Plasma levels of haemostatic factors in patients with pulmonary embolism on admission and seven months later

Contemporary Biomarkers in Pulmonary Embolism Diagnosis: Moving beyond D-Dimers

Pulmonary embolism (PE) is a rather common cardiovascular disorder constituting one of the major manifestations of venous thromboembolism (VTE). It is associated with high mortality and substantial recurrence rates, and its diagnosis may be challenging, especially in patients with respiratory comorbidities. Therefore, providing a prompt and accurate diagnosis for PE through developing highly sensitive and specific diagnostic algorithms would be of paramount importance. There is sound evidence supporting the use of biomarkers to enhance the diagnosis and predict the recurrence risk in patients with PE. Therefore, several novel biomarkers, such as factor VIII, Ischemia Modified Albumin, and fibrinogen, as well as several MicroRNAs and microparticles, have been investigated for the diagnosis of this clinical entity. The present review targets to comprehensively present the literature regarding the novel diagnostic biomarkers for PE, as well as to discuss the evidence for their use in daily routine.

Prediction value of plasma D-dimer level changes on venous thromboembolism during pregnancy

OBJECTIVE

To explore the changes in plasma D-dimer (D-D) levels of pregnant women during pregnancy and their predictive value for venous thromboembolism (VTE).

METHODS

A selection of 240 pregnant women who came to our hospital for routine perinatal care and delivery from January 2018 to January 2019 were selected as the observation group, and 240 cases that came to our hospital for routine physical examination were served as the control group. The D-D levels of the two groups of women were compared, and the D-D levels of pregnant women in the observation group with different delivery methods were explored; the observation group was into VTE and non-VTE groups according to the occurrence of VTE, and the D-D levels of the two groups of pregnant women in different periods were compared, and its predictive value on VTE was analyzed.

RESULTS

The observation group exhibited a notably higher D-D level than the control group (p < .001), and the D-D level of the observation group during the first trimester was lower than the second and third trimesters, with statistical difference observed (p < .001), and the second trimester was much lower than the third trimester (p < .001); the D-D level in pregnant women with vaginal delivery showed lower level when comparing with women with cesarean section (p < .001); the D-D level of the VTE group was remarkably higher than that of the non-VTE group (p < .05); the D-D level during the second trimester had the highest predictive value for VTE, with the optimal cutoff value of 1.40 mg/L, the sensitivity of 69.3%, and the specificity of 76.7%, and AUC = 0.73.

CONCLUSION

The D-D of pregnant women during pregnancy showed an increase trend with the gestational weeks, and they were all beyond the normal range. The D-D level in the second trimester has the highest predictive value for VTE.

Platelet Phenotype Analysis of COVID-19 Patients Reveals Progressive Changes in the Activation of Integrin αIIbβ3, F13A1, the SARS-CoV-2 Target EIF4A1 and Annexin A5

Background: The fatal consequences of an infection with severe acute respiratory syndrome coronavirus 2 are not only caused by severe pneumonia, but also by thrombosis. Platelets are important regulators of thrombosis, but their involvement in the pathogenesis of COVID-19 is largely unknown. The aim of this study was to determine their functional and biochemical profile in patients with COVID-19 in dependence of mortality within 5-days after hospitalization. Methods: The COVID-19-related platelet phenotype was examined by analyzing their basal activation state via integrin αIIbβ3 activation using flow cytometry and the proteome by unbiased two-dimensional differential in-gel fluorescence electrophoresis. In total we monitored 98 surviving and 12 non-surviving COVID-19 patients over 5 days of hospital stay and compared them to healthy controls (n = 12). Results: Over the observation period the level of basal αIIbβ3 activation on platelets from non-surviving COVID-19 patients decreased compared to survivors. In line with this finding, proteomic analysis revealed a decrease in the total amount of integrin αIIb (ITGA2B), a subunit of αIIbβ3, in COVID-19 patients compared to healthy controls; the decline was even more pronounced for the non-survivors. Consumption of the fibrin-stabilizing factor coagulation factor XIIIA (F13A1) was higher in platelets from COVID-19 patients and tended to be higher in non-survivors; plasma concentrations of the latter also differed significantly. Depending on COVID-19 disease status and mortality, increased amounts of annexin A5 (ANXA5), eukaryotic initiation factor 4A-I (EIF4A1), and transaldolase (TALDO1) were found in the platelet proteome and also correlated with the nasopharyngeal viral load. Dysregulation of these proteins may play a role for virus replication. ANXA5 has also been identified as an autoantigen of the antiphospholipid syndrome, which is common in COVID-19 patients. Finally, the levels of two different protein disulfide isomerases, P4HB and PDIA6, which support thrombosis, were increased in the platelets of COVID-19 patients. Conclusion: Platelets from COVID-19 patients showed significant changes in the activation phenotype, in the processing of the final coagulation factor F13A1 and the phospholipid-binding protein ANXA5 compared to healthy subjects. Additionally, these results demonstrate specific alterations in platelets during COVID-19, which are significantly linked to fatal outcome.

Biomarkers of Thrombo-Inflammatory Responses in Pulmonary Embolism Patients With Pre-Existing Versus New-Onset Atrial Fibrillation

Pulmonary embolism (PE) patients have an increased prevalence and incidence of atrial fibrillation (AF). Because comorbid AF increases risk of morbidity and mortality, we sought to investigate the role of thrombo-inflammatory biomarkers in risk stratifying patients who experience an acute PE episode. Study participants were enrolled from a Pulmonary Embolism Response Team (PERT) registry between March 2016 and March 2019 at Loyola University Medical Center and Gottlieb Memorial Hospital. This cohort was divided into 3 groups: PE patients with a prior diagnosis of AF (n = 8), PE patients with a subsequent diagnosis of AF (n = 11), and PE patients who do not develop AF (n = 71). D-dimer, CRP, PAI-1, TAFIa, FXIIIa, A2A, MP, and TFPI were profiled using the ELISA method. All biomarkers were significantly different between controls and PE patients (P < 0.05). Furthermore, TFPI was significantly elevated in PE patients who subsequently developed AF compared to PE patients who did not develop AF (157.7 ± 19.0 ng/mL vs. 129.0 ± 9.3 ng/mL, P = 0.0386). This study suggests that thrombo-inflammatory biomarkers may be helpful in indicating an acute PE episode. Also, elevated TFPI levels may be associated with an increased risk of developing AF after a PE.

Plasma levels of von Willebrand factor and future risk of incident venous thromboembolism

Several case-control studies have reported elevated plasma von Willebrand factor (VWF) levels in patients with venous thromboembolism (VTE) compared with controls. However, because few studies have investigated the association in a prospective design, it is unclear whether elevated plasma VWF is a risk factor or a consequence of the VTE event. Therefore, we aimed to investigate the prospective association between plasma VWF levels and risk of VTE, as well as to perform subgroup analyses of deep vein thrombosis (DVT) and pulmonary embolism. We established a population-based nested case-control study of 414 VTE cases and 843 age- and sex-matched controls based on the Tromsø study cohort (1994-2007). Blood samples were collected at cohort baseline (1994-1995). Odds ratios (ORs) with 95% confidence intervals (CIs) for VTE were estimated across quartiles of VWF levels. We found that the risk of VTE increased linearly across quartiles of VWF levels (P for trend = .023). Participants with VWF in the highest quartile had an OR of 1.45 (95% CI, 1.03-2.03) for VTE compared with those in the lowest quartile. The association was strongest for unprovoked VTE (OR, 2.74; 95% CI, 1.66-4.54) and unprovoked DVT in particular (OR, 6.73; 95% CI, 3.07-14.76). Further adjustment for body mass index, C-reactive protein, hypertension, estrogen use, and smoking had a modest effect on the risk estimates. To conclude, we found a dose-dependent relationship between plasma VWF levels and future risk of incident VTE, and unprovoked events in particular. Our findings suggest that VWF may represent a promising biomarker for future risk of incident VTE.

Factor XIII and Fibrin Clot Properties in Acute Venous Thromboembolism

Coagulation factor XIII (FXIII) is converted by thrombin into its active form, FXIIIa, which crosslinks fibrin fibers, rendering clots more stable and resistant to degradation. FXIII affects fibrin clot structure and function leading to a more prothrombotic phenotype with denser networks, characterizing patients at risk of venous thromboembolism (VTE). Mechanisms regulating FXIII activation and its impact on fibrin structure in patients with acute VTE encompassing pulmonary embolism (PE) or deep vein thrombosis (DVT) are poorly elucidated. Reduced circulating FXIII levels in acute PE were reported over 20 years ago. Similar observations indicating decreased FXIII plasma activity and antigen levels have been made in acute PE and DVT with their subsequent increase after several weeks since the index event. Plasma fibrin clot proteome analysis confirms that clot-bound FXIII amounts associated with plasma FXIII activity are decreased in acute VTE. Reduced FXIII activity has been associated with impaired clot permeability and hypofibrinolysis in acute PE. The current review presents available studies on the role of FXIII in the modulation of fibrin clot properties during acute PE or DVT and following these events. Better understanding of FXIII’s involvement in the pathophysiology of acute VTE might help to improve current therapeutic strategies in patients with acute VTE.

Identification of thrombomodulin as a dynamic monitoring biomarker for deep venous thrombosis evolution

It has been demonstrated that thrombomodulin (TM) serves an important role in the formation of deep venous thrombosis (DVT) and is regarded to be a marker that can be used to measure vascular endothelial cell damage. However, how TM levels change during DVT evolution has not yet been well understood. The current study aimed to investigate the dynamic changes of TM during the evolution of DVT and explore the possible mechanisms behind these. A total of 48 patients newly diagnosed with DVT and 23 matched healthy controls were enrolled in the present study, and their plasma TM levels were examined and compared. In addition, a DVT model was established using Sprague-Dawley rats via the ‘stenosis’ method. The thrombi size, histopathologic changes and expression of TM and NF-κB in plasma and venous endothelium were measured at 9 different time points (1, 4, 6, 12 and 24 h, and at 3, 7, 14 and 21 days). Finally, the effect of inhibiting the activation of NF-κB on TM was investigated using pyrrolidine dithiocarbamate (PDTC), which is a potent inhibitor of the NF-κB pathway. The results of the current study indicated that the mean level of plasma TM in patients with DVT was significantly increased compared with healthy controls. In addition, thrombi size (clot length and weight), TM and NF-κB expression in the animal model plasma exhibited three distinct periods (1-12, 24 h-day 7 and 14-21) of markedly different results between periods. Immunofluorescence results confirmed the co-localization of TM and NF-κB in endothelial cells. In addition, it was indicated that the expression of TM in the endothelium of DVT models was upregulated compared with the control, while NF-κB was significantly downregulated. Following the administration of PDTC, the level of NF-κB and TM in the plasma were decreased significantly dose-dependently. The results of the current study suggested that TM was involved in the evolution of DVT and may be used as a dynamic biomarker to measure disease activity. Furthermore, the expression of TM during the evolution of DVT was indicated to be associated with the NF-κB signaling pathway.

Plasma fibrin clot proteomics in patients with acute pulmonary embolism: Association with clot properties

It has been reported that 476 proteins can be detected in plasma fibrin clots from patients with venous thromboembolism. Plasma fibrin clots proteomic composition in relation to their properties has not been studied in acute pulmonary embolism (PE). Clots generated from plasma of 20 PE patients and 20 healthy controls were assessed using mass spectrometry, clot permeability (K_s), and clot lysis time (CLT). The proteomic composition of plasma fibrin clots from acute PE patients differed from that of control subjects in regard to 198 clot-bound proteins. In the acute PE group, we observed increased clot-bound fibrinogen, apolipoprotein B-100, platelet glycoprotein Ib, lipopolysaccharide-binding protein, and histones H3 + 4 and reduced fibronectin, α2-antiplasmin, α2-macroglobulin, factor (F)XIII, histidine-rich glycoprotein, antithrombin, von Willebrand Factor, plasminogen, and prothrombin. Among PE patients, low K_s (≤3.83 × 10^-9 cm²) was associated with increased clot-bound C-reactive protein, kininogen-1, protein S, β-2-microglobulin, and thromboxane-A synthase when compared with patients having K_s > 3.83 × 10^-9 cm². K_s correlated inversely with FIX and FV, thrombin-activatable fibrinolysis inhibitor, complement C1s, C7, C8, and apolipoprotein A-I. The specific protein composition in plasma fibrin clots from acute PE patients is associated with denser clot formation. Several proteins unrelated to the coagulation system can modulate fibrin phenotype in acute thrombotic states. SIGNIFICANCE: Our study significantly advances the field of thrombosis and hemostasis. The plasma fibrin clot proteomics findings fill the gap of knowledge about the presence and the role of other proteins to the plasma fibrin clot in the acute phase of pulmonary embolism, aside fibrinogen, which is the main component of fibrin. The reported methodology, which involves the sample preparation using Multienzyme Digestion-Filter Aided Sample Preparation (MED FASP), data acquisition with the Quadrupole-Orbitrap mass spectrometer, and data analysis using the advanced tools such as MaxQuant, Total Protein Approach and Perseus, allows to gain not only the qualitative, but also the quantitative insights into the microworld of proteins entangled among the fibrin network. By comparing the clots formed from plasma of patients with acute pulmonary embolism with the clots from healthy control, we provide the specific protein composition associated with unfavorable clot properties observed in this disease. Moreover, our findings emphasize that several proteins unrelated to the coagulation system, can modulate fibrin phenotype in acute thrombotic states.

Pulmonary embolism location is associated with the co-existence of the deep venous thrombosis

: Multiple studies have shown that in approximately half of individuals with pulmonary embolism (PE), the deep venous thrombosis (DVT) is not evident at the moment of PE diagnosis. The underlying factors and the origin of PE in these patients are not completely understood: missed DVT, embolization of DVT in its entirety, or de-novo PE being possible explanations. The aim of this study was to evaluate the differences in PE patient with or without co-existing DVT. Sixty-three consecutive PE patients were included. Whole leg bilateral Doppler compression ultrasound was performed to all patients. The PE location and extension, C-reactive protein, platelet count, hemostatic markers FV, FVIII, FXIIIa, Fibrinogen, von Willebrand factor antigen, thrombomodulin were assessed. Thorough clinical assessment including echocardiography and pulmonary function tests were performed upon arrival and seven months later. The mean age of the patients was 57 years (SD 17.3) and 33 (52%) were women. Thirty-one patients (49.2%) had co-existing DVT. The presence of DVT was associated with the proximal location of the PE (100%), whereas none of the patients (n = 10) with exclusively peripheral PE had co-existing DVT. The PE extension, the measured hemostatic and inflammatory markers or the patient characteristics did not statistically differ between patients with isolated PE and PE with co-existing DVT. In roughly half of the PE patients no DVT could be detected. The location of the PE was associated with the presence of co-existing DVT. There were no differences in the PE extension, hemostatic markers or in the patient characteristic between patients with isolated PE or PE with co-existing DVT.