Endovascular Intervention Reduces Thrombosis Risk in Retrievable Inferior Vena Cava Filters: A Multicenter Propensity-Matched Analysis.

Five-year population-based study of essential thrombocythemia in Taiwan: Epidemiology, treatment patterns, and sex-based disparities.

A State-of-the-Art lecture entitled "Allele-selective von Willebrand Factor (VWF) silencing" was presented at the International Society on Thrombosis and Haemostasis (ISTH) congress in 2025. The concept, potential applications, and feasibility of allele-selective VWF inhibition will be discussed in detail in this review. VWF plays a crucial role in supporting hemostasis, which is important in bleeding as well as thrombotic disorders. Decreased or functionally defective VWF results in von Willebrand disease (VWD), whereas high VWF levels have been associated with thrombotic risk. By silencing the synthesis of VWF from the mutant VWF gene in VWD, one might eliminate the production of mutant VWF and thereby normalize multimer composition and increase the levels of functional VWF. This would lead to phenotypic improvement in VWD. In the context of high plasma VWF levels and thrombotic disorders, silencing of one VWF allele will lower VWF in the circulation and endothelial cells, but at the same time, allele-selective silencing prevents an excessive reduction in VWF levels. Limited VWF reduction will reduce thrombosis risk without inducing bleeding. Selectively silencing the expression of one VWF allele, based on a single nucleotide difference between the 2 alleles, using small interfering RNAs has proven to be successful. This approach resulted in phenotypic improvement for VWD in vitro as well as in vivo. Preliminary data in the context of thrombotic risk indicated that silencing one VWF allele reduced thrombosis development without increasing bleeding. Finally, we summarize relevant new data on other new treatments for VWD presented during the 2025 ISTH Congress.

Computational fluid dynamics-based risk stratification of modified Blalock-Taussig-Thomas shunt thrombogenicity.

Background: The modified Blalock-Taussig-Thomas shunt (mBTTS) is a critical palliative procedure for infants with single-ventricle physiology, but thrombosis-related occlusion affects 8-12% of cases and carries nearly 50% mortality. Meanwhile, existing antithrombotic strategies fail to address the hemodynamic factors driving thrombosis, highlighting the need for a deeper understanding of flow dynamics in shunt failure. Research Question: Can engineering principles inform and optimize procedural interventions to reduce flow-mediated platelet activation and subsequent aggregation? Aims: This study aims to identify how mBTTS geometry influences hemodynamics and thrombosis risk, providing quantitative guidance for surgical planning and shunt design optimization. Methods: We used patient-specific imaging data to construct 54 idealized mBTTS configurations, systematically varying key geometric factors; pulmonary artery diameter, shunt diameter, and insertion angle. Using computational fluid dynamics, we analyzed how these variables influence wall shear rate (WSR), elongational strain rate (ESR), and turbulence intensity (TI); hemodynamic parameters known to affect thrombosis risk, to identify patterns linked to thrombosis. Results: We computationally identified optimal geometric configurations. Peak Wall Shear Rate (WSR) and Elongational Strain Rate (ESR) were primarily located at bifurcation points, while peak Turbulence Intensity (TI) was concentrated within the shunt channel. Shunt insertion distal to the right carotid artery with a 60° insertion angle and with a 4.0mm shunt graft demonstrated the most favorable hemodynamic profiles to prevent clots. Statistical analysis confirmed strong correlations between geometric parameters and flow characteristics. Conclusion: Results provide a framework for optimizing mBTTS design to reduce thrombosis risk based on hemodynamic risk factors, including actionable recommendations for shunt placement and design. These insights provide a foundation for hemodynamically guided surgical interventions with potential to improve survival rates in this high-risk patient population and for broader applications in cardiovascular surgery.

Discovery and preclinical characterization of SB-01, a novel allosteric inhibitor of human factor XIa

Catheter-related thrombosis (CRT) is a consequential complication in patients receiving long-term home parenteral nutrition (HPN), compromising central venous access, nutrition support and, in some cases, survival. Yet whether routine prophylactic anticoagulation should be used to prevent CRT remains a clinical dilemma: although thrombosis prevention may preserve venous access, anticoagulation introduces bleeding risk, monitoring demands, added treatment burden, lifestyle restrictions, and cost. Proponents cite the relatively high incidence and clinical consequences of CRT, supported by observational data suggesting reduced thrombosis risk with prophylaxis. Opponents emphasize bleeding risks, lack of randomized controlled trial (RCT) evidence, and the improved safety of modern catheter care without anticoagulation. Consequently, practice varies widely, from routine anticoagulation to selective, risk-based approaches. This review critically evaluates the arguments on both sides, drawing on evidence from adult and pediatric cohorts. Beyond clinical outcomes, it considers the quality-of-life implications that daily anticoagulation imposes on an already complex HPN regimen. Routine anticoagulation in HPN sits at the intersection of prevention and harm: it may be appropriate for selected high-risk patients, but it is not a one-size-fits-all solution. An individualized, multidisciplinary approach, balancing thrombotic and bleeding risk alongside patient preference, is essential. Future research, including RCTs and predictive risk tools, is needed to refine patient selection and optimize strategies to preserve the venous lifelines sustaining HPN.

Ultraendurance races such as trail ultramarathons push human physiology to extremes, including the blood’s clotting (hemostatic) system. Although regular moderate exercise reduces thrombosis risk and promotes cardiovascular health, extreme efforts tell a more complex story. Events like 50 to 100 km trail runs create a cocktail of dehydration, inflammation, muscle damage, and exertional heat stress—all of which perturb hemostasis. Indeed, thromboembolic events have been documented in otherwise healthy marathoners [1–4].

Patients with coronary-artery disease (CAD) and type 2 diabetes mellitus (T2DM) are often in a hypercoagulable state and have an increased thrombosis risk. We aimed to evaluate the effects of sodium/glucose cotransporter 2 inhibitors (SGLT2is) on coagulation function and explore their potential role in regulating coagulation in these patients. We conducted a retrospective cohort study between June 2020 and June 2024 in patients with CAD and T2DM. Eligible patients were assigned to either the SGLT2i or non-SGLT2i group. Clinical information, laboratory tests, and echocardiographic (EKG) examination results were retrieved. We performed inter- and intragroup comparisons of coagulation function measurements before and after treatment, and also conducted regression analysis to assess the impact of treatment on coagulation function. A total of 121 patients were included, with 49 and 72 in the SGLT2i and non-SGLT2i groups, respectively. After 30 days of treatment, antithrombin III (AT-III) activity increased by 5.39% (P = 0.026) in the SGLT2i group, but slightly decreased in the non-SGLT2i group. SGLT2 is also decreased D-dimer levels by 95 mg/L (group P = 0.051, group:time P = 0.075). Further regression analysis showed a significant interaction between group and time for AT-III and D-dimer (P = 0.026 and P = 0.039). Additionally, prothrombin time (PT) showed a slight increase after SGLT2i treatment. SGLT2is could affect coagulation function by prolonging coagulation time and increasing anticoagulatory activity in patients with T2DM and CAD. These drugs could be used to ameliorate hypercoagulable states and reduce thrombosis risk in these patients.

The modified Blalock-Taussig-Thomas shunt (mBTTS) is a critical palliative procedure for infants with single-ventricle physiology, but thrombosis-related occlusion affects 8-12% of cases and carries nearly 50% mortality. Meanwhile, existing antithrombotic strategies fail to address the hemodynamic factors driving thrombosis, highlighting the need for a deeper understanding of flow dynamics in shunt failure. This study aims to identify how mBTTS geometry influences hemodynamics and thrombosis risk, providing quantitative guidance for surgical planning and shunt design optimization. We used patient-specific imaging data to construct 54 idealized mBTTS configurations, systematically varying key geometric factors; pulmonary artery diameter, shunt diameter, and insertion angle. Using computational fluid dynamics, we analyzed how these variables influence wall shear rate (WSR), elongational strain rate (ESR), and turbulence intensity (TI); hemodynamic parameters known to affect thrombosis risk, to identify patterns linked to thrombosis. We computationally identified optimal geometric configurations. Peak WSR and ESR were primarily located at bifurcation points, while peak TI was concentrated within the shunt channel. Shunt insertion distal to the right carotid artery with a 60° insertion angle and with a 4.0mm shunt graft demonstrated the most favorable hemodynamic profiles to prevent clots. Statistical analysis confirmed strong correlations between geometric parameters and flow characteristics. Results provide a framework for optimizing mBTTS design to reduce thrombosis risk based on hemodynamic risk factors, including actionable recommendations for shunt placement and design. These insights provide a foundation for hemodynamically guided surgical interventions with potential to improve survival rates in this high-risk patient population and for broader applications in cardiovascular surgery.

Heparin-induced thrombocytopenia (HIT) is a serious adverse reaction to heparin, associated with increased risk of thromboembolic complications. Intravenous immunoglobulins (IVIGs) have been used as a therapeutic for HIT and are believed to alleviate thrombocytopenia and reduce thrombosis risk. Yet the antithrombotic effects of IVIG in HIT remain underexplored. To investigate the effect of IVIG on thrombus formation in an exvivo model of HIT-IgG-induced thrombosis. Microfluidic channels were coated with a confluent monolayer of human umbilical vein endothelial cells that were primed with TNF-α to induce an activated, inflammatory state. Whole blood was exposed to unfractionated heparin, with or without IVIG before subjecting to treatment with a monoclonal HIT-like antibody (K070), or HIT-patient-IgG. Recalcified blood was perfused over human umbilical vein endothelial cells at venous shear stress. Thrombus structure and dynamics were investigated by immunofluorescence microscopy. HIT-patient-IgGs and K070 induced thrombus formation in the presence of prophylactic heparin exposure, over TNF-α treated, inflamed endothelial cells. HIT thrombi were enriched in fibrin, phosphatidylserine-bearing platelets, and leukocyte aggregates. We observed thrombi being formed on adherent platelets, which gradually recruited leukocytes into a three-dimensional thrombus structure. Pretreatment of blood with IVIG significantly reduced cellular adhesions and prevented thrombus formation. Our endothelialized exvivo flow chamber system effectively recapitulates the immunothrombotic phenotype of HIT and offers a reliable tool to urgently validate the efficacy of IVIG intervention against HIT-IgG-induced thrombosis in patients.

Arteriovenous fistula (AVF) thrombosis is a major vascular access complication in hemodialysis (HD) patients, contributing to increased morbidity. Statins, known for their pleiotropic effects, may reduce AVF thrombosis risk, but evidence on dose-dependent effects is limited. This study evaluated the association between statin use, dose intensity, and AVF thrombosis in HD patients. Methods. A multicenter, retrospective cohort study was conducted using data from 562 HD patients with native AVFs across 10 dialysis clinics (May 2021–April 2025). Patients were categorized by statin use (users vs. non-users) and dose intensity (moderate vs. high vs. none). The primary outcome was AVF thrombosis; death was treated as a competing event. Kaplan-Meier survival curves and Fine and Gray subdistribution hazard models, adjusted for age, diabetes, dialysis vintage, Kt/V, glucose, calcium, blood flow, and pre-HD cardiovascular disease, were used to assess thrombosis risk. Results. Of 562 patients (median follow-up 59 months), 212 (37.7%) were statin users. AVF thrombosis occurred in 54 (9.6%) patients, with 11 (7.1%) in statin users vs. 43 (10.6%) in non-users (p = 0.006). Kaplan-Meier analysis showed lower thrombosis probability in statin users (log-rank p = 0.001), with high-intensity users having the lowest risk (p = 0.004). In the unadjusted Fine and Gray model, high-intensity statins were associated with reduced thrombosis risk (sHR 0.61, 95% CI 0.59–0.97, p = 0.03), with a significant dose-dependent trend (p = 0.018). The adjusted model showed no significant association (moderate: sHR 0.67, p = 0.16; high: sHR 0.57, p = 0.26). Conclusions. Statin use, particularly high-intensity, may reduce AVF thrombosis risk in HD patients, with a dose-dependent trend in unadjusted analyses. However, adjusted results were non-significant, possibly due to limited events. Larger prospective studies are needed to confirm these findings and optimize statin therapy for vascular access preservation.

Hemodialysis is an important means to sustain life in patients with end-stage renal disease In China, more than 100,000 hemodialysis patients need to have a catheter fitted at least once (temporary or long term) for dialysis. Despite the widespread use and low cost of HD catheters, they remain prone to critical issues such as high thrombosis rates, infections, and dysfunction. This study addresses the persistent challenge of thrombosis formation in dialysis catheters by investigating the incorporation of helical flow inducers, a strategy inspired by the naturally occurring helical blood flow in arterial systems. In this research, helical flow inducers with varying pitch and diameter were integrated into the widely used Niagara@ catheter. Computational fluid dynamics simulations were conducted to evaluate the impact on key parameters such as local normalized helicity (LNH), residence time (RT), shear stress, and flow velocity. The results demonstrated that 1) small-diameter inducers produce helical flow. Among inducers with identical diameter, those with a smaller thread pitch are more likely to induce increased LNH; 2) a small thread pitch helical flow inducer reduced the percentage of blood volume, with RT exceeding 0.015 s from 40.8% in the control to 12.7%, suggesting a substantial reduction in thrombosis risk; 3) the study also found that the introduction of small thread pitch helical flow inducers led to increased shear stress, with Model A showing an average shear stress of 49.2 Pa, compared to 32.0 Pa in the control. This highlights the need for careful optimization to balance the benefits of reduced thrombosis risk with the potential for shear-induced hemolysis. In conclusion, the integration of helical flow inducers into dialysis catheters offers a promising strategy for improving intraluminal flow dynamics and reducing the risk of thrombosis.

BackgroundThrombosis in modified Blalock‐Taussig‐Thomas shunts (mBTTS) poses a life‐threatening risk for infants with shunt‐dependent congenital heart disease. Although hemodynamics influence thrombosis, the specific geometric contributors remain unclear. This study aimed to identify key variables to inform future hemodynamic analysis, hypothesizing that brachiocephalic, subclavian artery, mBTTS, and/or pulmonary artery (PA) geometry play a critical role in clot formation.Methods and ResultsWe retrospectively analyzed 11 infants with hypoplastic left heart syndrome who underwent mBTTS placement. Using computed tomography and magnetic resonance imaging, we generated 3‐dimensional models of the shunt and surrounding vasculature. Geometric variables related to shunt positioning and vascular insertion were measured and compared between patients with (n=5) and without (n=6) thrombotic occlusions. Significant differences in vascular geometry were observed between occluded and nonoccluded shunts. Occluded shunts had longer PA lengths (12.4 mm versus 8.4 mm, P=0.0130), increased variance in PA radius (0.03 versus 0.008, P=0.0216), greater PA tortuosity (1.03 versus 1.01, P=0.0043), and increased variance in torsion across the brachiocephalic and subclavian arteries (3200 mm−1 versus 17 500 mm−1, P=0.0390). These findings support our hypothesis that the vascular geometry surrounding the mBTTS plays a critical factor in clot formation. Additional variations in PA, brachiocephalic and subclavian artery geometry approached significance.ConclusionsSignificant geometric differences in the PA, brachiocephalic, and subclavian arteries were associated with mBTTS thrombosis, supporting the hypothesis that vascular geometry plays a critical role in clot formation. These findings provide a foundation for future hemodynamic analyses and may inform surgical planning to reduce thrombosis risk in patients with mBTTSs.

Use of Affimer technology for inhibition of α2-antiplasmin and enhancement of fibrinolysis

Iron Deficiency Correction in Myeloproliferative Neoplasms Reduces Thrombosis Risk Via Decreased P-Selectin

BackgroundParoxysmal nocturnal hemoglobinuria (PNH) is a rare, chronic blood disorder. Symptoms such as fatigue can have a substantial impact on patients’ physical activity levels, sleep, quality of life, and work productivity. Ravulizumab treatment can reduce thrombosis risk, improve survival and quality of life, and reduce fatigue in PNH, but information is limited on how it impacts sleep and physical activity. Here, data on resting heart rate, daily physical activity, and sleep in ravulizumab-treated patients with PNH were passively collected via a digital wearable activity-tracking device and patient-reported outcome (PRO) data were collected via weekly surveys in the same cohort.MethodsREVEAL was a 32-week prospective observational cohort study in individuals with PNH receiving ravulizumab in the USA. A wrist-worn Fitbit™ collected data on resting heart rate, daily step count, and sleep duration from eligible patients. Patients also completed the following electronic weekly surveys: Functional Assessment of Chronic Illness Therapy (FACIT) – Fatigue, Patient-Reported Outcomes Measurement Information System (PROMIS) Global Physical Health, PROMIS Global Mental Health, PROMIS Sleep-Related Impairment and Sleep Disturbance, and Work Productivity and Activity Impairment Questionnaire – Specific Health Problem (WPAI-SHP). Data collected from the activity trackers and surveys were compared against US general population values reported in the literature.ResultsTwenty-eight ravulizumab-treated patients were included (median age: 34 years; 54% female). PRO scores were within US general population normative values, including FACIT-Fatigue (40.0), PROMIS Global Physical Health (51.0), Global Mental Health (51.0), Sleep-Related Impairment (50.0), and Sleep Disturbance (49.0). Similarly, mean resting heart rate (67 bpm), daily step count (7476), and sleep duration (7.7 h) were within the range of US general population values. Daily step count was positively correlated with PROMIS Global Physical and Mental Health scores.ConclusionsThis was the first study to use digital monitoring technology to collect data on physical activity and sleep in patients with PNH. The findings indicate that ravulizumab treatment enables patients with PNH to achieve activity levels (heart rate, sleep duration, step count) and quality of life that are comparable to those of the US general population. A weak positive correlation was identified between patient-reported physical and mental health and daily physical activity levels.

Efficacy and Safety of Single Agent Proximal Complement Inhibitors in Paroxysmal Nocturnal Hemoglobinuria (PNH) Patients with Residual Anemia Despite of Adequate Terminal Complement Inhibitor Use

Extant clinical research has underscored that patients suffering from atrial fibrillation (AF) bear an elevated risk for stroke, predominantly driven by the formation of thrombus in the left atrial appendage (LAA). As such, accurately identifying those at an increased risk of thrombosis becomes paramount to facilitate timely and effective treatment. This study was designed to shed light on the mechanisms underlying thrombus formation in the LAA by employing three-dimensional (3D) left atrium (LA) models of AF patients, which were constructed based on Computed Tomography (CT) imaging. The distinct benefits of Computational Fluid Dynamics (CFD) were leveraged to simulate the blood flow field within the LA, using three distinct blood flow models, both under AF and sinus rhythm (SR) conditions. The potential risk of thrombus formation was evaluated by analyzing the Relative Residence Time (RRT) and Endothelial Cell Activation Potential (ECAP) values. The results gleaned from this study affirm that all three blood flow models align with extant clinical guidelines, thereby enabling an effective prediction of thrombosis risk. However, noteworthy differences emerged when comparing the intricacies of the flow field and thrombosis risk across the three models. The single-phase non-Newtonian blood flow model resulted in comparatively lower residence times for blood within the LA and lower values for the Oscillatory Shear Index (OSI), RRT, and ECAP within the LAA. These findings suggest a reduced thrombosis risk. Conversely, the two-phase non-Newtonian blood flow model exhibited a higher residence time for blood and elevated RRT value within the LAA, suggesting an increased risk for thrombosis.

Background: Venoarterial extracorporeal membrane oxygenation (VA ECMO) supports critically ill patients with refractory cardiopulmonary failure. Drainage cannulae remove venous blood from the patient, but variability in cannula selection and tip position may impact flow dynamics and thrombosis risk. Therefore, this study investigated the effect of tip position of single-stage (SS) and multi-stage (MS) VA ECMO drainage cannulae on the risk of thrombosis. Methods: Computational fluid dynamics was used to model flow dynamics within a patient-specific geometry of the venae cavae. The tip of the SS and MS cannulae was modelled in the superior vena cava (SVC), SVC-Right atrium (RA) junction, mid-RA, inferior vena cava (IVC)-RA junction, and IVC. Constant mass flow rates were applied at all major vein inlets reflecting normal physiological flows. Drainage flow rates of the cannula were set at a constant 4 L/min throughout all simulations. The risk of thrombosis was assessed by measuring blood residence time, stagnant volume, rate of blood washout, and high wall shear stress. Results: Changes in the tip position of the SS cannula resulted in variability of thrombosis risk, whereas the MS cannula showed similar thrombosis risk during all simulations. The SS cannula showed reduced thrombosis risk arising from stagnant regions when placed in the SVC or SVC-RA junction, whereas an MS cannula was predicted to create stagnant regions during all tip positions (Figure 1). Conversely, the risk of thrombosis was increased in all positions with the SS cannula arising from higher maximum wall shear stresses (Table 1). When positioned in the IVC-RA junction and IVC, the SS cannula exhibited higher risk of thrombosis arising due to both high and low shear, compared to the MS cannula. Conclusion: Tip position of the drainage cannula impacts cannula flow dynamics and, subsequently, the risk of thrombosis. The use of MS cannulae can reduce high shear-related thrombosis, but SS cannulae can eliminate stagnant regions when advanced into the SVC. Therefore, the choice of cannula design and tip position should be carefully considered during cannulation.Figure 1. Comparison of stagnation regions between the single-stage (a) and multi-stage (b) cannulae at varying tip positions.