Thrombogenic Potential Research Articles

Oral Contraceptives and Venous Thromboembolism: Focus on Testing that May Enable Prediction and Assessment of the Risk

Combined oral contraceptives (COCs) induce several changes in the levels of coagulation factors. The levels of procoagulant factors are often increased, while levels of anticoagulant factors are decreased. Fibrinolysis is also affected, even if the effect seems to be more counterbalanced by opposite regulation of profibrinolytic and antifibrinolytic factors. These effects on hemostasis are more pronounced with third- or fourth-generation COC compared with second-generation COC. Venous thromboembolism (VTE) risk increases when multiple risk factors, including genetic and environmental, are present simultaneously. COC use causes changes in coagulation that modify the prothrombotic state induced by preexisting hemostatic alterations in a supra-additive manner. Therefore, testing appears to be of importance not only before implementing COC but also to monitor any potential thrombogenicity induced by COC therapy. Inherited genetic factors, such as factor V Leiden, G20210A prothrombin mutation, antithrombin, protein C or protein S deficiencies, non-O blood group, as well as CYP2C9*2 and the rs4379368 mutations, have all been identified as genetic predictive risk factors of VTE in women. Nevertheless, the screening of these genetic biomarkers is not capable of assessing the phenotypic expression of the risk. This review will focus on the different options for screening the thrombogenic status in this population. Specific attention will be given to the endogenous thrombin potential-based activated protein C resistance, a test aiming at assessing the thrombogenicity induced by hormonal therapies and inherited or acquired thrombophilia.

ANTITROMBOTIC ACTIVITY OF A NEW BENZIMIDAZOLE DERIVATIVE WITH A SPATIALLY DIFFICULT PHENOLIC SUBSTITUTE IN ITS STRUCTURE

The aimof the study was to investigate antithrombogenic properties of compound RU-1144 with previously identified pronounced antiplatelet and antioxidant activities. The thrombosis induced byFerric chloride(FeCl3) was carried out in rats’ carotid artery, in comparison with the known antiaggregant drugs - acetylsalicylic acid (ASA) and clopidogrel, as well as with the antioxidant preparation - ethylmethylhydroxypyridine succinate (EMHPS).Materials and methods.The antithrombotic activity of compound RU-1144 was studied on the model of the rats with carotid artery thrombosis, induced by the application of 50%ferric chloride(FeCl3), and the Global Thrombosis Test model (theGörög Thrombosis Test). The evaluation of this type of activity was carried out by prolonging the time of a blood clot formation. The studies of the compound RU-1144 effect on the bleeding time parameter were performed in mice. Acetylsalicylic acid, clopidogrel and EMHPS were used as reference drugs.Results.The antithrombotic effect of the RU-1144 substance revealed in the model of arterial thrombosis induced by the application offerric chloride(FeCl3), exceeded that of both acetylsalicylic acid and clopidogrel by 3.5 times and that of EMHPS by 2.9 times. In the modelof thein vitroGlobal Thrombosis Test (theGörög Thrombosis Test), compound RU-1144 reduced the thrombogenic potential of the blood equally with acetylsalicylic acid and clopidogrel. The assessment of “the bleeding time”, caused by the RU-1144 substance, showed that the prolongation of bleeding was twice as less pronounced than that caused by ASA and clopidogrel.Conclusion.The performed studies demonstrated a pronounced antithrombotic activity of compound RU-1144, which exceeded that of acetylsalicylic acid, clopidogrel and EMHPS, while the ability to prolong the bleeding time was reliably lower than that of reference drugs.Abbreviations:EMHPS-ethylmethylhydroxypyridine succinate; ASA - acetylsalicylic acid.

Platelet large cell ratio (P-LCR) in predicting acute coronary syndromes before aspirin use

Introduction: Platelet large cell ratio (P-LCR) test is one of the test parameters that is routinely calculated in the hemogram test, and expressed as the ratio of platelets with platelet volume greater than 12 fL. Large platelets are relatively younger and contain more intracellular granules, meaning that platelets have more thrombogenic potential. In the literature investigating the relationship between the acute coronary syndrome and P-LCR levels, the use of aspirin in patients and its effects on platelet parameters were ignored. In our study, for the first time in the literature, the relationship between P-LCR levels and acute coronary syndromes were investigated by means of including the patients before they took aspirin which ensures that P-LCR test is not affected by aspirin. Method: Retrospectively, patients aged 18-70 years were screened and those whose hemogram tests were completed before aspirin usage were included. A total of 109 patients diagnosed with unstable angina (UA), non-ST elevation myocardial infarction (NSTEMI) and ST-elevation myocardial infarction (STEMI) were included and compared in the study. Results: The mean P-LCR values were 23.61% (95% CI: 21.97-25.25) in UA patients, 28.34% (95% CI: 24.86-31.83) in NSTEMI, and 25.71% (95% CI: 22.07-29.35) in STEMI patients. There was a statistically significant difference between the P-LCR values among the groups (p=0.022). Conclusion: The increase in P-LCR, free of aspirin effects, was found to be statistically significant in acute coronary syndromes.

Venous Thromboembolism in COVID-19: Are Women Different?

AbstractThe epidemiological data suggests predominant male prevalence, morbidity and mortality with SARS COVID-2. Similarly, venous thromboembolic (VTE) events have a male sex predilection with variant mechanisms involving angiotensin-converting enzyme 2 (ACE-2) expression and pathways in women. COVID-19 could directly affect or it could be an indirect action of the disease via critical ailment hypoxemia, or hemostatic abnormalities might be the underlying mechanisms of VTE in a COVID-19 patient with baseline risk factor profile. VTE diagnosis in a COVID scenario has issues of a prone positioned patient, exposure of health workers and minimal therapeutic benefits in a critically ill patient with acute respiratory distress syndrome (ARDS). Anticoagulation with low-molecular weight heparin (LMWH) can be chosen over unfractionated heparin (UFH) with less monitoring requirements and thereby low exposure to healthcare workers. Variant guidelines for thromboprophylaxis (in hospital/extended postdischarge) have come up, stating anticoagulant administration, according to baseline risk profile and hemostatic biomarkers. Catheter-directed interventions should be reserved only for life-threatening situations. In women, hormonal milieu (for e.g., 17 β-estradiol) might influence occurrence of favorable ACE 2 polymorphisms with less VTE events. The management strategies in a female patient with VTE would be more or less similar to males. Combined oral contraceptives (COC) and estrogen replacement therapies (ERT) may be curtailed in COVID-19 positive patients, given their thrombogenic potential. Pregnancy and postpartum state in COVID-19 positive patient need VTE prophylaxis all the more in the presence of risk profile favoring VTE. Also, VTE prophylaxis when indicated should be continued in women in a normal menstrual cycle. Bleeding risks specific to women (menorrhagia secondary to dysfunctional uterine bleeding [DUB], fibroids, adnexal malignancies and masses, hypothyroidism, etc.) need to be weighed while taking a decision for indicated anticoagulation regimen.

Computed tomography angiography as an adjunct to computational fluid dynamics for prediction of oxygenator thrombus formation.

Extracorporeal membrane oxygenation circuit performance can be compromised by oxygenator thrombosis. Stagnant blood flow in the oxygenator can increase the risk of thrombus formation. To minimize thrombogenic potential, computational fluid dynamics is frequently applied for identification of stagnant flow conditions. We investigate the use of computed tomography angiography to identify flow patterns associated with thrombus formation. A computed tomography angiography was performed on a Quadrox D oxygenator, and video densitometric parameters associated with flow stagnation were measured from the acquired videos. Computational fluid dynamics analysis of the same oxygenator was performed to establish computational fluid dynamics-based flow characteristics. Forty-one Quadrox D oxygenators were sectioned following completion of clinical use. Section images were analyzed with software to determine oxygenator clot burden. Linear regression was used to correlate clot burden to computed tomography angiography and computational fluid dynamics-based flow characteristics. Clot burden from the explanted oxygenators demonstrated a well-defined pattern, with the largest clot burden at the corner opposite the blood inlet and outlet. The regression model predicted clot burden by region of interest as a function of time to first opacification on computed tomography angiography (R2 = 0.55). The explanted oxygenator clot burden map agreed well with the computed tomography angiography predicted clot burden map. The computational fluid dynamics parameter of residence time, when summed in the Z-direction, was partially predictive of clot burden (R2 = 0.35). In the studied oxygenator, clot burden follows a pattern consistent with clinical observations. Computed tomography angiography-based flow analysis provides a useful adjunct to computational fluid dynamics-based flow analysis in understanding oxygenator thrombus formation.

Lipoprotein(a) and Its Potential Association with Thrombosis and Inflammation in COVID-19: a Testable Hypothesis.

Purpose of ReviewThe COVID-19 pandemic has infected over > 11 million as of today people worldwide and is associated with significant cardiovascular manifestations, particularly in subjects with preexisting comorbidities and cardiovascular risk factors. Recently, a predisposition for arterial and venous thromboses has been reported in COVID-19 infection. We hypothesize that besides conventional risk factors, subjects with elevated lipoprotein(a) (Lp(a)) may have a particularly high risk of developing cardiovascular complications.Recent FindingsThe Lp(a) molecule has the propensity for inhibiting endogenous fibrinolysis through its apolipoprotein(a) component and for enhancing proinflammatory effects such as through its content of oxidized phospholipids. The LPA gene contains an interleukin-6 (IL-6) response element that may induce an acute phase–type increase in Lp(a) levels following a cytokine storm from COVID-19.SummaryThus, subjects with either baseline elevated Lp(a) or those who have an increase following COVID-19 infection, or both, may be at very high risk of developing thromboses. Elevated Lp(a) may also lead to acute destabilization of preexisting but quiescent atherosclerotic plaques, which might induce acute myocardial infarction and stroke. Ongoing studies with IL-6 antagonists may be informative in understanding this relationship, and registries are being initiated to measure Lp(a) in subjects infected with COVID-19. If indeed an association is suggestive of being causal, consideration can be given to systematic testing of Lp(a) and prophylactic systemic anticoagulation in infected inpatients. Therapeutic lipid apheresis and pharmacotherapy for the reduction of Lp(a) levels may minimize thrombogenic potential and proinflammatory effects. We propose studies to test the hypothesis that Lp(a) may contribute to cardiovascular complications of COVID-19.

Pulmonary embolism in COVID-19: Clinical characteristics and cardiac implications

BackgroundThe thrombogenic potential of Covid-19 is increasingly recognised. We aim to assess the characteristics of COVID-19 patients diagnosed with pulmonary embolism (PE). MethodsWe conducted a single centre, retrospective observational cohort study of COVID-19 patients admitted between 1st March and 30th April 2020 subsequently diagnosed with PE following computed tomography pulmonary angiogram (CTPA). Patient demographics, comorbidities, presenting complaints and inpatient investigations were recorded. ResultsWe identified 15 COVID-19 patients diagnosed with PE (median age = 58 years [IQR = 23], 87% male). 2 died (13%), both male patients >70 years. Most common symptoms were dyspnoea (N = 10, 67%) and fever (N = 7, 47%). 12 (80%) reported 7 days or more of non-resolving symptoms prior to admission. 7 (47%) required continuous positive airway pressure (CPAP), 2 (13%) of which were subsequently intubated. All patients had significantly raised D-dimer levels, lactate dehydrogenase (LDH), C-reactive protein (CRP), ferritin and prothrombin times. The distribution of PEs correlated with the pattern of consolidation observed on CTPA in 9 (60%) patients; the majority being peripheral or subsegmental (N = 14, 93%) and only 1 central PE. 10 (67%) had an abnormal resting electrocardiogram (ECG), the commonest finding being sinus tachycardia. 6 (40%) who underwent transthoracic echocardiography (TTE) had structurally and functionally normal right hearts. ConclusionOur study suggests that patients who demonstrate acute deterioration, a protracted course of illness with non-resolving symptoms, worsening dyspnoea, persistent oxygen requirements or significantly raised D-dimer levels should be investigated for PE, particularly in the context of COVID-19 infection. TTE and to a lesser degree the ECG are unreliable predictors of PE within this context.

Fluid dynamics characterization and thrombogenicity assessment of a levitating centrifugal pump with different impeller designs

Technical guidelines nowadays recommend and regulate the use Computational Fluid Dynamics (CFD) to assess the performance of medical devices. CFD coupled to blood damage models has emerged as a powerful tool to evaluate the hemocompatibility of blood recirculating devices. The present study is aimed at evaluating the hydrodynamic performance and the thrombogenic potential of two prototypes of magnetically levitating centrifugal pumps. The two devices differ in the impeller configuration - 6-blades vs. 12-blades – and have been designed to be used in Cardiopulmonary Bypass (CPB) circuits during open heart surgery and in Extracorporeal Membrane Oxygenation (ECMO) to support patients with severe cardiac or respiratory failure. The pumps have been modelled using Direct Numerical Simulation coupled to Lagrangian analysis to predict platelet activation due to abnormal shear stress histories. Numerical results have been compared with experimental data in terms of head generation for different working points. Results show that the 6-blades pump has i) smaller stagnation areas, ii) lower stress levels and iii) higher strain rate, resulting in a lower thrombogenic potential, whereas the 12-blade impeller guarantees a more stable performance at high flow rates, suggesting its preferential use for more demanding applications, such as CPB.

Incidence, Therapy, and Bleeding Risk-Cancer- Associated Thrombosis in Patients with Glioblastoma.

Cancer is an independent risk factor for the development of venous thromboembolism (VTE). Glioblastomas are amongst cancer types with the most thrombogenic potential and patients are at a particularly high risk of VTE with an incidence up to 20–30% per year. Currently, major efforts are underway to gain novel insights into risk factors and pathomechanisms to provide a better understanding of development of VTE in patients with primary brain tumors. Treatment of VTE requires therapeutic anticoagulation, which accordingly to recently-published guidelines should be performed using low molecular weight heparin or, in case of low bleeding risk, using a direct oral anticoagulant. However, this can be very challenging due to an increased risk of intracranial hemorrhage in this patient group. Furthermore, limited data are available on the subgroup of patients with primary brain tumors.

The Grafting of Multifunctional Antithrombogenic Chemical Networks on Polyurethane Intravascular Catheters.

Intravascular catheters (IVCs) and other medical tubing are commonly made of polymeric materials such as polyurethane (PU). Polymers tend to be fouled by surface absorption of proteins and platelets, often resulting in the development of bacterial infections and thrombosis during catheterization, which can lead to embolism and death. Existing solutions to fouling are based on coating the IVCs with hydrophilic, anti-thrombogenic, or antimicrobial materials. However, the delamination of the coatings themselves is associated with significant morbidity, as reported by the United States Food and Drug Administration (FDA). We developed a lubricious, antimicrobial, and antithrombogenic coating complex, which can be covalently attached to the surface of industrial PU catheters. The coating complex is pre-synthesized and comprises 2-methacryloyloxyethyl phosphorylcholine (MPC) as an antifouling agent, covalently attached to branched polyethyleneimine (bPEI) as a lubricating agent. The two-step coating procedure involves PU-amine surface activation using a diisocyanate, followed by chemical grafting of the bPEI-S-MPC complex. Compared with neat PU, the coating was found to reduce the coefficient of friction of the IVC surface by 30% and the hemolysis ratio by more than 50%. Moreover, the coating exhibited a significant antimicrobial activity under JIS Z2801:2000 standard compared with neat PU. Finally, in in-vivo acute rabbit model studies, the coating exhibited significant antithrombogenic properties, reducing the thrombogenic potential to a score of 1.3 on coated surfaces compared with 3.3 on uncoated surfaces. The materials and process developed could confer lubricious, antithrombogenic, and antimicrobial properties on pre-existing PU-based catheters.

Numerical evaluation of transcatheter aortic valve performance during heart beating and its post-deployment fluid-structure interaction analysis.

Transcatheter aortic valve replacement (TAVR) is a minimally invasive procedure that provides an effective alternative to open-heart surgical valve replacement for treating advanced calcific aortic valve disease patients. However, complications, such as valve durability, device migration, paravalvular leakage (PVL), and thrombogenicity may lead to increased overall post-TAVR morbidity and mortality. A series of numerical studies involving a self-expandable TAVR valve were performed to evaluate these complications. Structural studies were performed with finite element (FE) analysis, followed by computational fluid dynamics (CFD) simulations, and fluid-structure interaction (FSI) analysis. The FE analysis was utilized to study the effect of TAVR valve implantation depth on valve anchorage in the Living Heart Human Model, which is capable of simulating beating heart during repeated cardiac cycles. The TAVR deployment cases where no valve migration was observed were then used to calculate the post-deployment thrombogenic potential via CFD simulations. FSI analysis followed to further assess the post-deployment TAVR hemodynamic performance for different implantation depths. The deployed valves PVL, geometric and effective orifice areas, and the leaflets structural and flow stress magnitudes were compared to determine the device optimal landing zone. The combined structural and hemodynamic analysis indicated that with the TAVR valve deployed at an aft ventricle position an optimal performance was achieved in the specific anatomy studied. Given the TAVR's rapid expansion to younger lower-risk patients, the comprehensive numerical methodology proposed here can potentially be used as a predictive tool for both procedural planning and valve design optimization to minimize the reported complications.

An In Vitro Blood Flow Loop System for Evaluating the Thrombogenicity of Medical Devices and Biomaterials.

A reliable in vitro dynamic test method to evaluate device thrombogenicity is very important for the improvement of the design and safety of blood-contacting medical devices, while reducing the use of animal studies. In this study, a recirculating flow loop system was developed for thrombogenicity testing, using donor sheep blood anticoagulated with Anticoagulant Citrate Dextrose Solution A (ACDA) and used within 24-36 hr postdraw. Immediately before testing, the blood was recalcified and heparinized to a donor-specific target concentration. The heparinization level was based on a static pretest, in which latex tubes were incubated at room temperature for 30 min in blood with a series of heparin concentrations and evaluated for thrombus deposition. For dynamic testing, blood was recirculated at room temperature through a polyvinyl chloride (PVC) tubing loop containing a test material for 1 hr at 200 ml/min using a roller pump. Nine materials were investigated: a negative control (polytetrafluoroethylene [PTFE]), a positive control (latex), and seven commonly used biomaterials including PVC, two silicones with different formulations (Q-Sil and V-Sil), nylon, polyurethane (PU), high-density polyethylene (HDPE), and polyether block amide (PEBAX). The results showed that latex was significantly more thrombogenic than all the other materials (p < 0.05), PVC and Q-Sil exhibited intermediate thrombogenicity with significantly more thrombus surface coverage and thrombus weight than PTFE (p < 0.05), whereas PTFE and the rest of the biomaterials had little to no thrombus deposition. In summary, the test loop system was able to effectively differentiate materials with different thrombogenic potentials.

Evaluation of biomarkers for monitoring thrombogenic potential of FXaI16L.

: A zymogen-like activated factor X variant (FXa) is being developed for treating acute bleeding conditions. Activated factor V is an essential cofactor to FXa for activating prothrombin to thrombin. Thrombi/emboli formation was observed microscopically in FXa toxicity studies in animals. The objective of this research was to evaluate candidate biomarkers for FXa-induced thrombi/emboli formation to inform safety monitoring and dose-escalation decisions in FXa clinical trials. Effects of intravenous FXa administration on platelets, fibrinogen, activated partial thromboplastin time (aPTT), prothrombin time (PT), D-dimer, tissue factor pathway inhibitor, thrombin : antithrombin complex, antithrombin, and factor V, and protein C (PC) activities were evaluated in mice, rats, and monkeys. Mice had endogenous factor V activity 10× that of monkeys and were overly sensitive to FXa-induced thrombi/emboli formation. In monkeys, decreases in fibrinogen and prolongation in aPTT and PT emerged as potential biomarkers for impending FXa-induced thrombi/emboli formation, based on association of changes with microscopically observable thrombi/emboli (0-97 thrombi/emboli per monkey). PC decreases, measured by a clot-based assay, were also observed. A similar reduction in PC activity, when measured by clot-based assay, was observed in a phase 1 clinical trial. However, an in-vitro experiment with human plasma spiked with increasing concentrations of FXa indicated dose-dependent FXa-induced interference with clot-based assays and no depletion of PC or S by FXa in non-clot-based assays. Nonclinical biomarker studies identified fibrinogen, aPTT and PT as potential biomarkers for monitoring the clinical safety of FXa. Results of clot-based assays with FXa treatment should be interpreted with caution.

Тест генерации тромбина в оценке адаптационных возможностей системы гемокоагуляции у пациентов с дегенеративно-дистрофическими заболеваниями суставов

Введение. Поиски методов оценки функционального состояния системы гемокоагуляции у пациентов, которые ожидают выполнения эндопротезирования крупных суставов нижних конечностей, обоснованы высокой частотой встречаемости у них тромбоэмболических осложнений. Цель исследования: изучение теста генерации тромбина (ТГТ) с позиции оценки адаптационных возможностей системы гемокоагуляции у больных с дегенеративнодистрофическими заболеваниями крупных суставов нижних конечностей. Материалы и методы. Обследован 141 больной с дегенеративнодистрофическими поражениями тазобедренных и коленных суставов (35 мужчин, 106 женщин), средний возраст 62,6 9,9 лет. Контрольную группу составили 30 условно здоровых доноров, средний возраст 49,7 6,5 лет. Исследовали коагуляционные свой ства крови рутинными методами и регистрировали кривую процесса тромбинообразования в ТГТ, анализируя параметры: tlag латентное время тромбинообразования, ttpeak время достижения максимума тромбина, peak максимальное количество тромбина, VI индекс скорости тромбинообразования, AUC площадь под кривой. Больные были разделены на 2 группы в зависимости от характера изменения временных параметров ТГТ в ответ на инициацию тромбиногенеза активаторами с концентрацией тканевого фактора 2 пмоль/мл (активатор RB) и 5 пмоль/мл (активатор RClow). Результаты. В 1й группе значения параметров tlag и ttpeak в ответ на действие активатора RClow были меньше, чем на действие активатора RB, реакцию системы гемокоагуляции расценивали как адекватную. Во 2й группе значения tlag и ttpeak при использовании активатора RClow превышали величины аналогичных параметров при инициации тромбообразования активатором RB, а корреляционный анализ отразил ослабление связей между параметрами ТГТ, что свидетельствовало об адаптационной перестройке системы на фоне высокого тромбогенного потенциала и повышенном риске развития гемокоагуляционных осложнений у больных 2й группы. Заключение. ТГТ с использованием активаторов RB и RClow ерспективный инструмент выявления больных с высоким риском развития послеоперационных гемокоагуляционных осложнений. Introduction. The search of methods for assessing of hemocoagulation functional state in patients that are waiting endoprosthesis replacement of large joints of lower extremities is justified by the high incidence of thromboembolic complications. Aim: to study thrombin generation assay (TGA) for assessment of hemocoagulation adaptive potential in patients with degenerativedystrophic diseases of the large joints of lower extremities. Materials and methods. We examined 141 patients with degenerativedystrophic lesions of hip and knee joints (35 men, 106 women), average age was 62.6 9.9 years. Control group consisted of 30 relatively healthy donors, average age was 49.7 6.5 years. We investigated blood coagulation properties by routine methods and recorded the curve of thrombin formation by TGA. We analyzed next parameters: tlag is the latent time of thrombin formation, ttpeak is the time to reach the maximum of thrombin, peak is the maximum amount of thrombin, VI is the index of thrombin formation speed, AUC is the area under the curve. Patients were divided into 2 groups according TGA parameters in response to thrombinogenesis initiation by activators with different tissue factor concentrations 2 pmol/ml (RB activator) and 5 pmol/ml (RClow activator). Results. In the 1st group, tlag and ttpeak values in TGA with RClow activator were less than with RB activator, the hemocoagulation response was regarded as adequate. In the 2nd group, tlag and ttpeak values with RClow activator were higher than with RB activator and correlation analysis revealed the weakening of the relationships between TGA parameters. This indicated about system adaptation at a time of high thrombogenic potential and about increased risk of developing hemocoagulation complications in patients of the 2nd group. Conclusion. TGA with RB and RClow activators is a promising tool for identifying patients with a high risk of postoperative hemocoagulation complications.

Biomarkers of Hemostatic Dysregulation and Inflammation in Lymphoma: Potential Relevance to Thrombogenesis

INTRODUCTION: The prevalence of thrombotic complications in lymphoma patients ranges from 1.5% up to 59.5%. Lymphoma patients have a 10-fold higher risk for the development of venous thrombosis than patients with lung and gastrointestinal cancers. The pathogenesis of thromboembolic disease in hematological malignancies is complex and multifactorial and can be due to the underlying disorder or related to therapy. A number of biomarkers are associated with the occurence of VTE in cancer patients. Biomarkers reflect activation of coagulation and increased inflammatory potential. This study aimed to profile hemostatic and inflammatory biomarkers in patients with Hodgkin lymphoma, non-Hodgkin lymphoma, and chronic lymphocytic leukemia/ small lymphocytic lymphoma. METHODS: Citrated plasma samples were collected from lymphoma patients (n=96) under an IRB approved protocol Clinic for hematology, Lymphoma Center, University of Belgrade in Serbia. Samples were shipped to Loyola University Chicago and analyzed in batches via commercially available ELISA kits to profile biomarkers of coagulation activation and inflammation. Markers in Coagulation Activation: von Willebrand Factor (vWF), Factor XIIIa, Protein S, β2Glycoprotein I (β2GPI), D-dimer, Microparticles (MP), Urokinase-type Plasminogen Activator Antigen (uPA), Fibronectin. Markers of Inflammation included: Human Tumor Necrosis Factor- α (TNF- α), C-Reactive Protein (CRP), Plasminogen Activator Inhibitor Type 1 (PAI-1). The lymphoma patient population for each biomarker was compared to normal human pooled plasma (repeated 3 times for each biomarker), which consisted of 25 male and 25 females. RESULTS: The mean patients' age was 56 years (range, 19-80 years); 52.4% were males. Most patients were newly diagnosed and had advanced stage disease. A total of 42 patients (43.8%) had high-grade NHL; 17 (17.7%) had low-grade NHL; 24 (25.0%) had HLL; 7(7.3%) had HL; 6 (6.3%) had other forms. Lymphoma patients had significantly dysregulated following markers of coagulation: vWF, β2GPI, D-dimer, MP, uPA, and Fibronectin (Figure 1) (p&lt;0.001 for all in comparison to controls). TNF-α and CRP as markers of inflammation were also significantly increased in lymphoma patients (Figure 1) (p&lt;0.001 for both in comparison to controls). In lymphoma population 12 patients had thrombosis. Patients with thrombosis had significantly higher Factor XIIIa in comparison to lymphoma patients without thrombosis (106±9 vs. 85±256; p&lt;0.001). CONCLUSION: Hemostatic dysregulation and inflammation is present in lymphoma patients, which may reflect increased thrombogenic potential. Further studies are required to link clinical data and biomarker levels, with special emphasis on the involvement of FXIII in the development of thrombotic events in lymphoma patients. Biomarker profiling of lymphoma patients will also help in the understanding of the pathophysiologic mechanisms involved in the observed thrombotic complications and differentiating the sub-groups. Figure 1 Disclosures No relevant conflicts of interest to declare.

Platelet Function in Paroxysmal Nocturnal Haemoglobinuria

Introduction Paroxysmal nocturnal haemoglobinuria (PNH) is a rare acquired clonal haematopoietic stem cell disorder characterised by haemolytic anaemia, thrombosis and bone marrow failure. Thrombosis is considered a major cause for high morbidity and mortality in PNH patients (Hillmen P et al N Eng J Med 1995). However, the underlying mechanisms of thrombosis in PNH are still poorly understood. Various factors including defective interactions between the complement system, platelets and coagulation systems have been proposed (Peacock-Young B et al Haematologica 2017). Platelet function and clot formation in this disorder have not been comprehensively evaluated. Here we describe standard and novel techniques to evaluate platelet function in blood from PNH patients, to elucidate the underlying pro-thrombotic mechanisms. Methods Whole blood was collected from five PNH patients and compared to same-day healthy donor (HD) controls. The samples were collected at trough for those patients who were on eculizumab (Complement C5 inhibitor used in the treatment of PNH). Surface levels of platelet adhesion proteins and activation markers P-selectin and phosphatidylserine (PS) were assessed using flow cytometry. Plasma soluble GPVI (a platelet-specific activation marker) and cytokine levels were measured by ELISA. Clot formation was assessed by viscoelastic testing (ROTEM). Adhesion of platelets to collagen under flow in a whole blood assay was evaluated by Digital Holographic Microscopy (DHM) and thrombus height, surface area and volume quantified using custom-built MatLab-based software. Results Clinical characteristics of PNH patients were highly variable: two patients had history of thrombosis, three patients were on eculizumab, four patients were thrombocytopenic (&lt;150x109/L) and three were haemolysing. Platelet surface levels of adhesion/signalling receptor proteins including glycoproteins (GP) Iba, GPVI, aIIbb3, and ADAM10 (membrane expressed enzyme responsible for shedding GPVI from the surface) were all at lower ends of HD ranges. P-selectin and PS levels under resting and activated conditions and plasma soluble GPVI levels were comparable to same day HD. There were no differences between HD and PNH groups for levels of interleukin (IL) -6, IL-1β, tumour necrosis factor α, IL-17A, interferon γ or monocyte chemoattractant protein-1 (MCP-1). ROTEM analysis revealed slower formation of smaller clots in PNH patients, which correlated with their platelet count. Peak thrombus height and volume analysed by DHM were not different from data obtained with HD blood at both venous and arterial shear rates. However, both parameters were increased in PNH samples at arterial shearrate, when adjusted for platelet count (p&lt;0.01). Conclusion Analysis of these PNH patients with highly variable clinical characteristics did not identify a unifying platelet lesion. DHM could detect and quantify parameters of small thrombi in real time, in PNH patient samples and these data were consistent with enhanced thrombogenic potential in PNH patients. Mechanisms beyond platelet activation that contribute to increased thrombosis in these patients and the impact of eculizumab therapy on thrombotic propensity need to be explored further. Disclosures D'Rozario: Alexion: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Mechanical Circulatory Support: a Look Back and a Look Ahead

Heart failure is a growing problem across the world. Although many advances have been made in heart failure therapy, patients with cardiogenic shock still have a grim prognosis. The aim of this article is to discuss the current state of mechanical circulatory support and future directions. Mechanical support can be classified as temporary or durable. Temporary support ranges from the intra-aortic balloon pump to extracorporeal membrane oxygenation. Durable support consists of left ventricular assist devices that are long-term and can be used as a bridge to transplant or destination therapy. Many advances continue be made in terms of size, thrombogenic potential, and infection risk. As the supply of heart transplants is limited, mechanical support options for a growing heart failure population are becoming increasingly important. Deciding when to initiate and selecting the right device are of utmost importance and should be a multidisciplinary approach.

Pathophysiological role of prostanoids in coagulation of the portal venous system in liver cirrhosis.

BackgroundProstanoids are important regulators of platelet aggregation and thrombotic arterial diseases. Their involvement in the development of portal vein thrombosis, frequent in decompensated liver cirrhosis, is still not investigated.MethodsTherefore, we used pro-thrombotic venous milieu generation by bare metal stent transjugular intrahepatic portosystemic shunt insertion, to study the role of prostanoids in decompensated liver cirrhosis. Here, 89 patients receiving transjugular intrahepatic portosystemic shunt insertion were included in the study, and baseline levels of thromboxane B2, prostaglandin D2 and prostaglandin E2 were measured in the portal and the hepatic vein.ResultsWhile the hepatic vein contained higher levels of thromboxane B2 than the portal vein, levels of prostaglandin E2 and D2 were higher in the portal vein (all P<0.0001). Baseline concentrations of thromboxane B2 in the portal vein were independently associated with an increase of portal hepatic venous pressure gradient during short term follow-up, as an indirect sign of thrombogenic potential (multivariable P = 0.004). Moreover, severity of liver disease was inversely correlated with portal as well as hepatic vein levels of prostaglandin D2 and E2 (all P<0.0001).ConclusionsElevated portal venous thromboxane B2 concentrations are possibly associated with the extent of thrombogenic potential in patients with decompensated liver cirrhosis.Trial registrationClinicalTrials.gov identifier: NCT03584204.

Numerical simulation of blood fluid in hemodialysis catheters and its thrombogenic potential

The present study aimed to numerically simulate blood flow within central venous catheters of hemodialysis and its thrombogenic potential. Numerical simulation research performed through the dynamic computational program of fluids. A three-dimensional geometry of right and left internal jugular veins were built, taken from the Visible Human Project®. Catheters with obstructed and unobstructed lateral holes were constructed. For the simulation, we considered the duration of the cardiac cycle of 0.8 s with pulsatile cycle of 75 beats per minute. Shear stress, velocity and pressure increased when the catheter was within the vein and when they were obstructed. At the venous orifice of the catheter that was unobstructed, the velocity increased from 0.99 ± 0.02 m s-1 to 1.79 ± 0.009 m s-1 and the pressure from 1487 ± 0.8 Pa to 3215 ± 0.7 Pa. Blood re-circulation areas have created areas of stagnation of blood flow, making it more susceptible to the development of venous thrombi. This study may contribute to the expansion of multiprofessional partnerships between health professionals and Bioengineering fields in order to study health problems that can be verified through advanced technologies. Such technologies, such as simulation programs, detail possible adverse events based on scientific evidences which often occur silently in patients.

Effects of glycemic control and hypoglycemia on Thrombus formation assessed using automated microchip flow chamber system: an exploratory observational study

BackgroundThrombus formation is an important factor affecting cardiovascular events and venous thromboembolism in type 2 diabetes. However, it is unclear whether glycemic control reduces thrombogenicity. We investigated the effect of short-term glycemic control (STUDY 1) and hypoglycemia (STUDY 2) on thrombus formation using an automated microchip flow chamber system.MethodsFor STUDY 1, we recruited 10 patients with type 2 diabetes. Before and after 2 weeks of treatment, blood glucose was analyzed with a continuous glucose monitoring system, and thrombogenicity was analyzed with an automated microchip flow chamber system. For STUDY 2, we recruited 10 subjects without diabetes who underwent an insulin tolerance test. We evaluated the change in thrombogenic potential with hypoglycemia.ResultsSTUDY1: The mean blood glucose level reduced from 10.1 ± 2.6 to 6.9 ± 0.97 mM (P < 0.01). T10, an indicator of thrombogenicity, significantly attenuated after glycemic control (338 ± 65 vs. 425 ± 117 s, P < 0.05). The attenuation in T10 was significantly correlated with changes in mean blood glucose level after treatment (r = − 0.718, P < 0.05). STUDY 2: Platelet function was enhanced with decreasing blood glucose; increased platelet function was strongly correlated with an increase in epinephrine.ConclusionsWe demonstrated attenuation in thrombogenicity with short-term comprehensive diabetes care and enhancement in thrombogenicity with hypoglycemia, using a new flow chamber system.Trial registrationUMIN-CTR UMIN 000019899, registered 26-Jan-2015 (STUDY 2).