Fibrin clot permeability (Ks) in patients on left ventricular assist device.

Patients on left ventricular assist devices (LVAD) are prone to excessive hemostasis disturbances due to permanent contact of artificial pump surfaces with blood components. We aimed to investigate if fibrin clot permeability is altered in patients on long-term continuous-flow LVAD therapy and if the clot permeability is associated with clinical characteristics and adverse events. We investigated 85 end-stage heart failure patients (90.6% men, age 48.6-63.8 years) scheduled for continuous flow long-term LVAD support according to current clinical indications. The patients were assessed periodically: prior to LVAD implantation (T1), 3-6 months (T2) after LVAD implantation, 6-12 months after (T3) and then every 6 months. We tested the first three blood samples (T1-T3) and the last available blood sample (T4), but no longer than 5 years after LVAD implantation. We assessed hemostasis parameters (Activated Partial Thromboplastin Time (APTT) Prothrombin Time, Activated Partial Thromboplastin Time, Fibrinogen, D-dimer, Antithrombin, Thrombin Time, Factor VIII, and von Willebrand Factor, aspirin-induced platelet inhibition, adenosine-diphosphate test) changes during the study period. Fibrin Clot Permeability was evaluated using a pressure system and Permeability Coefficient (Ks) was calculated. We observed a decrease in fibrin clot permeability (Ks) between T1, T2, T3 and T4 time periods; P < 0.01 for each comparison. Fibrin clot permeability was negatively correlated with fibrinogen concentration: r = - 0.51, P < 0.001, factor VIII activity r = - 0.42, P < 0.001. There was no association of Ks with age, Left Ventricular Ejection Fraction (LVEF) and medications P > 0.001, however cumulative measurements in patients on aspirin showed shortening of Ks in this group P = 0.0123. Major adverse cardiac and cerebrovascular events (MACCE) occurred in 36.5% patients, bleeding events in 25.9%, Net Adverse Clinical Events (NACE) in 62.4%; 31.7% patients died, and 17.6% underwent transplantation. The transplantation was considered as the endpoint. Discrepancies in Ks were observed between patients with MACCE, bleeding, and NACE, and patients without adverse events. Ks showed a constant trend towards normalization (P < 0.01) only in patients without adverse events. Patients with advanced heart failure have disturbed clot structure. A trend towards normalization of the Ks values is associated with fewer thromboembolic and bleeding complications in this group of patients.

Fibrinogen post-translational modifications are biochemical determinants of fibrin clot properties and interactions.

The structure of fibrinogen and resulting fibrin formed during the coagulation process have important biological functions in human physiology and pathology. Fibrinogen post-translational modifications (PTMs) increase the complexity of the protein structure and many studies have emphasized the potential associations of post-translationally altered fibrinogen with the formation of a fibrin clot with a prothrombotic phenotype. However, the mechanisms by which PTMs exert their action on fibrinogen, and their causal association with disease pathogenesis are relatively unexplored. Moreover, the significance of fibrinogen PTMs in health has yet to be appreciated. In this review, the impact of fibrinogen PTMs on fibrinogen functionality is discussed from a biochemical perspective, emphasizing the potential mechanisms by which PTMs mediate the acquisition of altered fibrinogen properties. A brief discussion on dysfibrinogenemias of genetic origin, attributed to single point variations of the fibrinogen molecule is also provided, highlighting the influence that amino acid properties have on fibrinogen structure, properties, and molecular interactions that arise during thrombus formation.

Clot lysis time and thrombin generation in patients undergoing transcatheter aortic valve implantation.

BACKGROUND: Aortic valve stenosis (AS) is the most prevalent valvular heart disease and is associated with a significant increase in mortality. AS has been shown to be linked with numerous coagulation system abnormalities, including increased fibrin deposition on the stenotic aortic valves. Transcatheter aortic valve implantation (TAVI) is the primary treatment method for patients at high surgical risk. OBJECTIVES: The aim of the study was to assess the impact of treating severe AS with TAVI on thrombin generation and clot lysis time (CLT). METHODS: We studied 135 symptomatic AS patients recommended for TAVI by the local Heart Team. All measurements were performed before and 5-7 days after TAVI. Alongside clinical assessment and echocardiographic analysis, we assessed clot lysis time (CLT) and thrombin generation parameters, including lag time, peak thrombin generation, time to peak thrombin generation (ttPeak), and endogenous thrombin potential (ETP). RESULTS: 70 patients were included in the final analysis. After TAVI, there was a significant 9% reduction in CLT despite a 12% increase in fibrinogen concentration. We observed significant increase in lag time and ttPeak (20% and 12%, respectively), and 13% decrease in peak thrombin concentration compared to pre-procedural levels. Multivariable linear regression analysis demonstrated that baseline CLT and C-reactive protein (CRP) levels were independent predictors of significant reduction in mean aortic gradient, defined as TAVI procedure success. CONCLUSIONS: CLT and peak thrombin concentration decreased, while Lag time and ttPeak increased significantly after TAVI. Multivariable linear regression analysis demonstrated CLT and CRP levels as independent predictors of achieving a reduction in mean aortic gradient, defining TAVI procedure success.

Elevated plasma factor XI is associated with postthrombotic syndrome.

INTRODUCTION: Postthrombotic syndrome (PTS), a common complication of deep vein thrombosis (DVT), is largely inflammatory by nature with contribution of prothrombotic mechanisms. The role of factor (F)XI in PTS has not been explored yet. We investigated whether elevated FXI is associated with PTS occurrence. MATERIALS AND METHODS: We enrolled 180 consecutive patients (aged 43 ± 13 years) with first-ever DVT. After 3 months FXI levels were measured, along with inflammatory markers, thrombin generation, plasma clot permeability (Ks), clot lysis time (CLT), and fibrinolysis proteins. We assessed PTS using the Villalta score and recorded symptomatic venous thromboembolism (VTE) at a 1-year and venous ulcers at a median 53 months follow-up. RESULTS: Baseline median FXI was 102 % [IQR 92-113 %] and showed positive association with Villalta score (R = 0.474, P < 0.001). Patients with PTS (n = 48, 26.7 %) had 16.1 % higher FXI (P < 0.001) and FXI ≥120 % occurred more often in PTS patients (odds ratio [OR] 5.55, 95 % confidence interval [CI] 2.28-13.47). There were associations of baseline FXI with Ks and CLT along with thrombin activatable fibrinolysis inhibitor (TAFI) activity, C-reactive protein, and interleukin-6, but not with fibrinogen, or thrombin generation. After age adjustment higher FXI was independently associated with PTS occurrence (OR per 1 % 1.06, 95 % CI 1.02-1.09) and VTE recurrence (OR 1.03, 95 % CI 1.01-1.06). At long-term follow-up, patients with venous ulcers had 13.6 % higher baseline FXI (P = 0.002). CONCLUSIONS: Elevated FXI in association with inflammation and prothrombotic fibrin clot properties may contribute to the development of PTS following DVT.

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

INTRODUCTION: 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. METHODS: In 243 AF patients on anticoagulation (median age 69 years; 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 53 months. RESULTS: 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. CONCLUSION: 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.

Methods, precision, and analytical sensitivity of a novel low-plasma-volume assay of fibrinolytic capacity utilizing the euglobulin fraction.

INTRODUCTION: Fibrinolysis is a critical aspect of the hemostatic system, with assessment of fibrinolytic potential being critical to predict bleeding and clotting risk. We describe the method for a novel low-plasma-volume assay of fibrinolytic capacity utilizing the euglobulin fraction (the "modified mini-euglobulin clot lysis assay [ECLA]"), its analytic sensitivity to alterations in key fibrinolytic substrates/regulators, and its initial applications in acute and convalescent disease cohorts. METHODS: The modified mini-ECLA requires 50 µL of plasma, a maximal read time of 3 h (with most results available within 60 min), and is entirely performed in a 96-well microplate. Assay measurements were obtained in a variety of commercial control and deficient plasmas representing clinically relevant hypo- and hyperfibrinolytic states, and in three distinct adolescent cohorts with acute or convalescent illness: critically ill, following endotracheal intubation; acute COVID-19-related illness; and ambulatory, 3 months following a venous thromboembolic event. RESULTS: In 100% and 75% deficient plasmas, hypofibrinolysis for plasminogen-deficient, fibrinolysis for alpha-2-antiplasmin-deficient, and hyperfibrinolysis for plasminogen activator inhibitor-1-deficient plasmas were observed. CONCLUSION: The modified mini-ECLA Clot Lysis Time Ratio ("CLTR") demonstrated moderate-strength correlations with the Clot Formation and Lysis (CloFAL) assay, is analytically sensitive to altered fibrinolytic states in vitro, and correlates with clinical outcomes in preliminarily-studied patient populations.

Global coagulation assays detect an early prothrombotic state in children with acute lymphoblastic leukemia.

BACKGROUND: Pediatric patients with acute lymphoblastic leukemia (ALL) are at highest risk of venous thromboembolism during the induction therapy (IT). These events are not predictable by conventional coagulation assays. OBJECTIVES: To investigate the utility of global coagulation assays (GCAs) for assessing the hemostatic state in children with ALL during IT. METHODS: We included children with ALL (n = 15) and healthy controls (n = 15). Analyses were performed at different time points during IT of the AIEOP-BFM protocols. In addition to prothrombotic biomarkers, natural anticoagulant proteins, and in vivo thrombin generation (TG) markers, ex vivo TG was measured using the gold standard calibrated automated thrombogram method, automated ST Genesia, and thrombodynamics analyzer (TD). The latter also provided measurement of fibrin clot formation. RESULTS: Different from conventional coagulation assays and in vivo TG markers, ex vivo GCAs detected increasing prothrombotic changes during IT. Particularly, TG measured with TD as expressed by endogenous thrombin potential was already significantly elevated at days 8 to 12 (P < .01) and continued to increase during IT compared with prior to beginning treatment, indicating a very early shift toward a procoagulant state. A similar pattern was observed for the rate of fibrin clot formation (stationary rate of clot growth: P < .01 at days 8-12). Remarkably, in patients developing thrombotic complications (n = 5), both GCAs, ST Genesia and TD, showed a significantly higher endogenous thrombin potential very early (already at days 8-12, P < .05), well before clinical manifestation. CONCLUSION: GCAs capture prothrombotic changes early during IT in ALL pediatric patients. If confirmed, this approach will allow tailoring thromboprophylaxis in children with ALL at highest risk for venous thromboembolism.

SERPINE1 and MTHFR genetic variants in patients with embolic stroke of undetermined source: links with fibrin clot properties.

INTRODUCTION: The SERPINE1 c.-820G (4_5), MTHFR gene variants, and unfavourably altered fibrin clot features, have been suspected to be associated with embolic stroke of undetermined source (ESUS). We investigated the SERPINE1 c.-820G (4_5) gene variants alone and coexisting with MTHFR c.665C > T and c.1286A > C gene variants in relation to thrombophilic factors and plasma fibrin clot properties in Polish patients with ESUS. PATIENTS AND METHODS: Unrelated consecutive patients with ESUS (n = 206) were genotyped by TaqMan assay. Thrombophilia screening was performed four weeks or more after a thrombotic event while off oral anticoagulation. Factor VIII (FVIII) activity was determined by a coagulometric assay, while lipoprotein(a) was determined using immunoturbidimetry. We determined fibrin clot permeability (Ks) and clot lysis time (CLT). Apparently healthy individuals without a family history of stroke or venous thromboembolism (n = 30), and patients with a history of atrial fibrillation (n = 25) or carotid artery disease-related stroke (n = 21), served as controls. RESULTS: Among ESUS patients, the SERPINE1 c.-820G (4_5) minor allele frequency was 0.57. There were no differences in common factors associated with thrombophilia among ESUS patients regarding SERPINE1 variants. The overall prevalence of FVIII > 150IU/dL was 26% (n = 53) and elevated FVIII predominated in SERPINE1 variants carriers (n = 45; 84.9%), including 36 (68%) carriers of MTHFR variant. Moreover, 4.3-fold higher Lp(a) levels along with 50% reduced Ks and 46% prolonged CLT were found in patients with mutant SERPINE1 combined with mutant homozygotes in the MTHFR c.665C > T variant compared to the wild type SERPINE1 combined with mutant homozygotes in the MTHFR c.665C >T (P < 0.001). CONCLUSIONS: The SERPINE1 c.-820G (4_5) variants carriers have increased FVIII levels, while the SERPINE1 c.-820G (4_5) mutant homozygotes coexisting with MTHFR c.665C > T have more prothrombotic fibrin clot features and elevated Lp(a). Our study underlines the cumulative effect of genetic risk factors in patients with ESUS that might require specific antithrombotic therapy.

Altered fibrin clot phenotype in young adults with intracerebral hemorrhage of unknown cause: A case-control study.

BACKGROUND: Intracerebral hemorrhage (ICH) of undetermined etiology occurs infrequently in young and middle-aged adults. We hypothesized that slight decreases in coagulation factors and formation of less compact fibrin clots prone to faster lysis predispose to this type of ICH. METHODS: We recruited 44 consecutive patients aged <50 years following ICH of unknown cause at least 3 months since the event. Subjects free of ICH (n = 47) matched for age, sex, BMI, and hypertension served as the control group. We assessed plasma fibrin clot permeability, turbidity and fibrinolytic capacity, along with thrombin generation, coagulation factors (F) II, FV, FVII, FVIII, FIX, FX, FXI, antithrombin, and fibrinolysis proteins. RESULTS: ICH patients (median age 41 years, 45.5 % women) had 8.4 % lower FII (p = 0.0001) and 10.1 % lower FVII activity (p = 0.0003), 9.4 % higher antithrombin activity (p = 0.0004) and 13.5 % lower platelet count (p = 0.02). Other factors and thrombin generation did not differ between the two groups. The ICH survivors were characterized by impaired fibrin polymerization reflected by 10.1 % longer lag phase of the turbidimetry curve (p = 0.0002), decreased fiber density indicated by 11.8 % lower maximum absorbance (p = 0.004), as well as 11.1 % shorter clot lysis time (p = 0.014) and 10.0 % faster increase of maximal D-Dimer levels (p = 0.000001). CONCLUSIONS: We demonstrated a prohemorrhagic fibrin clot phenotype, along with lower FII, FVII and higher antithrombin activity in adults below 50 years of age who suffered from ICH of unknown cause, which might indicate novel mechanisms contributing to ICH in younger individuals.

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

INTRODUCTION: Spontaneous 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. METHODS: We 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). RESULTS: SEC/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. CONCLUSIONS: We 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.

Complement activation is associated with right ventricular dysfunction and the severity of pulmonary embolism: links with prothrombotic state.

Background: Little is known about the role of complement activation in acute pulmonary embolism (PE). We investigated whether complement activation is associated with the severity of acute PE, along with the associated prothrombotic state, systemic inflammation and neutrophil extracellular traps (NETs) formation. Methods: We studied 109 normotensive, non-cancer PE patients (aged 58.1±15.0 years). On admission prior to initiation of anticoagulation, plasma soluble complement components, i.e., C3a and sC5b-9, were measured with enzyme-linked immunosorbent assay (ELISA), along with thrombin generation, fibrinolysis proteins (plasminogen, antiplasmin, plasminogen activator inhibitor-1), factor VIII (FVIII) activity, and fibrin clot properties, including clot permeability (Ks, a measure of clot density) and clot lysis time (CLT). Moreover, we determined inflammatory markers and citrullinated histone H3, a specific marker of NETs formation. Results: Patients in the lower tertile of C3a (≤1.45 ng/mL, n=37) had lower simplified Pulmonary Embolism Severity Index (sPESI) values and were less likely to have right ventricular (RV) dysfunction compared to the remaining subjects. The former subgroup also had 13% lower FVIII activity, but not fibrinogen, interleukin-6, fibrinolysis proteins, and thrombin generation. Plasma C3a levels correlated inversely with Ks and positively with CLT indicating formation of denser and poorly lysable clots in subjects with elevated C3a. Despite a positive association between C3a and sC5b-9, the latter parameter was solely associated with higher FVIII, but not with other variables. Conclusions: We showed that in acute PE enhanced complement activation characterizes patients with poorer short-term prognosis who display prothrombotic fibrin clot properties and elevated FVIII, which supports the involvement of complement proteins in acute thromboembolism.

Homocysteine thiolactone and other sulfur-containing amino acid metabolites are associated with fibrin clot properties and the risk of ischemic stroke.

Homocysteine (Hcy) and Hcy-thiolactone (HTL) affect fibrin clot properties and are linked to cardiovascular disease. Factors that influence fibrin clot properties and stroke are not fully understood. To study sulfur-containing amino acid metabolites, fibrin clot lysis time (CLT) and maximum absorbance (Absmax) in relation to stroke, we analyzed plasma and urine from 191 stroke patients (45.0% women, age 68 ± 12 years) and 291 healthy individuals (59.7% women, age 50 ± 17 years). Plasma and urinary levels of sulfur-containing amino acid metabolites and fibrin clot properties were significantly different in stroke patients compared to healthy individuals. Fibrin CLT correlated with fibrin Absmax in healthy males (R2 = 0.439, P = 0.000), females (R2 = 0.245, P = 0.000), female stroke patients (R2 = 0.187, P = 0.000), but not in male stroke patients (R2 = 0.008, P = ns). Fibrin CLT correlated with age in healthy females but not males while fibrin Absmax correlated with age in both sexes; these correlations were absent in stroke patients. In multiple regression analysis in stroke patients, plasma (p)CysGly, pMet, and MTHFR A1298C polymorphism were associated with fibrin Absmax, while urinary (u)HTL, uCysGly, and pCysGly were significantly associated with fibrin CLT. In healthy individuals, uHTL and uGSH were significantly associated with fibrin Absmax, while pGSH, and CBS T833C 844ins68 polymorphism were associated with fibrin CLT. In logistic regression, uHTL, uHcy, pCysGly, pGSH, MTHFR C677T polymorphism, and Absmax were independently associated with stroke. Our findings suggest that HTL and other sulfur-containing amino acid metabolites influence fibrin clot properties and the risk of stroke.

Evaluation of Fibrin Clot Interaction with Dental Implant after Different Surface Treatments: An In Vitro Study.

AIM: The current study was carried out to assess the interaction between fibrin clots and dental implants following various surface treatments. MATERIALS AND METHODS: In this investigation, 45 dental implants with dimensions of 16 mm in length and 5 mm in diameter were utilized. They were divided up into three groups, each consisting of fifteen samples. Group I: Control; Group II: Ultraviolet (UV) light treated; and group III: Sandblasted and acid-etching (SLA) treated. Healthy volunteers' venous blood samples were drawn into vacutainer tubes without the use of anticoagulants. The samples were centrifuged for 3 minutes at 2700 rpm in a table centrifuge. The entire implant was submerged in room-temperature liquid fibrinogen for 60 minutes. Then, scanning electronic microscopy (SEM) was used to examine each sample. The inter- and intragroup assessments were obtained using the Mann-Whitney U test and the Kruskal-Wallis test; p-values less than 0.05 were regarded as statistically significant. RESULTS: The maximum adhesion of fibrin clot was found in SLA treated group (2.42 ± 0.10) followed by the UV light-treated group (2.18 ± 0.08) and control group (1.20 ± 0.02). There was a statistically significant difference found between the three surface-treated groups (p < 0.001). CONCLUSION: All surface-treatment methods exhibit adhesion between the implant surface and the fibrin clot. However, the highest adherence of fibrin clot was found in SLA treated group compared to the UV light-treated and control group. CLINICAL SIGNIFICANCE: The physical and chemical characteristics of an implant's surface have a significant impact on the way blood clots organize. At the interface between the implant and the bone, blood clot production can initiate and facilitate the healing process. How to cite this article: Jalaluddin M, Ramanna PK, Swain M, et al. Evaluation of Fibrin Clot Interaction with Dental Implant after Different Surface Treatments: An In Vitro Study. J Contemp Dent Pract 2024;25(3):276-279.

Association of Metallic and Nonmetallic Elements with Fibrin Clot Properties and Ischemic Stroke.

Objectives-Metallic elements and fibrin clot properties have been linked to stroke. We examined metallic and nonmetallic elements, fibrin clot lysis time (CLT), and maximum absorbance (Absmax) in relation to ischemic stroke. Design-A case-control study of ischemic stroke patients vs. healthy individuals. Subjects and Methods-Plasma and serum were collected from 260 ischemic stroke patients (45.0% women; age, 68 ± 12 years) and 291 healthy controls (59.7% women; age, 50 ± 17 years). Fibrin CLT and Absmax were measured using a validated turbidimetric assay. Serum elements were quantified by inductively coupled plasma mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES). Data were analyzed by bivariate correlations and multiple or logistic regression. Results-In female stroke patients, copper, lithium, and aluminum were significantly lower compared with controls; in male stroke patients, potassium was lower, and beryllium was elevated. In female and male stroke patients, iron, zinc, nickel, calcium, magnesium, sodium, and silicon were significantly lower, while strontium was elevated. Positive correlations between fibrin clot properties and metals, observed in healthy controls, were lost in ischemic stroke patients. In multivariate regression analysis, fibrin CLT and/or Absmax was associated with zinc, calcium, potassium, beryllium, and silicon in stroke patients and with sodium, potassium, beryllium, and aluminum in controls. In logistic regression analysis, stroke was independently associated with lithium, nickel, beryllium, strontium, boron, and silicon and with sodium, potassium, calcium, and aluminum but not with fibrin CLT/Absmax. Conclusions-Various elements were associated with fibrin clot properties and the risk of ischemic stroke. Lithium, sodium, calcium, and aluminum abrogated the association of fibrin clot properties with ischemic stroke.

Blood clot properties, thrombin generation, and platelet activation in patients with dysglycemia and established atherosclerotic cardiovascular disease: The CASCARA study.

BACKGROUND: There is a strong link between coronary artery disease (CAD), type 2 diabetes (T2D) on one hand, and altered fibrin clot properties, including increased clot density, and unfavorable fibrin clot structure on the other. T2D-related changes in fibrin clots can increase cardiovascular (CV) disease risk, including future CV events. We aimed to assess fibrin clot properties, thrombin generation, and platelet activation in CAD patients with prediabetes (PD) or T2D, compared to CAD patients without glycemic disorders. METHODS: We allocated patients to three groups: 1) Those with angiographically established CAD but without glycemic abnormalities (CAD group); 2) individuals with PD and established CAD (CAD+PD group); and 3) patients with T2D and CAD (CAD+T2D group). We conducted comparisons across these groups for thrombin generation, fibrin clot permeability, fibrin clot lysis, and platelet activation. RESULTS: The final analysis included 116 eligible patients: 1) CAD group (n = 31); 2) CAD+PD (n = 42); and 3) CAD+T2D (n = 43). The CAD+T2D patients enrolled had well-controlled T2D (median HbA1c level of 5.90%; IQR: 5.7%-6.3%). We found no significant differences in thrombin generation, fibrin clot properties, or platelet activation markers across the three analyzed groups (all P-values >0.20). However, elevated interleukin-6 (IL-6) levels were noted in both the highest and lowest glucose concentration quartiles. Additionally, a substantial increase in endogenous thrombin potential (ETP) was observed in patients in the highest glycated hemoglobin quintile. CONCLUSIONS: Individuals with established CAD and concomitant PD or well-controlled T2D exhibited comparable fibrin clot phenotypes, thrombin generation potential, and platelet activation when compared to CAD patients without dysglycemia.

A Fibrin-Thrombin Based In Vitro Perfusion System to Study Flow-Related Prosthetic Heart Valves Thrombosis.

Prosthetic heart valve (PHV) replacement has increased the survival rate and quality of life for heart valve-diseased patients. However, PHV thrombosis remains a critical problem associated with these procedures. To better understand the PHV flow-related thrombosis problem, appropriate experimental models need to be developed. In this study, we present an in vitro fibrin clot model that mimics clot accumulation in PHVs under relevant hydrodynamic conditions while allowing real-time imaging. We created 3D-printed mechanical aortic valve models that were inserted into a transparent glass aorta model and connected to a system that simulates human aortic flow pulse and pressures. Thrombin was gradually injected into a circulating fibrinogen solution to induce fibrin clot formation, and clot accumulation was quantified via image analysis. The results of valves positioned in a normal versus a tilted configuration showed that clot accumulation correlated with the local flow features and was mainly present in areas of low shear and high residence time, where recirculating flows are dominant, as supported by computational fluid dynamic simulations. Overall, our work suggests that the developed method may provide data on flow-related clot accumulation in PHVs and may contribute to exploring new approaches and valve designs to reduce valve thrombosis.

Fibrin clot fracture under cyclic fatigue and variable rate loading.

Fibrin clot is a vital class of fibrous materials, governing the mechanical response of blood clots. Fracture behavior of fibrin clots under complex physiological load is relevant for hemostasis and thrombosis. But how they fracture under cyclic and variable rate loading has not been reported. Here we conduct cyclic fatigue and monotonic variable rate loading tests on fibrin clots to characterize their fracture properties in terms of fatigue threshold and rate-dependent fracture toughness. We demonstrate that the fracture behavior of fibrin clots is sensitive to the amplitude of cyclic load and the loading rate. The cyclic fatigue tests show the fatigue threshold of fibrin clots at 1.66 J/m2, compared to the overall fracture toughness 15.8 J/m2. Furthermore, we rationalize the fatigue threshold using a semi-empirical model parameterized by 3D morphometric quantification to account for the hierarchical molecular structure of fibrin fibers. The variable loading tests reveal rate dependence of the overall fracture toughness of fibrin clots. Our analysis with a viscoelastic fracture model suggests the viscoelastic origin of the rate-dependent fracture toughness. The toughening mechanism of fibrin clots is further compared with biological tissues and hydrogels. This study advances the understanding and modeling of fatigue and fracture of blood clots and would motivate further investigation on the mechanics of fibrous materials. STATEMENT OF SIGNIFICANCE: Fibrin clot is a soft fibrous gel, exhibiting nonlinear mechanical responses under complex physiological loads. It is the main load-bearing constituent of blood clots where red blood cells, platelets and other cells are trapped. How the fibrin clot fractures under complex mechanical loads is critical for hemostasis and thrombosis. We study the fracture behavior of fibrin clots under cyclic fatigue and monotonic variable rate loads. We characterize the fatigue-threshold and viscous energy dissipation of fibrin clots. We compare the toughness enhancement of fibrin clots with hydrogels. The findings offer new insights into the fatigue and fracture of blood clots and fibrous materials, which could improve design guidelines for bioengineered materials.

Altered fibrin clot properties are associated with the progression of chronic kidney disease in atrial fibrillation.

INTRODUCTION: Formation of denser and resistant to lysis fibrin clot networks has been shown in chronic kidney disease (CKD) and atrial fibrillation (AF). We investigated whether such prothrombotic fibrin clot properties are associated with faster progression of CKD in AF patients. MATERIAL AND METHODS: We recruited 265 AF patients (men 49.1 %, median age of 64.0 years, median estimated glomerular filtration rate [eGFR] of 77.0 ml/min/1.73 m2), including 137 patients on non-vitamin K antagonist oral anticoagulants (NOACs) (51.7 %) and 109 patients (41.1 %) on vitamin K antagonists (VKAs). At baseline while off anticoagulation, we determined fibrin clot permeability (Ks), and clot lysis time (CLT), along with plasminogen activator inhibitor-1 (PAI-1), endogenous thrombin potential (ETP), and von Willebrand factor (vWF). The kidney function was assessed at baseline and after a median follow-up of 50.0 months. RESULTS: During follow-up, a median eGFR decreased by 8.0 (5.0-11.0) ml/min/1.73 m2, 1.8 ml/min/1.73 m2/year and this change correlated with age (R = 0.19, P = 0.002), Ks (R = 0.46, P < 0.0001), and CLT (R = -0.17, P = 0.005), but not ETP, fibrinogen, PAI-1 or vWF. A decrease in eGFR was lower in patients who used NOACs at baseline but not in those who started NOACs during follow-up (n = 101) as compared to the remaining patients. On multiple linear regression analysis, adjusted for age and fibrinogen, baseline Ks, eGFR, hypertension, and NOACs use independently predicted a decrease in eGFR. CONCLUSIONS: This study is the first to show that more compact fibrin clot networks may contribute to faster progression of CKD in AF, indicating novel kidney-related harmful effects of prothrombotic clot properties in humans.

Enhancing Meniscal Repair: Investigating the Impact of an Exogenous Fibrin Clot.

This study conducted a comparative analysis of meniscal rupture repair, evaluating outcomes with and without the application of an exogenous fibrin clot to enhance meniscus repair. The research incorporated a relatively large sample size (24 patients) and employed a randomized control group with similar age characteristics and morphological types of meniscal ruptures as the study group. Notably, two postoperative follow-up times, at the third and 12th postoperative months, were utilized, distinguishing this study from related research. In the third postoperative month assessment, the fibrin clot technique demonstrated a significant advantage over simple stapling, as evidenced by markedly improved Tegner Lysholm Knee Scoring Scale (TLKSS) and Modified Cincinnati Rating System Questionnaire (MCRSQ) clinical assessment scores. Subsequent MRI scans at 12 months post-treatment revealed a high rate (91.67%) of complete healing in menisci treated with a fibrin clot, with only 4.17% exhibiting incomplete healing. This study expanded on previous research by including longitudinal ruptures and bucket-handle ruptures in addition to radial ruptures. The findings highlight a notable early improvement (third postoperative month) in the clinical assessment of longitudinal and bucket-handle ruptures treated with a fibrin clot during meniscus repair. This research contributes valuable insights into the efficacy of fibrin clots in enhancing meniscus repair, suggesting positive clinical and radiological outcomes, especially in the early stages postoperatively.

Reduced fibrin clot permeability on admission and elevated E-selectin at 3 months as novel risk factors of residual pulmonary vascular obstruction in patients with acute pulmonary embolism.

BACKGROUND: Residual pulmonary vascular obstruction (RPVO) is common following pulmonary embolism (PE) but its association with fibrin clot properties is poorly understood. We investigated whether prothrombotic state and hypofibrinolysis markers can identify patients with RPVO. METHODS: In 79 normotensive noncancer patients (aged 56 ± 13.3 years) with acute PE, we determined fibrin clot permeability (Ks), clot lysis time (CLT), endogenous thrombin potential (ETP), fibrinolysis proteins, oxidative stress markers, and E-selectin on admission before initiation of anticoagulant therapy, after 5-7 days, and 3 months of anticoagulation. RPVO was diagnosed using computed tomography angiography 3-6 months since PE. RESULTS: Patients with RPVO (n = 23, 29.1%) had at baseline higher simplified Pulmonary Embolism Severity Index (sPESI) (P = 0.004), higher N-terminal brain natriuretic propeptide (P = 0.006) and higher D-dimer (P = 0.044). Patients with versus without RPVO had lower Ks (P < 0.001) and longer CLT (P < 0.05), both at baseline and 5-7 days since admission, but not at 3 months. Patients with RPVO showed 40.6% higher E-selectin (P < 0.001) solely at 3 months. By multivariable logistic regression, baseline Ks (odds ratio [OR] 0.010, 95% confidence interval [CI] 0.001-0.837, P = 0.042, per 10- 9 cm2), baseline D-dimer (OR 1.105, 95% CI 1.000-1.221, P = 0.049, per 100 ng/ml), and E-selectin levels after 3 months (OR 3.874, 95% CI 1.239-12.116, P = 0.020, per 1 ng/ml) were associated with RPVO. CONCLUSIONS: RPVO patients despite anticoagulation characterize with the formation of denser fibrin clots on admission and higher E-selectin at 3 months. Those parameters could be the potential novel RPVO risk factors that warrant further evaluation in an independent cohort.