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Preeclampsia is a worldwide contributor to maternal and fetal morbidity and mortality. Women with preeclampsia are in a hyper-coagulable state with increased risk of thromboembolic disease later in life compared with normal pregnant women. The contact system (CAS) in plasma can mediate thrombin generation and is an important contributor to thrombus growth, but the activation of CAS during pregnancy complicated by preeclampsia is not yet elucidated, and CAS may play a role in the pathophysiology of preeclampsia. Therefore, the aim of the study is to address thrombin generation, and in particular, the capacity of the CAS-mediated pathway in patients with preeclampsia compared with pregnant controls. One hundred and seventeen women with preeclampsia and matched controls were included. The project was registered at www.clinicaltrials.gov as NCT04825145. CAS and tissue factor induced thrombin generation, proteins C and S, antithrombin, and histidine-rich glycoprotein (HRG) were assessed. Women with preeclampsia had significantly increased CAS and tissue factor-induced endogenous thrombin potential (ETP), and HRG compared with controls, P  = 0.022, P  = 0.024, and P  = 0.02, respectively. The concentrations of protein C and antithrombin were significantly reduced in the preeclampsia group, P  = 0.024 and P  < 0.0001, respectively. No significant difference in the concentration of protein S was detected, P  = 0.06. This study demonstrates a significant increased CAS-induced ETP and an overall decrease of important regulators of coagulation in women with preeclampsia compared with controls. These aspects can contribute to the hyper-coagulable state characterizing preeclampsia., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The contact system (CAS) is part of the coagulation system, consisting of a group of plasma proteins stimulating inflammation, coagulation, and fibrinolysis when activated. CAS can be triggered by several activating surfaces, and CAS may play a potential role in thrombus formation. Combined oral contraceptives (COCs) are known to increase the risk of venous thromboembolism, and COCs induce various prothrombotic changes in the coagulation system, whereas the effect of COC on CAS has not been thoroughly investigated., Objectives: To investigate CAS in COC users compared with nonusers., Methods: Blood samples from 62 study subjects, 30 COC users, and 32 nonusers, were analyzed. Coagulation factor XII (FXII), prekallikrein (PK), H-Kininogen (HK), cleaved HK (cHK), C1-esterase inhibitor (C1-inh), and the endogenous kallikrein potential (EKP) were measured., Results: COC users had significantly higher FXII (median, 38.4 vs 28.9 mg/L) and lower C1-inh levels (0.20 vs 0.23 g/L) than nonusers. The levels of PK and HK were not significantly different. Measurement of EKP indicated an increased capacity of CAS in COC users (1860 vs 1500 nmol/L × min), and increased plasma levels of cHK (2.02 vs 1.07 μg/L) indicated an increased activity in vivo ., Conclusion: This study demonstrates an increased CAS capacity in women using COC compared with nonusers and also an increased activity in vivo . The results indicate that increased contact activation may contribute to the increased thrombotic risk caused by COC., (© 2023 The Authors.)

Introduction: Hypogonadism is prevalent during opioid treatment, and low testosterone concentrations are associated with cardiovascular disease. The effect of testosterone replacement therapy (TRT) on the coagulation system in men with hypogonadism is not clarified. We investigate the effects of TRT on the tissue factor (TF) and contact activation pathways of coagulation in opioid-treated men., Materials and Methods: This was a double-blinded, placebo-controlled study in 37 men with total testosterone < 12 nmol/L randomized to 24 weeks of testosterone injections (n = 17) or placebo (n = 20). Variables of the coagulation system were analysed at baseline and after 24 weeks. Measurements included the TF pathway (endogenous thrombin potential (ETP) and peak thrombin), the contact activation pathway (endogenous kallikrein potential (EKP) and peak kallikrein), coagulation factors (FVII, FX, prothrombin, and FXII), and inhibitors (tissue factor pathway inhibitor (TFPI), protein C, protein S, antithrombin, and C1 esterase inhibitor (C1inh)). Between-group differences at 24 weeks were determined with analysis of covariance. Within-group changes in TRT and placebo were analysed with paired t-test., Results: Between-group differences at 24 weeks were observed for ETP (P = 0.036), FVII (P = 0.044), FX (P = 0.015), prothrombin (P = 0.003), protein C (P = 0.004), and protein S (P = 0.038). Within the TRT group, ETP, peak thrombin, FVII, FX, prothrombin, TFPI, protein C, FXII, and C1inh decreased and protein S increased (all P < 0.05). Within the placebo group, coagulation outcomes were unchanged., Conclusion: TRT affects the coagulation system in an anticoagulant direction through suppressed TF pathway in men with opioid-induced hypogonadism.

Background: Direct oral anticoagulants (DOACs) are the first-choice treatment option for the prevention of the recurrence of venous thrombosis in patients with pulmonary embolism (PE); however, their effect in patients with antiphospholipid syndrome (APS) is challenged. Therefore, the prevalence of antiphospholipid autoantibodies in patients with PE is noteworthy., Objectives: To determine the prevalence of unselected patients presenting with PE who meet the criteria for APS based on elevated levels of anticardiolipin (aCL) and anti-β2-glycoprotein I (aβ2GPI) antibodies., Methods: Consecutive patients with PE, in whom DOACs were primarily initiated, were tested for aCL and aβ2GPI. If the levels were elevated, the tests were repeated after 12 weeks for APS diagnosis. Laboratory results and patient characteristics were retrospectively collected from a laboratory information system and electronic patient journal entries over a 2-year period., Results: The prevalence of APS based on consistently elevated levels of aCL or aβ2GPI was 3.7% (10 of 267 patients). Three patients were double positive. In 11 out of 21 patients (52%) with initially elevated values, the levels of the antibodies normalized after 12 weeks. The patient characteristics were largely similar in those with APS and those without APS; however, patients with APS tended to be older and more likely to receive antithrombotic treatment at the time of PE., Conclusion: We found a relatively low prevalence of APS based on aCL or aβ2GPI. The high rate of normalized levels of the antibodies after 12 weeks reaffirms the need for repeated tests for APS diagnosis. Older patients more frequently met the criteria for APS. Determining the effectiveness of DOACs in non-triple-positive patients with APS following venous thromboembolism is important to further determine the feasibility of unselected tests in patients with PE., (© 2023 The Author(s).)

Objective: The pathophysiology of preeclampsia is not fully understood. Disturbances in the contact system are associated with preeclampsia. Few studies have investigated the association between preeclampsia and alterations in the contact system in plasma. This study aims to elucidate whether this basic biological system is affected in preeclampsia using new methods focusing on the dynamic interactions and total capacity of the contact system in blood., Design: Cross-sectional study matching women with preeclampsia and controls without preeclampsia regarding age, pregestational body mass index, and gestational age at onset of the disease., Setting: Two Danish University hospitals., Sample: A cohort of 117 women with preeclampsia and 117 controls., Methods: The turnover and capacity of the contact system were determined with new methods. Paired t -test, Wilcoxon signed-pairs signed rank test, Mann-Whitney or Chi 2 -test were applied, as appropriate., Main Outcome Measurements: Kallikrein generation (peak kallikrein concentration and endogenous kallikrein potential), coagulation factor XII, prekallikrein, H-kininogen, cleaved H-kininogen, and complement C1 esterase inhibitor., Results: The endogenous kallikrein potential, peak kallikrein concentration, prekallikrein and cleaved H-kininogen were significantly lower in women with preeclampsia compared to the controls, p ≤ 0.005, whereas the concentration of coagulation factor XII, H-kininogen and complement C1 esterase inhibitor was not significantly different, p > 0.05., Conclusion: This study demonstrates significant reduction in kallikrein generating capacity, prekallikrein and cleaved H-kininogen indicating that the contact system is affected in preeclampsia suggesting a link to the pathophysiology of the disease., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Godtfredsen, Gram, Pham, Dolleris, Jørgensen, Sidelmann and Palarasah.)

Objectives: The contact system consists of coagulation factor XII (FXII), prekallikrein, and H-kininogen (HK) and plays important roles in many diseases. Plasma kallikrein (PKa) cleaved HK (cHK) is a marker of contact activation. Presently, we developed a specific and precise enzyme-linked immunosorbent assay (ELISA) for determination of cHK in vitro and ex vivo., Methods: Cleaved HK specific mouse monoclonal antibodies (mAbs) were generated using a peptide corresponding to the PKa cleavage site on HK as immunogen. ELISA, surface plasmon resonance analysis, and immunoprecipitation established the specificity of the antibody, which subsequently was used in a sandwich ELISA. The analytical imprecision and the concentration of cHK in a reference population and in women receiving oral contraceptives (OC) were determined. cHK was assessed in vitro in plasma exposed to polytetrafluoroethylene, silicone, and glass tubes., Results: The selected mAb showed excellent specificity towards cHK. The intra-assay and inter-assay CV of the ELISA were 3.6 and 6.0%, respectively. The reference population (60 women, 60 men) displayed a median cHK plasma concentration of 1.38 μg/mL and a reference interval of 0.82 - 2.56 μg/mL. Women receiving OC had significantly higher concentrations, p < 0.001. cHK was significantly elevated in plasma exposed to polytetrafluoroethylene, p = 0.001, and glass, p < 0.0001., Conclusion: The ELISA showed excellent precision and specificity. cHK assessment ex vivo demonstrated ongoing contact activation in healthy individuals, augmented by OC. The cHK antibody and the ELISA could be promising tools in contact activation related diseases and in vitro investigations of the plasma compatibility of blood contacting biomaterials., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Palarasah, Pham, Gram, Graversen, Pilely and Sidelmann.)

Objectives: Preeclampsia (PE) is a serious complication of pregnancy. The fibrinolytic system play crucial roles regarding placentation and evolution of PE., Aim: To study comprehensively components of the fibrinolytic system and fibrin lysability in women with PE., Design and Methods: 117 women with PE and matched controls were included. Tissue type plasminogen activator (t-PA), plasminogen, PAI-1, plasmin inhibitor (PI), D-dimer, the fibrinolytic potential of dextran sulphate euglobulin fraction (DEF), PAI-2, polymere PAI-2, fibrin clot lysability, thrombin activatable fibrinolysis inhibitor (TAFI) and fibrinogen were assessed., Results: Women with PE had significantly increased concentrations of t-PA and PAI-1, whereas the plasma concentration of PAI-2 was significantly lower compared to controls, p < 0.0001. Polymere PAI-2 was detected in both groups. DEF, TAFI and fibrinogen were not different between the groups. D-dimer was significantly increased and plasminogen/PI together with fibrin clot lysability time decreased in the PE-group, p  =  0.0004 p  =  0.04, p  =  0.03, p < 0.0001 respectively., Conclusion: This study demonstrates that PE is associated with an affected t-PA/PAI-1 system, decreased PAI-2 and increased fibrin lysability. Furthermore, PAI-2 has the potential to polymerize during pregnancy.

Background: Prothrombotic and inflammatory variables decrease after obesity surgery. The contact activation system may be a common denominator of these changes., Objective: To characterize the contact system before and 6 months after Roux-en-Y gastric bypass (RYGB) and to evaluate associations with changes (post-surgery minus pre-surgery) in metabolic variables., Methods: Women (n = 42) and men (n = 18) with obesity underwent RYGB, and measures of kallikrein generation, factor XII (FXII), prekallikrein, high molecular weight kininogen (HK), and C1 esterase inhibitor (C1-inh) were determined before and 6 months after surgery. Associations were evaluated using correlation and multivariate regression analyses., Results: After RYGB, the endogenous kallikrein potential (EKP), peak kallikrein generation, FXII, and prekallikrein were reduced, and kallikrein generation lag time was prolonged (all p < 0.0005). Before and after RYGB, absolute values of EKP, lag time, and peak kallikrein generation correlated consistently with contact system proteins (range of correlation coefficients (r S ): -0.43 to -0.28 and 0.24 to 0.45 (pre-surgery); -0.43 to -0.30 and 0.28 to 0.50 (post-surgery)). RYGB-associated changes in EKP correlated with C1-inh (r S  = -0.29, p = 0.025), but also with triglycerides (r S  = 0.34, p = 0.007) and cholesterol (r S  = 0.28, p = 0.029), and independently associated with changes in C1-inh (β = -0.40) and triglycerides (β = 0.39). Changes in C1-inh associated with reductions in body weight (β = -0.39) and HbA1c (β = 0.38)., Conclusion: The contact system was affected 6 months after RYGB. Absolute values of kallikrein generation before and after RYGB correlated with contact system proteins, whereas changes after RYGB associated with changes in C1-inh and metabolic variables., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The effect of anabolic-androgenic steroid (AAS) abuse on the contact activation system (CAS) is not known in detail. We hypothesized that current AAS abuse reduces the kallikrein-generating capacity of CAS significantly and investigated the impact of AAS on the proteins and capacity of CAS in current and former AAS abusers and healthy age-matched controls. Men 18 to 50 years of age were included as current AAS abusers, former AAS abusers, or controls. Blood samples were collected after overnight fasting. Kallikrein generation (lag time, peak height, and endogenous kallikrein potential [EKP]), coagulation factor XII (FXII), prekallikrein, high-molecular-weight kininogen (HK), and Complement C1 esterase inhibitor (C1inh) were assessed. Groups were compared by analysis of variance or Kruskal-Wallis test and probabilities were corrected for multiple comparisons. Associations were evaluated by linear regression models. The EKP was significantly reduced in current ( n  = 37) AAS abusers (984 ± 328 nmol/L × min) compared with former ( n  = 33) abusers (1,543 ± 481 nmol/L × min) and controls ( n  = 30) (1,521 ± 339 nmol/L × min), p  < 0.001. Current abusers had higher levels of FXII and C1inh and lower levels of prekallikrein and HK than controls, p ≤ 0.025. Stepwise regression analysis showed that EKP was associated with C1inh and prekallikrein in current AAS abusers, R 2  = 0.70, p  < 0.001. We conclude that current AAS abuse reduces the kallikrein-generating capacity of CAS by increasing the concentration of C1inh and reducing the concentration of prekallikrein. These changes may contribute to the anti-inflammatory effect of testosterone., Competing Interests: None declared., (Thieme. All rights reserved.)

Abuse of anabolic-androgenic steroids (AASs) is suspected to increase the risk of cardiovascular disease (CVD) and cardiovascular mortality in otherwise healthy individuals. AAS abuse may increase the incidence of CVD by altering the hemostatic balance toward a procoagulant state. Studies on the effect of AAS abuse on the fibrinolytic system, however, have either demonstrated a profibrinolytic effect or no effect of AAS abuse, but the overall effect of AAS on fibrinolysis has not been addressed so far. This cross-sectional study investigated the effect of AAS on fibrin clot lysis, fibrin structure, and the hemostatic proteins, potentially affecting these measures in current and former AAS abusers and healthy age-matched controls. The study population consisted of 37 current and 33 former AAS abusers, along with 30 healthy age-matched controls. Fibrin clot lysis, fibrin structure properties, fibrinogen, coagulation factor XIII (FXIII) plasminogen, plasmin inhibitor, plasminogen activator inhibitor-1 (PAI-1), and thrombin activatable fibrinolysis inhibitor (TAFI) were determined. Fibrin clot lysis was significantly reduced in participants abusing AAS compared with former abusers and controls ( p  < 0.001). Plasma fibrinogen, plasminogen, and plasmin inhibitor were significantly increased in current abusers ( p  < 0.05). No significant differences were observed with respect to measures of fibrin structure properties, PAI-1, and TAFI ( p  > 0.05). In conclusion, AAS abuse depresses fibrin clot lysis. This effect is not associated with alterations in fibrin structure but is rather caused by increased plasma concentrations of fibrinogen, FXIII, and plasmin inhibitor. These findings suggest that AAS abuse may be associated with increased thrombotic disease., Competing Interests: None declared., (Thieme. All rights reserved.)

Introduction: Polycystic ovary syndrome (PCOS) is characterized by increased central fat mass (CFM), hyper-inflammation, and hemostatic alterations; the risk of cardiovascular disease may also be increased. Reduced fibrin lysability is a risk factor for cardiovascular disease. The present study assessed fibrin lysability in women with PCOS and controls of similar age and body mass index., Material and Methods: Ninety women with PCOS and 35 controls of comparable age and body mass index were included. Hemostatic markers (fibrin lysability, fibrinogen, coagulation factor XIII, plasminogen, plasminogen activator inhibitor 1 [PAI-1], plasmin inhibitor, thrombin activatable fibrinolysis inhibitor (TAFI), D-dimer), C-reactive protein (CRP), body mass index, waist-to-hip ratio, CFM determined by Dual-energy X-ray absorptiometry scan, and sex hormones (testosterone estradiol, and sex hormone binding globulin) were determined., Results: TAFI and CRP were higher in women with PCOS, than controls. In women with PCOS, fibrin lysability correlated with CFM, waist-to-hip ratio, CRP, fibrinogen, and all hemostatic variables (P ≤ .004) except TAFI and D-dimer. CFM correlated with fibrinogen, CRP, coagulation factor XIII, waist-to-hip ratio, plasminogen, PAI-1, plasmin inhibitor, and TAFI (P < .02). In controls, fibrin lysability correlated with CFM, fibrinogen, coagulation factor XIII, and plasmin inhibitor (P ≤ .02). CFM correlated with PAI-1, plasmin inhibitor, coagulation factor XIII, fibrinogen, and CRP (P ≤ .05). Stepwise regression analysis revealed that fibrin lysability was associated with CFM, fibrinogen and CRP in women with PCOS (r 2  = .46, P ≤ .001), but only with CFM in controls (r 2  = .28, P < .001)., Conclusions: Fibrin lysability was comparable in women with PCOS and controls. Fibrin lysability was associated with CFM and hyper-inflammation in women with PCOS, but only with CFM in controls. These findings suggest that obese women with PCOS and augmented inflammation could have an increased risk of cardiovascular disease., (© 2020 Nordic Federation of Societies of Obstetrics and Gynecology.)

Purpose: Little is known of the systemic effects of oral and maxillofacial surgery on the hemostatic balance, including the biochemical effects of tranexamic acid (TXA), on fibrin clot lysis. The present study investigated the effects of orthognathic surgery on fibrin lysis, fibrin structure, and D-dimer and evaluated the effect of TXA on these fibrinolytic measures., Materials and Methods: The present double-blind, controlled, and randomized, placebo study included patients referred to the Department of Oral and Maxillofacial Surgery at the University Hospital of Southern Denmark-Esbjerg from August 2014 through September 2016. The patients were elective and had a diagnosis of maxillary or mandibular deficiency, either excessive or asymmetric. All patients underwent bimaxillary orthognathic surgery (OS) with or without maxillary segmentation or additional genioplasty. The patients were blindly randomized to treatment with TXA or placebo. The primary predictor variable was OS. The secondary predictor variable was an intravenous dose of 1 g of TXA or equivalent placebo preoperatively. Blood samples were collected before surgery and 5 hours after the initiation of surgery. The primary outcome variable was lysis of fibrin. The fibrin structure properties and D-dimer were secondary outcome measures. The Mann-Whitney U test was used for the within-group comparisons. The Wilcoxon signed rank test was used for the between-group comparisons., Results: The sample included 96 patients; 45 received placebo and 51 received TXA. Fibrin lysis decreased after OS (P < .001). The fibrinolytic shutdown decreased significantly more in the TXA group than in the placebo group (P < .001). OS altered the fibrin structure properties with comparable effects in the 2 groups. D-dimer increased postoperatively but significantly less so in the TXA group than in the control group (P < .001)., Conclusions: OS is associated with fibrinolytic shutdown and alters fibrin structure properties, driving the hemostatic balance in a prothrombotic direction. The fibrinolytic shutdown is significantly amplified by TXA., (Copyright © 2020. Published by Elsevier Inc.)

Background: The complement and coagulation systems share an evolutionary origin with many components showing structural homology. Certain components, including complement factor H (FH) and coagulation factor XII (FXII), have separately been shown to have auxiliary activities across the two systems., Objectives: The interaction between FXII and FH was investigated., Methods: Using enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR) complex formation between different FXII forms and FH was investigated. The presence of α-FXIIa:FH complexes upon contact activation in plasma was evaluated by ELISA and immunoprecipitation., Results: We identified and characterized a direct interaction between the components and demonstrated that among different forms of FXII, only the activated α-FXIIa formed complexes with FH, with an apparent binding strength K d of 34 ± 9 nmol/L. The complex formation involved the kringle domain of the heavy chain of FXII. C1-inhibitor induced inhibition of α-FXIIa did not alter the binding of α-FXIIa toward FH. We further demonstrated the presence of α-FXIIa:FH complexes in normal human plasma upon contact activation, indicating formation of α-FXIIa:FH complexes as a consequence of α-FXIIa generation. Complex formation between α-FXIIa and FH was also assessed in hereditary angioedema (HAE) patients with C1-inhibitor deficiency as well as rheumatoid arthritis (RA) patients with high levels of anti-cyclic citrullinated peptide (anti-CCP) upon contact activation. We observed elevated levels of α-FXIIa:FH complexes in HAE patients, and equal levels of complexes in RA patients and healthy individuals upon contact activation., Conclusion: A direct interaction between α-FXIIa and FH is demonstrated. Our findings represent a new crosstalk between these systems, potentially important in the onset and pathology of inflammatory vascular diseases., (© 2020 International Society on Thrombosis and Haemostasis.)

Objectives: To describe carotid plaque composition by computed tomography angiography (CTA) in asymptomatic subjects and to compare this to carotid plaque assessment by ultrasound, coronary plaques by coronary CTA, and inflammatory biomarkers in plasma., Methods: Middle-aged asymptomatic men, n = 43, without known cardiovascular disease and diabetes were included. Plaques in coronary and carotid arteries were evaluated using CTA. Total plaque volumes and plaque composition were assessed by a validated plaque analysis software. The 60% centile cut point was used to divide the population into low or high carotid total plaque volumes. The occurrence of carotid plaques and intima-media thickness (IMT) was estimated by ultrasound., Results: Carotid plaque by ultrasound was undiagnosed in 13 of 28 participants (46%) compared to CTA. Participants having carotid plaques by ultrasound had significantly higher absolute volumes of all CTA-defined carotid plaque subtypes and a higher fraction of calcified plaque. A high carotid total plaque volume was independently associated with age (adjusted odds ratio (OR) 1.41 [95% confidence interval (CI) 1.14-1.74], p = 0.001), IMT (adjusted OR 2.26 [95% CI 1.10-4.65], p = 0.03), and D-dimer (adjusted OR 8.86 [95% CI 1.26-62.37], p = 0.03). All coronary plaque features were significantly higher in participants with a high carotid total plaque volume., Conclusion: The occurrence of carotid plaques in asymptomatic individuals is underestimated by ultrasound compared to plaque assessment by CTA. Carotid plaque composition by CTA is different in individuals with and without carotid plaques by ultrasound., Key Points: • The occurrence of carotid plaques by ultrasound was underestimated in 46% of participants who had plaques by carotid CTA. • Participants with carotid plaques by ultrasound had higher volumes of all plaque subtypes and a higher calcified plaque component as determined by carotid CTA compared to participants without carotid plaques by ultrasound. • A high carotid total plaque volume was independently associated with age, intima-media thickness, and D-dimer.

Introduction: Fibrin clot lysability is associated with development of cardiovascular disease (CVD). We evaluated sex-differences in fibrin clot lysability and the association with coronary plaque composition determined by computed tomography angiography (CTA)., Methods: Middle-aged citizens without known CVD were randomly selected from a national registry. A coronary CTA assessed volumes of calcified-, non-calcified-, low-density non-calcified-, and total- plaque using a validated plaque quantification software. A non-enhanced cardiac CT scan assessed the Agatston score. Fibrin structure properties were determined using turbidimetric methods. Plasma concentrations of C-reactive protein and fibrinogen were assessed., Results: 138 individuals (71 women) participated. Men more frequently had coronary plaques compared to women, P < 0.05. Coronary plaque features were comparable between men and women, P > 0.05. Women with total plaque volume > 0 mm 3 had lower fibrin clot lysability compared to women with total plaque volume = 0 mm 3 , adjusted difference [95% confidence interval] 10.28 [1.42-19.15], P = 0.02, and a fibrinogen-dependent lower fibrin clot lysability compared to men with and without coronary plaques, 6.82 [-2.67-16.31], P = 0.16, and 8.73 [-0.43-17.89], P = 0.06, respectively. Fibrinogen correlated with all the coronary plaque features (correlation coefficient r = 0.42-0.57) only in women with total plaque volume > 0 mm 3 , all P < 0.01., Conclusion: Asymptomatic women with coronary plaques assessed by coronary CTA have reduced fibrin clot lysability compared to both women without coronary plaques and men, suggesting a sex-dependent link between coronary atherosclerosis and fibrin clot lysability., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background Phadia/EliA fluorescence enzyme immunoassays are widely used automated assays for anticardiolipin (aCL) and anti-β2-glycoprotein I (aβ2GPI) antibodies. To date, cut-off values for these assays have not been evaluated systematically and the evidence behind manufacturer's recommended cut-off values is not clear. Objective To determine Phadia/EliA cut-off values for antiphospholipid antibodies (aPL) according to the procedures suggested by guidelines. Methods A total of 266 blood donors (135 females and 131 males) were included. The pre-handling and analysis of the samples were performed according to the International Society on Thrombosis and Hemostasis (ISTH) guideline for solid phase aPL assays. Cut-off values and corresponding 90% confidence intervals (CI) for each antibody were established and outliers were handled according to the Clinical and Laboratory Standards Institute (CLSI) guideline for reference intervals. Samples from 377 consecutive patients, referred to our thrombophilia center with evidence of thrombosis or pregnancy morbidity were included for aPL testing. Results The in-house 99th (97.5th) percentile cut-off values were 11 (8.7), 12 (6.9) 8.5 (5.0) AU/mL for aβ2GPI IgG, IgM and IgA, and 21 (13) GPL-U/mL and 41 (25) MPL-U/mL for aCL IgG and IgM, respectively. The prevalence of positive results (%) defined by these cut-off values in patients with evidence of thrombosis or pregnancy morbidity was 9.5 (12.2), 1.6 (2.9), and 7.0 (9.9), and 0.8 (3.8) for aβ2GPI IgG, IgM, and aCL IgG and IgM respectively. The use of in-house 99th percentile cut-off values compared to the manufacturer suggested cut-off values resulted in 1 and 39 fewer samples for aβ2GPI and aCL to be classified as positive for aPL, respectively. Conclusions We present Phadia/EliA cut-off values with 90% CI for aPL determined systematically according to the ISTH and CLSI guidelines. These values are different from values previously determined, suggesting variation of aPLs in different populations. Our findings indicate the need for each laboratory to determine/validate assay specific cut-off values for aPL.

Background: Incidence and prevalence of cardiovascular disease (CVD) differ between sexes, and women experience CVD later than men. Changes in fibrin clot lysability are associated with CVD, and the present study addresses sex differences in fibrin clot lysability in asymptomatic middle-aged individuals and the relation to coronary artery calcification (CAC)., Methods: Participants free of morbidities and medication, N = 163, were randomly chosen from a national registry among citizens, 50 or 60 years of age, and were followed for 5 years. CAC was determined by the Agatston (Ag) score both at baseline and at follow-up. Based on the changes in Ag, the population was divided into two groups: ΔAg = 0 U or ΔAg > 0 U. Fibrin clot analyses were based on turbidimetric methods., Results: At baseline, 116 women and 97 men were included; 84 women and 79 men completed the 5-year follow-up (77%). Independently of covariates, women with ΔAg > 0 had reduced mean (SD) fibrin lysability at follow-up, 40.2% (15.9), both in comparison to baseline, 47.8% (20.4), p = 0.001, to women with ΔAg = 0 U, 51.2% (24.5), p = 0.028, and to men with ΔAg > 0 U, 54.4% (21.0), p = 0.002., Conclusions: Fibrin clot lysability changes over time with considerable sex differences. Women with progression of CAC have reduced fibrin clot lysability compared to men, indicating a sex-specific association between morphological vessel wall changes and fibrin clot lysability.

Objectives: Investigation of the blood compatibility requires a number of sensitive assays to quantify the activation of the blood protein cascades and cells induced by biomaterials. A global assay measuring the blood compatibility of biomaterials could be a valuable tool in such regard. In this study, we investigated whether an enzyme-linked immunosorbent assay (ELISA), that specifically measures the electrophoretic "fast form" of α 2 -macroglobulin (F-α 2 M), could be a sensitive and global marker for activation of calcium dependent and in-dependent proteases in plasma exposed to biomaterials in vitro., Methods: A F-α 2 M specific monoclonal antibody was generated and applied in an ELISA setup. Using the F-α 2 M ELISA, we investigated activation of calcium dependent and in-dependent proteases by polyvinylchloride (n=10), polytetrafluoroethylene (n=10) and silicone (n=10) tubings as well as glass tubes (n=10)., Results: We found that F-α 2 M is a sensitive marker for activation of both calcium dependent and in-dependent proteases. A significant difference between F-α 2 M concentrations in the control sample and plasma exposed to the artificial surfaces was found (p>0.001). This was observed both in the presence and absence of calcium. Furthermore, the highest F-α 2 M concentration was in both cases found in plasma incubated with glass., Conclusions: Our findings demonstrate that F-α 2 M is a sensitive marker for detection of protease activation in plasma by artificial surfaces. Potentially, levels of F-α 2 M could be a global marker of the blood compatibility of biomaterials., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: The purposes of this study were to compare the presence, extent and composition of coronary plaques in asymptomatic patients with newly diagnosed type 2 diabetes to age- and sex-matched controls., Methods: Patients with newly diagnosed (<1 year) type 2 diabetes ( n = 44) and controls ( n = 44) underwent contrast-enhanced coronary computed tomography angiography. Advanced plaque analysis including total plaque volume and volumes of plaque components (calcified plaque and non-calcified plaque, including low-attenuation [low-density non-calcified plaque]) was performed using validated semi-automated software., Results: Coronary artery calcification was more often seen in patients with type 2 diabetes (66%) versus controls (48%), p < 0.05. Both the absolute volume (median; interquartile range) of low-density non-calcified plaque (7.9 mm 3 ; 0-50.5 mm 3 vs 0; 0-34.3 mm 3 , p < 0.05) and the increase in low-density non-calcified plaque ratio in relation to total plaque volume ( τ = 0.5, p < 0.001) were significantly higher in patients with type 2 diabetes. More patients with type 2 diabetes had spotty calcification (31% vs 0%, p < 0.05). By multivariate analysis, the presence of any low-density non-calcified plaque was higher in males (odds ratio: 4.06, p < 0.05), who also demonstrated a larger low-density non-calcified plaque volume ( p < 0.001). The presence and extent of low-density non-calcified plaque increased with age, smoking, hypertension and hyperglycaemia, all p < 0.05., Conclusion: Asymptomatic patients with newly diagnosed type 2 diabetes had plaque features associated with increased vulnerability as compared with age- and sex-matched controls.

: Factor VII-activating protease (FSAP) may regulate development of cardiovascular disease (CVD). We evaluated sex differences in FSAP measures and examined the association between FSAP and coronary artery calcification (CAC) in a middle-aged population. Participants were randomly selected citizens aged 50 or 60 without CVD, diabetes mellitus, Marburg I polymorphism, or hormone replacement therapy (HRT). FSAP protein concentration (total FSAP), FSAP urokinase-activating capacity (FSAP GP), and FSAP GP/total FSAP (specific FSAP activity) were measured. Cardiac computed tomography (CT) determined the Agatston score, dividing the study population in three groups: (1) Agatston score = 0 U, (2) Agatston score = 1-99 U, or (3) Agatston score more than 99 U. A total of 134 women and 116 men were included. Total FSAP, FSAP GP, and specific FSAP activity were independently higher in women (97.4%, 81.1%, 0.84, respectively) compared with men (87.5%, 68.7%, 0.79, respectively) (P < 0.001). In women, total FSAP was significantly different between (3) Agatston score (111.5%) and (1) Agatston score (95.4%), respectively, (2) Agatston score (96.8%), (P < 0.05). Also, the specific activity of FSAP was significantly different between (3) Agatston score (0.77) and (1) Agatston score (0.85), respectively, (2) Agatston score (0.86) (P < 0.05). No difference in FSAP measures was observed in men. FSAP measures are higher in women compared with age-matched men. The extent of CAC in women is positively associated with total FSAP, but negatively associated with the specific activity of FSAP suggesting that FSAP may play a role in the evolution of CVD in women.

Fibrin metabolism is influenced by many factors. The velocity of fibrin formation, genetic polymorphisms, fibrinolytic features and the structure of the fibrin clot are determinants of fibrin turnover. Oral contraceptives (OCs) have significant impact on the haemostatic system, by increasing the concentration of coagulation factors, plasminogen and tissue plasminogen activator activity, and decreasing the concentration of haemostatic inhibitors. The present study addresses the influence of OCs on fibrin structure and fibrin metabolism. The study included 70 women treated with seven different OC-formulations. Blood was collected at baseline and after six months of OCs. The plasma concentration of fibrinogen, thrombin-antithrombin complex (TAT), plasminogen, plasmin-antiplasmin complex (PAP), D-Dimer and thrombin generation measures were determined. Fibrin structure measures and fibrin clot lysis not affected by the plasma concentration of plasminogen activators and inhibitors were determined. OCs increased the concentration of fibrinogen, TAT, plasminogen, PAP and D-dimer significantly and affected measures of thrombin generation (p<0.001). The maximal optical density of fibrin (p<0.001), the fibrin fibre density (p=0.03), fibrin fibre diameter (p=0.003), fibrin mass-length ratio (p<0.001) and lysis per hour (p<0.001) increased significantly upon OC-treatment. Lysis per hour was not correlated to the concentration of plasminogen. We conclude that the effect of OCs on the coagulation system is balanced by alterations in fibrin structure, facilitating clot lysis and contributing to the fibrinolytic susceptibility already present in women treated with OC. These alterations may counterbalance the OC-induced increased thrombin generation and reduced coagulation inhibitory potential, contributing to maintenance of the haemostatic balance in women receiving OCs.

Thrombolytic therapy involves thrombolytic agents administered to patients suffering from venous or arterial thrombosis. The therapy induces systemic effects interrelated with the thrombolytic agent used. Bleeding is a prominent complication of thrombolytic therapy. Exhaustion of coagulation factors, generation of excessive amounts of fibrin degradation products (FDPs), therapy-induced activation of coagulation, therapy-induced anticoagulation, and formation of new fibrin all illustrate the complexity of effects of the treatment and challenges the hemostatic balance in the patients. The therapy-induced effects can be modulated by parallel administration of anticoagulants. Risk assessment is mandatory prior to thrombolytic therapy. Anticoagulated and unconscious patients represent particular safety concerns, and should be fully evaluated. Several guidelines describe the choice of tests and their safety limits in relation to pretreatment evaluation of anticoagulated patients. Fibrinogen depletion and FDPs during treatment may be promising markers for the evaluation of bleeding risk posttreatment. Future risk assessment measures should focus on the dynamics of the hemostatic balance. Here, thromboelastography may be considered a tool addressing clot formation, fibrin structure, and fibrinolytic resistance in parallel. Suitable laboratory analysis performed shortly after treatment may help to recognize severe treatment-induced systemic effects that can be counteracted by rational treatment, thereby reducing bleeding risk., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Purpose: Bleeding volume in orthognathic surgery (OS) varies considerably, although OS comprises standardized procedures and the patient population consists of young healthy individuals. The aim of this prospective cohort study was to investigate the influence of preoperative sex-related differences in hemostatic parameters on intraoperative bleeding (IOB) volume in OS., Materials and Methods: Patients scheduled for routine OS in our department in Esbjerg, Denmark, were included as study patients in this short-term cohort study. The primary predictor variable was patient sex, and the primary outcome variable was IOB volume measured in milliliters. Secondary outcome variables included preoperative measures of hematologic variables, thromboelastography, fibrinogen concentration, D-dimer concentration, prothrombin fragment 1+2 (F1+2) concentration, and type of osteotomy. Data analyses included the χ(2) test, Mann-Whitney U test, Pearson product moment correlation analysis, and analysis of covariance for analyses of dichotomous variables, comparison between sex, correlations between IOB volume and secondary predictors, and adjustment for confounders, respectively., Results: Forty-one consecutive patients undergoing bimaxillary OS were included and subsequently grouped according to sex (26 men and 15 women). The main finding was that male patients bled twice as much as female patients on average (400 mL [interquartile range, 300 to 500 mL] vs 200 mL [interquartile range, 63 to 288 mL]; P = .001). Age and preoperative measures of thromboelastography, fibrinogen concentration, D-dimer concentration, and F1+2 concentration were significantly associated with sex (P = .001, P = .002, P = .007, and P = .014, respectively). The significant association between sex and IOB volume disappeared when adjusted for these confounders (P = .18)., Conclusions: Preoperative sex-related increases in measures of fibrin turnover predict IOB volume in bimaxillary OS, with women displaying a significantly lower IOB volume than men., (Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objectives: Disruption of the endothelial lining may be one of the events linking intraluminal thrombus and abdominal aortic aneurysm growth. In the present study, we examined whether von Willebrand factor activity in plasma, contact proteins of blood coagulation, and inflammatory biomarkers may be associated with intraluminal thrombus volume in search of a biochemical marker of endothelial damage and thrombus size., Design: Prospective study, correlating potential endothelial biomarkers and intraluminal thrombus volume acquired by computed tomography angiography., Materials and Methods: Plasma was consecutively obtained from 38 patients with asymptomatic infrarenal abdominal aortic aneurysm. von Willebrand factor activity, thrombin generation time, factor XII, and prekallikrein concentration were measured in plasma on automated and in-house platforms. In total, 8 patients were excluded due to ongoing anticoagulant therapy, renal impairment, or nonappearance, thus leaving 30 patients for further analysis. All patients had computed tomography angiography, and intraluminal volume was quantified off-line by OsiriX 6.5., Results: Median intraluminal thrombus volume was 42.7 mL. Spearman correlation analysis revealed a positive correlation between thrombus volume, von Willebrand factor activity (ρ = 0.56, P = .0013), and prekallikrein concentration in plasma (ρ = 0.54, P = .002)., Conclusion: von Willebrand factor activity and concentration of prekallikrein may both be of importance regarding the evolution of thrombus in abdominal aortic aneurysm and possible biomarkers for aneurysm growth., (© The Author(s) 2016.)

Human blood coagulation factor XII (FXII) is the one chain 80 kDa zymogen form of the active serine protease α-FXIIa, which consists of a heavy and light chain linked by a disulfide bond, the light chain being responsible for the proteolytical activity. FXII is the first component of the contact dependent pathway of coagulation, but its physiological role is still subject to debate. In the present study we utilized two monoclonal antibodies against the heavy chain of FXII to establish a sandwich enzyme linked immunosorbent assay (ELISA) for quantification of total FXII concentration in human plasma samples. A unique characteristic of this assay is its equal recognition of FXII and inhibitor bound FXII. This is important, as inhibitor complexes of α-FXIIa are formed in vivo as well as during blood sampling and handling. Validation of the assay demonstrated a high sensitivity, with a limit of detection and quantification of 1.2 ng/mL and 2.6 ng/mL respectively. The coefficients of variation for the repeatability and within-laboratory standard deviations were 2.6% and 5.2% respectively. The reference interval determined from healthy volunteers (n=240) was 10.6-43 mg/L., (Copyright © 2013 Elsevier B.V. All rights reserved.)

OBJECTIVE. To compare the cardiovascular disease (CVD) risk factor profile in subjects with screen-detected type 2 diabetes (SDM) and subjects with known type 2 diabetes (KDM). DESIGN. Population-based, cross-sectional survey. SETTING AND SUBJECTS. In a single, semi-rural general practice 2082 subjects were between 20 and 69 years. Of those, 1970 subjects were invited, and a total of 1374 (69.7%) subjects were examined by blood tests, anthropometric measures, and self-administered questionnaires. RESULTS. Before the survey 19 persons were known to have type 2 diabetes. The screening revealed another 31 individuals with type 2 diabetes, diagnosed according to the 1999 World Health Organization criteria. Age, levels of blood pressure, BMI, and dyslipidaemia, and markers of haemostasis and inflammation were comparable in the two groups. Median age in the KDM group was 58 vs. 57 years in the SDM group, p = 0.82, 79% were male vs. 61%, p = 0.23. In both groups 74% had blood pressure ≥ 130/85 mmHg, p = 1.00. In both groups 90% had BMI ≥ 25, p = 1.00, and about half in both groups had BMI ≥ 30, p = 0.56. In the KDM group 63% had dyslipidaemia (low HDL cholesterol or elevated triglycerides) vs. 80% in the SDM group, p = 0.32. Median levels of plasminogen-activator-inhibitor (PAI-1), tissue plasminogen activator (t-PA), as well as fibrinogen and C-reactive protein (CRP) were without statistically significant differences in the two groups, p > 0.1. In contrast, in markers of glycaemic regulation statistically significant differences were found between groups. Median HbA1 was 8.0 vs. 6.5, p < 0.001. Median fasting whole blood glucose level was 8.8 mmol/L vs. 6.3 mmol/L, p < 0.001, and glucose at two hours during OGTT was 16.9 mmol/L vs. 11.2 mmol/L, p < 0.001. Median fasting serum insulin level was 52 pmol/L vs. 80 pmol/L, p = 0.039 and at two hours 127 pmol/L vs. 479 pmol/L, p < 0.001. CONCLUSIONS. The CVD risk-factor profile of SDM patients was similar to the expected adverse profile of patients with KDM. This indicates an already increased risk of cardiovascular disease in diabetic patients before the diabetes becomes clinically manifest, supporting the need for early diagnosis.

We have studied the response of haemostatic reaction products in peripheral blood of patients with acute ischaemic heart disease receiving combined recombinant tissue type plasminogen activator/heparin therapy. We have found evidence that formation of excessive amounts of plasmin in vivo in relation to such therapy significantly enhances the degradation of fibrin, and of fibrinogen as well as the formation of thrombin. We conclude that excessive plasmin formation by thrombolytic therapy causes systemic effects including activation of coagulation.

This report reviews the major haemostatic deviations associated with the evolution of ischaemic heart disease (IHD) and also such deviations, which might be of importance for the evolution of the acute ischaemic heart syndrome. It is demonstrated that deviation in the t-PA/PAI-1 system indicate endothelial cell dysfunction in patients with IHD. Different factors which have the capability to induce such an endothelial cell dysfunction are proposed, i.e. hyperinsulinemia, mediators of chronic disease phase response, and thrombin. Finally, the intimate interrelation between coagulation and fibrinolysis in patients with IHD is discussed. The experimental and clinical studies reviewed provide good evidence that the endothelial cell response of t-PA and PAI-1 is coupled and that there is an intimate interrelation between generation of thrombin and production/release of t-PA and PAI-1 in IHD patients.

In a consecutive and unselected series of 100 male autopsies, the breasts were totally extirpated and histologically investigated. Gynecomasty was found in 55 cases, of which 48 were in healed and seven in still active, intermediate phase. All but two cases were bilateral. No clinical evidence of gynecomasty was established in any case. Thus, gynecomasty seems to be very common in men. In seven cases, severe intraductal epithelial hyperplasia was found, three of pagetoid and four of cribriform type. They belonged to the atypical hyperplastic--early intraductal carcinoma type. All cases were incidentally found and without known clinical relevance.

In a series of 80 consecutive mastectomies it was investigated histologically, by a horizontal sectioning technique, how often the nipple and/or areola were involved in breast cancer. Such involvement was found in 35 cases (43.8%). In the same series the value of the clinical findings as to involvement of the nipple and/or areola was assessed. Only 6 of the 35 cases had shown clinical changes that could give rise to a suspicion of spread to the nipple and/or areola.

In a retrospective histologic study of 1862 benign breast tissue specimens, 32 cases were found to have radial scar. The radial scar was multicentric in 44%, and found in breasts with fibrocystic disease and/or duct ectasia. During a follow-up period of 19.5 years (range, 15-24 years), one patient developed breast cancer compared with an expected rate of 0.94. Therefore, local excision of radial scar without further follow-up is sufficient.

In a consecutive and unselected series of 83 patients operated upon for gynecomasty, the histological and related clinical aspects were studied. It was convincingly demonstrated that gynecomasty begins in an active proliferating phase and ends in a fibrous inactive phase. Contrary to previous authors we found it justified that the formation of lobules, indistinguishable from what is seen in the reproduceable age in the female breast, is not necessarily related to the administration of exogenic hormones. In five (6.5%) cases, typical multicentric foci of intraductal epithelial hyperplasia were demonstrated--of the atypical hyperplastic or early intraductal carcinoma type. It was concluded that the clinical significance of such morphological changes must not be overestimated.