Contact activated kallikrein generation is reduced six months after gastric bypass.

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 (rS): -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 (rS = -0.29, p = 0.025), but also with triglycerides (rS = 0.34, p = 0.007) and cholesterol (rS = 0.28, p = 0.029), and independently associated with changes in C1-inh (ß = -0.40) and triglycerides (ß = 0.39). Changes in C1-inh associated with reductions in body weight (ß = -0.39) and HbA1c (ß = 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.

Orthognathic Surgery-Induced Fibrinolytic Shutdown Is Amplified by Tranexamic Acid.

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.

Fibrin lysability is associated with central obesity and inflammation in women with polycystic ovary syndrome.

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 (r2  = .46, P ≤ .001), but only with CFM in controls (r2  = .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.

Carotid plaque composition by CT angiography in asymptomatic subjects: a head-to-head comparison to ultrasound.

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.

Sex difference in fibrin clot lysability: Association with coronary plaque composition.

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 mm3 had lower fibrin clot lysability compared to women with total plaque volume = 0 mm3, 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 mm3, 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.

Sex difference in clot lysability and association to coronary artery calcification.

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.

High burden of coronary atherosclerosis in patients with a new diagnosis of type 2 diabetes.

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 mm3; 0-50.5 mm3 vs 0; 0-34.3 mm3, 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.

Fast form alpha-2-macroglobulin - A marker for protease activation in plasma exposed to artificial surfaces.

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 α2-macroglobulin (F-α2M), 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-α2M specific monoclonal antibody was generated and applied in an ELISA setup. Using the F-α2M 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-α2M is a sensitive marker for activation of both calcium dependent and in-dependent proteases. A significant difference between F-α2M 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-α2M concentration was in both cases found in plasma incubated with glass. CONCLUSIONS: Our findings demonstrate that F-α2M is a sensitive marker for detection of protease activation in plasma by artificial surfaces. Potentially, levels of F-α2M could be a global marker of the blood compatibility of biomaterials.

Factor VII-activating protease: sex-related association with coronary artery calcification.

: 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 clot structure - pro-fibrinolytic effect of oral contraceptives in apparently healthy 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.

Assessing Safety of Thrombolytic Therapy.

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.

von Willebrand Factor and Prekallikrein in Plasma Are Associated With Thrombus Volume in Abdominal Aortic Aneurysms.

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.

Similar cardiovascular risk factor profile in screen-detected and known type 2 diabetic subjects.

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.