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Sticky platelet syndrome is a less known platelet function disorder with a familiar occurrence and likely genetic background. Clinically, it is characterized by an increased risk of venous and arterial thromboembolic events and obstetric placenta-mediated complications. The increased aggregation after low-dose ADP and/or epinephrine is its distinctive laboratory feature. Though described for almost 40 years, several issues regarding its etiology, involved pathomechanisms, genetic background, optimal diagnostic and treatment approach remain controversial.The work aims to summarize published studies, the actual definition of the syndrome, and point out its drawbacks. A literature search on Medline, Embase, and archives from EHA congresses was performed (terms: 'sticky platelet syndrome' - 'platelet hyperreactivity' - 'platelet hyperaggregability'). The authors added in their unpublished data. The introductory overview of the present understanding is followed by the discussion of the pathophysiologic, diagnostic, and therapeutic problems.Despite the growing evidence provided by case reports and series, the lack of robust studies limits the decision-making on diagnostics and management. The diagnostic issues, particularly the standardization of light transmission aggregometry, represent the crucial problem for the broader acceptance of the syndrome.PLAIN LANGUAGE SUMMARY Sticky platelet syndrome is aplatelet function disorder. It is associated with an increased risk of venous thromboembolism, arterial thrombosis, and obstetric placenta-mediated complications. Increased aggregation after low-dose ADP and/or epinephrine is the defining laboratory feature. Furthermore, afew studies report the familiar occurrence with possible genetic background. Several issues regarding the syndrome remain controversial: its exact etiology, genetics, optimal diagnostic, and treatment approach. These uncertainties provide ground for debate of the syndrome as aunique clinical entity. The review has two goals. Firstly, it summarizes the published studies and the actual definition of the syndrome. Secondly, it tries to point out the open pathophysiologic, diagnostic, and therapeutic problems.

Apixaban, a direct inhibitor of activated coagulation factor X (FXaI), is being frequently selected for treatment and prevention of venous thromboembolism (VTE). Several reports about possible use of oral FXaI in patients with cancer-associated VTE (CA-VTE) have been published recently.The efficacy/safety profile of oral FXaI anticoagulation in patients with CA-VTE seems promising; however, several problems remain unanswered. The pharmacologic profile of apixaban could prefer this agent for the treatment of CA-VTE.Currently available medical literature was searched and reviewed to summarize data regarding the use of apixaban for the prevention and treatment of cancer-associated VTE.Apixaban therapy in patients with cancer and VTE is expected to increase as clinicians gain more experience and reassurance with data from real-world studies that are generally promising. Several studies demonstrated that apixaban exhibits noninferiority to warfarin and low molecular weight heparin in preventing recurrent thrombosis in cancer-associated VTE. Nevertheless, there are still concerns regarding the bleeding associated with apixaban therapy, and regarding the optimal management of these bleeding emergencies.Although currently available evidence confirms the noninferiority of apixaban for reduction of the risk of recurrent VTE in patients with cancer; there are still concerns regarding the safety, especially in selected subpopulations of these patients.

Patients with atrial fibrillation (AF) on long-term direct oral anticoagulants (DOACs) may be at higher risk of bleeding because of higher anti-Xa or anti-IIa levels. However, there is no postmarketing study investigating these DOAC plasma levels at the time of bleeding. The aim of this study was to evaluate DOAC levels at the time of a bleeding emergency. We analyzed 5440 patients examined at our Emergency Department in from April 1, 2019, to September 30, 2019. During this period, we prospective identified 105 consecutive patients with bleeding while on long-term antithrombotic therapy; 49 patients had AF on DOACs. We compared DOAC levels in patients who bled against a control sample of 55 patients who tolerated long-term high dose DOAC therapy without any emergency. Samples of these patients were tested with drug-specific anti-Xa chromogenic analysis (rivaroxaban and apixaban) and with Hemoclot Thrombin Inhibitor assay (dabigatran). Dabigatran-treated patients who bled had significantly higher anti-IIa levels when compared with trough (261.4 ± 163.7 vs. 85.4 ± 57.2 ng/mL, P < 0.001) and peak samples of controls (261.4 ± 163.7 vs. 138.8 ± 78.7 ng/mL, P < 0.05). Similarly, there were significantly higher anti-Xa levels in rivaroxaban-treated and apixaban-treated patients with bleeding compared with trough control samples (rivaroxaban: 245.9 ± 150.2 vs. 52.5 ± 36.4 ng/mL, P

Direct oral anticoagulants (DOACs) are increasingly used worldwide for the prevention of stroke in patients with atrial fibrillation and to prevent or treat venous thromboembolism. In situations such as serious bleeding, the need for urgent surgery/intervention or the management of a thromboembolic event, the laboratory measurement of DOACs levels or anticoagulant activity may be required. Rotational thromboelastometry (ROTEM) is a viscoelastic hemostatic assay (VHA) which has been used in emergencies (trauma and obstetrics), and surgical procedures (cardiac surgery and liver transplants), but experience with this assay in DOACs-treated patients is still limited. This article reviews the use of ROTEM in the setting of DOACs therapy, focusing on DOACs-associated bleeding and the use of this VHA for the management of reversal strategies for DOACs-associated anticoagulation.

Edoxaban is an oral anticoagulant drug and a direct factor Xa inhibitor. However, it is still not fully understood if and how edoxaban impacts platelet function. This prospective study aimed to assess in vitro platelet function in patients with atrial fibrillation (AF) receiving edoxaban. It was a single centre study quantifying platelet aggregation in 20 patients treated with edoxaban by light transmission aggregometry. The thrombin receptor activating peptide (TRAP)-induced platelet aggregation was significantly lower 2 h after taking edoxaban compared to baseline value (44.7 ± 32.03% vs. 73.3 ± 25.55%; p

Congenital dysfibrinogenemia (CD) is a rare disorder of hemostasis. The majority of cases are caused by heterozygous missense mutations in one of the three fibrinogen genes. Patients with CD may experience bleeding and thrombosis, but many are asymptomatic. To better describe the clinical, laboratory, and genotypic picture of CD, we evaluated 31 patients from seven unrelated families using standard coagulation tests and genetic analysis. The clinical phenotype consisted of bleeding in 13/31 (42%) patients; other patients (18/31; 58%) were asymptomatic. Among patients with bleeding, symptoms were mostly in single anatomical sites, with variable intensity of bleeding. Compared to results from a previous large systematic survey, our results showed a similar mean bleeding score, but a higher incidence of bleeding episodes without thrombotic complications. In the present study, we identified three known pathogenic point mutations in the FGA (c.95G > A, c.104G > A) and FGB (c.586C > T) genes. The variants of CD identified in this cross-sectional study were either asymptomatic or had bleeding manifestations and showed similar laboratory features, irrespective of genotype. Results from genetic and clinical studies will continue to yield valuable information on the structure and function of the fibrinogen molecule.

The antiphospholipid antibodies (aPL) are commonly associated with thrombotic events and obstetric complications. However, apart from the bleeding complications of antithrombotic therapy, the acquired coagulopathy caused by the aPL, particularly by lupus anticoagulant and anticardiolipin antibodies, might be occasionally manifested as a hemorrhagic syndrome with various clinical severity. Bleeding symptoms vary from mild (mucocutaneous) up to life-threatening (gastrointestinal, intracranial). The bleeding may be the first manifestation of aPL or appear concomitantly with thrombosis. The underlying hemostatic changes include thrombocytopenia, platelet function disorders, and coagulation factor inhibitors or deficiencies, namely prothrombin, FVII, FVIII, FX, and FXI. Thrombocytopenia is the most common finding, seen in up to 53% of patients with aPL, although it is usually mild to moderate and associated with significant bleeding only in a minority of cases. Of interest, patients with severe thrombocytopenia appear to be less likely to suffer from thrombotic events. The involved pathophysiological mechanisms are heterogeneous. Non-neutralizing antibodies against coagulation factors resulting in increased clearance, specific antibodies against platelet membrane glycoproteins, increasing platelet activation and aggregation with subsequent consumption, and immune-mediated platelet clearance are among those identified. Immunosuppression, preferably with corticosteroids, represents the first-choice therapeutic approach. Plasmapheresis is efficient in the case of catastrophic antiphospholipid syndrome. Antithrombotic therapy can be challenging, but its administration should continue as much as possible.

The deficiency of natural anticoagulants—antithrombin (AT), protein C (PC), and protein S (PS)—is a highly predisposing factor for thrombosis, which is still underdiagnosed at the genetic level. We aimed to establish and evaluate an optimal diagnostic approach based on a high-throughput sequencing platform suitable for testing a small number of genes. A fast, flexible, and efficient method involving automated amplicon library preparation and target sequencing on the Ion Torrent platform was optimized. The cohort consisted of a group of 31 unrelated patients selected for sequencing due to repeatedly low levels of one of the anticoagulant proteins (11 AT-deficient, 13 PC-deficient, and 7 PS-deficient patients). The overall mutation detection rate was 67.7%, highest in PC deficiency (76.9%), and six variants were newly detected—SERPINC1 c.398A > T (p.Gln133Leu), PROC c.450C > A (p.Tyr150Ter), c.715G > C (p.Gly239Arg) and c.866C > G (p.Pro289Arg), and PROS1 c.1468delA (p.Ile490fs) and c.1931T > A (p.Ile644Asn). Our data are consistent with those of previous studies, which mostly used time-consuming Sanger sequencing for genotyping, and the indication criteria for molecular genetic testing were adapted to this process in the past. Our promising results allow for a wider application of the described methodology in clinical practice, which will enable a suitable expansion of the group of indicated patients to include individuals with severe clinical findings of thrombosis at a young age. Moreover, this approach is flexible and applicable to other oligogenic panels.

Congenital fibrinogen disorders are diseases associated with a bleeding tendency; however, there are also reports of thrombotic events. Fibrinogen plays a role in the pathogenesis of thrombosis due to altered plasma concentrations or modifications to fibrinogen’s structural properties, which affect clot permeability, resistance to lysis, and its stiffness. Several distinct types of genetic change and pathogenetic mechanism have been described in patients with bleeding and a thrombotic phenotype, including mutations affecting synthesis or processing in three fibrinogen genes. In this paper, we focused on familial hypofibrinogenemia, a rare inherited quantitative fibrinogen disorder characterized by decreased fibrinogen levels with a high phenotypic heterogeneity. To begin, we briefly review the basic information regarding fibrinogen’s structure, its function, and the clinical consequences of low fibrinogen levels. Thereafter, we introduce 15 case reports with various gene mutations derived from the fibrinogen mutation database GFHT (French Study Group on Hemostasis and Thrombosis), which are associated with congenital hypofibrinogenemia with both bleeding and thrombosis. Predicting clinical presentations based on genotype data is difficult. Genotype–phenotype correlations would be of help to better understand the pathologic properties of this rare disease and to provide a valuable tool for the identification of patients who are not only at risk of bleeding, but also at risk of a thrombotic event.

von Willebrand disease (VWD) is reportedly the most common inherited bleeding disorder. This disorder develops as a result of defects and/or deficiency of the plasma protein von Willebrand factor (VWF). Laboratory testing for VWF-related disorders requires the assessment of both VWF level and VWF activity, the latter requiring multiple assays. As an additional step, an evaluation of VWF structural features by multimer analysis is useful in selective investigations. Multimer analysis is also important for the selection of a suitable VWF therapy preparation (desmopressin, VWF/FVIII concentrate, recombinant VWF) and the determination of the correct dose for the patient. Based on clinical and laboratory findings, including the analysis of VWF multimers, we classified our patients into individual types of VWD. Our study group included 58 patients. The study group consisted of 66% (38 patients) with VWD type 1, 5% (3 patients) with VWD type 2, 7% (4 patients) with VWD type 3, 5% (3 patients) with mixed type 1/2A VWD, and 17% (10 patients) comprising an unclassified group. In this article, we provide an overview of our practical experience using a new complementary method—the analysis of von Willebrand factor multimers with a semi-automatic analyzer Hydrasys 2 scan. We explain the principle, procedure, advantages, and pitfalls associated with the introduction of the VWF multimer analysis methodology into standard VWD diagnostics.

Aims We aimed to characterize relationship between the expression profiles of platelet miR-96, miR-126 and miR-223 and platelet function examination in patients with sticky platelet syndrome (SPS) and in healthy controls. Background MicroRNAs (miRNA, miR) are a group of small and non-coding RNAs involved in many mechanisms as regulators of post-transcriptional protein expression in platelets. SPS is defined as platelet hyperaggregability after administration of low doses of adenosine diphosphate and/or epinephrine. Clear genetic abnormality of this syndrome is not known yet. Methods We examined 45 patients with SPS and 30 healthy volunteers. For functional platelet examination we used light transmission aggregometry, and qRT-PCR was used to determine the expression of the miRNAs. Results We observed no relationship of the platelet miRNA expression with functional platelet examination in the entire cohort of patients with SPS. However, in a group of patients with SPS and pregnancy complications, we found that the expression of platelet miR-96 (p = 0.009) was up-regulated. Conclusion In spite of the multiple limitations of the study, it can be considered that the increased expression of platelet miR-96 found in a group of patients with SPS and pregnancy complications could be related to the hyperaggregability in these selected patients (Tab. 2, Ref. 31).

Introduction: Sticky platelet syndrome (SPS) is referred to as a platelet hyperaggregability triggered by low concentrations of platelet agonists adenosine diphosphate (ADP) and/or epinephrine (EPI). Platelet aggregation with other inducers (collagen, arachidonic acid, ristocetin, and thrombin) remains within a normal range. MicroRNAs (miRNAs) are small, non-coding RNA molecules that play an important role in post-transcriptional regulation of protein expression. More recently, several studies show that the platelets are an abundant source of miRNAs and that the miRNA expression profiles within platelets correlate with the platelet reactivity. Aim: The principle objective of this article is to describe the method which we developed for the preparation of the pure platelet samples and report the results of this method. These final pure platelet samples are intended to be the first step for the platelet miRNA testing. Methods: The blood samples from 50 subjects were examined in the study. Then, the platelet rich plasma (PRP) samples obtained by centrifugation of the patient blood samples were used for our experiments. Subsequently, the erythrocytes and leucocytes remaining in PRP sample were magnetically labelled by CD45 Microbeads and CD235a Microbeads. After incubation the PRP sample passed through the magnetic separation system and the magnetically labelled cells (erythrocytes and leucocytes) were retained within the column of separator. The number of cells in the final PRP samples was measured by the blood cell analyser. Results and conclusion: We successfully developed and optimized the effective and reproducible method for magnetic separation of platelets, resulting in the leukocyte-depleted and erythrocyte-depleted platelet samples, which can be used for further genetic analyses.

Oralna antitromboticka liecba u pacientov s akutnym koronarnym syndromom a u pacientov s fibrilaciou predsieni signifikantne zvysuje riziko gastrointestinalneho krvacania. Inhibitory protonovej pumpy podavane s protidostickovou a antikoagulacnou liecbou možu znižovať riziko gastrointestinalneho krvacania. V sucasnosti bolo do klinickej praxe uvedených niekoľko relativne nových antitrombotik u pacientov s akutnym koronarnym syndromom (klopidogrel, prasugrel, tikagrelor) alebo u pacientov s fibrilaciou predsieni vyžadujucich dlhodobu antikoagulaciu (dabigatran, rivaroxaban, apixaban, edoxaban). Tieto nove antitrombotika poskytuju silnejsiu inhibiciu dosticiek alebo antikoagulaciu v porovnani so starsimi preparatmi (tiklopidin, anopyrin, warfarin), preto sa zda, že potreba gastroprotekcie može byť silnejsia, keď su tieto nove preparaty podavane dlhodobo. Prave pre uvedene je tato konkomitantna terapia podavana relativne casto. V tejto praci sumarizujeme dostupne data o vplyve inhibitorov protonovej pumpy na riziko gastrointestinalneho krvacania asociovaneho s liecbou novými oralnymi antitrombotikami.

Very limited but promising experiences with the use of direct factor Xa inhibitors for the treatment of heparin-induced thrombocytopenia (HIT) have been reported. This contribution features our first experience with the use of apixaban (without a pre-treatment with parenteral anticoagulant) to treat a case of HIT which developed in a patient after multiple heart replacement surgery. Apixaban was effective, well tolerated and safe. An apixaban-calibrated chromogenic anti-Xa activity assessment was used to monitor apixaban activity throughout the therapy. Patient continued on apixaban for the prevention of thrombosis in the settings of atrial fibrillation. No ischemic or bleeding events occurred during the clinical follow up and the platelet count was stable. Our experience suggests that apixaban might be effectively used for the treatment of HIT and for the long-term prevention of embolism in patients after multiple valve replacement with biological prostheses and atrial fibrillation.

BACKGROUND Proton pump inhibition (PPI) administrated together with dabigatran reduces the risk of gastrointestinal hemorrhage. However, there is a discussion regarding possible PPI-dabigatran interaction that may reduce the efficacy of this therapy. STUDY QUESTION To determine the impact of concomitant PPI on dabigatran plasma levels in patients with nonvalvular atrial fibrillation (NV-AF). STUDY DESIGN A pilot prospective study in patients with NV-AF on dabigatran therapy was performed; 31 patients were enrolled. PPI with either omeprazole or pantoprazole was administrated in 19 patients. MEASURES AND OUTCOMES Blood samples were taken for the assessment of the dabigatran trough and peak levels. Dabigatran concentration was measured with the Hemoclot Thrombin Inhibitor Assay. RESULTS There were significant differences in dabigatran trough level comparing patients treated with PPI and patients without PPI (58.86 ± 36.76 ng/mL vs. 110.72 ± 88.47 ng/mL, P < 0.05). Similarly, there were significant differences in dabigatran peak level between compared groups (88.0 ± 20.5 ng/mL vs. 174.4 ± 139.64 ng/mL, P < 0.05). CONCLUSIONS This pilot study demonstrated the interaction between PPI and dabigatran levels in patients with NV-AF.

Genetic testing in patients with von Willebrand disease completes phenotypic testing with an aim to confirm the von Willebrand factor defect at a molecular level. Structure of the VWF gene was described 30 years ago; since then a large number of mutations leading to VWD have been described in this gene. Thanks to describing these mechanisms it is possible to understand the pathogenesis of the most common congenital bleeding disorder. In the Slovak Republic genetic testing is still not a routine part of VWD diagnostics. The National Center of Hemostasis and Thrombosis in Martin is the first department in Slovakia which has begun genetic testing of patients with VWD. Sequencing of the VWF gene has many limitations which are referred in more details within this article. Therefore, we decided to use the methods of new generation sequencing in combination with Sanger sequencing. We believe that soon we will have the first results which will help us to identify the possible cause of VWD in these patients.

Atorvastatin and direct oral factor Xa inhibitors (xabans) are frequently co‐administrated in patients with atrial fibrillation (AF). However, no studies investigating the possibility of the pharmacologic interaction between these agents have been conducted. The aim of this prospective observational study was to determine the impact of atorvastatin therapy on anti‐Xa activity in xabans‐treated patients with AF. We enrolled 115 AF patients on long‐term rivaroxaban (52 patients) and long‐term apixaban (63 patients) therapy. Long‐term atorvastatin (40 mg once daily) was administrated to 28 rivaroxaban‐treated patients and to 28 apixaban‐treated patients. Trough and peak samples were tested for anti‐Xa activity with drug‐specific anti‐Xa chromogenic analysis. For rivaroxaban, there were no significant differences in trough activity (45.5 ± 39.5 ng/ml vs. 46.2 ± 30.1 ng/ml; p = .34) and peak anti‐Xa activity (179.2 ± 108.8 ng/ml vs. 208.1 ± 104.1 ng/ml; p = .94) between atorvastatin‐treated patients and those without atorvastatin. Similarly, atorvastatin did not impact the trough activity (127.7 ± 71.1 ng/ml vs. 100.8 ± 61.1 ng/ml; p = .12) or peak anti‐Xa activity (213.8 ± 103.6 ng/ml vs. 179.3 ± 72.9 ng/ml; p = .14) among apixaban‐treated patients with AF. This observational study did not show a significant impact of atorvastatin on trough and peak anti‐Xa activity in xabans‐treated patients with AF.

Heparin-induced thrombocytopenia (HIT) is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to low-molecular weight heparin. Some patients with HIT develop serious thrombotic complications like limb ischemia and gangrene, while others may not develop such complications. Current laboratory diagnostic tools incur significant time delays before confirming HIT, therefore upon clinical suspicion, treatment of HIT should start immediately. In this review, the authors highlight heparin-induced thrombocytopenias risk factors, clinical presentation, pathophysiology, diagnostic principles, and treatment.

Thromboprophylaxis with low-molecular-weight heparin (LMWH) for patients with a history of venous thromboembolism (VTE) is suggested. Rotational thromboelastometry (ROTEM®) represents an innovative point-of-care method enabling the complex and quick evaluation of hemostasis. However, there are only episodic cases of its use for hemostasis assessment and guidance of LMWH in pregnancy. Therefore, we provide the results of unique prospective and longitudinal monitoring of hemostasis in high-risk pregnant women, which we used for the individualized optimalization of secondary thromboprophylaxis. According to the shortening of clot formation time (CFT) in EXTEM (p = 0.0007 from the 26th gestational week vs. controls) and INTEM (p = 0.002 from the 35th gestational week), increase in alpha angle (AA) in EXTEM, INTEM, and HEPTEM, and the persistence of increase in maximum clot firmness (MCF) in EXTEM, INTEM, and HEPTEM (p &lt, 0.001 from the 26th and 35th gestational week vs. controls for EXTEM and INTEM, p = 0.0012 from the 26th gestational week in HEPTEM), LMWH dose was modified. Even after the postpartum period, AA in EXTEM was steeper than in controls (p = 0.0007), indicating that hemostasis is not fully normalized after 6–8 weeks following delivery. Therefore, ROTEM may be a useful tool for the individual evaluation of the termination of anticoagulant thromboprophylaxis.

Platelets play crucial role in acute vascular atherosclerotic diseases, including myocardial infarction and stroke. Additionally, platelet aggregation is a key target of antiplatelet agents, forming the keystone of pharmacotherapy of various atherosclerotic cardiovascular diseases. Thromboelastography and thromboelastometry, representing currently available viscoelastic hemostatic assays (VHA), are designed as whole blood, real-time analyzers of clot formation and clot resolution. These assays could, in theory, overcome some limitations of currently available platelet function testing assays. This article reviews the current experience with the use of VHA for platelet function testing and for monitoring of the response to antiplatelet therapy.

A rapid and reliable assessment of the dabigatran effect is desirable in dabigatran treated patients with uncontrolled bleeding or before acute surgery. The aim of this study was to study the anticoagulant effects of dabigatran in patients with atrial fibrillation (AF) as assessed by the whole blood assays ROTEM, and how data from these methods correlate to plasma dabigatran concentrations measured by Hemoclot. ROTEM was performed with ROTEM Gamma (Pentapharm GmbH, Munich, Germany). The assays used in our study were Ex-tem and In-tem assay. Plasma dabigatran concentrations were determined by hemoclot thrombin inhibitor assay (Hyphen BioMed, France) at trough and post-dose in 27 patients on dabigatran 150 mg BID. Median plasma dabigatran concentrations at trough were 74 ng/mL (11.2–250) and post-dose (2 h after ingestion) 120 ng/mL (31–282). The ROTEM clotting time (CT) and maximum clot firmnes (MCF) correlated strongly with dabigatran concentrations when activated with the reagents Ex-tem (p < 0.0001) and In-tem (p < 0.0001). In summary, in our study, we have found that the ROTEM variable CT and MCF, when activated with triggers Ex-tem and In-tem, has a strong and highly significant correlation with the plasma dabigatran concentration in a real-life population of AF-patients and could thereby be an alternative to estimate dabigatran concentration in emergency situations. However, additional studies are needed to further validate these findings.

Introduction: Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired, life-threatening hemopoietic stem cell disorder characterized by the triad of hemolytic anemia, thrombosis, and impaired bone marrow function. Evidence suggests that severe outcomes in COVID19 infection are attributed to the excessive activation of the complement cascade leading to acute lung injury and associated is with an increased prothrombotic state. Patient concerns: A 27-year-old Caucasian man with PNH presented to the Emergency Department of our hospital with acute onset shortness of breath, cough and blood in urine. Diagnosis: The patient was diagnosed with acute hemolytic exacerbation of PNH complicated with moderate COVID19 pneumonia. Outcomes: The patient was initiated with an anticoagulant unfractionated heparin, dexamethasone, and cefuroxime injection. His symptoms quickly resolved, and he was discharged after 5 days. Conclusion: The complement system activation is a critical component in the sequalae of COVID19 infection. Evidence suggests that severe outcomes in COVID19 infection are attributed to the excessive activation of the complement cascade leading to acute lung injury and associated is with an increased prothrombotic state. Notably, C5a concentration was noted to be higher in patients with COVID19 infection. The use of complement inhibitors to attenuate immune mediated damage in COVID19 nevertheless represents a very interesting theoretical approach. However, careful consideration as to which patients may benefit will be required and the outcome of clinical trials needed.

Edoxaban, a direct factor Xa inhibitor (FXa), is the fourth direct oral anticoagulant (DOAC) approved for clinical use. As the main adverse event is bleeding, it is relevant whether edoxaban has additional effects on platelet function. We aimed to assess in vitro aggregation in patients with atrial fibrillation (AF) receiving edoxaban. We evaluated 20 AF patients treated with edoxaban. We assessed light transmittance platelet aggregation (LTA) with 100 nmol/L γ-thrombin. The LTA was performed at 2 time-points. The thrombin-induced platelet aggregation was significantly lower 2 hours after edoxaban was taken compared to baseline measurement (27.25% ± 30.8% vs. 60.35% ± 33.3%). In addition, we also performed 16 subanalyses in order to identify the differences in the outcome of different comorbidities, age, dosage, liver and kidney function tests, and concomitant treatment. Results of the subgroup analyses were consistent with the findings of the main analysis; there was no apparent heterogeneity across the prespecified subgroups. The thrombin-induced platelet aggregation is reduced in non-valvular AF patients receiving edoxaban.

AIMS The goal of this study was to compare the treatment outcome after two different treatment modalities in cases of disc displacement of the temporomandibular joint diagnosed via magnetic resonance technique, namely surgical procedure in form of arthroscopic lysis and lavage vs. hyaluronic acid superior joint space application. MATERIALS AND METHODS Magnetic resonance imaging was performed before and one year after treatment. Simultaneously, pre- and post-treatment visual analogue scales and maximal mouth opening distance were documented. RESULTS In our study, out of the total of 145 patients who were initially diagnosed with magnetic resonance imaging to have internal derangements and treated with arthroscopic lysis and lavage or hyaluronic acid application, we observed progression of internal derangement in 27 cases (18.6 %), improvement in 37 cases (25.5 %) and stationary state in 81 patients (55.9 %). Both treatment methods significantly improved the followed maximal mouth opening distance and visual analogue scale, as confirmed upon the 12‑month follow-up examination. Maximal mouth opening was 4.7mm for hyaluronic acid application and 12.2mm for arthroscopic lysis and lavage (p

Fibrinogen is a hexameric plasmatic glycoprotein composed of pairs of three chains (Aα, Bβ, and γ), which play an essential role in hemostasis. Conversion of fibrinogen to insoluble polymer fibrin gives structural stability, strength, and adhesive surfaces for growing blood clots. Equally important, the exposure of its non-substrate thrombin-binding sites after fibrin clot formation promotes antithrombotic properties. Fibrinogen and fibrin have a major role in multiple biological processes in addition to hemostasis and thrombosis, i.e., fibrinolysis (during which the fibrin clot is broken down), matrix physiology (by interacting with factor XIII, plasminogen, vitronectin, and fibronectin), wound healing, inflammation, infection, cell interaction, angiogenesis, tumour growth, and metastasis. Congenital fibrinogen deficiencies are rare bleeding disorders, characterized by extensive genetic heterogeneity in all the three genes: FGA, FGB, and FGG (enconding the Aα, Bβ, and γ chain, respectively). Depending on the type and site of mutations, congenital defects of fibrinogen can result in variable clinical manifestations, which range from asymptomatic conditions to the life-threatening bleeds or even thromboembolic events. In this manuscript, we will briefly review the main pathogenic mechanisms and risk factors leading to thrombosis, and we will specifically focus on molecular mechanisms associated with mutations in the C-terminal end of the beta and gamma chains, which are often responsible for cases of congenital afibrinogenemia and hypofibrinogenemia associated with thrombotic manifestations.

Proton pump inhibition (PPI) reduces gastrointestinal bleeding on direct oral anticoagulants. However, PPI may affect dabigatran on-treatment levels; and there is no information regarding the effect of PPI on xabans on-treatment activity. Thus, the aim of this study was to determine the impact of PPI on therapeutic anti-Xa activity in rivaroxaban- and apixaban-treated patients with atrial fibrillation (AF). This single-centre pilot prospective study enrolled 77 consecutive xabans-treated patients (42 rivaroxaban-treated and 35 apixaban-treated patients) with AF. PPI was administrated in 44 patients. Trough and peak anti-Xa activity was assessed with factor Xa-calibrated anti-Xa chromogenic analysis. There were no significant differences in trough anti-Xa activity comparing PPI-treated patients and patients without PPI (80.5 ± 66.5 ng/mL in PPI group vs. 71.6 ± 64.1 ng/mL in non-PPI group, p = 0.57, Table 2). Similarly, there were no significant differences in peak anti-Xa activity between compared groups (175.2 ± 102.5 ng/mL in PPI group vs. 202.9 ± 84.1 ng/mL in non-PPI group, p = 0.21). This pilot study did not reveal significant changes in xabans on-treatment anti-Xa activity according the PPI status.

Objectives: Several studies have questioned the need for platelet function testing in patients treated with new ADP receptor blockers (ADPRB). The aim of this study was to evaluate the prevalence of high on-treatment platelet reactivity (HTPR) among acute ST-elevation myocardial infarction (STEMI) patients treated with newer ADPRB. Methods: A prospective study enrolling 44 acute previously ADPRB naive STEMI patients (31 men, 13 women) undergoing primary percutaneous coronary intervention (pPCI) was performed. Among the studied population 23 patients received prasugrel and 21 patients received ticagrelor. Antiplatelet response was tested with light transmission aggregometry (LTA) and vasodilator-stimulated phosphoprotein phosphorylation (VASP-P) flow cytometry assay. Samples were taken prior to coronary angiography (sample 1) and on the day after this procedure (sample 2). Results: The mean platelet aggregation after induction with ADP was 51.7 ± 24.8% in sample 1 and 25.3 ± 20.1% in sample 2. An examination of VASP-P showed a mean platelet reactivity index of 56.8 ± 25.7% in sample 1 and 23.8 ± 23.1% in sample 2, respectively. The study identified 11.4% of patients in sample 2 as ADP receptor blocker non-responders. No significant differences were found between prasugrel-treated to ticagrelor-treated patients. Conclusions: This pilot study demonstrated HTPR among acute STEMI patients treated with newer ADPRB.

The monitoring of coagulation by viscoelastometric methods—thromboelastography and rotational thromboelastometry—may detect the contributions of cellular and plasma components of hemostasis. These methods might overcome some of the serious limitations of conventional laboratory tests. Viscoelastic testing can be repeatedly performed during and after surgery and thus provides a dynamic picture of the coagulation process during these periods. Several experiences with the use of these methods in cardiovascular surgery have been reported, but there is perspective for more frequent use of these assays in the assessment of platelet response to antiplatelet therapy and in the assessment of coagulation in patients on long-term dabigatran therapy. This article reviews the current role and future perspectives of thromboelastography and thromboelastometry in the management of cardiovascular diseases.

The aim of this study was to evaluate the genetic variability of the selected single nucleotide polymorphisms (SNPs) and examine the association between these SNPs and risk for deep vein thrombosis (DVT) in patients with sticky platelet syndrome (SPS). We examined 84 patients with SPS and history of DVT and 101 healthy individuals. We were interested in 2 SNPs within platelet endothelial aggregation receptor 1 (PEAR1) gene (rs12041331 and rs12566888), 2 SNPs within mkurine retrovirus integration site 1 gene (rs7940646 and rs1874445), 1 SNP within Janus kinase 2 gene (rs2230722), 1 SNP within FCER1G gene (rs3557), 1 SNP within pro-platelet basic protein (rs442155), 4 SNPs within alpha2A adrenergic receptor 2A (ADRA2A; rs1800545, rs4311994, rs11195419, and rs553668), and 1 SNP within sonic hedgehog gene (rs2363910). We identified 2 protective SNPs within PEAR1 gene and 1 risk SNP within ADRA2A gene (PEAR1: rs12041331 and rs12566888; ADRA2A: rs1800545). A haplotype analysis of 4 SNPs within ADRA2A gene identified a risk haplotype aagc ( P = .003). Moreover, we identified 1 protective haplotype within PEAR1 gene (AT, P = .004). Our results support the idea that genetic variability of PEAR1 and ADRA2A genes is associated with platelet hyperaggregability manifested as venous thromboembolism. The study also suggests a possible polygenic type of SPS heredity.

Aims: The aim of this study was to asses the platelet activation in the acute phase of ischemic stroke and transient ischemic attack (TIA) by defining p-selectin (CD62) expression by flow cytometry in vivo – without stimulation with agonists. We also studied whether antiplatelet therapy supresses the levels of baseline p-selectin expression and verified if there is a correlation between platelet CD62 expression and the type of ischemic stroke. Methods: We determined the expression of platelet surface p-selectin using whole-blood flow cytometry within the first 48-hours after onset of cerebral symptoms in patients with atherothrombotic and lacunar ischemic stroke and in healthy volunteers. We studied the realationship between antiplatelet medication and the type of ischemic stroke to baseline p-selectin expression. Results: Patients with acute cerebral ischemia have an excess of circulating platelets that express p-selectin, compared to healthy volunteers. The difference between average p-selectin expression in the group of healthy volunteers and the group of patients with stroke was statistically significant (p-value < 0,000001). Patients with stroke without antiplatelet medication showed a higher p-selectin expression than patients with antiplatelet medication (ASA, CLP, or ASA and CLP), hovewer, the difference was not statistically significant. There is no relationship between CD62 expression and the type of stroke. Conclusions: We can conclude that p-selectin is a highly sensitive blood biomarker of increased platelet activation. Antiplatelet therapy suppresses baseline p-selectin expression only minimally, insignificantly according to our results.

Dabigatran is a direct thrombin inhibitor. As the main adverse event is bleeding, it is relevant whether dabigatran has additional effects on platelet function. If so, it could affect the bleeding risk. We aimed to assess in vitro aggregation in patients with atrial fibrillation (AF) receiving dabigatran.We evaluated 32 AF patients treated with dabigatran (study group) and 18 non-anticoagulated non-AF blood donors (control group). We assessed light transmittance platelet aggregation (LTA) with 100 nmol/L γ-thrombin in both groups. The LTA was performed at two time-points in our dabigatran group of patients.The thrombin-induced platelet aggregation was significantly lower two hours after dabigatran was taken compared to baseline measurement (9% ± 6% vs. 29% ± 21%) in our study group. Moreover, we observed that the baseline value of platelet aggregation in patients on dabigatran treatment was significantly lower compared to healthy volunteers (29% ± 21% vs. 89 ± 8). However, one subanalysis showed that this significant reduction in platelet aggregation at baseline was only observed in patients who received dabigatran for over a week.The thrombin-induced platelet aggregation is reduced in non-valvular AF patients receiving dabigatran after a week-long therapy.

The number of elderly individuals with non-valvular atrial fibrillation (NV-AF) requiring long-term anticoagulation is rising. The pharmacokinetics of oral anticoagulants in elderly individuals may differ from that for younger patients. The aim of this study was to assess the dabigatran levels in elderly patients with NV-AF. A pilot prospective post-marketing study in patients with NV-AF on dabigatran therapy was performed; we enrolled 21 consecutive elderly patients (aged ≥ 75 years) on a reduced dabigatran regimen (110 mg twice daily) and compared them with 13 younger (≤ 70 years) individuals on reduced dabigatran therapy due to renal impairment and with 16 younger patients on standard dabigatran therapy (150 mg twice daily). Blood samples were taken for the assessment of dabigatran trough and peak levels. Dabigatran levels were measured with the Hemoclot® Thrombin Inhibitor Assay. There were significant differences in dabigatran trough levels when comparing elderly patients on reduced dabigatran with non-elderly patients on reduced dabigatran (99.3 ± 73.6 vs 51.6 ± 25.6 ng/mL; p

Low-molecular-weight heparin (LMWH) is suggested for thromboprophylaxis in pregnant women with previous venous thromboembolism (VTE). Anyway, there is only limited amount of studies evaluating the effect of LMWH on hemostatic parameters during pregnancy of patients with previous VTE and the need of secondary thromboprophylaxis. We therefore provide results of prospective and longitudinal assessment of changes in hemostasis in high-risk pregnant women at four times during pregnancy (T1–T4) and one time after the postpartum period (T5) used for individualized modification of thromboprophylaxis. In this study, the results of coagulation factor VIII (FVIII) and protein S (PS) activity, ProC Global ratio and anti-Xa activity were evaluated. Despite the thromboprophylaxis, an increased predisposition to thromboembolic complications was detected (significant increase in FVIII activity and decrease in PS function, ProC Global ratio not normalized even after the postpartum period – p

Aims Type 2 diabetes (T2D) is connected with several abnormalities in haemostasis; and with higher risk of stroke and systemic embolism in patients with non-valvular atrial fibrillation (NV-AF). However, it is recently unknown whether T2D affects the activity of direct oral anticoagulants (DOACs). The aim of this study was to determine the impact of T2D on DOACs activity in patients with NV-AF. Methods This pilot prospective study enrolled totally 65 patients with NV-AF (20 dabigatran-treated, 110 mg/twice daily; 28 rivaroxaban-treated, 15 mg/daily; 17 apixaban-treated, 5 mg/twice daily). 25 patients had T2D (8 dabigatran-treated, 11 rivaroxaban-treated, and 6 apixaban-treated). DOAC activity was tested with Hemoclot® Thrombin Inhibitor assay in dabigatran-treated patients, and with factor Xa-calibrated anti-Xa chromogenic analysis in rivaroxaban- and apixaban-treated patients prior and two hours after drug administration. Results There were no significant differences in dabigatran baseline (62.1 ± 8.0 vs. 51.8 ± 38.9 ng/ml, p = .76) and 2-h-post-drug-administration (91.7 ± 57.2 vs. 72.2 ± 33.2 ng/ml, p = .48) activity comparing T2D and non-diabetic patients. Similarly, no significant differences were found in rivaroxaban baseline (35.9 ± 22.5 vs. 55.3 ± 45.1 ng/ml, p = .19) and 2-h-post-drug-administration (145.7 ± 74.1 vs. 202.6 ± 135.0 ng/ml, p = .22) anti-Xa activity. In addition, no significant differences were present in apixaban baseline (96.0 ± 54.5 vs. 63.9 ± 36.8 ng/ml, p = .24) and 2-h-post-drug-administration (151.0 ± 78.3 vs. 151.7 ± 59.1 ng/ml, p = .98) anti-Xa activity between T2D and non-diabetic patients. Conclusions This pilot study did not detect differences in DOACs activity according to T2D status in patients with NV-AF.

Congenital fibrinogen disorders are rare pathologies of the hemostasis, comprising quantitative (afibrinogenemia, hypofibrinogenemia) and qualitative (dysfibrinogenemia and hypodysfibrinogenemia) disorders. The clinical phenotype is highly heterogeneous, being associated with bleeding, thrombosis, or absence of symptoms. Afibrinogenemia and hypofibrinogenemia are the consequence of mutations in the homozygous, heterozygous, or compound heterozygous state in one of three genes encoding the fibrinogen chains, which can affect the synthesis, assembly, intracellular processing, stability, or secretion of fibrinogen. In addition to standard coagulation tests depending on the formation of fibrin, diagnostics also includes global coagulation assays, which are effective in monitoring the management of replacement therapy. Genetic testing is a key point for confirming the clinical diagnosis. The identification of the precise genetic mutations of congenital fibrinogen disorders is of value to permit early testing of other at risk persons and better understand the correlation between clinical phenotype and genotype. Management of patients with afibrinogenemia is particularly challenging since there are no data from evidence-based medicine studies. Fibrinogen concentrate is used to treat bleeding, whereas for the treatment of thrombotic complications, administered low-molecular-weight heparin is most often. This review deals with updated information about afibrinogenemia and hypofibrinogenemia, contributing to the early diagnosis and effective treatment of these disorders.

The availability of direct oral anticoagulants has caused a paradigm shift in the management of thrombosis. Rivaroxaban and apixaban are 2 direct oral anticoagulants whose target specificity is activated factor X (FXa). However, it is still not fully understood if and how xabans impact platelet function. This observational study aimed to assess the in vitro platelet function in patients with atrial fibrillation receiving xabans. This was a single-center study quantifying platelet aggregation in 41 patients treated with apixaban or rivaroxaban by light transmission aggregometry. The thrombin receptor activating peptide (TRAP)-induced platelet aggregation was significantly lower 2 hours after taking rivaroxaban or apixaban compared to baseline value (56.15% [8.53%] vs 29.51% [12.9%]; P = .000). Moreover, concomitant use of angiotensin-converting enzyme blockers, proton pump inhibitors, and statins reduces the efficiency of xabans. The TRAP-induced platelet aggregation was reduced in patients with cardiovascular disease 2 hours after receiving xabans.

BACKGROUND Activated factor X (factor Xa) plays an important role in regulation of platelets. The aim of this study was to test the effect of direct oral factor Xa inhibitors-rivaroxaban and apixaban-on platelet aggregation in patients with nonvalvular atrial fibrillation. PATIENTS AND METHODS This single-center pilot study enrolled 21 factor Xa inhibitors-treated (9 rivaroxaban-treated and 12 apixaban-treated) patients with nonvalvular atrial fibrillation. The trough and peak samples of these patients were tested for adenosine diphosphate (ADP)-induced, epinephrine-induced, and collagen-induced platelet aggregation with light transmission aggregometry, and with factor Xa-calibrated anti-Xa chromogenic analysis. RESULTS The detected trough anti-Xa activity was 57.5 ± 43.4 μg/L. There was a significant increase in peak anti-Xa activity to 175.9 ± 119.6 μg/L (P < 0.001) observed. The platelet aggregation was reduced with reduced inductor concentration. However, no significant changes in ADP-induced, or in epinephrine-induced, or in collagen-induced platelet aggregation were seen comparing trough and peak sample. There were no significant differences in anti-Xa activity or in platelet aggregation comparing rivaroxaban-treated and apixaban-treated patients. CONCLUSIONS This study showed that factor Xa inhibition does not affect ADP-induced, epinephrine-induced, and collagen-induced platelet aggregation.

Dostickova hyperagregabilita, ako znama pricina trombozy, bola po prvýkrat popisana v 70. rokoch 20. storocia. Nazov SPS bol zavedený v 80. rokoch pre trombofilnu trombocytopatiu s familiarnym výskytom a autozomalnym typom dedicnosti, ktora bola charakterizovana hyperagregabilitou krvných dosticiek po nizkych koncentraciach adenozindifosfatu (ADP) a/alebo epinefrinu (EPI). V posledných 30 rokoch viaceri autori, ale najma E. F. Mammen a R. L. Bick, sa zaslužili o to, že boli vytvorene doposiaľ platne diagnosticke kriteria. Na zaklade výsledku agregometrie dosticiek po ADP a EPI existuju 3 podtypy SPS, ktore sa možu klinicky manifestovať viacerými typmi trombozy – a) arteriovou trombozou, vratane infarktu myokardu a ischemickej mozgovej prihody, b) venoznym tromboembolizmom a c) tehotenskými komplikaciami (strata plodu, intrauterinna rastova retardacia). O SPS sa spociatku predpokladalo, že ide o zriedkavu poruchu, ale neskor bol popisaný ako prekvapujuco casta pricina inak nevysvetliteľnej trombozy a tehotenských komplikacii. Napriek tomu, niektore kľucove problemy, ako je etiologia, genetika a epidemiologia SPS, zostali stale nejasne. Prva casť clanku podava prehľad o publikovaných výsledkoch výskumu SPS. Okrem zahranicných prac v nej uvadzame aj výsledky retrospektivnej studie nasho suboru pacientov s SPS (>450 symptomatických osob s SPS). V druhej casti sa venujeme sucasným problemom a výzvam pri SPS.

The authors describe a case of a rare infectious disease of intra-articular tissues of the temporomandibular joint caused mainly by Pseudomonas aeruginosa. In scientific literature, under the heading invasive (malignant) external otitis, we can find cases of an infectious disease of the external acoustic meatus caused by a microbial agent of Pseudomonas aeruginosa which can subsequently penetrate into structures. However, a primary affliction of the abovementioned structures has not been described. Localisation and severity of the infection requires long-term and massive treatment with antibiotics.

Background: The platelet function analyzer (PFA-100) is a system analyzing platelet function determined for detection of the functional inherited and acquired platelet disorders, screening of von Willebrand disease (vWD) and recently also considered as useful for monitoring of antiplatelet treatment. The PFA-100 test uses a high shear flow system to simulate in vitro the conditions to which platelets are subjected at the site of a damaged blood vessel wall. Aim of study: We decided to establish the reference intervals of PFA closure time (CT) in the Slovak population of healthy blood donors. Patients and methods: Fifty age and gender matched healthy blood donors were enrolled in the study. We investigated the relationships between PFA-100 CT, gender and ABO blood groups. Results: The reference intervals for CT measured on CEPI (collagen/epinephrine) and CADP (collagen/adenosine diphosphate) cartridge in 3.2% citrated blood were 86 - 199 sec. and 42 - 119 sec., respectively. Blood group O was associated with significantly longer CEPI CT (p Conclusion: PFA-100 CT should be interpreted carefully with consideration of both the patient’s clinical presentation and laboratory variables such as ABO blood group.

Background Proton pump inhibition (PPI) administrated together with adenosine diphosphate (ADP) receptor blockers (ADPRB) significantly reduces the risk of gastrointestinal bleeding. Nevertheless, there is a heated discussion about an interaction between PPI and ADPRB that leads to high on-treatment platelet reactivity (HTPR). Study question Is there a relationship between pantoprazole PPI and HTPR on ADPRB therapy in patients with acute ST-elevation myocardial infarction (STEMI). Methods Single center pilot study in patients with acute STEMI was performed. This study enrolled totally 87 patients (34 clopidogrel-treated and 53 new ADPRB-treated patients). Pantoprazole was administrated in 33 patients. HTPR was detected with ADP-induced light transmission aggregometry and vasodilator-stimulated phosphoprotein phosphorylation analysis. Samples were taken before coronary angiography (sample 1) and on the next day after the procedure (sample 2). Results No significant differences were found in pantoprazole-treated patients and patients without PPI neither in sample 1 (59.2 ± 29.5% vs. 54.9 ± 22.7%, P = 0.49) nor in sample 2 (43.8 ± 27.2% vs. 37.0 ± 22.9%, P = 0.30). Similarly, there were no significant differences in the platelet reactivity index of vasodilator-stimulated phosphoprotein phosphorylation in both samples (sample 1: 53.3 ± 29.8% vs. 65.0 ± 20.5%, P = 0.11; sample 2: 30.8 ± 27.1% vs. 40.6 ± 27.5%, P = 0.19). A comparison of clopidogrel and new ADP receptor blockers in patients on pantoprazole PPI did not reveal significant differences in on-treatment platelet reactivity. Conclusions This study did not reveal interaction between pantoprazole and ADPRB in patients with acute STEMI.

BACKGROUND Several studies demonstrated that proton pump inhibitors (PPIs) co-administrated with dabigatran in patients with atrial fibrillation (AF) decreased dabigatran trough and peak plasma levels. However, it is still unknown whether this interaction is reversible or not, and whether the withdrawal of PPI would lead to normalization of dabigatran plasma levels. AIM OF STUDY The aim of this study was to determine the effect of PPI withdrawal on dabigatran plasma levels in patients with AF. METHODS This pilot prospective study enrolled 23 AF patients on long-term dabigatran and PPI therapy (omeprazole 20 mg twice daily or pantoprazole 40 mg once daily). Dabigatran trough and peak levels (ng/mL) were tested on PPI and after a 2-week period of PPI withdrawal with Hemoclot Thrombin Inhibitor Assay. RESULTS The analysis of dabigatran plasma levels demonstrated significant elevation in trough dabigatran levels after 2 weeks of PPI withdrawal (97.2 ± 79.7 vs. 163.8 ± 105.5 ng/mL; P < 0.05). Moreover, significantly higher peak dabigatran levels were observed after 2 weeks of PPI withdrawal (142.4 ± 102.8 vs. 255 ± 129.5 ng/mL; P ≤ 0.001). CONCLUSIONS This study showed that a 2-week period of PPI withdrawal lead to a significant increase in dabigatran trough and peak plasma levels in patients with AF.