Clot Growth Research Articles

Systematic mapping of the conformational landscape and dynamism of soluble fibrinogen

BackgroundFibrinogen is a soluble, multisubunit, and multidomain dimeric protein, which, upon its proteolytic cleavage by thrombin, is converted to insoluble fibrin, initiating polymerization that substantially contributes to clot growth. Fibrinogen contains numerous, transiently accessible “cryptic” epitopes for hemostatic and immunologic proteins, suggesting that fibrinogen exhibits conformational flexibility, which may play functional roles in its temporal and spatial interactions. Hitherto, there have been limited integrative approaches characterizing the solution structure and internal flexibility of fibrinogen. MethodsHere, utilizing a multipronged, biophysical approach involving 2 solution-based techniques, temperature-dependent hydrogen-deuterium exchange mass spectrometry and small angle X-ray scattering, corroborated by negative stain electron microscopy, we present a holistic, conformationally dynamic model of human fibrinogen in solution. ResultsOur data reveal 4 major and distinct conformations of fibrinogen accommodated by a high degree of internal protein flexibility along its central scaffold. We propose that the fibrinogen structure in the solution consists of a complex, conformational landscape with multiple local minima. This is further supported by the location of numerous point mutations that are linked to dysfibrinogenemia and posttranslational modifications, residing near the identified fibrinogen flexions. ConclusionThis work provides a molecular basis for the structural “dynamism” of fibrinogen that is expected to influence the broad swath of its functionally diverse macromolecular interactions and fine-tune the structural and mechanical properties of blood clots.

Fbg αC 389-402 enhances factor XIII crosslinking in the fibrinogen αC region via electrostatic and hydrophobic interactions.

Coagulation Factor XIII (FXIII) hinders fibrinolysis via transglutaminase activity in fibrin and other proteins. FXIII activity in the fibrinogen αC region (Fbg αC 221-610) is critical for clot stability and growth. Fbg αC 389-402 acts as a binding site for thrombin-activated FXIII, (FXIII-A∗), with αC E396 promoting FXIII-A∗ binding and activity. The current study aimed to discover additional residues within Fbg αC 389-402 that accelerate transglutaminase activity toward αC (233-425). αC E395 and D390 were proposed to form ionic interactions with FXIII that improve binding. αC W391 and F394 were hypothesized to augment FXIII-fibrinogen αC binding through favorable hydrophobic contacts with FXIII residues. Truncated Fbg αC 328-425 was also examined for any potential impact on FXIII activity. Fbg αC D390, W391, F394, E395, E396, and residues 328-425 were studied by select mutations to recombinant Fbg αC 233-425. FXIII activity was quantified by monitoring glycine ethyl ester (GEE) crosslinking to αC Q237 over time by mass spectrometry. Truncation mutations “403 Stop” (Fbg αC 233-402), “389 Stop” (Fbg αC 233-388), and “328 Stop” (Fbg αC 233-327) experienced reduced Q237-GEE crosslinking compared to wild-type (WT). Comparable crosslinking between “389 Stop” and “328 Stop” shows that FXIII is mainly affected by the loss of Fbg αC 389-402. Substitution mutations E396A, D390A, W391A, and F394A decreased crosslinking relative to WT, whereas E395A, E395S, E395K, and E396D had no effect. Similar FXIII-A∗ activities were observed for double mutants (D390A,E396A) and (W391A,E396A), relative to D390A and W391A, respectively. In contrast, crosslinking was further reduced in (F394A,E396A), relative to F394A. In conclusion, Fbg αC 389-402 boosts FXIII activity in Fbg αC, with D390, W391, and F394 identified as additional residues that enhance αC crosslinking.

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<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.

Combining Computational Modelling and Machine Learning to Identify COVID-19 Patients with a High Thromboembolism Risk

Severe acute respiratory syndrome of coronavirus 2 (SARS-CoV-2) is a respiratory virus that disrupts the functioning of several organ systems. The cardiovascular system represents one of the systems targeted by the novel coronavirus disease (COVID-19). Indeed, a hypercoagulable state was observed in some critically ill COVID-19 patients. The timely prediction of thrombosis risk in COVID-19 patients would help prevent the incidence of thromboembolic events and reduce the disease burden. This work proposes a methodology that identifies COVID-19 patients with a high thromboembolism risk using computational modelling and machine learning. We begin by studying the dynamics of thrombus formation in COVID-19 patients by using a mathematical model fitted to the experimental findings of in vivo clot growth. We use numerical simulations to quantify the upregulation in the size of the formed thrombi in COVID-19 patients. Next, we show that COVID-19 upregulates the peak concentration of thrombin generation (TG) and its endogenous thrombin potential. Finally, we use a simplified 1D version of the clot growth model to generate a dataset containing the hemostatic responses of virtual COVID-19 patients and healthy subjects. We use this dataset to train machine learning algorithms that can be readily deployed to predict the risk of thrombosis in COVID-19 patients.

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.

In vitro comparison of spatiotemporal fibrin clot formation dynamics in plasma treated with different protamine-heparin ratios.

Our study aim was to explore how different protamine-heparin ratios impacted enzymatic coagulation and acellular fibrin clot growth in plasma using an in vitro model. We hypothesized that a low protamine-heparin ratio would be associated with superior fibrin clot growth dynamics. We performed an in vitro study using 15 plasma samples from a commercial supplier. Different protamine-heparin ratios were added to each donor plasma sample: low ratio (0.7-1), traditional ratio (1-1), and high ratio (1.3-1) and clot formation dynamics were evaluated using a Thrombodynamics analyzer. Study outcomes were initial clot growth velocity and clot size at 30min. Plasma samples treated with a one-to-one protamine-heparin ratio had significantly lower mean initial clot growth velocity compared to samples treated with a low protamine-heparin ratio; mean difference -2.3μm/min (95% CI = -4.0 to -0.7, p = .004). Plasma samples treated with a one-to-one protamine-heparin ratio also had significantly smaller mean clot size at 30min compared to samples treated with a low protamine-heparin ratio; mean difference -54.0μm (95% CI = -107.6 to -0.4, p = .048). There were no significant differences in mean initial clot growth velocity or clot size at 30min between plasma samples treated with a high protamine-heparin ratio and those treated with a one-to-one or low protamine-heparin ratio (all p > .05). Plasma samples treated with a low protamine-heparin ratio had superior clot growth velocity and larger clot size at 30min compared to a one-to-one ratio, supporting the notion that a low protamine-heparin ratio may optimize enzymatic coagulation after cardiopulmonary bypass.

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.

Proposal of an in vitro thrombus-growth model for evaluating anticoagulants.

The general anticoagulant evaluation requires high expense equipment, reagents, and space. Therefore, not all laboratories can perform research related to anticoagulant. In this study, we propose a novel simple method "in vitro thrombus-growth model" that can evaluate anticoagulant ability by measuring weight. The in vitro thrombus-growth model is prepared by creating a "growth-clot" with citrate plasma, calcium chloride, and thrombin, and then pouring new citrate plasma onto it. The prepared growth-clots were increased in volume in citrated human plasma, including surpluses calcium chloride, which was released slowly, leading to clot coagulation around the plasma. As a result of evaluating the anticoagulant ability of direct thrombin inhibitor using this in vitro thrombus-growth model, it was confirmed that clot growth was suppressed in a concentration-dependent manner. Therefore, this thrombus-growth model is useful as a primary anticoagulant test that can to discover compounds with anticoagulant activity perform in any laboratory.

A Mechano-Chemical Computational Model of Deep Vein Thrombosis

Computational models of deep vein thrombosis (DVT) typically account for either the mechanical or biochemical factors involved in thrombus formation. Developing a model that accounts for both factors will improve our understanding of the coagulation process in this particular disease. The work presented in this study details the development of a CFD model that considers the biochemical reactions between thrombin and fibrinogen, pulsatile blood flow, and clot growth within a three-dimensional patient-specific common femoral vein. Thrombin is released into the bloodstream from an injury zone on the wall of the vein. The Michaelis–Menten equation is used to represent the conversion of thrombin and fibrinogen to fibrin, the final product of the coagulation process. The model development starts with a two-dimensional idealized geometry. At this stage, the model is used to conduct a parametric study to determine the effects of varying parameters such as inlet velocity, vein diameter, and peak thrombin concentration on the size and shape of the clot formed. Peak thrombin concentration is the key factor driving the initiation and propagation of clots in the vein. To demonstrate the potential use of the model, the two-dimensional model is then extended to an image-derived three-dimensional patient-specific geometry. Realistic clot growth was achieved using this model, and the clot was compared to a clot formed in vivo. The volume of the clot that formed in the patient was about 4% smaller than that formed in the simulation. This demonstrates that with further development and refinement, this model could be used for patient-specific interventional planning. The model provides a means for predicting clot formation under different physiological conditions in a non-invasive manner.

Treatment Outcomes of Regenerative Endodontic Procedures in Traumatized Immature Permanent Necrotic Teeth: A Retrospective Study

IntroductionThis retrospective study aimed to evaluate the clinical and radiographic outcomes of regenerative endodontic procedures (REPs) for traumatic immature permanent teeth. Meanwhile, predictors influencing treatment outcomes were also analyzed to provide evidence for the management of immature teeth after different traumatic scenarios. MethodsTraumatized immature permanent teeth diagnosed with pulp necrosis treated by REPs using blood clot or concentrated growth factor scaffolds with at least 6 months of follow-up were included from 2012 to 2021. Treatment outcomes were categorized as a success or failure and survival. Further root development was assessed in terms of the percentage changes in the apical diameter, root length, and radiographic root area. Among different injury types, the clinical and radiographic outcomes of REPs were evaluated by the Fisher exact test and the Kruskal-Wallis test, respectively. Survival analysis and Cox regression analysis were performed to identify significant predictors affecting outcomes. ResultsSixty-two teeth with a mean of 22.3 months of follow-up satisfied the criteria, and 80.6% of the teeth had a successful outcome. A significant change was observed in a decrease of the apical diameter (69.3%) and an increase of the radiographic root area (22.6%) after REPs. Among different injury types, the success rates of REPs were as follows: fracture, 84.6%; luxation, 83.3%; combined injuries, 78.6%; and avulsion, 33.3% (P > .05). Fractured teeth had a significantly greater decrease of the apical diameter than combined injuries (P < .05). Avulsion was more prone to developing root resorption than fracture (P < .05). Scaffold was a significant predictor for success; a blood clot had a significantly reduced risk for failure than concentrated growth factor (hazard ratio = 16; 95% confidence interval, 2.1–125.2; P < .001). ConclusionsREPs provided satisfactory outcomes in traumatized immature permanent necrotic teeth. However, severe injuries, especially avulsion, should be determined carefully to perform REPs when resorption is expected. Scaffold selection may be an important consideration.

​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.

Ultrasound‐Responsive Nanopeptisomes Enable Synchronous Spatial Imaging and Inhibition of Clot Growth in Deep Vein Thrombosis (Adv. Healthcare Mater. 16/2021)

Nanoparticle Theranostics The image describes the history of different anticoagulants and diagnostics for clotting disorders, highlighting several decades without innovation. In contrast, the right side of the image depicts the development of new precision strategies, like the nanoparticle theranostic paradigm. This latter work is highlighted in article 2100520 by Scott H. Medina and co-workers. Cover design by Daryl Branford.

A COVID-Positive 52-Year-Old Man Presented With Venous Thromboembolism and Disseminated Intravascular Coagulation Following Johnson &amp; Johnson Vaccination: A Case-Study

The coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). Infection by the SARS-CoV-2 increases the risk for systematic multi-organ complications and venous, arterial thromboembolism. The need for an effective vaccine to combat the pandemic prompted the Centers for Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) to approve a nationwide distribution of the Ad26.COV2.S vaccine manufactured by Johnson & Johnson (J&J). The use of the vaccine was halted after reported cases of cerebral venous sinus thrombosis (CVST) and thrombocytopenia among recipients. Researchers have postulated these rare occurrences as potentially immune-triggered responses associated with complement-mediated thrombotic microangiopathy (TMA). Thrombotic complications and thrombocytopenia increase the risk for blood clot growth due to the inflammation of immune complexes by pro-thrombotic activation of anti-platelet antibodies.A 52-year-old man presented to the intensive care unit (ICU) with severe dyspnea. He required bilevel positive airway pressure (BiPAP) for supplemental oxygen therapy. Endotracheal intubation was performed due to his worsened respiratory deterioration. Lab results suggested respiratory failure due to decreased partial pressure of oxygen (pO2) and increased partial pressure of carbon dioxide (pCO2). Findings of elevated D‐dimer levels with decreased fibrinogen and thrombocytopenia with prolonged prothrombin clotting time were consistent for disseminated intravascular coagulation (DIC). Chest radiography displayed moderate to heavy bilateral airspace consolidations, consistent with multifocal pneumonia suspicious for COVID-19. A computed tomography angiogram (CTA) revealed a mildly enlarged right ventricle and interventricular septum consistent for right heart strain due to a saddle pulmonary embolism (PE) that extended into the main pulmonary lobar segmental arteries bilaterally. The patient was transferred to a higher-level (tertiary) care for radiology intervention to remove the pulmonary embolism found on his lungs.This patient presented with severe dyspnea secondary to massive PE and deep venous thrombosis (DVT) due to SARS-CoV2 infection following the administration of the J&J vaccine. Bilateral thrombus opacities and pulmonary emboli are consistent among COVID-19 patients by intravascular coagulation with increased prothrombin time and D-dimer concentration with a low platelet count. Adverse emboli growths with increased D-dimer and thrombocytopenia strikes a similarity in recipients of the AstraZeneca vaccine due to vaccine-induced immune thrombotic thrombocytopenia (VITT). Administrative use of the J&J vaccine resumed in May 2021. The FDA's reassurance stemmed from their conclusive findings that the vaccine's benefits far outweigh these rare developments, which account for less than 0.01% of the total recipient population. Nevertheless, a further detailed analysis must be conducted on the adverse thrombotic manifestations following adenoviral-based COVID-19 vaccines (J&J, AstraZeneca) compared to mRNA-based vaccines (Moderna, Pfizer) to assess causality with higher specificity.

Evaluation of Hemostasis with the Thrombodynamics Test Improves Predictability of the Caprini Score for Postoperative DVT

Aim. To compare predictability for postoperative deep vein thrombosis (DVT) of the classic Caprini 2005 risk assessment model (RAM) and its modified version, considering the results of Thrombodynamics test (TD) in surgical patients at high risk.Methods. This was a prospective observational clinical study involving 80 patients (33 men and 47 women, mean age - 73,9±7,2 years), undergoing major (79 cases) or minor (1 case) surgery for colorectal cancer. Patients were at high risk of postoperative venous thromboembolism: 5-15 Caprini scores (mean - 9,9±2,0) and received combined prophylaxis: anti-embolic above-knee compression stockings and low-molecular-weight heparin (LMWH) injections (enoxaparin 40 mg once daily) until discharge. LMWH was administered in a fixed hour according to the time of blood shambling for TD. Before and after the surgery (0 day, 5-7 day and 1 month) duplex ultrasound was performed to detect postoperative DVT.Results. DVT was found in 21 of 80 patients (26.3%; 95% CI: 17,9-36,8%) at 5-7 day after surgery. No new venous thromboembolism events were detected at 1 month. Regression analysis and ROC-curve showed a significant predictability of Caprini scores for DVT (p<0,0001, S=0,839±0,045). Analysis of ROC-curve coordinates showed a cut-off point of 11 scores, which with the sensitivity of 76.2% and a specificity of 74.6% predicted DVT.The results of TD test showed significant hypercoagulation at the background of LMWH administration in patients with DVT. Regression analysis and ROC-curves demonstrated that TD parameters as stationary velocity of clot growth, measured at 2 hours after surgery (Vst), and initial velocity of clot growth, measured 24 hours after the LMWH injection (Vin), had the greatest predictability for postoperative DVT: S=0,764 ± 0,109, p=0,049 and S=0,946±0,047, p=0,001, respectively. The cut-off points for DVT prediction with high sensitivity/specificity appeared to be Vst>32,5 (normal range 20-29) µm/min and Vin>64,5 (normal range 36-56) µm/min.Identified thresholds for TD parameters have been integrated into Caprini RAM under the item “other congenital or acquired thrombophilia” (score of 3). Total Caprini scores were recalculated in patients who had one or both TD parameters exceeded the cut-off, followed by re-analysis of the ROC-curves. It was found that the Caprini RAM with integrated Vin>64,5 µm/min characterized by the highest predictability for DVT (S=0,876±0,038, p<0,0001) and increased cut-off up to 12 scores with sensitivity of 85,7% and specificity of 72.9%.Conclusions. The integration of TD parameters into Caprini RAM allows increasing predictability for postoperative DVT. DisclosuresLobastov:“Gemakor Labs” Ltd: Honoraria, Research Funding; “BEHO+” Ltd: Honoraria, Research Funding. Dementieva:“Gemakor Labs” Ltd: Honoraria, Research Funding. Soshitova:“Gemakor Labs” Ltd: Employment. Laberko:“Gemakor Labs” Ltd: Honoraria, Research Funding; “BEHO+” Ltd: Honoraria. Rodoman:“Gemakor Labs” Ltd: Research Funding.

Ultrasound‐Responsive Nanopeptisomes Enable Synchronous Spatial Imaging and Inhibition of Clot Growth in Deep Vein Thrombosis

Deep vein thrombosis (DVT) is a life-threatening blood clotting condition that, if undetected, can cause deadly pulmonary embolisms. Critical to its clinical management is the ability to rapidly detect, monitor, and treat thrombosis. However, current diagnostic imaging modalities lack the resolution required to precisely localize vessel occlusions and enable clot monitoring in real time. Here, we rationally design fibrinogen-mimicking fluoropeptide nanoemulsions, or nanopeptisomes (NPeps), that allow contrast-enhanced ultrasound imaging of thrombi and synchronous inhibition of clot growth. The theranostic duality of NPeps is imparted via their intrinsic binding to integrins overexpressed on platelets activated during coagulation. The platelet-bound nanoemulsions can be vaporized and oscillate in an applied acoustic field to enable contrast-enhanced Doppler ultrasound detection of thrombi. Concurrently, nanoemulsions bound to platelets competitively inhibit secondary platelet-fibrinogen binding to disrupt further clot growth. Continued development of this synchronous theranostic platform may open new opportunities for image-guided, non-invasive, interventions for DVT and other vascular diseases.