Why is everyone so excited about thromboelastrography (TEG)?

Thromboelastogram and coagulation function index: relevance for female breast cancer

Introduction

Screening and postoperative intervention of breast tumors are critical for the effective diagnosis and treatment of disease development, and reliable diagnostic/screening methods become a key link.

Objective

Thromboelastogram (TEG), routine platelet (PLT) count, and the coagulation function indicators in patients with different breast diseases were determined and analyzed to explore their predictive value in secondary bleeding disorders.

Methods

A total of 131 patients with breast diseases, admitted to Jiangsu University Affiliated Hospital from January 2019 to December 2022, were selected as the research subjects. The detection items were analyzed using the receiver operating curve (ROC) after grouping for secondary bleeding disorders of patients with breast cancer.

Results

The reaction (R) and the coagulation (K) times were lower in the malignant breast disease group, while the coagulation angle (α), maximum amplitude (MA), coagulation index (CI), fibrinogen (FIB), and D-dimer (D-D) were higher than those in the benign breast disease group. The t-tests proved that the MA and FIB values were statistically significant (p < 0.05) in the benign and malignant breast disease groups. The R and K in patients with breast diseases were positively correlated with the activated partial thromboplastin time (aPTT) and D-D, but were negatively correlated with PLT. The α angle was negatively correlated with aPTT and D-D, but was positively correlated with PLT. The MA for PLT function was positively correlated with FIB and PLT. CI was negatively correlated with aPTT, thrombin time (TT), and D-D, but was positively correlated with PLT. ROC curve analysis showed that the CI and α angle had a significant predictive value, whereas the correlation of the other indicators was relatively low.

Conclusion

Coagulation tests showed significant differences in patients with breast cancer, differing from those with benign breast diseases. TEG combined with conventional coagulation indicators is potentially valuable for the prediction of secondary bleeding disorders in patients with breast cancer.

Diagnostic value of mean platelet volume combined with thromboelastography for coagulation state after total knee arthroplasty

BACKGROUND

The main objective of this study was to predict the status of blood and the occurrence of lower limb deep vein thrombosis (DVT) after total knee arthroplasty(TKA) by means of mean platelet volume (MPV) combined with thromboelastography (TEG).

METHODS

We collected 180 patients who underwent unilateral total knee arthroplasty between May 2015 and March 2022, and the patients were divided into DVT group and control group according to whole-leg ultrasonography on the seventh postoperative day. Blood count and TEG were performed on the day before surgery, the first day after surgery and the seventh day respectively. Multifactorial analysis was used to investigate whether the relevant parameters were independent predictors of DVT after TKA.

RESULTS

MPV has the strongest correlation with the maximum amplitude (MA), followed by alpha-angle; MPV and alpha-angle on the first postoperative day are independent predictors of DVT. MPV in patients with thrombosis tends to rise and then fall in the perioperative period. The optimal threshold for MPV to predict thrombosis is 10.85 fL and the area under the ROC curve is 0.694, The area under the ROC curve increases to 0.815 using MPV combined with alpha-angle. In addition, MA, α-angle, composite coagulation index (CI) and MPV were all statistically higher in the DVT group than in the control group (p < 0.001).

CONCLUSION

MPV is a predictor of DVT after TKA. It can reflect the hypercoagulable state of blood after surgery; Combination of MPV and alpha-angle on the first day after surgery in patients with TKA improves predictive power of DVT.

Clinical Application of Thromboelastography in Acute Ischemic Stroke

Acute ischemic stroke (AIS), characterized by high morbidity and mortality, has imposed a considerable burden on society. Despite rapid development in the treatment of AIS, there is still a high risk of recurrence. Furthermore, there is a time delay in waiting for the results of conventional coagulation tests in candidate patients for intravenous thrombolysis therapy. Heterogeneous responses to antiplatelet, intravascular thrombolysis, and endovascular therapies also worsen the situation. Thromboelastography (TEG), as a global and portable detection method for hemostasis, facilitates clinicians in disease monitoring, treatment evaluation, and prognosis prediction in AIS. In this narrative review, we provided a comprehensive summary of the clinical application of TEG in ischemic stroke and gave insights to further studies.

Identification of Early Derangements of Coagulation, Hematological and Biochemical Profiles in Patients with Acute Pancreatitis

BACKGROUND

Acute pancreatitis (AP) is a severe disease involving various pathological processes. We aimed to use rapid -thromboelastography (r-TEG) combined with conventional coagulation assays (CCAs) and other laboratory tests, to identify early derangements in coagulation, hematological, and biochemical profiles in patients with AP.

METHODS

We enrolled 177 patients diagnosed with AP and 121 controls. Blood samples were analyzed using r-TEG, CCAs, and hematological and biochemical tests within 2 h of patient admission. All testing parameters were compared between the patients and the controls. Pearson's correlation coefficient was used to determine the correlation between the parameters among the patients. Logistic regression analysis was performed to evaluate the effects of the variables (demographic, coagulation, hematological and biochemical) on AP.

RESULTS

Using r-TEG and CCAs, we observed differences in coagulation parameters between the patients with AP and the controls. The r-TEG results showed a pro-coagulant state and increased platelet activation in AP patients. Pearson's correlation analysis showed that inflammatory indicators were strongly correlated with coagulation/platelets in the pathological process of AP. Logistic regression analysis revealed that age, K, neutrophil (NEUT), triglyceride (TG) and blood amylase (AMY) were significantly associated with the development of AP.

CONCLUSION

Coagulation profile and platelet play essential roles in the pathogenesis of AP. Pro-coagulant state and increased platelet activation in patients with AP were demonstrated using r-TEG. The r-TEG parameter K, age, NEUT, TG, and AMY may be used as potential indicators of AP.

Use of thromboelastography before the administration of hemostatic agents to safely taper recombinant activated factor VII in acquired hemophilia A: a report of three cases

Background

Acquired hemophilia A (AHA) is a rare autoimmune disease characterized by bleeding events. Recombinant activated factor VII (rFVIIa) is a first-line bypassing agent, which is effective against clinically significant bleeding. However, there is no standard way of tapering and discontinuing rFVIIa, mainly because there is no established method for monitoring rFVIIa therapy for AHA.

Case presentation

Here, we report three AHA cases, in which we adjusted the rFVIIa dosing interval based on the results of thromboelastography (TEG) performed just before the administration of the next dose of rFVIIa. The dosing interval of rFVIIa was prolonged based on the reaction rate time (R) according to TEG, which is correlated with coagulation factor activity. The R-value reference range reported by the manufacturer of the TEG system was used as a threshold for making decisions. In these three cases, there was no rebleeding, and the patients’ ability to perform activities of daily living did not decline.

Conclusion

Our cases suggest that conducting TEG-based monitoring just before the administration of the next dose of rFVIIa may be useful for guiding increases in the rFVIIa dosing interval without causing rebleeding events. Further investigations are warranted to examine how TEG could be used to determine the most appropriate rFVIIa dosing interval, e.g., through regular TEG-based monitoring, and the optimal TEG-derived threshold for indicating changes to the rFVIIa dosing interval.

Comparison of the effects of open-tube and evacuated tube-assisted sampling methods on thromboelastography variables for blood samples from healthy dogs

OBJECTIVE

To compare the effects of open-tube blood sampling with previously investigated blood sampling methods via evacuated tube on thromboelastography variables for blood samples from dogs.

ANIMALS

10 healthy Beagles from the research colony owned by the Clinic of Small Animal Internal Medicine, University Veterinary of Medicine, Vienna, were used.

PROCEDURES

In this prospective study, blood was sampled from each dog serially into citrate solution-containing tubes via 20-gauge needle. One evacuated tube was filled from a jugular vein via the evacuated tube port, and the second tube was opened and filled by catching blood flowing through the needle from a lateral saphenous vein. Venipuncture quality was scored with a previously described method. Thromboelastography was performed for each sample.

RESULTS

Inferential statistics used with the Wilcoxon signed rank test showed significant differences in reaction time (R) of 3.43 ± 0.84 minutes versus 4.53 ± 0.62 minutes (mean ± SD) between evacuated tube assisted and open-tube sampling, respectively. No other significant differences were identified.

CLINICAL RELEVANCE

The sampling methods compared have a small but significant effect on R in thromboelastographic analysis for blood samples from healthy dogs. Shear stress by vacuum sampling seems to accelerate coagulation in jugular blood samples harvested by evacuated tube, resulting in a shortened R. Results suggested that the open-tube method avoids shear stress induced activation of coagulation and is an appropriate sampling method for thromboelastography when used within a standardized protocol.

Gender Differences do not Influence the Blood Coagulopathy in Patients Undergoing Total Knee Arthroplasty: A Retrospective Thromboelastography Analysis

Objective

Deep vein thrombosis (DVT) is one of the severe complications after total knee arthroplasty (TKA). Gender has been considered to influence the incidence of the thrombosis formation in TKA patients. However, it remains controversial which gender would be more prone to form thrombosis. The aim of this study was to assess the effects of gender differences on coagulation status after TKA via the thromboelastography (TEG).

Methods

A total of 57 male patients who underwent primary TKA from September 2015 to January 2021 were included in this study. According to the matching principle of age, body mass index (BMI), and anticoagulation treatment, 60 female patients were selected. The conventional coagulation tests, routine blood tests, and thromboelastography were conducted before the operation, 1 day and 7 days after the operation. In addition, Doppler ultrasound was also performed 1 day before the operation and at the 7 days after the operation. The parameters of conventional coagulation tests, routine blood tests, and thromboelastography were compared between the two groups.

Results

There were no significant differences in the blood transfusion rate, the incidence of DVT during the perioperative period, D-dimer (D-D), fibrin degradation products (FDP), hemoglobin (HB), hematocrit (HCT), prothrombin time (PT), activated partial thromboplastin time (APTT), and C-reactive protein (CRP) at any corresponding time point between the male group and the female group (P > .05). There were no significant differences in neutrophil-to-lymphocyte ratio (NLR) preoperatively; however, there were significant differences in NLR 1 day after the surgery and 7 days after the surgery between the two groups (P < .05). There were significant differences in reaction time (R) and α angle 1 day after the surgery between the two groups (P < .05), but there were no significant differences in other TEG indexes at any corresponding time point between the two groups (P > .05). Binary logistic regression analysis demonstrated that gender, age, BMI, tourniquet application time were not independent predictors (P > .05).

Conclusion

Gender differences have no significant influence in TKA patients with regard to conventional coagulation tests and thromboelastography.

Changes in Coagulation and Fibrinolysis in Post-Cesarean Section Parturients Treated With Low Molecular Weight Heparin

BACKGROUND

Cesarean section is an independent risk factor for Venous thromboembolism (VTE). Low molecular weight heparin (LMWH) is extensively used for VTE prophylaxis after cesarean section. In this study, the effects of LMWH on coagulation and fibrinolysis after cesarean section and its clinical value were explored by studying the changes in laboratory indicators.

METHODS

Antepartum and postpartum peripheral blood of 44 pregnant women who underwent vaginal delivery and 44 pregnant women who underwent cesarean section treated per routine with LMWH thromboprophylaxis on the first day post-operatively were collected for the following tests: D-dimer; thrombotic markers such as thrombomodulin (TM), thrombin-antithrombin complex (TAT), α2-plasmin inhibitor-plasmin complex (PIC), and tissue plasminogen activator inhibitor complex (t-PAIC); thromboelastography.

RESULTS

Compared to the antepartum levels, PIC increased, TM, TAT, and t-PAIC decreased significantly in the parturients after a spontaneous vaginal delivery. Compared to the antepartum levels, parturients routinely treated with LMWH after cesarean section had higher PIC levels and lower D-dimer, TAT, and t-PAIC levels. Compared with parturients after vaginal delivery, parturients treated with LMWH after cesarean section had higher levels of TM, R, and MA, while there was no significant differences in the levels of D-dimer, TAT, PIC, t-PAIC, K, angle, LY30, and CI.

CONCLUSION

The coagulation and fibrinolytic systems in gravidas and parturients are in a high level of dynamic equilibrium. The levels of coagulation and fibrinolytic system activation were similar in parturients who were routinely treated with LMWH after cesarean section compared with parturients after a spontaneous vaginal delivery.

Tourniquet use in primary total knee arthroplasty is associated with a hypercoagulable status: a prospective thromboelastography trial

STUDY DESIGN

Prospective study.

PURPOSE

The main purpose of this study was to investigate whether the use of a tourniquet changes the blood coagulation state following primary total knee arthroplasty (TKA) by means of conventional coagulation tests and thromboelastography (TEG) analyses.

METHODS

A total of 154 patients who underwent primary unilateral TKA from January 2018 to October 2020 were enrolled. Seventy-nine patients were randomized into a tourniquet group, and 75 were randomized into a no-tourniquet group. Demographic data, surgical time, intra-operative blood loss, transfusion rate, and wound complications were collected. Complete blood count, conventional coagulation tests, and TEG were performed the day before surgery, one day after surgery, three days after surgery, and seven days after surgery. Lower extremity Doppler ultrasound was performed the day before surgery and seven days after surgery.

RESULTS

The baseline characteristics of the patients were similar between the two groups. Hidden blood loss, transfusion rate, and wound complications were similar between the two groups, but the intra-operative blood loss of the tourniquet group was lower than that of the no-tourniquet group. The calculated total blood loss of the tourniquet group was higher than that of the no-tourniquet group. In terms of conventional coagulation tests and TEG, the tourniquet group had higher values of fibrin degradation products, D-dimer, maximum amplitude, and coagulation index (p < 0.001). The incidence of deep vein thrombosis (DVT) in the tourniquet group was higher than that in the no-tourniquet group (21.5% compared with 8%; p = 0.019).

CONCLUSION

The application of a tourniquet during TKA significantly increases the amount of calculated total blood loss and does not decrease the post-operative transfusion rate. Using a tourniquet in routine TKA exacerbates the early post-operative hypercoagulable status together with a higher incidence of below-knee asymptomatic DVT observed via conventional coagulation tests, TEG, and ultrasonic Doppler.

Psoriatic disease is associated with systemic inflammation, endothelial activation, and altered haemostatic function

Psoriasis is a chronic, immune-mediated inflammatory skin disease, affecting approximately 2% of the general population, which can be accompanied by psoriatic arthritis (PsA). The condition has been associated with an increased cardiovascular burden. Hypercoagulability is a potential underlying mechanism that may contribute to the increased risk of major cardiovascular events in psoriatic individuals. Whole blood samples were collected from 20 PsA patients and 20 healthy individuals. The concentrations of inflammatory molecules (C-reactive protein, serum amyloid A, soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, and soluble P-selectin) were determined by enzyme-linked immunosorbent assays. In addition, clotting efficiency was evaluated by thromboelastography. The fibrin network architecture was also assessed by scanning electron microscopy. Elevated levels of circulating inflammatory molecules were significantly associated with the presence of psoriatic disease. Furthermore, an increased tendency towards thrombus formation was significantly predictive of disease presence. Scanning electron microscopy revealed that fibrin clots were denser in psoriatic individuals, compared to healthy controls, with an increased fibrin fibre diameter associated with psoriatic disease. Our results add to the accumulating evidence of the systemic nature of psoriasis and the subsequent risk of cardiovascular comorbidities, potentially due to an acquired hypercoagulability. We suggest that haemostatic function should be monitored carefully in psoriatic patients that present with severe disease, due to the pre-eminent risk of developing thrombotic complications.

Comparison between thromboelastography and conventional coagulation assays in patients with deep vein thrombosis

BACKGROUND

Conventional coagulation assays (CCAs) are of limited value in the assessment of coagulation status in patients with deep vein thrombosis (DVT). We aimed to compare thromboelastography (TEG) and CCAs in identifying DVT and evaluating coagulation status in DVT patients.

METHODS

Sixty-six patients diagnosed with DVT and forty healthy controls were enrolled. Blood samples were collected within 4 h of patients' admission to hospital before any operation and tested by TEG and CCAs. TEG and CCA parameters were compared between DVT patients and controls. The ability of each parameter in identifying DVT was assessed. Pearson's correlation was used to determine the correlation between TEG and CCA parameters among the study population.

RESULTS

TEG showed significant differences between DVT patients and controls, indicating a hypercoagulable tendency in patients suffering from DVT. In contrast, no significant difference regarding CCAs was observed between the DVT and control group. Furthermore, TEG displayed a better capacity in identifying DVT than CCAs. In addition, Pearson's correlation analysis showed TEG and CCA parameters had few correlations.

CONCLUSION

TEG has advantages in identifying DVT and detecting hypercoagulability, and provides a better insight in evaluating coagulation status in patients with DVT than CCAs.

Correcting Coagulopathy With Fresh Frozen Plasma in the Surgical Intensive Care Unit: How Much Do We Need to Transfuse?

INTRODUCTION

Thromboelastography (TEG) is an assay that assesses the coagulation status. Patients with prolonged reaction time (R) require fresh frozen plasma (FFP); however, the volume required to correct the R time is unknown. We sought to quantify the volume required to correct the R time and calculate the response ratio in our surgical intensive care unit (SICU) to allow for targeted resuscitation.

METHODS

Surgical intensive care unit patients between Aug 2017 and July 2019 with a prolonged initial R time and at least two TEG tests performed within 24 hours were included. The response ratio was defined as the change in the R time divided by the number of FFP units. High responders (response ratio >5 minutes/unit) were compared to low responders (response ratio ≤5 minutes/unit).

RESULTS

Forty-six patients were included. While the mean response ratio was 5 minutes/unit, there was significant variation among patients. There were 28.0 (60.9%) low responders and 18.0 (39.1%) high responders. Low responders were more likely male (64.0% vs. 33.0%, P = .04), had a higher Acute Physiology and Chronic Health Evaluation (APACHE) IV score (42.0 vs. 27.0, P = .03), and a higher mortality rate (54.0% vs. 22.0%, P = .04).

CONCLUSIONS

On average, one unit of FFP corrects the R time by 5 minutes; however, there was significant variation between high and low responders. Male patients with higher APACHE IV score are expected to be low responders with a higher mortality rate. These findings can guide FFP transfusion and provide additional prognostication.

Thromboelastography utilization for dabigatran reversal in a patient with acute kidney injury

PURPOSE

This case report describes utilization of thromboelastography (TEG) in the setting of an acute major bleed in a patient on dabigatran who had concomitant acute kidney injury.

SUMMARY

An 80-year-old female presented to the emergency department after a fall with complaints of pain in her knee, shoulder, and hip. Her medical history was significant for coronary artery disease, for which she took clopidogrel 75 mg daily, and atrial fibrillation, for which she took dabigatran 150 mg twice daily. The physical exam was remarkable for pain within the shoulder, hip, and knee, which had swelling and ecchymosis that extended into the right thigh. Given the possibility of compartment syndrome with multiple possible etiologies of coagulopathy, TEG and computed tomography angiography (CTa) of the right lower extremity were performed. The initial TEG showed prolonged R time and activated clotting time, indicating clotting factor dysfunction with no additional coagulopathy noted, including antiplatelet effects. On the basis of the TEG and CTa findings, it was decided to reverse dabigatran with 5 grams of idarucizumab. Approximately 1 hour after administration of idarucizumab, the patient was taken to interventional radiology where a limited angiogram of the right lower extremity showed no active extravasation. Because of the patient's renal dysfunction and the possibility of rebound hypercoaguability, repeat TEG tests were ordered at 4 and 8 hours after the initial reversal to ensure clearance of idarucizumab-dabigatran complexes. The repeat TEG values showed complete reversal of the initial coagulopathy noted. During the admission, the patient required no blood transfusions or surgical interventions and all her initial laboratory results improved.

CONCLUSION

Serial TEG testing was successful at managing multiple coagulopathies in a patient at risk for trauma-induced compartment syndrome.

Intravenous administration of tranexamic acid in total hip arthroplasty does not change the blood coagulopathy: a prospective thrombelastography analysis

OBJECTIVE

Despite the wide use of tranexamic acid (TXA) in the perioperative period of total hip arthroplasty (THA), whether the hemostatic state changes after the application of intravenous (IV)-TXA are still unknown. The aim of this study was to investigate whether IV administration of TXA changes the blood coagulation following primary THA via thrombelastography (TEG) analysis and conventional laboratory tests.

METHODS

A total of 174 patients who underwent primary THA from September 2016 to July 2018 were selected. They were randomly divided into two groups, 86 patients with IV administration of 15 mg/kg TXA and 88 controls without TXA usage. Demographic data, TEG paremeters, d-dimer levels, fibrin degradation products, hemoglobin, hematocrit concentration, platelet, transfusion rates, perioperative blood loss, and the occurrence of deep vein thrombosis were collected. TEG and conventional laboratory tests were performed the day before operation, the first day after operation, and seventh day after operation.

RESULTS

There were no differences with regard to TEG or conventional laboratory tests between the two groups (p > 0.05). The total blood loss and drain blood loss in the TXA group were significantly lower than those in the control group (p < 0.05). The transfusion rates and the volume of blood transfusion of the control group were higher than those of the TXA group (p < 0.05).

CONCLUSION

The administration of IV-TXA resulted in a significant reduction in total blood loss, transfusion volumes, and transfusion rates without the increase of thromboembolic complications. Moreover, it was confirmed that TXA would not change the coagulation via the TEG analysis.

Comparison of VerifyNow, thromboelastography, and PL-12 in patients with minor ischemic stroke or transient ischemic attack

High on-treatment platelet reactivity (HOPR) is associated with stroke recurrence. It is important to find a reliable method to assess HOPR. We aimed to compare the correlations between VerifyNow™ system, thromboelastography (TEG), and Aggrestar platelet function analyzer (PL-12) on platelet activity in patients with minor ischemic stroke or transient ischemic attack (TIA) after dual antiplatelet therapy for 7 days. About 276 patients were included. Spearman’s correlation coefficient and the kappa coefficient were adopted to evaluate associations among the three test methods. An obvious correlation between VerifyNow and TEG on HOPR-ADP (r=0.64, p<0.001) was found. The correlations of HOPR-ADP between PL-12 and the other two platelet function analyzers were moderate (PL-12 versus VerifyNow, r=0.47, p<0.001; PL-12 versus TEG, r=0.25, p<0.001). The correlations of HOPR-AA were limited among these three platelet function analyzers (VerifyNow versus TEG, r=0.09, p=0.14; VerifyNow versus PL-12, r=0.15, p=0.01; PL-12 versus TEG, r=0.10, p=0.09). Correlations among different platelet function analyzers were varied. VerifyNow and TEG were more correlative than PL-12 on HOPR-ADP. The consistence of HOPR-AA was limited among VerifyNow, TEG and PL-12. The proportion of stroke recurrence and composite events in patients with HOPR-ADP assessing by PL-12 was higher than VerifyNow and TEG.

Characterization of analytical errors in thromboelastography interpretation

Introduction

Interpretation of Thromboelastography (TEG) curve involves correlating patient's clinical profile with TEG parameters and the tracing, keeping in mind the potential sources of errors, and hence requires expertise. We aimed to analyse the analytical errors in TEG interpretation due to paucity of literature in this regard.

Material and methods

The retrospective study was conducted in an apex trauma center in North India. Five months of data was reviewed by two laboratory physicians, with differences resolved by consensus. Cases with pre-analytical errors, missing data and TEG runs lasting <10 ​min were excluded. The analytical errors were classified into: preventable, potentially preventable, non-preventable, and non-preventable but care could have been improved.

Results

Out of 440 TEG tracings reviewed, 70 were excluded. An analytical error was present in 60/370 (16.2%) tracings. There were six types analytical errors, of which, tracings of severe hypocoagulable states showing k-time ​= ​0 (33.3%) was the commonest, followed by tracings with spikes at irregular intervals (30%). Of all the analytical errors, 29/60 (48.2%) were preventable and 5/60 (8.3%) were potentially preventable.

Conclusion

Analytical variables that lead to errors in TEG interpretation were identified in about one-sixth of the cases and almost half of them were preventable. Awareness about the common errors amongst clinicians and laboratory physicians is critical to prevent treatment delay and safeguard patient safety.

Point-of-Care Thromboelastography for Intrathecal Drain Management in Patients With Coagulopathy and Thoracic Aorta Surgery: A Case Report

Spinal drain placement to prevent spinal cord ischemia during thoracic aorta surgery is a necessary yet complex undertaking in patients with coagulopathies. Thromboelastography (TEG) can be used as a point-of-care management tool to monitor coagulation status before drain placement and removal. We present 2 cases: a case of a patient with factor VII deficiency and a case of a patient with thrombocytopenia for whom TEG was an important procedural adjunct during coagulopathy reversal. TEG parameters are also discussed to encourage more frequent TEG use as an adjunct during these complex cases.

Clinical agreement and interchangeability of TEG5000 and TEG6s during cardiac surgery

TEG6s® is a new device introduced by the Haemonetics Corporation and designed to provide the same information as TEG® 5000 (Haemonetics Corporation, Braintree, MA, USA) but with much greater ease of use. We tested whether using citrated TEG6s gave reaction time, maximum amplitude and percentage of clot that had lysed at 30 minutes values similar to a non-citrated TEG5000, to allow clinical interchangeability using our current thrombelastography management algorithm for cardiac surgery. We also examined the agreement between the alpha-angle and functional fibrinogen maximum amplitude in our cardiac surgical patients.

 In total, 243 paired arterial blood samples in 99 patients were tested, using TEG5000 (non-citrated) and TEG6s (citrated) after induction of anaesthesia (prior to heparin administration), following protamine administration at the end of the cardiac bypass and whenever a TEG5000 was requested after this by the attending anaesthetist. Bland–Altman plots and Lin’s concordance coefficient were used to compare agreement whereas modified Bland–Altman plots and McNemar’s test were used to illustrate the differences in management recommendations between the two thrombelastography devices.

 All 243 samples were compared for reaction time and alpha-angle; 239 samples were compared for maximum amplitude; 136 samples were compared for the percentage of clot that had lysed at 30 minutes; 16 samples were compared for functional fibrinogen maximum amplitude. Lin’s concordance coefficient for these parameters was: reaction time 0.63, alpha-angle 0.39, maximum amplitude 0.5, percentage of clot that had lysed at 30 minutes 0.09 and functional fibrinogen maximum amplitude 0.31. Differences between the two devices became more marked at more abnormal values. Significant differences in median values, suggesting a fixed bias, were found for maximum amplitude and functional fibrinogen maximum amplitude. Differences in treatment recommendation could only be calculated for reaction time and maximum amplitude. Maximum amplitude was found to have a significant difference in treatment recommendation between the two devices using our current thrombelastography management algorithm for cardiac surgery with TEG6s recommending treatment in 11.5% more patients than TEG5000.

 Using the TEG6s with our current TEG5000–based thrombelastography management algorithm for cardiac surgery would result in a change in treatment recommendation in at least 10% of our cardiac surgical patients. Agreement between the two thrombelastography devices appears to decrease with increasing patient coagulopathy. New algorithms will need to be developed and tested to validate TEG6s for cardiac surgical patients in our institution.

Characterization of thromboelastography of patients with different pathological types of nephrotic syndrome

To investigate the changes in blood coagulability as measured by thromboelastography (TEG) in patients with nephrotic syndrome of different etiologies as well as in patients with venous thromboembolic events (VTE).From January 2013 to October 2017, patients who were diagnosed as idiopathic membranous nephropathy (IMN), minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) were enrolled into this retrospective study in which their clinical characteristics, including TEG variables, were investigated. According to the presence or absence of VTE, the patients with IMN were divided into 2 groups of VTE and non-VTE. The risk factors of VTE were analyzed with logistic regression.Significant differences in TEG parameters were found among the 3 groups of patients with R and K values lower, while the α-angle, maximum amplitude (MA) and confidence interval (CI) values higher, in the IMN group than those in the MCD and FSGS groups (P < .01). Multiple linear regression analysis indicated that the histologic subtype was an independent relevant factor of K time, angle, MA, and CI values. Multivariate logistic regression analysis revealed that serum albumin and CI value were independent risk factors of VTE (P < .05).The results showed that IMN patients may have higher whole blood coagulability than MCD and FSGS patients. The hypercoagulability in IMN patients may be attributed to platelet hyperactivity and the accelerated fibrin-platelet interaction. Hypoproteinemia and increased CI value were independent risk factors of VTE in IMN.

A droplet-based microfluidic viscometer for the measurement of blood coagulation

A continuous microfluidic viscometer is used to measure blood coagulation. The viscometer operates by flowing oil and blood into a cross section where droplets are generated. At a set pressure, the length of the droplets is inversely proportional to the viscosity of the blood sample being delivered. Because blood viscosity increases during coagulation as the blood changes from a liquid to a solid gel, the device allows to monitor coagulation by simply measuring the drop length. Experiments with swine blood were carried out in its native state and with the addition of coagulation activators and inhibitors. The microfluidic viscometer detected an earlier initiation of the coagulation process with the activator and a later initiation with the inhibitor compared to their corresponding controls. The results from the viscometer were also compared with the clinical method of thromboelastography (TEG), which was performed concurrently for the same samples. The time to initiation of coagulation in the microfluidic viscometer was correlated with the reaction time in TEG. Additionally, the total time for the measurement of clot strengthening in TEG correlated with the time for the maximum viscosity observed in the microfluidic viscometer. The microfluidic viscometer measured changes in viscosity due to coagulation faster than TEG detected the clot formation. The present viscometer is a simple technology that can be used to further study the entire coagulation process.

Selection of Tissue Factor-Deficient Cell Transplants as a Novel Strategy for Improving Hemocompatibility of Human Bone Marrow Stromal Cells

Intravascular transplantation of tissue factor (TF)-bearing cells elicits an instant blood-mediated inflammatory reaction (IBMIR) resulting in thrombotic complications and reduced engraftment. Here we studied the hemocompatibility of commonly used human white adipose tissue (WAT), umbilical cord (UC) and bone marrow stromal cells (BMSC) and devised a possible strategy for safe and efficient stromal cell transplantation.

Methods: Stromal cell identity, purity, and TF expression was tested by RTQ-PCR, flow cytometry and immunohistochemistry. Pro-coagulant activity and fibrin clot formation/stabilization was measured In Vitro by viscoelastic rotational plasma-thromboelastometry and in vivo by injecting sorted human stromal cells intravenously into rats. The impact of TF was verified in factor VII-deficient plasma and by sort-depleting TF/CD142⁺ BMSC.

Results: We found significantly less TF expression by a subpopulation of BMSC corresponding to reduced pro-coagulant activity. UC and WAT stroma showed broad TF expression and durable clotting. Higher cell numbers significantly increased clot formation partially dependent on coagulation factor VII. Depleting the TF/CD142⁺ subpopulation significantly ameliorated BMSC's hemocompatibility without affecting immunomodulation. TF-deficient BMSC did not produce thromboembolism in vivo, comparing favorably to massive intravascular thrombosis induction by TF-expressing stromal cells.

Conclusion: We demonstrate that plasma-based thromboelastometry provides a reliable tool to detect pro-coagulant activity of therapeutic cells. Selecting TF-deficient BMSC is a novel strategy for improving cell therapy applicability by reducing cell dose-dependent IBMIR risk. The particularly strong pro-coagulant activity of UC and WAT preparations sounds an additional note of caution regarding uncritical systemic application of stromal cells, particularly from non-hematopoietic extravascular sources.

Blood clot parameters: Prejudgment of fibrinolysis in thromboelastography

BACKGROUND

Thromboelastography (TEG) is a physical method to simulate the whole process of coagulation and fibrinolysis in the human body environment, and then it also can quickly determine whether patients with hypercoagulable, low coagulation, fibrinolysis or other symptoms. The first step in the diagnosis is based on two parameters: Estimated percentage of lysis (EPL) or the Lysis at 30 min (LY30). These two parameters are used to determine whether the sample has fibrinolysis. However, the determination of LY30 takes a long time, although EPL can reflect real-time fibrinolysis, sometimes the secondary fibrinolysis is not obvious.

MATERIALS AND METHODS

We have an extensive database of results from TEG of fibrinolysis and healthy whole blood (WB). These results were generated using citrated WB, followed by the addition of CaCl₂, to initiate clot formation.

RESULTS

According to the characteristics of fibrinolysis, a new parameter clot retention time (CRT) was proposed to predict the status of fibrinolysis, and the normal range of the parameters was obtained in this paper.

CONCLUSION

It is essential for the clinician to determine the fibrinolytic and ultimately contribute to the treatment of patients. We believe this parameter will add to the standardization of TEG parameters. The new parameter will also shorten the measurement time of non-fibrinolytic samples, which has definite physiological and pathological significance.

ClotChip: A Microfluidic Dielectric Sensor for Point-of-Care Assessment of Hemostasis

This paper describes the design, fabrication, and testing of a microfluidic sensor for dielectric spectroscopy of human whole blood during coagulation. The sensor, termed ClotChip, employs a three-dimensional, parallel-plate, capacitive sensing structure with a floating electrode integrated into a microfluidic channel. Interfaced with an impedance analyzer, the ClotChip measures the complex relative dielectric permittivity, ϵ_r , of human whole blood in the frequency range of 40 Hz to 100 MHz. The temporal variation in the real part of the blood dielectric permittivity at 1 MHz features a time to reach a permittivity peak, , as well as a maximum change in permittivity after the peak, , as two distinct parameters of ClotChip readout. The ClotChip performance was benchmarked against rotational thromboelastometry (ROTEM) to evaluate the clinical utility of its readout parameters in capturing the clotting dynamics arising from coagulation factors and platelet activity. exhibited a very strong positive correlation ( r = 0.99, p < 0.0001) with the ROTEM clotting time parameter, whereas exhibited a strong positive correlation (r = 0.85,  p < 0.001) with the ROTEM maximum clot firmness parameter. This paper demonstrates the ClotChip potential as a point-of-care platform to assess the complete hemostatic process using <10 μL of human whole blood.

Impact of thrombelastography in paediatric intensive care

We assessed the clinical impact of thrombelastography (TEG®) results (TEG® 5000, Haemonetics Corporation, Braintree, MA, USA) by measuring their ability to cause changes in a theoretical treatment plan and contribute to the understanding of haemostasis. We prospectively included paediatric intensive care unit (PICU) patients who had standard tests of haemostasis and TEG ordered and had an arterial catheter or extracorporeal access port in situ. Blood for standard tests and TEG was taken simultaneously. Independent of patient care, general patient information and results of standard laboratory tests were presented to five clinicians who were asked to document their theoretical treatment plan. Clinicians were then shown TEG results and asked if they caused a change in their plan, if they confirmed initial standard laboratory test results, if they enabled a better understanding of haemostasis and if they provided additional information. Inter-rater agreement between the clinicians was determined. Forty-two TEG results were obtained from 34 patients. Overall, the inclusion of TEG results led to a change in treatment plan in 97 of 207 occasions (47%), confirmed standard laboratory test results in 177 of 204 occasions (87%), enabled a better understanding of haemostasis in 140 of 204 occasions (69%) and provided additional information in 131 of 204 occasions (64%). Variation existed between clinicians, seemingly due to individual differences, with poor inter-rater agreement. We conclude that TEG results led to changes in treatment plans almost half the time, confirmed findings of standard tests and provided a better understanding of haemostasis, but randomised controlled trials are required to determine the role and influence of TEG results on patient outcome.

Viscoelastic Monitoring to Guide Hemostatic Resuscitation in Liver Transplantation Surgery

Coagulopathic bleeding must be anticipated during liver transplantation (LT) surgery. Patients with end-stage liver disease (ESLD) often present with disease-related hematologic disturbances, including the loss of hepatic procoagulant and anticoagulant clotting factors and thrombocytopenia. Transplantation surgery itself presents additional hemostatic changes, including hyperfibrinolysis. Viscoelastic monitoring (VEM) is often used to provide targeted, personalized hemostatic therapies for complex bleeding states including cardiac surgery and major trauma. The use in these coagulopathic conditions led to its application to LT, although the mechanisms of coagulopathy in these patients are quite different. While VEM is often used during transplant surgeries in Europe and North America, evidence supporting its use is limited to a few small clinical studies. The theoretical and clinical applications of the standard and specialized VEM assays are discussed in the setting of LT and ESLD.

The impact of early thromboelastography directed therapy in trauma resuscitation

Background

Conventional coagulation tests do not provide an accurate representation of the complex nature of trauma induced coagulopathy. Thrombelastography provides a prompt global overview of all dynamic sequential aspects of trauma induced coagulopathy. The objective of this study was to evaluate the impact of using thrombelastography on blood products utilization, crystalloids utilization, hospital, and intensive care using length of stay, and cost savings.

Methods

We retrospectively reviewed 134 patients (May of 2012 to February of 2015) meeting Class I trauma activation. Outcome data was compared between two groups: patients prior to thrombelastography implementation (n = 87) and patients with thrombelastography guided trauma resuscitation (n = 47). Blood product usage was compared for three time periods: first 4 h, the next 20 h, and first 24 h.

Results

For the first 24 h of treatment, patients with thrombelastography guided trauma resuscitation had lower packed red blood cells (p = 0.0022) and fresh frozen plasma (p = 0.0474), but higher jumbo pack platelets (p = 0.0476) utilization when compared to the patients prior to thrombelastography implementation. There was no statistical significant difference in the utilization of crystalloids for any of the three time intervals. Patients with thrombelastography guided trauma resuscitation had a shorter hospital length of stay (p = 0.0011) and intensive care unit length of stay (p = 0.0059) than the patients prior to thrombelastography implementation. Cost savings in blood products transfusion were most pronounced in patients with penetrating injuries.

Discussion

Using visco-elastic tests to guide blood transfusion was first used for liver transplant patients and then applied to cardiovascular surgery and trauma. Similar to other studies, this study showed using visco-elastic tests for trauma patietns corresponded to an overall reduction in the use of packed red blood cells and fresh frozen plasma during the first 24 hours of resuscitation. In addition, this study showed using visco-elastic tests corresponded to a significant reduction in both hospital and intensive care unit length of stay.

Conclusion

This study demonstrates that Thrombelastography guided trauma resuscitation decreases the overall transfusion requirements of packed red blood cells and fresh frozen plasma. However, given the nature of under-recognized jumbo pack platelets dysfunction in the conventional laboratory parameters, jumbo pack platelets utilization is higher when following Thrombelastography directed resuscitation. The utilization of Thrombelastography corresponded to a reduction in hospital length of stay, intensive care unit length of stay and cost of transfused blood products.

Electronic supplementary material

The online version of this article (10.1186/s13049-017-0443-4) contains supplementary material, which is available to authorized users.

Blood coagulation system in patients with chronic kidney disease: a prospective observational study

OBJECTIVES

Thromboembolic events are the major factor affecting the prognosis of patients with chronic kidney disease (CKD). Haemostatic alterations are possible causes of these complications, but their roles remain poorly characterised. In the prospective observational study, we investigated the entire coagulation process in patients with CKD to elucidate the mechanisms of their high thromboembolic risk.

METHODS

A total of 95 patients with CKD and 20 healthy controls who met the inclusion criteria were consecutively recruited from September 2015 to March 2016. The platelet count, platelet aggregation, von Willebrand factor antigen (vWF:Ag), vWF ristocetin cofactor activity (vWF:RCo), fibrinogen, factor V (FV), FVII, FVIII, antithrombin III, protein C, protein S, D-dimer, standard coagulation tests and thromboelastography were measured in patients with CKD and controls. Associations between the estimated glomerular filtration rate (eGFR) and haemostatic biomarkers were tested using multivariable linear regression.

RESULTS

The adjusted and unadjusted levels of vWF:Ag, vWF:RCo, fibrinogen, FVII, FVIII and D-dimer were significantly higher in patients with CKD than that in the healthy controls, and were elevated with CKD progression. However, after adjustment for baseline differences, platelet aggregation and thromboelastography parameters showed no significant differences between patients with CKD and healthy controls. In the correlation analysis, vWF:Ag, vWF:RCo and FVIII were inversely associated with eGFR (r=-0.359, p<0.001; r=-0.391, p<0.001; r=-0.327, p<0.001, respectively). During the 1-year of follow-up, one cardiovascular event occurred in patients with CKD 5 stage, whereas no thromboembolic event occurred in the CKD 3 and 4 and control groups.

CONCLUSIONS

Patients with CKD are characterised by endothelial dysfunction and increased coagulation, especially FVIII activity. The abnormal haemostatic profiles may contribute to the elevated risk of thrombotic events but further longer-term study with large samples is still required to more precisely determine the relationship between the elevation of procoagulant factors and clinical outcomes.

Thromboelastographic Evaluation of Coagulation in Patients With Liver Disease

BACKGROUND

The aims of this study were to investigate the parameters of thromboelastography (TEG) for evaluating coagulopathy and to reveal an association with disease severity and/or transfusion requirement in patients with chronic liver disease (CLD) in a clinical laboratory setting.

METHODS

We enrolled two groups of adult patients with cirrhotic (N=123) and non-cirrhotic liver disease (N=52), as well as 84 healthy controls. Reaction time (R), kinetic time (K), α-angle (α), maximal amplitude (MA), and coagulation index (CI) were measured with kaolin-activated citrated blood with the TEG 5000 system (Haemonetics Corporation, USA). Platelet count, prothrombin time international normalized ratio (PT INR), albumin, bilirubin, and creatinine were simultaneously measured. The CLD severity was calculated by using the Child-Pugh (C-P) and Model for End-stage Liver Disease (MELD) scores. Transfusion history was also reviewed.

RESULTS

All TEG parameters, PT INR, and platelet count in the cirrhotic group showed significant differences from those in other groups. At least one or more abnormal TEG parameters were identified in 17.3% and 44.7% of patients in the non-cirrhotic and cirrhotic group, respectively. Patients with cirrhotic disease had hypocoagulability. A weak correlation between R and PT INR (r=0.173) was noted. The TEG parameters could not predict CLD severity using the C-P and MELD scores. Patients with normal TEG parameters did not receive transfusion.

CONCLUSIONS

Clinical application of TEG measurements in CLD can be informative for investigating coagulopathy or predicting the risk of bleeding. Further studies are warranted.

Thromboelastrography (TEG) Is Still Relevant in the 21st Century as a Point-of-Care Test for Monitoring Coagulation Status in the Cardiac Surgical Suite

Since their introduction into clinical practice in the early 1960s, viscoelastic point-of-care (POC) testing—thromboelastrography (TEG) and thromboelastrometry (ROTEM)—has become increasingly popular in intensive care units, operating rooms, and emergency room settings. As TEG has been an established POC viscoelastic testing modality for many years, there has been more research and analysis of its utility and ability to reduce transfusions in the general, cardiac, and liver surgical sectors compared with ROTEM. The role of TEG versus ROTEM has been greatly disputed, although both continue to be utilized in the cardiac suite to guide transfusion in cardiac surgery as these procedures produce a profoundly different form of bleeding compared to other surgical interventions.

Flow, Liver, Flow: A Retrospective Analysis of the Interplay of Liver Disease and Coagulopathy in Chronic Subdural Hematoma

BACKGROUND

Chronic subdural hematoma (cSDH) is a common neurosurgical ailment, particularly in elderly patients. A recent study uncovered an association between liver disease and recurrence in patients with cSDH. Here, we explored that relationship to identify recurrence predictors in at-risk patients.

OBJECTIVE

We hypothesized that the association between liver disease and recurrence was attributable to coagulopathy secondary to liver disease.

METHODS

We retrospectively reviewed all patients with cSDH treated with burr-hole drainage by 2 surgeons between 2007 and 2015. Comorbidities and laboratory findings for each patient were examined by Pearson χ² analysis or Mann-Whitney U tests.

RESULTS

We identified 261 cSDH in 215 patients. Patients were a mean age of 65.6 years, and 72% were male. Sixteen patients with cSDH required repeat surgery (6.1%). There were 123 coagulopathic patients (47.1%), and 14 with liver disease (5.4%), all of whom were coagulopathic (P < 0.001). Coagulopathic patients with liver disease were more likely to experience recurrence than patients with coagulopathy alone (relative risk = 4.09, P = 0.019). Patients with liver disease had significantly elevated prothrombin time (P = 0.013) and reduced platelet counts (P < 0.001). Platelets also were reduced in coagulopathic patients with liver disease, as compared with those with coagulopathy alone (P = 0.002). Thrombocytopenia remained significant in a multivariate analysis (P < 0.001).

CONCLUSIONS

Liver disease is significantly associated with the recurrence of cSDH. Although coagulopathy alone does not predict recurrence, patients with coagulopathy and liver disease are at greater risk for recurrence than those with coagulopathy alone. Liver disease effects are reflected in certain hematologic laboratory values.

Correlation of pre-operative plasma protein concentrations in cardiac surgery patients with bleeding outcomes using a targeted quantitative proteomics approach

PURPOSE

Despite recent advancements in the use of thrombelastography (TEG) in the surgical setting, adequate technology to accurately predict bleeding phenotypes for patients undergoing cardiopulmonary bypass on the basis of non-mechanical parameters is lacking. While basic science and translational studies have provided key mechanistic insights about the protein components of coagulation cascades and regulatory mediators of hemostasis and fibrinolysis, targeted protein assays are still missing and the association of protein profiles to bleeding phenotypes and TEG readouts have yet to be discovered.

OBJECTIVE

To identify protein biomarkers of bleeding phenotypes of cardiopulmonary bypass patients in pre-operative plasma.

EXPERIMENTAL DESIGN

We applied a targeted proteomics approach to quantify 123 plasma proteins from 23 patients undergoing cardiopulmonary bypass (CPB) and sternotomy. We then correlated these measurements to bleeding outcomes and TEG parameters, associated with speed of clot formation and strength.

RESULTS

In this pilot study, we demonstrate the feasibility of protein quantitation as a viable strategy to predict low versus high bleeding phenotypes (loss of < or > than 20% of estimated blood volume, calculated as 70 mL/kg for BMI<29.9, 60 mL/kg for BMI = 30-39.9, and 50 mL/kg for BMI>40. Statistical elaborations highlighted a core set of proteins showing significant correlations to either total blood loss or TEG R/MA parameters.

CONCLUSION AND CLINICAL RELEVANCE

Though prospective verification and validation in larger cohorts will be necessary, this report suggests a potential for targeted quantitative proteomics of pre-operative plasma protein concentrations in the prediction of estimated blood loss following CPB.

Thromboelastometry analysis of thrombocytopenic dengue patients: a cross-sectional study

Background

Dengue virus infection (DVI) is a prevalent and potentially fatal viral disease associated with coagulopathy. So far, the coagulation profile of DVI patients with thrombocytopenia has not been assessed through a viscoelastic test such as rotational thromboelastometry. We aimed to describe the prevalence and characteristics of coagulation abnormalities in dengue fever outpatients with thrombocytopenia, addressed by both rotational thromboelastometry and conventional coagulation tests.

Methods

This was a cross-sectional study conducted between April 6^th and May 5^th 2015 in São Paulo, Brazil during a dengue outbreak. Thromboelastometry (ROTEM®) and the conventional coagulation tests prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (aPTT), thrombin time (TT), platelet count and fibrinogen levels were performed in 53 patients with DVI and thrombocytopenia.

Results

Despite a median interquartile range (IQR) platelet count of 77 (63–88) x 10⁹/L in DVI patients, conventional coagulation tests and plasma fibrinogen levels were within the normal range. Subjects demonstrated hypocoagulability in 71.7% (38/53) in INTEM and 54.7% (29/53) in EXTEM DVI patients. FIBTEM analyses detected only 5.7% (3/53) with hypocoagulability among this population. The median (IQR) clotting time (CT), clot formation time (CFT) and maximum clot firmness (MCF) on INTEM were, respectively, 177 (160–207) sec, 144 (108–178) sec and 48 (42–52) mm. On EXTEM, median (IQR) CT, CFT and MCF were, respectively, 69 (65–78) sec, 148 (126–198) sec and 49 (44–55) mm. Median (IQR) MCF on FIBTEM was 15 (13–18) mm.

Conclusion

Thromboelastometry impairment is highly prevalent in DVI patients with thrombocytopenia, particularly in INTEM and EXTEM analyses, while standard coagulation tests are normal in this setting. Clinical implications remain to be established.

Hypercoagulable state evaluated by thromboelastography in patients with idiopathic membranous nephropathy

The aims of this study were to evaluate the characteristics of hypercoagulable states in patients with membranous nephropathy (MN) via thromboelastography (TEG) and to identify risk factors. 235 MN patients who had undergone TEG examinations from 2011 to 2014 were included. An abnormality in at least two TEG parameters is considered a hypercoagulable state. Patient data was compared between the hypercoagulable and non-hypercoagulable groups. Potential risk factors for hypercoagulability were analyzed by logistic regression models. Subgroup analysis was performed in hypercoagulable patients. Compared to the non-hypercoagulable MN patients, the hypercoagulable patients showed a significantly higher proportion of female patients, urinary protein, platelet count, triglyceride and fibrinogen level, along with more severe hypoproteinemia and a reduction of serum antithrombin III. Correlation analysis showed that hypoproteinemia was the primary risk factor for hypercoagulability in MN patients. Among the hypercoagulable MN patients, a subgroup TEG parameter analysis showed that glucocorticoids-used subgroup and smoker subgroup had shortened time to initial fibrin formation (R value) and increased coagulation index respectively (P < 0.05), indicating a more serious hypercoagulable state. Meanwhile, the time to initial fibrin formation (R value) and time to clot formation (K value) of the statin-used patients were remarkably higher than those of the non-statin patients. TEG examinations facilitated the detection of hypercoagulable states in MN patients, and hypoproteinemia was the most important risk factor for hypercoagulability in these patients. The use of glucocorticoids and smoking may help to aggravate hypercoagulable states, while statin drugs may alleviate hypercoagulability.

Monitoring time course of human whole blood coagulation using a microfluidic dielectric sensor with a 3D capacitive structure

This paper reports on the design, fabrication, and testing of a microfluidic sensor for dielectric spectroscopy (DS) of human whole blood during coagulation. The sensor employs a three-dimensional (3D), parallel-plate, capacitive sensing structure with a floating electrode integrated into a microfluidic channel. Using an impedance analyzer and after a 5-point calibration, the sensor is shown to measure the real part of complex relative dielectric permittivity of human whole blood in a frequency range of 10kHz to 100MHz. The temporal variation of dielectric permittivity at 1MHz for human whole blood from three different healthy donors shows a peak in permittivity at ~ 4 to 5 minutes, which also corresponds to the onset of CaCl2-initiated coagulation of the blood sample verified visually.

Heterogeneous phase fibrinolysis rates by damped oscillation rheometry

BACKGROUND

Devices gauging viscoelastic properties of blood during coagulation like the thromboelastograph support fundamental research as well as point of care needs. Associated fibrinolysis data are based on endogenous species or plasminogen activator added to a homogeneous sample prior to clot formation. Digestion in a monolithic structure differs from the physical situation of thrombolytic therapy where surface reactions dominate.

OBJECTIVE

This study aims to develop rheological testing for heterogeneous phase fibrinolysis.

METHOD

Fibrinolysis rates were determined by phase change of a solid clot induced by autologous plasma/streptokinase (SK) in a rheometer sensitive to viscous damping.

RESULTS

Initial slope or overall change in the logarithmic damping factor indicated fibrinolytic rates. Rates depended on clot geometry, phase volumes, clot composition and SK concentration.

CONCLUSION

The damped oscillation rheometer can be adapted to determine relative rates of heterogeneous fibrinolysis in vitro.

An in vitro analysis of the effect of acidosis on coagulation in chronic disease states - a thromboelastograph study

Thrombosis is a complication of many chronic illnesses. Chronic obstructive pulmonary disease (COPD) and diabetes mellitus are common medical conditions frequently associated with a hypercoagulable state. Acidaemia has been shown to reduce coagulation. COPD and diabetes mellitus during acute deterioration can present with a severe acidaemia. The impact of this acidaemia on coagulation is poorly studied. Patients presenting with a diagnosis of diabetic ketoacidosis or type II respiratory failure from COPD and a pH of less than 7.2 were included in our study. A coagulation screen and a thromboelastograph (TEG) were performed on admission and 24 hours later. The mean pH on admission was 7.07 and mean base excess was -16.3. The activated partial thromboplastin time was associated with pH change but remained within the normal range (26-41 s). All other coagulation and TEG parameters failed to show evidence of association (p>0.05). In the two models of non-haemorrhagic acidosis investigated, coagulation was not altered by the changes in pH. More work is needed to understand the complex relationship between factors affecting coagulation in individual disease processes.

Thromboelastography predictive of death in trauma patients

OBJECTIVES

To determine if thromboelastography (TEG) is predictive of patient outcomes following traumatic injury.

METHODS

A retrospective review of 131 patients with pelvic trauma admitted to a Level II trauma center was conducted over four years from 1 January 2009 to 31 December 2012. Patients were identified retrospectively from a prospectively collected database of acute pelvic trauma (n = 372). Eligible patients were identified from billing/coding data as having fractures of the acetabulum, iliac wing or sacral alae. Patients with incomplete TEG data were excluded (n = 241), as were patients with pathological fractures. TEG clotting variables and traditional clotting variables were recorded.

RESULTS

Evaluation of TEG data revealed 41 patients with abnormal clotting times (TEG R). TEG R > 6 was an independent risk factor for death (OR, 16; 95%CI 5.4-53; P = 0.0001). The death rate was 52% in patients with TEG R values ≥6 (n = 13/25). There was no significant association between traditional clotting markers and death rate.

CONCLUSIONS

TEG reaction time value, representing the time of initial clot formation, was the only hematologic marker predictive of mortality in patients with pelvic trauma. Delay in reaction time was associated with a significantly increased death rate, independent of injury severity. The death rate association was not observed with traditional markers of clotting. Future prospective studies may be warranted to determine the presentation and significance of TEG abnormalities when resuscitating patients with orthopaedic trauma.

Acute effects of calcium supplements on blood pressure and blood coagulation: secondary analysis of a randomised controlled trial in post-menopausal women

Recent evidence suggests that Ca supplements increase the risk of cardiovascular events, but the mechanism(s) by which this occurs is uncertain. In a study primarily assessing the effects of various Ca supplements on blood Ca levels, we also investigated the effects of Ca supplements on blood pressure and their acute effects on blood coagulation. We randomised 100 post-menopausal women to 1 g/d of Ca or a placebo containing no Ca. Blood pressure was measured at baseline and every 2 h up to 8 h after their first dose and after 3 months of supplementation. Blood coagulation was measured by thromboelastography (TEG) in a subgroup of participants (n 40) up to 8 h only. Blood pressure declined over 8 h in both the groups, consistent with its normal diurnal rhythm. The reduction in systolic blood pressure was smaller in the Ca group compared with the control group by >5 mmHg between 2 and 6 h (P≤0·02), and the reduction in diastolic blood pressure was smaller at 2 h (between-groups difference 4·5 mmHg, P=0·004). Blood coagulability, assessed by TEG, increased from baseline over 8 h in the calcium citrate and control groups. At 4 h, the increase in the coagulation index was greater in the calcium citrate group compared with the control group (P=0·03), which appeared to be due to a greater reduction in the time to clot initiation. These data suggest that Ca supplements may acutely influence blood pressure and blood coagulation. Further investigation of this possibility is required.

All the bang without the bucks: Defining essential point-of-care testing for traumatic coagulopathy

BACKGROUND

Rapid assessment and treatment of coagulopathy reduces postinjury morbidity and mortality. Although thrombelastography (TEG) may be more accurate and efficient than conventional coagulation tests, it requires significant financial and personnel investments. We hypothesized that point-of-care international normalized ratio (POC INR) may provide a rapid and accurate alternative to TEG.

METHODS

A retrospective review of sequential trauma patients who underwent both POC INR and rapid TEG (r-TEG) testing upon presentation to a Level I trauma center from July 2012 to December 2013 was performed. POC INR was compared with r-TEG values (R value, K time, α angle, maximum amplitude, percent clot lysis in 30 minutes) and transfusion requirements. Vital signs, admission laboratory values, and injury severity were analyzed. POC INR and venous blood gas testing was performed in the emergency department. All results and Pearson correlations noted were significant if p < 0.05.

RESULTS

We identified 628 trauma patients with concomitant r-TEG and POC INR testing. Median Injury Severity Score (ISS) was 13, 20% arrived in shock (base value < -5), 21% were transfused, and 11% died. POC INR correlated with all r-TEG values, with stronger correlations for patients in shock. POC INR and r-TEG had similar correlations with blood products transfused at 4 hours and 24 hours, but only POC INR predicted substantial bleeding and massive transfusion. POC INR also correlated strongly with standard INR testing. POC INR test duration was less than 1 minute, compared with at least 30 minutes for r-TEG. Total cohort charges for POC INR were estimated at $21,980 versus $396,896 for r-TEG.

CONCLUSION

POC INR testing is faster and cheaper than r-TEG. In addition, POC INR correlates not only with r-TEG values but also with acute blood product transfusions. POC INR provides a practical alternative for rapid coagulopathy assessment in the trauma patient at institutions that lack TEG capability.

LEVEL OF EVIDENCE

Diagnostic study, level III. Therapeutic/care management study, level IV.

Development and validation of a new assay for assessing clot integrity

INTRODUCTION

Research and routine laboratory assessment of clot integrity can be time consuming, expensive, and cannot be batched as it is generally performed in real time. To address these issues, we developed and validated a micro-titre based assay to quantify thrombogenesis and fibrinolysis, the purpose being to assess patients at risk of cardiovascular events by virtue of hypercoagulability. In further validation, thrombogenesis results were compared to similar indices from the thrombelastograph (TEG).

METHODS

Our assay determines three indices of thrombogenesis (lag time to the start of thrombus formation (LT), rate of clot formation (RCF), and maximum clot density (MCD)) and two of fibrinolysis (rate of clot dissolution (RCD) and time for 50% of the clot to lyse (T50)). Plasma was tested fresh and again after being frozen at -70°C. Some samples were tested immediately, others after being left at room temperature for up to 24h.

RESULTS

The intra-assay coefficients of variation (CVs) of the three thrombogenesis measures (LT, RCF, MCD) and two fibrinolysis measures (RCD, T50) varied between 2.7 and 12.0% in fresh plasma and between 1.3% and 10.8% in frozen plasma respectively. Similarly, the inter-assay coefficients of variation of the thrombogenesis and fibrinolysis measures were 4.9-10.8% in fresh plasma and 2.2-6.5% in frozen plasma respectively. TEG assays intra- and inter assay CVs were around 25%. There were no significant differences in all plate assay indices up to 6h at room temperature. Certain plate assay thrombogenesis data were comparable to TEG indices after analysis by Pearson's correlation. The reagent processing cost per sample is £15 for TEG and £2 for the plate assays.

CONCLUSION

Our micro-titre based assay assessing plasma thrombogenesis and fibrinolysis has good intra- and inter-assay CVs, can assess plasma up to 6h after venepuncture, is more efficient (in terms of throughput) and is more economical than that of the TEG.

Hypercoagulability following major partial liver resection - detected by thrombomodulin-modified thrombin generation testing

BACKGROUND

Conventional coagulation tests are frequently prolonged after liver surgery, suggesting a post-operative hypocoagulability. However, these tests are unreliable for assessment of the haemostatic status in these patients. In contrast, thrombin generation testing measures the true balance between pro- and anti-coagulant factors.

AIM

To study the perioperative coagulation status in patients undergoing hemi-hepatectomy using thrombin generation assays.

METHODS

We examined thrombin generation profiles in serial plasma samples taken from seventeen patients undergoing right hemi-hepatectomy. Results were compared to ten patients undergoing pancreatic resection and twenty-four healthy volunteers. In addition, we measured conventional coagulation tests and plasma levels of several haemostatic proteins.

RESULTS

Following liver resection, the endogenous thrombin potential (ETP) slightly decreased until post-operative day 7. However, in the presence of thrombomodulin, the ETP increased [from 542 nM*min (417-694) at baseline to 845 nM*min (789-1050) on post-operative day 3] to values higher than that in healthy subjects (558 nM*min (390-680); P < 0.001), which contrasts with substantially prolonged PT levels. Normal to decreased thrombin generation was observed following pancreatic resection. Thrombin generation was only slightly affected by thrombomodulin after hemi-hepatectomy, while thrombin generation in healthy subjects decreased profoundly upon addition of thrombomodulin. This hypercoagulability following liver resection may be explained by decreased levels of protein C, S, and antithrombin and by elevated levels of factor VIII.

CONCLUSIONS

Thrombin generation in the presence of thrombomodulin revealed hypercoagulability in patients following liver resection. These results support the recently advocated restrictive use of plasma during liver resection and the exploration of more extensive use of post-operative thrombosis prophylaxis.