Thrombosis research最新文献

Plasma proteins involved in coagulation and fibrinolysis are essential to hemostasis. Consequently, their circulating levels and functionality are critical in bleeding and thrombosis development. Well-established laboratory tests to assess these are available; however, said tests do not allow high multiplicity, require large volumes of plasma and are often costly. A novel technology to quantify plasma proteins is quantitative protein mass spectrometry (QPMS). Aided by stable isotope-labeled internal standards a large number of proteins can be quantified in one single analytical run requiring <30 μL of plasma. This provides an opportunity to improve insight in the etiology and prognosis of bleeding and thrombotic disorders, in which the balance between different proteins plays a crucial role. This manuscript aims to give an overview of the QPMS potential applications in thrombosis and hemostasis research (quantifying the 38 proteins assigned to coagulation and fibrinolysis by the KEGG database), but also to explore the potential and hurdles if designed for clinical practice. Advantages and limitations of QPMS are described and strategies for improved analysis are proposed, using as an example the test requirements for antithrombin. Application of this technology in the future could represent a step towards individualized patient care.

Introduction

A variety of thromboprophylaxis regimens have been administered in patients following the Fontan procedure. However, consensus guidelines regarding the optimal thromboprophylaxis strategy have not yet been developed.

Method

A network meta-analysis was conducted to evaluate the comparative effectiveness among available thromboprophylaxis regimens and major bleeding events associated with these regimens.

Results

A total of 28 comparative studies with 4430 Fontan patients were included. The incidence of thromboembolic events (TE) was significantly lower in individuals who underwent thromboprophylaxis compared to those who did not. Compared to a no-treatment strategy, nonvitamin K oral anticoagulants (NOACs) showed the largest treatment effect for preventing TE (OR = 0.08, 95 % CI 0.03 to 0.21), followed by warfarin (OR = 0.16, 95 % CI 0.10 to 0.27), and aspirin (OR = 0.23, 95 % CI 0.14 to 0.38). Indeed, NOACs were significantly more effective than aspirin in preventing TE (OR = 0.35, 95 % CI 0.14 to 0.84). Aspirin was associated with the lowest occurrence of major bleeding events, followed by NOACs, no medication, and warfarin. NOACs were shown to possess a highly favorable overall profile.

Conclusion

Prescribing thromboprophylaxis drugs, either antiplatelets or anticoagulants, may be more effective in preventing TE after the Fontan operation than not doing so. Among the included regimens, NOACs demonstrated significantly greater efficacy than aspirin; however, they did not show statistically significant superiority over warfarin. Aspirin exhibited lower rates of major bleeding compared to both NOACs and warfarin. Overall, NOACs tended to offer the most advantageous balance of efficacy and safety. However, the findings should be interpreted considering the certainty and limitations of the evidence, including potential residual confounding in observational studies.

Background

Leukocyte-platelet aggregates comprise a pathogenic link between hemostasis and immunity, but the prerequisites and mechanisms of their formation remain not understood.

Aims

To quantify the formation, composition, and morphology of leukocyte-platelet aggregates in vitro under the influence of various cellular activators.

Methods

Phorbol-12-myristate-13-acetate (PMA), lipopolysaccharide (LPS), thrombin receptor-activating peptide (TRAP-6), and adenosine diphosphate (ADP) were used as cellular activators. Flow cytometry was utilized to identify and quantify aggregates in whole human blood and platelet-rich plasma. Cell types and cellular aggregates were identified using fluorescently labeled antibodies against the appropriate cellular markers, and cell activation was assessed by the expression of appropriate surface markers. For confocal fluorescent microscopy, cell membranes and nuclei were labeled. Neutrophil-platelet aggregates were studied using scanning electron microscopy.

Results

In the presence of PMA, ADP or TRAP-6, about 17–38 % of neutrophils and 61–77 % of monocytes formed aggregates with platelets in whole blood, whereas LPS did not induce platelet aggregation with either neutrophils or monocytes due the inability to activate platelets. Similar results were obtained when isolated neutrophils were added to platelet-rich plasma. All the cell types involved in the heterotypic aggregation expressed molecular markers of activation. Fluorescent and electron microscopy of the aggregates showed that the predominant platelet/leukocyte ratios were 1:1 and 2:1.

Conclusions

Formation of leukocyte-platelet aggregates depends on the nature of the cellular activator and the spectrum of its cell-activating ability. An indispensable condition for formation of leukocyte-platelet aggregates is activation of all cell types including platelets, which is the restrictive step.

Background

Severe aortic stenosis (sAS) is associated with acquired von Willebrand syndrome (AVWS) by loss of high-molecular-weight multimers (HMWM) of von Willebrand factor (VWF), potentially resulting in perioperative bleeding. Analysis of VWF multimers remains challenging. Recently, the new, rapid Hydragel 5 assay has been developed, using electrophoretic protein separation for dividing VWF-multimers into low (LMWM), intermediate (IMWM), and HMWM, the hemostatically active part of VWF. Here, we evaluated its impact on predicting blood loss in presence of AVWS after surgical aortic valve replacement (SAVR).

Methods

We prospectively examined 52 patients (age: 68 ± 7 years; 54 % male) admitted to SAVR. They were divided in two groups (A: normal VWF, n = 28; B: abnormal VWF, n = 24, defined as VWF-activity/antigen (VWF:Ac/Ag)-ratio < 0.7 and/or HMWM loss). Blood samples and echocardiographic data were collected before, seven days and three months after SAVR. Blood loss and transfusions were recorded.

Results

Baseline characteristics and clinical data were similar in both groups. HMWM loss was present in 38.5 % of all patients. HMWM, the VWF:Ac/Ag- and HMWM/(IMWM+LMWM)-ratios were significantly decreased preoperatively in group B but normalized after SAVR. Bleeding, re-thoracotomy and transfusion rates were comparable. HMWM loss was inversely correlated with the peak aortic gradient (Pmax) and positively with the aortic valve area (AVA), while HMWM/(IMWM+LMWM)-ratio negatively correlated with the mean aortic gradient (Pmean).

Conclusion

HMWM and HMWM/(IMWM+LMWM)-ratio inversely correlate with severity of AS and normalize after SAVR. The Hydragel-5 assay's might be valuable for routine diagnostics to assess bleeding risk and postoperative normalization of AS and VWF abnormalities in SAVR patients.

Introduction

The 2021 Surviving Sepsis Campaign guidelines recommend low-molecular-weight heparin for the prevention of venous thromboembolism in sepsis. However, observational studies suggest that anticoagulants as a whole may benefit severely ill sepsis patients with coagulopathy, but the optimal targets of unfractionated heparin remain unclear. This study investigated which sepsis patients could most benefit from unfractionated heparin.

Materials and methods

In this retrospective observational study, we identified adult sepsis patients requiring urgent hospitalization from 2006 to 2019 using a large-scale Japanese medical database. Patients were divided into two groups: those receiving unfractionated heparin within 72 h of admission and those who did not. We compared in-hospital mortality, major bleeding complications, and thromboembolic events between these groups using a multivariate logistic regression model adjusted for patient and treatment variables. Additionally, we assessed the association between heparin administration and in-hospital mortality across various subgroups.

Results

Among 30,342 sepsis patients, 2520 received early heparin administration, and 27,822 did not. Multivariate logistic regression revealed a significant association between heparin and reduced in-hospital mortality (adjusted OR: 0.735, 95 % CI: 0.596–0.903) but no significant association with major bleeding and thromboembolic risk (adjusted OR: 1.137, 1.243; 95 % CI: 0.926–1.391, 0.853–1.788, respectively). Subgroup analyses suggested significant survival benefits associated with heparin only in the sepsis patients with moderate coagulopathy and sepsis-induced coagulopathy scores of 3 or 4 (adjusted OR: 0.452, 0.625; 95 % CI: 0.265–0.751, 0.410–0.940, respectively).

Conclusions

Early heparin administration upon admission is associated with lower in-hospital mortality, especially in moderate sepsis-induced coagulopathy, and no significant increase in complications.

Introduction

Hormone therapy (HT) for breast cancer is associated with an increased risk of venous thromboembolism (VTE). This study examines the effects of continuing versus discontinuing HT on VTE recurrence, major bleeding, and mortality, after an acute VTE event.

Methods

Using data in the RIETE-registry from March 2001 through September 2021, we calculated incidence rates and rate-ratios (RR) for VTE events in patients on- and off HT. Cox regression models assessed the impact of HT continuation.

Results

Among 479 women with breast cancer on HT who developed VTE (pulmonary embolism 279, isolated deep vein thrombosis 200), 350 (73 %) continued HT. These women were slightly older (70 ± 13 vs. 67 ± 16 years) than those discontinuing HT, with no significant differences in other baseline characteristics. Over a median follow-up of 294 days, 25 (5.2 %) developed VTE recurrences, 18 (3.7 %) had major bleeding, and 73 (15.2 %) died. Rates of VTE recurrence did not differ significantly between groups (RR: 1.28, 95 % CI 0.44–3.75), except in the first three months post-VTE, where a higher rate was observed in those continuing HT (6.02/100 patients-year vs. no events). On multivariable analysis, HT continuation showed no association with VTE recurrences after adjusting for other thromboembolic risk factors (adjusted hazard ratio [aHR] 1.49, 95 % CI 0.5–4.45).

Conclusion

Continuing HT after a VTE event in women with breast cancer does not generally affect the long-term risk of VTE recurrences but is associated with a higher risk in the first three months. These findings highlight the need for careful monitoring during this period.

Introduction

Heatstroke is a critical heat-related condition characterized by coagulopathy and multiple organ dysfunction. One of the most severe complications of heatstroke is disseminated intravascular coagulation. This condition manifests as excessive clot formation and bleeding that are primarily due to platelet depletion and dysfunction. Fibrinogen plays a crucial role in hemostasis because it links integrin αIIbβ3 on adjacent platelets, thereby promoting the platelet activation and aggregation necessary for clot formation. However, reduced fibrinogen levels may impair the formation of the initial platelet plug and increase the risk of bleeding. The current study explored the effect of fibrinogen on platelet dysfunction in a heatstroke model.

Materials and methods

Male Wistar rats were subjected to heat stress, and subsequent changes in hemodynamic, biochemical, and coagulation parameters were analyzed. Platelet viability, aggregation, adhesion, spreading and fibrin clot retraction were assessed.

Results

The rats with heatstroke exhibited a variety of clinical symptoms, including hypotension, tachycardia, multiple organ dysfunction, and coagulopathy. Platelet viability in the heatstroke group was comparable to that in the healthy control group. However, the heatstroke group exhibited significant reductions in plasma fibrinogen levels and platelet aggregation, adhesion, spreading, and fibrin clot retraction. Notably, fibrinogen supplementation markedly augmented the aggregation responses of platelets in the heatstroke group. The impairment of platelet adhesion, spreading, and fibrin clot retraction in the rats with heatstroke was partially ameliorated by fibrinogen supplementation.

Conclusions

An early use of fibrinogen replacement may serve as a therapeutic intervention to alleviate platelet hyporeactivity and prevent the complications in patients with heatstroke.

Introduction

Postthrombotic syndrome (PTS), a common complication of deep vein thrombosis (DVT), is largely inflammatory by nature with contribution of prothrombotic mechanisms. The role of factor (F)XI in PTS has not been explored yet. We investigated whether elevated FXI is associated with PTS occurrence.

Materials and methods

We enrolled 180 consecutive patients (aged 43 ± 13 years) with first-ever DVT. After 3 months FXI levels were measured, along with inflammatory markers, thrombin generation, plasma clot permeability (Ks), clot lysis time (CLT), and fibrinolysis proteins. We assessed PTS using the Villalta score and recorded symptomatic venous thromboembolism (VTE) at a 1-year and venous ulcers at a median 53 months follow-up.

Results

Baseline median FXI was 102 % [IQR 92–113 %] and showed positive association with Villalta score (R = 0.474, P < 0.001). Patients with PTS (n = 48, 26.7 %) had 16.1 % higher FXI (P < 0.001) and FXI ≥120 % occurred more often in PTS patients (odds ratio [OR] 5.55, 95 % confidence interval [CI] 2.28–13.47). There were associations of baseline FXI with Ks and CLT along with thrombin activatable fibrinolysis inhibitor (TAFI) activity, C-reactive protein, and interleukin-6, but not with fibrinogen, or thrombin generation. After age adjustment higher FXI was independently associated with PTS occurrence (OR per 1 % 1.06, 95 % CI 1.02–1.09) and VTE recurrence (OR 1.03, 95 % CI 1.01–1.06). At long-term follow-up, patients with venous ulcers had 13.6 % higher baseline FXI (P = 0.002).

Conclusions

Elevated FXI in association with inflammation and prothrombotic fibrin clot properties may contribute to the development of PTS following DVT.