Total Thrombus-formation Analysis System Research Articles

Effect of Oxidative Stress on Mitochondrial Damage and Repair in Heart Disease and Ischemic Events.

The literature analysis conducted in this review discusses the latest achievements in the identification of cardiovascular damage induced by oxidative stress with secondary platelet mitochondrial dysfunction. Damage to the platelets of mitochondria as a result of their interactions with reactive oxygen species (ROS) and reactive nitrogen species (RNS) can lead to their numerous ischemic events associated with hypoxia or hyperoxia processes in the cell. Disturbances in redox reactions in the platelet mitochondrial membrane lead to the direct oxidation of cellular macromolecules, including nucleic acids (DNA base oxidation), membrane lipids (lipid peroxidation process) and cellular proteins (formation of reducing groups in repair proteins and amino acid peroxides). Oxidative changes in biomolecules inducing tissue damage leads to inflammation, initiating pathogenic processes associated with faster cell aging or their apoptosis. The consequence of damage to platelet mitochondria and their excessive activation is the induction of cardiovascular and neurodegenerative diseases (Parkinson's and Alzheimer's), as well as carbohydrate metabolism disorders (diabetes). The oxidation of mitochondrial DNA can lead to modifications in its bases, inducing the formation of exocyclic adducts of the ethano and propano type. As a consequence, it disrupts DNA repair processes and conduces to premature neoplastic transformation in critical genes such as the p53 suppressor gene, which leads to the development of various types of tumors. The topic of new innovative methods and techniques for the analysis of oxidative stress in platelet mitochondria based on methods such as a nicking assay, oxygen consumption assay, Total Thrombus formation Analysis System (T-Tas), and continuous-flow left ventricular assist devices (CF-LVADs) was also discussed. They were put together into one scientific and research platform. This will enable the facilitation of faster diagnostics and the identification of platelet mitochondrial damage by clinicians and scientists in order to implement adequate therapeutic procedures and minimize the risk of the induction of cardiovascular diseases, including ischemic events correlated with them. A quantitative analysis of the processes of thrombus formation in cardiovascular diseases will provide an opportunity to select specific anticoagulant and thrombolytic drugs under conditions of preserved hemostasis.

Abstract 4134384: Sotagliflozin, a Dual Inhibitor of Sodium-Glucose Transporters 1 and 2, Elicits Cardioprotective Effects Through Attenuation of Platelet Activation and Thrombosis

Sodium-glucose cotransporter (SGLT) inhibitors are used in the treatment of type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD). In the SCORED trial, sotagliflozin (SOTA), a dual SGLT1/2 inhibitor, demonstrated significant reductions in both myocardial infarction (MI) and stroke in patients with T2DM and CKD. These results suggest a cardiovascular (CV) benefit of SOTA in patients with T2DM and CKD who are at increased risk of thromboembolic disease. To investigate the underlying mechanism of CV protection, we evaluated the effects of SOTA on platelet activation and thrombus formation, in both in vivo and ex vivo models, to understand its effects on MI and stroke. Washed human platelets treated with SOTA were stimulated with various agonists and platelet activation was assessed via lumi-aggregometry and flow cytometry. In whole blood, SOTA was evaluated for its potential to reduce platelet adhesion and thrombus formation in the perfusion flow chamber and Total Thrombus formation Analysis System (TTAS) assays. In vivo , mice dosed with SOTA were assessed for thrombus formation at the site of injury in real-time in the cremaster arteriole injury model. To determine the effect of SOTA on hemostasis, we assessed coagulation parameters ex vivo in human whole blood using thromboelastography. Finally, bleeding time was measured in vivo in mice dosed with SOTA using the tail bleeding assay. In washed platelets, SOTA inhibits platelet activation and aggregation in a dose-dependent manner. Similarly, a dose-dependent decrease in platelet adhesion and thrombus formation was observed in whole blood assays. In vivo , platelet accumulation and fibrin formation were decreased in mice dosed with SOTA, however no effect is observed in coagulation parameters or bleeding time. SOTA inhibits platelet activation and thrombus formation with no impact on coagulation parameters or bleeding potential. These findings highlight a potential mechanism through which SOTA reduces the risk of stroke and MI in patients with T2DM and CKD, underscoring the importance of further investigation into the role of SOTA in CV protection, particularly in patients suffering from both T2DM and CKD at high risk of thromboembolic events.

Evaluation of platelet function by Total Thrombus-Formation Analysis System (T-TAS®01) in term and preterm infants and its relationship with patent ductus arteriosus. A prospective observational pilot study.

Newborns exhibit a pro-coagulant hemostatic profile despite platelet hyporeactivity and reduced coagulation factors. Assessing infant hemostasis, particularly in preterm infants, is challenging, with inconsistent findings regarding the relationship between platelet count and function in patients with patent ductus arteriosus (PDA). This study aims to assess platelet function using the Total Thrombus-Formation Analysis System (T-TAS®01) in term and preterm newborns. T-TAS®01 measures the Occlusion Start Time (OST), Occlusion Time (OT), and the Area Under the Curve (AUC) at the end of thrombus formation. The study includes term and preterm newborns below 30 weeks' gestational age (GA) admitted to the Neonatal Intensive Care Unit. Blood samples were collected from preterm newborns on the 1st day of life (T0), between 48-72 hours of life (T1), between the 7th and 10th day of life (T2), and from term newborns at T0 and T2. Secondary endpoints include the relationship between T-TAS®01 parameters and significant PDA in preterm newborns and the correlation between T-TAS®01 parameters, GA, and complete blood count (CBC). OST is delayed by 65.5 seconds in preterm infants at T0 (p<0.001) and by 46 seconds at T2 (p=0.041) compared to full-term newborns. OT is delayed by 164 seconds in preterm infants at T0 (p=0.002) and by 352 seconds at T2 (p=0.002). AUC at T0 is lower in preterm infants (p=0.028). There is no significant correlation between T-TAS®01 parameters and GA or CBC. Additionally, OST and OT are delayed, and AUC is reduced in preterm infants with PDA and hemodynamically significant PDA (hsPDA). T-TAS®01 is a reliable tool for evaluating platelet function in term newborns. However, measurements show higher variability in preterm infants, with significantly lower platelet activity observed in preterm infants with PDA and hsPDA.

Impaired arterial dilation and increased NOX2 generated oxidative stress in subjects with ataxia-telangiectasia mutated (ATM) kinase

BackgroundSubjects with mutations in the Ataxia-Telangiectasia mutated (ATM) gene encoding for ATM kinase have a greater predisposition to develop atherosclerosis, but the mechanism behind this phenomenon is not yet understood. NADPH oxidase type 2 may play a role in this process, leading to endothelial dysfunction and an increased susceptibility to thrombosis. The purpose of this study was to assess the redox state in individuals with ATM mutations and determine its impact on endothelial function. MethodsIn this cross-sectional study, twenty-seven children with ataxia telangiectasia (AT) (13 males and 14 females, mean age 15.1 ± 7.6 years) were compared with 27 controls (13 males and 14 females, mean age 14.6 ± 8.4 years) matched for age and gender. Additionally, 29 AT parents with heterozygous mutation of ATM (h-ATM) gene, and 29 age- and gender-matched controls were included. Endothelial function was evaluated through brachial flow-mediated dilation (FMD) and the assessment of nitric oxide (NO) bioavailability. Oxidative stress was evaluated by measuring serum activity of soluble NOX2-dp (sNOX2-dp), hydrogen peroxide (H2O2) production, and hydrogen breakdown activity (HBA). Thrombus formation was assessed through the Total Thrombus Formation Analysis System (T-TAS). ResultsAT children and parents with heterozygous ATM mutations exhibited significantly lower FMD, HBA, and NO bioavailability as compared to age and gender matched controls. AT children and ATM carrier of heterozygous ATM mutations had significantly higher concentrations of sNOX2-dp and H2O2 as compared to controls. Compared to the respective controls, AT children and their parents, who carried heterozygous ATM mutation, showed an accelerated thrombus growth as revealed by reduced occlusion time. Multivariable linear regression analysis revealed that sNOX2 (standardized coefficient β: −0.296; SE: 0.044; p = 0.002) and NO bioavailability (standardized coefficient β: 0.224; SE: 0.065; p = 0.02) emerged as the only independent predictive variables associated with FMD (R2: 0.44). ConclusionsThis study demonstrates that individuals with ATM mutations experience endothelial dysfunction, increased oxidative stress, and elevated thrombus formation. These factors collectively contribute to the heightened susceptibility of these individuals to develop atherosclerosis.

Elevated Leukocyte Count and Platelet-Derived Thrombogenicity Measured Using the Total Thrombus-Formation Analysis System in Patients with ST-Segment Elevation Myocardial Infarction.

High platelet-derived thrombogenicity during the acute phase of ST-segment elevation myocardial infarction (STEMI) is associated with poor outcomes; however, the associated factors remain unclear. This study aimed to examine whether acute inflammatory response after STEMI affects platelet-derived thrombogenicity. This retrospective observational single-center study included 150 patients with STEMI who were assessed for platelet-derived thrombogenicity during the acute phase. Platelet-derived thrombogenicity was assessed using the area under the flow-pressure curve for platelet chip (PL-AUC), which was measured using the total thrombus-formation analysis system (T-TAS). The peak leukocyte count was evaluated as an acute inflammatory response after STEMI. The patients were divided into two groups: the highest quartile of the peak leukocyte count and the other three quartiles combined. Patients with a high peak leukocyte count (＞15,222/mm3; n=37) had a higher PL-AUC upon admission (420 [386-457] vs. 385 [292-428], p=0.0018), higher PL-AUC during primary percutaneous coronary intervention (PPCI) (155 [76-229] vs. 96 [29-170], p=0.0065), a higher peak creatine kinase level (4200±2486 vs. 2373±1997, p＜0.0001), and higher PL-AUC 2 weeks after STEMI (119 [61-197] vs. 88 [46-122], p=0.048) than those with a low peak leukocyte count (≤ 15,222/mm3; n=113). The peak leukocyte count after STEMI positively correlated with PL-AUC during primary PPCI (r=0.37, p＜0.0001). A multivariable regression analysis showed the peak leukocyte count to be an independent factor for PL-AUC during PPCI (β=0.26, p=0.0065). An elevated leukocyte count is associated with high T-TAS-based platelet-derived thrombogenicity during the acute phase of STEMI.

Antiplatelet effects of hydroxychloroquine in patients with systemic lupus erythematosus evaluated by the total thrombus-formation analysis system (T-TAS)

ObjectivesHydroxychloroquine (HCQ) has been shown to reduce thrombotic events in patients with SLE. However, the antiplatelet effects of HCQ are only supported by the platelet aggregation assay, which is a...

Subclinical leaflet thrombus in patients with severe aortic stenosis and atrial fibrillation -ENRICH-AF TAVI study

Subclinical leaflet thrombosis (SLT) can be one of the causes of transcatheter heart valve (THV) failure after transcatheter aortic valve implantation (TAVI). We sought to clarify the formation process of SLT and thrombogenicity during the perioperative period of TAVI. This multicenter, prospective, single-arm interventional study enrolled 26 patients treated with edoxaban for atrial fibrillation and who underwent TAVI for severe aortic stenosis between September 2018 and September 2022. We investigated changes in maximal leaflet thickness detected by contrast-enhanced computed tomography between 1 week and 3 months after TAVI in 18 patients and measured the thrombogenicity by Total Thrombus-formation Analysis System (T-TAS) and flow stagnation volume by computational fluid dynamics (CFD) (n = 11). SLT was observed in 16.7% (3/18) at 1 week, but decreased to 5.9% (1/17) at 3 months after TAVI. Patients with SLT at 1 week had a significantly decreased maximal leaflet thickness compared to those without SLT. Thrombogenicity assessed by T-TAS decreased markedly at 1 week and tended to increase at 3 months. The stagnation volume assessed by CFD was positively associated with a higher maximum leaflet thickness. This study showed the course of leaflet thrombus formation and visualization of stagnation in neo-sinus of THV in the acute phase after TAVI.

New Findings Regarding the Effects of Selected Blue Food Colorants (Genipin, Patent Blue V, and Brilliant Blue FCF) on the Hemostatic Properties of Blood Components In Vitro.

Natural and synthetic colorants present in food can modulate hemostasis, which includes the coagulation process and blood platelet activation. Some colorants have cardioprotective activity as well. However, the effect of genipin (a natural blue colorant) and synthetic blue colorants (including patent blue V and brilliant blue FCF) on hemostasis is not clear. In this study, we aimed to investigate the effects of three blue colorants-genipin, patent blue V, and brilliant blue FCF-on selected parameters of hemostasis in vitro. The anti- or pro-coagulant potential was assessed in human plasma by measuring the following coagulation times: thrombin time (TT), prothrombin time (PT), and activated partial thromboplastin time (APTT). Moreover, we used the Total Thrombus formation Analysis System (T-TAS, PL-chip) to evaluate the anti-platelet potential of the colorants in whole blood. We also measured their effect on the adhesion of washed blood platelets to fibrinogen and collagen. Lastly, the cytotoxicity of the colorants against blood platelets was assessed based on the activity of extracellular lactate dehydrogenase (LDH). We observed that genipin (at all concentrations (1-200 µM)) did not have a significant effect on the coagulation times (PT, APTT, and TT). However, genipin at the highest concentration (200 µM) and patent blue V at the concentrations of 1 and 10 µM significantly prolonged the time of occlusion measured using the T-TAS, which demonstrated their anti-platelet activity. We also observed that genipin decreased the adhesion of platelets to fibrinogen and collagen. Only patent blue V and brilliant blue FCF significantly shortened the APTT (at the concentration of 10 µM) and TT (at concentrations of 1 and 10 µM), demonstrating pro-coagulant activity. These synthetic blue colorants also modulated the process of human blood platelet adhesion, stimulating the adhesion to fibrinogen and inhibiting the adhesion to collagen. The results demonstrate that genipin is not toxic. In addition, because of its ability to reduce blood platelet activation, genipin holds promise as a novel and valuable agent that improves the health of the cardiovascular system and reduces the risk of cardiovascular diseases. However, the mechanism of its anti-platelet activity remains unclear and requires further studies. Its in vivo activity and interaction with various anti-coagulant and anti-thrombotic drugs, including aspirin and its derivatives, should be examined as well.

A novel haemodilution chip mounted on the total thrombus-formation analysis system, a flow chamber system, enables stable analysis of platelet products under low platelet concentration/high shear conditions.

The total thrombus-formation analysis system (T-TAS) can quantitatively analyse the contribution of platelets to haemostasis using reconstituted blood samples. However, it is unsuitable in cases with low platelet counts. We introduced a haemodilution (HD) chip with a shallow chamber depth, adapted to low platelet counts and high shear conditions (1500 s-1). Blood samples were prepared by mixing red blood cell products, standard human plasma and platelet products; the final platelet count was 50 × 103/μL. Aggregation tests were performed by using the aggregation inducers collagen, adenosine diphosphate (ADP) and ristocetin. Samples with 2-, 4- and 9-day-old platelet products (N = 10) were evaluated. The HD chip enabled the stable analysis of the haemostatic function of all samples at a platelet count of 50 × 103/μL. Haemostatic function was correlated with ADP aggregation (time to 10 kPa [T10]: r = -0.53; area under the curve for 30 min: r = 0.40) and storage period (T10: r = 0.44). The HD chip-mounted T-TAS can stably analyse haemostatic function under low platelet counts and high shear conditions; this approach is expected to serve as a bridge to in vivo haemostatic tests with experimental animals.

Factors that modulate platelet reactivity as measured by 5 assay platforms in 3429 individuals

BackgroundAssessment of platelet function is key in diagnosing bleeding disorders and evaluating antiplatelet drug efficacy. However, there is a prevailing “one-size-fits-all” approach in the interpretation of measures of platelet reactivity, with arbitrary cutoffs often derived from healthy volunteer responses. ObjectivesOur aim was to compare well-used platelet reactivity assays. MethodsBlood and platelet-rich plasma obtained from the Framingham Heart Study (N = 3429) were assayed using a range of agonists in 5 platelet assays: light transmission aggregometry, Optimul aggregometry, Multiplate impedance aggregometry (Roche Diagnostics), Total Thrombus-Formation Analysis System, and flow cytometry. Using linear mixed-effect models, we determined the contribution of preanalytical and technical factors that modulated platelet reactivity traits. ResultsA strong intra-assay correlation of platelet traits was seen in all assays, particularly Multiplate velocity (r = 0.740; ristocetin vs arachidonic acid). In contrast, only moderate interassay correlations were observed (r = 0.375; adenosine diphosphate Optimul Emax vs light transmission aggregometry large area under the curve). As expected, antiplatelet drugs strongly reduced platelet responses, with aspirin use primarily targeting arachidonic acid–induced aggregation, and explained substantial variance (β = −1.735; P = 4.59 × 10−780; variance proportion = 46.2%) and P2Y12 antagonists blocking adenosine diphosphate responses (β = −1.612; P = 6.75 × 10−27; variance proportion = 2.1%). Notably, female sex and older age were associated with enhanced platelet reactivity. Fasting status and deviations from standard venipuncture practices did not alter platelet reactivity significantly. Finally, the agonist batch, phlebotomist, and assay technician (more so for assays that require additional sample manipulation) had a moderate to large effect on measured platelet reactivity. ConclusionCaution must be exercised when extrapolating findings between assays, and the use of standard ranges must be medication-specific and sex-specific at a minimum. Researchers should also consider preanalytical and technical variables when designing experiments and interpreting platelet reactivity measures.

T-TAS® 01 as a new tool for the evaluation of hemostasis in thrombocytopenic patients after platelet transfusion.

Current laboratory tests fail to evaluate the hemostatic function of platelets in patients with thrombocytopenia. We investigated the use of the Total Thrombus-Formation Analysis System (T-TAS® 01 [Fujimori Kogyo Co, Tokyo, Japan]) to evaluate hemostasis under conditions of experimental thrombocytopenia, and in patients before and after platelet transfusion. Specific T-TAS 01 chips, for thrombocytopenic conditions, were used. The area under the curve (AUC) and occlusion time (OT, min) were measured in: (i) experimentally induced thrombocytopenia (183±15 to 6.3±1.2×103 platelets/μL) in blood samples from healthy donors (No.=13), and (ii) blood from oncohematological thrombocytopenic patients (No.=48), before and after platelet transfusion. The influences of hematocrit and number of transfusions were analyzed in these patients. Progressive reductions of AUC and prolongations of OT related significantly to decreasing platelet counts (p<0.05 for all) in experimental thrombocytopenia. In samples from thrombocytopenic patients, platelet counts, AUC and OT were, respectively, 10.8±0.6×103/μL, 175.2±59, and 27.2±1 min before transfusion; and 22±1.5×103/μL, 400.8±83 and 22.9±1.5 min after platelet transfusion (p<0.01 for all). A hematocrit below 25% or exposure to ten or more previous platelet transfusions had a negative impact on the T-TAS 01 performance in patients. In vitro correction of the hematocrit improved the hemostatic response in thrombocytopenic patients. T-TAS 01 measurements were sensitive to low platelet counts in the experimental setting. The technology was sensitive to evaluate the hemostatic capacity of platelet transfusions. Exposure to multiple medications, repeated platelet transfusions and lower hematocrits may interfere with the hemostatic performance in oncohematological patients with thrombocytopenia.

Total Thrombus-Formation System in Patients with Peripheral Artery Disease.

The Total Thrombus-formation Analysis System (T-TAS) is an automated device using coated microchips to assess thrombus formation under flow conditions. Its value to monitor coagulation function in patients under antiplatelet therapy awaits further clarification. This study evaluated T-TAS to detect response to dual antiplatelet therapy (DAPT) in patients with peripheral artery disease (PAD).T-TAS using the platelet-chip (PL-chip) and atheroma-chip (AR-chip) was performed in 60 patients with PAD on the day after lower extremity revascularization. Results were compared with light transmission aggregometry (LTA) and multiple electrode aggregometry (MEA, ADP- and ASPI-test). To determine T-TAS reference ranges, 30 healthy blood donors were enrolled.The area under the curve of the PL-chip (AUC-PL) was outside the reference range in 91.2% and AUC-AR in 21.1% of the PAD patients. Low responders in MEA ASPI, MEA ADP or both tests and low responders in LTA induced by ADP had a significantly higher AUC-PL compared to responders (204 vs 70, p = .016 and 140 vs 32, p < .001), respectively. Median AUC-PL in low responders in LTA and MEA, LTA or MEA and in responders in LTA and MEA was 301, 104 and 32 (p = .001), respectively. Our results suggest that the PL-chip can continuously assess the level of response to DAPT and might be helpful to monitor PAD patients.

BNP level predicts bleeding event in patients with heart failure after percutaneous coronary intervention

ObjectiveThis study aimed to investigate the association between heart failure (HF) severity measured based on brain natriuretic peptide (BNP) levels and future bleeding events after percutaneous coronary intervention (PCI).BackgroundThe Academic...

Pharmacodynamic and pharmacokinetic profiles associated with switching from cangrelor to prasugrel in patients undergoing percutaneous coronary intervention: the SWAP-6 study

Abstract Background Cangrelor is an intravenous P2Y12 inhibitor used in patients undergoing coronary intervention (PCI). Preliminary studies have shown the potential for a drug-drug interaction (DDI) when transitioning from cangrelor to oral P2Y12 inhibition with prasugrel. However, to date this has not been prospectively tested in patients undergoing PCI. Purpose To rule out a DDI when cangrelor and prasugrel are concomitantly administered in patients undergoing PCI. Methods SWAP-6 is a prospective, randomized, 3-arm, open-label, pharmacokinetic (PK) and pharmacodynamic (PD) study conducted in patients undergoing PCI (n=77). Patients were randomized to either a) prasugrel only administered at the start of PCI; b) cangrelor plus prasugrel concomitantly administered at the start of PCI; c) cangrelor administered at the start of PCI plus prasugrel administered at the end of the cangrelor infusion. Cangrelor (30 μg/kg bolus followed by 4 μg/kg/min infusion) was maintained for 2 hours and all patients were on a background of aspirin therapy. Prasugrel was administered as a 60 mg loading dose. PK analysis included plasma levels of prasugrel active metabolite, and PD assessments included VerifyNow PRU, total thrombus-formation analysis system (T-TAS), and vasodilator-stimulated phosphoprotein (VASP), at baseline and 6 time points after prasugrel/cangrelor administration. The primary end point was non-inferiority in PRU measured at 4 hours after prasugrel/cangrelor loading (2 hours after stopping cangrelor infusion) of cangrelor plus prasugrel concomitantly administered versus prasugrel only. The noninferiority margin was defined as 45 PRU. Results Cangrelor achieved lower PRU levels than prasugrel only as early as 30 minutes and up to 2 hours after bolus administration (Figure). At 3 hours after prasugrel/cangrelor loading, PRU levels were higher with cangrelor compared to prasugrel only. At 4 hours after loading (2 hours after stopping cangrelor infusion), PRU levels were significantly lower with prasugrel only compared to cangrelor and prasugrel concomitantly administered (LSM difference 130; 95% CI: 85-176), failing to meet the prespecified noninferiority primary end point (Figure). At this time point, cangrelor followed by prasugrel at the end of the infusion had higher PRU than prasugrel only, but lower than cangrelor and prasugrel concomitantly. Platelet reactivity by T-TAS and VASP showed consistent findings. PK analysis tracked PD results (data not shown). Conclusions In patients undergoing PCI, cangrelor is associated with more potent platelet inhibition than prasugrel alone. However, concomitant administration of prasugrel with cangrelor leads to a marked increase in platelet reactivity after stopping cangrelor infusion, supporting the presence of a DDI. This underscores the importance of administering prasugrel not until the end of cangrelor infusion, a strategy which mitigates the increase in platelet reactivity.

Abstract 12293: Subclinical Leaflet Thrombus on Transcatheter Heart Valve in Patients With Severe Aortic Stenosis and Atrial Fibrillation

Background: Subclinical leaflet thrombosis is one of transcatheter heart valve (THV) failure that should be avoided after transcatheter aortic valve implantation (TAVI). Although the effectiveness of direct oral anticoagulants (DOACs) on subclinical leaflet thrombosis has been demonstrated, there is insufficiently established evidence for post-TAVI antithrombotic therapy. The aim of this study was to clarify the formation process of subclinical leaflet thrombosis on THV and thrombogenicity during the perioperative period of TAVI. Methods: This multicenter, prospective, single-arm interventional study enrolled 26 patients with atrial fibrillation treated with edoxaban and severe aortic valve stenosis who underwent TAVI between September 2018 and September 2022. After exclusion, 24 patients were finally analyzed. We investigated changes in maximal leaflet thickness detected by contrast-enhanced computed tomography between 1 week and 3 months after TAVI and measured the thrombogenicity by Total Thrombus-formation Analysis System (T-TAS) and flow stagnation volume by computational fluid dynamics (CFD). Results: Of all, subclinical leaflet thrombosis was observed in 16.7% at 1 week, but decreased to 5.9% at 3 months after TAVI. There was no significant difference in maximum leaflet thickness between 1 week and 3 months, however, patients with subclinical leaflet thrombosis at 1 week had a significantly greater difference in that thickness compared to those without thrombosis. Thrombogenicity assessed by T-TAS and platelet count decreased markedly at 1 week and tended to improve at 3 months. Simple liner regression analysis showed that stagnation volume was positively associated with an increase in maximum leaflet thickness, and low-dose edoxaban was associated with a high risk of increased leaflet thickness at chronic phase. Conclusions: This study showed that course of leaflet thrombus formation in neo-sinus of THV and dynamic fluctuation of thrombogenicity in the acute phase after TAVI. These findings were merely hypotheses generation and thus necessitate future hypothesis testing with large sample sizes.

PB0132 Hemostatic Evaluation of Patients with Thrombocytopenia Receiving Platelet Transfusion using the Total Thrombus Formation Analysis System (T-TAS)

PB0132 Hemostatic Evaluation of Patients with Thrombocytopenia Receiving Platelet Transfusion using the Total Thrombus Formation Analysis System (T-TAS)

The oxylipin analog CS585 prevents platelet activation and thrombosis through activation of the prostacyclin receptor

AbstractCardiovascular disease remains the primary cause of morbidity and mortality globally. Platelet activation is critical for maintaining hemostasis and preventing the leakage of blood cells from the vessel. There has been a paucity in the development of new drugs to target platelet reactivity. Recently, the oxylipin 12(S)-hydroxy-eicosatrienoic acid (12-HETrE), which is produced in platelets, was shown to limit platelet reactivity by activating the prostacyclin receptor. Here, we demonstrated the synthesis of a novel analog of 12-HETrE, known as CS585. Human blood and mouse models of hemostasis and thrombosis were assessed for the ability of CS585 to attenuate platelet activation and thrombosis without increasing the risk of bleeding. Human platelet activation was assessed using aggregometry, flow cytometry, western blot analysis, total thrombus formation analysis system, microfluidic perfusion chamber, and thromboelastography. Hemostasis, thrombosis, and bleeding assays were performed in mice. CS585 was shown to potently target the prostacyclin receptor on the human platelet, resulting in a highly selective and effective mechanism for the prevention of platelet activation. Furthermore, CS585 was shown to inhibit platelet function in human whole blood ex vivo, prevent thrombosis in both small and large vessels in mouse models, and exhibit long-lasting prevention of clot formation. Finally, CS585 was not observed to perturb coagulation or increase the risk of bleeding in the mouse model. Hence, CS585 represents a new validated target for the treatment of thrombotic diseases without the risk of bleeding or off-target activation observed with other prostaglandin receptor agonists.

Hemostatic disorders in patients with infective endocarditis undergoing urgent surgical valve replacement – Rethinking current beliefs

BackgroundAlthough infective endocarditis (IE) represents a unique model of thrombo-inflammatory disease, the most frequent early complications of surgical valve replacement (SVR) in IE population are coagulopathy and bleeding. The hemostatic capacity and procedure-related coagulation disorders of IE patients undergoing SVR are unknown. The aims of this study were to test periprocedural hemostasis in IE patients undergoing urgent SVR, and to assess the association between disorders of hemostasis and early bleeding as well as with thromboembolic events. MethodsA prospective, two-center, hypothesis generating, observational study was performed between Dec 2017 and Jan 2020. Periprocedural hemostasis of IE patients was assessed using Total Thrombus-formation Analysis System (T-TAS Plus) within 24 h before and 72 h post SVR. ResultsOverall, 25 patients with active IE undergoing urgent SVR were tested. Hemostatic capacity of IE patients was significantly impaired pre-SVR as well as post-SVR compared to normal values, in most aspects of T-TAS assays under high and low shear forces, including prolonged activation of coagulation (T10), final clot formation (OT) and clot strength (AUC30). Post-SVR T-TAS results were significantly associated with early bleeding and with red blood cell, platelet, and fresh frozen plasma administration. No association with thrombo-embolic events was found. ConclusionsPatients with active IE undergoing urgent SVR have significantly reduced hemostatic capacity before and after SVR. Hemostatic insufficiency post-SVR is related to bleeding and blood products transfusion. T-TAS may be helpful in assessment of periprocedural hemostasis in patients with IE undergoing SVR.

#4203 PREDICTION OF BLEEDING AND THROMBOSIS IN PATIENTS ON CHRONIC HEMODIALYSIS WITH THE TOTAL THROMBUS-FORMATION ANALYSIS SYSTEM

Abstract Background End-stage renal disease patients receiving hemodialysis (HD) are at increased risk of both bleeding and thrombotic complications. There are, however, few tools to help clinicians with risk stratification of the individual patient. Aims and Method To study if the Total Thrombus-formation Analysis System (T-TAS01), which measures thrombus formation in flowing whole blood inside a microchip [1], can be used to predict bleeding and thrombotic complications in patients on HD. Odds-ratios were calculated using the median split procedure. ROC curve analyses were performed to calculate the ability of T-TAS measurements performed at baseline to distinguish between patients with and without future bleeding or thrombotic complications. Results 176 patients on chronic HD were included and followed for one year; 11.4% were on antiplatelet drugs and 8.0% on continuous anticoagulation. Venous blood samples were taken at inclusion before dialysis procedure, and platelet-thrombus formation (PL-AUC; higher value reflects increased thrombogenicity) and platelet-fibrin thrombus formation (AR-OT; higher value reflects reduced thrombogenicity) were registered. Fifty-seven patients (32%) developed a bleeding complication, whereof 12 (6.8%) were ISTH major bleedings. The Odds-Ratio (OR; 95% CI) to develop any bleeding for patients with T-TAS01 measurements below (PL-AUC) or above (AR-OT) median were 7.67 (3.59-16.36) and 8.94 (4.10-19.51), respectively. ROC analyses to predict bleeding with T-TAS01 showed AUCs of 0.85 for all bleeding and 0.83 for ISTH major bleed (PL-AUC and AR-OT data combined). Furthermore, thirty-one patients (17.6%) developed a thrombotic complication, whereof 13 (7.4%) were acute coronary syndrome (ACS) or ischemic stroke (IS). The Odds-Ratio (OR; 95% CI) to develop any thrombosis for patients with T-TAS01 measurements below (PL-AUC) or above (AR-OT) median were 0.14 (0.05-0.40) and 0.28 (0.12-0.67), respectively. ROC analyses to predict thrombosis with T-TAS01 showed AUCs of 0.78 for all thrombosis and 0.62 for ACS/IS (PL-AUC and AR-OT data combined). Conclusion T-TAS01 is a promising tool to aid in the prediction of bleeding and thrombosis in HD patients.

The changes of blood platelet reactivity in the presence of Elaeagnus rhamnoides (L.) A. Nelson leaves and twig extract in whole blood

Uncontrolled blood platelet activation is an important risk factor of cardiovascular disease (CVDs). Various studies on phenolic compounds indicate that they have a protective effect on the cardiovascular system through different mechanisms, including the reduction of blood platelet activation. One of the plants that is particularly rich in phenolic compounds is sea buckthorn (Elaeagnus rhamnoides (L.) A. Nelson). The aim of the present study in vitro was to determine the anti-platelet properties of crude extracts isolated from leaves and twigs of E. rhamnoides (L.) A. Nelson in whole blood using flow cytometric and total thrombus-formation analysis system (T-TAS). In addition, the aim of our study was also analyze of blood platelet proteomes in the presence of different sea buckthorn extracts. A significant new finding is a decrease surface exposition of P-selectin on blood platelets stimulated by 10 µM ADP and 10 µg/mL collagen, and a decrease surface exposition of GPIIb/IIIa active complex on non-activated platelets and platelets stimulated by 10 µM ADP and 10 µg/mL collagen in the presence of sea buckthorn leaf extract (especially at the concentration 50 µg/mL). The twig extract also displayed antiplatelet potential. However, this activity was higher in the leaf extract than in the twig extract in whole blood. In addition, our present findings clearly demonstrate that investigated plant extracts have anticoagulant properties (measured by T-TAS). Therefore, the two tested extracts may be promising candidates for the natural anti-platelet and anticoagulant supplements.