Clot Growth Rate Research Articles

Pro‑coagulant Considerations in Patients with Arterial Hypertension and Multifocal Atherosclerosis

The aim of the work to determine the features of hemostasis and blood rheology in patients with arterial hypertension (HTN) and multifocal atherosclerosis (MFA).Materials and methods. The study enrolled male and female patients aged from 40 to 70 years, including 59 patients with controlled stage I–II hypertension and multifocal vascular lesions (Group 1) and 42 patients with controlled stage III hypertension, who have suffered an ischemic stroke and have multifocal vascular lesions (Group 2). A test using the Thrombodynamics analyser system T-2 (GemaKor, LLC, Moscow, Russia) was performed to detect the impairment of hemostasis.Results. Patients with HTN and MFA have an impaired coagulation hemostasis system (an increase in the initial and stationary clot growth rate and the size of the clot, as well as the presence of spontaneous clots), which leads to a high residual risk of cerebral complications, despite BP lowering to target figures and control of lipid profile.Discussion. Elevated blood pressure in patients with MFA leads to endothelial dysfunction, which is accompanied by activation of coagulation and fibrinolysis pathways. These changes lead to a violation of microcirculatory hemostasis in the brain, the development and progression of cerebral ischemia, and subsequently the occurrence of stroke, both the first and repeated.Conclusion. An important result of this study is the first registered change in the coagulation link of hemostasis in patients with HTN and MFA aged from 40 to 70 years, which can be considered an additional criterion for stroke prediction.

Trauma patients have reduced ex vivo flow-dependent platelet hemostatic capacity in a microfluidic model of vessel injury.

Trauma is the leading cause of death in individuals up to 45 years of age. Alterations in platelet function are a critical component of trauma-induced coagulopathy (TIC), yet these changes and the potential resulting dysfunction is incompletely understood. The lack of clinical assays available to explore platelet function in this patient population has hindered detailed understanding of the role of platelets in TIC. The objective of this study was to assess trauma patient ex vivo flow-dependent platelet hemostatic capacity in a microfluidic model. We hypothesized that trauma patients would have flow-regime dependent alterations in platelet function. Blood was collected from trauma patients with level I activations (N = 34) within 60 min of hospital arrival, as well as healthy volunteer controls (N = 10). Samples were perfused through a microfluidic model of injury at venous and arterial shear rates, and a subset of experiments were performed after incubation with fluorescent anti-CD41 to quantify platelets. Complete blood counts were performed as well as plasma-based assays to quantify coagulation times, fibrinogen, and von Willebrand factor (VWF). Exploratory correlation analyses were employed to identify relationships with microfluidic hemostatic parameters. Trauma patients had increased microfluidic bleeding times compared to healthy controls. While trauma patient samples were able to deposit a substantial amount of clot in the model injury site, the platelet contribution to microfluidic hemostasis was attenuated. Trauma patients had largely normal hematology and plasma-based coagulation times, yet had elevated D-Dimer and VWF. Venous microfluidic bleeding time negatively correlated with VWF, D-Dimer, and mean platelet volume (MPV), while arterial microfluidic bleeding time positively correlated with oxygenation. Arterial clot growth rate negatively correlated with red cell count, and positively with mean corpuscular volume (MCV). We observed changes in clot composition in trauma patient samples reflected by significantly diminished platelet contribution, which resulted in reduced hemostatic function in a microfluidic model of vessel injury. We observed a reduction in platelet clot contribution under both venous and arterial flow ex vivo in trauma patient samples. While our population was heterogenous and had relatively mild injury severity, microfluidic hemostatic parameters correlated with different patient-specific data depending on the flow setting, indicating potentially differential mechanistic pathways contributing to platelet hemostatic capacity in the context of TIC. These data were generated with the goal of identifying key features of platelet dysfunction in bleeding trauma patients under conditions of flow and to determine if these features correlate with clinically available metrics, thus providing preliminary surrogate markers of physiological platelet dysfunction to be further studied across larger cohorts. Future studies will continue to explore those relationships and further define mechanisms of TIC and their relationship with patient outcomes.

Hemostasis parameters in patients with arterial hypertension, multifocal atherosclerosis and risk factors

Aim. To determine the features of hemostasis system disorders and the possibility of their correction in patients with arterial hypertension (AH) and multifocal atherosclerotic lesions (MFA) with risk factors indicated.Materials and methods. The study included 135 patients (mean age 53.7 ± 7.76 years), including 80 patients with controlled AH stage and II (group 1) and 55 patients with controlled AH stage III who had ischemic stroke (group 2). Among all patients studied, 33 patients (24.4 %) were smokers. All 135 patients received comparable antihypertensive, antiplatelettherapy (acetylsalicylic acid at a dose of 100 mg/day), had MFA and target lipid spectrum values.Results. Procoagulant shifts are noted already in patients with AH stage I and II, especially in the presence of smoking. Such indices of global thrombodynamics test as initial clot growth rate, average clot growth rate, clot size significantly exceed the reference values and indicate high prothrombogenic potential in patient with AH and MFA. Prescription of dual antiplatelet therapy allows normalization of identified disorders. Presence of risk factors (smoking) aggravates existing hemostasis disorders in patients with AH and MFA.Conclusion. Smoking cessation, optimization of risk factors and complex antihypertensive, hypolipidemic and antithrombotic therapy are the basis of treatment of patients with AH and MFA and can be considered as priority measures to reduce morbidity and mortality in this patient population.

Global coagulation assays detect an early prothrombotic state in children with acute lymphoblastic leukemia

BackgroundPediatric patients with acute lymphoblastic leukemia (ALL) are at highest risk of venous thromboembolism during the induction therapy (IT). These events are not predictable by conventional coagulation assays. ObjectivesTo investigate the utility of global coagulation assays (GCAs) for assessing the hemostatic state in children with ALL during IT. MethodsWe included children with ALL (n = 15) and healthy controls (n = 15). Analyses were performed at different time points during IT of the AIEOP-BFM protocols. In addition to prothrombotic biomarkers, natural anticoagulant proteins, and in vivo thrombin generation (TG) markers, ex vivo TG was measured using the gold standard calibrated automated thrombogram method, automated ST Genesia, and thrombodynamics analyzer (TD). The latter also provided measurement of fibrin clot formation. ResultsDifferent from conventional coagulation assays and in vivo TG markers, ex vivo GCAs detected increasing prothrombotic changes during IT. Particularly, TG measured with TD as expressed by endogenous thrombin potential was already significantly elevated at days 8 to 12 (P < .01) and continued to increase during IT compared with prior to beginning treatment, indicating a very early shift toward a procoagulant state. A similar pattern was observed for the rate of fibrin clot formation (stationary rate of clot growth: P < .01 at days 8-12). Remarkably, in patients developing thrombotic complications (n = 5), both GCAs, ST Genesia and TD, showed a significantly higher endogenous thrombin potential very early (already at days 8-12, P < .05), well before clinical manifestation. ConclusionGCAs capture prothrombotic changes early during IT in ALL pediatric patients. If confirmed, this approach will allow tailoring thromboprophylaxis in children with ALL at highest risk for venous thromboembolism.

Comparison of thrombodynamic tests with determination of anti-Xa activity in evaluation of the efficacy of anticoagulant therapy in patients suffering deep vein thrombosis of the lower extremities

Deep vein thrombosis of the lower extremities remains an important medical and social problem in practical medicine. Currently, a weight-dependent low-molecular-weight heparin dosing approach is used to treat deep vein thrombosis of the lower extremities in wounded patients without regard to the state of the hemostasis system. This observational study included 30 patients with deep vein thrombosis of the lower extremities who were hospitalized for examination and treatment at the Kirov Military Medical Academy. During treatment with enoxaparin sodium at therapeutic doses, depending on body weight, the parameters of the thrombodynamics test were assessed in all patients, and antiXa activity was determined at the peak of the drug (after 3–4 h) and at the end (before the next injection) of its action. A strong inverse correlation was established between the growth rate indicator of the thrombodynamics test clot and antiXa activity at the peak (–0.777; p 0.05) and at the end (–0.715; p 0.05) of the action of sodium enoxaparin. The standard dose of anticoagulant drug, depending on body weight, revealed that 30% of patients were in the hypercoagulation zone, not reaching the target values of the thrombodynamic clot growth rate and anti-Xa activity. The thrombodynamics test results identified the growth rate of the test clot with antiXa activity, which allows both methods to be considered comparable for laboratory monitoring low-molecular-weight heparin therapy in wounded individuals. The insufficient anticoagulant effect in one-third of the injured individuals that received the standard and therapeutic doses of low-molecular-weight heparins requires the development of a personalized approach to titration of low-molecular-weight heparins, which may be based not on the concentration of the drug per body weight but on the achieved anticoagulant effect that optimizes the treatment outcomes and patient prognosis. Accordingly, further research is required.

GWAS-significant loci and severe COVID-19: analysis of associations, link with thromboinflammation syndrome, gene-gene, and gene-environmental interactions.

The aim of this study was to replicate associations of GWAS-significant loci with severe COVID-19 in the population of Central Russia, to investigate associations of the SNPs with thromboinflammation parameters, to analyze gene-gene and gene-environmental interactions. DNA samples from 798 unrelated Caucasian subjects from Central Russia (199 hospitalized COVID-19 patients and 599 controls with a mild or asymptomatic course of COVID-19) were genotyped using probe-based polymerase chain reaction for 10 GWAS-significant SNPs: rs143334143 CCHCR1, rs111837807 CCHCR1, rs17078346 SLC6A20-LLZTFL1, rs17713054 SLC6A20-LLZTFL1, rs7949972 ELF5, rs61882275 ELF5, rs12585036 ATP11A, rs67579710 THBS3, THBS3-AS1, rs12610495 DPP9, rs9636867 IFNAR2. SNP rs17713054 SLC6A20-LZTFL1 was associated with increased risk of severe COVID-19 in the entire group (risk allele A, OR = 1.78, 95% CI = 1.22-2.6, p = 0.003), obese individuals (OR = 2.31, 95% CI = 1.52-3.5, p = 0.0002, (p bonf = 0.0004)), patients with low fruit and vegetable intake (OR = 1.72, 95% CI = 1.15-2.58, p = 0.01, (p bonf = 0.02)), low physical activity (OR = 1.93, 95% CI = 1.26-2.94, p = 0.0035, (p bonf = 0.007)), and nonsmokers (OR = 1.65, 95% CI = 1.11-2.46, p = 0.02). This SNP correlated with increased BMI (p = 0.006) and worsened thrombodynamic parameters (maximum optical density of the formed clot, D (p = 0.02), delayed appearance of spontaneous clots, Tsp (p = 0.02), clot size 30min after coagulation activation, CS (p = 0.036)). SNP rs17078346 SLC6A20-LZTFL1 was linked with increased BMI (p = 0.01) and severe COVID-19 in obese individuals (risk allele C, OR = 1.72, 95% CI = 1.15-2.58, p = 0.01, (p bonf = 0.02)). SNP rs12610495 DPP9 was associated with increased BMI (p = 0.01), severe COVID-19 in obese patients (risk allele G, OR = 1.48, 95% CI = 1.09-2.01, p = 0.01, (p bonf = 0.02)), and worsened thrombodynamic parameters (time to the start of clot growth, Tlag (p = 0.01)). For rs7949972 ELF5, a protective effect against severe COVID-19 was observed in non-obese patients (effect allele T, OR = 0.67, 95% CI = 0.47-0.95, p = 0.02, (p bonf = 0.04)), improving thrombodynamic parameters (CS (p = 0.02), stationary spatial clot growth rates, Vst (p = 0.02)). Finally, rs12585036 ATP11A exhibited a protective effect against severe COVID-19 in males (protective allele A, OR = 0.51, 95% CI = 0.32-0.83, p = 0.004). SNPs rs67579710 THBS3, THBS3-AS1, rs17713054 SLC6A20-LZTFL1, rs7949972 ELF5, rs9636867 IFNAR2-were involved in two or more of the most significant G×G interactions (p perm ≤ 0.01). The pairwise combination rs67579710 THBS3, THBS3-AS1 × rs17713054 SLC6A20-LZTFL1 was a priority in determining susceptibility to severe COVID-19 (it was included in four of the top five most significant SNP-SNP interaction models). Overall, this study represents a comprehensive molecular-genetic and bioinformatics analysis of the involvement of GWAS-significant loci in the molecular mechanisms of severe COVID-19, gene-gene and gene-environmental interactions, and provides evidence of their relationship with thromboinflammation parameters in patients hospitalized in intensive care units.

Thrombodynamics and Quantitative phase imaging of platelets in the assessment of hemostasis in pregnant women with protein C / protein S deficiency

Relevance. A hypercoagulable state caused by hereditary or acquired deficiency of antithrombotic factors can contribute to disruption of the uteroplacental circulation with the development of serious pregnancy complications, which requires effective monitoring of hemostasis during the use of pathogenetic anticoagulant therapy.The purpose of the study is to improve methods for diagnosing and monitoring hemostatic disorders in pregnant women with thrombophilia (protein C/protein S deficiency) and complicated pregnancy based on the use of an integral thrombodynamic test and quantitative phase imaging of platelets.Material and methods. 45 pregnant women were examined in the first and second trimester: 20 women with normal pregnancy (comparison group) and 25 (main group) with thrombophilia (protein S/protein C deficiency). 16 pregnant women (subgroup 1A) received a full course of preconception preparation with the prescription of LMWH, 9 pregnant women (subgroup 1B) did not complete the course in full for various reasons. To study hemostasis, along with routine methods (determination of APTT, TT, PT, Fibrinogen, INR and D-dimer), an integral assessment of coagulation using the Thrombodynamics method and quantitative phase imaging (QPI) of platelets in real time were performed.Results. It was found that routine methods are not sufficiently informative; statistically significant changes against the background of thrombophilia and during treatment with LMWH were noted only based on the results of assessing the level of fibrinogen and D-dimer. In the complex of thrombodynamics indicators, the most sensitive parameters were the steady-state clot growth rate (Vst), clot size at 30 minutes of the study (CS) and clot density (D). The QPI method revealed features of the morphological structure of platelets with a predominance in pregnant women with protein S/protein C deficiency of the activated cell population with an increase in the median values of diameter and perimeter by 14 and 20 %, respectively (p &lt; 0.05). The effectiveness of LMWH therapy was assessed by normalization of the analyzed parameters.Conclusion. Timely and adequate correction of hemostasis disorders, carried out while monitoring coagulation and platelet parameters, taking into account all clinical data, can significantly reduce the risk of complications for the mother and fetus.

Platelets provide robustness of spatial blood coagulation to the variation of initial conditions

Activated platelets provide phospholipid surface and secrete coagulation factors, enhancing blood clotting. We investigated the role of platelets in the regulation of blood coagulation spatial dynamics. We activated blood clotting with tissue factor-bearing (TF) surface in platelet-rich plasma (PRP) or platelet-free plasma (PFP). When blood coagulation was initiated by high TF density, clot growth rate (V) in PRP (2 × 105/μL platelets) was only 15 % greater than in PFP. Spatial distribution of thrombin in PRP had a peak-like shape in the area of the fibrin clot edge, while in PFP thrombin was distributed in the shape of descending plateau. Platelet inhibition with prostaglandin E1 or cytochalasin D made spatial thrombin distribution look like in the case of PFP. Inhibition of blood coagulation by natural endogenous inhibitor heparin was diminished in PRP, while the effect of the exogenous or artificial inhibitors (rivaroxaban, nitrophorin, hirudin) remained undisturbed in the presence of platelets. Ten times decrease of the TF surface density greatly depressed blood coagulation in PFP. In PRP only clotting initiation phase was, while the propagation phase remained intact. Coagulation factor deficiency greatly reduced amount of thrombin and decreased V in PFP rather than in PPR. Thus, platelets were redundant for clotting in normal plasma under physiological conditions but provided robustness of the coagulation system to the changes in initial conditions.

СРАВНИТЕЛЬНЫЙ МОНИТОРИНГ АНТИКОАГУЛЯНТНОЙ ТЕРАПИИ У РАНЕНЫХ С ТРОМБОЗАМИ ГЛУБОКИХ ВЕН НИЖНИХ КОНЕЧНОСТЕЙ

Introduction. Deep vein thrombosis of the lower extremities (DVT) currently remains one of the most important problems affecting not only vascular surgeons, but also doctors of other specialties. Target. Carry out a comparative monitoring of methods for monitoring the effectiveness of anticoagulant therapy in the wounded using the Thrombodynamics test and determining anti-Xa activity. Materials and methods. The study included 30 wounded individuals with established DVT, hospitalized for examination and treatment at the Military Medical Academy. CM. Kirov. Against the background of treatment with enoxaparin sodium (hereinafter referred to as enoxaparin) at therapeutic doses, depending on body weight, all patients were assessed the parameters of the "Thrombodynamics" (TD) test and the determination of anti-Xa activity at the peak of the drug's action (after 3-4 hours), and on outcome (before the next injection) of the drug. Statistical data processing was carried out using the Statistica 10.0 application package. Results and discussion. A strong inverse correlation was established between the clot growth rate (V) of the TD test and the determination of anti-Xa activity at the peak (-0.777; p&lt;0.05) and at the end (-0.715; p&lt;0.05) of anticoagulant therapy. With the standard prescription of doses of anticoagulant therapy depending on body weight, it was found that 30% of patients did not reach the target values of the V TD test and anti-Xa activity and were in the hypercoagulable zone. Conclusion. The indicator of clot growth rate of the "Thrombodynamics" test correlates with the level of anti-Xa activity and can be used as another tool for laboratory monitoring of ongoing therapy with low molecular weight heparins (LMWH) in the wounded. The standard use of LMWH in therapeutic doses by body weight in the wounded does not always lead to the achievement of target coagulation parameters, which requires the development of a personalized approach to LMWH titration, which can be based on the indicators of TD tests and anti-Xa activity.

Targeted Blood Plasma Proteomics and Hemostasis Assessment of Post COVID-19 Patients with Acute Myocardial Infarction

The molecular mechanisms underlying cardiovascular complications after the SARS-CoV-2 infection remain unknown. The goal of our study was to analyze the features of blood coagulation, platelet aggregation, and plasma proteomics in COVID-19 convalescents with AMI. The study included 66 AMI patients and 58 healthy volunteers. The groups were divided according to the anti-N IgG levels (AMI post-COVID (n = 44), AMI control (n = 22), control post-COVID (n = 31), and control (n = 27)). All participants underwent rotational thromboelastometry, thrombodynamics, impedance aggregometry, and blood plasma proteomics analysis. Both AMI groups of patients demonstrated higher values of clot growth rates, thrombus size and density, as well as the elevated levels of components of the complement system, proteins modifying the state of endothelium, acute-phase and procoagulant proteins. In comparison with AMI control, AMI post-COVID patients demonstrated decreased levels of proteins connected to inflammation and hemostasis (lipopolysaccharide-binding protein, C4b-binding protein alpha-chain, plasma protease C1 inhibitor, fibrinogen beta-chain, vitamin K-dependent protein S), and altered correlations between inflammation and fibrinolysis. A new finding is that AMI post-COVID patients opposite the AMI control group, are characterized by a less noticeable growth of acute-phase proteins and hemostatic markers that could be explained by prolonged immune system alteration after COVID-19.

Reactogenicity of various COVID-19 vaccination regimens

During the spread of an increasing number of new variants of Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2), it is extremely important not only to assess the immunogenicity and efficacy, butalso the safety of various combinations of vaccines. Excessive immune response and associated signs and symptoms may occur with varying frequency as expected from the use of vaccines.Aim. To compare the reactogenicity of various (heterologous and homologous) vaccination regimens in a prospective observational study.Material and methods. In individuals aged ≥18 years, in the absence of contraindications to vaccination, two types of vaccines were used at primary vaccination and revaccination: Gam-COVID-Vac and CoviVac: group I (n=97) — Gam-COVID-Vac at each stage of primary and booster vaccination ; group II (n=7) — Gam-COVID-Vck at each stage of primary vaccination, CoviVac at each stage of revaccination; group III (n=42) — CoviVac at each stage of primary vaccination, Gam-COVID-Vac at each stage of revaccination; group IV (n=38) — CoviVac at each stage of primary and secondary vaccination. In all participants, the dynamics of IgG to SARS-CoV-2 spike glycoprotein receptor-binding domain and T-cell immunity to SARS-CoV-2 were determined over time. To control the plasma hemostasis, the method of dynamic thrombophotometry was used. Local and systemic adverse events were assessed.Results. The number of vaccinated individuals with a rise in body temperature above 370 C after the 1st stage of revaccination was significantly (p&lt;0,05) more in group I (37,5%) and group II (57,1%) compared with vaccinated persons of IV group. At the same time, after the 2nd stage of revaccination, in general, a smaller percentage of vaccinated persons with hyperthermia was noted. In group I, a higher percentage of persons (22,9%) complaining of the appearance of weakness after stage I of revaccination was noted compared to vaccinated persons of group IV — 5,2%. An increase in the fibrin clot growth rate was noted in group III at the stage of revaccination.Conclusion. The use of various revaccination schemes (homologous and heterologous) was not associated with the development of serious adverse events. The resulting local and systemic reactions were shortlived and did not require hospitalization. More pronounced systemic reactions were noted in the form of a short-term fever and weakness when using the Gam-COVID-Vac. No cases of arterial or venous thrombosis were registered during the follow-up period.

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

To assess hemostatic disorders in CGN patients complicated by NS using the thrombodynamics test. 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. 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. 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.

Thrombodynamics Test in Assessing the Risk of Thrombus Formation in Patients with Atrial Fibrillation Taking Direct Oral Anticoagulants

Aim. To evaluate thrombus characteristics in patients with atrial fibrillation (AF) taking different direct oral anticoagulants (DOACs) using Thrombodynamics test.Materials and methods. Thrombodynamics test was performed in 100 patients with paroxysmal and permanent forms of AF taking different DOACs, dose choice was done in accordance with the instructions for drugs use. For analysis samples of fresh citrated platelet-free plasma were taken just before regular DOACs dose intake (trough concentration). Statistical data processing was carried out using R software packages.Results. All patients had no history of thrombosis or bleeding before inclusion in this study. All parameters of Thrombodynamics test taken at residual concentration of DOACs were in general within reference values, that is in the area of normal coagulation: spatial clot growth rate (V) – 26.56 (25.0; 29.2) μm/min, the time to the start of clot growth (Tlag) – 1.05 (0.85; 1.27) min, initial spatial clot growth rate (Vi) – 44.3±7.7 μm/min, stationary spatial clot growth rate (Vst) – 26.5 (24.9; 28.4) μm/min, clot size (CS) – 999.7 (912.9; 1084.7) μm, clot density (D) – 22883.1±3199.9 arb. units. D was appeared to be higher in women [22947.7 (21477.5; 22947.7) vs men [22124.8 (19722.8; 22124.8), p=0.035] and Tlag was significantly higher in patients with chronic heart failure [1.2 (1.0; 1.2) vs 1.0 (0.8; 1.0), p=0.008]. A correlation was found between level of creatinine and Tlag parameter, glomerular filtration rate (GFR) and clot density. With an increase in the level of creatinine in the blood and a decrease in GFR, respectively, there was an increase in Tlag parameter (p-value 0.038); with an increase in GFR, clot density decrease (p-value 0.005).Conclusion. All parameters of Thrombodynamics test on residual concentration of DOACs were within reference values that indicated optimal anticoagulant effect of all DOACs. The obtained data of normal coagulation at the residual concentration of the anticoagulant are consistent with the previously obtained data on the safety and effectiveness of DOACs using other methods. Further studies with clinical end points are needed to assess the clinical value of this method.

Peculiarities of hemostasis in patients with COVID-19

Analysis of the dynamics of different stages of clot formation and its lysis in patients with different COVID-19 severity. We prospectively included 58 patients with COVID-19 (39 patients with moderate disease severity and 18 patients with severe disease) and 47 healthy volunteers as a control group. All participants underwent the assessment of flow-mediated dilation (FMD) of brachial artery, impedance aggregometry, rotational thromboelastometry and thrombodynamics. Von Willebrand factor antigen (vWF:Ag) quantification was also performed in patients with COVID-19. Measurements were repeated on the 3rd and 9th day of hospitalization. Compared to the control group, patients with COVID-19 showed reduced values of platelet aggregation and greater values of the clot growth rate, as well as its size and density. On the first day of hospitalization, we found no differences in the activity of plasma hemostasis and endogenous fibrinolysis between subgroups of patients. With the progression of the disease, the growth rate and size of the clot were higher in the severe subgroup, even despite higher doses of anticoagulants in this subgroup. An increase in platelet aggregation was noted during the progression of the disease, especially in the severe subgroup. There were no differences in the results of the FMD test by subgroups of patients. The vWF:Ag level was significantly higher in the severe subgroup. Thus, plasma hemostasis followed by secondary platelet activation correlates with the severity of COVID-19. Patients with moderate to severe coronavirus infection have predominantly local rather than generalized endothelial dysfunction.

​Circulating Cytokines in Myocardial Infarction Are Associated With Coronary Blood Flow.

BackgroundThe level of systemic inflammation correlates with the severity of the clinical course of acute myocardial infarction (AMI). It has been shown that circulating cytokines and endothelial dysfunction play an important role in the process of clot formation. The aim of our study was to assess the concentration of various circulating cytokines, endothelial function and blood clotting in AMI patients depending on the blood flow through the infarction-related artery (IRA).MethodsWe included 75 patients with AMI. 58 presented with ST-elevation myocardial infarction (STEMI) and 17 had non-ST-elevation myocardial infarction (non-STEMI). A flow-mediated dilation test (FMD test), thrombodynamics and rotational thromboelastometry as well as assessment of 14 serum cytokines using xMAP technology were performed.FindingsNon-STEMI-patients were characterized by higher levels of MDC, MIP-1β, TNF-α. Moreover, we observed that patients with impaired blood flow through the IRA (TIMI flow 0-1) had higher average and initial clot growth rates, earlier onset of spontaneous clots, C-reactive protein (CRP) and IL-10 compared to patients with preserved blood flow through the IRA (TIMI flow 2-3). Patients with TIMI 2-3 blood flow had higher level of IP-10. IL-10 correlated with CRP and pro-inflammatory cytokines levels, initial clot growth rate and clot lysis time in TIMI 0-1 patients. All these differences were statistically significant.InterpretationWe demonstrated that concentrations of the inflammatory cytokines correlate not only with the form of myocardial infarction (STEMI or non-STEMI), but also with the blood flow through the infarct-related artery. Inflammatory response, functional state of endothelium, and clot formation are closely linked with each other. A combination of these parameters affects the patency of the infarct-related artery.

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.

Correction of Anticoagulant Therapy in Patients with Severe COVID-19 Virus Infection Using a Thrombodynamics Coagulation Assay.

The average frequency of thrombosis in patients with COVID-19 is still high despite low molecular weight heparin (LMWH) prophylactic. Global hemostasis assays, particularly thrombodynamics (TD), known to be sensitive to both hypercoagulation and heparin effects, could potentially be useful for individual management of anticoagulant therapy. A total of 74 patients with lung involvement >50% were randomized into two groups: Group A (44 patients) received weight-based dosing of LMWH, and Group B (30 patients) received the first LMWH dose by a weight-based dosing protocol and then received an adjusted dose based on TD daily results. The endpoints of the study were thrombosis and bleeding as well as discharge or death of the patient. The incidence of thrombosis was 3 times lower in Group B under TD control compared to Group A without TD control: 7% versus 23 respectively (p = .05). The relative risk of thrombosis if the average clot growth rate V in TD exceeded the threshold value of 25 μm/min was 14.3 (p = .0005, 95% confidence interval 3.2-63.7). There were no clinically significant bleeding episodes in Group B while there were 7% in unregulated Group A. Mortality in Group B under TD control was lower than that in Group A without control: 27% versus 36%, respectively (p = .13). The dosing LMWH under thrombodynamics control in severe patients with COVID-19 allows for a significant reduction in thrombotic complications. Long-term hypercoagulation revealed by thrombodynamics (3 and more days) is a strong predictor of thrombosis (AUC = 0.83).

Hypercoagulation detected by routine and global laboratory hemostasis assays in patients with infective endocarditis

BackgroundCoagulation system is heavily involved into the process of infective endocarditis (IE) vegetation formation and can facilitate further embolization. In this study we aimed to assess the coagulation and platelet state in IE implementing a wide range of standard and global laboratory assays. We also aim to determine whether prothrombotic genetic polymorphisms play any role in embolization and mortality in IE patients.Methods37 patients with IE were enrolled into the study. Coagulation was assessed using standard coagulation assays (activated partial thromboplastin time (APTT), prothrombin, fibrinogen, D-dimer concentrations) and integral assays (thromboelastography (TEG) and thrombodynamics (TD)). Platelet functional activity was estimated by flow cytometry. Single nuclear polymorphisms of coagulation system genes were studied.ResultsFibrinogen concentration and fibrinogen-dependent parameters of TEG and TD were increased in patients indicating systemic inflammation. In majority of patients clot growth rate in thrombodynamics was significantly shifted towards hypercoagulation in consistency with D-dimers elevation. However, in some patients prothrombin, thromboelastography and thrombodynamics were shifted towards hypocoagulation. Resting platelets were characterized by glycoprotein IIb-IIIa activation and degranulation. In patients with fatal IE, we observed a significant decrease in fibrinogen and thrombodynamics. In patients with embolism, we observed a significant decrease in the TEG R parameter. No association of embolism or mortality with genetic polymorphisms was found in our cohort.ConclusionsOur findings suggest that coagulation in patients with infective endocarditis is characterized by general hypercoagulability and platelet pre-activation. Some patients, however, have hypocoagulant coagulation profile, which presumably can indicate progressing of hypercoagulation into consumption coagulopathy.

Is endothelial dysfunction a driving force of COVID-19 induced coagulopathy?

Background/IntroductionThere are numerous reports regarding the direct endothelial damage by the SARS-CoV-2 that can lead to activation of both plasma hemostasis and platelet aggregation. However, the mechanism of interaction between endothelium and haemostasis in COVID-19 remains unclear.PurposeThe aim of our study was to assess the relationship between each link of clot formation process (endothelial function, plasma coagulation, platelet aggregation) with the severity of the disease.Methods58 COVID-19 patients were included in our study. Patients were divided into moderate (n=39) and severe (n=18) subgroups. All patients underwent a flow-mediated dilation (FMD) test, impedance aggregation, rotational thromboelastometry, thrombodynamics and von Willebrand factor antigen (vWF: Ag) quantification. All measurements were repeated on days 3 (point 2) and 9 (point 3) of hospitalization.ResultsCOVID-19 patients demonstrated the enhanced plasma coagulation (clotting time, s 613,0 [480; 820], clot growth rate, μm/min 32,75 [29,3; 38,7]). At point 1 no significant difference in parameters of plasma coagulation between patients' subgroups was noted. At point 2 a significant decrease in the size (CS, μm 1278.0 [1216.5; 1356.5] vs 965.0 [659.8; 1098.0], p<0,01) and clot growth rate (μm/min 32,4 [29,2; 35,0] vs 17,7 [10,3; 24,4], p<0,01) under the influence of anticoagulants in the moderate subgroup compared with point 1 was observed. We didn't observe such phenomenon in severe subgroup.There was no significant difference in platelet aggregation between subgroups at point 1. During the course of the disease the patients in the moderate and severe subgroups demonstrated a significant increase in platelet aggregation induced by arachidonic acid and ADP (severe: AUC ARA 48,0 [25,0; 59,0] vs 77,5 [55,8; 92,7], p=0,04; AUC ADP 44,0 [41,0; 56,0] vs 58,0 [45,5; 69,0], p=0,04; moderate: AUC ARA 31,5 [19,8; 50,7] vs 56,0 [39,0; 76,0], p=0,01; AUC ADP 43,0 [20,0; 59,0] vs 56,6 [50,3; 70,5], p=0,04;), in moderate subgroup the significant increase in TRAP-induced aggregation was also noted (AUC TRAP 58,0 [41,0; 69,5] vs 76,0 [58,3; 81,5], p=0,048).There were no significant differences in the FMD-test results between the patient subgroups. FMD-test results were predominantly within the reference ranges (7,1 [4,0; 8,8]).Patients in the severe subgroup had significantly higher levels of vWF: Ag (228,0 [205,3; 240,7] vs 232,0 [226,0; 423,0], p=0,03).ConclusionSARS-CoV-2 infection was characterized by increased levels of vWF:Ag, that could represent the local endothelial damage, meanwhile there was no generalized endothelial dysfunction assessed via FMD-test in moderate to severe patients. At the same time the enhanced plasma coagulation in COVID-19 patients was observed.FUNDunding AcknowledgementType of funding sources: None.

Thrombogenicity of Hyaluronic Acid Fillers: A Quantitative Thrombodynamics Study.

At present, there is a paucity of data regarding the thrombogenicity of hyaluronic acid fillers (HAFs). This article quantitatively analyses the thrombogenicity of 2 commonly used HAFs: Restylane Lyft and Juvéderm Ultra. Thrombogenicity was assessed using the Thrombodynamics Analyzer System and plasma obtained from healthy controls. Following the addition of HAFs or control, spontaneous clot formation time, initial rate of clot growth, average rate of clot growth over 30 minutes, and clot size at 30 minutes was measured for each sample. The median of differences between each group were analyzed. Nine individuals with a mean (SD) age of 37 (17) years, participated in the study. Initial rate of clot growth was significantly lower in plasma mixed with Juvéderm compared to control (p = 0.008) or Restylane (p = 0.038). The average rate of clot growth more than 30 minutes was significantly lower in both HAF groups (Restylane vs. control p = 0.038; Juvéderm vs. control p = 0.008), there was no significant difference between HAF groups (p = 0.635). Final clot size was significantly smaller with Juvéderm (p = 0.038 vs. control and p = 0.013 vs. Restylane). Spontaneous clot formation time did not significantly change with the addition of either HAF. Juvéderm significantly reduces the initial rate of clot growth, the average rate of clot growth more than 30 minutes, and clot size, whereas the addition of Restylane decreases the average rate of clot growth without affecting overall clot size in healthy individuals.