hemostatic profile of critically ill COVID-19 patients on therapeutic anticoagulant treatment.Forty one patients were enrolled into the study. We recruited 11 consecutive, COVID-19, patients who received therapeutic anticoagulant treatment on intensive care unit (ICU) admission. Disease severity indexes, biochemical, hematological and haemostatic parameters, endogenous thrombin potential (ETP), plasminogen activator inhibitor-1 (PAI-1) activity and extrinsically activated rotational thromboelastometry assay (EXTEM) were recorded on days 1, 3, 7. We also enrolled 9 ICU non-COVID-19, 21 non-ICU COVID-19 patients and 20 healthy blood donors as control populations.Critically ill COVID-19 patients demonstrated a more hypercoagulable and hypofibrinolytic profile related to those with COVID-19 mild illness, based on EXTEM amplitude at 10 min (A10), maximum clot firmness (MCF) and lysis index at 60 min (LI60) variables (p = 0.020, 0.046 and 0.001, respectively). Similarly, a more hypercoagulable state was detected in COVID-19 ICU patients related to non-COVID-19 ICU patients based on A10 and MCF parameters (p = 0.03 and 0.04, respectively). On the contrary, ETP and EXTEM (clotting time) CT values were similar between patients with severe and mild form of the COVID-19 infection, probably due to anticoagulant treatment given.Critically ill COVID-19 patients showed a hypercoagulable profile despite the therapeutic anticoagulant doses given. Due to the small sample size and the study design, the prognostic role of the hypercoagulability in this clinical setting remains unknown and further research is required in order to be assessed.

Pre-Liver Transplant ROTEM™ Clot Lysis Index Is Associated with 30-Day Mortality, But Is Not a Measure for Fibrinolysis.

Complex alterations of the coagulation system in end stage liver disease lead to an increased risk of bleeding and mortality. In the present study, we investigated; 1. the association of pre-liver transplant rotational thrombelastometry (ROTEM™) variables with bleeding as well as 30-day-mortality and 2. the underlying pathophysiology. After approval from the local ethics committee, rotational thrombelastometry variables, conventional laboratory coagulation values, MELD score (model of end-stage liver disease), red blood cell loss, blood product use, coagulation factors, underlying disease, and demographic data were retrospectively analysed. Pre-transplant thrombelastometry clot lysis index (CLI) and MELD were the only variables associated with mortality, bleeding and blood product use, respectively. Mortality was 4.2%, when CLI was <85%, and increased to 25.7% when the CLI was >95%. Multivariate analysis including CLI and MELD score identified the CLI as an independent and the best predictor of 30-day-mortality. Interestingly, the inhibition of fibrinolysis did neither affect CLI nor the association of the variable with mortality. Thus, fibrinolysis can be excluded as the reason for low CLI values. In conclusion, low CLI values measured before the beginning of liver transplantation are associated with reduced bleeding and mortality, but do not indicate fibrinolysis.

Effects of direct oral anticoagulants on thromboelastographic parameters and fibrin clot properties in patients with venous thromboembolism.

Data concerning the impact of direct oral anticoagulants (DOACs) on the thromboelastography (TEG) indices in venousthromboembolism (VTE) patients are limited. The goal of this study was to compare the impact of DOACs on clot properties measured in whole blood using TEG kaolin test and in plasma obtained from real-life VTE patients. We assessed 53 patients, including 20 on rivaroxaban, 20 on apixaban, and 13 on dabigatran. Using the TEG® 5000, coagulation status was evaluated in whole blood samples, while plasma fibrin clot permeability (Ks) and its susceptibility to lysis (CLT) were assessed in citrated plasma. Plasma concentrations of rivaroxaban (99 [48 - 311] ng/ml) and apixaban (85 [40 - 105] ng/ml) were positively associated with Ks and inversely with CLT, while dabigatran concentrations (71 [39 - 98] ng/ml) correlated positively with Ks. Moreover, Ks was associated with clot formation times (R and K), time to maximum clot strength (TMA), coagulation index (CI) reflecting the overall coagulation status, and whole blood clot lysis time (TEG-CLT). Blood clot lysis index (CL30) was associated with plasma CLT in all patients on DOACs, while TMA correlated with CLT only in patients on apixaban. Higher DOAC concentrations were associated with longer retardation of whole blood clot formation and longer time needed to reach maximum level of its strength as well as with more permeable clots. We concluded that plasma fibrin clot properties correlate with corresponding TEG indices suggesting that TEG might be helpful in providing prognostic information about DOAC influence in VTE patients.

Reaction of hemostasis system in hypercapnic hypoxia after the course of mexidol assessed by the method of thromboelastography

Aim. To study the reaction of hemostasis system to a single effect of hypercapnic hypoxia of maximum intensity in rats and possibility of correcting hemostasis disorders by means of a preliminary course of an antihypoxant - mexidol. Methods. The study involved sexually mature male rats (48 specimens) of the Wistar line with an average mass of 274.0 ± 32.0 g. The rats were kept on a standard diet, food and water were fed once a day between 10 and 11 hours. In the evening, animals underwent a single hypercapnic hypoxia in a special flow chamber. The state of hypercapnic hypoxia of maximum intensity was modeled at O2 content of 5.0 %, CO2 - 5.0 % during a single 20-minute exposure. As a training regimen, a 30-fold course of mexidol was used, the drug was administered intraperitoneally to rats at a dose of 50 mg/kg for 1.5 hours prior to exposure to hypercapnic hypoxia. Results. After a single exposure to hypercapnic hypoxia of maximum intensity, shortening of the onset of clot formation, an increase of alpha angle, and maximum clot density were recorded. Also, the clot formation time shortened and the maximum clot lysis index increased. With a single exposure to hypercapnic hypoxia of maximum intensity after the course of mexidol, a decrease in the maximum clot density was recorded. Conclusion. A single exposure to hypercapnic hypoxia of maximum intensity was characterized by a shift of hemostatic potential toward hypercoagulability along with fibrinolytic system activation. The course use of antihypoxant mexidol, preceding hypercapnic hypoxia of maximum intensity, significantly reduces the risk of clot formation.

Rotational thromboelastometry thresholds for patients at risk for massive transfusion

BackgroundGoal-directed hemostatic resuscitation based on thrombelastography has a survival benefit compared to conventional coagulation assays. While thrombelastography transfusion thresholds for patients at risk for massive transfusion (MT) have been defined, similar cutoffs do not exist for the other commonly used viscoelastic assay, rotational thromboelastometry (ROTEM). The purpose of this study was to develop ROTEM blood product thresholds in patients at risk for MT. MethodsROTEM was assessed in trauma activation patients admitted from 2010 to 2016 (n = 222). Receiver operating characteristic curve analyses were performed to test the predictive performance of ROTEM measurements in patients requiring MT. The Youden Index defined optimal thresholds for ROTEM-based resuscitation. ResultsPatients who required MT (n = 37, 17%) were more severely injured. EXTEM clotting time (CT) was longer in patients with MT compared to non-MT (87 versus 64 s, P < 0.0001). EXTEM angle was shallower in MT patients compared to non-MT (54° versus 69°, P < 0.0001). Clot amplitude after 10 min (CA10) was less in MT compared to non-MT patients (30.5 versus 50 mm, P < 0.0001). Clot lysis index 60 min (CLI60) was lower in patients who had MT than non-MT (47 versus 94%, P = 0.0006). EXTEM CT yielded an area under the receiver operating characteristic curve (AUROC) = 0.7116 and a cut point of >78.5 s. EXTEM angle had an AUROC = 0.865 and a cut point of <64.5°. EXTEM CA10 had an AUROC = 0.858, with a cut point of <40.5 mm. CLI60 had an AUROC = 0.6788 with a cut point at <74%. ConclusionsWe have identified ROTEM thresholds for transfusion of blood components in severely injured patients requiring an MT. Based on our analysis, we propose plasma transfusion for EXTEM CT > 78.5 s, fibrinogen for angle <64.5°, platelet transfusion for CA10 < 40.5 mm, and antifibrinolytics for CLI60 < 74%.

Incidence and clinical significance of hyperfibrinolysis during living donor liver transplantation.

: We evaluated the incidence and clinical significance of hyperfibrinolysis during living donor liver transplantation (LDLT) using viscoelastic coagulation tests. We retrospectively reviewed adult LDLT recipients from February 2010 to February 2015. Hyperfibrinolysis was defined when clot lysis index [LY60 = (MA - A60)/MA × 100, %] was less than 85, where A60 is the clot amplitude at 60 min after maximum amplitude (MA) occurred. Viscoelastic coagulation tests were performed six times (T1: immediately after anesthetic induction, T2: end of preanhepatic phase, T3: 1 h after anhepatic phase, T4: 5 min after reperfusion, T5: 1 h after reperfusion, and T6: 3 h after reperfusion). One hundred-ten recipients were included in final analysis. Hyperfibrinolysis was uncommon in preanhepatic phase (0% at T1 and 4.5% at T2) and aggravated during anhepatic phase and peaked immediately after reperfusion, 18% at T3 and 71% at T4. However, hyperfibrinolysis nearly disappeared 1 h after reperfusion and did not recur; 0.9% at T5 and 0% at T6. Hyperfibrinolysis was not predicted from preoperative demographics and coagulation profiles. However, the degree of coagulation profile derangements and intraoperative blood loss was greater in the hyperfibrinolysis group. During LDLT, hyperfibrionlysis frequently occurred at anhepatic phase and immediately after reperfusion, but it was resolved during postreperfusion phase.

In Vitro Evaluation of the Effect of Haemodilution with Dextran 40 on Coagulation Profile as Measured by Thromboelastometry and Multiple Electrode Aggregometry

We evaluated the effects of haemodilution with either dextran 40 or 0.9% normal saline on coagulation in vitro using rotational thromboelastometry (ROTEM®, Pentapharm Co., Munich, Germany) and multiple electrode aggregometry (Multiplate® Platelet Function Analyser, Dynabyte, Munich, Germany). Venous blood samples obtained from 20 healthy volunteers were diluted in vitro with dextran 40 or normal saline by 5%, 10% and 15%. Fibrinogen concentration, ROTEM-EXTEM® (screening test for the extrinsic coagulation pathway), FIBTEM® (an EXTEM-based assay of the fibrin component of clot) parameters including coagulation time, clot formation time, alpha angle, maximum clot firmness and lysis index were measured in the undiluted sample and at each level of haemodilution. Dextran 40 at 15% haemodilution significantly prolonged coagulation time, clot formation time and significantly decreased the alpha angle and maximal clot firmness (EXTEM amplitude at five minutes [A5] and ten minutes [A10]) compared with normal saline. The FIBTEM assay (maximal clot firmness and FIBTEM A5 and A10) showed a marked decrease in maximal clot firmness at all dilutions suggesting impaired fibrinogen activity and a risk of bleeding. Multiple electrode aggregometry did not demonstrate any platelet dysfunction. Haemodilution with dextran 40 causes significant impairment in clot formation and strength compared to saline haemodilution and undiluted blood. At the levels of in vitro haemodilution designed to reflect the clinical use of dextran infusions, no significant fibrinolysis or platelet inhibition was observed.

Influence of cryoprecipitate, Factor XIII, and fibrinogen concentrate on hyperfibrinolysis.

Hyperfibrinolysis is a potentially life-threatening condition associated with poor clot integrity and excessive bleeding. Although antifibrinolytics are an effective treatment, more liberal use of these drugs may lead to a prothrombotic risk, and an earlier and potentially safer treatment option would be desirable. Hyperfibrinolysis has been shown to be attenuated by in vitro supplementation of purified human Factor (F)XIII concentrate. Cryoprecipitate represents an alternative source of FXIII and the only approved source of concentrated FXIII in some countries. The aim of this study was to investigate whether cryoprecipitate, FXIII, and fibrinogen concentrate mitigate hyperfibrinolysis. Ten citrate blood specimens from healthy subjects were spiked with tissue plasminogen activator (t-PA) and subsequently supplemented with cryoprecipitate, FXIII, fibrinogen concentrate, and ɛ-aminocaproic acid (EACA). Thromboelastometry tests were performed at baseline, after t-PA, and after supplementation. Hyperfibrinolysis was assessed using the clot lysis index at 60 minutes (LI60; reciprocal of maximum lysis). The LI60 was significantly improved (fibrinolysis attenuated) after cryoprecipitate supplementation compared to t-PA alone and compared to FXIII and fibrinogen concentrate. Hyperfibrinolysis was only fully reversed using EACA. In addition, cryoprecipitate demonstrated the least variability in the attenuation of hyperfibrinolysis among 10 healthy subjects, compared to FXIII and fibrinogen concentrate. This is the first study to show that cryoprecipitate is able to significantly mitigate hyperfibrinolysis in an in vitro model. Further investigations are warranted to determine whether cryoprecipitate may have a previously unrecognized benefit and should be administered earlier in resuscitation protocols.

Reference Intervals of Thromboelastometric Evaluation of Coagulation in Pediatric Patients with Congenital Heart Diseases: A Retrospective Investigation.

BackgroundRotational thromboelastometry (ROTEM®) is a point-of-care test for coagulation, enabling physicians to make a swift decision. The aim of this investigation was to establish reference intervals of thromboelastometric evaluation for coagulation in pediatric patients with congenital heart diseases (CHD).Material/MethodsAs baseline data, 3 assays of ROTEM® (INTEM, EXTEM, and FIBTEM) were measured after anesthesia induction. ROTEM® parameters were clotting time (CT), amplitude at 10 min (A10), clot formation time (CFT), α angle, maximal clot firmness (MCF), clot lysis index at 60 min (LI60), and maximal clot elasticity (MCE). As age is a well-known factor for maturation, age groups were determined as follows; 1) <1 month, 2) 1–3 months, 3) 4–12 months, 4) 1–3 years, 5) 4–6 years, 6) 7–12 years, and 7) 13–16 years. Reference limits representing 95% of distribution of ROTEM® parameters and 90% confidence intervals of upper and lower reference limits were calculated.ResultsThe data of 413 patients were analyzed. Although INTEM CT was prolonged, significantly shorter CT and CFT, steeper α, and greater A10, MCF, and MCE were shown in patients age <3 months compared to older children.ConclusionsReference intervals of thromboelastometric evaluation for coagulation from pediatric patients with CHD were shown to have similar pattern to those obtained from healthy pediatric patients. Pediatric patients with CHD, even with cyanosis, were demonstrated to have functionally intact coagulation profile before surgery.

Autotransfusion of Hemothorax Blood Is Prothrombotic but Inhibits Platelet Aggregation: A Potentiator of Disseminated Intravascular Coagulation

IntroductionHemostatic resuscitation in combat casualty care presents unique challenges not typically encountered in metropolitan areas. Fresh whole blood and blood components are considered preferable to crystalloid or colloid solutions, but availability may be limited in austere wartime environments. Autologous shed blood from a traumatic hemothorax or hemoperitoneum, in theory, is an attractive alternative. This position is supported by the American Academy of Blood Banking, Eastern Association for the Surgery of Trauma, and Society of Critical Care Medicine, despite the fact that the safety and efficacy of shed blood has never been evaluated in randomized trials. Recent reports suggest that shed blood has poor hemostatic properties. This study was performed to evaluate the effects of shed hemothorax plasma and microparticles on platelet function and global tests of coagulation.MethodsShed traumatic hemothorax blood was obtained from 17 adult trauma patients requiring tube thoracostomy, every hour up to 4 hours after placement, according to IRB approved protocol. The hemothorax plasma was then isolated and frozen for later analysis. The effects of shed frozen plasma at 1 and 4 hours (HFP1; HFP4) was examined by performing mixing studies with fresh platelet rich plasma from normal donors at pre-specified serial dilutions of 1:8, 1:4, and 1:2 to mimic intravascular resuscitation . This was then analyzed by several assays. Thromboelastometry (ROTEM) of HFP was done to evaluate clotting time (CT), clot formation time (CFT), alpha angle, and lysis index at 45 minutes. Platelet aggregometry was done to assess the effect of shed HFP on platelet function in response to adenosine diphosphate (ADP), arachidonic acid (ASPI) and collagen. Fibrin degradation products (FDP), von Willebrand factor (vWF) and tissue factor (TF) levels in HFP were determined by enzyme-linked immunosorbent assays (ELISA ). vWF multimers in HFP were further separated by size using gel electrophoresis and detected by immunostaining. Microparticle analysis was performed using isolated microparticles from ultra-centrifuged HFP1 and HFP4 (HMP1 and HMP4) and compared to control isolated microparticles from fresh frozen plasma (FMP). HMP and FMP were then diluted with platelet rich plasma to a predetermined platelet count after which, ROTEM and platelet aggregometry were performed as described above. Non-diluted HFP and resuspended HMP1, HMP4 and FMP were then analyzed by flow cytometry for a variety of microparticle (MP) derived antigens including APC-H7-CD41a (GPIIb/IIIa derived MP), and APC-CD235a (Glycophorin A from red cell derived MP), and FITC-Lactadherin phosphatidylserine (platelet derived MP).ResultsROTEM of HFP demonstrated a CT of 55.8% and 60.6% at the 1:8 dilution and 69.3% and 71.4% at the 1:2 dilution, for HFP1 and HFP4 respectively, compared to platelet rich plasma (PRP) and FFP (p<0.05) controls. Similar findings were seen in the CFT at the 1:8 dilution. HMP1 and HMP4 demonstrated decreased CT when compared to PRP and FMP (p<0.05).HMP1 and HMP4 inhibited platelet aggregation in response to ADP, TXA2, and collagen with data expressed as area under the curve (U), when compared to FMP and PRP, all statistically significant (p<0.05). For example, PRP and FMP response to ADP was greater than 100U and HMP less than 50U (p<0.05). ELISA of HFP demonstrated significantly higher levels of FDP (>700ng/mL vs 0ng/mL p<0.05) and TF (>500 pg/mL vs <200 pg/mL p<0.05) when compared to FFP controls.Flow cytometry showed increased microparticle concentrations in HFP1, HFP4, HMP1, and HMP4 samples with greater than 10 fold increase (MP/uL) in several markers (p<0.05) when compared to FFP and FMP. vWF multimer ratio demonstrated a loss in high molecular weight multimers and a gain in low molecular weight multimers in HFP1 and HFP4 (ratio high molecular weight:low molecular weight <1) when compared to FFP (ratio 2.5) with p value <0.05.ConclusionThese results demonstrate that autologous shed hemothorax blood promotes a prothrombotic state due to increased tissue factor and microparticle content. Furthermore, clot localization may be impaired through inhibition of platelet aggregation by microparticles and degradation of vWF. These data suggest that randomized trials are indicated to establish the safety and efficacy of autologous shed traumatic hemothorax blood for trauma resuscitation. DisclosuresNo relevant conflicts of interest to declare.

Recombinant tissue-type plasminogen activator–evoked hyperfibrinolysis is enhanced by acidosis and inhibited by hypothermia but still can be blocked by tranexamic acid

Hypothermia and acidosis have been suggested as key initiators of trauma-induced coagulopathy, and severe bleeding caused by hyperfibrinolysis (HF) predicts mortality. We tested in vitro (1) whether clinically relevant grades of hypothermia, acidosis, and their combination impact on recombinant tissue-type plasminogen activator (r-tPA)-evoked HF and assessed (2) the efficacy of tranexamic acid (TA) in inhibiting fibrinolysis under such conditions. To assess the effects of r-tPA-evoked HF, venous blood (3,000 μL) from healthy volunteers was incubated with r-tPA (final concentration, 100 ng/mL) or saline (control) for 30 minutes at the final measurement temperature. Before thromboelastometric measurements, samples were acidified (addition of 40 μL of 0.5 or 1N hydrochloric acid, respectively) to achieve a pH (alpha-stat) of approximately 7.1 or 6.9, respectively. To assess effects of hypothermia, tests were performed at blood/thromboelastometer temperatures of 33°C and 37°C, respectively. Coagulation was analyzed using rotational thromboelastometry (ROTEM), particularly assessing the Clot Lysis Index (CLI) after 45 minutes (CLI45) in extrinsically activated assays (EXTEM). Addition of r-tPA evoked fibrinolysis (CLI45: median, 64; 25th/75th percentile, 48/80) compared with saline controls (CLI45: median, 93; 25th/75th percentile, 91/96). Moderate acidosis (pH [mean ± SD], 7.12 ± 0.03) did not affect r-tPA-induced fibrinolysis. However, severe acidosis (pH, 6.91 ± 0.02) significantly aggravated r-tPA-induced fibrinolysis (CLI45: median, 49; 25th/75th percentile, 26/71; p = 0.0039) compared with fibrinolysis with normal pH and normothermia (median, 77; 25th/75th percentile, 65.5/83). In contrast, hypothermia (33°C) at normal pH (median ± SD, 7.37 ± 0.02) markedly mitigated fibrinolysis (CLI45: median, 94; 25th/75th percentile, 88/96; p = 0.0156) compared with normothermia (CLI45: median, 64; 25th/75th percentile, 48/80). TA (final concentration, 0.33 mg/mL) abolished r-tPA-evoked fibrinolysis even during severe acidosis (CLI45: median, 92; 25th/75th percentile, 86.5/94; p = 0.0039). Severe acidosis significantly increases r-tPA-evoked fibrinolysis, whereas hypothermia markedly mitigates HF. The latter finding may imply that rapid rewarming of trauma patients might aggravate fibrinolysis. TA reliably abolished fibrinolysis also under these conditions, supporting its role in trauma-induced coagulopathy.

OC-069 Rotational thromboelastometry in cirrhosis: hypercoagulable and hyperfibrinolytic

IntroductionCirrhotics have complex acquired derangements of haemostasis. Routine coagulation tests suggest a hypocoagulable profile, resulting in frequent administration of blood components for prophylaxis and treatment of bleeding. Rotational thromboelastography (ROTEM®),...

Sa1035 Rotational Thromboelastometry in Cirrhosis: Hypercoagulable and Hyperfibrinolytic

Introduction Cirrhotics have complex acquired derangements of haemostasis. Routine coagulation tests suggest a hypocoagulable profile, resulting in frequent administration of blood components for prophylaxis and treatment of bleeding. Rotational thromboelastography (ROTEM ® ), unlike standard coagulation tests, provides a real-time measurement of clot formation, strength and stability in whole blood and may more accurately reflect in vivo coagulation. We aimed to (1) identify the key derangements in the haemostatic pathways in patients with cirrhosis; (2) determine the prevalence of overt hyperfibrinolysis and whether this could be improved with anti-fibrinolytics. Methods We used ROTEM ® to investigate: (1) Clotting time (CT) and maximum clot firmness (MCF) in stable, non-bleeding cirrhotics compared to healthy volunteers; (2) The presence of overt hyperfibrinolysis and whether this could be reversed by spiking blood samples ex vivo with the antifibrinolytic aprotinin (APTEM test). Overt hyperfibrinolysis was defined by a maximum lysis (ML) of >15% and by comparing the clot lysis index at 60 min between EXTEM and APTEM parameters. Results 106 adult cirrhotics and 28 healthy volunteers were enrolled after informed consent. Median EXTEM CT was shorter in cirrhotics than controls (51s vs 58s, p Conclusion Cirrhotics have a hypercoagulable clotting time, despite prolonged PT, APTT and thrombocytopenia supporting the concept of re-balanced haemostasis. Use of ROTEM ® may avoid unnecessary and potentially harmful transfusion of pro-coagulant blood components in cirrhotics. The high prevalence of overt hyperfibrinolysis in cirrhosis requires further elucidation and clinical studies to investigate the potential role of anti-fibrinolytics in the prophylaxis of variceal bleeding. Competing interests None declared.