Neutrophil extracellular traps formation may be involved in the association of propranolol with the development of portal vein thrombosis.

BACKGROUND & AIMS: Nonselective ß blockers (NSBBs) facilitate the development of portal vein thrombosis (PVT) in liver cirrhosis. Considering the potential effect of NSBBs on neutrophils and neutrophil extracellular traps (NETs), we speculated that NSBBs might promote the development of PVT by stimulating neutrophils to release NETs. MATERIALS AND METHODS: Serum NETs biomarkers were measured, use of NSBBs was recorded, and PVT was evaluated in cirrhotic patients. Carbon tetrachloride and ferric chloride (FeCl3) were used to induce liver fibrosis and PVT in mice, respectively. After treatment with propranolol and DNase I, neutrophils in peripheral blood, colocalization and expression of NETs in PVT specimens, and NETs biomarkers in serum were measured. Ex vivo clots lysis analysis was performed and portal vein velocity and coagulation parameters were tested. RESULTS: Serum MPO-DNA level was significantly higher in cirrhotic patients treated with NSBBs, and serum H3Cit and MPO-DNA levels were significantly higher in those with PVT. In fibrotic mice, following treatment with propranolol, DNase I significantly shortened the time of FeCl3-induced PVT formation, lowered the peripheral blood neutrophils labelled by CD11b/Ly6G, inhibited the positive staining of H3Cit and the expression of H3Cit and MPO proteins in PVT tissues, and reduced serum nucleosome level. Furthermore, the addition of DNase I to tissue plasminogen activator (tPA) significantly accelerated clots lysis as compared with tPA alone. Propranolol reduced portal vein velocity in fibrotic mice, but did not influence coagulation parameters. CONCLUSION: Our study provides a clue to the potential impact of NETs formation on the association of NSBBs with the development of PVT.

Acute phase determinant of post-thrombotic syndrome: A review of the literature.

BACKGROUND: Post-thrombotic syndrome (PTS) is the main long-term complication of deep vein thrombosis (DVT). Several therapies are being evaluated to prevent or to treat PTS. Identifying the patients most likely to benefit from these therapies presents a significant challenge. OBJECTIVES: The objective of this review was to identify risk factors for PTS during the acute phase of DVT. ELIGIBILITY CRITERIA: We searched the PubMed and Cochrane databases for studies published between January 2000 and January 2021, including randomized clinical trials, meta-analyses, systematic reviews and observational studies. RESULTS: Risk factors for PTS such as proximal location of DVT, obesity, chronic venous disease, history of DVT are associated with higher risk of PTS. On the initial ultrasound-Doppler, a high thrombotic burden appears to be a predictor of PTS. Among the evaluated biomarkers, some inflammatory markers such as ICAM-1, MMP-1 and MMP-8 appear to be associated with a higher risk of developing PTS. Coagulation disorders are not associated with risk of developing PTS. Role of endothelial biomarkers in predicting PTS has been poorly explored. Lastly, vitamin K antagonist was associated with a higher risk of developing PTS when compared to direct oral anticoagulants and low molecular weight heparin. CONCLUSIONS: Several risk factors during the acute phase of VTE are associated with an increased risk of developing PTS. There is a high-unmet medical need to identify potential biomarkers for early detection of patients at risk of developing PTS after VTE. Inflammatory and endothelial biomarkers should be explored in larger prospective studies to identify populations that could benefit from new therapies.

Analysis of four hereditary protein C deficiencies associated with vascular thromboembolism.

OBJECTIVE: To analyze the clinical features and gene mutations in four families with hereditary protein C (PC) deficiency and explore their association with vascular thromboembolism. METHODS: The clinical data of four patients with PC deficiency were retrospectively analyzed. Venous blood samples were collected from the four affected patients and their family members, and relevant coagulation indexes and thrombin production and inhibition tests were performed. PCR was used to amplify and directly sequence the PROC gene of the probands. Software analysis was conducted to assess the conservativeness and pathogenicity of the mutated loci. Protein models were constructed to analyze the spatial structure before and after the mutation. RESULTS: Thrombin generation and inhibition assays demonstrated impaired anticoagulation in all four probands. Proband 1 and 4 presented clinically with pulmonary embolism and lower extremity deep vein thrombosis (DVT), Proband 2 with cerebral infarction, and Proband 3 with DVT. Genetic analysis revealed the presence of the following mutations: c.541T > G heterozygous missense mutation, c.577-579delAAG heterozygous deletion mutation, c.247-248insCT heterozygous insertion mutation, c.659G > A heterozygous missense mutation, and a new variant locus c.1146_1146delT heterozygous deletion mutation in the four probands, respectively. In particular, c.1146_1146delT heterozygous deletion mutations not reported previously. Conservativeness and pathogenicity analyses confirmed that most of these amino acid residues were conserved, and all the mutations were found to be pathogenic. Analysis of protein modeling revealed that these mutations induced structural alterations in the protein or led to the formation of truncated proteins. According to the American College of Medical Genetics and Genomics (ACMG) classification criteria and guidelines for genetic variants, c.1146_1146delT was rated as pathogenic (PVS1 + M2 + PM4 + PP1 + PP3 + PP4). CONCLUSION: The identified mutations are likely associated with decreased PC levels in each of the four families. The clinical manifestations of hereditary PC deficiency exhibit considerable diversity.

Mucin 1 and venous thrombosis in tumor-bearing mice and patients with cancer.

INTRODUCTION: Mucins released from epithelial tumors have been proposed to play a role in cancer-associated thrombosis. Mucin1 (MUC1) is a transmembrane mucin that is overexpressed in a variety of human malignancies, including breast and pancreatic cancer. We analyzed the association of MUC1 and venous thrombosis in a mouse tumor model and in patients with cancer. MATERIALS AND METHODS: We used a human pancreatic cancer cell line HPAF-II that expresses a high level of MUC1. We grew HPAF-II tumors in the pancreas of Crl:NU-Foxn1nu male mice. MUC1 in plasma and extracellular vesicles (EVs) isolated from plasma was measured using an enzyme-linked immunosorbent assay. MUC1 in EVs and venous thrombi from tumor-bearing mice was assessed by western blotting. We measured MUC1 in plasma from healthy controls and patients with stomach, colorectal or pancreatic cancer with or without venous thromboembolism. RESULTS AND DISCUSSION: MUC1 was detected in the plasma of mice bearing HPAF-II tumors and was associated with EVs. MUC1 was present in venous thrombi from mice bearing HFAP-II tumors. Recombinant MUC1 did not induce platelet aggregation. Levels of MUC1 were higher in patients with pancreatic cancer compared with healthy controls. In contrast to the mouse model, MUC1 was present in EV-free plasma in samples from healthy controls and patients with cancer. There was no significant difference in the levels of MUC1 in cancer patients with or without VTE. Our data did not find any evidence that MUC1 contributed to VTE in patients with cancer.

Homozygous MTHFR C677T carriers develop idiopathic portal vein thrombosis 20 years earlier than wild type.

The aim of this study was to evaluate the impact of methylene tetrahydrofolate reductase (MTHFR) rs1801133 (C→T667 transition) on age at first idiopathic portal vein thrombosis (PVT) and to identify clinical and/or laboratory variables influencing age at first PVT, including plasma homocysteine and the prothrombin rs1799963 PT (G→A transition at position 20210) (PT) mutation. A retrospective cross-sectional cohort, including 15 MTHFR TT, 32 MTHFR TC and 22 MTHFR CC idiopathic PVT participants contributing demographics, age at PVT, plasma concentrations of homocysteine and of natural anticoagulants. MTHFR TT carriers presented with a lower age at PVT than heterozygous or wild-type genotypes (31 ±â€Š8 vs. 48 ±â€Š15 vs. 52 ±â€Š13 years, P  = 0.001) and were more likely to have a plasma HC concentration above the cut-off (73.3 vs. 32 vs. 50%, P  = 0.04). MTHFR TT and protein C predicted age at PVT ( P  < 0.0001 and P  = 0.06); MTHFR TT predicted plasma homocysteine ( P  = 0.05). In the MTHFR TT group, plasma homocysteine inversely related to protein C ( P  = 0.03). Plasma homocysteine predicted the extent of PVT ( P  = 0.03). Compound MTHFR TT + PT GA did not lower age at first PVT compared to MTHFR TT alone (35 ±â€Š9 vs. 30 ±â€Š8 years). MTHFR TT is associated with a 20-year earlier PVT presentation than heterozygous and wild-type MTHFR genotypes. The inverse relation between plasma homocysteine and protein C contributes to the prematurity of PVT in the MTHFR TT group, whereas plasma homocysteine contributes to the extent of PVT. The recent exclusion of MTHFR genotyping from the thrombophilia screen needs revisiting in this setting.

Platelet factor 4 promotes deep venous thrombosis by regulating the formation of neutrophil extracellular traps.

The presence of neutrophil extracellular traps (NETs) in thrombotic diseases has been extensively studied. The exact mechanism of NET formation in deep venous thrombosis (DVT) has not been largely studied. This study is aimed to explore the role of NETs and their interaction with platelet factor 4 (PF4) in DVT. In plasma samples from 51 healthy volunteers and 52 DVT patients, NET markers and PF4 were measured using enzyme-linked immunosorbent assays (ELISA). NET generation in blood samples from healthy subjects and DVT patients was analyzed by confocal microscopy and flow cytometry. The plasma levels of NETs were significantly elevated in DVT patients, and neutrophils from patients showed a stronger ability to generate NETs after treatment. PF4 was upregulated in plasma samples from DVT patients and mediated NET formation. NETs enhanced procoagulant (PCA) via tissue factor and activating platelets to induce procoagulant activity. In addition, we established an inferior vena cava ligation (IVC) model to examine the role of NETs in thrombogenicity in DVT. In conclusion, NET formation was mediated by PF4 and enhance the procoagulant activity in DVT.

Circulating Cytokines and Venous Thromboembolism: A Bidirectional Two-Sample Mendelian Randomization Study.

BACKGROUND: Epidemiological evidence has linked circulating cytokines to venous thromboembolism (VTE). However, it remains uncertain whether these associations are causal due to confounding factors or reverse causality. We aim to explore the causality between circulating cytokines and VTE, encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE). METHODS: In the current bidirectional Mendelian randomization (MR) study, instrumental variables of 41 circulating cytokines were obtained from the genome-wide association study meta-analyses (8,293 individuals). Summary statistics for the association of VTE (17,048 cases and 325,451 controls), DVT (8,077 cases and 295,014 controls), and PE (8,170 cases and 333,487 controls) were extracted from the FinnGen Study. A multivariable MR study was conducted to adjust for potential confounders. The inverse-variance weighted method was employed as the main analysis, and comprehensive sensitivity analyses were conducted in the supplementary analyses. RESULTS: The MR analysis indicated stromal cell-derived factor-1α was suggestively associated with a reduced risk of VTE (odds ratio [OR]: 0.90; 95% confidence interval [CI]: 0.81-0.99; p = 0.033) and DVT (OR: 0.85; 95% CI: 0.75-0.97; p = 0.015). In addition, suggestive association of granulocyte colony-stimulating factor with PE (OR: 1.20; 95% CI: 1.06-1.37; p = 0.005) was observed. Multivariable MR analysis showed that the effect of cytokines on VTE was partly mediated through hemoglobin A1c and systolic blood pressure. Reverse MR analysis revealed that VTE was linked to decreased levels of several cytokines. CONCLUSION: We provide suggestive genetic evidence supporting the bidirectional causal effect between circulating cytokines and VTE, highlighting the importance of targeting circulating cytokines to reduce the incidence of VTE.

Combination of Circulating miR-125a-5p, miR-223-3p and D-dimer as a Novel Biomarker for Deep Vein Thrombosis.

BACKGROUND: Deep venous thrombosis (DVT) is a thrombus formed in the deep venous cavity and can cause a fatal pulmonary embolism. Since circulating miRNAs are used as molecular markers for the early warning and diagnosis of various diseases, such as tumors and cardiovascular diseases, the purpose of the present study was initially to identify differential expression circulating miRNAs in plasma, and then explore potential biomarkers for DVT. METHODS: The plasma of 30 patients with DVT before and after DVT-related endovascular interventions constituted 6 sample pools for miRNA sequencing, and the levels of 22 plasma miRNAs were significantly changed. Then, various bioinformatics tools were utilized to screen out 8 miRNAs with potential DVT diagnostic value. Furthermore, their diagnostic values were evaluated in 120 patients with DVT and 120 healthy individuals. RESULTS: The levels of 22 circulating plasma miRNAs (12 up-regulated, 10 down-regulated) were significantly changed in patients with DVT before and after endovascular interventions, especially miR-125a-5p (up-regulation) and miR-223-3p (down-regulation). The values of area under the ROC curve (AUC) of miR-125a-5p and miR-223-3p were both >0.8, indicating that they were valuable in diagnosing DVT. The combination of miR-125a-5p and miR-223-3p with D-dimer significantly improved the efficiency of diagnosing DVT, (AUC >0.97, the sensitivity and specificity >95%), and was better than those of D-dimer alone. CONCLUSIONS: The levels of miR-125a-5p and miR-223-3p were the most significantly changed in patients with DVT before and after endovascular interventions; together with the classic biomarker D-dimer, they can be used as a potential biomarker for diagnostic and therapeutic process of DVT.

[Predictive value of D-dimer for deep venous thrombosis of lower extremity in adult burn patients].

Objective: To investigate the predictive value of D-dimer for deep venous thrombosis (DVT) of lower extremity in adult burn patients. Methods: A retrospective case series study was conducted. The clinical data of 3 861 adult burn patients who met the inclusion criteria and were admitted to the Department of Burns of Zhengzhou First People's Hospital from January 1, 2015 to December 31, 2019 were collected. The patients were divided into DVT group (n=77) and non-DVT group (n=3 784) according to whether DVT of lower extremity occurred during hospitalization or not. Data of patients in the two groups were collected and compared, including the gender, age, total burn area, D-dimer level, with lower limb burn and inhalation injury or not on admission, with sepsis/septic shock, femoral vein indwelling central venous catheter (CVC), history of surgery, and infusion of concentrated red blood cells or not during hospitalization. Data were statistically analyzed with independent sample t test, Mann-Whitney U test, and chi-square test. The indicators with statistically significant differences between the two groups were analyzed with multivariate logistic regression analysis to screen the independent risk factors for DVT of lower extremity in 3 861 adult burn patients. The receiver operating characteristic (ROC) curve of the independent risk factors predicting DVT of lower extremity in 3 861 adult burn patients were drawn, and the area under the curve (AUC), the optimal threshold value, and the sensitivity and specificity under the optimal threshold value were calculated. The quality of the AUC was compared by Delong test, and the sensitivity and specificity under the optimal threshold value were compared using chi-square test. Results: There were no statistically significant differences in gender, occurrence of sepsis/septic shock or history of surgery during hospitalization between patients in the two groups (P>0.05), while there were statistically significant differences in age, total burn area, D-dimer level, lower limb burn and inhalation injury on admission, and femoral vein indwelling CVC and infusion of concentrated red blood cells during hospitalization between patients in the two groups (t=-8.17, with Z values of -5.04 and -10.83, respectively, χ2 values of 21.83, 5.37, 7.75, and 4.52, respectively, P<0.05 or P<0.01). Multivariate logistic regression analysis showed that age, total burn area, and D-dimer level were the independent risk factors for DVT of lower extremity in 3 861 adult burn patients (with odds ratios of 1.05, 1.02, and 1.14, respectively, 95% confidence intervals of 1.04-1.06, 1.00-1.03, and 1.10-1.20, respectively, P<0.05 or P<0.01). The AUCs of ROC of age, total burn area, and D-dimer level for predicting DVT of lower extremity in 3 861 adult burn patients were 0.74, 0.67, and 0.86, respectively (with 95% confidence intervals of 0.68-0.80, 0.60-0.74, and 0.83-0.89, respectively, P values<0.01), the optimal threshold values were 50.5 years old, 10.5% total body surface area, and 1.845 mg/L, respectively, the sensitivity under the optimal threshold values were 71.4%, 70.1%, and 87.0%, respectively, and the specificity under the optimal threshold values were 66.8%, 67.2%, and 72.9%, respectively. The AUC quality and sensitivity and specificity under the optimal threshold value of D-dimer level were significantly better than those of age (z=3.29, with χ2 values of 284.91 and 34.25, respectively, P<0.01) and total burn area (z=4.98, with χ2 values of 326.79 and 29.88, respectively, P<0.01), while the AUC quality and sensitivity and specificity under the optimal threshold values were similar between age and total burn area (P>0.05). Conclusions: D-dimer level is an independent risk factor for DVT of lower extremity in adult burn patients, its AUC quality and sensitivity and specificity under the optimal threshold value are better than those of age and total burn area, and it has good predictive value for DVT of lower extremity in adult burn patients.

Low Mean Platelet Volume is Associated with Deep Vein Thrombosis in Older Patients with Hip Fracture.

This study aimed to explore the association between mean platelet volume (MPV) and preoperative deep vein thrombosis (DVT) in older patients with hip fracture. A total of 352 consecutive older patients with hip fracture were included from January 2014 to December 2020. MPV values were measured on admission, and color Doppler ultrasonography was performed for DVT screening before the planned surgery. The receiver operating characteristic (ROC) curve was used to establish the optimal cut-off value for the prediction of DVT. Univariate and multivariate logistic regression analysis were used to examine the association between factors and DVT. The overall prevalence of preoperative DVT was 15.1%, and patients with DVT had a lower value of MPV than non-DVT patients (11.6 ± 1.2 fL vs 12.3 ± 1.4 fL, P < .01). The cut-off point according to the ROC curve for MPV was 13.3 fL, and multivariate logistic regression analysis showed that MPV level < 13.3 fL was significantly associated with an increased risk of DVT (OR = 4.857, 95% CI: 1.091-21.617, P = .038), and with every 1.0 fL decrease in MPV, the risk increased by 27.7% (OR = 1.277, 95% CI: 1.001-1.629, P = .047). Our findings indicate that a low MPV level is associated with DVT in older patients with hip fracture. As MPV is a simple indicator that can be calculated from the blood routine test, it may be a potential biomarker of DVT with the combination of other tests, further studies are needed to confirm these results.

The influence of corn trypsin inhibitor on the contribution of coagulation determinants to the Technoclone Thrombin Generation Assay (TGA) and the Calibrated Automated Thrombogram (CAT).

In thrombin generation (TG) assays, regarded as global coagulation tests, contact activation is considered a major problem which can be eliminated by adding Corn Trypsin Inhibitor (CTI). In previous studies, however, venous thrombosis risk prediction using TG assays did not improve after CTI addition. However, it is unknown whether CTI addition could help to detect subtle but relevant nuances in determinants of TG, making the assay more suitable to detect disturbances in the coagulation system. This study's objective was to assess whether the addition of CTI is associated with a broader contribution of individual coagulation factors to the total amount of thrombin formed in Calibrated Automated Thrombogram (CAT) and Technoclone Thrombin Generation Assay (TGA). Thrombin generation was measured in 326 healthy individuals from THE VTE study at very low tissue factor concentrations, with and without addition of CTI prior to blood sampling. The influence of several coagulation factors on total amount of thrombin formed, i.e. area under the curve (AUC) or endogenous thrombin potential (ETP), was analysed using multiple linear regression with standardisation of all values resulting in Z-scores with 95% confidence intervals (95%CI). Association between coagulation factors and TG changed minimally after addition of CTI. Largest changes after CTI addition were found for following factors: for CAT: free protein S (from 0.00 (95%CI -0.12 to 0.12) to -0.29 (95%CI -0.43 to -0.15)) and protein S (from -0.05 (95%CI -0.18 to 0.08) to -0.21 (95%CI -0.37 to -0.05)); for TGA: antithrombin (from -0.11 (-0.23 to 0.02) to -0.19 (-0.30 to -0.07)), factor VIII (from 0.15 (0.03 to 0.27) to 0.24 (0.13 to 0.36)) and fibrinogen (from 0.12 (-0.01 to 0.26) to 0.19 (0.06 to 0.32)). In conclusion, there is no clear trend towards a broader contribution of coagulation factors in samples handled with CTI compared with those handled without CTI.

Construction of Prediction Model of Deep Vein Thrombosis Risk after Total Knee Arthroplasty Based on XGBoost Algorithm.

OBJECTIVE: Based on the XGBoost algorithm, the prediction model of the risk of deep vein thrombosis (DVT) in patients after total knee arthroplasty (TKA) was established, and the prediction performance was compared. METHODS: A total of 100 patients with TKA from January 2019 to December 2020 were retrospectively selected as the study subjects and randomly divided into a training set (n = 60) and a test set (n = 40). The training set data was used to construct the XGBoost algorithm prediction model and to screen the predictive factors of postoperative DVT in TKA patients. The prediction effect of the model was evaluated by using the test set data. An independent sample T-test was used for comparison between groups, and the χ 2 test was used for comparison between counting data groups. RESULTS: The top five items were combined with multiple injuries (35 points), time from injury to operation (28 points), age (24 points), combined with coronary heart disease (21 points), and D-dimer 1 day after operation (16 points). In the training set, the area under the curve of the XGBoost algorithm model was 0.832 (95% CI: 0.748-0.916). CONCLUSION: The model based on the XGBoost algorithm can predict the incidence of DVT in patients after TKA with good performance.

The Impact of D-Dimer on Postoperative Deep Vein Thrombosis in Patients with Thoracolumbar Fracture Caused by High-Energy Injuries.

OBJECTIVE: To investigate the dynamic variation of D-dimer and to evaluate the efficacy and accuracy of D-dimer level in patients with thoracolumbar fractures caused by high-energy injuries. METHODS: A total of 121 patients with thoracolumbar fractures caused by high-energy injuries were retrospectively identified and included in this study. There were 83 males and 38 females, with an average age of 48.6 ± 11.2 years. All patients were treated with either screw fixation surgery or decompression fixation surgery. The D-dimer levels were measured 1 day before surgery and on the first, third, and fifth days after surgery. The dynamic variation of D-dimer and the effects of risk factors on D-dimer levels were analysed. A receiver operating characteristic (ROC) curve analysis was performed and the appropriate D-dimer cut-off level was determined for deep vein thrombosis (DVT) screening. RESULTS: Due to a trough on the third day, D-dimer levels grew in an unsustainable manner following surgery (P < 0.001). Patients with the operation time >120 min (P = 0.009) and those with an American Spinal Injury Association (ASIA) score A-C (P < 0.001) had higher D-dimer levels. The area under the curve of D-dimer was the greatest on the third day. Applying stratified cut-off values did not change the sensitivity, specificity and negative predictive value in the group with an operation time >120 min, and ASIA score A-C group. CONCLUSIONS: D-dimer levels elevated with fluctuation in patients with thoracolumbar fractures caused by high-energy injuries after surgery. Both operation time and ASIA score had an impact on D-dimer levels. Regarding DVT diagnoses, the diagnostic value of D-dimer was highest on the third day postoperatively, and stratified cut-off values by these two factors did not show better diagnostic efficacy compared with a collective one.

Diagnostic Performance of the Caprini Risk Assessment Model Combined With D-Dimer for Preoperative Deep Vein Thrombosis in Patients With Thoracolumbar Fractures Caused by High-Energy Injuries.

OBJECTIVE: To assess the validity of the Caprini risk assessment model (RAM) in risk stratification for deep vein thrombosis (DVT) and to investigate the diagnostic value of Caprini score combined with D-dimer in predicting DVT. METHODS: This study involved 429 patients with thoracolumbar fractures caused by high-energy injuries between October 2016 and November 2019. All patients were treated surgically and had a mean age of 45.3 ± 11.4 years. Patients were risk-stratified using the 2013 Caprini RAM. Mechanical and chemical prophylaxis were used for DVT. Duplex ultrasound of both lower extremities was performed before surgery. RESULTS: Of the 429 patients, 62 (14.45%) developed DVT. The incidence of preoperative DVT was correlated with Caprini score according to risk stratification(χ2 = 117.4, P < 0.001). Based on the original Caprini RAM, all the patients scored in the highest risk category (score ≥5). Further substratification showed that the majority (277 of 429, 64.57%) of the patients were in the Caprini score range 7-8 and the risk of preoperative DVT was significantly higher among patients with Caprini score >10. The area under the receiver operating characteristic curve of Caprini score and D-dimer was 0.816 and 0.769 when Caprini score >8 or D-dimer >1.81mg/L was considered the criterion of predicting the risk of DVT. When combining the 2 variables, the area under the ROC curve can increase to 0.846. CONCLUSIONS: The Caprini RAM is an effective and reliable DVT risk stratification tool in patients with thoracolumbar fractures caused by high-energy injuries. Caprini score >8 or D-dimer >1.81 mg/L may predict the occurrence of preoperative DVT and the Caprini score combined with D-dimer exhibit better diagnostic performance.

Comparison of the in vitro clot-capturing efficiencies of commercially available retrievable inferior vena cava filters.

OBJECTIVE: We compared the in vitro clot-capturing efficiencies (CCEs) of commercially available retrievable inferior vena cava (IVC) filters. METHODS: Four types of commercially available retrievable IVC filters were included in the present study: Denali (BD, Franklin Lakes, NJ), OptEase (Cordis Corp, Hialeah, Fla), Celect (Cook Medical, Bloomington, Ind), and Option (Argon Medical Devices, Frisco, Tex). The CCE of each IVC filter for 10 different size clots, ranging from 2 mm × 10 mm to 6 mm × 20 mm, was analyzed using a venous flow simulator. RESULTS: When ≥4 × 10-mm clots were used, the CCEs were 100% for all four types of IVC filters in a 20-mm-diameter simulated IVC filter. However, when ≤3 × 20-mm clots were used, the CCEs were significantly different among the four types of filters in a 20-mm-diameter simulated IVC, with the Denali showing the highest CCE, followed by the OptEase, Celect, and Option. When ≥6 × 10-mm clots were used, the CCEs were 100% for all four types of IVC filters in the 25-mm-diameter simulated IVC. However, when ≤5 × 20-mm clots were used, the CCEs were significantly different among the four types of filters in the 25-mm-diameter simulated IVC, with the Denali showing the highest CCE. When ≤5 × 10-mm clots were used, the CCEs were significantly lower in the 25-mm-diameter simulated IVC than in the 20-mm-diameter simulated IVC for all four types of IVC filters, with Option showing the greatest change in CCEs, followed by the Celect, OptEase, and Denali. CONCLUSIONS: The CCEs were significantly different among the four IVC filters and were significantly lower for the smaller size clots than for the larger size clots and for the larger diameter simulated IVC than for the smaller diameter simulated IVC.

Deep Vein Thrombosis After a Wild Bee Sting.

Allergic reactions from insect bites are mostly observed with bee stings. Bee sting reactions can be classified into 3 main headings: local, systemic, and rare reactions. Vascular thrombosis is considered both in rare and systemic reactions. The wild bee venom induces the secretion of many inflammatory mediators, including histamine, phospholipase A1, and thromboxane, leading to vasoconstriction and thrombosis. Inflammatory cytokines also cause endothelial injury and deterioration of the microcirculation. In the literature, rare reactions have been reported including various central and arterial vascular pathologies such as aortic thrombosis, cerebral infarction, and myocardial infarction; however, there is rare publication concerning peripheral deep vein thrombosis (DVT). Although DVT produces good results with effective and rapid treatment, it can be fatal because of causes such as pulmonary embolism in the absence of timely intervention. Herein, for the first time in the literature, we present a pediatric case of peripheral DVT after a wild bee sting.

The Impact of Anticoagulant Activity of Tissue Factor Pathway Inhibitor Measured by a Novel Functional Assay for Predicting Deep Venous Thrombosis in Trauma Patients: A Prospective Nested Case-Control Study.

OBJECTIVE: Deep venous thrombosis (DVT) is a common complication in patients with traumatic injury. Tissue factor pathway inhibitor (TFPI) is a natural anticoagulant protein in the extrinsic coagulation pathway. However, the relationship between DVT after trauma and the anticoagulant activity of TFPI remains unclear. In this prospective study, we investigated the role of TFPI in trauma patients with DVT to evaluate whether the anticoagulant activity of TFPI measured by a new functional assay can be used to help predict the risk of DVT. Patients and methods: This prospective nested case-control study enrolled trauma patients and healthy volunteers. Forty-eight trauma patients diagnosed with DVT and forty-eight matched trauma patients without DVT were included in the study. 120 healthy volunteers were also included as controls. Blood samples and case information were collected at admission. Patients accepted angiography before surgery to diagnose DVT. The parameters examined included TFPI anticoagulant activity, free-TFPI antigen, blood cell counts, and routine clinical coagulation tests. Results: For the parameters of TFPI anticoagulant activity, three were markedly increased in the DVT group compared to the non-DVT group (TFPI initial anticoagulant time ratio, P = .022; TFPI whole anticoagulant time ratio, P = .048; and TFPI anticoagulant rate, P = .034). The free-TFPI antigen concentration also showed a significant increasing trend in trauma patients with DVT compared with trauma patients without DVT (P = .035). Multivariate logistic regression analysis identified four independent factors for the development of DVT (TFPI initial anticoagulant time ratio, free-TFPI antigen, prothrombin time, and red blood cell count). We calculated the TFPI correlation coefficient and found that the area under the receiver operating characteristic curve was .821. Conclusions: A novel functional assay was developed to measure the anticoagulant activity of TFPI. The anticoagulant activity of TFPI can be used as a potential biomarker for diagnosing DVT in trauma patients.

Establishment of a new protein C detection system based on chromogenic substrate assay and its clinical diagnostic value for deep vein thrombosis.

BACKGROUND: Deficiency of protein C (PC) affects the balance between blood coagulation and fibrinolysis in the human body. Chromogenic-based assay is recommended as the preferred screening method for detecting PC deficiency. We established a PC detection system based on the chromogenic substrate assay. METHODS: First, a kit for the determination of PC activity in plasma was elaborately developed and its reaction parameters on XL-3200c were explored. Then, we evaluated its performance and collected specimens to compare the test results obtained with those of the Siemens detection system. Finally, the clinical diagnostic efficacy of this detection system for deep vein thrombosis (DVT) was assessed. RESULTS: Optimum conditions for PC detection were 0.25-0.1 U/ml protein C activator Protac® and 2.5-1 mM Pefachrome® PCa5297. The composition and concentration ranges of buffer substances and stabilizers in the kit were also explored. Satisfactory results were observed in performance evaluation. The test results of the newly built detection system were highly correlated with those of the Siemens detection system (R2  = 0.9771 in the control group and R2  = 0.9776 in the DVT group), and Bland-Altman plots also showed high consistency between the two detection systems. In addition, the area under the curve (AUC) of the newly built PC detection system for DVT was 0.888, indicating this system could effectively improve the diagnostic sensitivity and specificity for DVT. CONCLUSION: In this study, a sensitive, wide linear range and reliable PC activity detection system were established.

NEUT-SFL in Patients with COVID-ARDS: A Novel Biomarker for Thrombotic Events?

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an enveloped RNA virus first identified in December 2019 in Wuhan, China, and responsible for coronavirus disease 2019 (COVID-19). The ongoing COVID-19 pandemic is impacting healthcare worldwide. Patients who develop coagulopathy have worse outcomes. The pathophysiology of COVID-19 suggests a strong interplay between hemostasis and immune cells, especially neutrophils. Our purpose was to assess neutrophil fluorescence as a potential biomarker of deep vein thrombosis (DVT) in patients with COVID-acute respiratory distress syndrome (COVID-ARDS). Sixty-one patients with COVID-ARDS admitted to the four intensive care units (ICUs) of a French general hospital were included in this prospective study. Neutrophil activation was assessed by measuring neutrophil fluorescence (NEUT-Side Fluorescence Light, NEUT-SFL) with a specific fluorescent dye staining analyzed by a routine automated flow cytometer Sysmex XN-3000™ (Sysmex, Kobe, Japan). DVT was diagnosed by complete duplex ultrasound (CDU). We found that NEUT-SFL was elevated on admission in patients with COVID-ARDS (49.76 AU, reference value 46.40 AU, p < 0.001), but did not differ between patients with DVT (49.99 AU) and those without (49.52 AU, p = 0.555). NEUT-SFL is elevated in patients with COVID-ARDS, reflecting neutrophil activation, but cannot be used as a marker of thrombosis. Because neutrophils are at interface between immune response and hemostasis through release of neutrophil extracellular traps, monitoring their activation could be an interesting approach to improve our management of coagulopathy during COVID-ARDS. Further research is needed to better understand the pathophysiology of COVID-19 and identify high-performance biomarkers.

Correlation between serum factor VIII:C levels and deep vein thrombosis following gynecological surgery.

Deep vein thrombosis (DVT) is common in patients following gynecological surgery. Coagulation factor VIII (FVIII) is an important part of the human coagulation system, and FVIII:C is a component of FVIII with anticoagulant activity. 800 patients who underwent gynecological surgery were enrolled. General clinical data were harvested, and pre - and postoperative serum FVIII levels were determined. Lower-extremity ultrasound examination and/or postoperative pulmonary angiography were performed. Related data were analyzed statistically. DVT was the first manifestation of venous thromboembolism in all cases. There were a total of 46 cases, and the incidence of DVT was 5.8%. Progression to pulmonary embolism was confirmed in 16 cases, with an incidence of 2.0%. The independent risk factors for DVT after gynecological surgery were postoperative FVIII:C levels (odds ratio [OR] = 1.01), age (OR = 6.57), and operation time ≥3 hours (OR = 2.90) (P < 0.05). When the FVIII:C level was greater than the 75th centile (≥150 IU/dL), the risk of DVT was 2.99 times higher than that below the 25th centile (<100 IU/dL) (P < 0.05). When combined with the risk factor of operation time ≥3 hours, the risk increased to 3.17 times (P = 0.10). When combined with age ≥60 years, the risk was significantly increased, reaching 12.0 times (P < 0.05). Serum FVIII:C levels are an independent risk factor for DVT after gynecological surgery. Higher levels increase the risk of DVT after gynecological surgery, and they may have a dose-dependent relationship. A synergistic effect exists in combination with other risk factors, which further increases the risk.