Understanding thrombosis: the critical role of oxidative stress

Thrombosis, a leading contributor to global health burden, is a complex process involving the interplay of various cell types, including vascular endothelial cells, platelets, and red blood cells. Oxidative stress, characterized by an overproduction of reactive oxygen species (ROS), can significantly impair the function of these cells, thus instigating a cascade of events leading to thrombus formation. In this review, we comprehensively explore the role of oxidative stress within these cells, and its mechanistic contribution to thrombogenesis, and the application of oxidative therapy in inhibiting thrombosis. By dissecting the intricacies of oxidative stress and its impact on thrombosis, we underscore its potential as a viable therapeutic target. Therefore, further research in this direction is warranted to enhance our understanding and management of thrombotic disorders.

Bioinspired superhydrophobic surfaces with silver and nitric oxide-releasing capabilities to prevent device-associated infections and thrombosis

Bacteria-associated infections and thrombus formation are the two major complications plaguing the application of blood-contacting medical devices. Therefore, functionalized surfaces and drug delivery for passive and active antifouling strategies have been employed. Herein, we report the novel integration of bio-inspired superhydrophobicity with nitric oxide release to obtain a functional polymeric material with anti-thrombogenic and antimicrobial characteristics. The nitric oxide release acts as an antimicrobial agent and platelet inhibitor, while the superhydrophobic components prevent non-specific biofouling. Widely used medical-grade silicone rubber (SR) substrates that are known to be susceptible to biofilm and thrombus formation were dip-coated with fluorinated silicon dioxide (SiO2) and silver (Ag) nanoparticles (NPs) using an adhesive polymer as a binder. Thereafter, the resulting superhydrophobic (SH) SR substrates were impregnated with S-nitroso-N-acetylpenicillamine (SNAP, an NO donor) to obtain a superhydrophobic, Ag-bound, NO-releasing (SH-SiAgNO) surface. The SH-SiAgNO surfaces had the lowest amount of viable adhered E. coli (> 99.9 % reduction), S. aureus (> 99.8 % reduction), and platelets (> 96.1 % reduction) as compared to controls while demonstrating no cytotoxic effects on fibroblast cells. Thus, this innovative approach is the first to combine SNAP with an antifouling SH polymer surface that possesses the immense potential to minimize medical device-associated complications without using conventional systemic anticoagulation and antibiotic treatments.

Contribution of staphylococcal virulence factors in the pathogenesis of thrombosis

Staphylococci are responsible for many infections in humans, starting with skin and soft tissue infections and finishing with invasive diseases such as endocarditis, sepsis and pneumonia, which lead to high mortality. Patients with sepsis often demonstrate activated clotting pathways, decreased levels of anticoagulants, decreased fibrinolysis, activated endothelial surfaces and activated platelets. This results in disseminated intravascular coagulation and formation of a microthrombus, which can lead to a multiorgan failure. This review describes various staphylococcal virulence factors that contribute to vascular thrombosis, including deep vein thrombosis in infected patients. The article presents mechanisms of action of different factors released by bacteria in various host defense lines, which in turn can lead to formation of blood clots in the vessels.

Kidney disease in trials of perioperative tranexamic acid

STUDY OBJECTIVE

To assess how kidney disease is handled in randomized trials evaluating the safety and efficacy of perioperative tranexamic acid, and to evaluate its effects across levels of kidney function.

DESIGN

Systematic review and meta-analysis of randomized controlled trials.

SETTING

We screened studies from a previous comprehensive systematic review, and updated its search of PubMed, Embase, and Cochrane CENTRAL to July 31, 2023.

PATIENTS

Patients undergoing non-obstetric surgery.

INTERVENTIONS

Intravenous tranexamic acid compared to placebo or usual care without tranexamic acid.

MEASUREMENT

We summarized the handling of kidney disease in eligibility criteria, dose adjustments for kidney function, and effects of tranexamic acid on thrombotic events, seizures, and bleeding by subgroups of kidney function.

MAIN RESULTS

We evaluated 300 trials with 53,085 participants; 45,958 participants (86.6%) were enrolled in 228 trials (76.0%) that explicitly excluded patients with kidney disease. Definitions of kidney diseased used for exclusion varied widely. Most were non-specific and some corresponded to mild disease. Only 5 trials adjusted dosing for kidney function. Meta-analysis of two large trials found tranexamic acid unlikely to substantially increase or decrease the occurrence of thrombotic events in patients with eGFR <60 mL/min/1.73m2 (RR, 0.95; 95% CI: 0.83 to 1.07) or ≥ 60 mL/min/1.73m2 (RR, 1.00; 95% CI, 0.91 to 1.11; P for subgroup difference = 0.47), but both trials excluded patients with severe kidney disease. No analysis could be performed regarding seizure risk. One large trial in noncardiac surgery reported similar reduction in bleeding across subgroups of kidney function but excluded patients with creatinine clearance <30 mL/min.

CONCLUSIONS

The large evidence base supporting perioperative tranexamic acid suffers from broad and unjustified exclusion of patients with kidney disease. Typical perioperative dosing of tranexamic acid is likely safe and effective in patients with creatinine clearance >30 mL/min, but effects in more severe kidney disease are unknown.

Endovascular salvage of a chronically thrombosed hemodialysis arteriovenous fistula

For hemodialysis-dependent patients, maintaining functional access is a crucial lifeline. Thrombosed access should be salvaged as soon as possible to avoid complications of missed dialysis and to maximize the chance of success. Due to unfortunate circumstances, this patient's thrombosed arteriovenous fistula was not salvaged for 7 months. Despite the chronicity, endovascular salvage was achieved, with subsequent successful cannulation for maintenance dialysis. Contrary to conventional wisdom, chronically thrombosed arteriovenous fistulas can be salvaged through endovascular means with appropriate patient selection.

Management of prosthetic valve thrombosis with unfractionated heparin

BACKGROUND

Prosthetic valve thrombosis (PVT) is a severe and life-threatening complication. Surgery and thrombolytic therapy (TT) carry a high risk, and in several circumstances, optimal anticoagulation with unfractionated heparin (UFH) infusion may be an alternative treatment. This study aimed to assess the results of UFH in patients diagnosed with both obstructive and non-obstructive PVT.

METHODS

This observational retrospective study enrolled patients who had contraindications for TT and surgery underwent UFH therapy.

RESULTS

A total of 136 patients were enrolled [male: 55 (40.4%), mean age: 50.3 ± 14.6 years] in the study. In the successful group, 66 patients (48,5%) showed >75% regression in the thrombus burden without facing death or major non-fatal complications.In the unsuccessful group, 56 had less than a 50% reduction in thrombus load and 14 (10.3%) suffered major complications. The presence of obstruction (27.1% vs. 12.1%; p = 0.028), thrombus area 1.1 cm2 vs. 0.8 cm2; p = 0.005] and the duration of UFH treatment (15.1 vs. 11.8 (days); p = 0.005) were significantly higher in the unsuccessful UFH group.In multivariate regression analyses the presence of obstruction (RR: 3.088, p = 0.020), increased thrombus area (RR: 2.400; p = 0.015), and increased duration of UFH therapy (RR: 1.073 95%, p = 0.012) were identified as independent predictive parameters for a failed UFH therapy.

CONCLUSIONS

This study suggests that UFH therapy may be considered a relatively beneficial treatment strategy for some patients with PVT. The most significant factors affecting success are the obstructive nature and area of the thrombus.

Hypoalbuminemia as predictor of thrombotic events in patients with community-acquired pneumonia

BACKGROUND

Hypoalbuminemia complicates acute diseases and infections and is associated with a worst prognosis. The aim is to evaluate whether hypoalbuminemia is associated with higher incidence and risk of thrombotic events in community-acquired pneumonia.

METHODS

We retrospectively collected data from a prospective study investigating the incidence of thrombotic events in community-acquired pneumonia hospitalized patients from 2011 to 2016 at University-Hospital Policlinico Umberto I. Baseline characteristics and outcomes were collected. Incidence of outcomes were calculated. Kaplan-Meier curves were created, Cox model used to identify predictors for the outcomes, and competing risk analysis performed.

RESULTS

From a total of 231 patients, 130 (56.3%) and 101 (43.7%) had or not hypoalbuminemia. Age, proportion of female, BMI, major comorbidities, and severity of pneumonia were similar between two subgroups. A less proportion of patients with hypoalbuminemia received antithrombotic and statin therapy. Median hospital stay was 11 days in both subgroups. Patients with hypoalbuminemia had higher D-dimer and high- sensitivity C-reactive-protein values with an inverse relation between albumin values and these markers. Incidence of thrombotic events was 26 and 11 per 1000 patient-days in patient with and without hypoalbuminemia. At Cox model, hypoalbuminemia was associated with thrombotic events development in univariable (hazard ratio; 2.67, 95% confidence intervals, 1.30-5.40) and multivariable (hazard ratio 3.19; 95% confidence intervals, 1.48-6.89) analysis.

CONCLUSIONS

More than a half of patients with community acquired pneumonia had hypoalbuminemia that is associated with a doubled incidence and a three-fold increased risk of thrombotic events. The inverse relation between baseline albumin and D-dimer values confirms this association.

Pattern of disease expression in SLE patients with antiphospholipid antibodies: data from Indian Systemic Lupus Erythematosus Inception cohort (INSPIRE)

Antiphospholipid antibodies (APLA) are present in one-third of systemic lupus erythematosus (SLE) patients, and they are associated with both criteria and non-criteria manifestations. We studied the prevalence, clinical associations, and impact on mortality of APLA in SLE patients from India. Among the Indian SLE inception cohort (INSPIRE), patients who had data on all five routinely performed APLAs [lupus anticoagulant (LA), IgG and IgM anticardiolipin antibody (aCL) and anti-β2-glycoprotein I(β2GPI)] at enrolment were selected. Patients were divided into four categories based on the presence/absence of APLA associated manifestations and presence/absence of the APLA viz SLE-APS, SLE-APLA, SLE: events but no APLA, and SLE: no events, no APLA (reference group). 1035 SLE patients at least 1 APLA antibody was detected in 372 (35.9%). LA was present in 206 (19.9%), aCL in 126 (12.2%) and β2-GPI in 178 (17.2%). There were 88 thrombotic events in 83 patients (8.0%); 73 (82.9%) being arterial; APLA positivity was present in 37 (44.6%) [AOR 1.70 (1.054, 2.76)]. SLE-APS patients were younger and had higher mortality [AOR 4.11 (1.51, 11.3)], neuropsychiatric and hematologic disease. SLE-APLA also had a higher mortality rate [AOR 2.94 (1.06, 8.22)] than the reference group. The mortality was highest in the subset of patients with thrombotic events in the presence of APLA [AOR 7.67 (1.25, 46.9)]. The mere presence of APLA also conferred higher mortality even in the absence of thrombotic events [AOR 3.51 (1.43, 8.63)]. Hematologic manifestations (36.1%) were the most common non-criteria-manifestation. One-third of SLE patients have APLA and its presence is associated with non-criteria hematologic manifestations, arterial thrombosis and higher mortality rate.

Evaluation of arteriovenous fistula for hemodialysis with a new generation digital stethoscope: a pilot study

BACKGROUND AND AIMS

The management of complications of arteriovenous fistula (AVF) for hemodialysis, principally stenosis, remains a major challenge for clinicians with a substantial impact on health resources. Stenosis not infrequently preludes to thrombotic events with the loss of AVF functionality. A functioning AVF, when listened by a stethoscope, has a continuous systolic-diastolic low-frequency murmur, while with stenosis, the frequency of the murmur increases and the duration of diastolic component decreases, disappearing in severe stenosis. These evidences are strictly subjective and dependent from operator skill and experience. New generation digital stethoscopes are able to record sound and subsequently dedicated software allows to extract quantitative variables that characterize the sound in an absolutely objective and repeatable way. The aim of our study was to analyze with an appropriate software sounds from AVFs taken by a commercial digital stethoscope and to investigate the potentiality to develop an objective way to detect stenosis.

METHODS

Between September 2022 and January 2023, 64 chronic hemodialysis (HD) patients were screened by two blinded experienced examiners for recognized criteria for stenosis by Doppler ultrasound (DUS) and, consequently, the sound coming from the AVFs using a 3 M™ Littmann® CORE Digital Stethoscope 8570 in standardized sites was recorded. The sound waves were transformed into quantitative variables (amplitude and frequency) using a sound analysis software. The practical usefulness of the core digital stethoscope for a quick identification of an AVF stenosis was further evaluated through a pragmatic trial. Eight young nephrologist trainees underwent a simple auscultatory training consisting of two sessions of sound auscultation focusing two times on a "normal" AVF sound by placing the digital stethoscope on a convenience site of a functional AVF.

RESULTS

In 48 patients eligible, all sound components displayed, alone, a remarkable diagnostic capacity. More in detail, the AUC of the average power was 0.872 [95% CI 0.729-0.951], while that of the mean normalized frequency was 0.822 [95% 0.656-0.930]. From a total of 32 auscultations (eight different block sequences, each one comprising four auscultations), the young clinicians were able to identify the correct sound (stenosis/normal AVF) in 25 cases, corresponding to an overall accuracy of 78.12% (95% CI 60.03-90.72%).

CONCLUSIONS

The analysis of sound waves by a digital stethoscope permitted us to distinguish between stenotic and no stenotic AVFs. The standardization of this technique and the introducing of data in a deep learning algorithm could allow an objective and fast method for a frequent monitoring of AVF.

In vitro test methods for evaluating high molecular weight polyethylene oxide polymer induced hemolytic and thrombotic potential

To combat opioid abuse, the U.S. Food and Drug Administration (FDA) released a comprehensive action plan to address opioid addiction, abuse, and overdose that included increasing the prevalence of abuse-deterrent formulations (ADFs) in opioid tablets. Polyethylene oxide (PEO) has been widely used as an excipient to deter abuse via nasal insufflation. However, changes in abuse patterns have led to unexpected shifts in abuse from the nasal route to intravenous injection. Case reports identify adverse effects similar to thrombotic thrombocytopenic purpura (TTP) syndrome following the intravenous (IV) abuse of opioids containing PEO excipient. Increased risk of IV opioid ADF abuse compared to clinical benefit of the drug led to the removal of one opioid product from the market in 2017. Because many generic drugs containing PEO are still in development, there is interest in assessing safety consistent with generic drug regulation and unintended uses. Currently, there are no guidelines or in vitro assessment tools to characterize the safety of PEO excipients taken via intravenous injection. To create a more robust excipient safety evaluation tool and to study the mechanistic basis of HMW PEO-induced TMA, a dynamic in vitro test system involving blood flow through a needle model has been developed.

Integrating network pharmacology with microRNA microarray analysis to identify the role of miRNAs in thrombosis treated by the Dahuang Zhechong pill

BACKGROUND

Thrombotic diseases are the leading causes of death worldwide, urging for improvements in treatment strategies. Dahuang Zhechong pill (DHZCP) is a traditional Chinese medicine widely used for treating thrombotic diseases; however, the underlying mechanisms remain unclear. This study aimed to explore the potential mechanisms of DHZCP in treating thrombosis with a focus on bioinformatics and miRNAs.

METHODS

We used network pharmacology to explore the targets of thrombosis treated with DHZCP and performed microarray analysis to acquire miRNA profiles and predict the target genes in thrombin-stimulated MEG-01 cells treated with DHZCP. Based on the overlapping of targets, we carried out a component-target-miRNA network and enrichment analysis and validated the selected miRNAs and mRNAs using quantitative reverse transcription-polymerase chain reaction.

RESULTS

Our data showed 850 targets of 230 active ingredients of DHZCP and 1214 thrombosis-related genes; 235 targets were common. We identified 32 miRNAs that were regulated by thrombin stimulation but regulated reversely by DHZCP treatment in MEG-01 cells, and predicted 1846 targets with function annotation. We analyzed conjointly 23 integrating targets from network pharmacology and microarray. HIF1A, PIK3CA, MAPK1 and BCL2L1 emerged as key nodes in the network diagrams. We confirmed the differential expression of seven miRNAs, one mRNA (BCL2L1) and platelet surface protein.

CONCLUSIONS

This study showed that miRNAs and their targets, such as BCL2L1, played crucial roles in platelet activation during DHZCP intervention in thrombosis, highlighting their potential to alleviate platelet activation and increase cell apoptosis. The study's findings could help develop new strategies for improving thrombosis treatment.

Antiphospholipid syndrome, thrombosis, and vaccination in the COVID-19 pandemic

Thrombosis is one of the many signs of antiphospholipid syndrome (APS) and COVID-19 infection. Although the mechanisms contributing to thrombosis in APS and COVID-19 are relatively similar, this remains an open subject. Even now (when the COVID-19 pandemic has subsided), there is no conclusive solution to APS and COVID-19 co-occurrence. The presence of newly generated antiphospholipid antibodies (aPLs) in COVID-19 infection may or may not be connected to the diagnosis of APS. The prevalence of aPLs is substantial in severe COVID-19 but not related to thrombosis or a worse outcome. Adequate monitoring of antibody positivity over time is recommended for APL diagnosis. On the other hand, thrombosis and thrombocytopenia can rarely occur with vaccination with mRNA vaccines. Some studies have shown that COVID-19 immunization is well tolerated among APS patients who are triple-positive for aPL, which may comfort patients and referring physicians and lessen hesitation in unvaccinated APS/aPL-positive patients. In this narrative review, we will give an overview of the interaction between aPL-APS-COVID-19-thrombosis and related diagnostic insights learned during the pandemic.

Coronary artery bypass grafting (CABG) induces pro-inflammatory and immunomodulatory phenotype of platelets in the absence of a pro-aggregatory state

BACKGROUND

Coronary artery bypass grafting (CABG) is considered the choice treatment for patients suffering from coronary artery disease (CAD). In the inflammatory milieu of cardiopulmonary bypass (CPB), systemic inflammatory response syndrome (SIRS) can induce a platelet pro-inflammatory state which could exacerbate post-CABG inflammatory status while affecting hemostatic function in patients. Therefore, focusing on platelets, the study presented here attempted to evaluate the pro-inflammatory and immunomodulatory profile of platelets as well as pro-aggregatory status during CABG.

METHODS

Platelets from patients undergoing CABG were subjected to flowcytometry analysis to evaluate P-selectin and CD40L expressions and PAC-1 binding in five intervals of 24 h before surgery, immediately, 2 h, 24 h, and one week after surgery. Moreover, intra-platelet TGF-β1 was also examined with western blotting.

RESULTS

Data showed increases of P-selectin and CD40L expressions in patients, with the meaningful loss of platelet contents of TGF-β1 after CABG (p < 0.001), where the changes tended to recover by day 7 of surgery while remaining above baseline (p < 0.001). Meanwhile, no significant change in PAC-1 binding capacity was shown.

CONCLUSION

The study presented here suggests that although the release of pro-inflammatory substances from platelets during CABG supports the post-operative inflammatory state, platelets are not pro-aggregatory enough to enhance thrombotic events after surgery. Whilst these observations could be due to successful medical interventions to optimize hemostasis during and after surgery, post-CABG reversal of anticoagulant by protamine is considered as another factor that may also have contributed to preventing pro-aggregatory but not pro-inflammatory and immunomodulatory functions of platelets.

Protein disulfide isomerase uses thrombin-antithrombin complex as a template to bind its target protein and alter the blood coagulation rates

During inflammation and situations of cellular stress Protein Disulfide Isomerase (PDI) is released in the blood plasma from the platelet and endothelial cells to influence thrombosis. The addition of exogenous PDI makes the environment pro-thrombotic by inducing disulfide bond formation in specific plasma protein targets like vitronectin, factor V, and factor XI. However, the mechanistic details of PDI interaction with its target remain largely unknown. A decrease in the coagulation time was detected in activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) in addition to the purified recombinant PDI (175nM). The coagulation time can be controlled using an activator (quercetin penta sulfate, QPS) or an inhibitor (Quercetin 3-rutinoside, Q3R) of PDI activity. Likewise, the PDI variants that increase the PDI activity (H399R) decrease, and the variant with low activity (C53A) increases the blood coagulation time. An SDS-PAGE and western blot analysis showed that the PDI does not form a stable complex with either thrombin or Antithrombin (ATIII) but it uses the ATIII-thrombin complex as a template to bind and maintain its activity. A complete inhibition of thrombin activity on the formation of ATIII-thrombin-PDI complex, and the complex-bound PDI-catalyzed disulfide bond formation of the target proteins may control the pro- and anti-thrombotic role of PDI.

Hematocrit control and thrombotic risk in patients with polycythemia vera treated with ruxolitinib in clinical practice

Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by unregulated red blood cell production resulting in elevated hemoglobin and/or hematocrit levels. Patients often have symptoms such as fatigue, pruritus, and painful splenomegaly, but are also at risk of thrombosis, both venous and arterial. Ruxolitinib, a selective Janus kinase inhibitor, is approved by the US Food and Drug Administration as second-line cytoreductive treatment after intolerance or inadequate response to hydroxyurea. Although ruxolitinib has been widely used in this setting, limited data exist in the literature on ruxolitinib treatment patterns and outcomes among patients with PV in routine clinical practice. We report a retrospective, observational, cohort study of patients treated for PV with ruxolitinib across three US centers (academic and regional practice) from December 2014-December 2019. The study included 69 patients, with a median follow-up duration of 3.7 years (95% CI, 2.9-4.4). Our data demonstrate very high rates of hematocrit control (88% of patients by three months and 89% by six months); few patients required dose adjustments or suspension. No arterial thromboses were observed; however, the follow-up duration does not allow for the generation of meaningful conclusions from this. Three patients had thrombotic events; one was in the setting of a second malignancy, one post-operative, and a third related to prolonged immobility. We also found that 28% of patients initiated ruxolitinib as a result of poorly controlled platelet counts, second only to hydroxyurea intolerance (46%) as a reason to start therapy. In clinical practice, ruxolitinib continues to be effective in controlling hematocrit levels after three and six months of treatment in patients and is associated with low thrombotic risk.

Carboxyhemoglobin predicts oxygenator performance and imminent oxygenator change in extracorporeal membrane oxygenation

BACKGROUND

The continuous exposure of blood to a non-biological surface during extracorporeal membrane oxygenation (ECMO) may lead to progressive thrombus formation in the oxygenator, hemolysis and consequently impaired gas exchange. In most centers oxygenator performance is monitored only on a once daily basis. Carboxyhemoglobin (COHb) is generated upon red cell lysis and is routinely measured with any co-oximetry performed to surveille gas exchange and acid-base homeostasis every couple of hours. This retrospective cohort study aims to evaluate COHb in the arterial blood gas as a novel marker of oxygenator dysfunction and its predictive value for imminent oxygenator change.

RESULTS

Out of the 484 screened patients on ECMO 89, cumulatively requiring 116 oxygenator changes within 1833 patient days, including 19,692 arterial COHb measurements were analyzed. Higher COHb levels were associated with lower post-oxygenator pO2 (estimate for log(COHb): - 2.176 [95% CI - 2.927, - 1.427], p < 0.0001) and with a shorter time to oxygenator change (estimate for log(COHb): - 67.895 [95% CI - 74.209, - 61.542] hours, p < 0.0001). COHb was predictive of oxygenator change within 6 h (estimate for log(COHb): 5.027 [95% CI 1.670, 15.126], p = 0.004).

CONCLUSION

COHb correlates with oxygenator performance and can be predictive of imminent oxygenator change. Therefore, longitudinal measurements of COHb in clinical routine might be a cheap and more granular candidate for ECMO surveillance that should be further analyzed in a controlled prospective trial design.

Long-term incidence, risk factors and complications for venous thromboembolism in patients with systemic lupus erythematosus

AIM

To compare frequency, incidence rates (IR), risk factors and outcomes of a first venous thromboembolic event (VTE) between patients with systemic lupus erythematosus (SLE) and controls.

METHODS

Using state-wide longitudinal hospital data from Western Australia (WA), we recorded venous thrombosis (VT) and pulmonary embolism (PE) in patients with SLE (n = 1854, median age 40, 86% female) and matched hospitalised controls (n = 12,107, median age 40 years, females 88.6%) in the period 1985-2015. Results presented are medians, frequency, IR per 1000 person years (PY) and odds, rate, or adjusted hazard ratios (OR/RR/a-HR) with 95% confidence intervals (CI).

RESULTS

Patients with SLE had significantly higher odds (12.8 vs 3.3%; OR 4.26, CI 3.60-5.05) and IR for a first VTE (10.09 vs 1.52; RR 6.64; CI 5.56-7.79). Over the three study decades, the IR for PE declined in patients with SLE from 7.74 to 3.75/1000 PY (p < .01) with no changes observed for VT or in controls. VTE recurred more frequently in patients with SLE (24.1% vs 10.2 %) (p < .01). Antiphospholipid antibodies (aPL) (a-HR 4.24, CI 2.50-7.19), serositis (a-HR 2.70, CI 1.86-3.91), lupus nephritis (a-HR 1.75 CI 1.25-2.33) and thrombocytopenia (a-HR 1.65 (1.10-2.49) were the strongest disease risk factors for VTE only in patients with SLE, while arterial hypertension, smoking and obesity were independent VTE risk factors for both groups. VTE was not associated with an increased risk for arterial events, but PE increased the risk for pulmonary hypertension (PH) in both patients with SLE (a-HR 6.47, CI 3.73-11.23) and controls (a-HR 9.09, CI 3.50-23.63). VTE increased the risk of death in both patients with SLE (a-HR 2.02, CI 1.50-2.70) and controls (a-HR 6.63, CI 5.21-8.42) after 10 years of follow-up.

CONCLUSIONS

VTE affected 12.8% of patients with SLE at six times the VTE rate in controls with aPL as the strongest, but not the only risk factor in SLE. The risk of PH was increased in both groups following PE, but VTE did not associate with an increased risk of arterial events.

Five-Year Experience of Interwoven Self-Expanding Stent Implantation in Stenotic Kinking of Below the Knee Prosthetic Bypasses

PURPOSE

The purpose of this study was to evaluate the 5-year real-world results of Supera stent implantation in below the knee prosthetic bypasses (BKPBs). All the procedures were performed because of a history of recurrent thrombosis of the graft and significant stenotic kinking of the prosthesis during knee flexion. A Supera stent was implanted to prevent the next potential BKPB thrombosis.

MATERIALS AND METHODS

Fourteen patients were included in this single-center, retrospective observational cohort study. All patients underwent Supera stent implantation in infrainguinal prosthetic bypass between 2012 and 2017, due to a history of recurrent thrombosis and kinking of the prosthetic bypass.

RESULTS

Prior to Supera stent implantation procedure, all the patients had more than one episode of acute limb ischemia caused by thrombosis of the BKPB. The median number of BKPB thromboses prior to Supera stent implantation was 3 and ranged from 2 to 6. Technical success was achieved in all cases. Primary patency rates at 12, 24, 36 and 60 months were 71.4%, 57.1%, 57.1% and 14.3%, respectively. Secondary patency rates at 12, 24, 36 and 60 months were 78.6%, 64.3%, 64.3% and 35.7%, respectively. One stent fracture was reported during 60-month follow-up. Major amputation was performed in 6 patients in 5-year follow-up.

CONCLUSION

Supera stent in treatment of recurrent thrombosis of BKBP is a safe procedure with acceptable mid-term results. However, larger and comparable prospective studies are needed for broader analysis of this procedure.

Lipoxin A4 analogue, BML-111, reduces platelet activation and protects from thrombosis

Formyl peptide receptors (FPRs) are members of seven transmembrane G protein-coupled receptors superfamily that exhibit different responses based on the nature of stimulating ligand type. FPRs have been shown to be present in platelets and regulate their function. However, the effect of formyl peptide receptor 2 (FPR2/ALX) lipid ligands on platelets has not yet been addressed. Hence, we sought to study the role of FPR2/ALX ligand and lipoxin A4 lipid analogue, BML-111, in the modulation of platelet function and thrombus formation. Immunofluorescence microscopy showed subcellular distribution and peripheral mobilisation of FPR2/ALX in stimulated platelets. This variation in distribution was further confirmed using flow cytometry. BML-111 inhibited a range of platelet activities in a dose-dependent manner in response to several platelet agonists. This included aggregation, fibrinogen binding to integrin αIIbβ3, α-granule secretion, dense granule secretion, Ca2 + mobilisation and integrin αIIbβ3-mediated outside-in signaling. The selectivity of BML-111 for FPR2/ALX was confirmed using FPR2/ALX deficient mice in flow cytometry assays. In vitro thrombus formation was also inhibited by various concentrations of BML-111. Moreover, the levels of vasodilator stimulated phosphorylation (VASP-S157) increased significantly after BML-111 treatment in resting and stimulated platelets via protein kinase A (PKA) independently of cyclic adenosine monophosphate (cAMP) signaling. Together, our findings demonstrate the significance of BML-111 as a modulator of platelet function via FPR2/ALX and unravel the thrombo-protective potentials of BML-111 induced signaling against thrombo-inflammatory diseases.

Enhancement of NETosis by ACE2-cross-reactive anti-SARS-CoV-2 RBD antibodies in patients with COVID-19

BACKGROUND

High levels of neutrophil extracellular trap (NET) formation or NETosis and autoantibodies are related to poor prognosis and disease severity of COVID-19 patients. Human angiotensin-converting enzyme 2 (ACE2) cross-reactive anti-severe acute respiratory syndrome coronavirus 2 spike protein receptor-binding domain (SARS-CoV-2 RBD) antibodies (CR Abs) have been reported as one of the sources of anti-ACE2 autoantibodies. However, the pathological implications of CR Abs in NET formation remain unknown.

METHODS

In this study, we first assessed the presence of CR Abs in the sera of COVID-19 patients with different severity by serological analysis. Sera and purified IgG from CR Abs positive COVID-19 patients as well as a mouse monoclonal Ab (mAb 127) that can recognize both ACE2 and the RBD were tested for their influence on NETosis and the possible mechanisms involved were studied.

RESULTS

An association between CR Abs levels and the severity of COVID-19 in 120 patients was found. The CR Abs-positive sera and IgG from severe COVID-19 patients and mAb 127 significantly activated human leukocytes and triggered NETosis, in the presence of RBD. This NETosis, triggered by the coexistence of CR Abs and RBD, activated thrombus-related cells but was abolished when the interaction between CR Abs and ACE2 or Fc receptors was disrupted. We also revealed that CR Abs-induced NETosis was suppressed in the presence of recombinant ACE2 or the Src family kinase inhibitor, dasatinib. Furthermore, we found that COVID-19 vaccination not only reduced COVID-19 severity but also prevented the production of CR Abs after SARS-CoV-2 infection.

CONCLUSIONS

Our findings provide possible pathogenic effects of CR Abs in exacerbating COVID-19 by enhancing NETosis, highlighting ACE2 and dasatinib as potential treatments, and supporting the benefit of vaccination in reducing disease severity and CR Abs production in COVID-19 patients.

Venous thromboembolism in patients with acute myeloid leukemia: development of a predictive model

BACKGROUND

Patients with acute myeloid leukemia (AML) are at increased risk of venous thromboembolic events (VTE). However, thromboprophylaxis is largely underused.

OBJECTIVES

This study aimed to determine possible VTE development risk factors and to develop a novel predictive model.

METHODS

We conducted a retrospective cohort study of adult patients with newly diagnosed AML. We used univariate and multivariable logistic regression to estimate binary outcomes and identify potential predictors. Based on our final model, a dynamic nomogram was constructed with the goal of facilitating VTE probability calculation.

RESULTS

Out of 626 eligible patients with AML, 72 (11.5%) developed VTE during 6 months of follow-up. Six parameters were independent predictors: male sex (odds ratio [OR] 1.82, 95% confidence interval [CI]: 1.077-2.065), prior history of thrombotic events (OR 2.27, 95% CI: 1.4-4.96), international normalized ratio (OR 0.21, 95% CI: 0.05-0.95), Eastern Cooperative Oncology Group performance status (OR 0.71, 95% CI: 0.53-0.94), and intensive therapy (OR 2.05, 95% CI: 1.07-3.91). The C statistics for the model was 0.68. The model was adequately calibrated and internally validated. The decision-curve analysis suggested the use of thromboprophylaxis in patients with VTE risks between 8 and 20%.

CONCLUSION

We developed a novel and convenient tool that may assist clinicians in identifying patients whose VTE risk is high enough to warrant thromboprophylaxis.

Fibulin-1 promotes intimal hyperplasia after venous stent implantation through ACE mediated angiotensin II signaling

Objective

Stent intimal hyperplasia leads to in stent restenosis and thrombosis. This study determined whether Fibulin-1 activity in smooth muscle cells (SMCs) contributes to stent restenosis or thrombosis.

Methods

Stent implantation was conducted in a pig model. Target vessel samples were stained and analyzed by protein mass spectrometry. Cell experiments and Fibulin-1 SMC specific knockout mice (Fbln1SMKO) were used to investigate the mechanism of Fibulin-1 induced SMC proliferation and thrombosis.

Results

SMC proliferation and phenotypic transition are the main pathological changes of intimal hyperplasia in venous stents. Protein mass spectrometry analysis revealed a total of 67 upregulated proteins and 39 downregulated proteins in intimal hyperplasia after stent implantation compared with normal iliac vein tissues. Among them, Fibulin-1 ranked among the top proteins altered. Fibulin-1 overexpressing human SMCs (Fibulin-1-hSMCs) showed increased migration and phenotypic switching from contractile to secretory type and Fibulin-1 inhibition decreased the activity of SMCs. Mechanistically, Fibulin-1-hSMCs displayed increased levels of angiotensin converting enzyme (ACE) expression and angiotensin II signaling. Inhibition of ACE or angiotensin II signaling alleviated the migration of Fibulin-1-hSMCs. Using Fibulin-1 SMC specific knockout mice (Fbln1SMKO) and venous thrombosis model, we demonstrated that Fibulin-1 deletion attenuated intimal SMCs proliferation and thrombosis. Further, Fibulin-1 concentration was high in iliac vein compression syndrome (IVCS) patients treated with stent and was an independent predictor of venous insufficiency.

Conclusions

Fibulin-1 promotes SMC proliferation partially through ACE secretion and angiotensin II signaling after stent implantation. Fibulin-1 plays a role in venous insufficiency syndrome, implicating the protein in the detection and treatment of IVCS.

Protein adsorption on blood-contacting surfaces: A thermodynamic perspective to guide the design of antithrombogenic polymer coatings

Blood-contacting medical devices often succumb to thrombosis, limiting their durability and safety in clinical applications. Thrombosis is fundamentally initiated by the nonspecific adsorption of proteins to the material surface, which is strongly governed by thermodynamic factors established by the nature of the interaction between the material surface, surrounding water molecules, and the protein itself. Along these lines, different surface materials (such as polymeric, metallic, ceramic, or composite) induce different entropic and enthalpic changes at the surface-protein interface, with material wettability significantly impacting this behavior. Consequently, protein adsorption on medical devices can be modulated by altering their wettability and surface energy. A plethora of polymeric coating modifications have been utilized for this purpose; hydrophobic modifications may promote or inhibit protein adsorption determined by van der Waals forces, while hydrophilic materials achieve this by mainly relying on hydrogen bonding, or unbalanced/balanced electrostatic interactions. This review offers a cohesive understanding of the thermodynamics governing these phenomena, to specifically aid in the design and selection of hemocompatible polymeric coatings for biomedical applications. STATEMENT OF SIGNIFICANCE: Blood-contacting medical devices often succumb to thrombosis, limiting their durability and safety in clinical applications. A plethora of polymeric coating modifications have been utilized for addressing this issue. This review offers a cohesive understanding of the thermodynamics governing these phenomena, to specifically aid in the design and selection of hemocompatible polymeric coatings for biomedical applications.

Disentangling the riddle of systemic lupus erythematosus with antiphospholipid syndrome: blood transcriptome analysis reveals a less-pronounced IFN-signature and distinct molecular profiles in venous versus arterial events

INTRODUCTION

Systemic lupus erythematosus with antiphospholipid syndrome (SLE-APS) represents a challenging SLE endotype whose molecular basis remains unknown.

METHODS

We analysed whole-blood RNA-sequencing data from 299 patients with SLE (108 SLE-antiphospholipid antibodies (aPL)-positive, including 67 SLE-APS; 191 SLE-aPL-negative) and 72 matched healthy controls (HC). Pathway enrichment analysis, unsupervised weighted gene coexpression network analysis and machine learning were applied to distinguish disease endotypes.

RESULTS

Patients with SLE-APS demonstrated upregulated type I and II interferon (IFN) pathways compared with HC. Using a 100-gene random forests model, we achieved a cross-validated accuracy of 75.6% in distinguishing these two states. Additionally, the comparison between SLE-APS and SLE-aPL-negative revealed 227 differentially expressed genes, indicating downregulation of IFN-α and IFN-γ signatures, coupled with dysregulation of the complement cascade, B-cell activation and neutrophil degranulation. Unsupervised analysis of SLE transcriptome identified 21 gene modules, with SLE-APS strongly linked to upregulation of the 'neutrophilic/myeloid' module. Within SLE-APS, venous thromboses positively correlated with 'neutrophilic/myeloid' and 'B cell' modules, while arterial thromboses were associated with dysregulation of 'DNA damage response (DDR)' and 'metabolism' modules. Anticardiolipin and anti-β2GPI positivity-irrespective of APS status-were associated with the 'neutrophilic/myeloid' and 'protein-binding' module, respectively.

CONCLUSIONS

There is a hierarchical upregulation and-likely-dependence on IFN in SLE with the highest IFN signature observed in SLE-aPL-negative patients. Venous thrombotic events are associated with neutrophils and B cells while arterial events with DDR and impaired metabolism. This may account for their differential requirements for anticoagulation and provide rationale for the potential use of mTOR inhibitors such as sirolimus and the direct fIIa inhibitor dabigatran in SLE-APS.

Thrombosis inhibited by Corydalis decumbens through regulating PI3K-Akt pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Corydalis decumbens (Thunb.) Pers. was used as stasis-eliminating medicine traditionally to treat cardiovascular disease potentially attributed to its antithrombotic effect, but lack of pharmacological research on it.

AIM OF THE STUDY

To investigate the antithrombotic effect of C. decumbens and its preliminary mechanism.

MATERIALS AND METHODS

A carrageenan-induced mouse thrombus model and adenosine diphosphate stimulated platelet aggregation of rabbits were used to confirm the inhibitory effect of C. decumbens extract and compounds on thrombosis in vivo. Then, H2O2-induced human umbilical vein endothelial cells (HUVECs) injury model was further adopted to verify the effects of bioactive compounds in vitro. Moreover, in silico network pharmacology analyses and molecular docking were performed to predict the underlying mechanisms, targets, and pathways, and which were further confirmed through western blotting assay.

RESULTS

The administration of total extract (TE), total alkaloids (TA) and tetrahydropalmatine (TET) resulted in a significant reduction in black tail thrombus and congestion, along with a decreasing in platelet aggregation of rabbits. A superior antithrombotic effect indicated the bioactive fraction, and then the isolated bioactive compounds, TET and protopine (PRO) increased cell survival, and decreased reactive oxygen species (ROS) and lactate dehydrogenase (LDH) release in H2O2-induced HUVECs injury model. Moreover, the two alkaloids targeted 33 major proteins and influenced 153 pathways in network pharmacology prediction. Among these, HSP90AA1, COX-2, NF-κB/p65, MMP1 and HIF-1α were the key proteins and PI3K-Akt emerged as the major signaling pathway. Further western blotting results supported that five key proteins were downregulated by the two bioactive compounds in H2O2-stimulated HUVECs model.

CONCLUSION

C. decumbens exerted protective effect on thrombosis through inhibiting PI3K-Akt pathway and related key proteins, which supported the traditional use and presented potential antithrombotic alkaloids for further investigation.

The Proteasome Inhibitor Carfilzomib exerts anti-inflammatory and anti-thrombotic effects on the endothelium

BACKGROUND

Carfilzomib (CFZ) is a second-generation proteasome inhibitor used to treat multiple myeloma. Potent inhibition of the proteasome results in chronic proteotoxic endoplasmic reticulum (ER) stress, leading to apoptosis. While CFZ has improved survival rates in multiple myeloma, it is associated with an increased risk of cardiovascular adverse effects. While this has been putatively linked to cardiotoxicity, CFZ could potentially also exhibit adverse effects on the endothelium.

OBJECTIVE

To investigate the effects of CFZ on the endothelium METHODS: HUVECs were treated with CFZ and expression of relevant markers of ER stress, inflammation and thrombosis measured and functionally assessed.

RESULTS

CFZ failed to induce ER stress in HUVECs, but induced the expression of KLF-4, eNOS, tPA and thrombomodulin and reduced TNFα mediated ICAM-1 and tissue factor expression, suggesting a potential protective effect on the endothelium. Consistent with these observations, CFZ reduced leukocyte adhesion under shear stress and reduced Factor Xa generation and fibrin clot formation on the endothelium following TNFα treatment and inhibited Von Willebrand Factor (VWF) and Angiopoietin-2 exocytosis from Webiel-Palade bodies. Subsequently CFZ inhibited the formation of VWF-platelet strings and moreover, media derived from myeloma cell lines induced VWF release, a process also inhibited by CFZ.

CONCLUSION(S)

This data demonstrates that CFZ is unable to induce ER stress in confluent resting endothelial cells and can conversely attenuate the pro-thrombotic effects of TNFα on the endothelium. This study suggests that CFZ does not negatively alter HUVECs, and proteasome inhibition of the endothelium may offer a potential way to prevent thrombosis.

A retrospective multicentre clinical study on management of isolated splenic vein thrombosis: risks and benefits of anticoagulation

INTRODUCTION

Isolated splenic vein thrombosis (iSVT) is a common complication of pancreatic disease. Whilst patients remain asymptomatic, there is a risk of sinistral portal hypertension and subsequent bleeding from gastric varices if recanalisation does not occur. There is wide variation of iSVT treatment, even within single centres. We report outcomes of iSVT from tertiary referral hepatobiliary and pancreatic (HPB) units including the impact of anticoagulation on recanalisation rates and subsequent variceal bleeding risk.

METHODS

A retrospective cohort study including all patients diagnosed with iSVT on contrast-enhanced CT scan abdomen and pelvis between 2011 and 2019 from two institutions. Patients with both SVT and portal vein thrombosis at diagnosis and isolated splenic vein thrombosis secondary to malignancy were excluded. The outcomes of anticoagulation, recanalisation rates, risk of bleeding and progression to portal vein thrombosis were examined using CT scan abdomen and pelvis with contrast.

RESULTS

Ninety-eight patients with iSVT were included, of which 39 patients received anticoagulation (40%). The most common cause of iSVT was acute pancreatitis n = 88 (90%). The recanalisation rate in the anticoagulation group was 46% vs 15% in patients receiving no anticoagulation (p = 0.0008, OR = 4.7, 95% CI 1.775 to 11.72). Upper abdominal vascular collaterals (demonstrated on CT scan angiography) were significantly less amongst patients who received anticoagulation treatment (p = 0.03, OR = 0.4, 95% CI 0.1736 to 0.9288). The overall rate of upper GI variceal-related bleeding was 3% (n = 3/98) and it was independent of anticoagulation treatment. Two of the patients received therapeutic anticoagulation.

CONCLUSION

The current data supports that therapeutic anticoagulation is associated with a statistically significant increase in recanalisation rates of the splenic vein, with a subsequent reduction in radiological left-sided portal hypertension. However, all patients had a very low risk of variceal bleeding regardless of anticoagulation. The findings from this retrospective study should merit further investigation in large-scale randomised clinical trials.

Efficacy and safety of precision-guided transjugular extrahepatic portosystemic shunt (TEPS) in the management of cavernous transformation of the portal vein with portal hypertension: a case series

BACKGROUND AND AIMS

Performing a Transjugular intrahepatic portal system shunt (TIPS) in patients with portal vein cavernous transformation (CTPV) poses significant challenges. As an alternative, transjugular extrahepatic portal vein shunt (TEPS) may offer a potential solution for these patients. Nonetheless, the effectiveness and safety of TEPS remain uncertain. This case series study aimed to evaluate the efficacy and safety of TEPS in treating patients with CTPV portal hypertension complications.

METHODS

The study encompassed a cohort of 22 patients diagnosed with CTPV who underwent TEPS procedures. Of these, 13 patients manifested recurrent hemorrhagic episodes subsequent to conventional therapies, 8 patients grappled with recurrent or refractory ascites, and 1 patient experienced acute bleeding but refused endoscopic treatment. Comprehensive postoperative monitoring was conducted for all patients to rigorously evaluate both the technical and clinical efficacy of the intervention, as well as long-term outcomes.

RESULTS

The overall procedural success rate among the 22 patients was 95.5% (21/22).During the TEPS procedure, nine patients were guided by percutaneous splenic access, three patients were guided by percutaneous hepatic access, five patients were guided by transmesenteric vein access from the abdomen, and two patients were guided by catheter marking from the hepatic artery. Additionally, guidance for three patients was facilitated by pre-existing TIPS stents. The postoperative portal pressure gradient following TEPS demonstrated a statistically significant decrease compared to preoperative values (24.95 ± 3.19 mmHg vs. 11.48 ± 1.74 mmHg, p < 0.01).Although three patients encountered perioperative complications, their conditions ameliorated following symptomatic treatment, and no procedure-related fatalities occurred. During a median follow-up period of 14 months, spanning a range of 5 to 39 months, we observed four fatalities. Specifically, one death was attributed to hepatocellular carcinoma, while the remaining three were ascribed to chronic liver failure. During the follow-up period, no instances of shunt dysfunction were observed.

CONCLUSIONS

Precision-guided TEPS appears to be a safe and efficacious intervention for the management of CTPV.

Aspiration of thrombus for intermediate-risk subacute pulmonary embolism

Pulmonary embolism is the most common cardiovascular disease after myocardial infarction and stroke. Konstantinides (Eur Heart J 41(4):543-603, 2020) Current guidelines categorize patients with PE as being at low, intermediate, and high risk of early death, with the intermediate-risk group experiencing the greatest uncertainty regarding treatment recommendations. Rapid reduction of the thrombus load by thrombolysis significantly reduces symptoms and decreases mortality, but is accompanied by a high risk of bleeding. Meyer (N Engl J Med 370(15):1402-11, 2014) Mechanical thrombectomy (CDTE) have been proven safe and efficient, yet current ESC guidelines suggest the utilization of catheter interventions only for hypotensive patients with high bleeding risk, failed systemic thrombolysis, and cardiogenic shock or if a patient does not respond to conservative therapy Konstantinides (Eur Heart J 41(4):543-603, 2020). Here, we report a case of an intermediate-risk patient with pulmonary embolism who underwent thrombus aspiration and showed significant improvement in symptoms after treatment.

Development of 3D printed electrospun vascular graft loaded with tetramethylpyrazine for reducing thrombosis and restraining aneurysmal dilatation

Background

Small-diameter vascular grafts have become the focus of attention in tissue engineering. Thrombosis and aneurysmal dilatation are the two major complications of the loss of vascular access after surgery. Therefore, we focused on fabricating 3D printed electrospun vascular grafts loaded with tetramethylpyrazine (TMP) to overcome these limitations.

Methods

Based on electrospinning and 3D printing, 3D-printed electrospun vascular grafts loaded with TMP were fabricated. The inner layer of the graft was composed of electrospun poly(L-lactic-co-caprolactone) (PLCL) nanofibers and the outer layer consisted of 3D printed polycaprolactone (PCL) microfibers. The characterization and mechanical properties were tested. The blood compatibility and in vitro cytocompatibility of the grafts were also evaluated. Additionally, rat abdominal aortas were replaced with these 3D-printed electrospun grafts to evaluate their biosafety.

Results

Mechanical tests demonstrated that the addition of PCL microfibers could improve the mechanical properties. In vitro experimental data proved that the introduction of TMP effectively inhibited platelet adhesion. Afterwards, rat abdominal aorta was replaced with 3D-printed electrospun grafts. The 3D-printed electrospun graft loaded with TMP showed good biocompatibility and mechanical strength within 6 months and maintained substantial patency without the occurrence of acute thrombosis. Moreover, no obvious aneurysmal dilatation was observed.

Conclusions

The study demonstrated that 3D-printed electrospun vascular grafts loaded with TMP may have the potential for injured vascular healing.

Multimaterial decomposition in dual-energy CT for characterization of clots from acute ischemic stroke patients

BACKGROUND

Nowadays, there is no method to quantitatively characterize the material composition of acute ischemic stroke thrombi prior to intervention, but dual-energy CT (DE-CT) offers imaging-based multimaterial decomposition. We retrospectively investigated the material composition of thrombi ex vivo using DE-CT with histological analysis as a reference.

METHODS

Clots of 70 patients with acute ischemic stroke were extracted by mechanical thrombectomy and scanned ex vivo in formalin-filled tubes with DE-CT. Multimaterial decomposition in the three components, i.e., red blood cells (RBC), white blood cells (WBC), and fibrin/platelets (F/P), was performed and compared to histology (hematoxylin/eosin staining) as reference. Attenuation and effective Z values were assessed, and histological composition was compared to stroke etiology according to the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) criteria.

RESULTS

Histological and imaging analysis showed the following correlation coefficients for RBC (r = 0.527, p < 0.001), WBC (r = 0.305, p = 0.020), and F/P (r = 0.525, p < 0.001). RBC-rich thrombi presented higher clot attenuation in Hounsfield units than F/P-rich thrombi (51 HU versus 42 HU, p < 0.01). In histological analysis, cardioembolic clots showed less RBC (40% versus 56%, p = 0.053) and more F/P (53% versus 36%, p = 0.024), similar to cryptogenic clots containing less RBC (34% versus 56%, p = 0.006) and more F/P (58% versus 36%, p = 0.003) than non-cardioembolic strokes. No difference was assessed for the mean WBC portions in all TOAST groups.

CONCLUSIONS

DE-CT has the potential to quantitatively characterize the material composition of ischemic stroke thrombi.

RELEVANCE STATEMENT

Using DE-CT, the composition of ischemic stroke thrombi can be determined. Knowledge of histological composition prior to intervention offers the opportunity to define personalized treatment strategies for each patient to accomplish faster recanalization and better clinical outcomes.

KEY POINTS

• Acute ischemic stroke clots present different recanalization success according to histological composition. • Currently, no method can determine clot composition prior to intervention. • DE-CT allows quantitative material decomposition of thrombi ex vivo in red blood cells, white blood cells, and fibrin/platelets. • Histological clot composition differs between stroke etiology. • Insights into the histological composition in situ offer personalized treatment strategies.

Revisiting echocardiographic features of prosthetic heart valves: the necessity of correct differentiation of mono-leaflet vs. bileaflet mechanical heart valves in a case report

BACKGROUND

Mechanical heart valve replacement is a standard treatment for severe valvular disorders. The use of mono-leaflet valves has decreased recently. Recognizing the echocardiographic features of mono-leaflet and bileaflet valves is crucial for accurate complication diagnosis and proper management.

CASE PRESENTATION

A 65-year-old female with mono-leaflet mitral and bileaflet tricuspid valves underwent an echocardiographic assessment. This simple educational case provides a unique opportunity to compare the echocardiographic features of these valves within a single patient.

CONCLUSION

There is a crucial need for clinicians, particularly those in training, to differentiate between mono-leaflet and bileaflet mechanical heart valves adeptly. With mono-leaflet valves decreasing in prevalence, proficiency in recognizing the echocardiographic nuances of each type is imperative. Failure to do so may result in misdiagnoses and inappropriate management. This underscores the significance of continuous education and vigilance in echocardiographic assessments to ensure optimal patient care.

Under the dual effect of inflammation and pulmonary fibrosis, CTD-ILD patients possess a greater susceptibility to VTE

As an autoimmune disease, the persistent systemic inflammatory response associated with connective tissue disease (CTD) is involved in the development of venous thromboembolism (VTE). However, clinical data showed that the risk of VTE in patients differed between subtypes of CTD, suggesting that different subtypes may have independent mechanisms to promote the development of VTE, but the specific mechanism lacks sufficient research at present. The development of pulmonary fibrosis also contributes to the development of VTE, and therefore, patients with CTD-associated interstitial lung disease (CTD-ILD) may be at higher risk of VTE than patients with CTD alone or patients with ILD alone. In addition, the activation of the coagulation cascade response will drive further progression of the patient's pre-existing pulmonary fibrosis, which will continue to increase the patient's risk of VTE and adversely affect prognosis. Currently, the treatment for CTD-ILD is mainly immunosuppressive and antirheumatic therapy, such as the use of glucocorticoids and janus kinase-inhibitors (JAKis), but, paradoxically, these drugs are also involved in the formation of patients' coagulation tendency, making the clinical treatment of CTD-ILD patients with a higher risk of developing VTE challenging. In this article, we review the potential risk factors and related mechanisms for the development of VTE in CTD-ILD patients to provide a reference for clinical treatment and prevention.

Safety and Efficacy of Pegcetacoplan in Adult Patients with Paroxysmal Nocturnal Hemoglobinuria over 48 Weeks: 307 Open-Label Extension Study

INTRODUCTION

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening disease characterized by complement-mediated hemolysis and thrombosis. Pegcetacoplan, the first targeted complement component 3 (C3) PNH therapy, was safe and efficacious in treatment-naive and pre-treated patients with PNH in five clinical trials.

METHODS

The 307 open-label extension (OLE) study (NCT03531255) is a non-randomized, multicenter extension study of long-term safety and efficacy of pegcetacoplan in adult patients with PNH who completed a pegcetacoplan parent study. All patients received pegcetacoplan. Outcomes at the 48-week data cutoff (week 48 of 307-OLE or August 27, 2021, whichever was earlier) are reported. Hemoglobin concentrations, Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue scores, and transfusion avoidance were measured. Hemoglobin > 12 g/dL and sex-specific hemoglobin normalization (i.e., male, ≥ 13.6 g/dL; female, ≥ 12 g/dL) were assessed as percentage of patients with data available and no transfusions 60 days before data cutoff. Treatment-emergent adverse events, including hemolysis, were reported.

RESULTS

Data from 137 patients with at least one pegcetacoplan dose at data cutoff were analyzed. Mean (standard deviation [SD]) hemoglobin increased from 8.9 (1.22) g/dL at parent study baseline to 11.6 (2.17) g/dL at 307-OLE entry and 11.6 (1.94) g/dL at data cutoff. At parent study baseline, mean (SD) FACIT-Fatigue score of 34.1 (11.08) was below the general population norm of 43.6; scores improved to 42.8 (8.79) at 307-OLE entry and 42.4 (9.84) at data cutoff. In evaluable patients, hemoglobin > 12 g/dL occurred in 40.2% (43 of 107) and sex-specific hemoglobin normalization occurred in 31.8% (34 of 107) at data cutoff. Transfusion was not required for 114 of 137 patients (83.2%). Hemolysis was reported in 23 patients (16.8%). No thrombotic events or meningococcal infections occurred.

CONCLUSION

Pegcetacoplan sustained long-term improvements in hemoglobin concentrations, fatigue reduction, and transfusion burden. Long-term safety findings corroborate the favorable profile established for pegcetacoplan.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT03531255.

Thrombosis Tendency After Splenectomy in a Danish Family With Hemoglobin Volga, and a Literature Review

Hemoglobin (Hb) Volga is a rare, unstable β-chain hemoglobin variant (β27 Ala→Asp), causing chronic hemolytic anemia. This study presents two members of a Danish family, splenectomized due to Hb Volga at and with multiple thrombotic events. The proband was diagnosed with Hb Volga 9 years old and splenectomy was performed as a part of treatment. Throughout his life, he experienced multiple superficial thrombophlebitis, two episodes of distal deep venous thrombosis (DVT) on lower extremities (age 32 and 33) and a transient ischemic attack (TIA) presented as amaurosis fugax (age 51). Thrombophilia investigation was normal. The proband's son was diagnosed with Hb Volga and underwent splenectomy at the age of 6. Despite anticoagulation therapy, he suffered from multiple venous thromboembolic events in his youth and died of chronic pulmonary embolism (PE)/pulmonary hypertension combined with infection. Given the observed propensity for multiple thromboses in these two patients, a literature review was conducted investigating reported occurrence of thrombotic events in individuals with Hb Volga.

Currently 25 cases of Hb Volga are reported worldwide. The clinical symptoms primarily described are related to hemolytic anemia. Splenectomy is reported in 15 patients. Thromboses have previously been reported in only three patients who were also splenectomized. These cases involved DVT and PE, myocardial infarction, and an unspecified thrombotic event. The proband represents the first reported Hb Volga case with both venous and arterial thrombotic disorders. The exact mechanism underlying thrombotic tendency in patients with Hb Volga remains unknown, but it is probably associated with splenectomy.

Communication from the ISTH SSC Subcommittee on Hemostasis and Malignancy: A meta-analysis to assess the risk of bleeding and thrombosis following CAR T-cell therapy

BACKGROUND

Chimeric antigen receptor T cell (CAR T-cell) therapy is increasingly utilized for treatment of hematologic malignancies. Hematologic toxicities including thrombosis and bleeding complications have been reported. Accurate estimates for thrombotic and bleeding outcomes are lacking.

METHODS

We searched MEDLINE, EMBASE, and Cochrane CENTRAL up to February 2022 for studies reporting thrombotic or bleeding outcomes in patients receiving CAR T-cell therapy. Pooled event rates were calculated using a random-effects model. We performed subgroup analyses stratified by follow up duration, CAR T-cell target antigen, and underlying hematologic malignancy.

RESULTS

We included 47 studies with a total 7040 patients. High heterogeneity between studies precluded reporting of overall pooled rates of thrombotic and bleeding events. In studies with follow-up duration of ≤6 months, the pooled incidence of venous thrombotic events were 2.4% (95% CI 1.4-3.4, I2 = 0%) per patient-month whereas the rate was 0.1% (95% CI 0-0.1, I2 = 0%) per patient-month for studies with longer follow-up periods (> 6 months). The pooled incidences of any bleeding events per patient-month in studies with follow-up duration of ≤6 months and > 6 months were 1.9% (95% CI: 0.6-3.1, I2 = 78%) and 0.3% (95% CI: 0-0.8, I2 = 40%) respectively. Secondary analyses by CAR T-cell target antigen, underlying malignancy and primary outcome of the studies did not reveal significant differences in the rates of thromboembolism, any bleeding or major bleeding events.

CONCLUSION

The risk of both thrombosis and bleeding following CAR T-cell therapy appears to be highest in the initial months following infusion.

Impact of allele-selective silencing of von Willebrand factor in mice based on a single nucleotide allelic difference in von Willebrand factor

INTRODUCTION

Von Willebrand factor (VWF) plays a pathophysiological role in hemostatic disorders. Partial inhibition of the VWF gene through small interfering RNA (siRNA)-mediated allele-selective silencing could be a promising therapeutic strategy. For von Willebrand disease, allele-selectively inhibiting dominant-negative VWF-alleles might ameliorate the phenotype. For thrombotic disorders, partial VWF reduction can lower thrombotic risk, while avoiding bleeding. Previously, we demonstrated the feasibility of Vwf-silencing in homozygous C57BL/6J (B6) or 129S1/SvImJ (129S) mice. The present study investigated allele-selective Vwf-silencing in a complex heterozygous setting of crossed B6 and 129S mice and its subsequent hemostatic impact.

MATERIALS AND METHODS

Heterozygous B6.129S mice were treated with siRNAs targeting Vwf expressed from either B6- (siVwf.B6) or 129S-alleles (siVwf.129S). Plasma VWF and lung Vwf mRNA were determined. siVwf.B6-treated B6.129S mice were subjected to ferric chloride-induced mesenteric vessel thrombosis and tail-bleeding.

RESULTS

In B6.129S mice, siVwf.B6 reduced Vwf mRNA of the targeted B6-allele by 72% vs. only 12% of the non-targeted 129S-allele (41% total mRNA reduction), lowering plasma VWF by 46%. Oppositely, siVwf.129S reduced Vwf mRNA by 45%, now selectively inhibiting the 129S-allele over the B6-allele (58% vs. 9%), decreasing plasma VWF by 43%. The allele-selective VWF reduction by siVwf.B6 coincided with decreased thrombus formation in mesenteric arterioles, without prolonging tail-bleeding times.

CONCLUSIONS

This study demonstrates the feasibility of allele-selective Vwf-silencing in a heterozygous setting, achieving a controlled close to 50% reduction of plasma VWF. The observed thromboprotection and absence of prolonged bleeding times underline the potential of allele-selective Vwf-silencing as a therapeutic strategy in hemostatic disorders.

Risk factors for venous thrombosis after esophagectomy

BACKGROUND

Venous thrombosis (VT) after esophagectomy for esophageal cancer is an important complication, potentially leading to pulmonary embolism. However, there are few available information about the risk for the postsurgical VT.

METHODS

This study included 271 patients who underwent esophagectomy for esophageal cancer between 2006 and 2019. Contrast-enhanced computed tomography (CT) was performed for all patients on the seventh postoperative day to survey complications, including VT.

RESULTS

VT was radiologically visualized in 48 patients (17.7%), 8 of whom (16.7%) had pulmonary embolism. The thrombus disappeared in 42 patients, the thrombus size was unchanged in 5 patients, and 1 patient died. Multivariate analysis was performed on factors clinically considered to have a significant influence on thrombus formation. The analysis showed that CVC insertion via the femoral vein (odds ratio, 7.67; 95% CI, 2.64-22.27; P < 0.001), retrosternal reconstruction route (odds ratio, 3.94; 95% CI, 1.90-8.17; P < 0.001) and intraoperative fluid balance < 5 ml/kg/hr (odds ratio, 0.38; 95% CI, 0.17-0.85; P = 0.019) were independently related to VT.

CONCLUSIONS

Intraoperative fluid balance < 5 ml/kg/hr, along with CVC insertion via the femoral vein and retrosternal reconstruction may be potential risk factors for VT after esophagectomy.

Emerging artificial intelligence-aided diagnosis and management methods for ischemic strokes and vascular occlusions: A comprehensive review

Large-vessel occlusion (LVO) stroke is a promising field for the use of AI, especially machine learning (ML) because optimal results are highly dependent on timely diagnosis, communication, and treatment. In order to better understand the current state of artificial intelligence (AI) in relation to LVO strokes, its efficacy, and potential future applications, we searched relevant literature to perform a comprehensive evaluation of the topic. The databases PubMed, Embase, and Scopus were extensively searched for this review. Studies were then screened using title and abstract criteria and duplicate studies were excluded. By using pre-established inclusion and exclusion criteria, it was decided whether or not to include full-text papers in the final analysis. The studies were analyzed, and the relevant information was retrieved. In recognizing LVO on computed tomography, ML approaches were very accurate. There is a shortage of AI applications for thrombectomy patient selection, despite the fact that certain research accurately evaluates individual patient eligibility for endovascular therapy. Machine learning algorithms may reasonably predict clinical and angiographic outcomes as well as associated factors. AI has shown promise in the diagnosis and treatment of people who have just suffered a stroke. However, the usefulness of AI in management and forecasting remains restricted, necessitating more studies into machine learning applications that can guide decision making in the future.

Smaller nadroparin dose reductions required for patients with renal impairment: A multicenter cohort study

BACKGROUND

Guidelines advise 50 % and 25 % dose reduction of the therapeutic nadroparin dose (86 IU/kg) in patients with eGFR 15-29 and 30-60 ml/min respectively. For monitoring, peak anti-Xa levels are suggested. Data lack whether this results in therapeutic anti-Xa levels or in anti-Xa levels that are comparable to those of patients without renal impairment.

AIMS

To determine dose ranges in patients with renal impairment that result in therapeutic anti-Xa levels and to determine the percentage of the 86 IU/kg dose that results in anti-Xa levels normally occurring in patients without renal impairment.

METHODS

A retrospective cohort study was conducted in five hospitals. Patients ≥18 years of age, with an eGFR ≥ 15 ml/min were included. The first correctly sampled peak (i.e. 3-5 h after ≥ third administration, regardless of dose per patient) was included. Simulated prediction models were developed using multiple linear regression.

RESULTS

770 patients were included. eGFR and hospital affected the association between dose and anti-Xa level. The doses for peak anti-Xa levels of 0.75 IU/ml differed substantially between hospitals and ranged from 55 to 91, 65-359 and 68-168 IU/kg in eGFR 15-29, 30-60 and > 60 ml/min/1.73m2, respectively. In eGFR 15-29 and 30-60 ml/min/1.73m2, doses of 75 % and 91 % of 86 IU/kg respectively, were needed for anti-Xa levels normally occurring in patients with eGFR > 60 ml/min.

CONCLUSION

We advise against anti-Xa based dose-adjustments as long as anti-Xa assays between laboratories are not harmonized and an anti-Xa target range is not validated. A better approach might be to target levels similar to eGFR > 60 ml/min/1.73m2, which are achieved by smaller dose reductions.

Phenotypes in antiphospholipid syndrome: A hierarchical cluster analysis based on two independent databases

BACKGROUND

Antiphospholipid syndrome (APS) is a rare autoimmune disease characterized by thromboses at various sites and obstetric events associated with the persistent presence of antiphospholipid antibodies. The identification of clinical phenotypes in APS patients is a clinical need. In this study, we aimed to determine the clinical phenotypes of APS patients through an unsupervised analysis of two well-characterized cohorts of APS patients.

PATIENTS AND METHODS

APS phenotypes were defined by an ascending hierarchical cluster analysis to identify preferential associations between 18 types of organ involvement and clinical characteristics. This analysis was performed on an initial multi-center cohort of 1000 patients, with validation in a replication cohort of 435 patients.

RESULTS

The hierarchical analysis identified three APS phenotypes in both the initial and replication cohorts: an obstetric phenotype (n = 259 and n = 74 patients, respectively), a venous thrombosis phenotype, accounting for the largest number of patients (n = 461 and n = 297 patients, respectively), and a skin-central nervous system-heart phenotype (n = 280 and n = 64 patients, respectively). The clinical characteristics of the patients differed significantly between the three phenotypes, but there was no difference in antiphospholipid antibody profile between the groups.

CONCLUSIONS

We identified three phenotypes of APS defined based on preferential associations of organ involvements and differences in presentation. These observations may help clinicians to detect organ involvement and to manage treatment.

Comparison of the safety and efficacy for different regimens of pharmaco-prophylaxis among severely burned patients: a randomized controlled trial

PURPOSE

Venous thromboembolism (VTE) is a common complication in critically ill patients, including severe burn cases. Burn patients respond differently to medications due to pharmacokinetic changes. This study aims to assess the feasibility and safety of different VTE pharmaco-prophylaxis in patients admitted to the ICU with severe burns.

METHODS

A pilot, open-label randomized controlled trial was conducted on ICU patients with severe burns (BSA ≥ 20%). By using block randomization, patients were allocated to receive high-dose enoxaparin 30 mg q12hours (E30q12), standard-dose enoxaparin 40 mg q24hours (E40q24), or unfractionated heparin (UFH) 5000 Units q8hours. In this study, the primary outcomes assessed were the recruitment and consent rates, as well as bleeding or hematoma at both the donor and graft site. Additionally, secondary measures were evaluated to provide further insights.

RESULTS

Twenty adult patients out of 114 screened were enrolled and received E30q12 (40%), E40q24 (30%), and UFH (30%). The recruitment rate was one patient per month with a 100% consent rate. Donor site bleeding occurred in one patient (16.7%) in the UFH group. On the other hand, graft site bleeding was only reported in one patient (12.5%) who received E30q12. Major bleeding happened in two patients, one in E30q12 and one in the UFH group. Five patients (25.0%) had minor bleeding; two patients (25.0%) received E30q12, two patients E40q24, and one patient UFH. RBC transfusion was needed in four patients, two on E30q12 and two on UFH. Only one patient had VTE, while four patients died in the hospital.

CONCLUSION

The study observed a low recruitment rate but a high consent rate. Furthermore, there were no major safety concerns identified with any of the three pharmacologic prophylaxis regimens that were evaluated.

TRIAL REGISTRATION NUMBER

NCT05237726.

Non-severe burn injury causes sustained platelet hyperreactivity

Individuals who present to a hospital for treatment of a burn of any magnitude are more frequently hospitalised for ischemic heart disease, even decades after injury. Blood platelets are key mediators of cardiovascular disease. To investigate platelet involvement in post-burn cardiovascular risk, platelet reactivity was assessed in patients at 2- and 6-weeks after non-severe (TBSA < 20%) burn injury, and in a murine model 30 days after 8% TBSA full-thickness burn injury. Platelets were stimulated with canonical agonists and function reported by GPIIb/IIIa PAC1-binding site, CD62P expression, and formation of monocyte-platelet aggregates. In vivo thrombosis in a modified Folts model of vascular injury was assessed. Burn survivors had elevated frequencies of circulating monocyte-platelet aggregates, and platelets were hyperreactive, primarily to collagen stimulation. Burn plasma did not cause hyper-reactivity when incubated with control platelets. Platelets from burn injured mice also demonstrated increased response to collagen peptides but did not show any change in thrombosis following vascular injury. This study demonstrates the persistence of a small but significant platelet hyperreactivity following burn injury. Although our data does not suggest this heightened platelet sensitivity modulates thrombosis following vascular injury, the contribution of sub-clinical platelet hyperreactivity to accelerating atherogenesis merits further investigation.

Natural Anticoagulant Protein Levels in Patients With Beta-Thalassemia Major: A Case-Control Study

Background

β-thalassemia is a group of inherited blood disorders that affect the production of β-globin chains, leading to the reduction or absence of these chains. One of the complications observed in patients with β-thalassemia major (β-TM) is thrombosis, especially in those who receive frequent blood transfusions. This may be due to a decrease in the levels of the natural anticoagulants: protein C (PC), total protein S (PS), and antithrombin (AT).

Methods

In this case-control study, patients with β-TM, who had received at least 20 packed cell transfusions during their lifetime, were included. Patients with other underlying diseases like bleeding or thrombotic disorders were excluded. Totally, 118 patients with β-TM and 120 healthy individuals were included.

Results

The mean level of PC and AT was significantly lower in patients with β-TM (48.2 ± 65.4 and 57.42 ± 13.6, respectively) compared to the control group (97.1 ± 21.46 and 81.79 ± 14.3, respectively), with P value of 0.001 and 0.01, respectively. Although the difference was not statistically significant (P = 0.1), a similar trend was observed for total PS (61.12 ± 21.12 for patients versus 72.2 ± 35.2 for the control group). Of note, the decrease in PC, AT, and total PS levels compared to the control group was 50.36%, 27.5%, and 15.34%, respectively.

Conclusions

It seems that β-TM patients who receive prolonged blood transfusions frequently are at an increased risk of decreased in natural anticoagulants levels and therefore potentially are at risk of thrombosis.

The effects of dienogest and combined oral contraceptives on protein S-specific activity in endometriosis patients

OBJECTIVE

One serious side effect of combined oral contraceptives (COCs) is venous thromboembolism. Reduced activity in activated protein C-related coagulation pathways is attributable to low protein S activity in one-third of Japanese patients with deep vein thrombosis. Herer, we quantified the behavior of protein S-specific activity in response to dienogest (DNG) and COCs using the protein S-specific activity assay system to explore its potential utility as a thrombosis marker.

STUDY DESIGN

This was a prospective cohort study. Female patients aged 20 - 49 years who were starting drug treatment for endometriosis using DNG or COCs were enrolled. Blood samples were taken before treatment and at the first, third, and sixth months of treatment. To analyze the primary endpoints, changes in total protein S antigen levels, total protein S activity, and protein S-specific activity from baseline to each time point were estimated using a linear mixed-effects model. All statistical analyses were performed in the SAS software version 9.4 (SAS Institute, Cary, NC). A two-sided P < 0.05 was considered statistically significant.

RESULTS

64 patients took DNG and 34 patients took COCs. Protein S-specific activity did not change significantly from baseline in the six months after treatment started in either group. In the DNG group, total protein S activity and total protein S antigen levels increased slightly from baseline levels after the treatment. The means for total protein S activity and total protein S antigen levels in the COC group remained within reference limits, but they both decreased markedly in the first month and stayed low. Protein S-specific activity in four women remaind below the reference limit throughout the whole study period, suggesting they may have potential protein S deficiencies.

CONCLUSION

The effects of DNG on protein S were negligible, though both total protein S activity and antigen levels decreased soon after COC treatment began and remained low. As there was no VTE event during the study, further studies with larger numbers of patients will be needed to confirm that protein S-specific activity can be a surrogate maker of VTE risk.

Risk of thrombosis, hemorrhage and leukemic transformation in patients with myeloproliferative neoplasms: A nationwide longitudinal cohort study

INTRODUCTION

There are few large-scale, population-based studies detailing the risks of thrombosis, hemorrhage, leukemic transformation in patients with myeloproliferative neoplasms (MPNs), including essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF).

METHODS

We performed a nationwide longitudinal cohort study using the Korean National Health Insurance System (NHIS) database. MPN patients (n = 11,991) and their 1:4 age- and sex-matched controls (n = 47,964) were enrolled. The risk of thrombosis, hemorrhage, leukemic transformation was estimated using a Cox proportional hazards regression, and stratified analyses were performed for related factors.

RESULTS

During a median of 7.8 years of follow-up, 30.1 % of MPN patients (3614/11,991) and 19.0 % of the matched controls (9141/47,964) developed arterial thrombosis, 11.6 % of MPN patients (1397/11,991) and 6.4 % of the matched controls (3099/47,964) developed venous thrombosis and 18.7 % of MPN patients (2251/11,991) and 12.1 % of the matched controls (5836/47,964) developed hemorrhage. 4.9 % of MPN patients (597/11,991) and 0.1 % of matched controls (50/47,964) developed leukemia. The overall risk of developing thrombosis, hemorrhage, leukemic transformation was higher in MPN patients (adjusted hazard ratio [aHR] 1.695, 95 % confidence interval [CI]: 1.629-1.765 for arterial thrombosis, aHR 1.963, 95 % CI: 1.838-2.096 for venous thrombosis, and aHR 1.714, 95 % CI: 1.630-1.802 for hemorrhage) than in the controls. Patients with MPNs had a 10-year cumulative incidence of leukemic transformation of 6.2 %.

CONCLUSION

The patients with MPNs have a higher risk of thrombosis, hemorrhage, and leukemic transformation than matched controls. Strategies are warranted to reduce the risk of thrombosis, hemorrhage, and leukemic transformation in MPN patients.

Shear Histories Alter Local Shear Effects on Thrombus Nucleation and Growth

Our goal was to determine the impact of physiological and pathological shear histories on platelet nucleation and thrombus growth at various local shear rates. We designed and characterized a microfluidic device capable of subjecting platelets to shear histories reaching as high as 6700 s- 1 in a single passage. Time-lapse videos of platelets and thrombi are captured using fluorescence microscopy. Thrombi are tracked, and the degree of thrombosis is evaluated through surface coverage, platelet nucleation maps, and ensemble-averaged aggregate areas and intensities. Surface coverage rates were the lowest when platelets deposited at high shear rates following a pathological shear history and were highest at low shear rates following a pathological shear history. Early aggregate area growth rates were significantly larger for thrombi developing at high shear following physiological shear history than at high shear following a pathological shear history. Aggregate vertical growth was restricted when depositing at low shear following a pathological shear history. In contrast, thrombi grew faster vertically following physiological shear histories. These results show that physiological shear histories pose thrombotic risks via volumetric growth, and pathological shear histories drastically promote nucleation. These findings may inform region-based geometries for biomedical devices and refine thrombosis simulations.

Impact of very low dose rivaroxaban in addition to dual antiplatelet therapy on endogenous fibrinolysis in acute coronary syndrome: The VaLiDate-R study

BACKGROUND

Impaired endogenous fibrinolysis is adverse cardiovascular risk factor in acute coronary syndrome (ACS) patients. Addition of very low dose rivaroxaban (VLDR) to dual antiplatelet therapy (DAPT) reduces cardiovascular events but increases bleeding.

OBJECTIVE

We aimed to assess whether addition of VLDR to DAPT can enhance endogenous fibrinolysis.

METHODS

In a prospective, open-label trial, we assessed endogenous fibrinolysis in whole blood, in 549 patients with ACS using the Global Thrombosis Test (GTT) and Thromboelastography (TEG). Patients (n = 180) who demonstrated impaired endogenous fibrinolysis (lysis time [LT] >2000s with the GTT) were randomised 1:1:1 to (i) clopidogrel 75 mg daily; (ii) clopidogrel 75 mg daily plus rivaroxaban 2.5 mg twice daily; or (iii) ticagrelor 90 mg twice daily, for 30 days, in addition to aspirin. Fibrinolytic status was assessed at 0, 2, 4 and 8 weeks. The primary outcome was the change in LT from admission to week 4. We also measured thrombotic occlusion time (OT) at high shear, and rivaroxaban level.

RESULTS

There was no difference between the groups with respect to LT or clot lysis with TEG, and no change in these parameters compared to baseline during study drug allocation. In the rivaroxaban plus clopidogrel group, OT was prolonged compared to the other groups, although rivaroxaban levels were low, suggesting non-compliance.

CONCLUSION

Addition of rivaroxaban 2.5 mg twice daily to DAPT does not affect endogenous fibrinolysis of thrombus formed at either high or low shear. Further studies are needed to determine whether higher doses of rivaroxaban can favourably modulate fibrinolysis.

CONDENSED ABSTRACT

Impaired endogenous fibrinolysis is a strong risk factor in ACS. We aimed to assess whether adding very low dose rivaroxaban (VLDR) to DAPT can enhance fibrinolysis. Fibrin and clot lysis were assessed in whole blood. ACS patients with impaired fibrinolysis were randomised 1:1:1 to clopidogrel 75 mg daily; clopidogrel 75 mg plus VLDR; or ticagrelor 90 mg twice daily, in addition to aspirin. At 30-days, there was no difference in lysis time between the groups, nor change from baseline. VLDR does not improve fibrinolysis at high or low shear. Further studies are needed to determine whether alternative antithrombotic regimens can enhance endogenous fibrinolysis.