The effect of hematocrit, fibrinogen concentration and temperature on the kinetics of clot formation of whole blood

Estimating Thrombus Elasticity by Shear Wave Elastography to Evaluate Ultrasound Thrombolysis for Thrombus With Different Stiffness

OBJECTIVE

There is uncertainty about deep vein thrombosis standard treatment as thrombus stiffness alters each case. Here, we investigated thrombus' stiffness of different compositions and ages using shear wave elastography (SWE). We then studied the effectiveness of ultrasound-thrombolysis on different thrombus compositions.

METHODS

Shear waves generated through mechanical shaker and traveled along thrombus of different hematocrit (HCT) levels, whereas 18-MHz ultrasound array used to detect wave propagation. Thrombus' stiffness was identified by the shear wave speed (SWS). In thrombolysis, a 3.2 MHz focused transducer was applied to different thrombus compositions using different powers. The thrombolysis rate was defined as the percentage of weight loss.

RESULTS

The estimated average SWS of 20%, 40%, and 60% HCT thrombus were 0.75 m/s, 0.44 m/s, and 0.32 m/s, respectively. For Thrombolysis, the percentage weight loss at 8 MPa Negative pressure for the same HCT groups were 23.1%, 35.29%, and 39.66% respectively.

CONCLUSION

SWS is inversely related to HCT level and positively related to thrombus age. High HCT thrombus had higher weight loss compared to low HCT. However, the difference between 20% and 40% HCT was more significant than between 40% and 60% HCT in both studies. Our results suggest that thrombus with higher SWS require more power to achieve the same thrombolysis rate as thrombus with lower SWS.

SIGNIFICANCE

Characterizing thrombus elastic property undergoing thrombolysis enables evaluation of ultrasound efficacy for fractionating thrombus and reveals the appropriate ultrasound parameters selection to achieve a certain thrombolysis rate in the case of a specific thrombus stiffness.

Evaluation of Haemostasis in Dogs Affected by Resectable Malignancy

Dogs with neoplasm are at risk of thrombosis, yet there is no information on the haemostatic alterations that may result from the surgeries performed to remove neoplastic masses. The aim of this study was to observe the characteristics of haemostasis in dogs undergoing surgery to remove a malignancy by means of rotational thromboelastometry and thrombin generation. Haemostasis was assessed immediately before surgery (T0), 24 h after surgery (T1), and two weeks after surgery (T2). Statistically significant differences were found between the thromboelastometric parameters at T0 vs. T1, with increases observed in MCF, the α angle, and G parameters in the ex-TEM and in-TEM profiles. In the thromboelastometric analysis performed after surgery differences were identified between T1 and T2, with a decrease observed in parameters such as CFT, MCF, the α angle, and G. Between T0 and T2, only a significant decrease in CT was detected in the fib-TEM profile. No differences were found in the comparison among the results obtained via thrombin generation. In dogs with resectable malignancies, the surgeries performed to remove cancer affected coagulation, causing a tendency towards hypercoagulability. The interference with coagulation was transient, and 2 weeks after surgery, the thromboelatometric results returned to those obtained before surgery (T0).

Space-time-regulated imaging analyzer for smart coagulation diagnosis

The development of intelligent blood coagulation diagnoses is awaited to meet the current need for large clinical time-sensitive caseloads due to its efficient and automated diagnoses. Herein, a method is reported and validated to realize it through artificial intelligence (AI)-assisted optical clotting biophysics (OCB) properties identification. The image differential calculation is used for precise acquisition of OCB properties with elimination of initial differences, and the strategy of space-time regulation allows on-demand space time OCB properties identification and enables diverse blood function diagnoses. The integrated applications of smartphones and cloud computing offer a user-friendly automated analysis for accurate and convenient diagnoses. The prospective assays of clinical cases (n = 41) show that the system realizes 97.6%, 95.1%, and 100% accuracy for coagulation factors, fibrinogen function, and comprehensive blood coagulation diagnoses, respectively. This method should enable more low-cost and convenient diagnoses and provide a path for potential diagnostic-markers finding.

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An ultraportable optofluidic analyzer empowers convenient coagulation diagnoses

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The system enables optical clotting biophysics (OCB) properties acquisition and process

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Coagulation function diagnoses uses intelligent OCB properties identification

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Space-time regulation of OCB properties endow it capability to diverse diagnoses

Sex-differential downregulation of methotrexate on plasma viscosity and whole blood viscosity in psoriasis

BACKGROUND: Psoriasis is associated with an increased risk for cardiovascular disease (CVD). Methotrexate (MTX) is often used as a first-line system therapy and there is a need to determine its effect on whole blood viscosity (WBV) and plasma viscosity (PV) in psoriasis. METHODS A prospective, single-center, interventional study with a total of 111 psoriatic patients who received MTX therapy from October 22, 2018, to December 28, 2019, and 111 age- and sex-matched healthy controls. Changes in WBV, PV, blood counts, liver and renal function were evaluated. RESULTS Psoriatic patients had significantly higher levels of WBV and relative viscosity (RV) at low shear rate (LSR), erythrocyte aggregation index (EAI), and PV than sex and age-matched healthy controls. PV was positively correlated with erythrocyte sedimentation rate (ESR), ESR was positively correlated with high sensitive C-reactive protein (hCRP). But only hCRP was positively associated with psoriasis area severity index (PASI) score. MTX significantly decreased the levels of PV, ESR, hCRP, and blood pressure (BP) in male patients, and the level of WBV in female patients. CONCLUSION: Sex-specific downregulation of MTX on WBV, PV, hCRP, and BP, indicating that the effect of MTX on the risk of cardiovascular disease was related with sex.

Thrombodynamics as a tool for monitoring hemostatic disorders in patients with chronic glomerulonephritis complicated by nephrotic syndrome

Nephrotic syndrome (NS) is associated with a high risk for venous and arterial thrombosis due to hypercoagulability. Integral tests designed to assess hemostasis can become an alternative for measuring hypercoagulability in patients with NS. STUDY OBJECTIVE: To assess hemostatic disorders in CGN patients complicated by NS using the thrombodynamics test. MATERIALS AND METHODS: The study included 60 adult patients with chronic glomerulonephritis (CGN), mean age 37 years, 31 (52%) women, and 29 (48%) men. Among all patients, 53 % of patients had NS, 47 % had no sign of NS. Hemostasis was assessed using the thrombodynamics test. The results were compared with biochemical parameters, which are usually associated with NS and renal dysfunction. RESULTS: According to the thrombodynamics test, CGN patients with NS demonstrated a tendency to hypercoagulability: increased rates of V (rate of clot growth), increased D (clot density), and increased CS (clot size) after 30 minutes. A positive correlation of these parameters with the serum albumin, creatinine levels, and glomerular filtration rate (GFR) indicates the influence of severe NS and renal dysfunction on the hemostasis activation in CGN patients with NS. CONCLUSION: According to the thrombodynamics test, CGN patients with NS demonstrate increased rates of clot formation, increased clot size after 30 minutes, and increased clot density due to secondary hemostasis activation. These changes positively correlate with the severity of hypoalbuminemia, hypercholesterolemia, and renal dysfunction in NS patients.

TEG®, Microclot and Platelet Mapping for Guiding Early Management of Severe COVID-19 Coagulopathy

An important component of severe COVID-19 disease is virus-induced endothelilitis. This leads to disruption of normal endothelial function, initiating a state of failing normal clotting physiology. Massively increased levels of von Willebrand Factor (VWF) lead to overwhelming platelet activation, as well as activation of the enzymatic (intrinsic) clotting pathway. In addition, there is an impaired fibrinolysis, caused by, amongst others, increased levels of alpha-(2) antiplasmin. The end result is hypercoagulation (proven by thromboelastography^® (TEG^®)) and reduced fibrinolysis, inevitably leading to a difficult-to-overcome hypercoagulated physiological state. Platelets in circulation also plays a significant role in clot formation, but they themselves may also drive hypercoagulation when they are overactivated due to the interactions of their receptors with the endothelium, immune cells or circulating inflammatory molecules. From the literature it is clear that the role of platelets in severely ill COVID-19 patients has been markedly underestimated or even ignored. We here highlight the value of early management of severe COVID-19 coagulopathy as guided by TEG^®, microclot and platelet mapping. We also argue that the failure of clinical trials, where the efficacy of prophylactic versus therapeutic clexane (low molecular weight heparin (LMWH)) were not always successful, which may be because the significant role of platelet activation was not taken into account during the planning of the trial. We conclude that, because of the overwhelming alteration of clotting, the outcome of any trial evaluating an any single anticoagulant, including thrombolytic, would be negative. Here we suggest the use of the degree of platelet dysfunction and presence of microclots in circulation, together with TEG^®, might be used as a guideline for disease severity. A multi-pronged approach, guided by TEG^® and platelet mapping, would be required to maintain normal clotting physiology in severe COVID-19 disease.

The effects of plasma viscosity in thromboembolic events among patients with essential thrombocytosis: A case-control study

INTRODUCTION

Essential thrombocythemia (ET) is an entity of classic Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs), characterized by thrombocytosis with megakaryocytic hyperplasia where in the thrombocytes are increased with abnormal function.Thrombotic events are seen frequently and represent the main cause of morbidity and mortalityin patients with MPNs, mainly polycythemia vera and ET. This study has aimed to research the effects of clonally increased thrombocytes on plasma viscosity (PV) levels among patients with ET and the relationship between PV and thromboembolism history, according to the hypotheses about the effects of PV in thromboembolic events among patients with ET.

METHODS

A total of 55 patients were enrolled in the study group, 18 of who had been newly diagnosed with ET according to 2016 World Health Organization criteria and had not previously been treated. 37 of them had already been diagnosed with ET and had been treated. There were 47 healthy volunteers in the control group. 5 cc blood samples were taken from the patients into tubes including an anticoagulant to measure their PV levels.

RESULTS

PV of the control group was found to be lower than in the study group and both each patient groups (p <  0.05). No relationship was found between the patient groups in terms of PV (p = 0.404). The mean PV levels of the 16 patients with a history of thromboembolism and the 39 patients with no such history were 2.42±0.17 cP and 2.33±0.20 cP, respectively. The mean PV levels were found to be similar according to their history of thromboembolism in all patient groups and in treated patients (p = 0.572 vs p = 0.991).

CONCLUSION

We have found that PV levels were increased in clonally increased thrombocytes in patients with ET when compared with the control group. This is the first study in this field according to our knowledge.

Impact of cardiovascular burden on coagulation pathway in apparently healthy women planning oocyte donation

BACKGROUND

Hormonal fertility treatments are associated with increased coagulation factors inducing procoagulant milieu and possibly thrombotic risk.

OBJECTIVE

To assess coagulation by ROTEM and coagulation tests in apparently healthy infertile women before oocyte donation procedure.

METHODS

We enrolled 51 women (Assisted Reproductive Technology Centre, Florence). ROTEM and coagulation parameters were assessed before the start of infertility treatment.

RESULTS

We divided women in 3 groups according to the number of cardiovascular risk factors: Group A (n = 10), Group B (n = 16), and Group C (n = 25). By considering ROTEM Extem test, a significantly increased of MCF, TPI, and G were observed in groups B (p = 0.005, p = 0.03, and p = 0.007) and C (p = 0.01, p = 0.05, and p = 0.005) in comparison to group A. As regards ROTEM Intem test, the TPI and G values were significantly higher in groups B and C in comparison to group A (p < 0.01). MCF by Fibtem test significantly increased in groups B and C than in group A (p = 0.004 and p = 0.002, respectively). FVIII, vWF:Ag and D-dimer values significantly increase according to the presence of≥2 risk factors.

CONCLUSIONS

Data from coagulative assessment permit to sensitively identify women with potentially procoagulable state, which represents a risk factor of thromboembolic event during hormone treatment.

Phase separation during blood spreading

Blood pools can spread on several types of substrates depending on the surrounding environment and conditions. Understanding the influence of these parameters on the spreading of blood pools can provide crime scene investigators with useful information. The focus of the present study is on phase separation, that is, when the serum spreads outside the main blood pool. For this purpose, blood pools with constant initial masses on wooden floors that were either varnished or not were created at ambient temperatures of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$21~^{\circ }\hbox {C}$$\end{document}21∘C, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$29~^{\circ }\hbox {C}$$\end{document}29∘C, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$37~^{\circ }\hbox {C}$$\end{document}37∘C with a relative humidity varying from 20 to 90%. The range \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$21~^{\circ }\hbox {C}$$\end{document}21∘C to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$37~^{\circ }\hbox {C}$$\end{document}37∘C covers almost all worldwide indoor cases. The same whole blood from the same donor was used for all experiments. As a result, an increase in relative humidity was found to result in an increase in the final pool area. In addition, at the three different experimental temperatures, the serum spread outside the main pool at relative humidity levels above 50%. This phase separation is more significant on varnished substrates, and does not lead to any changes in the drying morphology. This phenomenon is explained by the competition between coagulation and evaporation.

Is major burn injury associated with coagulopathy? The value of thrombelastometry in the detection of coagulopathy in major burn injury: A prospective observational study

BACKGRUND

The coagulation status of burn patients is generally impaired and is a major factor of the deteriorating burn patients' overall situation. In trauma and other patient groups, the differential diagnosis of coagulation impairment has been largely improved by the use of rotational thromboelastometry (ROTEM®). The aim of this prospective observational study was the differentiated observation of coagulopathy in severely burned patients using standard parameters and ROTEM® thrombelastometry during the relevant stages of burn disease.

PATIENTS AND METHODS

Twelve patients that sustained at least 20% third degree burns of total body surface area (TBSA) were included in the study. Standard and ROTEM® coagulation analyses were performed on admission and then twice daily during the first 14 days following burn trauma.

RESULTS

Although the initial assessment of DIC was similar for both standard labs and ROTEM® measurements, more patients were detected to be in a state of worsening coagulation status for a longer time in ROTEM® than in standard measurements. In addition, one patient was rated in to be in decompensated DIC for 3 days according to ROTEM® measurements, while no patient was rated to be in a decompensated DIC based on standard parameters.

CONCLUSION

This study points towards a more complex picture and higher occurrence of DIC in burn patients when thrombelastometric measurements like ROTEM® are taken into account in addition to standard coagulation parameters.

Blood Clot Phenotyping by Rheometry: Platelets and Fibrinogen Chemistry Affect Stress-Softening and -Stiffening at Large Oscillation Amplitude

(1) Background: Together with treatment protocols, viscoelastic tests are widely used for patient care. Measuring at broader ranges of deformation than currently done will add information on a clot’s mechanical phenotype because fibrin networks follow different stretching regimes, and blood flow compels clots into a dynamic non-linear response. (2) Methods: To characterize the influence of platelets on the network level, a stress amplitude sweep test (LAOStress) was applied to clots from native plasma with five platelet concentrations. Five species were used to validate the protocol (human, cow, pig, rat, horse). By Lissajous plots the oscillation cycle for each stress level was analyzed. (3) Results: Cyclic stress loading generates a characteristic strain response that scales with the platelet quantity at low stress, and that is independent from the platelet count at high shear stress. This general behavior is valid in the animal models except cow. Here, the specific fibrinogen chemistry induces a stiffer network and a variant high stress response. (4) Conclusions: The protocol provides several thresholds to connect the softening and stiffening behavior of clots with the applied shear stress. This points to the reversible part of deformation, and thus opens a new route to describe a blood clot’s phenotype.