This study was carried out in order to compare the coagulation balance in patients with colorectal cancer before and after surgical removal of tumor with an age matched non-malignancy control group. Furthermore, it was studied whether preoperative coagulation state in cancer patients was correlated to the postoperative development of deep venous thrombosis (DVT) diagnosed by venography. Plasma was collected preoperatively in 93 cancer patients and 30 controls, and postoperatively on day one, two, seven, and ninety in 88 cancer patients and <em>1</em>8 controls. <em>Prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>), thrombin-antithrombin complex (TAT), and total fibrin(ogen) degradation products (TDP) were quantitated in plasma by enzyme linked immunosorbent assays (ELISA). As compared to controls, patients admitted for cancer treatment displayed significantly higher levels of F<em>1</em> + <em>2</em> and TAT. Patients suffering from advanced colorectal cancer had significantly higher levels of TAT and TDP as compared to patients with localized colorectal cancer. Twenty-three percent of cancer patients developed DVT postoperatively. Preoperatively these patients displayed significantly higher TDP levels, and postoperatively higher levels of F<em>1</em> + <em>2</em>, TAT, and TDP compared to cancer patients without DVT. The marked activation of blood coagulation and fibrinolysis observed in all patients following major abdominal surgery was even more pronounced in patients not cured for cancer.

BACKGROUND

To increase middle molecule clearances, high-flux dialyzers with increased internal filtration have been developed. However, dialyzer design and structure may affect thrombin generation and platelet activation, thereby risking increased clotting and reduced dialyzer clearances.

METHODS

Coagulation parameters, platelet, white cell and endothelial activation markers were measured prior to and following dialysis sessions in <em>1</em><em>2</em> patients using two different dialyzers designed for increased internal filtration.

RESULTS

Prior to dialysis, patients had evidence of activation of coagulation with increased factor VIII:C, thrombin-antithrombin complexes and <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, increased platelet activation, with raised platelet factor 4, β-thromboglobulin levels and increased fibrinolysis (raised D-dimers). Dialysis was associated with the release of soluble platelet integrin, sP selectin, increased endothelial activation with increased levels of von Willebrand factor (vWF) antigen (vWF:Ag) and vWF propeptide (vWF:pp) and sE selectin. There was no difference in tinzaparin levels at the end of the dialysis session using either dialyzer, as shown by anti-Xa activity - 0.<em>1</em>45 ± 0.0<em>2</em>7 versus 0.<em>1</em><em>1</em> ± 0.0<em>1</em>7 IU/ml, respectively.

CONCLUSIONS

Haemodialysis patients have an inflammatory phenoytype, characterized by increased activation of coagulation, platelets and also fibrinolysis. However, dialyzers designed to increase internal filtration did not significantly increase platelet activation or thrombin generation.

BACKGROUND

A paradox seems to exist: exercising leads to clotting activation in conventional clotting tests, but exercising persons have a low risk of thrombosis. In this study we tried to evaluate the effect of exercise performance status on in vitro plasma thrombin generation, which represents an overall function test of hemostasis.

METHODS

We compared 56 trained subjects to 98 healthy age matched sedentary volunteers. Blood samples were analyzed for thrombin generation using calibrated automated thrombography. Microparticles were quantified using ELISA. Additionally <em>prothrombin</em> <em>fragments</em> <em>1</em> + <em>2</em>, thrombin-antithrombin complex, tissue factor pathway inhibitor, antithrombin and <em>prothrombin</em> were measured. The group of the trained subjects performed an incremental cycle-ergometer exercise test after taking the blood sample.

RESULTS

A significantly lower endogenous thrombin potential was observed in the group of the trained subjects compared to the sedentary individuals (p = 0.007). Microparticles (ELISA) were significantly lower in the trained subjects compared to the sedentary subjects (p = 0.00<em>1</em>). Prothrombin <em>fragments</em> <em>1</em> + <em>2</em> (p < 0.00<em>1</em>) and thrombin-antithrombin complex (p = 0.0<em>1</em>) were significant higher in the trained subjects and antithrombin (p = 0.0<em>2</em>) as well as <em>prothrombin</em> (p < 0.000<em>1</em>) were significantly lower in this group, whereas tissue factor pathway inhibitor values did not show significant differences. Both maximal and submaximal power output was significantly negatively related to endogenous thrombin potential (r = -0.43, r = -0.45) and thrombin peak (r = -0.44, r = -0.4<em>2</em>).

CONCLUSIONS

Trained subjects have a lower endogenous thrombin potential than sedentary subjects possibly explaining the lower incidence of thrombosis in this group despite a higher acute clotting activation during strenuous exercise.

Enhanced activation of the clotting system has been recently implicated in the pathogenesis of vascular complications in patients with diabetes mellitus. Abnormalities of the anticoagulant system may constitute a potential trigger factor for the haemostatic activation observed in diabetic subjects. The current study aimed to evaluate anticoagulant activity in diabetic patients by assessing the plasma levels of activated protein C-protein C inhibitor complex; and by measuring the anticoagulant response to exogenous thrombomodulin. This study comprised 6<em>1</em> patients (34 men, <em>2</em>7 women) with non-insulin-dependent diabetes mellitus (NIDDM) of whom <em>2</em><em>2</em> showed microalbuminuria and 39 normoalbuminuria. Data obtained in 3<em>1</em> non-obese and non-diabetic subjects were available for comparison. The plasma levels of fibrinogen (p < 0.0<em>2</em>), <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (p < 0.05), fibrin monomer (p < 0.000<em>1</em>), protein C antigen (p < 0.005), total protein S antigen (p < 0.0<em>2</em>), soluble thrombomodulin (p < 0.005) and soluble E-selectin (p < 0.005) were significantly higher in diabetic patients than in healthy subjects. The plasma level of activated protein C-protein C inhibitor complex (7.4 +/- 3.8 vs 3.0 +/- 0.4 pmol/l) was significantly higher (p < 0.000<em>1</em>) and the anticoagulant response to exogenous thrombomodulin (<em>2</em>3.4 +/- <em>2</em>.6 vs 35.3 +/- 3.0 ng/ml) was markedly lower (p = 0.005) in all diabetic patients than in healthy subjects. Cases with microalbuminuria presented low plasma levels of activated protein C-protein C inhibitor complex (5.5 +/- 0.6 vs 8.6 +/- 0.7 pmol/l, p < 0.05) and significantly decreased values of the anticoagulant response to exogenous thrombomodulin (<em>1</em>6.5 +/- <em>2</em>.9 vs <em>2</em>3.4 +/- <em>2</em>.6%, p = 0.03) as compared to those with normoalbuminuria. The present study suggests that the hyper-coagulable state in NIDDM is associated with an increased activation of protein C but with a poor plasma reactivity to the anticoagulant effect of thrombomodulin.

OBJECTIVE

This study compared rebound coagulation in patients with acute coronary syndrome patients after discontinuation of unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH).

BACKGROUND

Up to a quarter of patients hospitalized for unstable angina experience recurrent ischemia after discontinuation of UFH or LMWH therapy, which may be the result of rebound coagulation activation and subsequent thrombosis. It is unknown whether UFH and LMWH differ in this respect.

METHODS

We randomized 7<em>1</em> patients admitted with unstable angina to intravenous UFH or subcutaneous LMWH (dalteparin) and measured plasma markers of coagulation before, during, and after treatment.

RESULTS

A complete series of measurements was obtained in 59 patients. Plasma <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F(<em>1</em>+<em>2</em>)) levels decreased in both groups during treatment. After loss of therapeutic plasma drug levels, F(<em>1</em>+<em>2</em>) increased (within 3 h) to a maximum level at <em>1</em><em>2</em> to <em>2</em>4 h that was higher than before or during treatment in both groups (p < 0.000<em>1</em>). In both groups, F(<em>1</em>+<em>2</em>) levels remained higher than pretreatment up to <em>2</em>4 h after discontinuation. Similarly, thrombin-antithrombin (TAT) levels exceeded treatment and pretreatment levels, at a slower rate after dalteparin than after UFH. However, after dalteparin a higher peak value of TAT was observed.

CONCLUSIONS

Rebound coagulation activation occurs within hours after discontinuation of both UFH and dalteparin. With both drugs, thrombin generation is significantly greater after treatment than before or during treatment. A longer duration or weaning of treatment, or continuation with another anticoagulant treatment, may reduce rebound coagulation activation and ischemic events.

We have previously identified and characterized a potent and specific thrombin inhibitor, isolated from Bothrops jararaca, named bothrojaracin. Bothrojaracin interacts with the two positively charged recognition sites of thrombin referred to as exosite <em>1</em> and exosite <em>2</em>, whereas it does not interact with the thrombin active site. Consequently, bothrojaracin inhibits thrombin-induced fibrinogen to fibrin conversion and platelet activation, without inhibition of thrombin-catalyzed cleavage of small synthetic substrates. In the present study, we show that bothrojaracin exerts an anticoagulant effect in plasma, illustrated by the prolongation of the aPTT. Using purified proteins, we observed that the anticoagulant effect of bothrojaracin was not only due to the inhibition of fibrinogen to fibrin conversion, but in addition to the inhibition of factor V activation by thrombin. Bothrojaracin decreased the rate of thrombin-catalyzed proteolysis of factor V and concurrently the generation of factor Va cofactor activity measured in a <em>prothrombin</em>ase assay. We compared the effect of bothrojaracin with that of ligands binding specifically exosite <em>1</em> (hirudin C-terminal peptide SH54-65) or exosite <em>2</em> (heparin, <em>prothrombin</em> <em>fragment</em> <em>2</em>). SH54-65 delayed thrombin catalyzed factor V activation whereas heparin or <em>prothrombin</em> <em>fragment</em> <em>2</em> did not. The thrombin derivatives beta- and gamma-thrombin, which are defective in their exosite <em>1</em>, but present with a normally exposed exosite <em>2</em>, had a reduced capacity to activate factor V, which was not further impaired by the exosite <em>2</em> ligands, bothrojaracin, heparin or <em>prothrombin</em> <em>fragment</em> <em>2</em>. Altogether, our results provide further insight into the anticoagulant effect of bothrojaracin showing that it is a potent inhibitor of the feedback activation of factor V by thrombin, and thus of the up-regulation of its own production by thrombin. Inhibition of thrombin-catalyzed factor V activation by bothrojaracin is mainly mediated through the interaction of the inhibitor with thrombin exosite <em>1</em>, whereas contribution of the interaction with exosite <em>2</em> does not appear to play a direct role in factor V recognition by thrombin.

Essentials Complement, Toll-like receptors and coagulation cross-talk in the process of thromboinflammation. This is explored in a unique human whole-blood model of S. aureus bacteremia. Coagulation is here shown as a downstream event of C5a-induced tissue factor (TF) production. Combined inhibition of C5 and CD<em>1</em>4 efficiently attenuated TF and coagulation.

CONCLUSIONS

Background There is extensive cross-talk between the complement system, the Toll-like receptors (TLRs), and hemostasis. Consumptive coagulopathy is a hallmark of sepsis, and is often mediated through increased tissue factor (TF) expression. Objectives To study the relative roles of complement, TLRs and TF in Staphylococcus aureus-induced coagulation. Methods Lepirudin-anticoagulated human whole blood was incubated with the three S. aureus strains Cowan, Wood, and Newman. C3 was inhibited with compstatin, C5 with eculizumab, C5a receptor <em>1</em> (C5aR<em>1</em>) and activated factor XII with peptide inhibitors, CD<em>1</em>4, TLR<em>2</em> and TF with neutralizing antibodies, and TLR4 with eritoran. Complement activation was measured by ELISA. Coagulation was measured according to <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (PTF<em>1</em> + <em>2</em> ) determined with ELISA, and TF mRNA, monocyte surface expression and functional activity were measured with quantitative PCR, flow cytometry, and ELISA, respectively. Results All three strains generated substantial and statistically significant amounts of C5a, terminal complement complex, PTF<em>1</em> + <em>2</em> , and TF mRNA, and showed substantial TF surface expression on monocytes and TF functional activity. Inhibition of C5 cleavage most efficiently and significantly inhibited all six markers in strains Cowan and Wood, and five markers in Newman. The effect of complement inhibition was shown to be completely dependent on C5aR<em>1</em>. The C5 blocking effect was equally potentiated when combined with blocking of CD<em>1</em>4 or TLR<em>2</em>, but not TLR4. TF blocking significantly reduced PTF<em>1</em> + <em>2</em> levels to baseline levels. Conclusions S. aureus-induced coagulation in human whole blood was mainly attributable to C5a-induced mRNA upregulation, monocyte TF expression, and plasma TF activity, thus underscoring complement as a key player in S. aureus-induced coagulation.

Kringles <em>1</em> and 4 from human plasminogen are polypeptide domains of Mr approximately equal to <em>1</em>0000 each of which can be isolated by proteolysis of the zymogen. They have been studied by <em>1</em>H-NMR spectroscopy at 300 MHz and 600 MHz. The spectra, characteristic of globular structures, show striking analogies that point to a close conformational relatedness among the two kringles, consistent with their high degree of amino acid conservancy and homology. The interaction of both kringles with p-benzylaminesulfonic acid (BASA), an antifibrinolytic drug that binds to a lysine-binding site, results in better resolved, narrower lines for both spectra. Aromatic and methyl-region spectra of BASA complexes of kringles <em>1</em> and 4 were compared and the latter was studied by two-dimensional NMR spectroscopy. Analysis of the CH3 multiplets in terms of their resonance patterns, and the amino acid compositions and sequences of the two kringles, leads to the identification of most signals and to some assignments. In particular, a doublet at -<em>1</em> ppm, exhibited by both kringles and also found in reported proton spectra of homologous bovine <em>prothrombin</em> <em>fragments</em>, has been assigned to Leu46, a residue that is conserved in all of the kringles studied to date by <em>1</em>H-NMR. Since this resonance is somewhat more sensitive to BASA than other methyl signals, it is likely that Leu46 is proximal to the lysine-binding site. Nuclear Overhauser experiments reveal that Leu46 is surrounded by a cluster of closely interacting hydrophobic and aromatic side chains. Kringle 4 was also compared with a derivative chemically modified at Trp7<em>2</em> with dimethyl(<em>2</em>-hydroxy-5-nitrobenzyl)sulfonium bromide. As judged from the proton spectra, the modified kringle 4 retains globularity and is perturbed mainly in the aromatic region, in analogy to that which is observed for the unmodified kringle upon BASA binding. Furthermore, although previous studies have indicated no retention of the modified kringle by lysine-Sepharose, the NMR studies point to a definite interaction between BASA and the kringle derivative. The spectroscopic data also suggest that the His3<em>1</em> imidazole is not significantly affected by the ligand and that the lysine-binding site is structured mostly by hydrophobic side chains, including Trp7<em>2</em> in the case of kringle 4, and probably Tyr7<em>2</em> in kringle <em>1</em>.

BACKGROUND

Angiotensin (Ang) II may be involved in the development of cardiovascular disease. We examined the potential proinflammatory and prothrombotic effects of Ang II in <em>1</em>6 healthy subjects and in <em>1</em>6 subjects with familial combined hyperlipidemia (FCHL), a condition associated with an increased risk of cardiovascular complications.

METHODS

We studied the effects of a three hour intravenous infusion of Ang II (<em>1</em>0 ng/kg/min) on plasma concentrations of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), circulating leukocyte count, tissue plasminogen activator/plasminogen activator inhibitor-<em>1</em> (t-PA/PAI-<em>1</em>) complexes, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>), and thrombin-antithrombin (TAT) complexes. Blood was collected before, during and <em>1</em> h after Ang II infusion.

RESULTS

IL-6 was higher in subjects with FCHL at rest (P < 0.05) and increased (P < 0.00<em>1</em>) similarly in both groups by Ang II infusion. Also leukocyte count was higher in subjects with FCHL at rest (P < 0.00<em>1</em>) and increased (P < 0.00<em>1</em>) similarly in both groups by Ang II infusion. T-PA/PAI-<em>1</em> complexes were higher in subjects with FCHL at rest (P < 0.00<em>1</em>) and decreased (P < 0.00<em>1</em>) similarly in both groups during Ang II infusion. TNF-alpha, F<em>1</em>+<em>2</em> and TAT complexes were similar in the two groups at rest and did not change during or after the Ang II infusion.

CONCLUSIONS

A three hour Ang II infusion increases inflammation and may enhance fibrinolysis but does not affect short term thrombin generation. Subjects with FCHL have signs of increased inflammation and impaired fibrinolysis.

BACKGROUND

The changes in the activity of a number of plasma markers of coagulation and fibrinolysis have previously been studied in patients with ischemic stroke, with conflicting results. We aimed to find out the changes in the activities of a wide array of markers of the coagulation and the fibrinolytic system of mildly or moderately affected first-ever ischemic stroke patients.

METHODS

In a prospective, longitudinal, case-control study, we studied plasma plasminogen activator inhibitor type-<em>1</em> (PAI-<em>1</em>) activity, tissue-type plasminogen activator antigen (t-PA:Ag), d-dimer, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F <em>1</em>+<em>2</em>), and thrombin-antithrombin III complex (TAT) levels in 55 consecutive patients on admission, <em>1</em> week, <em>1</em> month, and 3 months after an ischemic stroke. Sex- and age-matched controls were studied once. All patients underwent blood sampling at each study time point; comprehensive stroke risk factors were recorded, and the etiology of the ischemic stroke was determined. All patients were contacted 3 years later for possible recurrent ischemic events.

RESULTS

PAI-<em>1</em> activity was increased in the acute phase and at 3 months, D-dimer levels were significantly higher at <em>1</em> week and <em>1</em> month after stroke, whereas t-PA:Ag, TAT and F <em>1</em>+<em>2</em> levels remained stable during the whole study period.

CONCLUSIONS

The changes of the fibrinolytic and coagulation system activity in the patients with mild or moderate ischemic stroke appeared minor compared with the results of previous studies, which included more severely ill patients.

Elevated plasma levels of fibrinogen and activated coagulation pathways are risk factors of cardiovascular disease in the general population. In a cross-sectional study of a case series, we investigated the relationship between fibrinogen and hemostatic markers with target-organ damage (TOD) in patients with arterial hypertension. <em>Prothrombin</em> time, partial thromboplastin time, fibrinogen, fibrin D-dimer, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>), and antithrombin III were measured in 35<em>2</em> untreated patients with mild to moderate essential hypertension and 9<em>2</em> normotensive controls. Staging of TOD was assessed according to W.H.O. guidelines by clinical evaluation and laboratory tests including measurements of creatinine clearance, proteinuria, ophthalmoscopy, electrocardiography, echocardiography, and ultrasound examination of major arteries. F<em>1</em>+<em>2</em> concentrations were significantly greater in hypertensive patients than normotensive controls and were positively correlated with blood pressure. Age, blood pressure levels, duration of hypertension, smoking, HDL-cholesterol, triglycerides, and plasma fibrinogen, fibrin D-dimer, and F<em>1</em>+<em>2</em> levels were significantly related to the presence and severity of TOD in univariate analysis. Plasma fibrinogen and D-dimer levels were related to organ damage independent of age, blood pressure, duration of hypertension, and smoking status. Separate analysis indicated significant association of fibrinogen and D-dimer levels with cardiac, cerebrovascular, peripheral vascular, and renal damage. In conclusion, elevated plasma levels of fibrinogen and a prothrombotic state are associated with the presence and severity of TOD in patients with essential hypertension and may contribute to the development of atherosclerotic disease in these patients.

OBJECTIVE

The prothrombotic state that occurs in uremic patients may increase their cardiovascular risk. We studied hypertensive patients with mild-to-moderate impairment of renal function to determine if they had evidence of abnormalities in the coagulation system.

METHODS

Renal function was assessed in 38<em>2</em> patients with essential hypertension, in whom <em>2</em>4-hour creatinine clearance, urinary protein excretion, and microalbuminuria were measured. We evaluated the function of the coagulation system by measurement of platelet counts, <em>prothrombin</em> time, partial thromboplastin time, and plasma antithrombin III, fibrinogen, D-dimer, and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> levels.

RESULTS

Impaired renal function, defined as a creatinine clearance of 30 to 89 mL per minute per <em>1</em>.73 m(<em>2</em>) of body surface area, was found in <em>1</em>68 (44%) of the patients. Age, blood pressure, duration of hypertension, and plasma levels of fibrinogen, D-dimer, <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>, and lipoprotein(a) were significantly greater in these patients than in those with normal renal function; these differences persisted after adjustment for potential confounders. Creatinine clearance was significantly and inversely correlated with levels of plasma fibrinogen (Spearman's rho = -0.<em>2</em>6, P <0.00<em>1</em>), D-dimer (rho = -0.33, P <0.00<em>1</em>), and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (rho = -0.<em>2</em>0, P <0.00<em>1</em>). Levels of plasma fibrinogen (P = 0.009) and D-dimer (P = 0.003) were correlated with renal function independent of age, blood pressure, duration of hypertension, triglyceride level, urinary protein excretion, and erythrocyte sedimentation rate. Lipoprotein(a) levels were correlated with fibrinogen (rho = 0.<em>1</em>6, P = 0.003) and D-dimer (rho = 0.<em>2</em>6, P <0.00<em>1</em>) levels.

CONCLUSIONS

Increased plasma levels of fibrinogen, D-dimer, and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> are present in hypertensive patients with mildly decreased creatinine clearance, suggesting that the coagulation system is activated in these patients.

In order to investigate the relationship between hemostatic abnormalities and portal vein thrombosis (PVT) in hepatocellular carcinoma (HCC), platelets, <em>prothrombin</em> time (PT), activated partial thromboplastin time (aPTT), thrombin time, fibrinogen, d-dimer, fibrinogen degradation products (FDPs), protein C, protein S, antithrombin, plasminogen, antiplasmin, coagulation factors (CFs) V, VII, VIII, IX, XI, and XIII, von Willebrand factor (vWF), <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (PF <em>1</em> + <em>2</em>), tissue-type plasminogen activator (tPA), and plasminogen activator inhibitor <em>1</em> (PAI-<em>1</em>) were studied in patients with HCC, cholangiocarcinoma, and metastatic liver tumors and in cirrhosis patients with or without PVT. Platelet, antithrombin, protein C, plasminogen, and CFs V, VII, IX, XI, and XIII levels of HCC group were found lower and PT, aPTT, thrombin time, vWF, FDPs, PF <em>1</em> + <em>2</em>, tPA, and PAI-<em>1</em> levels were higher than the control group. Our findings suggested that the abnormalities of coagulation and fibrinolysis systems have some role in provoking thrombosis of portal veins in HCC, in addition to the invasion of portal veins by hepatoma cells.

BACKGROUND

Hypertensive crisis is an extreme phenotype of hypertension and hypertension-related thrombotic complications. This is most evident in patients with hypertensive crisis having advanced retinopathy and thrombotic microangiopathy (TMA). We examined whether hypertensive crisis complicated by advanced retinopathy is associated with endothelial dysfunction, platelet activation, thrombin generation and decreased fibrinolytic activity. In addition, we tested the association between these procoagulant changes and the development of TMA and end-organ dysfunction.

METHODS

Several key mediators of coagulation were assessed in 40 patients with hypertensive crisis with and without retinopathy and compared with <em>2</em>0 age, sex and ethnicity-matched normotensive controls. In patients with hypertensive crisis, associations with markers of TMA and renal dysfunction were assessed by regression analysis.

RESULTS

Soluble P-selectin levels were higher in patients with hypertensive crisis compared with controls regardless of the presence or absence of retinopathy (P<0.0<em>1</em>). Levels of von Willebrand factor (VWF), VWF propeptide, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>) and plasmin-antiplasmin (PAP) complexes were significantly higher in hypertensive crisis with retinopathy compared with normotensive controls (P-values<0.0<em>1</em>), whereas in patients without retinopathy only VWF propeptide was higher (P=0.04). VWF, VWF propeptide, soluble tissue factor, F<em>1</em>+<em>2</em> and PAP were positively associated with markers of TMA and renal dysfunction (P≤0.05).

CONCLUSIONS

Hypertensive crisis with retinopathy confers a prothrombotic state characterized by endothelial dysfunction, platelet activation and increased thrombin generation, whereas fibrinolytic activity is enhanced. The observed changes in prothrombotic and antithrombotic pathways may contribute to the increased risk of ischaemic and haemorrhagic complications in this extreme hypertension phenotype.

BACKGROUND

Carbon dioxide pneumoperitoneum may be an important pathophysiological factor stimulating the coagulation system during conventional laparoscopic cholecystectomy. The aim of this study was to test the hypothesis that gasless laparoscopy produces smaller changes in the coagulation and fibrinolytic system than carbon dioxide pneumoperitoneum in patients undergoing laparoscopic cholecystectomy.

METHODS

Fifty patients were allocated randomly to conventional (n = <em>2</em>6) or gasless (n = <em>2</em>4) laparoscopic cholecystectomy. Blood samples were obtained on admission, after induction of anaesthesia, after insufflation or traction, 30 min after introduction of the laparoscope, <em>1</em>0 min after exsufflation of carbon dioxide or traction, 4 h after extubation and <em>2</em>4 h after operation.

RESULTS

The two groups were comparable with respect to age, sex, body mass index and duration of operation. Plasma levels of <em>prothrombin</em> <em>fragment</em> <em>1</em> and <em>2</em> (F<em>1</em> + <em>2</em>), soluble fibrin and D-dimer did not differ between the two groups. F<em>1</em> + <em>2</em> levels varied significantly in both groups during and after operation (P < 0.00<em>1</em>). Soluble fibrin and D-dimer levels did not change during operation in either group, but after operation the levels increased significantly in both groups (P < 0.00<em>1</em>).

CONCLUSIONS

Carbon dioxide pneumoperitoneum does not enhance the activation of coagulation and fibrinolysis associated with laparoscopic cholecystectomy. The coagulation and fibrinolytic systems are activated during and after gasless as well as conventional laparoscopic cholecystectomy.

BACKGROUND

There is growing evidence that indicates the presence of a prothrombotic state in atrial fibrillation (AF). However, the role of hemostatic markers in AF remains inconclusive.

METHODS

We conducted a meta-analysis of observational studies to evaluate the association between hemostatic markers and AF. A meta-regression was performed to explore potential sources of heterogeneity.

RESULTS

A total of 59 studies met our inclusion criteria for the meta-analysis. For platelet activation, increased circulating platelet factor-4, β-thromboglobulin (BTG) and P-selectin were significantly higher in AF cases compared with controls (standardized mean difference [SMD][95% confidence interval (CI)]: <em>1</em>.7<em>2</em>[0.96-<em>2</em>.49], <em>1</em>.6<em>1</em>[<em>1</em>.03-<em>2</em>.<em>1</em>9] and 0.50[0.<em>2</em>3-0.77], respectively). For coagulation activation, increased levels of plasma D-dimer, fibrinogen, thrombin-antithrombin, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, and antithrombin-III were significantly associated with AF (SMD[95% CI]: <em>1</em>.8<em>2</em>[<em>1</em>.38-<em>2</em>.<em>2</em>6], 0.7<em>2</em>[0.55-0.89], 0.4<em>2</em>[0.<em>1</em>3-0.7<em>2</em>], <em>1</em>.00 [0.00-<em>1</em>.99] and <em>1</em>.38[0.<em>1</em>6-<em>2</em>.60], respectively). For fibrinolytic function, tissue-type plasminogen activator and plasminogen activator inhibitor-<em>1</em> were significantly increased in AF cases compared with controls (SMD[95% CI]: 0.86[0.04-<em>1</em>.67] and 0.87[0.<em>2</em>8-<em>1</em>.47], respectively) but the associations became nonsignificant after performing subgroup analysis by anticoagulants treatment status. For endothelial function, increased von Willebrand factor was significantly associated with AF (SMD, 0.79; 95% CI, 0.60-0.99); however, no association was observed for soluble thrombomodulin (SMD, 0.60; 95% CI, -0.<em>1</em>3-<em>1</em>.33).

CONCLUSIONS

Increased circulating hemostatic factors (PF-4, BTG, P-selectin, D-dimer, fibrinogen, TAT, F<em>1</em>+<em>2</em>, AT- III, and vWf) are significantly associated with AF. Future research is necessary to elucidate the precise mechanism of the prothrombotic state and how hemostatic markers promote thromboembolism in AF.

Twenty-eight children with HSP and 79 healthy children were entered into study. Activities of protein C, free-protein S and antithrombin, activated protein C resistance, levels of fibrinogen. D-dimer, thrombin-antithrombin complex (TAT), <em>prothrombin</em> <em>fragments</em> <em>1</em> + <em>2</em> (PF(<em>1</em>+<em>2</em>)), and von Willebrand factor antigen (vWAg) and its activity (RiCof) were investigated in acute and recovery phases of HSP and controls. Fibrinogen, D-dimer, TAT, PF(<em>1</em>+<em>2</em>), vWAg, and RiCof levels in patients with HSP during the acute phase were significantly higher than those of recovery phase and of the controls. A significant correlation was detected between severity of disease and TAT, PF(<em>1</em>+<em>2</em>), vWAg, and D-dimer levels.

BACKGROUND

In the prospective, randomised, double-blind, placebo-controlled Regenerate Vital Myocardium by Vigorous Activation of Bone Marrow Stem Cells (REVIVAL)-<em>2</em> trial patients with acute myocardial infarction (AMI) and successful mechanical reperfusion received granulocyte-colony stimulating factor (G-CSF, 10 μg/kg KG s.c.) or placebo for 5 days. Aim of this substudy was to assess the impact of G-CSF on systemic inflammatory and procoagulant responses and platelet activation.

RESULTS

Before and five days after G-CSF (n=56) or placebo (n=58) circulating cytokine concentrations of interleukin (IL)-1ß, IL-6, IL-8, IL-10, IL-1<em>2</em> and Tumor-Necrosis Factor-α (TNF-α were measured. Prothrombin fragment F1+<em>2</em> and Tissue Factor activity served as a measure for activated coagulation. Platelet activation was characterized by cell surface expression of the activated fibrinogen receptor (PAC-1), P-selectin and CD40L by flow cytometry. Administration of G-CSF was associated with elevated TNF-α and CRP concentrations compared to the placebo group after 5 days. Other cytokines (IL-1ß, IL-6, IL-8, IL-10, IL-1<em>2</em>) were comparable after treatment with G-SCF or placebo. Similarly, circulating prothrombin fragments F1+<em>2</em>, TF activity and platelet activation did not differ in both groups.

CONCLUSIONS

Treatment with G-CSF in patients with AMI was associated with enhanced proinflammatory TNF-α and CRP levels but no activation of coagulation.

OBJECTIVE

Patients with a recent myocardial infarction have an increased risk of recurrent ischaemic events. In the ESTEEM trial, the oral direct thrombin inhibitor ximelagatran reduced the risk of new ischaemic events when compared with placebo in aspirin treated post myocardial infarction patients. Ximelagatran persistently reduced markers of coagulation activity, i.e. <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>) and D-dimer levels. The aim of this substudy was to evaluate the levels of these markers and activated thromboplastin time (APTT) in relation to new ischaemic events or bleeding.

RESULTS

In the substudy, 5<em>1</em>8 out of <em>1</em>883 patients were included and within <em>1</em>4 days after a myocardial infarction randomized to ximelagatran or placebo for 6 months. The clinical endpoints death, myocardial infarction, severe recurrent ischaemia, ischaemic stroke, and bleeding were evaluated. The levels of F<em>1</em> + <em>2</em>, D-dimer, and APTT were analysed at randomization and in serial samples during the study. Ximelagatran treatment appeared to have a larger treatment effect in patients with F<em>1</em> + <em>2</em> and D-dimer levels above the median at randomization with a reduction of ischaemic events from <em>1</em>8 to 9% (P = 0.03) for F<em>1</em> + <em>2</em> and from <em>2</em>0 to 9% for D-dimer (P = 0.009). A reduction of D-dimer levels was found in 60% of the patients <em>1</em> week after randomization and these patients had less ischaemic events when compared with patients with unchanged or increased levels (P = 0.03) regardless of treatment. F<em>1</em> + <em>2</em> and D-dimer levels were unrelated to bleeding risk. In the ximelagatran group, increased APTT was not related to ischaemic events but associated with a raised risk of bleeding.

CONCLUSIONS

A reduction of initially high coagulation activity, as measured by the D-dimer level, in patients with recent myocardial infarction identifies patients with a decreased risk of new ischaemic events, regardless whether the reduction occurs spontaneously or is induced by pharmacological means. Patients with higher initial coagulation activity seemed to benefit most from long-term treatment with ximelagatran.

A role of coagulation in the pathogenesis of aortic stenosis (AS) is unknown. The aim of this study was to investigate the fibrin (Fn) presence and its determinants in calcified stenotic aortic valve leaflets. Twenty-one patients with dominant AS and <em>1</em>7 well-matched patients with dominant aortic insufficiency (AI) undergoing aortic valve replacement were studied. Immunofluorescence analysis was performed on decalcified leaflets using antibodies against human Fn and tissue factor (TF). Fn-positive (4<em>1</em>.4%) and TF-positive (<em>2</em>5.3%) areas were increased in AS valves compared with AI valves (7.9% and 5.9%, respectively, both p<0.00<em>1</em>). Patients with AS had elevated plasma D-dimer (<em>2</em>36.4 ± <em>2</em>8 ng/ml, p=0.00<em>2</em>) and <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>.<em>2</em>) (<em>2</em>6<em>1</em>.7 ± <em>2</em>7.<em>1</em> pM, p=0.005) compared to AI subjects (<em>1</em>4<em>2</em>.8 ± <em>1</em>0 ng/ml and <em>1</em>3<em>1</em>.<em>2</em> ± <em>1</em>.3 pM, respectively). In AS patients Fn-positive areas correlated with TF-positive areas (r=0.68, p=0.0005), D-dimer (r=0.45, p=0.0<em>1</em>8), F<em>1</em>.<em>2</em> (r=0.64, p=0.00<em>2</em>), the time required for plasma fibrin clot formation (r=0.44, p=0.0<em>1</em>5) and maximum absorbance of fibrin clots (r=-0.38, p<0.000<em>1</em>), but not with clot permeability or lysis time. Thickness of Fn layer within AS valves was associated with maximum transvalvular gradient (r =0.4<em>1</em>, p=0.048). Patients with maximal gradient above 75 mmHg (n=<em>1</em><em>1</em>) showed significant associations between Fn-positive area and both maximal (r =0.63) and mean (r =0.67) transvalvular gradients. Large fibrin amounts, mostly co-localised with TF, are present within the valve leaflets of patients with advanced AS. In vivo thrombin generation and fibrin clot formation are associated with the extent of Fn presence within leaflets, which might contribute to the AS progression.

BACKGROUND

Recently released studies indicate that activation of blood coagulation may be involved in causing urticaria.

OBJECTIVE

To evaluate whether or not anticoagulation, fibrinolysis and the complement system are also involved in the pathogenesis of urticaria.

METHODS

Coagulant factors, anticoagulant factors, fibrinolytic markers and complement components were analysed in patients with acute urticaria (AU) and chronic urticaria (CU). Conclusion: The activation of coagulation, anti-coagulation, fibrinolysis and the complement system may be involved in the pathogenesis of urticaria. It also indicates that coagulation conditions in CU patients can recover after antihistamine treatment, but do not immediately return to normal levels directly after administration.

RESULTS

Plasma levels of activated factor VII (FVIIa) were higher in AU patients (P <0.0<em>1</em>) but not significantly different in CU patients (P >0.05), while levels of the thrombin-antithrombin complex (TAT) and <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>) were significantly higher in CU patients (P <0.0<em>1</em>). Levels of factor IX (FIX) and tissue factor (TF) were lower in CU patients (P <0.0<em>1</em>). Plasma levels of tissue factor pathway inhibitor/activated factor X (TFPI/Xa) were higher in CU patients (P <0.0<em>1</em>) but not significantly different in AU patients (P >0.05), whereas levels of thrombomodulin (TM) were lower in CU patients (P <0.0<em>1</em>). Plasma levels of D-dimer in AU and CU patients and levels of high molecular weight kininogen (HMWK) in CU patients were increased significantly (P <0.0<em>1</em>), while levels of tissue-type plasminogen activator (t-PA) were decreased (P <0.0<em>1</em>). Plasma concentrations of C5a in CU patients were superior to those in healthy controls (P <0.0<em>1</em>). Serum levels of C4 also increased (P <0.0<em>1</em>).

CONCLUSIONS

The activation of coagulation, anti-coagulation, fibrinolysis and the complement urticaria. It also indicates that coagulation conditions in CU patients can recover after antihistamine treatment, but do not immediately return to normal levels directly after administration.

OBJECTIVE

Disturbances in hemostasis are common findings in uremic patients. Both bleeding diathesis and thrombosis are observed. The purpose of this study was to assess whether renal replacement therapy in the form of hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD) affects coagulation and fibrinolysis in patients with end-stage renal failure.

METHODS

Comparison of hemostatic measures in patients on CAPD, HD, and matched healthy controls.

METHODS

Department of Nephrology and Internal Medicine, Bialystok University School of Medicine.

METHODS

Twenty-four HD patients and <em>2</em>3 CAPD patients were evaluated with respect to platelet aggregation, hemostatic parameters, serum lipids, lipoprotein(a), and cytokines [tumor necrosis factor alpha (TNFalpha) and interleukin-<em>1</em> (IL-<em>1</em>)].

METHODS

Four exchanges of CAPD per day, using <em>2</em>.0 L dialysate over a period of <em>2</em>5 +/- 3<em>1</em> months; or 4-5 hours of HD 3 times per week for a period of 3<em>1</em> +/- <em>2</em><em>2</em> months.

RESULTS

Platelet aggregation in whole blood and platelet-rich plasma was significantly impaired in both groups of dialyzed patients compared to healthy volunteers. Markers of endothelial cell injury (thrombomodulin and von Willebrand factor) were significantly higher in HD and CAPD patients compared to the control group. A similar pattern of changes was observed for lipoprotein(a), fibrinogen, tissue factor pathway activity, and factor VII activity. Activity of factor X was significantly enhanced in CAPD compared to HD patients and controls. Euglobulin clot lysis time was significantly prolonged in HD and CAPD patients over controls, being more prolonged in CAPD patients. Markers of ongoing coagulation (thrombin-antithrombin complexes and <em>prothrombin</em> <em>fragments</em> <em>1</em>+<em>2</em>) were higher in uremic patients, significantly higher in CAPD than in HD. A marker of ongoing fibrinolysis (plasmin-antiplasmin complexes) was higher in uremic patients but was lower in CAPD than in HD patients. Concentrations of TNFalpha and IL-<em>1</em> were higher in HD than in CAPD patients.

CONCLUSIONS

Patients on CAPD showed evidence of a higher degree of hypercoagulation than HD patients.Thus, hemostatic abnormalities in end-stage renal failure may be affected to some extent by the choice of renal replacement therapy.

OBJECTIVE

Patients receiving long-term anticoagulant treatment with dabigatran may need to undergo a percutaneous coronary intervention (PCI). We studied markers of coagulation activation during elective PCI in patients using dabigatran in order to investigate whether coagulation activation upon balloon inflation and stenting is suppressed by dabigatran without additional heparin treatment.

RESULTS

This phase IIa, exploratory, multicentre, randomised, open-label study included 50 stable patients having an elective PCI. Patients on standard dual antiplatelet therapy (DAPT) were randomised (<em>2</em>:<em>2</em>:<em>1</em>) to either pre-procedural dabigatran <em>1</em><em>1</em>0 mg BID (n=<em>1</em>9) or <em>1</em>50 mg BID (n=<em>2</em><em>1</em>), as compared to standard intraprocedural unfractionated heparin (UFH) (n=<em>1</em>0). Following PCI, a significant increase in the levels of <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>) in the combined dabigatran group was observed compared to the level just before the start of PCI (<em>1</em>59.<em>1</em> [<em>1</em>.4] pmol/l; geometric mean [gSD]). Levels at 0.5, <em>1</em>.0, <em>1</em>.5 and <em>2</em> hrs after the start of PCI ranged from <em>1</em>93.5 (<em>1</em>.4) to <em>2</em>70.6 pmol/l (<em>1</em>.7); (p-value for paired analysis=0.0<em>1</em>5, 0.0<em>2</em><em>2</em>, 0.<em>2</em>34<em>2</em>, 0.0379, respectively). Also, thrombin-antithrombin (TAT) complexes were increased significantly in the combined dabigatran group compared to pre-PCI levels (4.<em>2</em> [<em>2</em>.<em>2</em>] ug/l). Levels ranged from 5.<em>2</em> (<em>2</em>.5) to 8.5 (<em>2</em>.3) (p=0.0497, 0.0343, 0.005 and 0.<em>1</em>6<em>2</em>8, respectively). In contrast, in the control group of patients treated with UFH, no increase was observed in F<em>1</em>+<em>2</em> and TAT complexes during PCI. Five out of 40 (<em>1</em><em>2</em>.5%) patients required bail-out anticoagulation in the dabigatran group, of whom four experienced a procedural myocardial infarction (MI), versus one out of <em>1</em>0 in the UFH group, who had a stent thrombosis without MI prior to the study-PCI. One minor access-site bleeding occurred in the dabigatran group.

CONCLUSIONS

Dabigatran treatment (<em>1</em><em>1</em>0 mg or <em>1</em>50 mg BID) may not provide sufficient anticoagulation during PCI. EudraCT. No: <em>2</em>007-007536-<em>2</em>5.

<strong class="sub-title"> Introduction: </strong> Patients with COVID-<em>1</em>9 are known to have a coagulopathy with a thrombosis risk. It is unknown whether this is due to a generalized humoral prothrombotic state or endothelial factors such as inflammation and dysfunction. The aim was to further characterize thrombin generation using a novel analyser (ST Genesia, Diagnostica Stago, Asnières, France) and a panel of haematological analytes in patients with COVID-<em>1</em>9.

<strong class="sub-title"> Methods: </strong> Platelet poor plasma of 34 patients with noncritical COVID-<em>1</em>9 was compared with 75 patients with critical COVID-<em>1</em>9 (as defined by WHO criteria) in a retrospective study by calibrated automated thrombography and ELISA. Patients were matched for baseline characteristics of age and gender.

<strong class="sub-title"> Results: </strong> Critical patients had significantly increased fibrinogen, CRP, interleukin-6 and D-dimer compared to noncritical patients. Thrombin generation, in critical patients, was right shifted without significant differences in peak, velocity index or endogenous thrombin potential. Tissue plasminogen activator (tPA), tissue factor pathway inhibitor (TFPI) and vascular endothelial growth factor (VEGF) were significantly increased in the critical versus noncritical patients. Critically ill patients were on haemodiafiltration (3<em>1</em>%; heparin used in the circuit) or often received escalated prophylactic low-molecular weight heparin.

<strong class="sub-title"> Conclusion: </strong> These results confirm increased fibrinogen and D-dimer in critical COVID-<em>1</em>9-infected patients. Importantly, disease severity did not increase thrombin generation (including thrombin-antithrombin complexes and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>) when comparing both cohorts; counter-intuitively critical patients were hypocoaguable. tPA, TFPI and VEGF were increased in critical patients, which are hypothesized to reflect endothelial dysfunction and/or contribution of heparin (which may cause endothelial TFPI/tPA release).

<strong class="sub-title"> Keywords: </strong> COVID-<em>1</em>9; thrombin generation; thrombosis; tissue factor pathway inhibitor; tissue plasminogen activator.