In Normal Controls, Both Age and Gender Affect Coagulability as Measured by Thrombelastography

Comparison of Citrated Whole Blood to Native Whole Blood for Coagulation Testing Using the Viscoelastic Coagulation Monitor (VCM Vet™) in Horses

Viscoelastic monitoring of horse coagulation is increasing due to its advantages over traditional coagulation testing. The use of a point-of-care viscoelastic coagulation monitor (VCM Vet™) has been validated for use in horses using native whole blood (NWB) but has not been assessed using citrated whole blood (CWB), a technique that might have advantages in practicality and precision. Blood was collected from 70 horses, tested in duplicate immediately using NWB (T0), and stored at room temperature as CWB for testing in duplicate at 1 (T1) and 4 (T4) hours after venipuncture for comparison to NWB. Of these horses, 20 were classified as clinically healthy and used to determine reference intervals for CWB at 1 and 4 h post-collection. There were clinically relevant differences in all measured viscoelastic parameters of CWB compared to NWB meaning that they cannot be used interchangeably. These differences were not consistent at T1 and T4 meaning the resting time of CWB influences the results and should be kept consistent. The use of CWB in this study also resulted in more machine errors when compared to NWB resulting in measurements that might not be interpretable.

Increased packed cell volume alters point of care viscoelastic clotting parameters in horses

BACKGROUND

Polycythaemia and coagulopathy are identified risk factors for non-survival in critically ill horses. Assessment of coagulation is recommended for critical care monitoring but may be affected by concurrent polycythaemia.

OBJECTIVE

To evaluate the effects of induced polycythaemia on coagulation parameters as measured by a point-of-care viscoelastic coagulation device (VCM Vet™).

STUDY DESIGN

Prospective interventional study.

METHODS

Healthy adult horses (n = 7) were given 6 mcg/kg of phenylephrine IV over 15 min to induce transient polycythaemia. Samples for packed cell volume (PCV), total solids (TS), complete blood count (CBC), activated partial thromboplastin time (PTT), prothrombin (PT) and VCM Vet™ viscoelastic testing were collected at baseline (T0), 5 min (T1) and 2 h (T2) post-phenylephrine infusion. Splenic volume was measured by transabdominal ultrasonography. VCM Vet™ and plasma-based coagulation parameters, splenic volume and haematologic values were compared within and between time points.

RESULTS

Splenic volume decreased from T0 (11.5 ± 4.8 L) to T1 (6.1 ± 2 L, p = 0.04) and returned to baseline volume by T2 (12.1 ± 3.9 L, p = 0.8), consistent with phenylephrine-induced splenic contraction. PCV increased from T0 (37% ± 4%) to T1 (56.3% ± 5.3%; p < 0.001) and returned to baseline at T2 (41.6% ± 3.6%; p = 0.1). A10 and A20 (amplitude at 10 and 20 min, VCM units) were decreased from T0 (12.6 ± 1.6, 18.9 ± 5) to T1 (5.4 ± 1.9, 7.6 ± 2.4; both p < 0.001) and remained lower than baseline at T2 (9.3 ± 2.1, 12.7 ± 3; both p = 0.01). PT and PTT remained within reference ranges with no significant difference over time (p = 0.5 and 0.09, respectively). PCV was negatively correlated with CFT (R = -0.61, p = 0.003), A10 (R = -0.9, p < 0.001) and A20 (R = -0.87, p < 0.001).

MAIN LIMITATIONS

Small sample size, limited to healthy mares.

CONCLUSIONS

Phenylephrine-induced polycythaemia was associated with hypocoagulable viscoelastic traces using the VCM Vet™ device without effect on plasma-based coagulation assessments or platelet number. Further investigation of viscoelastic testing is needed in horses with increased PCV due to clinical illness.

Histidine-Tryptophan-Ketoglutarate Cardioplegia Yields Different Results in Aortic Valve Surgery Depending on Patient Gender: A Pilot Study

BACKGROUND

Histidine-tryptophan-ketoglutarate (HTK) cardioplegia induces cardiac arrest through membrane hyperpolarization. Aortic valve pathology leads to pathophysiological changes in left ventricular vascularization that may prevent adequate cardioplegic distribution. The objective of the study was to ascertain whether the use of Bretschneider cardioplegia in aortic valve surgery yields different outcomes for male and female patients.

METHODOLOGY

Our study compares the perioperative data of 300 adult patients who underwent aortic valve replacement between June 2023 and June 2024 at the Emergency Cardiac Disease and Transplant Institute, Tîrgu Mures, Romania. Concomitant procedures, age under 18 years, retrograde or combined cardioplegia, and emergency surgery were excluded. The main outcome was operative mortality, and secondary outcomes were postoperative complications and paraclinical data such as ejection fraction and cardiac enzymes.

RESULTS

Male patients comprised 190 (62%) of the sample. The most common age group was 61-70 years in both groups. The mortality rate was 6 (5.4%) for women compared to 9 (4.7%) for men. Preoperative left ventricular ejection fraction was the primary covariate determining 30-day postoperative mortality. Left ventricular ejection fraction decreased by 2.2% in men and 1.1% in women 30 days after surgery.

CONCLUSIONS

The myocardial adaptation to aortic valve pathology exhibits gender-specific differences. However, the utilization of HTK cardioplegia obviates this disparity.

The 2023 WSES guidelines on the management of trauma in elderly and frail patients

BACKGROUND

The trauma mortality rate is higher in the elderly compared with younger patients. Ageing is associated with physiological changes in multiple systems and correlated with frailty. Frailty is a risk factor for mortality in elderly trauma patients. We aim to provide evidence-based guidelines for the management of geriatric trauma patients to improve it and reduce futile procedures.

METHODS

Six working groups of expert acute care and trauma surgeons reviewed extensively the literature according to the topic and the PICO question assigned. Statements and recommendations were assessed according to the GRADE methodology and approved by a consensus of experts in the field at the 10th international congress of the WSES in 2023.

RESULTS

The management of elderly trauma patients requires knowledge of ageing physiology, a focused triage, including drug history, frailty assessment, nutritional status, and early activation of trauma protocol to improve outcomes. Acute trauma pain in the elderly has to be managed in a multimodal analgesic approach, to avoid side effects of opioid use. Antibiotic prophylaxis is recommended in penetrating (abdominal, thoracic) trauma, in severely burned and in open fractures elderly patients to decrease septic complications. Antibiotics are not recommended in blunt trauma in the absence of signs of sepsis and septic shock. Venous thromboembolism prophylaxis with LMWH or UFH should be administrated as soon as possible in high and moderate-risk elderly trauma patients according to the renal function, weight of the patient and bleeding risk. A palliative care team should be involved as soon as possible to discuss the end of life in a multidisciplinary approach considering the patient's directives, family feelings and representatives' desires, and all decisions should be shared.

CONCLUSIONS

The management of elderly trauma patients requires knowledge of ageing physiology, a focused triage based on assessing frailty and early activation of trauma protocol to improve outcomes. Geriatric Intensive Care Units are needed to care for elderly and frail trauma patients in a multidisciplinary approach to decrease mortality and improve outcomes.

Validation of the time to attain maximal clot amplitude after reaching maximal clot formation velocity parameter as a measure of fibrinolysis using rotational thromboelastometry and its application in the assessment of fibrinolytic resistance in septic patients: a prospective observational study: communication from the ISTH SSC Subcommittee on Fibrinolysis

BACKGROUND

In sepsis, fibrinolysis resistance correlates with worse outcomes. Practically, rotational thromboelastometry (ROTEM) is used to report residual clot amplitude relative to maximum amplitude at specified times after clot formation clot lysis indices (CLIs). However, healthy individuals can exhibit similar CLIs, thus making it challenging to solely diagnose the low fibrinolytic state. Furthermore, CLI does not include the kinetics of clot formation, which can affect overall fibrinolysis. Therefore, a more nuanced analysis, such as time to attain maximal clot amplitude after reaching maximal clot formation velocity (t-AUCi), is needed to better identify fibrinolysis resistance in sepsis.

OBJECTIVES

To evaluate the correlation between the degree of fibrinolytic activation and t-AUCi in healthy or septic individuals.

METHODS

Whole blood (n = 60) from septic or healthy donors was analyzed using tissue factor-activated (EXTEM) and nonactivated (NATEM) ROTEM assays. Lysis was initiated with tissue-type plasminogen activator, and CLI and t-AUCi were calculated. Standard coagulation tests and plasma fibrinolysis markers (D-dimer, plasmin-α2-antiplasmin complex, plasminogen activator inhibitor type 1, and plasminogen) were also measured.

RESULTS

t-AUCi values decreased with increasing fibrinolytic activity and correlated positively with CLI for different degrees of clot lysis both in EXTEM and NATEM. t-AUCi cutoff value of 1962.0 seconds in EXTEM predicted low fibrinolytic activity with 81.8% sensitivity and 83.7% specificity. In addition, t-AUCi is not influenced by clot retraction.

CONCLUSION

Whole-blood point-of-care ROTEM analyses with t-AUCi offers a more rapid and parametric evaluation of fibrinolytic potential compared with CLI, which can be used for a more rapid and accurate diagnosis of fibrinolysis resistance in sepsis.

Sex dimorphisms in coagulation: Implications in trauma-induced coagulopathy and trauma resuscitation

Trauma-induced coagulopathy (TIC) is one of the leading causes of preventable death in injured patients. Consequently, it is imperative to understand the mechanisms underlying TIC and how to mitigate this mortality. An opportunity for advancement stems from the awareness that coagulation demonstrates a strong sex-dependent effect. Females exhibit a relative hypercoagulability compared to males, which persists after injury and confers improved outcomes. The mechanisms underlying sex dimorphisms in coagulation and its protective effect after injury have yet to be elucidated. This review explores sex dimorphisms in enzymatic hemostasis, fibrinogen, platelets, and fibrinolysis, with implications for resuscitation of patients with TIC.

INVESTIGATION OF A POINT-OF-CARE VISCOELASTIC COAGULATION MONITOR AND ITS COMPARISON TO THROMBOELASTOGRAPHY IN CLINICALLY HEALTHY AFRICAN ELEPHANTS (LOXODONTA AFRICANA)

Elephant endotheliotropic herpesvirus (EEHV) can induce fatal hemorrhagic disease (HD) in African elephants (Loxodonta africana). Once clinical signs develop, progression is rapid, even with aggressive treatment. There is a critical need to develop point-of-care diagnostic tests to aid in identification of EEHV-HD prior to the onset of overt clinical signs. Study objectives were to investigate a novel, point-of-care viscoelastic coagulation monitor (VCM Vet), compare the results to thromboelastography (TEG), and report traditional hemostatic analytes in adult African elephants. Whole blood was collected from seven clinically healthy elephants (four females and three males, 18-47 yr) and analyzed in duplicate via VCM Vet and kaolin-activated TEG 1-3 and 30 min following collection, respectively. Separated plasma was frozen for ancillary coagulation testing. Both analyses generated quantifiable clotting reactions with variables (median [range]) describing clot formation rate (VCM Vet, clot time = 682 s [530-987 s], clot formation time = 244 s [186-744 s], Alpha = 40° [14-47°]; TEG, reaction time = 6.2 min [3.7-11.8 min], kinetic time = 1.3 min [0.9-2.6 min], Alpha = 70° [57-77°]), clot strength (VCM Vet, maximum clot formation = 34 units [20-45 units]; TEG, maximum amplitude = 75 mm [69-80 mm], shear elastic modulus strength = 14.7 Kdynes/s [11.3-19.5 Kdynes/s]), and clot lysis (VCM Vet, lysis index at 30 min = 100% [100-99%], lysis index at 45 min = 98% [95-100%]; TEG, lysis index at 30 min = 0% [0-0.4%], lysis index at 60 min = 1.4% [0-2.6%]) recorded. Additional testing (median [range]) included D-dimer concentration (33 ng/ml [28-94 ng/ml]), prothrombin time (12.4 s [12.2-13.2 s]), activated partial thromboplastin time (17.2 s [14.2-18.8 s]), and fibrinogen concentration (297 [282-383] mg/dL). Tracings generated by VCM Vet and TEG were clinically similar, and there was visual agreement and minimal difference between quantitative variables for duplicate tests. VCM Vet is a promising, user-friendly tool for use in identification and management of coagulopathies in African elephants.

Native Whole Blood (TRUE-NATEM) and Recalcified Citrated Blood (NATEM) Reference Value Validation with ROTEM Delta

Background: Thromboelastography is a viscoelastic test of whole blood hemostasis. Currently, no reference value exists for native whole blood and recalcified citrated blood without activators. The aim of this study was to compare the results of ROTEM® tests using fresh native blood without decalcification "TRUE-NATEM" with those using decalcified citrated blood "NATEM" and provide reference values for each. Methods: Inclusion criteria were healthy adult volunteers (18-65 years). Exclusion criteria were any medical condition or medication affecting coagulation. Native whole blood testing was defined as "TRUE-NATEM-test." For recalcified citrated blood testing, the NATEM function was used on ROTEM®. Result: The reference value for TRUE-NATEM was CT: 872-1595s, A10: 14-34 mm, A20: 26-48 mm, CFT: 314-839s, MCF: 34-55 mm, and alpha angle: 17-40°. The reference value for NATEM was CT: 757-1327s, A10: 19-43 mm, A20: 33-55 mm, CFT: 219-615s, MCF: 37-61 mm, alpha angle: 24-51°, and ML: 0-3%. When comparing the reference value of NATEM to TRUE-NATEM, the CT and CFT values are decreased and the MCF and alpha angle are increased. The recalcification process of citrated blood in NATEM shows significant activation of coagulation. Female healthy volunteers had enhanced coagulation when activators were used. Age-related statistical difference was seen when activators were used. Ethnicity did not show any difference on the ROTEM values. Conclusion: We determined the reference value for native whole blood and recalcified whole blood using ROTEM®. A significant discrepancy in native whole blood and recalcified citrated blood coagulation was found. Our study underlines the importance of native whole blood as the gold standard reference value in coagulation.

Platelet and cryoprecipitate transfusions from female donors improve coagulopathy in vitro

BACKGROUND

Females are relatively hypercoagulable compared with males, with increased platelet aggregation and improved clot dynamics. However, sex differences in coagulation have not yet been considered in transfusion guidelines. Therefore, our objective was to evaluate hemostatic differences in sex concordant and sex discordant cryoprecipitate and platelet transfusions. We hypothesized that transfusion of blood products from female donors results in improved coagulopathy compared with male blood products.

METHODS

This was a cohort study evaluating sex dimorphisms in coagulation assays and clotting factors in healthy volunteer plasma and cryoprecipitate. Sex dimorphisms in transfusions were evaluated using an in vitro coagulopathy model. Female or male platelets or single-donor cryoprecipitate was added to "recipient" whole blood after dilution of recipient blood with citrated saline to provoke a coagulopathic profile. Citrated native thromboelastography was then performed. Liquid chromatography/mass spectroscopy was performed on single-donor cryoprecipitate to evaluate sex dimorphisms in the proteome of cryoprecipitate.

RESULTS

Females have an increased proportion of functional fibrinogen. Transfusion of female-donor platelets and cryoprecipitate induces a larger decrease in R time and greater increase in angle than male-donor platelets or cryoprecipitate. Female-donor cryoprecipitate has increased factor V and factor XIII compared with male cryoprecipitate, and comprehensive proteomics revealed sex differences in several proteins with potential immunological significance.

CONCLUSION

Platelets and cryoprecipitate from female donors improve coagulopathy more than male blood products in vitro. Increased factor V and factor XIII activity as well as increased fibrinogen activity in female donors appears to drive this disparity. Sex differences in the proteome of cryoprecipitate may influence how transfusions modulate the thromboinflammation of trauma. The differing hemostatic profiles of female and male blood products suggest the potential role of sex-specific transfusions guidelines in hemostatic resuscitation.

What Proportion of Patients With Musculoskeletal Tumors Demonstrate Thromboelastographic Markers of Hypercoagulability? A Pilot Study

BACKGROUND

Thromboelastography (TEG) is a point-of-care venipuncture test that measures the elasticity and strength of a clot formed from a patient's blood, providing a more comprehensive analysis of a patient's coagulation status than conventional measures of coagulation. TEG includes four primary markers: R-time, which measures the time to clot initiation and is a proxy for platelet function; K-value, which measures the time for said clot to reach an amplitude of 20 mm and is a proxy for fibrin cross-linking; maximum amplitude (MA), which measures the clot's maximum amplitude and is a proxy for platelet aggregation; and LY30, which measures the percentage of clot lysis 30 minutes after reaching the MA and is a proxy for fibrinolysis. Analysis of TEG-derived coagulation profiles may help surgeons identify patient-related and disease-related factors associated with hypercoagulability. TEG-derived coagulation profiles of patients with musculoskeletal oncology conditions have yet to be characterized.

QUESTIONS/PURPOSES

(1) What TEG coagulation profile markers are most frequently aberrant in patients with musculoskeletal oncology conditions presenting for surgery? (2) Among patients with musculoskeletal oncology conditions presenting for surgery, what factors are more common in those with TEG-defined hypercoagulability? (3) Do patients with musculoskeletal oncology conditions with preoperative TEG-defined hypercoagulability have a higher postoperative incidence of clinically symptomatic venous thromboembolism (VTE) than those with a normal TEG profile?

METHODS

In this retrospective, pilot study, we analyzed preoperatively drawn TEG assays on 52 patients with either primary bone sarcoma, soft tissue sarcoma, or metastatic disease to bone who were scheduled to undergo either tumor resection or nail stabilization. Between January 2020 and December 2021, our orthopaedic oncology service treated 410 patients in total. Of these, 13% (53 of 410 patients) had preoperatively drawn TEG assays. TEG assays were collected preincision as part of a division initiative to integrate the assay into a clinical care protocol for patients with primary bone or soft tissue sarcoma or metastatic disease to bone. Unfortunately, failures to adequately communicate this to our anesthesia colleagues on a consistent basis resulted in a low overall rate of assay draws from eligible patients. One patient on therapeutic anticoagulation preoperatively for the treatment of active VTE was excluded, leaving 52 patients eligible for analysis. We did not exclude patients taking prophylactic antiplatelet therapy preoperatively. All patients were followed for a minimum of 6 weeks postoperatively. We analyzed factors (age, sex, tumor location, presence of metastases, and soft tissue versus bony disease) in reference to hypercoagulability, defined as a TEG result indicating supranormal clot formation (for example, reduced R-time, reduced K-value, or increased MA). Patients with clinical concern for deep vein thrombosis (DVT) (typically painful swelling of the affected extremity) or pulmonary embolism (typically by dyspnea, tachycardia, and/or chest pain) underwent duplex ultrasonography or chest CT angiography, respectively, to confirm the diagnosis. Categorical variables were analyzed via a Pearson chi-square test and continuous variables were analyzed via t-test, with significance defined at α = 0.05.

RESULTS

Overall, 60% (31 of 52) of patients had an abnormal preoperative TEG result. All abnormal TEG assay results demonstrated markers of hypercoagulability. The most frequent aberration was a reduced K-value (40% [21 of 52] of patients), followed by reduced R-time (35% [18 of 52] of patients) and increased MA (17% [9 of 52] of patients). The mean ± SD TEG markers were R-time: 4.3 ± 1.0, K-value: 1.2 ± 0.4, MA: 66.9 ± 7.7, and LY30: 1.0 ± 1.2. There was no association between hypercoagulability and tumor location or metastatic stage. The mean age of patients with TEG-defined hypercoagulability was higher than those with a normal TEG profile (44 ± 23 years versus 59 ± 17 years, mean difference 15 [95% confidence interval (CI) 4 to 26]; p = 0.01). In addition, female patients were more likely than male patients to demonstrate TEG-defined hypercoagulability (75% [18 of 24] of female patients versus 46% [13 of 28] of male patients, OR 3.5 [95% CI 1 to 11]; p = 0.04) as were those with soft tissue disease (as opposed to bony) (77% [20 of 26] of patients with soft tissue versus 42% [11 of 26] of patients with bony disease, OR 4.6 [95% CI 1 to 15]; p = 0.01). Postoperatively, symptomatic DVT developed in 10% (5 of 52; four proximal DVTs, one distal DVT) of patients, and no patients developed symptomatic pulmonary embolism. Patients with preoperative TEG-defined hypercoagulability were more likely to be diagnosed with symptomatic postoperative DVT than patients with normal TEG profiles (16% [5 of 31] of patients with TEG-defined hypercoagulability versus 0% [0 of 21] of patients with normal TEG profiles; p = 0.05). No patients with normal preoperative TEG profiles had clinically symptomatic VTE.

CONCLUSION

Patients with musculoskeletal tumors are at high risk of hypercoagulability as determined by TEG. Patients who were older, female, and had soft tissue disease (as opposed to bony) were more likely to demonstrate TEG-defined hypercoagulability in our cohort. The postoperative VTE incidence was higher among patients with preoperative TEG-defined hypercoagulability. The findings in this pilot study warrant further investigation, perhaps through multicenter collaboration that can provide a sufficient cohort to power a robust, multivariable analysis, better characterizing patient and disease risk factors for hypercoagulability. Patients with TEG-defined hypercoagulability may warrant a higher index of suspicion for VTE and careful thought regarding their chemoprophylaxis regimen. Future work may also evaluate the effectiveness of TEG-guided chemoprophylaxis, as results of the assay may inform selection of antiplatelet versus anticoagulant agent.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Children and Snakebite: Snake Venom Effects on Adult and Paediatric Plasma

Snakebite is a globally neglected tropical disease, with coagulation disturbances being the primary pathology of many deadly snake venoms. Age-related differences in human plasma have been abundantly reported, yet the effect that these differences pose regarding snakebite is largely unknown. We tested for differences in coagulotoxic effects (via clotting time) of multiple snake venoms upon healthy human adult (18+) and paediatric (median 3.3 years old) plasma in vivo and compared these effects to the time it takes the plasmas to clot without the addition of venom (the spontaneous clotting time). We tested venoms from 15 medically significant snake species (from 13 genera) from around the world with various mechanisms of coagulotoxic actions, across the three broad categories of procoagulant, pseudo-procoagulant, and anticoagulant, to identify any differences between the two plasmas in their relative pathophysiological vulnerability to snakebite. One procoagulant venom (Daboia russelii, Russell's Viper) produced significantly greater potency on paediatric plasma compared with adult plasma. In contrast, the two anticoagulant venoms (Pseudechis australis, Mulga Snake; and Bitis cornuta, Many-horned Adder) were significantly more potent on adult plasma. All other procoagulant venoms and all pseudo-procoagulant venoms displayed similar potency across both plasmas. Our preliminary results may inform future studies on the effect of snake venoms upon plasmas from different age demographics and hope to reduce the burden of snakebite upon society.

Estradiol provokes hypercoagulability and affects fibrin biology: A mechanistic exploration of sex dimorphisms in coagulation

BACKGROUND

Sex dimorphisms in coagulation are well established, with female-specific hypercoagulability conferring a survival benefit in the setting of trauma-induced coagulopathy (TIC). The mechanism behind these phenomena remains to be elucidated. We hypothesize that estradiol provokes a hypercoagulable profile and alters clot proteomics and fibrin crosslinking.

METHODS

Whole blood was collected from healthy adult volunteers (n = 30). A battery of thrombelastography (TEG) assays (native, kaolin, platelet-mapping, functional fibrinogen), whole blood thrombin generation, proteomics, and clot structure architecture (via analysis of fibrin crosslinks and fluorescent fibrinogen-visualized clots) were performed after pre-treatment of the blood with physiologic concentrations of beta-estradiol. In addition, a prospective study of coagulation through the menstrual cycle was conducted by collecting blood from women on peak and nadir estrogen days in the standard 28-day menstrual cycle.

RESULTS

On TEG, in females, estradiol provoked a hypercoagulable phenotype, specifically a shorter time to clot formation and greater thrombin generation, greater rate of clot propagation and functional fibrinogen, higher clot strength, and diminished clot fibrinolysis. In both males and females, estradiol increased platelet hyperactivity. Similar changes were seen in time to clot formation and clot strength in vivo during peak estrus of the menstrual cycle. On proteomic analysis, in both males and females, estradiol was associated with increases in abundance of several procoagulant and antifibrinolytic proteins. Crosslinking mass spectrometry analysis showed addition of estradiol increased the abundance of several FXIII crosslinks within the FIBA alpha chain in both sexes. Fluorescent fibrinogen analysis revealed a trend toward increased fiber resolvability index after addition of estradiol.

CONCLUSION

Estradiol provokes a hypercoagulable phenotype, affecting time to clot formation, clot propagation, clot strength, clot fibrinolysis, and clot structure. In sum, these data highlight the role of estradiol is driving female-specific hypercoagulability and highlights its potential role as a therapeutic adjunct in resuscitation of TIC.

Point-of-care viscoelastic coagulation assessment in healthy dogs during the perianesthetic period

Background

The viscoelastic coagulation monitor (VCM Vet) is a novel, portable device that provides a global assessment of hemostasis. The study aims were to evaluate serial viscoelastic analysis during the perianesthetic period in healthy dogs and to compare the agreement between two VCM Vet devices. Twenty healthy dogs undergoing orthopedic surgery were enrolled. Whole blood samples were collected from an intravenous catheter at four time points: baseline, 15 min after premedication, 60 min after inhalant initiation, and 60 min after inhalant termination. Viscoelastic tests were performed in duplicate on different devices, providing: clot time (CT; seconds), clot formation time (CFT; seconds), alpha angle (α; degrees), amplitude (units) at 10 (A10) and 20 (A20) minutes post clot time, maximum clot firmness (MCF; units), and lysis index (%) at 30 (Li30) and 45 (Li45) minutes post maximum clot formation.

Results

One hundred sixty samples were analyzed. The speed of CT and CFT significantly decreased an average of 25.5 s (95% confidence interval [CI]15.9–35.0) and 6.9 s (95% CI 3.1–10.7) per time point, respectively. There were no significant changes in clot strength or lysis variables. The Bland–Altman style plot shows an acceptable rate of agreement for all variables with intra-class correlation ranging from 0.64–0.94.

Conclusion

The rate of clot formation (CT and CFT) decreased over the perianesthetic period in healthy dogs undergoing surgery. These changes were small and occurred without changes in clot strength or fibrinolysis rate, thus were not clinically relevant. There was clinically acceptable consistency between devices.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03442-x.

Massive Bleeding After Surgical Repair in Acute Type A Aortic Dissection Patients: Risk Factors, Outcomes, and the Predicting Model

Background

Massive bleeding throughout aortic repair in acute type A aortic dissection (ATAAD) patients is a common but severe condition that can cause multiple serious clinical problems. Here, we report our findings regarding risk factors, short-term outcomes, and predicting model for massive bleeding in ATAAD patients who underwent emergent aortic repair.

Methods

A universal definition of perioperative bleeding (UDPB) class 3 and 4 were used to define massive bleeding and comprehensively evaluate patients. A total of 402 consecutive patients were enrolled in this retrospective study during 2019. Surgical strategies used to perform aortic arch procedures included total arch and hemiarch replacements. In each criterion, patients with massive bleeding were compared with remaining patients. Multivariable regression analyses were used to identify independent risk factors for massive bleeding. Logistic regression was used to build the model, and the model was evaluated with its discrimination and calibration.

Results

Independent risk factors for massive bleeding included male sex (OR = 6.493, P &lt; 0.001), elder patients (OR = 1.029, P = 0.05), low body mass index (BMI) (OR = 0.879, P = 0.003), emergent surgery (OR = 3.112, P = 0.016), prolonged cardiopulmonary bypass time (OR = 1.012, P = 0.002), lower hemoglobin levels (OR = 0.976, P = 0.002), increased D-dimer levels (OR = 1.000, P = 0.037), increased fibrin degradation products (OR = 1.019, P = 0.008), hemiarch replacement (OR = 5.045, P = 0.037), total arch replacement (OR = 14.405, P = 0.004). The early-stage mortality was higher in massive bleeding group (15.9 vs. 3.9%, P = 0.001). The predicting model showed a well discrimination (AUC = 0.817) and calibration (χ2 = 5.281, P = 0.727 &gt; 0.05).

Conclusion

Massive bleeding in ATAAD patients who underwent emergent aortic repair is highly associated with gender, emergent surgery, increased D-dimer levels, longer CPB time, anemia, and use of a complex surgical strategy. Since massive bleeding may lead to worse outcomes, surgeons should choose suitable surgical strategies in patients who are at a high risk of massive bleeding.

Gender Differences in the Outcomes of Cardiogenic Shock Requiring Percutaneous Mechanical Circulatory Support

There is evidence for the lower use of percutaneous mechanical circulatory support (pMCS) in women. We aimed to determine (1) whether gender differences exist regarding in-hospital mortality, hospital course, and procedures; (2) whether socio-demographic and treatment-related factors were associated with these differences. Using the National Inpatient Sample, we collected the International Classification of Diseases, Ninth Revision, Clinical Modification codes for cardiogenic shock (CS) because of acute myocardial infarction AMI or acutely decompensated advanced heart failure and included intra-aortic balloon pump, Impella or Tandem Heart percutaneous ventricular assist devices (pVADs), extracorporeal membrane oxygenation. Demographics, co-morbidities, in-hospital course and procedures were recorded, and the Charlson Co-morbidity Index was calculated. Multivariable hierarchical logistic regression analysis and additional sensitivity analyses were performed. We identified 376,116 cases of CS because of acute myocardial infarction or acutely decompensated advanced heart failure, of which 113,305 required pMCS. Women were more likely to be older, non-White, insured by Medicare, and have a higher burden of co-morbidities and higher Charlson Co-morbidity Index. pMCS devices were inserted in 35,516 women (24.9%) and 77,789 men (33.3%). Women were less likely to receive pVAD or pulmonary artery (PA) catheters. Blood transfusions and acute respiratory failure were more common in women than men. Women had 15% higher in-hospital mortality and in a multivariate analysis, women, older age, having no insurance, diabetes mellitus, chronic kidney disease, cerebrovascular disease, peripheral arterial disease, longer time to pMCS insertion, receiving PA catheter, pVAD or extracorporeal membrane oxygenation and having cardiac arrest were associated with higher in-hospital mortality. In conclusion, women requiring pMCS support had a higher co-morbidity load, in-hospital mortality, acute respiratory failure, blood transfusions, and lower PA catheter use. Studies addressing early gender-specific interventions in CS are needed to reduce these differences.

Thromboelastography-Based Evaluation of Gender-Associated Hypercoagulability

BACKGROUND

Age, race, and gender differences in coagulation status of healthy volunteers have been reported in previous case series; however, rigorous multivariate analysis adjusting for these factors is lacking. We aimed to investigate the effects of age, race, and gender on baseline coagulation status in healthy volunteers.

METHODS

Thirty healthy volunteer controls with no history of bleeding or thrombotic events and no previous anticoagulant or antiplatelet use were recruited. Citrated and heparinized blood samples were drawn, and kaolin and platelet-mapping thromboelastography (TEG) assays performed.

RESULTS

Thirty participants had a mean age of 37, mean body mass index of 29 kg/m², and were 47% African-American and 70% female. Women were significantly older than men (40 ± 11 y vs 28 ± 7 y, P = .002); there were no significant differences in demographics by race. Multivariate analysis of variance for the effect of age, race, and gender across TEG parameters yielded evidence for gender differences in hypercoagulability (Pillai's trace P = .02), which appear to be driven by differences in K-time, alpha angle, maximal amplitude, and G parameter. Women were hypercoagulable compared to men, as manifested by shorter K-time, steeper alpha angle, higher maximal amplitude, and larger G parameter.

DISCUSSION

Women at baseline have relatively hypercoagulable fibrin deposition kinetics, platelet contributions to clot formation, and overall clot strength compared to men, even when adjusted for age and race. Additional research is needed to specifically detail the key patient-level factors, clinical implications, and opportunities for tailored therapy related to gender-associated hypercoagulability.

Coagulation status in patients with pulmonary embolism receiving long-term anticoagulant therapy

Aim. To study the blood coagulation status by various laboratory methods in patients after pulmonary embolism (PE) receiving long-term anticoagulant therapy.

Material and methods. The blood of 23 patients with pulmonary embolism, who received long-term anticoagulant therapy, was studied. The study of coagulation profile, D-dimer, thrombodynamics, thromboelastography and thrombin generation test were carried out.

Results. The thrombin generation test shows a significant increase in the time of its formation, while the maximum amount of thrombin formed is half that of the reference values. There is a slightly increased median fibrin clot growth rate in the thrombodynamics test — 30,4 gm/min with a normal coagulation rate of 20-29 gm/min. The result of thromboelastography also reflects the blood hypocoagulation, in terms of R, Angle a and CI.

Conclusion. Integral methods for assessing the thrombotic readiness in combination with a routine coagulation panel demonstrate a complete picture of blood coagulation potential in patients after pulmonary embolism requiring long-term anticoagulant therapy.

Global coagulation assays in hypercoagulable states

Thrombosis is one of the major global causes of morbidity and mortality, and predicting the risk of thrombotic and cardiovascular complications remains one of the key challenges in modern medicine. Conventional coagulation testing does not provide sufficient information, primarily because they measure the time to start of blood clotting and do not evaluate total thrombin generation. Possible adjunctive tools that may be helpful are global coagulation assays, which includes the assessment of the final products of the coagulation cascade, namely thrombin and fibrin. Whilst these assays have been more widely investigated in bleeding states, their role in thrombotic disorders is less established. We have previously investigated the use of assays such as thromboelastography, calibrated automated thrombogram and overall haemostatic potential assay in several hypercoagulable states including cardiovascular disease, haematological disorders and influence of hormone status as well as healthy controls. We provide a review of the use and limitations of global coagulation assays in healthy controls as well as hypercoagulable conditions.

Rotational thromboelastometry (ROTEM® ) in gestational diabetes mellitus and coagulation in healthy term pregnancy: A prospective observational study in Australia

BACKGROUND

Rotational thromboelastometry (ROTEM^® ) is a point-of-care test of coagulation. ROTEM^® -defined hypercoagulability has been identified in pregnant women and in non-pregnant patients with diabetes mellitus. Pregnancy is known to be a hypercoagulable state, but the influence of gestational diabetes mellitus (GDM) on coagulation is unknown.

AIM

The aim of this study was to assess the combined effect of pregnancy and GDM on coagulation using ROTEM^® and to compare this to healthy pregnant women presenting for elective caesarean delivery.

MATERIALS AND METHODS

Ethics approval was granted for recruitment of women presenting for elective caesarean delivery. Women with pre-existing conditions affecting coagulation were excluded. Group N included health pregnant women at term and Group G included pregnant women at term with GDM. Data regarding GDM management and glycaemic control were collected. Poor glycaemic control was defined by markers of accelerated fetal growth and elevated fasting or postprandial blood glucose levels. The ROTEM^® parameters (extrinsically activated thromboelastometric test (EXTEM) / fibrin polymerisation test (FIBTEM) amplitude at five minutes, coagulation time, maximum clot firmness and clot formation time) were compared between the two groups using Student's t-test.

RESULTS

There were 75 women in Group N and 21 women in Group G. Mean age and median body mass index values were comparable for both groups. There were no statistical differences found between the EXTEM and FIBTEM parameters analysed for the two groups.

CONCLUSIONS

There was no association between GDM and increased hypercoagulability as demonstrated by ROTEM^® parameters in healthy pregnant women presenting for elective caesarean delivery at term.

Does Gender Matter: A Multi-Institutional Analysis of Viscoelastic Profiles for 1565 Trauma Patients With Severe Hemorrhage

BACKGROUND

Viscoelastic tests including thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are being used in patients with severe hemorrhage at trauma centers to guide resuscitation. Several recent studies demonstrated hypercoagulability in female trauma patients that was associated with a survival advantage. The objective of our study was to elucidate the effects of gender differences in TEG/ROTEM values on survival in trauma patients with severe hemorrhage.

METHODS

A retrospective review of consecutive adult patients receiving massive transfusion protocol (MTP) at 7 Level I trauma centers was performed from 2013 to 2018. Data were stratified by gender and then further examined by TEG or ROTEM parameters. Results were analyzed using univariate and multi-variate analyses.

RESULTS

A total of 1565 patients were included with 70.9% male gender (n = 1110/1565). Female trauma patients were older than male patients (43.5 ± .9 vs 41.1 ± .6 years, P = .01). On TEG, females had longer reaction times (6.1 ± .9 min vs 4.8 ± .2 min, P = .03), increased alpha angle (68.6 ± .8 vs 65.7 ± .4, P < .001), and higher maximum amplitude (59.8 ± .8 vs 56.3 ± .4, P < .001). On ROTEM, females had significantly longer clot time (99.2 ± 13.7 vs 75.1 ± 2.6 sec, P = .09) and clot formation time (153.6 ± 10.6 sec vs 106.9 ± 3.8 sec, P < .001). When comparing by gender, no difference for in-hospital mortality was found for patients in the TEG or ROTEM group (P > .05). Multivariate analysis showed no survival difference for female patients (OR 1.11, 95% CI .83-1.50, P = .48).

CONCLUSIONS

Although a difference between male and females was found on TEG/ROTEM for certain clotting parameters, no difference in mortality was observed. Prospective multi-institutional studies are needed.

Platelet and White Cell Reactivity to Top-Load Intravenous Perfluorocarbon Infusion in Healthy Sheep

BACKGROUND

Perfluorocarbon emulsions (PFCs) are intravenous artificial oxygen carriers with enhanced gas solubility. As lipid micelle nanoparticle emulsions, PFCs may have a class effect that causes degrees of thrombocytopenia. Understanding the extent of the platelet effects, including mechanism and potential inflammation after PFC infusion, is important for safe human trials.

METHODS

Normal sheep (Dorper) were infused with 5 mL/kg of Oxygent (w/v 60% PFC) or Perftoran (w/v 20% PFC). Controls received 6% Hetastarch or were naive. Blood samples were analyzed from baseline, time 0 (the end of infusion), 3 and 24 hours, and 4 and 7 days. Platelet count, plateletcrit, mean platelet volume, platelet distribution width, and CD-62p (a platelet activation-dependent membrane protein) were measured. Neutrophils, monocytes, and total white blood cell counts were analyzed.

RESULTS

In these inflammatory cell lines, there were no consistent changes or cellular activation after PFC infusion. A decrease (<10% from baseline and naive controls) in platelet count was seen on day 4 after Oxygent infusion (3 g/kg), which recovered by day 7. No platelet effect was seen in Perftoran (1 g/kg). Plateletcrit, mean platelet volume, and platelet distribution width did not change significantly at any time point among the groups. CD-62p, ADP, and collagen aggregometry showed no significant change in platelet function.

CONCLUSION

There was no evidence of overall reduction in platelet number, or any correlation with the change in platelet activation or inhibition. Therefore, the risk of increased thrombosis/bleeding after PFC intravenous infusion is low in this non-trauma sheep model.

Hypercoagulability in pregnant trauma patients

Circulating hormones affect coagulopathy in pregnancy and after trauma. The hemostatic profile of pregnant women after injury has not been characterized. We hypothesized that injured pregnant females would present with an initial thrombelastography (TEG) reflecting a more hypercoagulable profile and a higher incidence of venous thromboembolic events (VTE) when compared with non-pregnant females and males.

Hypercoagulability as Measured by Thrombelastography May Be Associated with the Size of Acute Ischemic Infarct-A Pilot Study

Background: Thromboelastography (TEG^®) measures coagulation function in venous blood. Previous studies have reported that this device providing an integrated data on dynamics of clot formation may be useful for predicting clinical outcome in ischemic stroke. We investigated whether a hypercoagulability detected by thrombelastography may be associated with larger size of acute ischemic infarct. Methods: We included 40 ischemic stroke subjects with large artery atherosclerosis or small-vessel disease to a cross-sectional pilot study. Thrombelastography parameters related to time of clot formation (R- reaction time, K-clot kinetics), clot growth and strengthening (angle-alpha and MA-maximum amplitude) and lysis (Ly30) were performed within first 24 h after the onset of stroke. A volume of ischemic infarct was assessed on the basis of diffusion-weighted imaging (DWI) sequence of magnetic resonance imaging. Results: In the entire group, we reported that subjects with a large ischemic focus (>2 cm³) had a higher diameter of a clot (measured as MA) than subjects with a small ischemic focus (p = 0.0168). In the large artery atherosclerosis subgroup, we showed a significant correlation between MA and size of acute infarct (R = 0.64, p = 0.0138), between angle (alpha) and size of acute infarct (R = 0.55, p = 0.0428) and stroke subjects with hypercoagulability (MA > 69 mm) had significantly higher probability of a larger size of acute ischemic focus compared to normalcoagulable subjects (5.45 cm³ vs. 1.35 cm³; p = 0.0298). In multivariate logistic regression hypercoagulability was a predictor of a large size of ischemic infarct (Odds ratio OR = 59.5; 95% confidence interval (CI) 1.08–3558.8; p = 0.0488). Conclusions: We emphasized that thrombelastography, based on the parameters related to clot strength, may have clinical utility to identify the risk of the extensive ischemic infarct.

Endovascular Hepatic Artery Stents in the Modern Management of Postpancreatectomy Hemorrhage

Background

Postoperative hemorrhage is a potentially lethal complication of pancreatoduodenectomy. This study reports on the use of endovascular hepatic artery stents in the management of postpancreatectomy hemorrhage.

Methods

This is a retrospective analysis of a prospectively maintained, consecutive dataset of 440 patients undergoing pancreatoduodenectomy over 68 months. Data are presented on bleeding events and outcomes, and contextualized by the clinical course of the denominator population. International Study Group of Pancreatic Surgery terminology was used to define postpancreatectomy hemorrhage.

Results

Sixty-seven (15%) had postoperative hemorrhage. Fifty (75%) were male and this gender difference was significant (P = 0.001; 2 proportions test). Postoperative pancreatic fistulas were more frequent in the postoperative hemorrhage group (P = 0.029; 2 proportions test). The median (interquartile range [IQR]) delay between surgery and postoperative hemorrhage was 5 days (2-14 days). Twenty-six (39%) required intervention comprising reoperation alone in 12, embolization alone in 5, and endovascular hepatic artery stent deployment in 5. Four further patients underwent more than 1 intervention with 2 of these having stents. Endovascular stent placement achieved initial hemostasis in 5 of 7 (72%). Follow-up was for a median (IQR) of 199 days (145-400 days) poststent placement. In 2 patients, the stent remained patent at last follow-up. The remaining 5 stents occluded with a median (IQR) period of proven patency of 10 days (8-22 days).

Conclusions

This study shows that in the specific setting of postpancreatoduodenectomy hemorrhage with either a short remnant gastroduodenal artery bleed or a direct bleed from the hepatic artery, where embolization risks occlusion with compromise of liver arterial inflow, endovascular hepatic artery stent is an important hemostatic option but is associated with a high risk of subsequent graft occlusion.

Global coagulation assays in healthy controls: are there compensatory mechanisms within the coagulation system?

Global coagulation assays (GCAs) may provide a more comprehensive individual hemostatic profiling. We aim to evaluate GCAs (thromboelastography, thrombin generation) in healthy controls, and correlate results with age, gender, lipid status, tissue factor pathway inhibitor (TFPI) and P-selectin. Blood samples were collected from healthy controls (> 18 years of age) not taking anticoagulation or antiplatelet agents and without known cardiovascular disease. Thromboelastography (TEG) was performed on citrated whole blood while calibrated automated thrombogram (CAT), P-selectin (endothelial marker) and TFPI (principle inhibitor of tissue factor-initiated coagulation) were performed on platelet-poor plasma. 153 healthy controls (mean age 42 years, 98 females (64%)) were recruited. Female controls demonstrated more hypercoagulable TEG and CAT parameters while those over 50 years of age demonstrated more hypercoagulable TEG parameters despite comparable thrombin generation. Paradoxically, individuals with "flattened" thrombin curves (lower velocity index (rate of thrombin generation) despite preserved endogenous thrombin potential (amount of thrombin)) were more likely to be male (49% vs 20%, p = 0.003) with increased low-density lipoprotein cholesterol (3.3 vs 2.6 mmol/L, p = 0.003), P-selectin (54.2 vs 47.3 ng/mL, p = 0.038) and TFPI (18.7 vs 8.6 ng/ml, p = 0.001). In addition to reduced velocity index and thrombin peak, controls in the highest TFPI tertile also demonstrated a poorer lipid profile. GCAs can detect subtle changes of the hemostatic profile. Interestingly, reduced thrombin generation was paradoxically associated with increased cardiovascular risk factors, possibly attributable to increased TFPI. This finding may suggest compensation by the coagulation system in response to endothelial activation and represent a biomarker for early cardiovascular disease. A larger prospective study evaluating these assays in the cardiovascular disease population is ongoing.

Factors associated with excessive bleeding following elective on-pump coronary artery bypass grafting

INTRODUCTION

Excessive bleeding following cardiac surgery is associated with worse outcomes. We aimed to analyze preoperative and operative factors associated with excessive bleeding in coronary artery bypass patients to better understand which patients are under increased risk.

METHODS

The study was conducted as an observational study in a tertiary center for cardiac surgery by retrospective analysis of the hospital database. Patients were grouped according to chest tube output within the postoperative 24 h. Patients in the 4th percentile of chest tube output per kilogram were categorized as having excessive bleeding. Patients with excessive bleeding were compared with the other patients for preoperative and operative factors. Factors significant in univariate analysis were carried onto the multivariate analysis.

RESULTS

Patients with excessive bleeding were more likely to be males (91.4% vs. 78.7%, p = .002), have lower body mass index (BMI) (27.4 vs. 29.2, p < .001), and low platelets (6.9% vs. 1.5%, p = .006). Cardiopulmonary bypass (101.8 vs. 110.9 min, p = .022) time was longer in the excessive bleeding group. Patients with excessive bleeding were more likely to have more than three vessels revascularized. Male sex, lower BMI, low platelets, and longer cardiopulmonary bypass time were independently associated with increased bleeding.

CONCLUSION

Male sex, lower BMI, low platelet count, and longer cardiopulmonary bypass time are associated with extensive bleeding after elective coronary artery bypass surgery (CABG). Patients with higher bleeding risk should be identified preoperatively to account for adverse outcomes after CABG.

Simulated Hypergravity Activates Hemostasis in Healthy Volunteers

Background

Hypergravity may promote human hemostasis thereby increasing thrombotic risk. Future touristic suborbital spaceflight will expose older individuals with chronic medical conditions, who are at much higher thromboembolic risk compared with professional astronauts, to hypergravity. Therefore, we tested the impact of hypergravity on hemostasis in healthy volunteers undergoing centrifugation.

Methods and Results

We studied 20 healthy seated men before and after 15 minutes under 3 Gz hypergravity on a long‐arm centrifuge. We obtained blood samples for hemostasis testing before, immediately after, and 30 minutes after centrifugation. Tests included viscoelastic thromboelastometry, platelet impedance aggregometry, endothelial activation markers, blood rheology testing, microparticle analyses, and clotting factor analysis. Exposure to hypergravity reduced plasma volume by 12.5% (P=0.002) and increased the red blood cell aggregation index (P<0.05). With hypergravity, thrombelastographic clotting time of native blood shortened from 719±117 seconds to 628±89 seconds (P=0.038) and platetet reactivity increased (P=0.045). Hypergravity shortened partial thromboplastin time from 28 (26–29) seconds to 25 (24–28) seconds (P<0.001) and increased the activity of coagulation factors (eg, factor VIII 117 [93–134] versus 151 [133–175] %, P<0.001). Tissue factor concentration was 188±95 pg/mL before and 298±136 pg/mL after hypergravity exposure (P=0.023). Antithrombin (P=0.005), thrombin‐antithrombin complex (P<0.001), plasmin‐alpha2‐antiplasmin complex (0.002), tissue‐plasminogen activatior (P<0.001), and plasminogen activator inhibitor‐1 (P=0.002) increased with centrifugation. Statistical adjustment for plasma volume attenuated changes in coagulation.

Conclusions

Hypergravity triggers low‐level hemostasis activation through endothelial cell activation, increased viscoelasticity, and augmented platelet reactivity, albeit partly counteracted through endogenous coagulation inhibitors release. Hemoconcentration may contribute to the response.

Coagulopathy in elderly patients with coronavirus disease 2019

BACKGROUND

Since the outbreak of coronavirus disease 2019 (COVID-19), clinical features have been analyzed in detail. However, coagulopathy in elderly COVID-19 patients has been scarcely reported.

METHODS

Coagulation parameters of 189 patients with COVID-19 in Tongji hospital were retrospectively analyzed among age groups.

RESULTS

Patients were divided into 2 groups: older group (≥65 years, n = 87) and younger group (<65 years, n = 102). The proportion of patients with elevated fibrinogen (79.0% vs 59.6%, p = .005) and D-dimer (78.0% vs 55.2%, p = .001) shows the significant difference between the groups. The elderly patients revealed significantly longer prothrombin time (14.0 [13.4-14.4]s vs 13.6 [13.2-14.1]s, p = .026), higher D-dimer (1.00 [0.5-1.9] μg/mL vs 0.6 [0.3-1.6] μg/mL, p = .013) and fibrinogen (5.2 [4.1-6.2] g/L vs 4.4 [3.4-5.7] g/L, p = .004) levels, compared to the younger group. A positive correlation was observed between the coagulation parameters and inflammatory markers including high-sensitivity C-reactive protein and interleukin-6 (p < .05).

CONCLUSIONS

The hypercoagulable state is more common in elderly COVID-19 patients, and coagulopathy is associated with excessive systemic inflammation.

Utility of Thromboelastography to Identify Hypercoagulability in Lung Cancer Related Ischemic Stroke Patients

Lung cancer related hypercoagulability could increase the risk of ischemic stroke. Routine coagulation tests may have limited capacity in evaluating hypercoagulability. The aim of this study was to investigate the ability of thromboelastography (TEG) in the identification of hypercoagulability in patients with lung cancer and cryptogenic ischemic stroke (LCIS). Between January 2016 and December 2018, whole citrated blood from LCIS patients (n = 35) and age- and gender-matched lung cancer patients and healthy volunteers were used for TEG and routine coagulation tests. The coagulation indicator and clinical data were compared among the 3 groups. There were 27/35 (77.14%) on TEG and 18/35 (51.43%) on routine coagulation tests of LCIS patients who had evidence of hypercoagulability. The detection rate of hypercoagulability by TEG in LCIS patients was higher than routine coagulation tests (P = 0.018). Comparing with lung cancer patients and healthy controls, LCIS patients have a significantly higher maximum amplitude (MA), fibrinogen, and D-dimer. Multivariate analysis showed that D-dimer and MA were significantly associated with ischemic stroke in lung cancer patients. ROC curve showed that the area under the curve of TEG (0.790 ± 0.048, 95% CI: 0.697-0.864) was significantly higher than routine coagulation tests (0.673 ± 0.059, 95% CI: 0.572-0.763) (P = 0.04) in identifying hypercoagulability in LCIS patients. Therefore, TEG could identify hypercoagulability in LCIS patients and healthy controls. Identification of hypercoagulability in lung cancer patients by TEG may be helpful to prevent the occurrence of LCIS.

Establishment of thromboelastography reference intervals by indirect method and relevant factor analyses

Thromboelastography (TEG) as a global coagulation test has been continuously developed for many decades in either research or clinical practice. The versatility of TEG test leads to difficulty in standardization and result interpretation. Reference intervals (RIs) of TEG may be one of the most controversial factors that influence its wide applications. RIs establishment with the traditional method is time‐consuming and laborious as well as beyond general laboratory capability. Indirect method using stored data and with statistical calculation and small cost is emerging as an alternative approach for RIs determination. Gender, age, or both affect RIs and must be taken into account before RIs estimation. The present study retrospectively collected a total of 930 TEG results as subjects and established RIs with indirect method for Kaolin‐activated TEG, including the parameters of R, K, αAngle, MA, and CI. Furthermore, gender, age, and gender‐dependent age subsets analyses were performed to determine their effects on RIs of TEG. In this study, we found that TEG parameters showed more hypercoagulability in female than male, most of the measured TEG variables were significantly associated with aging, but only in male statistical significance was found among different age stratification and 60‐year‐old could be considered as cutting point to differentiate coagulation ability in male. In addition, RIs of TEG were estimated by indirect method suitably and verified to be valid in our study. Finally, the RIs of TEG by indirect method were basically significantly different to the RIs recommended by manufacturer, but the consistent percentage is relatively high in the most of measured parameters. In conclusion, it is suggestive that the indirect method for RIs establishment is feasible, but relevant factors, such as gender and age, specifically gender‐dependent age effect, should be considered before RIs determinations.

Severity of Anaemia Has Corresponding Effects on Coagulation Parameters of Sickle Cell Disease Patients

Sickle cell disease (SCD) is an inherited condition characterized by chronic haemolytic anaemia. SCD is associated with moderate to severe anaemia, hypercoagulable state and inconsistent platelet count and function. However, studies have yielded conflicting results with regards to the effect of anaemia on coagulation in SCD. The purpose of this study was to determine the effect of anaemia severity on selected coagulation parameters of SCD patients. Four millilitres of venous blood samples were taken from the participants (SCD and non-SCD patients) and used for analysis of full blood count and coagulation parameters. Data was analysed using SPSS version-16. From the results, it was seen that individuals with SCD had a prolonged mean PT, APTT and high platelet count compared to the controls. There was also significant difference in the mean PT (p = 0.039), APTT (p = 0.041) and platelet count (p = 0.010) in HbSS participants with severe anaemia. Mean APTT also showed significant difference (p = 0.044) with severe anaemia in HbSC participants. It can be concluded that SCD patients have prolonged PT, APTT and increased platelet count which might predispose them to bleeding episodes and thrombocytosis. Significant difference was also seen between severity of anaemia and mean PT, APTT and platelet count in HbSS individuals.

Comparison of thromboelastography versus conventional coagulation tests in simulated Crotalus atrox envenomation using human blood

INTRODUCTION

Pit viper bites are a source of significant morbidity and mortality. Pit viper bites can cause venom-induced consumptive coagulopathy (VICC), typically evaluated with laboratory-based conventional coagulation tests (CCTs). However, CCTs require a laboratory and average 1 h to conduct. Thromboelastography (TEG) provides real-time, point-of-care tests of coagulation that are fast and require no separate laboratory facilities, which could be advantageous in both hospital and austere settings. However, the relative efficacy of TEG versus CCTs was unclear, particularly at low venom concentrations. Therefore, the objectives of this study were to test human blood with various concentrations of pit viper venom using CCTs and TEG to determine dose-dependent changes, lowest observed effect concentration (LOEC), and sensitivity to detecting samples out of normal diagnostic range.

METHODS

Blood samples from 20 volunteers were mixed with varying concentrations of western diamond back rattlesnake (Crotalus atrox) venom based on the mouse LD50_IV (none, 0.5%, 1%, 2%, 33%, 66%, and 100% LD50_IV). Samples were split and assessed with both CCTs including prothrombin time (PT), international normalized ratio (INR), partial thromboplastin time (PTT), fibrinogen, and D-dimer, along with TEG measures of reaction time (R), kinetic time (K), rate of clot formation (α-angle), and clot strength (MA). Data were analyzed as dose-dependent concentration-based changes in raw values and in percent of samples exceeding diagnostic thresholds using ANOVA and nonparametric statistics at the p < .05 threshold.

RESULTS

All evaluations showed significant concentration-dependent changes, and 100% of samples exceeded diagnostic thresholds at 33%LD50_IV and above, save D-dimer. At 0.5%LD50_IV, R, K, α-angle, PT, and INR were significantly different from controls, and at 1%LD50_IV, mean values exceeded diagnostic thresholds for R, K, α-angle, MA, PT, and INR, but not for PTT, D-dimer, or fibrinogen. At 2%LD50_IV, 100% of samples were out of normal range for K, α-angle, and PT_. CONCLUSION: TEG is effective in coagulopathy evaluations of in vitro simulated pit viper envenomation. At low venom concentrations, TEG performed as well or better than the majority of CCTs. These findings provide empirical evidence supporting the use of TEG to rapidly and accurately evaluate VICC.

A Possible Role of Amyloidogenic Blood Clotting in the Evolving Haemodynamics of Female Migraine-With-Aura: Results From a Pilot Study

Introduction: Migraine is a debilitating primary headache disorder with a poorly understood aetiology. An extensive body of literature supports the theory of migraine as a systemic vascular inflammatory disorder characterised by endothelial dysfunction. It is also well-known that chronic inflammation results in an excessive burden of oxidative stress and therefore cellular dysfunction. In this study the effects of excessive oxidative stress through the phases of female migraine-with-aura (FMA) were evaluated by examining the health of the systems of haemostasis.

Methods: Blood was obtained from 11 FMA patients at baseline and during the headache phase of migraine, as well as from 8 healthy age-matched female controls. Samples were analysed using thromboelastography (TEG) to evaluate viscoelastic profiles, light microscopy for erythrocyte morphology, Scanning Electron Microscopy (SEM) for erythrocyte and fibrin clot structure, confocal microscopy for β-amyloid detection in fibrin clots.

Results: Viscoelastic profiles from platelet poor plasma showed decreased clot reaction times in FMA at baseline (95% CI [5.56, 8.41]) vs. control (95% CI [7.22, 11.68]); as well as decreased time to maximum thrombus generation for the same comparison (95% CI [6.78, 10.20] vs. [8.90, 12.96]). Morphological analysis of erythrocytes indicated widespread macrocytosis, poikilocytosis and eryptosis in the migraineurs. Analysis of fibrin networks indicated that this hypercoagulability may be a result of aberrant fibrin polymerisation kinetics caused by the adoption of a β-amyloid conformation of fibrin(ogen).

Conclusion: The results reaffirm the hypercoagulable state in migraine, and would suggest that this state is most likely a result of a systemic inflammatory state which induces oxidative damage to both erythrocytes and fibrin(ogen) in female episodic migraine-with-aura. Furthermore, if the amylodogenic changes to fibrin(ogen) were observed in a larger cohort, this would support theories of micro-embolisation in migraine-with-aura.

Female platelets have distinct functional activity compared with male platelets: Implications in transfusion practice and treatment of trauma-induced coagulopathy

BACKGROUND

Females are hypercoagulable and have survival benefit in trauma-induced coagulopathy (TIC). The mechanism for this sex-specific hypercoagulability is unknown. Platelets and platelet function are central in providing hemostatic potential and are the largest contributor to clot strength. Ligands (adenosine diphosphate [ADP] and platelet-activating factor [PAF]) bind distinct platelet receptors to potentiate activation and aggregation. We hypothesize that female platelets have a differential response to ADP and PAF, resulting in greater aggregation and activation compared to males, and that estradiol pretreatment of male or female platelets enhances this activity.

METHODS

Platelets were collected from healthy volunteers: premenopausal/postmenopausal females (≤54 years, >54 years) and similarly aged males. Platelet aggregometry and flow cytometry (fibrinogen binding capacity) were examined. After treatment with ADP or PAF, platelet aggregation was assessed with Chronolog and activation assessed by CD41 receptor surface expression using flow cytometry. Aggregation and activation were again assessed after platelet pretreatment with estradiol.

RESULTS

Healthy volunteers included 12 premenopausal and 13 postmenopausal females and 18 similarly aged males. Female platelets (combined premenopausal and postmenopausal) had increased aggregation with ADP stimulation, as compared to male platelets. Male and female platelets had differential fibrinogen receptor expression, with female platelets (combined premenopausal and postmenopausal) demonstrating robust activation with ADP versus male platelets with PAF. In the presence of estradiol incubation, male platelets' activation with PAF approximated that of females (combined premenopausal and postmenopausal) and activation with PAF was enhanced in both male and female platelets.

CONCLUSION

Male and female platelets have differential response to stimuli, suggesting sex-dependent signaling and cellular activation. Female platelets have both increased aggregation and activation potential, and estradiol pretreatment feminizes male platelets to approximate female platelet activation with PAF. These findings offer potential explanation for sex-based differences in hemostatic potential in TIC and question whether donor sex of transfused platelets should be considered in resuscitation. Estradiol may also serve as a novel therapeutic adjunct in TIC.

Prospective assessment of fibrinolysis in morbid obesity: tissue plasminogen activator resistance improves after bariatric surgery

BACKGROUND

Morbid obesity is associated with an increased risk of thrombotic events, which has been attributed to increased thrombotic activity. Multiple mechanisms have been proposed to explain this increased risk, including an inflammatory state with upregulation of procoagulant and antifibrinolytic proteins. We therefore hypothesize that patients with morbid obesity are hypercoagulable and will revert to normal after bariatric surgery.

OBJECTIVES

To evaluate changes in the hypercoagulable state after bariatric surgery.

SETTING

University Hospital, Bariatric Center of Excellence, United States.

METHODS

Thromboelastography (TEG) data were collected on 72 subjects with morbid obesity, with 36 who had 6 months of follow-up after bariatric surgery. TEG data of 75 healthy subjects (HS) without obesity, recent trauma or surgery, acute infection, or chronic conditions (e.g., liver, cardiovascular, or kidney disease; cancer; diabetes; autoimmune or inflammatory disorders; and disorders of coagulation) were used for comparison. TEG was performed alone and with the addition of 75 and 150 ng/mL tissue plasminogen activator (tPA) to quantify fibrinolysis resistance (tPA-challenged TEG).

RESULTS

The bariatric surgery cohort had a median age of 40.5 years, a median body mass index of 44.6 kg/m², and 90% female patients. Median body mass index reduced significantly 6 months post surgery but remained elevated compared with the HS group (31.4 versus 25.4 kg/m², P < .0001). At 6 months post surgery, subjects had longer reaction time (mean difference, 1.3; P = .02), lower maximum amplitude (-2.4, P = .01), and increased fibrinolysis with low-dose (3.1, P < .0001) and high-dose tPA-challenged TEG (9, P < .0001). Compared with HS, the postsurgery TEG values were still more likely to be abnormal (all P < .05).

CONCLUSIONS

Patients with morbid obesity form stronger clots more rapidly and are more resistant to fibrinolysis than subjects without obesity. Bariatric surgery significantly improved the hypercoagulable profile and fibrinolysis resistance of morbid obesity.

Sex-based differences in transfusion need after severe injury: Findings of the PROPPR study

BACKGROUND

Women are underrepresented in trauma research, and aggregated results of clinical trials may mask effects that differ by sex. It is unclear whether women respond differently to severe hemorrhage compared with men. We sought to evaluate sex-based differences in outcomes after severe trauma with hemorrhage.

METHODS

We performed a secondary analysis of the Pragmatic Randomized Optimal Platelet and Plasma Ratios trial. Trauma patients predicted to require massive transfusion were randomized to a 1:1:1 vs 1:1:2 plasma to platelet to red blood cell transfusion ratio. Analysis was performed according to sex, controlling for clinical characteristics and transfusion arm.

RESULTS

A total of 134 women and 546 men were analyzed. In multivariable analysis, there was no difference in mortality at 24 hours (hazard ratio for women 0.64, 95% confidence interval 0.34-1.23, P = .18) or in time to hemostasis (hazard ratio 1.10, 95% confidence interval 0.84-1.42, P = .49) by sex. We observed no difference between sexes in volume of blood products transfused during active hemorrhage. However, after anatomic hemostasis, women received lower volumes of all products, with a 38% reduction in fresh frozen plasma (mean ratio 0.62 (95% confidence interval 0.43-0.89, P = .01), 49% reduction in platelets (mean ratio 0.51, 95% confidence interval 0.33-0.79, P < .01) and 49% reduction in volume of red blood cells (mean ratio 0.51, 95% confidence interval 0.33-0.79, P < .01).

CONCLUSION

Mortality and time to hemostasis of trauma patients with hemorrhage did not differ by sex. Although there was no difference in transfusion requirement during active hemorrhage, once hemostasis was achieved, women received fewer units of all blood products than men. Further research is required to determine whether women exhibit differences in coagulation during and after severe traumatic hemorrhage.

Trauma Resuscitation Consideration: Sex Matters

BACKGROUND

Sex dimorphisms in coagulation have been recognized, but whole blood assessment of these dimorphisms and their relationship to outcomes in trauma have not been investigated. This study characterizes the viscoelastic hemostatic profile of severely injured patients by sex, and examines how sex-specific coagulation differences affect clinical outcomes, specifically, massive transfusion (MT) and death. We hypothesized that severely injured females are more hypercoagulable and therefore, have lower rates of MT and mortality.

STUDY DESIGN

Hemostatic profiles and clinical outcomes from all trauma activation patients from 2 level I trauma centers were examined, with sex as an experimental variable. As part of a prospective study, whole blood was collected and thrombelastography (TEG) was performed. Coagulation profiles were compared between sexes, and association with MT and mortality were examined. Poisson regression with robust standard errors was performed.

RESULTS

Overall, 464 patients (23% female) were included. By TEG, females had a more hypercoagulable profile, with a higher angle (clot propagation) and maximum amplitude (MA, clot strength). Females were less likely to present with hyperfibrinolysis or prolonged activating clotting time than males. In the setting of depressed clot strength (abnormal MA), female sex conferred a survival benefit, and hyperfibrinolysis was associated with higher case-fatality rate in males.

CONCLUSIONS

Severely injured females have a more hypercoagulable profile than males. This hypercoagulable status conferred a protective effect against mortality in the setting of diminished clot strength. The mechanism behind these dimorphisms needs to be elucidated and may have treatment implications for sex-specific trauma resuscitation.

Factors associated with the increased bleeding in the postoperative period of cardiac surgery: A cohort study

AIMS AND OBJECTIVES

To identify factors associated with the increased bleeding in patients during the postoperative period after cardiac surgery.

BACKGROUND

Bleeding is among the most frequent complications that occur in the postoperative period after cardiac surgery, representing one of the major factors in morbidity and mortality. Understanding the factors associated with the increased bleeding may allow nurses to anticipate and prioritise care, thus reducing the mortality associated with this complication.

DESIGN

Prospective cohort study.

METHODS

Adult patients in a cardiac hospital who were in the postoperative period following cardiac surgery were included. Factors associated with the increased bleeding were investigated by means of linear regression, considering time intervals of 6 and 12 hr.

RESULTS

The sample comprised 391 participants. The factors associated with the increased bleeding in the first 6 hr were male sex, body mass index, cardiopulmonary bypass duration, anoxia duration, metabolic acidosis, higher heart rate, platelets and the activated partial thromboplastin time in the postoperative period. Predictors in the first 12 hr were body mass index, cardiopulmonary bypass duration, metabolic acidosis, higher heart rate, platelets and the activated partial thromboplastin time in the postoperative.

CONCLUSIONS

This study identified factors associated with the increased postoperative bleeding from cardiac surgery that have not been reported in previous studies. The nurse is important in the vigilance, evaluation and registry of chest tube drainage and modifiable factors associated with the increased bleeding, such as metabolic acidosis and postoperative heart rate, and in discussions with the multiprofessional team.

RELEVANCE TO CLINICAL PRACTICE

Knowledge of the factors associated with the increased bleeding is critical for nurses so they can provide prophylactic interventions and early postoperative treatment when needed.

In vitro investigation of the effects of exogenous sugammadex on coagulation in orthopedic surgical patients

Background

Previous studies have shown that sugammadex resulted in the prolongation of prothrombin time and activated partial thromboplastin time. In this study, we aimed to investigate the in vitro effects of exogenous sugammadex on the coagulation variables of whole blood in healthy patients who underwent orthopedic surgery.

Methods

The effects of sugammadex on coagulations were assessed using thromboelastography (TEG) in kaolin-activated citrated blood samples taken from 14 healthy patients who underwent orthopedic surgery. The in vitro effects of three different concentrations of sugammadex (42, 193, and 301 μg mL^− 1) on the TEG profiles were compared with those of the control (0 μg mL^− 1). Previous studies indicated that these exogenous concentrations correspond to the approximate maximum plasma concentrations achieved after the administration of 4, 16, and 32 mg kg^− 1 sugammadex to healthy subjects.

Results

Increased sugammadex concentrations were significantly associated with reduced coagulation, as evidenced by increases in reaction time (r), coagulation time, and time to maximum rate of thrombus generation (TMRTG), and decreases in the angle, maximum amplitude, and maximum rate of thrombus generation. Compared with the control, the median percentage change (interquartile range) in the TEG values of the samples treated with the highest exogenous sugammadex concentration was the greatest for r, 53% (26, 67.3%), and TMRTG, 48% (26, 59%).

Conclusions

This in vitro study suggests that supratherapeutic doses of exogenous sugammadex might be associated with moderate hypocoagulation in the whole blood of healthy subjects.

Trial registration

identifier: UMIN000029081, registered 11 September 2017.

Gender related issues in thrombosis and hemostasis

INTRODUCTION

Many aspects of hemostasis, both primary and secondary, as well as fibrinolysis display sex differences. From a clinical viewpoint, certain differential phenotypic presentations clearly arise within various disorders of thrombosis and hemostasis. Areas covered: The present mini-review summarizes selected clinical entities where sex differences are reflected in both frequency and clinical presentation of hemostasis disorders. Sex differences are discussed within the settings of cardiovascular disease, including coronary artery disease and ischemic stroke, venous thromboembolism and inherited bleeding disorders. Moreover, pregnancy and labor present particular challenges in terms of increased thromboembolic and bleeding risk, and this is also summarized. Expert commentary: Available knowledge on sex differences in risk factors and clinical presentation of disorders within thrombosis and hemostasis is increasing. However, more evidence is needed to further clarify different risk factors and treatment effect in men and women, both as regards to cardiovascular disease and venous thromboembolism. This should facilitate improved gender guided risk stratification, and prevention and treatment of these diseases. Finally, risk assessment during pregnancy remains a challenge; this applies both to thromboembolic risk assessment during normal pregnancy and special care of women with inherited bleeding disorders during labor.

Does sex matter? Effects on venous thromboembolism risk in screened trauma patients

BACKGROUND

Sex is associated with disparate risk of venous thromboembolism (VTE) in nontrauma patients, with increased risk seen during pregnancy and in women on hormone-containing medications. Sex effects on VTE after trauma are unclear. Some studies have demonstrated no effect whereas others have instead shown a higher incidence of VTE among men. We hypothesized that male sex would increase the risk of VTE across all age groups in trauma patients undergoing standardized duplex screening.

METHODS

All admissions to a Level I academic trauma center 2000 to 2014 were reviewed. We excluded patients for age <18 years, pregnancy, pre-admission anticoagulant use, and hospital length of stay (LOS) <72 hours. A strict venous duplex screening protocol was followed. Female patients were subcategorized into pre- and post-menopausal groups based on age (18-44 vs. ≥ 55 years). Bivariate analysis and logistic regression were used to identify variables correlating with VTE risk.

RESULTS

A total of 8,726 patients met inclusion criteria. The overall VTE rate was 5.3%. Bivariate analysis did not find a difference in VTE risk by sex (5.1% women vs. 5.4% men, p = 0.565), or between women and men within age-defined menopausal categories (pre-menopausal women 3.9% vs. men 4.7%, p = 0.293; post-menopausal women 5.9% vs. men 7.0%, p = 0.22). Logistic regression (see figure) did identify other risk factors for VTE including age ≥55 (adjusted odds ratio [AOR] 2.0), increasing ISS (AOR 1.5-2.1), penetrating mechanism of injury (AOR 2.2), lower extremity injury (AOR 1.7), need for mechanical ventilation (AOR 2.1), and increasing hospital length of stay (LOS 7-28 days, AOR 3.8; LOS > 28 days, AOR 9.1).

CONCLUSION

There was no difference in VTE rates based on patient sex, even after controlling for menopausal status. Aggressive VTE screening of over 8,700 patients did identify several other patient populations at increased risk of developing VTE. More intensive VTE prophylaxis may be appropriate in these patients.

LEVEL OF EVIDENCE

Epidemiologic study, level III; therapeutic study, level V.

Blood transfusion and coagulopathy in geriatric trauma patients

Background

Trauma resuscitation has undergone a paradigm shift with new emphasis on the early use of blood products and increased proportions of plasma and platelets. However, it is unclear how this strategy is applied or how effective it is in the elderly population. The study aim is to identify differences in transfusion practices and the coagulopathy of trauma in the elderly.

Methods

Data was prospectively collected on all consecutive patients that met trauma activation criteria at a Level I trauma centre. Data fields included patient demographics, co-morbidities, injury and resuscitation data, laboratory values, thromboelastography (TEG) results, and outcome measures. Elderly patients were defined as those 55 and older. Propensity-score matched analysis was completed for patients receiving blood product transfusion. Patients were matched by gender, mechanism, injury severity score (ISS), head injury, and time from injury.

Results

Total of 628 patients were included, of which 142 (23%) were elderly. Elderly patients were more likely to be female (41% vs. 24%), suffer blunt mechanism of trauma (96% vs. 80%), have higher ISS scores (mean 25.4 vs. 21.6) and mortality (19% vs. 8%). Elderly patients were significantly more likely to receive a blood transfusion (42% vs. 30%), specifically for red cells and plasma. Propensity-matched analysis resulted in no difference in red cell transfusion or mortality. Despite the broad similarities between the matched cohorts, trauma coagulopathy as measured by TEG was less commonly observed in the elderly.

Discussion

Our results suggest that elderly trauma patients are more likely to receive blood products when admitted to a trauma centre, though this may be attributed to under-triage. The results also suggest an altered coagulopathic response to traumatic injury which is partially influenced by increased anticoagulant and antiplatelet medication use in the geriatric population.

Conclusion

It is not clear whether the acute coagulopathy of trauma is equivalent in geriatric patients, and further study is therefore warranted.

Thromboelastometry and Thrombelastography Analysis under Normal Physiological Conditions - Systematic Review

BACKGROUND

Studies investigating thromboelastometry or thrombelastography analyses in a physiological context are scattered and not easy to access.

OBJECTIVE

To systematically retrieve and describe published reports studying healthy subjects and targeting at the correlation of ROTEM® and TEG® measurements with conventional parameters of hemostasis.

METHODS

Systematic Review: Papers were searched in Medline, Scopus and the Science Citation Index database. Reference lists of included studies and of reviews were screened. To be included papers had to report ROTEM or TEG data on healthy subjects. Two reviewers screened papers for inclusion, read full texts of potentially relevant papers, and extracted data of included papers.

RESULTS

Searches identified 1,721 records of which 1,713 were either excluded immediately or after reading the full text. The remaining 8 studies enrolled 632 subjects. The association of conventional parameters of hemostasis with ROTEM and with TEG was investigated in one and two studies, respectively. Overall correlation was limited and ranged from 0.0 to 0.40 (total thrombus generation vs. fibrinogen; clotting time INTEM vs. activated partial thromboplastin time).

CONCLUSIONS

Studies assessing the relationship between thromboelastometry or thromboelastography analyses and conventional parameters of hemostasis in healthy subjects remains scarce, and correlations are limited. Further research is needed to understand the physiology of thromboelastometry and thromboelastography parameters.

Reference values for kaolin-activated thromboelastography in volunteers of Anhui Province in China

BACKGROUND

The assessment of the coagulation status using thromboelastography (TEG) in Chinese population has less been reported. This study aimed to establish reliable reference values for kaolin-activated TEG in Chinese volunteers.

METHODS

A total of 1681 Chinese adult individuals were recruited for this study. The reference individuals were stratified by gender and age, and the TEG values were measured on the basis of strict quality control. The 95% reference values were determined using nonparametric statistical methods.

RESULTS

The sex-related 95% reference values were reaction time (R):4.2-8.7 minutes; clotting time (K): 1.2-3.2 minutes; alpha angle (α): 47.0-72.3 degree; maximum amplitude (MA): 49.1-70.5 mm for males, and R: 3.7-9.0 minutes; K: 1.0-3.2 minutes; α: 48.4-74.4 degree; MA: 46.8-72.4 mm for females. Also, the TEG parameters indicated a relatively more hypercoagulable profile in both female and elder groups.

CONCLUSIONS

This study established the reference values for kaolin-activated TEG in the target Chinese population, which might provide a reference for both clinical and laboratory studies.