Inflammation modifies the platelet reactivity among thrombocytopenia patients undergoing percutaneous coronary intervention

Percutaneous coronary intervention (PCI) patients combined with thrombocytopenia (TP) are usually considered to be at low ischemic risk, receiving less proper antiplatelet therapy. However, recent studies reported a paradoxical phenomenon that PCI patients with TP were prone to experience thrombotic events, while the mechanisms and future treatment remain unclear. We aim to investigate whether inflammation modifies platelet reactivity among these patients. Consecutive 10 724 patients undergoing PCI in Fuwai Hospital were enrolled throughout 2013. High-sensitivity C-reactive protein (hsCRP) ≥2 mg/L was considered inflammatory status. TP was defined as platelet count <150×109/L. High on-treatment platelet reactivity (HTPR) was defined as adenosine diphosphate-induced platelet maximum amplitude of thromboelastogram >47mm. Among 6617 patients finally included, 879 (13.3%) presented with TP. Multivariate logistic regression demonstrated that patients with TP were associated with a lower risk of HTPR (odds ratio [OR] 0.64, 95% confidence interval [CI] 0.53-0.76) than those without TP in the overall cohort. In further analysis, among hsCRP <2 mg/L group, patients with TP exhibited a decreased risk of HTPR (OR 0.53, 95% CI 0.41-0.68); however, in hsCRP ≥2mg/L group, TP patients had a similar risk of HTPR as those without TP (OR 0.83, 95% CI 0.63-1.08). Additionally, these results remain consistent across subgroups, including patients presenting with acute coronary syndrome and chronic coronary syndrome. Inflammation modified the platelet reactivity of PCI patients with TP, providing new insights into the mechanisms of the increased thrombotic risk. Future management for this special population should pay more attention to inflammation status and timely adjustment of antiplatelet therapy in TP patients with inflammation.

Hemostatic imbalance induced by tamoxifen in estrogen receptor-positive breast cancer patients: An observational study

BACKGROUND

Estrogen receptor (ER)-positive (ER+) breast cancer accounts for approximately 75% of all breast cancers. Tamoxifen, a selective estrogen receptor modulator, is the standard adjuvant treatment. Although better tolerated than aromatase inhibitors, tamoxifen increases the risk of venous thromboembolism (VTE) 1.4-fold.

AIM

To assess the hemostatic imbalance induced by tamoxifen in adjuvant treatment of ER+ breast cancer.

METHOD

Twenty-five patients in remission from ER+ breast cancer under tamoxifen were included. One hundred and thirty one age- and BMI-matched healthy controls were included to establish reference ranges of thrombin generation assay (TGA) parameters. TGA was performed in the absence and presence of exogenous activated protein C (APC) to calculate the normalized APC sensitivity ratio (nAPCsr), a marker of APC resistance.

RESULTS

All TG parameters except the endogenous thrombin potential (ETP) (-APC) were significantly impacted by tamoxifen (p < 0.001). In absence of APC, regardless of TGA parameters, at least 50% of results were outside the reference ranges except for ETP, which was above the upper reference limit in only two individuals. The most impacted parameter was the Peak Height with 52% (-APC) and 80% (+APC) of results above the upper reference range limit, respectively. The nAPCsr was significantly higher in tamoxifen users (mean ± standard deviation = 3.18 ± 0.91) compared to the control group (2.19 ± 0.92, p < 0.0001).

CONCLUSION

This observational study showed that patients in remission from ER+ breast cancer taking tamoxifen had altered thrombin generation, as well as an acquired APC resistance. Moreover, this is the first study using the validated ETP-based APC resistance assay in tamoxifen-treated patients.

Increase in venous thromboembolism in SARS-CoV-2 infected lung tissue: proteome analysis of lung parenchyma, isolated endothelium, and thrombi

AIMS

COVID-19 pneumonia is characterized by an increased rate of deep venous thrombosis and pulmonary embolism. To better understand the pathophysiology behind thrombosis in COVID-19, we performed proteomics analysis on SARS-CoV-2 infected lung tissue.

METHODS

Liquid chromatography mass spectrometry was performed on SARS-CoV-2 infected postmortem lung tissue samples. Five protein profiling analyses were performed: whole slide lung parenchyma analysis, followed by analysis of isolated thrombi and endothelium, both stratified by disease (COVID-19 versus influenza) and thrombus morphology (embolism versus in situ). Influenza autopsy cases with pulmonary thrombi were used as controls.

RESULTS

Compared to influenza controls, both analyses of COVID-19 whole-tissue and isolated endothelium showed upregulation of proteins and pathways related to liver metabolism including urea cycle activation, with arginase being among the top upregulated proteins in COVID-19 lung tissue. Analysis of isolated COVID-19 thrombi showed significant downregulation of pathways related to platelet activation compared to influenza thrombi. Analysis of isolated thrombi based on histomorphology shows that in situ thrombi have significant upregulation of coronavirus pathogenesis proteins.

CONCLUSIONS

The decrease in platelet activation pathways in severe COVID-19 thrombi suggests a relative increase in venous thromboembolism, as thrombi from venous origin tend to contain fewer platelets than arterial thrombi. Based on histomorphology, in situ thrombi show upregulation of various proteins related to SARS-CoV-2 pathogenesis compared to thromboemboli, which may indicate increased in situ pulmonary thrombosis in COVID-19. Therefore, this study supports the increase of venous thromboembolism without undercutting the involvement of in situ thrombosis in severe COVID-19.

Real-world experience of direct oral anticoagulant use in a single pediatric center

BACKGROUND

Pediatric venous thromboembolism has increased by 130%-200%, specifically in hospitalized children, and direct oral anticoagulants (DOACs) offer several therapeutic advantages.

METHODS

This study aims to evaluate the real-world epidemiological and outcome data from a retrospective review of pediatric patients treated with DOACs from January 1, 2013 to December 31, 2022. In this single-center, IRB-approved study, 65 patients were identified and analyzed using SPSS statistical software, and a descriptive statistical analysis was conducted.

RESULTS

Of the 65 patients, 37% were on apixaban, 61.5% were on rivaroxaban, and 1.5% were on dabigatran. Per the 2023 ISTH outcome definitions, one (2%) patient had a major bleeding episode, six (9%) had clinically relevant non-major bleeding, three (5%) patients had patient-important heavy menstrual bleeding (HMB), and one (1.5%) patient had minor bleeding. Seven (19%) of 37 postmenarchal patients had evidence of HMB. Six (9.2%) patients had recurrent venous thromboembolism while on a DOAC (one was on apixaban, and five were on rivaroxaban) and were transitioned to other forms of anticoagulation.

CONCLUSION

Thus, bleeding rates after DOAC therapy are comparable to previous DOAC trials, as well as other anticoagulants in pediatrics. HMB is an important outcome measure and should continue to be investigated. This study reports a higher rate of recurrent thrombosis (9.2%) compared to other trials. However, this observation may be attributed to patients who had ongoing risk factors, as well as a longer duration of study follow-up. Additional multicentered outcome studies evaluating DOAC use in children are needed to determine long-term recurrence and HMB risks.

Evaluation of the Relationship Between Radial Artery Intima Media Thickness and Complications at the Intervention Site After Radial Angiography

The present study investigated the relationship between pre-procedural radial intima-media thickness (rIMT) and radial artery thrombosis (RAO) in patients undergoing angiography using a transradial approach (TRA). Patients (n = 90) who underwent cerebral or peripheral arterial angiography using TRA were included in the study. Ultrasonographic evaluation was performed before and 12 h after the procedure. Preoperative rIMT measurement was performed at the distal radial artery. Presence of radial artery occlusion was evaluated by ultrasonography after radial catheterization and revealed occlusive thrombus in the radial artery in 13 patients. rIMT was found to be statistically significantly higher in patients with thrombus (P < .05). When it was evaluated whether there was a correlation between age and rIMT, a positive significant correlation was found (P < .01). Our study suggests that increase of rIMT may be a risk factor for RAO in the intervention area. Before the procedure, ultrasound (US) assessment of the radial artery may be useful in determining the risk of occlusion. Thus, RAO-related technical risk factors (procedure time, number of punctures, sheath thickness, etc.) can be managed more carefully in patients having radial angiography.

Monocyte-Mediated Thrombosis Linked to Circulating Tissue Factor and Immune Paralysis in COVID-19

BACKGROUND

SARS-CoV-2 infections cause COVID-19 and are associated with inflammation, coagulopathy, and high incidence of thrombosis. Myeloid cells help coordinate the initial immune response in COVID-19. Although we appreciate that myeloid cells lie at the nexus of inflammation and thrombosis, the mechanisms that unite the two in COVID-19 remain largely unknown.

METHODS

In this study, we used systems biology approaches including proteomics, transcriptomics, and mass cytometry to define the circulating proteome and circulating immune cell phenotypes in subjects with COVID-19.

RESULTS

In a cohort of subjects with COVID-19 (n=35), circulating markers of inflammation (CCL23 [C-C motif chemokine ligand 23] and IL [interleukin]-6) and vascular dysfunction (ACE2 [angiotensin-converting enzyme 2] and TF [tissue factor]) were elevated in subjects with severe compared with mild COVID-19. Additionally, although the total white blood cell counts were similar between COVID-19 groups, CD14+ (cluster of differentiation) monocytes from subjects with severe COVID-19 expressed more TF. At baseline, transcriptomics demonstrated increased IL-6, CCL3, ACOD1 (aconitate decarboxylase 1), C5AR1 (complement component 5a receptor), C5AR2, and TF in subjects with severe COVID-19 compared with controls. Using stress transcriptomics, we found that circulating immune cells from subjects with severe COVID-19 had evidence of profound immune paralysis with greatly reduced transcriptional activation and release of inflammatory markers in response to TLR (Toll-like receptor) activation. Finally, sera from subjects with severe (but not mild) COVID-19 activated human monocytes and induced TF expression.

CONCLUSIONS

Taken together, these observations further elucidate the pathological mechanisms that underlie immune dysfunction and coagulation abnormalities in COVID-19, contributing to our growing understanding of SARS-CoV-2 infections that could also be leveraged to develop novel diagnostic and therapeutic strategies.

Differential Impact In Vivo of Pf4-ΔCre-Mediated and Gp1ba-ΔCre-Mediated Depletion of Cyclooxygenase-1 in Platelets in Mice

BACKGROUND

Low-dose aspirin is widely used for the secondary prevention of cardiovascular disease. The beneficial effects of low-dose aspirin are attributable to its inhibition of platelet Cox (cyclooxygenase)-1-derived thromboxane A2. Until recently, the use of the Pf4 (platelet factor 4) Cre has been the only genetic approach to generating megakaryocyte/platelet ablation of Cox-1 in mice. However, Pf4-ΔCre displays ectopic expression outside the megakaryocyte/platelet lineage, especially during inflammation. The use of the Gp1ba (glycoprotein 1bα) Cre promises a more specific, targeted approach.

METHODS

To evaluate the role of Cox-1 in platelets, we crossed Pf4-ΔCre or Gp1ba-ΔCre mice with Cox-1flox/flox mice to generate platelet Cox-1-/- mice on normolipidemic and hyperlipidemic (Ldlr-/-) backgrounds.

RESULTS

Ex vivo platelet aggregation induced by arachidonic acid or adenosine diphosphate in platelet-rich plasma was inhibited to a similar extent in Pf4-ΔCre Cox-1-/-/Ldlr-/- and Gp1ba-ΔCre Cox-1-/-/Ldlr-/- mice. In a mouse model of tail injury, Pf4-ΔCre-mediated and Gp1ba-ΔCre-mediated deletions of Cox-1 were similarly efficient in suppressing platelet prostanoid biosynthesis. Experimental thrombogenesis and attendant blood loss were similar in both models. However, the impact on atherogenesis was divergent, being accelerated in the Pf4-ΔCre mice while restrained in the Gp1ba-ΔCres. In the former, accelerated atherogenesis was associated with greater suppression of PGI2 biosynthesis, a reduction in the lipopolysaccharide-evoked capacity to produce PGE2 and PGD2, activation of the inflammasome, elevated plasma levels of IL-1β, reduced plasma levels of HDL-C, and a reduction in the capacity for reverse cholesterol transport. By contrast, in the latter, plasma HDL-C and α-tocopherol were elevated, and MIP-1α (macrophage inflammatory protein-1α) and MCP-1 (monocyte chemoattractant protein 1) were reduced.

CONCLUSIONS

Both approaches to Cox-1 deletion similarly restrain thrombogenesis, but a differential impact on Cox-1-dependent prostanoid formation by the vasculature may contribute to an inflammatory phenotype and accelerated atherogenesis in Pf4-ΔCre mice.

Comparative study of venous thromboembolic prophylaxis strategies in hemorrhagic stroke: A systematic review and network meta-analysis

BACKGROUND

Venous thromboembolic events, including deep vein thrombosis (DVT) and pulmonary embolism (PE), are frequent complications in patients with intracerebral hemorrhage (ICH). Various prophylactic strategies have been employed to mitigate this risk, such as heparin, intermittent pneumatic compression (IPC), and graduated compression stockings (GCS). The optimal thromboembolic prophylaxis approach remains uncertain due to the lack of randomized controlled trials (RCTs) comparing all interventions.

AIMS

We conducted a network meta-analysis and meta-analysis to systematically review and synthesize evidence from RCTs and non-randomized studies on the efficacy and safety of thromboembolic prophylaxis strategies in hospitalized ICH patients.

SUMMARY OF FINDINGS

Our study followed a registered protocol (PROSPERO CRD42023489217) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines incorporating the extension for network meta-analyses. Search for eligible studies was performed up to December 2023. We considered the occurrence of DVT, PE, hematoma expansion (HE), and all-cause mortality as outcome measures. A total of 16 studies, including 7 RCTs and 9 non-randomized studies, were included in the analysis. Network meta-analysis revealed that IPC demonstrated the highest efficacy in reducing DVT incidence (odds ratios (OR) 0.30, 95% confidence interval (CI) 0.08-1.16), particularly considering only RCTs (OR 0.33, 95% CI 0.16-0.67). GCS showed the highest safety profile for HE (OR 0.67, 95% CI 0.14-3.13), but without efficacy. Chemoprophylaxis did not reduce the risk of PE events (OR 1.10, 95% CI 0.17-7.19) with a higher occurrence of HE (OR 1.33, 95% CI 0.60-2.96), but the differences were not significant.

CONCLUSION

Our study supports the use of IPC as the primary thromboembolic prophylaxis measure in ICH patients. Further research, including head-to-head RCTs, is needed to strengthen the evidence base and optimize clinical decision-making for thromboembolic prophylaxis in this vulnerable patient population.

Perioperative arterial catheterization: A prospective evaluation of ultrasound, infection, and patient-focused outcomes

BACKGROUND

There is little information regarding complications of arterial catheterization in modern clinical care. We aimed to determine the incidence of abnormal duplex vascular ultrasound and catheter related infections following perioperative arterial catheterization.

METHODS

Patients requiring arterial catheterization for elective surgery were included and insertion details collected prospectively. Duplex ultrasound evaluation was performed 24 h after catheter removal. Symptomatic patients were identified by self-reported questionnaire. On Day 7, patients answered questions by telephone, related to the insertion site, pain, and function. Results of catheter tip and blood culture analyses were sought. Univariate associations of patient and surgical characteristics with abnormal ultrasound were assessed with p < 0.05 considered significant.

RESULTS

Of 339 catheterizations, 105 (40%) had ultrasound evaluation. Catheters were indwelling for median (IQR, range) duration of 6.0 h (4.4-8.2, 1.8-28) with no catheter-related infections. There were 16 (15.2%, 95% CI 9.0%-23.6%) abnormal results, including 14 radial artery thromboses, one radial artery dissection, and one radial vein thrombosis. Those with abnormal ultrasound results were more likely to have had Arrow catheters inserted (68.8% vs 27%, p = 0.023) and more than one skin puncture (37.5% vs 26.8%, p = 0.031). Two of the 16 (12.5%) patients with abnormal ultrasound results reported new symptoms related to the hand compared with nine of the 88 (10.2%) with normal results (p = 0.1). No patients required urgent referral for management.

CONCLUSIONS

Thrombosis was the most common abnormality and was usually asymptomatic. There were no infections, few post-operative symptoms, and minimal functional impairment following arterial catheterization.

H3K4me3-Mediated FOXJ2/SLAMF8 Axis Aggravates Thrombosis and Inflammation in β2GPI/Anti-β2GPI-Treated Monocytes

Antiphospholipid syndrome (APS) is characterized by thrombus formation, poor pregnancy outcomes, and a proinflammatory response. H3K4me3-related monocytes activation are key regulators of APS pathogenesis. Therefore, H3K4me3 CUT&Tag and ATAC-seq are performed to examine the epigenetic profiles. The results indicate that the H3K4me3 signal and chromatin accessibility at the FOXJ2 promoter are enhanced in an in vitro monocyte model by stimulation with β2GPI/anti-β2GPI, which mimics APS, and decreases after OICR-9429 administration. Furthermore, FOXJ2 is highly expressed in patients with primary APS (PAPS) and is the highest in patients with triple-positive antiphospholipid antibodies (aPLs). Mechanistically, FOXJ2 directly binds to the SLAMF8 promoter and activates SLAMF8 transcription. SLAMF8 further interacts with TREM1 to stimulate TLR4/NF-κB signaling and prohibit autophagy. Knockdown of FOXJ2, SLAMF8, or TREM1 blocks TLR4/NF-κB and provokes autophagy, subsequently inhibiting the release of inflammatory and thrombotic indicators. A mouse model of vascular APS is established via β2GPI intraperitoneal injection, and the results suggest that OICR-9429 administration attenuates the inflammatory response and thrombus formation by inactivating FOXJ2/SLAMF8/TREM1 signaling. These findings highlight the overexpression of H3K4me3-mediated FOXJ2 in APS, which consequently accelerates APS pathogenesis by triggering inflammation and thrombosis via boosting the SLAMF8/TREM1 axis. Therefore, OICR-9429 is a promising candidate drug for APS therapy.

COVID-19 associated pulmonary embolism: clinical, biochemical and CT imaging findings

INTRODUCTION

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection represented a disruptive pathology that emerged in late 2019 with profound implications ranging from individual health to health systems and world economy. Our study aimed to evaluate clinical, biochemical and computerized tomography (CT) parameters values in determining the severity of pulmonary embolism (PE) associated with COVID-19.

METHODS

We performed an observational cohort study evaluating demographic, clinical, biochemical, coagulation markers, as well as CT imaging parameters.

RESULTS

In our study on 186 patients with COVID-19, we found that 31 patients (16,66%) had pulmonary embolism. Significant correlations for the patients with PE were detected in C-reactive protein, lactate dehydrogenase, serum ferritin, IL-6, serum myoglobin, NT-proBNP, D-dimers, serum proteins, transaminases as well as white cell blood counts. Patients with pulmonary embolism had a more severe lung involvement, with thrombi distribution mainly involving the lower lobes.

CONCLUSION

Early identification of PE is an important step for timely and efficient treatment in the intensive care management of COVID-19 patients. Our study showed that high plasmatic values of lactate dehydrogenase, ferritin, IL-6, white blood cells and D-dimers and low proteins serum levels are strongly linked with COVID-19-associated pulmonary embolism.

Periodontitis, Dental Procedures, and Young-Onset Cryptogenic Stroke

Periodontitis is associated with an increased risk of ischemic stroke, and the risk may be particularly high among young people with unexplained stroke etiology. Thus, we investigated in a case-control study whether periodontitis or recent invasive dental treatments are associated with young-onset cryptogenic ischemic stroke (CIS). We enrolled participants from a multicenter case-control SECRETO study including adults aged 18 to 49 y presenting with an imaging-positive first-ever CIS and stroke-free age- and sex-matched controls. Thorough clinical and radiographic oral examination was performed. Furthermore, we measured serum lipopolysaccharide (LPS) and lipotechoic acid (LTA) levels. Multivariate conditional regression models were adjusted for stroke risk factors, regular dentist visits, and patent foramen ovale (PFO) status. We enrolled 146 case-control pairs (median age 41.9 y; 58.2% males). Periodontitis was diagnosed in 27.5% of CIS patients and 20.1% of controls (P < 0.001). In the fully adjusted models, CIS was associated with high periodontal inflammation burden (odds ratio [OR], 95% confidence interval) with an OR of 10.48 (3.18-34.5) and severe periodontitis with an OR of 7.48 (1.24-44.9). Stroke severity increased with the severity of periodontitis, having an OR of 6.43 (1.87-23.0) in stage III to IV, grade C. Invasive dental treatments performed within 3 mo prestroke were associated with CIS, with an OR of 2.54 (1.01-6.39). Association between CIS and invasive dental treatments was especially strong among those with PFO showing an OR of 6.26 (1.72-40.2). LPS/LTA did not differ between CIS patients and controls but displayed an increasing trend with periodontitis severity. Periodontitis and recent invasive dental procedures were associated with CIS after controlling for multiple confounders. However, the role of bacteremia as a mediator of this risk was not confirmed.

Sailing in deceptive calm: Navigating the undercurrents of essential thrombocythaemia

The discovery of driver mutations in myeloproliferative neoplasms has significantly contributed to the management of patients with essential thrombocythaemia (ET). High-quality evidence has started to pave the way for targeted therapy. The review by Ferrer-Marín et al. further advances this discussion, highlighting how molecular profiling, including non-driver gene mutations, is set to revolutionize personalized treatment approaches for ET patients. Commentary on: Ferrer-Marín et al. Essential thrombocythemia: a contemporary approach with new drugs on the horizon. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19403.

Hormonal Contraception and Menstrual Cycle Control at High Altitude: A Scoping Review-UIAA Medical Commission Recommendations

Horakova, Lenka , Susi Kriemler, Vladimír Študent, Jacqueline Pichler Hefti, David Hillebrandt, Dominique Jean, Kastė Mateikaitė-Pipirienė, Peter Paal, Alison Rosier, Marija Andjelkovic, Beth Beidlemann, Mia Derstine, and Linda E. Keyes. Hormonal contraception and menstrual cycle control at high altitude: a scoping review-UIAA Medical Commission recommendations. High Alt Med Biol. 00:00-00, 2024. Background: Women who use hormonal contraception (HC) may have questions about their use during travel to high altitude. This scoping review summarizes current evidence on the efficacy and safety of HC and cycle control during high-altitude travel. Methods: We performed a scoping review for the International Climbing and Mountaineering Federation (UIAA) Medical Commission series on Women's Health in the Mountains. Pertinent literature from PubMed and Cochrane was identified by keyword search combinations (including contraception) with additional publications found by hand search. Results: We identified 17 studies from 7,165 potentially eligible articles. No articles assessed the efficacy of contraception during a short-term high-altitude sojourn. Current data show no advantage or disadvantage in HC users for acclimatization or acute mountain sickness (AMS). Use of HC during high-altitude travel is common and safe for menses suppression. A potential concern of estrogen-containing HC is the increased thrombotic risk, which theoretically could be compounded in hypobaric hypoxia. Conclusions: Evidence is limited for the interaction of HC and high altitude on performance, thrombosis, and contraceptive efficacy. HC does not affect the risk of AMS. The most efficacious and safest method at high altitude is generally the one women are most familiar with and already using.

Protein disulfide isomerase cleaves allosteric disulfides in histidine-rich glycoprotein to regulate thrombosis

The essence of difference between hemostasis and thrombosis is that the clotting reaction is a highly fine-tuned process. Vascular protein disulfide isomerase (PDI) represents a critical mechanism regulating the functions of hemostatic proteins. Herein we show that histidine-rich glycoprotein (HRG) is a substrate of PDI. Reduction of HRG by PDI enhances the procoagulant and anticoagulant activities of HRG by neutralization of endothelial heparan sulfate (HS) and inhibition of factor XII (FXIIa) activity, respectively. Murine HRG deficiency (Hrg-/-) leads to delayed onset but enhanced formation of thrombus compared to WT. However, in the combined FXII deficiency (F12-/-) and HRG deficiency (by siRNA or Hrg-/-), there is further thrombosis reduction compared to F12-/- alone, confirming HRG's procoagulant activity independent of FXIIa. Mutation of target disulfides of PDI leads to a gain-of-function mutant of HRG that promotes its activities during coagulation. Thus, PDI-HRG pathway fine-tunes thrombosis by promoting its rapid initiation via neutralization of HS and preventing excessive propagation via inhibition of FXIIa.

Pitfalls of ultrasound for deep vein thrombosis of the lower extremities

Venous ultrasound is the primary, widely accepted diagnostic tool to assess deep vein thrombosis (DVT) in the lower extremities. However, other focal lesions in the lower extremities can be identified on ultrasound. The sonographic appearance of these abnormalities may overlap the thrombosis, which included vascular tumors, Baker's cyst, hematoma, cancer thrombosis, and peripheral nerve tumors. This essay derives from cases diagnosed in our centers and published literature, with images available for illustrations, which may help to improve the clinical management of these findings.

Laboratory approach for vaccine-induced thrombotic thrombocytopenia diagnosis in the Netherlands

BACKGROUND AND OBJECTIVES

Vaccine-induced thrombotic thrombocytopenia (VITT) is a rare adverse effect characterized by thrombocytopenia and thrombosis occurring after COVID-19 vaccination. VITT pathophysiology is not fully unravelled but shows similarities to heparin-induced thrombocytopenia (HIT). HIT is characterized by the presence of antibodies against platelet factor 4 (PF4)/heparin complex, which can activate platelets in an FcγRIIa-dependent manner, whereas IgG-antibodies directed against PF4 play an important role in VITT.

MATERIALS AND METHODS

We characterized all clinically suspected VITT cases in the Netherlands from a diagnostic perspective and hypothesized that patients who developed both thrombocytopenia and thrombosis display underlying mechanisms similar to those in HIT. We conducted an anti-PF4 ELISA and a functional PF4-induced platelet activation assay (PIPAA) with and without blocking the platelet-FcγRIIa and found positivity in both tests, suggesting VITT with mechanisms similar to those in VITT.

RESULTS

We identified 65 patients with both thrombocytopenia and thrombosis among 275 clinically suspected VITT cases. Of these 65 patients, 14 (22%) tested positive for anti-PF4 and PF4-dependent platelet activation. The essential role of platelet-FcγRIIa in VITT with mechanisms similar to those in HIT was evident, as platelet activation was inhibited by an FcγRIIa-blocking antibody in all 14 patients.

CONCLUSION

Our study shows that only a small proportion of clinically suspected VITT patients with thrombocytopenia and thrombosis have anti-PF4-inducing, FcɣRIIa-dependent platelet activation, suggesting an HIT-like pathophysiology. This leaves the possibility for the presence of another type of pathophysiology ('non-HIT like') leading to VITT. More research on pathophysiology is warranted to improve the diagnostic algorithm and to identify novel therapeutic and preventive strategies.

Reducing the global burden of cerebral venous thrombosis: An international research agenda

BACKGROUND

Due to the rarity of cerebral venous thrombosis (CVT), performing high-quality scientific research in this field is challenging. Providing answers to unresolved research questions will improve prevention, diagnosis, and treatment, and ultimately translate to a better outcome of patients with CVT. We present an international research agenda, in which the most important research questions in the field of CVT are prioritized.

AIMS

This research agenda has three distinct goals: (1) to provide inspiration and focus to research on CVT for the coming years, (2) to reinforce international collaboration, and (3) to facilitate the acquisition of research funding.

SUMMARY OF REVIEW

This international research agenda is the result of a research summit organized by the International Cerebral Venous Thrombosis Consortium in Amsterdam, the Netherlands, in June 2023. The summit brought together 45 participants from 15 countries including clinical researchers from various disciplines, patients who previously suffered from CVT, and delegates from industry and non-profit funding organizations. The research agenda is categorized into six pre-specified themes: (1) epidemiology and clinical features, (2) life after CVT, (3) neuroimaging and diagnosis, (4) pathophysiology, (5) medical treatment, and (6) endovascular treatment. For each theme, we present two to four research questions, followed by a brief substantiation per question. The research questions were prioritized by the participants of the summit through consensus discussion.

CONCLUSIONS

This international research agenda provides an overview of the most burning research questions on CVT. Answering these questions will advance our understanding and management of CVT, which will ultimately lead to improved outcomes for CVT patients worldwide.

Primary catastrophic antiphospholipid syndrome in children with midbrain infarction: a case report

Background

Catastrophic antiphospholipid syndrome (CAPS) is a multi-system autoimmune disease characterized by extensive thrombosis. Pediatric CAPS is extremely rare and associated with a high mortality rate, especially when midbrain infarction is involved. Hence, early diagnosis and prompt initiation of appropriate treatment for CAPS complicated by midbrain infarction are of utmost importance in achieving favorable outcomes.

Case presentation

In this report, we present the case of a 14-year-old girl who presented with neurological symptoms and digestive system infection and was initially diagnosed with an "intracranial infection". After a series of rigorous diagnostic procedures, the patient was ultimately diagnosed with primary CAPS and was immediately transferred to the intensive care unit where she was treated with anticoagulation, glucocorticoids, intravenous immunoglobulin (IVIG) therapy, and multiple plasma infusions. Twenty-seven days after admission, the patient's condition improved with standardized treatment, and she was discharged and followed up regularly.

Conclusion

This case report provides a description of the clinical features observed in a pediatric patient with CAPS and concurrent midbrain infarction, highlighting the crucial role of early diagnosis and timely treatment in influencing patient prognosis.

Coagulation activity and thrombotic risk following high-volume endurance exercise in recreationally active cyclists

Despite the prognostic effect of physical activity, acute bouts of high-volume endurance exercise can induce cardiac stress and post-exercise hypercoagulation associated with increased thrombotic risk. The aim of this study was to explore the effect of high-volume endurance exercise on coagulation and thrombotic activity in recreational cyclists. Thirty-four recreational cyclists completed 4.8 ± 0.3 hours cycling at 45 ± 5% of maximal power output on a bicycle ergometer. Intravenous blood samples were collected pre-exercise, immediately post-exercise, 24 and 48 hours post-exercise and analysed for brain natriuretic peptide (BNP), cardiac troponin (cTn), C-reactive protein (CRP), D-dimer, thrombin-antithrombin (TAT) complex, tissue factor (TF), tissue factor pathway inhibitor (TFPI) and TF to TFPI ratio (TF:TFPI). An increase in cTn was observed post-exercise (p < 0.001). CRP concentrations were increased at 24 and 48 hours post-exercise compared to pre-exercise concentrations (p ≤ 0.001). TF was elevated at 24 hours post-exercise (p < 0.031) and TFPI was higher immediately post-exercise (p < 0.044) compared to all other time points. TF:TFPI was increased at 24 and 48 hours post-exercise compared to pre-exercise (p < 0.025). TAT complex was reduced at 48 hours post-exercise compared to pre-exercise (p = 0.015), D-dimer was higher immediately post-exercise compared to all other time points (p ≤ 0.013). No significant differences were observed in BNP (p > 0.05). High-volume endurance cycling induced markers of cardiac stress among recreational cyclists. However, plasma coagulation and fibrinolytic activity suggests no increase in thrombotic risk after high-volume endurance exercise.

Glycoursodeoxycholic Acid Alleviates Arterial Thrombosis via Suppressing Diacylglycerol Kinases Activity in Platelet

BACKGROUND

Glycoursodeoxycholic acid (GUDCA) has been acknowledged for its ability to regulate lipid homeostasis and provide benefits for various metabolic disorders. However, the impact of GUDCA on arterial thrombotic events remains unexplored. The objective of this study is to examine the effects of GUDCA on thrombogenesis and elucidate its underlying mechanisms.

METHODS

Plasma samples from patients with arterial thrombotic events and diet-induced obese mice were collected to determine the GUDCA concentrations using mass spectrometry. Multiple in vivo murine thrombosis models and in vitro platelet functional assays were conducted to comprehensively evaluate the antithrombotic effects of GUDCA. Moreover, lipidomic analysis was performed to identify the alterations of intraplatelet lipid components following GUDCA treatment.

RESULTS

Plasma GUDCA level was significantly decreased in patients with arterial thrombotic events and negatively correlated with thrombotic propensity in diet-induced obese mice. GUDCA exhibited prominent suppressing effects on platelet reactivity as evidenced by the attenuation of platelet activation, secretion, aggregation, spreading, and retraction (P<0.05). In vivo, GUDCA administration robustly alleviated thrombogenesis (P<0.05) without affecting hemostasis. Mechanistically, GUDCA inhibited DGK (diacylglycerol kinase) activity, leading to the downregulation of the phosphatidic acid-mediated signaling pathway. Conversely, phosphatidic acid supplementation was sufficient to abolish the antithrombotic effects of GUDCA. More importantly, long-term oral administration of GUDCA normalized the enhanced DGK activity, thereby remarkably alleviating the platelet hyperreactivity as well as the heightened thrombotic tendency in diet-induced obese mice (P<0.05).

CONCLUSIONS

Our study implicated that GUDCA reduces platelet hyperreactivity and improves thrombotic propensity by inhibiting DGKs activity, which is a potentially effective prophylactic approach and promising therapeutic agent for arterial thrombotic events.

Managing venous thrombosis in a pediatric patient with short bowel and congenital nephrotic syndromes: a case report emphasizing rivaroxaban level monitoring

Direct Oral Anticoagulants (DOACs) typically exhibit a predictable pharmacokinetic and pharmacodynamic response at a fixed dose, not necessitating monitoring under standard conditions. Yet, in specific clinical scenarios that can impair it, like Congenital Nephrotic Syndrome (CNS) or Short Bowel Syndrome (SBS) due to absorption issues, anti-thrombin III (AT-III) deficiency and non-selective proteinuria, adjusting the dosage to achieve appropriate plasma concentrations could prove beneficial. We report a 3-month-old female with catheter-related jugular thrombosis affected by CNS concomitant to SBS and failure of both treatments with heparin and warfarin, that was switched to dose-adjusted pediatric rivaroxaban. Rivaroxaban was adjusted to reach peak levels between 189 and 419 ng/ml and the lower trough levels between 6 and 87 ng/ml. Increasing doses were needed due to SBS related malabsorption but a complete permeabilization of the vein was achieved without bleeding complications. The use of anti-Xa adjusted rivaroxaban could be an alternative to improve anticoagulation and secondary thromboprophylaxis in pediatric patients SBS and an option to children with CNS.

Nutrition and Cardiovascular Disease: The Potential Role of Marine Bioactive Proteins and Peptides in Thrombosis Prevention

Thrombus and cardiovascular diseases pose a significant health threat, and dietary interventions have shown promising potential in reducing the incidence of these diseases. Marine bioactive proteins and peptides have been extensively studied for their antithrombotic properties. They can inhibit platelet activation and aggregation by binding to key receptors on the platelet surface. Additionally, they can competitively anchor to critical enzyme sites, leading to the inhibition of coagulation factors. Marine microorganisms also offer alternative sources for the development of novel fibrinolytic proteins, which can help dissolve blood clots. The advancements in technologies, such as targeted hydrolysis, specific purification, and encapsulation, have provided a solid foundation for the industrialization of bioactive peptides. These techniques enable precise control over the production and delivery of bioactive peptides, enhancing their efficacy and safety. However, it is important to note that further research and clinical studies are needed to fully understand the mechanisms of action and therapeutic potential of marine bioactive proteins and peptides in mitigating thrombotic events. The challenges and future application perspectives of these bioactive peptides also need to be explored.

Results and prognosis of kidney transplantation in lupus nephritis: Experience of an Argentine center

INTRODUCTION

Although RT has improved the survival of the population with ESRD due to all causes, renal outcomes in SLE are controversial. The objective of this study is to describe the characteristics and evolution of the patients and the kidney transplant in LN, and compare it with patients transplanted for other causes.

MATERIALS AND METHODS

Retrospective, observational, analytical, single-center study in which records of patients undergoing nephrotransplantation for LN were analyzed. They were compared with a group of patients transplanted at the same center for other causes of ESRD.

RESULTS

41 patients with kidney transplant due to SLE and 89 transplanted due to other causes of ESRD were registered. Graft loss occurred in 12 (29.26%) patients with LN and 34 (38.2%) patients in the comparison group (p = .428). Only one case (4.8%) presented reactivation of the LN in the graft, without graft loss. Median graft survival was 73.1 months in the LN group and 66.3 months in the comparison group (p = .221). A total of 8 (19.5%) patients with LN and 11 (12.4%) without LN died (p = .42), with infections being the main cause in both groups. There were no statistically significant differences between groups in graft and patient survival. In a sub-analysis of 28 patients with LN with aPL study, 4 thrombotic events were observed, in 3 different patients, in the aPL-positive group. There were no statistically significant differences in terms of causes of graft loss and graft survival (positive aFL 75.7 months vs negative aFL 72.7 months, p= .96). There were also no differences in mortality between the groups (p = .61).

CONCLUSION

Patients transplanted for LN did not differ from the control population in terms of graft and patient survival. Infections were the main cause of death, so prophylaxis and vaccination continue to be a fundamental pillar in the prevention of infections in immunocompromised patients.

Patients with antiphospholipid syndrome and a first venous or arterial thrombotic event: clinical characteristics, antibody profiles and estimate of the risk of recurrence

OBJECTIVES

Thrombosis in antiphospholipid syndrome (APS) involves in most cases the venous circulation. Why in some patients thrombotic APS affects the arterial circulation and in particular cerebral circulation is unknown. In previous studies, both patient characteristics and antiphospholipid antibody types and titers have been associated with arterial thrombosis. Aim of this study was to compare the clinical characteristics and laboratory findings of venous and arterial thrombotic APS from a large series of patients.

METHODS

Data were retrieved from the Start 2 antiphospholipid, a multicenter prospective register of long-term collected data from Thrombosis Centers in Italy.

RESULTS

Of 167 patients with thrombotic APS, 114 (68 %) had a venous and 53 (32 %) had an arterial event as first clinical manifestation. Several clinical characteristics and risk factors were different among groups in univariate analysis. Using logistic regression analysis, reduced creatinine clearance and hyperlipidemia were independent variable for the occurrence of arterial APS. Notably, no difference in antiphospholipid antibody profiles and aβ2-Glycoprotein I levels were found between groups. A higher adjusted global antiphospholipid syndrome score (aGAPSS) was found in arterial group indicating a possible high recurrence rate in arterial APS.

CONCLUSIONS

These data have pathophysiological and clinical implication since associated conditions might predispose patients to arterial rather than venous events and call to a close monitoring and treatment of arterial APS due to their increased tendency to recurrence.

The impact of Libman-sacks endocarditis on inpatient outcomes with systemic lupus erythematosus: A retrospective study

INTRODUCTION

The existing literature offers limited insights into the influence of Libman-Sacks Endocarditis (LSE) on inpatient outcomes in individuals with Systemic Lupus Erythematosus (SLE). This study aimed to explore the characteristics and prognosis of SLE patients with LSE and the impact of LSE in patients with SLE on inpatient outcomes including inpatient mortality, length of stay, acute heart failure, atrial fibrillation, and cerebrovascular accidents (CVA).

METHODS

This study included adult patients who were hospitalized with SLE between the years 2019 and 2020, using the National Inpatient Sample (NIS) database. The total number of patients with a diagnosis of SLE in the years 2019 and 2020 in the NIS database was 150,411. Of those, 349 had a diagnosis of LSE. The study population was divided into two groups: one group with SLE and LSE, and another group with SLE but without LSE.

RESULTS

Caucasians made up 54.9% of the patients with a diagnosis of SLE in our patient population, while African Americans made up 26.9% and the Hispanics accounted for 12.2%. Of patients with LSE, Caucasians and African Americans represented 42.9% each. Patients with a diagnosis of LSE had a higher inpatient mortality than those with SLE without LSE (aOR: 9.74 CI 1.12-84.79, p 0.04). Patients with SLE with LSE were more likely to have acute heart failure than those without LSE, although this was not statistically significant (aOR 1.18 CI 0.13-11.07, p 0.88). Similarly, patients with SLE with LSE were more likely to have atrial fibrillation than those without LSE (aOR 4.45 CI: 0.77-25.57, p 0.10). CVAs were significantly higher in SLE patients with LSE than those without LSE (aOR 141.43 CI 16.59-1205.52, p < .01).

DISCUSSION

Patients who develop LSE were found to have significantly higher risks of inpatient mortality and cerebrovascular accidents. Early and precise detection of LSE in such patients may ensure timely intervention and prevention of the associated adverse outcomes. Further studies may attempt to develop screening methods for detection of LSE to effectively reduce morbidity and mortality associated with SLE.

Recovery and partial purification of fibrinolytic protease from Pleurotus ostreatus and P. eryngii and cytotoxic and antioxidant activity of their extracts

Mushrooms are a source of primary and secondary metabolites. Little is known about the most suitable conditions for production of mushrooms by submerged fermentation. This article reports antioxidant and cytotoxic assays, in addition to quantitatively evaluating the content of proteases with fibrinolytic action in the crude extracts of two species of edible mushrooms produced in different formulations, as well as evaluating the recovery of these enzymes by aqueous two-phase systems (ATPS). The mushrooms Pleurotus ostreatus and Pleurotus eryngii, at concentration of 100 µg/mL, displayed inhibition of DPPH and ABTS radicals below 50%. In the cytotoxicity test, the cells human fibroblast cell lines (MRC-5) showed cell viability greater than 80%. Concerning fibrinolytic activity, P. eryngii presented 226.47 ± 7.26 U/mL, therefore being more efficient than P. ostreatus (71.5 ± 0.56 U/mL). In the recovery of the P. eryngii extract by ATPS, the fibrinolytic protease was partitioned in the salt phase (30.25 U/mL). The molecular mass of the proteases was between 75 and 100 kDa. These results prove the low cytotoxicity of the extracts produced and that fermentation in supplemented malt broth favored the excretion of fibrinolytic proteases compared to the other evaluated media.

Septal atrial thrombosis as a primary presentation of antiphospholipid syndrome in a patient with ANA-negative systemic lupus erythematosus: a case report

Introduction and importance

Systemic lupus erythematosus (SLE) predominantly affects young women and is associated with an increased risk of thrombosis. Antiphospholipid antibody syndrome (APS) may complicate the clinical picture, often leading to recurrent arteriovenous thrombosis. This case report underscores the significance of two unique aspects: the rare occurrence of an atrial thrombus and the presence of antinuclear antibody (ANA)-negative SLE.

Case presentation

A 32-year-old woman presented with a history of symmetric polyarticular joint pain, oral ulcers, significant weight loss, and a history of unprovoked popliteal thrombosis and two unexplained abortions. One week prior to admission, she experienced severe headaches and elevated blood pressure. Clinical evaluation revealed several abnormalities, including a systolic murmur, livedo reticularis, and a transthoracic echocardiogram showing severe mitral regurgitation and an atrial thrombus. A transesophageal echocardiogram confirmed the presence of a pedunculated lesion in the right atria, challenging differential diagnosis.

Clinical discussion

ANA-negative SLE, though rare, was observed in this patient, highlighting diagnostic complexities. APS compounded the clinical presentation, emphasizing the importance of identifying specific autoantibodies and recurrent thrombotic events. In the case of atrial thrombus, differentiation from other cardiac conditions, such as myxoma or vegetation, is a key.

Conclusions

This case underscores the critical importance of recognizing and managing atrial thrombus, a rare but life-threatening complication in patients with systemic lupus erythematosus and antiphospholipid syndrome. Additionally, the diagnostic challenge of ANA-negative SLE warrants careful consideration in patients presenting with characteristic features of the disease.

Combination Anticoagulation Strategy in Pregnancy With Mechanical Valves: The KYBELE Study

BACKGROUND

Optimal first-trimester anticoagulation is still challenging in pregnant women with mechanical heart valves (MHVs) requiring high-dose warfarin.This multicenter prospective study aims to determine the optimal anticoagulation regimens for pregnant patients with MHVs.

METHODS

All women were allocated to one of three treatment options during first trimester including lone low-molecular-weight heparin (LMWH), combination of LMWH+2.5 mg warfarin, and LMWH+4 mg warfarin. Primary maternal outcome included a combination of death, thromboembolism, severe bleeding, and need for treatment of mechanical valve thrombosis (MVT).Any fetal loss was determined as primary fetal outcome.

RESULTS

The study included 78 pregnancies in 65 women with MHVs.Primary maternal outcome rate was 44%, 12.5%, 3.5%, respectively.The rates of primary maternal outcome (44 vs 3.5%, p<0.001), obstructive MVT (16 vs 0%, p=0.04), MVT requiring treatment (28 vs 0%, p=0.003), and cerebral embolism (24 vs 3.4%, p=0.041) were found to be significantly higher in lone LMWH group compared to LMWH+4 mg warfarin group. Moreover, the rates of primary maternal outcome (12.5 vs 44%, p=0.015) and treatment for MHV thrombus (4.2 vs 28%, p=0.049) were significantly lower in LMWH+2.5 mg warfarin group compared to lone LMWH group.The incidences of fetal loss were 8 (32%) in the lone LMWH group, 8 (33.3%) in LMWH+2.5 mg warfarin group, and 11 (37.9%) in LMWH+4 mg warfarin group (p=0.890 for 3-group).Warfarin related-embryopathy was not observed in any case.

CONCLUSIONS

The combined anticoagulation strategy of LMWH plus low-dose warfarin during the first trimester of pregnancy may result in less maternal complications with comparable fetal outcomes in patients with MHVs.

CONDENSED ABSTRACT

Low-molecular-weight heparin (LMWH) is thought to be safer for the fetus, however it is suspected to be less protective for the mother. To solve this dilemma, the authors suggested a novel anticoagulation strategy in pregnant women with prosthetic valves. Seventy-eight pregnancies of 65 women [median age 32 (27-35) years] were included in the study. A combination of LMWH and a reduced dose warfarin were associated with low rates of thrombus-related complications in pregnant patients with mechanical heart valves.

Evaluation of enoxaparin for bridging of warfarin in outpatients with left ventricular assist devices (LVADs)

BACKGROUND

Patients with left ventricular assist devices (LVADs) require systemic anticoagulation. The use of enoxaparin for bridging to warfarin remains understudied in this population.

METHODS

This single-center retrospective study was performed to characterize enoxaparin use and associated thrombotic and bleeding outcomes in adult outpatients with LVADs from January 2018 to July 2021.

RESULTS

Fifty-four enoxaparin bridging events were evaluated in 49 patients. Most patients with HeartMate II (HM2) and HeartWare (HVAD) devices received enoxaparin dosed 1 mg/kg every 12 h. In patients with HeartMate 3 (HM3) devices, an equal number of patients received 0.5 mg/kg every 12 h and 1 mg/kg every 12 h, with a smaller subset receiving intermediate doses. The median duration of bridging was 6 days (4-8 [IQR]). One major bleeding event required discontinuation of enoxaparin and hospitalization in a patient with an HM3 device. Thrombotic events occurred in four patients with two incidents of pump thrombosis requiring pump exchange and two ischemic strokes. All thrombotic events occurred in patients with HVAD or HM2 devices.

CONCLUSION

These results suggest that enoxaparin bridging in LVAD patients was well-tolerated with low bleeding and thrombotic rates, particularly with the HM3 device.

Primary antiphospholipid syndrome in a male presents with acute digital ischemia: Dramatic response to glucocorticoid

We present a rare case of primary antiphospholipid syndrome in a 38-year-old male who presented with painful digital ischemia. Early initiation of anticoagulation and addition of glucocorticoid led to a significant improvement in the patient.

Association of the neutrophil-to-lymphocyte ratio with the occurrence of venous thromboembolism and arterial thrombosis

OBJECTIVE

This study aimed to assess the association of the neutrophil-to-lymphocyte ratio (NLR) with the occurrence of venous thromboembolism (VTE) and arterial thrombosis (AT).

METHODS

This was a retrospective cross-sectional study including 585 medical records obtained from all consecutive patients who were suspected of having thrombosis.

RESULTS

The AT group had a higher neutrophil count and NLR and a lower lymphocyte count than the non-thrombosis group. Receiver operating characteristic curve analysis showed the ability of the NLR to predict the presence of AT. The cut-off value for the NLR was 4.44. No distinction was found in the NLR between the VTE and non-thrombosis groups. Regression analysis showed that a high NLR was an independent factor related to the presence of AT. Patients with an NLR ≥ 4.44 had a higher risk of AT than those with an NLR < 4.44 (odds ratio = 2.015, 95% confidence interval: 1.180-3.443).

CONCLUSION

A high NLR may be considered a predictive factor for the occurrence of AT, but an association with the presence of VTE was not found.

Skin erythematous migrant lesions consistent with histologically confirmed dermal arteriolar thrombosis connected to APS

Antiphospholipid syndrome (APS) is an acquired thrombophilic disorder related to the presence of antiphospholipid antibodies (LAC, anticardiolipin, anti Beta2-glycoprotein) known to cause venous and arterial thrombosis and recurrent pregnancy loss. Skin disorder is a frequent finding usually due to vascular thrombosis involving the dermal layer and can be either localized or widespread causing necrosis and ulceration of the skin, without histological evidence of vasculitis. We present a case of a woman with APS with both arterial and venous thrombotic involvement associated with an atypical dermatological manifestation histologically consistent with a pauci-inflammatory intermediate-deep dermal arteriolar platelet-mediated thrombosis that appeared despite anticoagulation with warfarin and responding to the addition of antiplatelet therapy.

Role of factor XIII in ischemic stroke: a key molecule promoting thrombus stabilization and resistance to lysis

BACKGROUND

Active coagulation factor XIII (FXIII) catalyzing crosslinking of fibrin and other hemostatic factors plays a key role in clot stability and lysis.

OBJECTIVES

To evaluate the effect of FXIII inhibition in a mouse model of ischemic stroke (IS) and the role of activated FXIII (FXIIIa) in clot formation and lysis in patients with IS.

METHODS

A ferric chloride IS murine model was performed before and after administration of a FXIIIa inhibitor (FXIIIinh). Thromboelastometry in human and mice blood was used to evaluate thrombus stiffness and lysis with FXIIIinh. FXIIIa-dependent fibrin crosslinking and lysis with fibrinolytic drugs (tissue plasminogen activator and tenecteplase) were studied on fibrin plates and on thrombi and clotted plasma of patients with IS. Finally, circulating and thrombus FXIIIa were measured in 85 patients with IS.

RESULTS

FXIIIinh administration before stroke induction reduced infarct size, α2-antiplasmin (α2AP) crosslinking, and local microthrombosis, improving motor coordination and fibrinolysis without intracranial bleeds (24 hours). Interestingly, FXIII blockade after stroke also reduced brain damage and neurologic deficit. Thromboelastometry in human/mice blood with FXIIIinh showed delayed clot formation, reduced clot firmness, and shortened tissue plasminogen activator lysis time. FXIIIa fibrin crosslinking increased fibrin density and lysis resistance, which increased further after α2AP addition. FXIIIinh enhanced ex vivo lysis in stroke thrombi and fibrin plates. In patients with IS, thrombus FXIII and α2AP were associated with inflammatory and hemostatic components, and plasma FXIIIa correlated with thrombus α2AP and fibrin.

CONCLUSION

Our results suggest a key role of FXIIIa in thrombus stabilization, α2AP crosslinking, and lysis resistance, with a protective effect of FXIIIinh in an IS experimental model.

Short, frequent, light-intensity walking activity improves postprandial vascular-inflammatory biomarkers in people with type 1 diabetes: The SIT-LESS randomized controlled trial

AIM

To examine the effect of interrupting prolonged sitting with short, frequent, light-intensity activity on postprandial cardiovascular markers in people with type 1 diabetes (T1D).

MATERIALS AND METHODS

In a randomized crossover trial, 32 adults with T1D (mean ± SD age 28 ± 5 years, glycated haemoglobin 67.9 ± 12.6 mmol/mol, 17 women) completed two 7-h laboratory visits separated by >7 days. Participants either remained seated for 7 h (SIT) or interrupted sitting with 3-min bouts of self-paced walking at 30-min intervals commencing 1 h after each meal (SIT-LESS). Physical activity, insulin regimen, experimental start times, and meal consumption were standardized during each arm. Plasma levels of interleukin (IL)-1β, tumour necrosis factor (TNF)-α, plasminogen activator inhibitor (PAI)-1 and fibrinogen were sampled at baseline, 3.5 and 7 h, and assessed for within- and between-group effects using a repeated measures ANOVA. The estimated glucose disposal rate was used to determine the insulin resistance status.

RESULTS

Vascular-inflammatory parameters were comparable between SIT and SIT-LESS at baseline (p > .05). TNF-α, IL-1β, PAI-1 and fibrinogen increased over time under SIT, whereas these rises were attenuated under SIT-LESS (p < .001). Specifically, over the 7 h under SIT, postprandial increases were detected in TNF-α, IL-1β, PAI-1 and fibrinogen (+67%, +49%, +49% and +62%, respectively; p < .001 for all). Conversely, the SIT-LESS group showed no change in IL-1β (-9%; p > .50), whereas reductions were observed in TNF-α, PAI-1 and fibrinogen (-22%, -42% and -44%, respectively; p < .001 for all). The intervention showed enhanced effects in insulin-resistant individuals with T1D.

CONCLUSIONS

Interrupting prolonged sitting with light-intensity activity ameliorates postprandial increases in vascular-inflammatory markers in T1D.

TRIAL REGISTRATION

The trial was prospectively registered (ISRCTN13641847).

Renal vein thrombosis in a patient secondary to high-grade rhabdoid renal cell carcinoma: a case report and review of literature

Introduction

Renal cell carcinoma, a common kidney tumour which is often incidentally discovered on imaging, can manifest with atypical symptoms. Renal cell carcinoma with rhabdoid features is a rare occurrence and even rarer in case of adults. Renal cell carcinoma has the tendency to form thrombus that can migrate to renal vein, inferior vena cava and even right atrium.

Case presentation

The authors report a case of an 81-year-old male with rhabdoid renal cell carcinoma presenting with persistent cough for 6-7 months. with tumour thrombus extending into the renal vein and hepatic inferior vena cava. The patient was found feeble for the surgery and hence was treated on anticancer drugs pembrolizumab and axitinib.

Conclusion

Renal cell carcinoma has the tendency to form tumour thrombus in renal vein and inferior vena cava. Prognosis without surgical intervention in these conditions is very poor.

Outcomes of heparinized adult veno-arterial extracorporeal membrane oxygenation patients managed with low and high activated partial thromboplastin time targets: A systematic review and meta-analysis

INTRODUCTION

There are no randomized controlled trials comparing low and high activated partial thromboplastin time (aPTT) targets in heparinized adult veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) patients. Our systematic review and meta-analysis summarized complication rates in adult VA ECMO patients treated with low and high aPTT targets.

METHODS

Studies published from January 2000 to May 2022 were identified using Pubmed, Embase, Cochrane Library, and LILACS (Latin American and Caribbean Health Sciences Literature). Studies were included if aPTT was primarily used to guide heparin anticoagulation. For the low aPTT group, we included studies where aPTT goal was ≤60 seconds and for the high aPTT group, we included studies where aPTT goal was ≥60 seconds. Proportional meta-analysis with a random effects model was used to calculate pooled complication rates for patients in the two aPTT groups.

RESULTS

Twelve studies met inclusion criteria (5 in the low aPTT group and 7 in the high aPTT group). The pooled bleeding complication incidence for low aPTT studies was 53.6% (95% CI = 37.4%-69.4%, I2 = 60.8%) and for high aPTT studies was 43.8% (95% CI = 21.7%-67.1%, I2 = 91.8%). No studies in the low aPTT group reported overall thrombosis incidence, while three studies in the high aPTT group reported overall thrombosis incidence. The pooled thrombosis incidence for high aPTT studies was 16.1% (95% CI = 9.0%-24.5%, I2 = 13.1%).

CONCLUSIONS

Adult ECMO patients managed with low and high aPTT goals appeared to have similar bleeding and other complication rates further highlighting the need for a randomized controlled trial.

Successful thrombolysis of early bioprosthetic mitral valve thrombosis following extracorporeal membrane oxygenation: Case report

Introduction: Bioprosthetic mitral valve thrombosis (BPMVT) following post-operative extracorporeal membrane oxygenation (ECMO) is a rare complication with high mortality.Case Report: A 75-year-old man with a flail posterior mitral leaflet underwent a bioprosthetic mitral valve replacement and was subsequently placed on central veno-arterial high flow ECMO following intractable shock after protamine administration. He developed BPMVT over the following 48 hr, which did not resolve with 3 weeks of systemic heparin. He was then treated successfully with 3 days of continuous low dose (1 mg/hr) Tissue Plasminogen Activator (TPA). He suffered no bleeding consequences and had a complete cardiac and end-organ recovery.Discussion: Slow TPA infusion may be an acceptable treatment strategy for alleviating thrombotic burden from a bioprosthetic valve, even in the post-operative setting.

Right disc thrombosis of the new Gore Cardioform ASD Occluder

BACKGROUND

The GCA is a well performing device in terms of efficacy despite complex anatomies (aortic rim <5 mm and ASD diameter >17 mm) with a good safety profile.

AIMS

To evaluate atrial septal defect (ASD) features impacting on right disc device thrombosis in patients who underwent Gore Cardioform ASD Occluder (GCA) implantation.

METHODS

A total of 44 consecutive patients undergoing percutaneous ASD with GCA device from January 2020 to September 2022 at our tertiary care Center were evaluated. The minimum follow-up was 6 months.

RESULTS

The patients were stratified in two groups according to a cut-off value of ASD diameter equal to 20 mm at sizing balloon, derived from ROC analysis (AUC = 0.894; p = 0.024). Baseline characteristics were comparable between groups in terms of age, sex, weight, height, and interatrial septum dimensions. Patients with ASD > 20 mm (n = 9) had a higher ASD/device dimension ratio, both at echocardiography (p = 0.009) and at sizing balloon (p = 0.001), longer fluoroscopic time (p = 0.022), and higher incidence of device thrombosis (0.006). Right disc thrombosis was observed in three patients of the ASD > 20 mm group, always in the inferior portion of the right disc. On univariate analysis, ASD diameter at sizing balloon (OR 1.360; p = 0.036) was the only positive predictor of device thrombosis.

CONCLUSIONS

Right disc thrombosis of the GCA device may be under-recognized at follow-up, hence deserving clinical attention, especially in those patients with larger ASD diameters.

Comparison of bleeding and thrombotic outcomes in veno-venous extracorporeal membrane oxygenation: Heparin versus bivalirudin

OBJECTIVES

We aimed to evaluate thrombotic and hemorrhagic complications with heparin versus bivalirudin use in veno-venous extracorporeal membrane oxygenation (V-V ECMO).

METHODS

We performed a retrospective cohort study of adult patients placed on V-V ECMO with intravenous anticoagulation with either heparin or bivalirudin. Time to thrombotic event and major bleed were analyzed in addition to related outcomes.

RESULTS

We identified 95 patients placed on V-V ECMO: 61 receiving heparin, 34 bivalirudin. The bivalirudin group had a higher rate of severe COVID-19, higher BMI, and longer ECMO duration. Despite this, bivalirudin was associated with reduced risk of thrombotic event (HR 0.14, 95% CI 0.06-0.32, p < .001) and increased average lifespan of the circuit membrane lung (16 vs. 10 days, p = 0.004). While there was no difference in major bleeding, the bivalirudin group required fewer transfusions of packed red blood cells and platelets per 100 ECMO days (means of 13 vs. 39, p = 0.004; 5 vs. 19, p = .014, respectively). Lastly, the bivalirudin group had improved survival to ECMO decannulation in univariate analysis (median OS 53 vs. 26 days, p = .015).

CONCLUSIONS

In this real-world analysis of bivalirudin versus heparin, bivalirudin is a viable option for V-V ECMO and associated with lower risk of thrombotic complications and fewer transfusion requirements.

RhoA/rho kinase pathway activation in age-associated endothelial cell dysfunction and thrombosis

The small GTPase RhoA and the downstream Rho kinase (ROCK) regulate several cell functions and pathological processes in the vascular system that contribute to the age-dependent risk of cardiovascular disease, including endothelial dysfunction, excessive permeability, inflammation, impaired angiogenesis, abnormal vasoconstriction, decreased nitric oxide production and apoptosis. Frailty is a loss of physiological reserve and adaptive capacity with advanced age and is accompanied by a pro-inflammatory and pro-oxidative state that promotes vascular dysfunction and thrombosis. This review summarises the role of the RhoA/Rho kinase signalling pathway in endothelial dysfunction, the acquisition of the pro-thrombotic state and vascular ageing. We also discuss the possible role of RhoA/Rho kinase signalling as a promising therapeutic target for the prevention and treatment of age-related cardiovascular disease.

Difficult-to-treat primary immune thrombocytopenia in adults: Prevalence and burden. Results from the CARMEN-France registry

The aim of this study was to assess the prevalence and the burden of difficult-to-treat primary ITP (pITP), defined by the need for another ITP treatment after romiplostim and eltrombopag. Adult patients were selected in the prospective, real-world CARMEN-France registry up to December 2021. Out of 821 adult patients with pITP, 29 had difficult-to-treat ITP (3.5%; 95% confidence interval [CI]: 2.3%-4.8% in total; 7.6%; 95% CI: 4.9%-10.2% of patients needing ≥2nd line treatment). The 3-year cumulative incidence of bleeding, infection and thrombosis was 100%, 24.1% and 13.8% respectively. The median cumulative duration of hospital stays was 31 days (median follow-up: 30.3 months).

ADAMTS-13 conformation influences autoimmune recognition in immune thrombotic thrombocytopenic purpura

BACKGROUND

Patients with immune-mediated thrombotic thrombocytopenic purpura (iTTP) have anti-ADAMTS-13 immunoglobulin G (IgG) autoantibodies that enhance ADAMTS-13 clearance and/or inhibit its function. ADAMTS-13 normally circulates in a closed conformation, which is manifested by the interaction of the CUB domains with the central spacer domain. Disruption of the spacer-CUB interaction opens ADAMTS-13, which augments its proteolytic function but may also expose cryptic autoimmune epitopes that promote further autoantibody recognition.

OBJECTIVES

To explore differences in autoantibody binding to ADAMTS-13 in its closed or open conformations in patients with iTTP and to correlate these differences with disease-related parameters.

METHODS

We developed a novel assay to measure autoantibodies binding to closed and open ADAMTS-13. Autoantibody titer and IgG subclass binding to open or closed ADAMTS-13 were measured in 70 iTTP first presentation samples and correlated with clinical data, remission, and relapse.

RESULTS

In 70 patients with iTTP, the mean autoantibody titer against open ADAMTS-13 was, on average, approximately 2-fold greater than that against closed ADAMTS-13, suggesting that ADAMTS-13 opening increases epitope exposure and immune complex formation. Autoantibody titer against closed/open ADAMTS-13 and IgG subclass did not correlate with ADAMTS-13 antigen at presentation. Two patients with iTTP and persistent autoantibodies lost specificity for closed ADAMTS-13 in remission. Recognition of closed/open ADAMTS-13 and autoantibody IgG subclass between the first and second iTTP episodes were very similar.

CONCLUSION

ADAMTS-13 autoantibody binding is highly influenced by ADAMTS-13 conformation. Although this does not appear to modify the pathogenicity of autoantibodies, the autoantibody signature at relapse suggests that relapse represents re-emergence of the original autoimmune response rather than de novo presentation.

Acute Thrombosis of an Aneurysm of the Small Saphenous Vein: A Case Report

BACKGROUND

A venous aneurysm (VA) is a focal dilatation of a nonvariceal vein (diameter increased by at least 1.5 times compared to the adjacent upstream or downstream venous segment), which carries a risk of venous thromboembolism (VTE) when located in the deep veins of the lower limbs but also when it affects the veins above the muscle fascia.

CASE

We report the case of a 40-year-old woman who presented with a painful and disabling mass-like lesion of the upper third of the right calf. A Doppler ultrasound (DUS) examination revealed a small saphenous vein (SSV) dilated at the saphenopopliteal junction (SPJ) and thrombosed along its entire length. Anticoagulant treatment was initiated but although the thrombosis regressed on DUS, the functional impotence and the persistence of pain prompted a stripping of the SSV. Histology allowed the diagnosis of SSV's primary aneurysm.

DISCUSSION

Dilated segments of the saphenous vein are not always varicose veins (VVs). True VAs can develop on veins located above the muscular fascia and, like deep VAs, may trigger VTE. Small saphenous vein aneurysms have seldom been reported, and only a few clinical observations have described the thrombosis of a SSV aneurysm. Any mass in the popliteal fossa or upper part of the calf should be examined by DUS to look for an SSV aneurysm. Excision of the saphenous vein with junctional ligation is advised if thrombosis is present at the time of diagnosis.

Effect of prothrombin Belgrade mutation, causing antithrombin resistance, on fibrin clot properties

INTRODUCTION

Prothrombin Belgrade mutation is the result of the c.1787G>A substitution in the prothrombin gene. It is located in the antithrombin and sodium binding site and leads to impaired inactivation of thrombin by antithrombin, resulting in antithrombin resistance and thrombotic disorders. However, it negatively affects sodium binding and may have hypocoagulant effects. Considering that prothrombin Belgrade mutation mechanism is still not fully elucidated and that sodium binding is important for thrombin affinity towards fibrinogen, our aim was to determine whether this mutation affects fibrin clot formation and lysis.

METHODS

Using HEK293T cell line, recombinant wild type and mutated prothrombin were generated by transient transfection. Samples that correspond to plasma of a non-carrier, heterozygous and homozygous carriers were reconstituted using prothrombin deficient plasma and recombinant proteins. Reconstituted samples were used in OHP assay (Overall Hemostasis Potential) to determine kinetic profiles of coagulation and fibrinolysis. Clot turbidity assay was performed to observe kinetics of clot formation and lysis more closely. Fibrin clots formed in reconstituted plasma samples were analyzed by confocal microscopy to determine density of fibrin network. Fibrin clots were additionally observed using electron microscopy to determine thickness of individual fibrin fibers.

RESULTS

No significant difference found in OHP, OCP, OFP, and fibrin network density between wild type, heterozygous, and homozygous carrier reconstituted plasma samples. There were significant differences between samples for slope and slope time parameters in kinetic profiles and fibrin fiber thickness.

CONCLUSIONS

Results indicate that prothrombin Belgrade mutation has no significant impact on fibrinolysis, however it may affect kinetics of clot formation and its architecture.

Composition of thrombi in zebrafish: similarities and distinctions with mammals

BACKGROUND

Blood clots are primarily composed of red blood cells (RBCs), platelets/thrombocytes, and fibrin. Despite the similarities observed between mammals and zebrafish, the composition of fish thrombi is not as well known.

OBJECTIVES

To analyze the formation of zebrafish blood clots ex vivo and arterial and venous thrombi in vivo.

METHODS

Transgenic zebrafish lines and laser-mediated endothelial injury were used to determine the relative ratio of RBCs and thrombocytes in clots. Scanning electron and confocal microscopy provided high-resolution images of the structure of adult and larval clots. Adult and larval thrombocyte spreading on fibrinogen was evaluated ex vivo.

RESULTS

RBCs were present in arterial and venous thrombi, making up the majority of cells in both circulations. However, bloodless mutant fish demonstrated that fibrin clots can form in vivo in the absence of blood cells. Scanning electron and confocal microscopy showed that larval and adult zebrafish thrombi and mammalian thrombi look surprisingly similar externally and internally, even though the former have nucleated RBCs and thrombocytes. Although adult thrombocytes spread on fibrinogen, we found that larval cells do not fully activate without the addition of plasma from adult fish, suggesting a developmental deficiency of a plasma activating factor. Finally, mutants lacking αIIbβ3 demonstrated that this integrin mediates thrombocyte spreading on fibrinogen.

CONCLUSION

Our data showed strong conservation of arterial and venous and clot/thrombus formation across species, including developmental regulation of thrombocyte function. This correlation supports the possibility that mammals also do not absolutely require circulating cells to form fibrin clots in vivo.

Thrombosis risk with haemoglobin C trait and haemoglobin C disease: A systematic review

The thrombotic risk with haemoglobin C trait (HbAC) or haemoglobin C disease (HbCC) is unclear. However, individuals with HbCC have demonstrated chronic haemolysis, higher blood viscosity and altered rheology when compared to individuals with wild-type haemoglobin (HbAA). These physiological alterations may theoretically translate to increased risk of thrombosis; therefore, a systematic literature review was performed to investigate the possible association between HbAC and/or HbCC and thrombosis. Twenty-two studies met inclusion criteria representing 782 individuals with HbAC (n = 694) or HbCC (n = 88). Fifteen studies described the presence/absence of venous thromboembolism (VTE) in patients with HbAC (n = 685) or HbCC (n = 79), while seven studies described patients with HbAC (n = 9) or HbCC (n = 9) and arterial thrombosis. Most (n = 20) studies were case reports or case series; however, two studies suggested a potential increased VTE risk with HbAC compared to HbAA in (i) all patients (OR 2.2, 95% CI: 0.9-5.5) and in (ii) pregnant individuals (RR 3.7, 95% CI 0.9-16). This review is the largest assessment of patients with HbC trait or disease and thrombosis to date; despite its limitations, the findings suggest HbC may be a predisposing risk factor to thrombosis. Prospective cohort studies are warranted to definitively elucidate the risk of thrombosis in this population.