Prothrombotic Fibrin Clot Phenotype Research Articles

Reduced Plasma Selenoprotein P Is Associated With Type I Antithrombin Deficiency and a Prothrombotic State.

A positive association between antithrombin activity and selenium level was reported. Selenoprotein P, the most important selenium carrier, was identified within human plasma fibrin clots. To investigate the relationship between selenoprotein P and antithrombin and its role in modulation of fibrin clot properties in antithrombin-deficient patients. Proteomic analysis of plasma fibrin clots was performed with mass spectrometry. In 108 patients with genetically confirmed type I (57%) or type II (43%) antithrombin deficiency and in healthy controls (n = 50), we assessed plasma selenoprotein P levels and thiobarbituric acid-reactive substances by enzyme-linked immunosorbent assay, along with fibrin clot permeability, clot lysis time, and thrombin generation. Clot-bound antithrombin concentration was 0.46 ± 0.32 mg/g protein, while selenoprotein P level was 30-fold lower (0.015 ± 0.012 mg/g). Type I compared to type II antithrombin-deficient patients had higher clot-bound antithrombin and selenoprotein P levels (both P < .001), associated together (ρ = 0.93, P < .001). Individuals with type I compared to type II antithrombin deficiency or controls had about 40% lower plasma selenoprotein P levels (P < .001). In antithrombin-deficient patients, plasma selenoprotein P was associated with antithrombin antigen (ρ = 0.35, P < .001) and thiobarbituric acid-reactive substances (ρ = 0.42, P < .001). Plasma selenoprotein P correlated also with endogenous thrombin potential (r = -0.33, P < .001), fibrin clot permeability (r = 0.43, P < .001), and clot lysis time (r = -0.40, P < .001) in antithrombin-deficient patients but not in controls. Patients with type I antithrombin deficiency had higher clot-bound selenoprotein P and reduced plasma selenoprotein P levels. Plasma selenoprotein P was associated with prothrombotic fibrin clot phenotype and enhanced thrombin generation.

Elevated plasma protein carbonylation increases the risk of ischemic cerebrovascular events in patients with atrial fibrillation: association with a prothrombotic state.

Plasma protein carbonylation that reflects oxidative stress has been demonstrated to be associated with the prothrombotic fibrin clot phenotype. However, the role of protein carbonyls (PC) in predicting ischemic stroke in atrial fibrillation (AF) is largely unknown. This study aimed to investigate whether PC increase the risk of stroke in anticoagulated AF patients during follow-up. In 243 AF patients on anticoagulation (median age 69years; median CHA2DS2-VASc of 4), we measured plasma PC using the assay by Becatti, along with plasma clot permeability (Ks), clot lysis time (CLT), thrombin generation, and fibrinolytic proteins, including plasminogen activator inhibitor type 1 (PAI-1) and thrombin activatable fibrinolysis inhibitor (TAFI). Ischemic stroke, major bleeding, and mortality were recorded during a median follow-up of 53months. Plasma PC levels (median, 3.16 [2.54-3.99] nM/mg protein) at baseline showed positive associations with age (P < 0.001), CHA2DS2-VASc (P = 0.003), and N-terminal B-type natriuretic peptide (P = 0.001), but not with type of AF or comorbidities except for heart failure (P = 0.007). PC levels were correlated with CLT (r = 0.342, P < 0.001), endogenous thrombin potential (r = 0.217, P = 0.001) and weakly with Ks (r = -0.145, P = 0.024), but not with fibrinogen, PAI-1, or TAFI levels. Stroke was recorded in 20 patients (1.9%/year), who had at baseline 36% higher PC levels (P < 0.001). Elevated PC (P = 0.003) at baseline were independently associated with stroke risk. Our findings suggest that in patients with AF enhanced protein carbonylation is associated with increased "residual" risk of stroke despite anticoagulation, which is at least in part due to unfavorably altered fibrin clot phenotype.

Prothrombotic plasma fibrin clot phenotype is associated with spontaneous echo contrast in atrial fibrillation: The role of protein carbonylation

IntroductionSpontaneous echo contrast (SEC) and left atrial appendage thrombus (LAAT) increase the risk of stroke and its severity in patients with atrial fibrillation (AF). Formation of denser fibrin networks and impaired fibrinolysis are associated with stroke risk in AF. This study investigated whether the prothrombotic fibrin clot phenotype characterizes patients with SEC/LAAT. MethodsWe studied 139 anticoagulated patients with AF (median age, 70 years), who underwent transesophageal echocardiography (TEE). SEC and LAAT were recorded. We assessed plasma fibrin clot properties, i.e. permeability (Ks) and clot lysis time (CLT), von Willebrand Factor (vWF) antigen, endogenous thrombin potential (ETP), proteins involved in thrombosis and fibrinolysis, as well as plasma carbonylated protein content (PC). ResultsSEC/LAAT was identified in 36 subjects (25.9 %) and was associated with heart failure (HF), AF duration, higher CHA2DS2VASc score, N-terminal prohormone of brain natriuretic peptide, and growth differentiation factor 15. Patients with SEC/LAAT had lower Ks (−15 %) and prolonged CLT (+19 %), along with higher fibrinogen (+24 %), ETP (+3 %), and plasminogen activator inhibitor-1 antigen (+16 %) compared with the remainder. Thrombin-activatable fibrinolysis inhibitor antigen, plasminogen, α2 − antiplasmin, and tissue plasminogen activator antigen were similar between the two groups. PC content was 50 % higher in SEC/LAAT and correlated with Ks (r = −0.47, p < 0.001) and CLT (r = 0.40, p < 0.001). On multivariate analysis, Ks, CLT, and PC levels, along with HF, remained independently associated with SEC/LAAT. ConclusionsWe demonstrated a formation of denser and poorly lysable fibrin networks in AF patients with SEC/LAAT despite anticoagulation. We suggest that this phenomenon is in part related to enhanced oxidative stress.

Elevated plasma factor XI is predicts cardiovascular complications in patients with type 2 diabetes mellitus

Abstract Background Atherothrombotic complications are common in patients with type 2 diabetes mellitus (T2DM), reflecting a chronic prothrombotic state. Circulating factor XI (FXI) has been associated with a prothrombotic fibrin clot phenotype and predicted myocardial infarction, stroke and cardiovascular (CV) death in a number of diseases, including CAD. Its role in T2DM is largely unknown. Purpose The purpose of this study was to assess plasma FXI as a predictor of atherothrombotic events in T2DM patients. We also aimed to establish the determinants of elevated plasma FXI in this group of patients. Methods In a cohort of 156 patients aged 43–83 years, 56% male, with T2DM of a median duration time of five years, 64.7% with diagnosed CAD, we measured FXI along with a number of fibrin clot parameters, including turbidity, permeation, compaction, lysability, maximum concentration of D-dimer (D-D max), and rate of D-dimer release during tissue plasminogen activator-induced clot lysis. Patients were followed for a median time of 72 (68-74) months for a composite endpoint of nonfatal myocardial infarction (MI), nonfatal stroke, and cardiovascular (CV) death. Results Follow-up was complete for 133 (85.3%) patients. There were 21 (16%) cases of the composite endpoint, including one nonfatal MI, four nonfatal strokes and 16 cases of CV death. Patients with and without the composite endpoint shared a similar demographic and clinical profile with the exception of age and white blood cell count – patients with the endpoint were older (69.4 [8.4] vs. 65.4 [7.8] years, p=0.03) and had a higher leukocyte count (7.8 [1.9] vs. 7.0 [1.3], p=0.02) as compared with the remainder. FXI was elevated above the upper limit of 120% in 25 (18.8%) patients, including 16 (61.9%) with the composite endpoint vs. 12 (10.7%) without the composite endpoint, p&amp;lt;0.001. Individuals with the composite endpoint had higher baseline FXI concentrations as compared with the remainder (120.1±16.8 vs. 104.9±10.7%. p &amp;lt; 0.001), along with higher D-D max (4.1 [3.8-4.3] vs. 3.8 [3.6-4.1] mg/l, p = 0.006) and slightly longer lysis time (t50% 10.1 [9.8-10.9] vs. 9.8 [8.9-10.4] min, p = 0.03). On multivariable analysis, co-existing CAD, LDL cholesterol, and thrombin activatable fibrinolysis inhibitor activity were independent predictors of elevated FXI in T2DM patients. Conclusion Elevated plasma FXI in T2DM patients is associated with CAD, LDL cholesterol and TAFI, and predicts myocardial infarction, stroke, and CV death in long term follow-up. Our finding may have implications for risk stratification and suggests a role for FXI inhibitors in T2DM patients with a high risk of atherothrombotic complications.

Protein Carbonylation Contributes to Prothrombotic Fibrin Clot Phenotype in Acute Ischemic Stroke: Clinical Associations.

Acute ischemic stroke (AIS) is associated with enhanced oxidative stress and unfavorably altered fibrin clot properties. We investigated determinants of plasma protein carbonylation (PC) in AIS, its impact on the prothrombotic state, and prognostic value during follow-up. We included 98 consecutive AIS patients aged 74±12 years (male:female ratio, 50:48 [51%:49%]) at the Neurology Center in Warsaw, Poland, between January and December 2014. As many as 74 (75.5%) patients underwent thrombolysis, and 24 were unsuitable for thrombolysis. We determined plasma PC, along with thrombin generation, fibrin clot permeability, and clot lysis time on admission, at 24 hours, and 3 months. Stroke severity was assessed using the National Institutes of Health Stroke Scale and stroke outcome with the modified Rankin Scale. Hemorrhagic transformation was assessed on the computed tomography scan within 48 hours from the symptom onset, while stroke-related mortality was evaluated at 3 months. On admission, PC levels (median, 4.61 [3.81-5.70] nM/mg protein) were associated with the time since symptom onset (r=0.41; P<0.0001) and with the National Institutes of Health Stroke Scale score (P=0.36; P=0.0003). Higher PC levels on admission correlated with denser fibrin clot formation and prolonged clot lysis time but not with thrombin generation. In thrombolysed patients, lower PC levels were observed after 24 hours (-34%) and at 3 months (-23%; both P<0.001). PC levels at baseline and after 24 hours predicted the modified Rankin Scale score >2 at 3 months (OR, 1.90 [95% CI, 1.21-3.00]; OR, 2.19 [95% CI, 1.39-3.44], respectively). Higher PC at baseline predicted hemorrhagic transformation of stroke (OR, 1.95 [95% CI, 1.02-3.74]) and stroke-related mortality (OR, 2.02 [95% CI, 1.08-3.79]), while higher PC at 24 hours predicted solely stroke-related mortality (OR, 2.11 [95% CI, 1.28-3.46]). Elevated plasma PC levels in patients with AIS, related to prothrombotic fibrin clot properties, are associated with stroke severity. Thrombolysis reduces the extent of PC. The current study suggests a prognostic value of PC in AIS.

PB0444 Residual Pulmonary Vascular Obstruction is Associated with Prothrombotic Fibrin Clot Phenotype in Patients Following Pulmonary Embolism

PB0444 Residual Pulmonary Vascular Obstruction is Associated with Prothrombotic Fibrin Clot Phenotype in Patients Following Pulmonary Embolism

PB0036 Plasma Protein Carbonyl Levels Contribute to Prothrombotic Fibrin Clot Phenotype in Acute Ischemic Stroke Patients: Associations with Clinical Outcomes

PB0036 Plasma Protein Carbonyl Levels Contribute to Prothrombotic Fibrin Clot Phenotype in Acute Ischemic Stroke Patients: Associations with Clinical Outcomes

Elevated factor XIa as a modulator of plasma fibrin clot properties in coronary artery disease.

Patients with coronary artery disease (CAD) display a prothrombotic fibrin clot phenotype, involving low permeability and resistance to lysis. The determinants of this phenotype remain elusive. Circulating tissue factor (TF) and activated factor XI (FXIa) are linked to arterial thromboembolism. We investigated whether detectable active TF and FXIa influence fibrin clot properties in CAD. In 118 CAD patients (median age 65 years, 78% men), we assessed Ks, an indicator of clot permeability, and clot lysis time (CLT) in plasma-based assays, along with the presence of active TF and FXIa. We also analysed proteins involved in clotting and thrombolysis, including fibrinogen, plasminogen activator inhibitor-1 (PAI-1) and thrombin activatable thrombolysis inhibitor (TAFI). During a median 106 month (interquartile range 95-119) follow-up, myocardial infarction (MI), stroke, systemic thromboembolism (SE) and cardiovascular (CV) death were recorded. Circulating TF and FXIa, detected in 20.3% and 39.8% of patients, respectively, were associated with low Ks and prolonged CLT. Solely FXIa remained an independent predictor of low Ks and high CLT on multivariable analysis. Additionally, fibrinogen and PAI-1 were associated with low Ks, while PAI-1 and TAFI-with prolonged CLT. During follow-up low Ks and prolonged CLT increased the risk of MI and the latter also a composite endpoint of MI, stroke/SE or CV death. To our knowledge, this study is the first to show that circulating FXIa is associated with prothrombotic fibrin clot properties in CAD, suggesting additional mechanisms through which FXIa inhibitors could act as novel antithrombotic agents in CAD.

Effect of high-dose statin therapy on coagulation factors: Lowering of factor XI as a modifier of fibrin clot properties in coronary artery disease

BackgroundMultiple pleiotropic effects of statins include antithrombotic properties with formation of looser fibrin networks more susceptible to lysis. Recently, rosuvastatin 20 mg/d has been reported to decrease coagulation factors (F) VII, FVIII and FXI in venous thrombosis patients. ObjectivesWe investigated how high-dose statin therapy recommended in coronary artery disease (CAD) alters plasma levels of coagulation factors and if such changes might affect fibrin clot properties. MethodsWe studied 130 advanced CAD patients, who initially did not achieve the target low-density lipoprotein cholesterol (LDL-C). Before high-dose statin therapy (rosuvastatin 40 mg/d or atorvastatin 80 mg/d) and 6–12 months after its initiation, FII, FV, FVII, FVIII, FIX, FX, FXI and fibrinogen were assessed. We evaluated the impact of statin-induced alterations to the factors on plasma fibrin clot permeability (Ks) reflecting a fibrin pore size, and clot lysis time (CLT) reflecting fibrinolytic potential. ResultsAt baseline LDL-C (median 3.2, interquartile range 2.7–3.7 mmol/L) was independently associated solely with FXI (β = 0.58, P < 0.001). Median LDL-C reduction by 25% (P < 0.001) on high-dose statin treatment was accompanied by lowering of FVII, FVIII, and FXI (for all P < 0.001). On high-dose statin treatment, Ks (R = 0.65, P < 0.001) inversely associated with CRP (β = −0.41, P < 0.001), LDL-C (β = −0.26, P = 0.001), and FXI (β = −0.18, P = 0.016). In turn, CLT (R = 0.45, P < 0.001) was positively associated with LDL-C (β = 0.19, P = 0.043) and FXI (β = 0.17, P = 0.049). ConclusionsHigh-dose statin therapy in CAD patients decreases FVII, FVIII, and FXI. The statin-induced reduction in FXI may contribute to less prothrombotic fibrin clot phenotype, indicating additional antithrombotic effect of high-dose statins.

Apolipoproteins and lipoprotein(a) as factors modulating fibrin clot properties in patients with severe aortic stenosis

Background and aimsLarge amounts of clot-bound lipoproteins were reported in proteomic analysis of plasma clot but their impact on fibrin clot properties is unknown. We investigated a contribution of lipid profile and apolipoproteins (apo) to the prothrombotic plasma fibrin clot phenotype in patients with aortic stenosis (AS). MethodsIn 138 patients with isolated severe AS, we determined serum apoA-I, A-II, B, C-II, C-III, E, oxidized low-density lipoprotein (OxLDL) and lipoprotein(a) concentrations. Plasma fibrin clot permeability (Ks), maximal absorbance (MaxAbsCLT2018 and MaxAbsLys50), and fibrinolytic capacity were studied using 3 plasma-based lysis assays (CLT2018, CLT, and Lys50), and compared with well-matched patients without AS (control group). ResultsAfter adjustment for confounding factors, including statin use, only low-density lipoprotein cholesterol (LDL-C) and apoB levels were inversely associated with Ks. Triglycerides, apoC-II, and C-III were associated with MaxAbsCLT2018 and MaxAbsLys50, explaining 56–64% of their variability. CLT2018 and CLT showed associations with total cholesterol, LDL-C, triglycerides, and OxLDL as well as with apoB, C-II, C-III, and E. ApoA-I, C-II, and C-III but not serum lipids were associated with Lys50. Only CLT2018 was associated with lipoprotein(a). ApoC-III, B, A-I, and E along with estimated glomerular filtration rate and OxLDL predicted hypofibrinolysis in multiple regression analysis. AS patients had higher lipoprotein(a) (+34.9%) and apoA-I (+25.9%) levels and less compact fibrin clots (−13.3% lower MaxAbsCLT2018, -53.2% lower MaxAbsLys50, and +28.3% higher Ks) displaying higher susceptibility to lysis (−17.9% lower Lys50) in comparison with control group. ConclusionsApolipoproteins and OxLDL contribute to prothrombotic fibrin clot phenotype in severe AS. Moreover, apolipoproteins better than serum lipids predicted hypofibrinolysis, which provides additional argument for a role of elevated lipoproteins in the prothrombotic state.

Fibrinogen β chain and FXIII polymorphisms affect fibrin clot properties in acute pulmonary embolism.

Prothrombotic fibrin clot properties, including increased clot density, are in part genetically determined. We investigated whether fibrinogen alpha-chain gene (FGA) c.991A>G (rs6050), fibrinogen beta chain gene (FGB) -455G>A (rs1800790) and factor XIII gene (F13) c.103G>T (rs5985) polymorphisms affect plasma fibrin clot properties in patients with acute pulmonary embolism (PE). As many as 126 normotensive patients with PE, free of cancer, were genotyped by TaqMan assay. Fibrin clot permeability (Ks ), clot lysis time (CLT) and endogenous thrombin potential (ETP) were assessed on admission. The minor allele frequencies were as follows: FGA rs6050 (n=62, 0.31), FGB rs1800790 (n=40, 0.17) and F13 rs5985 (n=49, 0.23). There were no differences related to any of the polymorphisms with regard to demographic, clinical and laboratory data, except for fibrinogen concentration, which was higher in carriers of F13 rs5985 polymorphism (p=.024), and PE combined with deep-vein thrombosis, which was less prevalent in FGB rs1800790 polymorphism carriers (p=.004). Carriers of FGB rs1800790 A allele and F13 rs5985T allele had lower Ks , prolonged CLT and higher ETP compared with major homozygotes (all p<.05). After adjustment for fibrinogen, all differences remained significant (all p<.01). There were no associations between the FGA rs6050 polymorphism and Ks , CLT or ETP. Our study showed that FGB rs1800790 and F13 rs5985 polymorphisms contribute to the prothrombotic fibrin clot phenotype and these effects are strong enough to be observed in the acute phase of PE.

Fibrin Clot Properties in Atherosclerotic Vascular Disease: From Pathophysiology to Clinical Outcomes.

Fibrin is a major component of thrombi formed on the surface of atherosclerotic plaques. Fibrin accumulation as a consequence of local blood coagulation activation takes place inside atherosclerotic lesions and contributes to their growth. The imbalance between thrombin-mediated fibrin formation and fibrin degradation might enhance atherosclerosis in relation to inflammatory states reflected by increased fibrinogen concentrations, the key determinant of fibrin characteristics. There are large interindividual differences in fibrin clot structure and function measured in plasma-based assays and in purified fibrinogen-based systems. Several observational studies have demonstrated that subjects who tend to generate denser fibrin networks displaying impaired clot lysis are at an increased risk of developing advanced atherosclerosis and arterial thromboembolic events. Moreover, the majority of cardiovascular risk factors are also associated with unfavorably altered fibrin clot properties, with their improvement following effective therapy, in particular with aspirin, statins, and anticoagulant agents. The prothrombotic fibrin clot phenotype has been reported to have a predictive value in terms of myocardial infarction, ischemic stroke, and acute limb ischemia. This review article summarizes available data on the association of fibrin clot characteristics with atherosclerotic vascular disease and its potential practical implications.

Fibrin clot properties among women with endometriosis and the impact of ovarian stimulation

Research questionIs there a difference in fibrin clot phenotype in women with endometriosis before and after ovarian stimulation? DesignProspective study including 73 infertile women in two age-matched groups: (i) with confirmed endometriosis (n = 29); (ii) without endometriosis (n = 44). Assessments of plasma fibrin clot permeability (Ks), efficiency of fibrinolysis using clot lysis time (CLT), along with thrombin generation (prothrombin fragments 1+2 [F1+2] and endogenous thrombin potential [ETP]) and fibrinolysis inhibitors were performed together with clinical pregnancy rate. ResultsEndometriosis was associated with increased thrombin generation, reflected by both higher F1+2 (+96.1%, P = 0.005) and ETP (+14.2%, P = 0.014) along with unfavourably altered fibrin clot properties represented by lower Ks (–31%, P < 0.001) and prolonged CLT (+13.5%, P = 0.02), compared with the non-endometriosis group. Moreover, women with endometriosis had higher plasminogen activator inhibitor-1 (PAI-1; +272%, P = 0.004) concentrations and alpha-2-antiplasmin activity (+39.9%, P < 0.001) in contrast to the other group. Ovarian stimulation led to reduction in F1+2 (–48.1%, P < 0.001), improvement of fibrin clot phenotype reflected by higher Ks (+25.9%, P < 0.001) and shortened CLT (–11.9%, P < 0.001), along with lower PAI-1 (–54%, P = 0.016) compared with the baseline in women with endometriosis. ConclusionsEndometriosis is associated with the prothrombotic fibrin clot phenotype and increased thrombin generation. Ovarian stimulation favourably alters fibrin clot properties and leads to comparable pregnancy outcomes to those in women without endometriosis.

A prothrombotic state and denser clot formation in patients following acute limb ischemia of unknown cause

IntroductionFibrin clot structure differs between healthy individuals and those following thromboembolic events. Dense and poorly lysable fibrin clots have also been reported in peripheral artery disease. We studied fibrin clot properties and its determinants in individuals with a history of acute lower limb ischemia (ALI) of unknown cause. Materials and methodsIn this case-control study, we enrolled 43 patients who experienced ALI of unknown cause, and two age-and sex-matched reference groups: (1) patients with cryptogenic non-lacunar stroke (n = 43) and (2) individuals without any history of thromboembolism (n = 43, control group). Plasma fibrin clot properties, along with thrombin generation and fibrinolysis markers were assessed following ≥3 months of anticoagulation. ResultsCompared with the control group, the ALI group exhibited more compact plasma fibrin clots (13.4% lower permeability [Ks], p = .001), decreased formed clot lysis (12.5% lower D-Drate, p = .001) and unaltered clot lysis potential, along with enhanced thrombin generation potential (49% higher peak thrombin concentration, p < .0001). There were no differences in these variables between ALI and stroke patients. Patients with ALI had slightly higher α2-antiplasmin and lower plasminogen activator inhibitor 1 levels compared with the stroke and control groups (all p < .01). ConclusionsPatients who experienced ALI of unknown cause display a prothrombotic fibrin clot phenotype, including increased clot density and hypofibrinolysis associated with higher thrombin generation, which might suggest potential benefits from prolonged anticoagulation in this disease.

Prothrombotic clot properties can predict venous ulcers in patients following deep vein thrombosis: a cohort study

Venous ulcers are the most severe manifestation of post-thrombotic syndrome (PTS). We have previously demonstrated that formation of compact fibrin clots resistant to lysis is observed in patients following deep-vein thrombosis (DVT) who developed PTS. The current study investigated whether unfavourable fibrin clot properties can predict post-thrombotic venous ulcers. In a cohort study on 186 consecutive patients following DVT, we determined plasma fibrin clot characteristics, including clot permeability and lysability, inflammatory markers, thrombin generation, fibrinolysis proteins at 3 months since the index event. Occurrence of PTS and venous ulcers was recorded during follow-up (median, 53; range 24 to 76 months). Fifty-seven DVT patients (30.6%) developed PTS, including 12 subjects (6.45%) with a venous ulcer (4 individuals with recurrent ulcers). Patients who developed ulcers compared with the remainder had at enrolment 13.0% lower clot permeability (Ks), 17.4% longer clot lysis time (CLT), 13.1% longer lag phase of clot formation, and 5.0% higher maximum absorbance, with no difference in fibrinogen, C-reactive protein, and thrombin generation. The baseline prothrombotic fibrin clot phenotype (Ks ≤ 6.5 × 10−9 cm2 and CLT > 100 min) was associated with a higher risk of ulcers [hazard ratio (HR), 5.37; 95% confidence interval (CI), 1.3–21.5]. A multivariate model adjusted for age, sex, and fibrinogen showed that independent predictors of the ulcer occurrence were body mass index (HR 1.53; 95% CI 1.30–1.86), CLT (HR 1.43; 95% CI 1.04–2.05), and α2-antiplasmin (HR 0.95; 95% CI 0.90–0.99). This study suggests that formation of denser fibrin clots with impaired fibrinolysis predisposes to post-thrombotic venous ulcers.

Differences in plasma fibrin clot composition in patients with thrombotic antiphospholipid syndrome compared with venous thromboembolism

The prothrombotic fibrin clot phenotype has been reported in patients with thrombotic antiphospholipid syndrome (APS) and venous thromboembolism (VTE). Protein composition of plasma fibrin clots in APS has not been studied. We evaluated 23 patients with thrombotic APS, 19 with VTE alone, and 20 well-matched controls. A proteomic analysis of fibrin clots generated from citrated plasma was based on liquid chromatography-mass spectrometry. Plasma levels of thrombospondin-1 (TSP1), apolipoprotein(a), A-I, and B-100, complement components (C)3a, C5b-C9, histidine-rich glycoprotein (HRG), and prothrombin were evaluated using immunoenzymatic tests. In plasma fibrin clots of APS patients, compared with VTE subjects and controls, we identified decreased amounts of (pro)thrombin, antithrombin-III, apolipoprotein A-I, and HRG with no differences in plasma levels of antithrombin, prothrombin, along with lower plasma HRG and apolipoprotein A-I. In APS patients, plasma HRG positively correlated with amounts of clot-bound HRG, while apolipoprotein A-I was inversely associated with clot-bound levels of this protein. The most predominant proteins within the clots of APS patients were bone marrow proteoglycan, C5-C9, immunoglobulins, apolipoprotein B-100, platelet-derived proteins, and TSP1. Our study is the first to demonstrate differences in the protein composition of fibrin clots generated from plasma of thrombotic APS patients versus those with VTE alone.

Altered Plasma Clot Properties and Trauma-Related Venous Thromboembolism despite Thromboprophylaxis.

Prothrombotic clot phenotype may characterize patients developing deep vein thrombosis (DVT) despite pharmacological thromboprophylaxis. We studied the role of fibrin clot properties and its potential determinants in individuals who experienced DVT after lower limb injury. In a case-control study, we assessed 50 patients who developed DVT despite prophylactic use of low-molecular-weight heparins (the failed thromboprophylaxis group) after a lower limb injury, and three age- and sex-matched control groups, 50 patients each: (1) patients with trauma-related DVT without prior thromboprophylaxis; (2) individuals with unprovoked DVT; (3) patients without history of DVT (the no-DVT controls). Fibrin clot properties, along with thrombin concentration and α2-antiplasmin, were assessed following 3 months of anticoagulation in all DVT patients. Compared with the no-DVT controls, the failed thromboprophylaxis group exhibited denser fibrin networks (12.8% lower clot permeability [Ks], p = 0.0008) and impaired fibrinolysis (46.2% longer clot lysis time [CLT], p = 0.0001 and 8% lower rate of D-dimer release from clots, p = 0.0008). In the unprovoked DVT, similar Ks and 14.9% shorter CLT (p = 0.02) were reported compared with the failed thromboprophylaxis group. The failed thromboprophylaxis patients had higher odds of having elevated peak thrombin generation (>241.5 nM, 90th percentile in the no-DVT controls; odds ratio [OR]: 3.62; 95% confidence interval [CI], 1.86-7.06; p = 0.002), and higher odds of having elevated α2-antiplasmin (>115.05%; OR: 3.38; 95% CI, 1.64-6.98; p = 0.001). Patients who experienced DVT despite thromboprophylaxis following lower limb trauma display a strongly prothrombotic fibrin clot phenotype, including increased clot density and hypofibrinolysis associated with higher plasma α2-antiplasmin.

Altered plasma clot properties increase the risk of recurrent deep vein thrombosis: a cohort study

AbstractIt has been demonstrated that fibrin clots generated from plasma samples obtained from patients with prior thromboembolic events are denser and less susceptible to lysis. Such a prothrombotic fibrin clot phenotype has been suggested as a new risk factor for venous thromboembolism, but its prognostic value is unclear. To assess whether abnormal clot properties can predict recurrent deep vein thrombosis (DVT), we studied 320 consecutive patients aged 18 to 70 years following the first-ever DVT. Plasma clot properties were evaluated after 3 months of anticoagulant treatment since the index event. A mean duration of anticoagulation was 10 months (range, 4-20). Recurrent DVT was observed in 77 patients (25%; 6.6%/year) during a median follow-up of 44 months. Recurrences of DVT were associated with faster formation (−9% lag phase) of denser fibrin networks (−12% fibrin clot permeability [Ks]) and 4% higher maximum absorbance of plasma clots that displayed impaired fibrinolytic degradation (+25% prolonged clot lysis time [CLT]) and a 5% slower rate of increase in D-dimer levels during clot degradation (D-Drate; all P < .05). Proximal DVT alone, higher C-reactive protein, D-dimer, peak thrombin, lower Ks, shorter lag phase, decreased D-Drate, and prolonged CLT were independent predictors of recurrences (all P < .05). Individuals characterized by low Ks (≤7.3 × 10−9 cm2) and prolonged CLT (>96 min) were at the highest risk of recurrent DVT (odds ratio, 15.8; 95% confidence interval, 7.5-33.5). Kaplan-Meier curves showed that reduced Ks and prolonged CLT predicted recurrent DVT. We demonstrate that unfavorably altered clot properties may predict recurrent DVT after anticoagulation withdrawal.

Plasma fibrin clot structure and thromboembolism: clinical implications.

Fibrin formed as a result of fibrinogen polymerization is the main protein component of a clot in a test tube and intravascular thrombi in vivo. Fibrin clot structure characterized by fiber diameter and pore size differs between healthy persons and those with thromboembolic diseases, in part due to the quality and quantity of fibrinogen and the magnitude of thrombin generation. A key measure of plasma clot structure is its permeability, reflected by the Darcy constant (Ks). Reduced Ks is a typical feature of the prothrombotic fibrin clot phenotype, which is associated with faster formation of denser fibrin mesh, relatively resistant to lysis. Low Ks has been reported in patients with prior or acute myocardial infarction (MI), stroke, or venous thromboembolism (encompassing deep vein thrombosis [DVT] and pulmonary embolism [PE]), as well as in those with prothrombotic conditions (eg, in several thrombophilic states) and in the presence of cardiovascular risk factors (eg, obesity). Antithrombotic and anticoagulant agents, along with statins, have been shown to increase Ks. Growing evidence indicates associations between the properties of plasma fibrin clots and morphology of intravascular thrombi in patients with MI. Recently, reduced Ks has been shown to predict recurrent thromboembolic episodes in patients with a history of stroke, PE, DVT, and their serious complications, including postthrombotic syndrome and thromboembolic pulmonary hypertension. We discuss the current evidence for the significance of clot density measured in vitro as a prognostic marker in a number of clinical conditions associated with elevated thromboembolic risk.

Prothrombotic Fibrin Clot Phenotype in Patients with Deep Vein Thrombosis and Pulmonary Embolism: A New Risk Factor for Recurrence.

Prothrombotic fibrin clot phenotype, involving faster formation of dense meshwork composed of thinner and highly branched fibers that are relatively resistant to plasmin-induced lysis, has been reported in patients with not only myocardial infarction or stroke, but also venous thromboembolism (VTE), encompassing deep vein thrombosis (DVT), and/or pulmonary embolism (PE). Prothrombotic fibrin clot phenotype, in particular prolonged clot lysis time, is considered a novel risk factor for VTE as well as venous thrombosis at unusual location, for example, cerebral sinus venous thrombosis, retinal vein obstruction, and Budd-Chiari syndrome. Growing evidence from observational studies indicates that abnormal fibrin clot properties can predict recurrent DVT and PE and they are involved in serious complications of VTE, for example, thromboembolic pulmonary hypertension and postthrombotic syndrome. The purpose of this article is to review our current understanding of the role of fibrin clot structure and function in venous thrombosis with emphasis on clinical issues ranging from prognosis to therapy.