BACKGROUND

Tissue factor pathway inhibitor (TFPI) is the endogenous inhibitor of the extrinsic coagulation pathway; however, its involvement during thrombus formation in patients with acute coronary syndromes (ACS) is still unknown.

RESULTS

Transcardiac (aorta/coronary sinus) free and total TFPI (free + lipoprotein-bound form) levels, as well as TFPI/factor Xa (FXa) complex levels, were measured in plasma samples obtained from patients with acute myocardial infarction undergoing primary PTCA and patients with unstable angina undergoing urgent PTCA. Patients with stable angina undergoing elective PTCA served as controls. In addition, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> and fibrinopeptide A plasma levels were measured. Samples were collected at baseline, after PTCA, and after stent deployment. In patients with ACS, both total and free TFPI plasma levels in the coronary sinus were significantly lower than the corresponding levels measured in the aorta at any time point of the study; conversely, a significant increase in TFPI/FXa complex plasma levels was observed in the coronary sinus as compared with the aorta. In contrast, in patients with stable angina, no differences were observed in TFPI and TFPI/FXa levels at baseline in the coronary sinus as compared with the aorta.

CONCLUSIONS

TFPI is involved in the process of thrombus formation in vivo in patients with ACS, which suggests a potential role for TFPI in modulating coronary thrombosis.

BACKGROUND

Traumatic brain injury (TBI) and hemorrhagic shock (HS) can be associated with coagulopathy and inflammation, but the mechanisms are poorly understood. We hypothesized that a combination of TBI and HS would disturb coagulation, damage the endothelium, and activate inflammatory and complement systems.

METHODS

A total of 33 swine were allocated to either TBI + HS (n = <em>2</em>7, TBI and volume-controlled 40% blood loss) or controls (n = 6, anesthesia and instrumentation). TBI + HS animals were left hypotensive (mean arterial pressure, 30-35 mm Hg) for <em>2</em> hours. Blood samples were drawn at baseline, 3 minutes and <em>1</em>5 minutes after injury, as well as following <em>2</em> hours of hypotension. Markers of coagulation, anticoagulation, endothelial activation/glycocalyx shedding, inflammation, complement, and sympathoadrenal function were measured.

RESULTS

The TBI + HS group demonstrated an immediate (3 minutes after injury) activation of coagulation (<em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>, <em>2</em>89 ng/mL vs. <em>2</em>3<em>2</em> ng/mL, p = 0.03) and complement (C5a, <em>2</em>.83 ng/mL vs. <em>2</em>.05 ng/mL, p = 0.05). Shedding of the endothelial glycocalyx (syndecan <em>1</em>) was evident <em>1</em>5 minutes after injury (85<em>1</em>.0 ng/ml vs. 7<em>1</em>5.5 ng/ml, p = 0.03) while inflammation (tumor necrosis factor α [TNF-α], 8<em>1</em>.<em>1</em> pg/mL vs. 50.8 pg/mL, p = 0.03) and activation of the protein C system (activated protein C, 56.7 ng/mL vs. <em>2</em>6.<em>1</em> ng/mL, p = 0.0<em>1</em>) were evident following the <em>2</em>-hour hypotension phase.

CONCLUSIONS

The combination of TBI and shock results in an immediate activation of coagulation and complement systems with subsequent endothelial shedding, protein C activation, and inflammation.

Granulocyte colony-stimulating factor (G-CSF) is used in healthy donors of peripheral blood stem cells (PBSC) for allogeneic transplantation. However, some data have recently suggested that G-CSF may induce a hypercoagulable state, prompting us to study prospectively <em>2</em><em>2</em> PBSC donors before and after G-CSF 5 microg/kg twice daily. We sought evidence for changes in the following parameters: platelet count, von Willebrand factor antigen (vWF:Ag) and activity (vWF activity), beta-thromboglobulin (beta-TG), platelet factor 4 (PF-4), platelet activation markers (GMP-<em>1</em>40 and PAC-<em>1</em>), activated partial thromboplastin time (aPTT), <em>prothrombin</em> time (PT), coagulant factor VIII (FVIII:C), thrombin-antithrombin complex (TAT), <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>), thrombomodulin (TM) and tissue plasminogen activator antigen (tPA:Ag) prior to G-CSF and immediately before leukapheresis. ADP-induced platelet aggregation studies were also performed. G-CSF administration produced only mild discomfort. We found a significant increase in vWF:Ag (from 0.99 +/- 0.3<em>2</em> U/ml to <em>1</em>.83 +/- 0.69 U/ml; P < 0.00<em>1</em>), in vWF activity (from <em>1</em>.04 +/- 0.34 U/ml to <em>1</em>.78 +/- 0.50 U/ml; P < 0.00<em>1</em>) and in FVIII:C (from <em>1</em>.<em>1</em><em>2</em> +/- 0.37 U/ml to <em>1</em>.73 +/- 0.57 U/ml; P < 0.00<em>1</em>) after G-CSF. Of note, four donors with low baseline vWF had a two- to three-fold increase after receiving G-CSF. G-CSF had no impact on the platelet count, beta-TG, PF-4, GMP-<em>1</em>40 or PAC-<em>1</em>. The final% of platelet aggregation decreased from 73 +/- <em>2</em><em>2</em>% to 37 +/- <em>2</em>6% after G-CSF (P < 0.00<em>1</em>). We found a significant decrease in aPTT after G-CSF (<em>2</em>9.9 +/- 3.<em>1</em> s to <em>2</em>8.3 +/- 3.3 s; P = 0.004), but the PT was unaffected. In addition, we also observed a significant increase in TAT, F<em>1</em>+<em>2</em> and TM, but not in tPA:Ag. Our data suggest that G-CSF may possibly induce a hypercoagulable state by increasing levels of FVIII:C and thrombin generation. In contrast to this information, we found reduced platelet aggregation after G-CSF administration. The clinical implications of these findings remain unclear and larger studies are definitely required.

Hip joint replacement surgery, using acrylic cement for prosthesis fixation, is associated with intraoperative cardiorespiratory dysfunction, and a high frequency of postoperative proximal deep vein thrombosis (DVT). Levels of <em>prothrombin</em> <em>fragments</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>), tissue plasminogen activator antigen (t-PA), plasminogen activator inhibitor <em>1</em> activity (PAI-<em>1</em>), D-dimer and interleukin 6 (IL-6) were measured in arterial (AB) and mixed venous blood (MVB) in five patients during and after total hip replacement operation with acrylic cement prosthesis fixation. Sequential peaks of F<em>1</em>+<em>2</em>, t-PA, PAI-<em>1</em> and IL-6 appeared, starting with activation of coagulation during preparation of bone, closely followed by activation of fibrinolysis. Later, this was counteracted by an antifibrinolytic response and increase of IL-6. After a fibrinolytic shutdown on the third postoperative day as evidenced by a drop in t-PA and D-dimer concentrations, a second wave of coagulation was seen at the end of the first week. The present model, with frequent sampling of blood entering and leaving the lungs, confirms our earlier findings of the lung as a key organ in promoting coagulation following traumatic activation.

OBJECTIVE

The metabolic syndrome is associated with proinflammatory and prothrombotic states. This study was designed to assess the behaviour of soluble CD40 ligand (sCD40L) and <em>prothrombin</em> <em>fragment</em> F (<em>1</em>+<em>2</em>), a marker of thrombin generation, in patients with the metabolic syndrome.

METHODS

We investigated <em>1</em>06 patients with the metabolic syndrome, diagnosed according to the ATPIII report, and <em>1</em>04 subjects without the metabolic syndrome.

RESULTS

Plasma values of sCD40L and F (<em>1</em>+<em>2</em>) were higher in patients with the metabolic syndrome (4.<em>1</em><em>1</em>+/-<em>1</em>.64 vs <em>2</em>.6<em>1</em>+/-0.89 ng/ml and <em>1</em>.54+/-0.49 vs 0.87+/-0.<em>2</em><em>1</em> nmol/l, respectively; p < 0.00<em>1</em>) and were significantly correlated (r = 0.9<em>2</em>5, p < 0.00<em>1</em>). Stepwise multiple linear regression analysis showed that sCD40L was significantly associated with F (<em>1</em>+<em>2</em>), female sex and waist circumference.

CONCLUSIONS

Patients with the metabolic syndrome have enhanced values of plasma sCD40L and F (<em>1</em>+<em>2</em>). The study provides further insight into the relationship between metabolic syndrome, inflammation and thrombosis.

It remains to be debated whether traumatic brain injury (TBI) induces a different coagulopathy than does non-TBI. This study investigated traditional coagulation tests, biomarkers of coagulopathy, and endothelial damage in trauma patients with and without TBI. Blood from 80 adult trauma patients was sampled (median of 68 min [IQR 48-88] post-injury) upon admission to our trauma center. Plasma/serum were retrospectively analyzed for biomarkers reflecting sympathoadrenal activation (adrenaline, noradrenaline), coagulation activation/inhibition and fibrinolysis (protein C, activated protein C, tissue factor pathway inhibitor, antithrombin, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, thrombin/antithrombin complex, von Willebrand factor, factor XIII, d-dimer, tissue-type plasminogen activator, plasminogen activator inhibitor-<em>1</em>), immunology (interleukin [IL]6), endothelial cell/glycocalyx damage (soluble thrombomodulin, syndecan-<em>1</em>), and vasculogenesis (angiopoietin-<em>1</em>, -<em>2</em>). Patients were stratified according to: (<em>1</em>) isolated severe head/neck injuries (Abbreviated injury score [AIS]-head/neck ≥ 3, AIS-other<3) (isoTBI); (<em>2</em>) severe head/neck and extracranial injuries (AIS-head/neck ≥ 3, AIS-other>3) (sTBI+other); and (3) injuries without significant head/neck injuries (AIS-head/neck<3, including all AIS-other scores) (non-TBI). Twenty-three patients presented with isoTBI, <em>1</em>5 with sTBI+other and 4<em>2</em> with non-TBI. Acute coagulopathy of trauma shock, defined as activated partial thromboplastin time (APTT) and/or international normalized ratio (INR)>35 sec and><em>1</em>.<em>2</em>, was found in <em>1</em>3%, 47%, and 5%, respectively (p=0.000). sTBI+other had significantly higher plasma levels of adrenaline, noradrenaline, annexin V, d-dimer, IL-6, syndecan-<em>1</em>, soluble thrombomodulin, and reduced protein C and factor XIII levels (all p<0.05). No significant biomarker differences were found between isoTBI and non-TBI patients. Injury severity scale (ISS) rather than the presence or absence of head/neck injuries determined the hemostatic and biomarker response to the injury. The coagulopathy identified thus reflected the severity of injury rather than its localization.

Vascular complications are the main cause of morbidity in diabetes mellitus. To evaluate lipoprotein and hemostatic parameters and their relationship with clinically detectable microangiopathy, we studied 58 insulin-dependent diabetes mellitus patients and 60 controls matched for age, sex, and body mass index. Thirteen patients presented clinically detectable microangiopathy (8 retinopathy and 5 both retinopathy and microalbuminuria). A cross-sectional study of lipid profile, coagulation parameters, and a flow-cytometric evaluation of tissue factor expression in normal monocytes induced by patient plasma were performed. Patients were re-evaluated for microangiopathy in a 3-year median follow-up. Patients showed triglyceride enrichment in low (P = 0.0000<em>2</em>) and high density lipoproteins (P = 0.004) and increased levels of D-dimer (P < 0.0000<em>1</em>), <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (P < 0.0000<em>1</em>), and thrombin-antithrombin III complex (P = 0.000<em>1</em>). Patients with clinically detectable microangiopathy had increased type <em>1</em> plasminogen activator inhibitor (P = 0.0000<em>1</em>), thrombomodulin (P = 0.0<em>2</em>), and induced monocyte tissue factor expression (P < 0.0000<em>1</em>). Nine patients developed clinically detectable microangiopathy in the follow-up and the only predictive variable was increased induced tissue factor expression. In conclusion, in these patients elevated thrombin and fibrin generation reflects a hypercoagulable state but clinically detectable microangiopathy seems related to endothelial cell injury markers and to increased induced tissue factor expression on monocytes.

Because human studies concerning the effects of stearic acid on thrombotic tendency are inconsistent, we compared the effects of stearic acid with those of its unsaturated derivatives, oleic acid and linoleic acid. In this randomized, crossover study, 45 subjects (<em>2</em>7 women and <em>1</em>8 men) consumed, in random order, 3 experimental diets, each for 5 wk. Diets contained approximately 38% of energy as fat. Dietary compositions were the same except for 7% of energy from stearic, oleic, or linoleic acids. At the end of each period, ex vivo and in vitro platelet aggregation, and variables of coagulation, fibrinolysis, and hematology were evaluated. In men, ex vivo platelet aggregation time as measured by filtragometry (P = 0.036 for diet effects) was favorably prolonged during consumption of the linoleic acid diet compared with the stearic acid diet (P = 0.040), but there was no difference with consumption of the oleic acid diet (P = 0.<em>1</em>98). In vitro platelet aggregation induced by collagen and ADP, and variables of coagulation (factor VII amidolytic activity and concentrations of fibrinogen and <em>prothrombin</em> <em>fragment</em> <em>1</em> and <em>2</em>) and fibrinolysis [plasminogen activator inhibitor (PAI) activity and concentrations of tissue plasminogen activator (tPA)/PAI-<em>1</em> complexes] did not differ among the 3 diets. The mean platelet volume of the subjects decreased during consumption of the stearic acid diet by 0.3<em>2</em> fL compared with the oleic acid diet (P < 0.00<em>1</em>) and by 0.35 fL compared with the linoleic acid diet (P < 0.00<em>1</em>). In conclusion, our results do not suggest that stearic acid is highly thrombogenic compared with oleic and linoleic acids.

BACKGROUND

Diurnal fluctuations of blood coagulation and fibrinolysis activity are thought to play a role in the observed circadian variation in the frequency of onset of acute cardiovascular events. In the present study, the diurnal variations in blood coagulation and fibrinolysis activity were investigated in <em>1</em>0 young, healthy control subjects by use of specific molecular activation markers.

RESULTS

The plasma levels of activated factor FVII (FVIIa), the active portion of the main coagulation activator, decreased during the day (8 AM: <em>2</em>.03 ng/mL, CI <em>1</em>.<em>1</em>6 to <em>2</em>.88 ng/mL; 8 PM: <em>1</em>.<em>1</em>6 ng/mL, CI 0.8<em>1</em> to <em>1</em>.5 ng/mL; P = .005), whereas FVII antigen did not change significantly. In parallel with the diurnal variations of FVIIa, we found a decrease of <em>prothrombin</em> <em>fragment</em> F<em>1</em>+<em>2</em> (8 AM: 0.97 nmol/L, CI 0.79 to <em>1</em>.<em>1</em>5 nmol/L; 8 PM: 0.78 nmol/L, CI 0.64 to 0.93 nmol/L; P = .005), a molecular marker of intravasal thrombin generation. Evidence for a possible functional relevance of circulating FVIIa was found because this parameter was significantly correlated with <em>prothrombin</em> <em>fragment</em> F<em>1</em>+<em>2</em> in 7<em>2</em> fasting healthy individuals (r = .<em>2</em>9, P = .0<em>1</em><em>1</em>). Plasminogen activator inhibitor-<em>1</em> levels decreased (8 AM: 9.9 ng/mL, CI 7.7 to <em>1</em><em>2</em>.<em>1</em> ng/mL; 8 PM: 5.4 ng/mL, CI 3.8 to 6.9 ng/mL; P < .005), whereas plasmin-plasmin inhibitor complex levels, representing the degree of intravascular plasmin generation, concomitantly increased (8 AM: <em>2</em>35 micrograms/L, CI <em>1</em>98 to <em>2</em>7<em>2</em> micrograms/L; 8 PM: 449 micrograms/L, CI 39<em>1</em> to 507 micrograms/L; P = .008).

CONCLUSIONS

Our data suggest that the diurnal changes in the plasma levels of activators and inhibitors of coagulation and fibrinolysis lead to corresponding changes in the activity state of these systems, leading to morning hypercoagulability and hypofibrinolysis.

Circular dichroism experiments indicate that <em>prothrombin</em> <em>fragment</em> <em>1</em> undergoes essentially the same secondary structural change whether in the presence of Ca(<em>2</em>+), Mg(<em>2</em>+), or Mn(<em>2</em>+). Titration with any of these metal ions results in a sigmoidal titration curve indicative of cooperative binding. Mg(<em>2</em>+) and Ca(<em>2</em>+) have nearly identical transition midpoints, while that for Mn(<em>2</em>+) is an order of magnitude less. These results correlate well with the results of previous metal ion intrinsic fluorescence quenching experiments. <em>Fragment</em> <em>1</em> has previously been shown to undergo a second transition corresponding to dimerization at high calcium concentrations. The present circular dichroism experiments show that this transition does not result in a gross alteration of secondary structure in the <em>fragment</em> <em>1</em> molecule. Studies with <em>prothrombin</em>, similar to those with <em>fragment</em> <em>1</em>, indicate a similar metal ion dependent conformational change but of smaller magnitude. As apparently only the <em>fragment</em> <em>1</em> portion of the molecule undergoes the transition, it would appear that the covalently linked <em>fragment</em> <em>1</em> is constrained from attaining the same conformation as the purified entity. This suggests that caution must be used in interpreting the results of metal ion binding studies using <em>fragment</em> <em>1</em> as an analogue for <em>prothrombin</em>.

The interplay between inflammatory and hemostatic mechanisms may play a crucial role in the development and progression of atherosclerosis. The authors evaluated the separate and joint associations of hemostatic and inflammatory variables on peripheral atherosclerotic progression in the Edinburgh Artery Study, a population cohort study of <em>1</em>,59<em>2</em> men and women aged 55-74 years that started in <em>1</em>987. Levels of fibrinogen, fibrin D-dimer, von Willebrand factor, tissue plasminogen activator antigen, factor VII, <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>, urinary fibrinopeptide A, C-reactive protein, and interleukin-6 were measured at baseline. Arm and ankle blood pressures were measured, and atherosclerotic progression was assessed by computing ankle brachial index (ABI) at baseline (<em>1</em>,58<em>2</em> participants) and after <em>1</em><em>2</em> years of follow-up (8<em>1</em>3 participants). Fibrinogen (p = 0.05) and D-dimer (p < or = 0.05) were significantly associated with ABI change independently of baseline ABI and cardiovascular disease risk factors. However, these associations were no longer significant when analyses were adjusted for either C-reactive protein or interleukin-6. Moreover, subjects with higher levels of both D-dimer and interleukin-6 at baseline had the greatest ABI decline. In conclusion, fibrinogen and D-dimer, but not other hemostatic factors, were associated with progressive peripheral atherosclerosis. Since D-dimer and fibrinogen are acute phase reactants, these data support the hypothesis that inflammation is more related to atherosclerosis than is hypercoagulation.

BACKGROUND

The pathogenesis of chronic spontaneous urticaria (CU) has recently been conceived to be associated with thrombin generation through the extrinsic coagulation pathway. However, little is known about the components of the intrinsic coagulation pathway potentially involved.

METHODS

To investigate the whole process of coagulation, both classical coagulation assays and a global coagulation test, the intrinsic coagulation pathway-dependent activated partial thromboplastin time (APTT) clot waveform analysis, were performed using plasma of 36 patients with CU who had various severities.

RESULTS

Classical coagulation assays revealed that levels of fibrinogen, D-dimer, and fibrin and fibrinogen degradation products (FDP), and positive rates of soluble fibrin monomer complex (SFMC) were significantly elevated in patients with CU, whereas the elevation of <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> was not statistically significant. On the other hand, all parameters of a global coagulation test, APTT clot waveform analysis, evidently showed a hypercoagulable pattern and were significantly correlated to disease severity of CU.

CONCLUSIONS

CU is characterized by elevated blood coagulation potential with involvement of the intrinsic coagulation factors, which may contribute in vivo to the generation of fibrin even by small amounts of thrombin.

During sepsis, lipopolysaccharide (LPS) triggers the development of disseminated intravascular coagulation (DIC) via the tissue factor-dependent pathway of coagulation resulting in massive thrombin generation and fibrin polymerization. Recently, animal studies demonstrated that hirudin reduced fibrin deposition in liver and kidney and decreased mortality in LPS-induced DIC. Accordingly, the effects of recombinant hirudin (lepirudin) was compared with those caused by placebo on LPS-induced coagulation in humans. Twenty-four healthy male subjects participated in this randomized, double-blind, placebo-controlled, parallel group study. Volunteers received <em>2</em> ng/kg LPS intravenously, followed by a bolus-primed continuous infusion of placebo or lepirudin (Refludan, bolus: 0.<em>1</em> mg/kg, infusion: 0.<em>1</em> mg/kg/h for 5 hours) to achieve a <em>2</em>-fold prolongation of the activated partial thromboplastin time (aPTT). LPS infusion enhanced thrombin activity as evidenced by a <em>2</em>0-fold increase of thrombin-antithrombin complexes (TAT), a 6-fold increase of polymerized soluble fibrin, termed thrombus precursor protein (TpP), and a 4-fold increase in D-dimer. In the lepirudin group, TAT increased only 5-fold, TpP increased by only 50%, and D-dimer only slightly exceeded baseline values (P <.0<em>1</em> versus placebo). Concomitantly, lepirudin also blunted thrombin generation evidenced by an attenuated rise in <em>prothrombin</em> <em>fragment</em> levels (F(<em>1</em> + <em>2</em>), P <. 0<em>1</em> versus placebo) and blunted the expression of tissue factor on circulating monocytes. This experimental model proved the anticoagulatory potency of lepirudin in LPS-induced coagulation activation. Results from this trial provide a rationale for a randomized clinical trial on the efficacy of lepirudin in DIC. (Blood. <em>2</em>000;95:<em>1</em>7<em>2</em>9-<em>1</em>734)

Orthostatic stress activates the coagulation system. The extent of coagulation activation with full orthostatic load leading to presyncope is unknown. We examined in 7 healthy males whether presyncope, using a combination of head up tilt (HUT) and lower body negative pressure (LBNP), leads to coagulation changes as well as in the return to baseline during recovery. Coagulation responses (whole blood thrombelastometry, whole blood platelet aggregation, endogenous thrombin potential, markers of endothelial activation and thrombin generation), blood cell counts and plasma mass density (for volume changes) were measured before, during, and <em>2</em>0 min after the orthostatic stress. Maximum orthostatic load led to a <em>2</em>5% plasma volume loss. Blood cell counts, <em>prothrombin</em> levels, thrombin peak, endogenous thrombin potential, and tissue factor pathway inhibitor levels increased during the protocol, commensurable with hemoconcentration. The markers of endothelial activation (tissue factor, tissue plasminogen activator), and thrombin generation (F<em>1</em>+<em>2</em>, <em>prothrombin</em> <em>fragments</em> <em>1</em> and <em>2</em>, and TAT, thrombin-antithrombin complex) increased to an extent far beyond the hemoconcentration effect. During recovery, the markers of endothelial activation returned to initial supine values, but F<em>1</em>+<em>2</em> and TAT remained elevated, suggestive of increased coagulability. Our findings of increased coagulability at <em>2</em>0 min of recovery from presyncope may have greater clinical significance than short-term procoagulant changes observed during standing. While our experiments were conducted in healthy subjects, the observed hypercoagulability during graded orthostatic challenge, at presyncope and in recovery may be an important risk factor particularly for patients already at high risk for thromboembolic events (e.g. those with coronary heart disease, atherosclerosis or hypertensives).

OBJECTIVE

To determine whether activation of coagulation increases in parallel with inflammation and whether coagulation activation markers (CAMs) are independently associated with coronary heart disease (CHD), in the prospective study, NPHSII.

METHODS

Surveillance of <em>2</em>997 men between 50 and 63 years yielded 3<em>1</em>4 first CHD events during 36507 person-years of observation. The plasma levels of activated factor XII (FXIIa), the peptides released upon activation of factor X (FXpep) and factor IX (FIXpep), activated factor VII (FVIIa), <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>) and fibrinopeptide A (FpA) served as indices of activity along the coagulation pathway. C reactive protein (CRP) provided a marker of inflammatory activity.

RESULTS

While borderline or significant correlations were identified for each CAM with inflammation, as determined by CRP levels, these did not reach as high a numerical value as was shown for fibrinogen with CRP. FVIIa and FIXpep possessed independent associations with CHD: a one SD increase in adjusted FIXpep and FVIIa level was associated with a relative hazard of <em>1</em>.<em>2</em>0 (95% CI <em>1</em>.00-<em>1</em>.43) and 0.70 (CI 0.58-0.86), respectively, using a group including all CHD events, compared with 'no-event'.

CONCLUSIONS

Inflammation has significant but minimal impact upon CAMs of the extrinsic coagulation pathway. Reduced FVIIa and increased FIXpep levels were found to be significant, independent, predictors of CHD.

BACKGROUND

Heart failure (HF) is associated with a hypercoagulable state that predisposes to thromboembolism and anti-coagulation may improve clinical outcomes. The oral, direct Factor Xa inhibitor, rivaroxaban, has not been studied in patients with HF. We hypothesized that rivaroxaban would also reduce biomarkers of hypercoagulability in patients with HF.

METHODS

This study consisted of two cohorts: Cohort <em>1</em>, open-label, actively controlled with enoxaparin 40 mg once daily, included 8 patients with acute decompensated HF; Cohort <em>2</em>, double-blind and placebo-controlled, included <em>1</em>8 patients with stable, severe New York Heart Association Class III/IV HF.

RESULTS

The pharmacokinetics (PK) and pharmacodynamics (PD) of rivaroxaban were similar across both cohorts. Biomarker assessments were performed in Cohort <em>2</em>; prothrombin fragment <em>1</em>.<em>2</em> (F<em>1</em>.<em>2</em>) mean concentration decreased by <em>2</em>.7 ng/ml over 7 days with rivaroxaban, and increased by <em>1</em><em>1</em>.6 ng/ml with placebo, an absolute difference of <em>1</em>4.3 ng/ml (p = 0.0009). A non-significant reduction in rate of increase of D-dimer (DD) and thrombin-anti-thrombin complex (TAT) levels with rivaroxaban was observed over 7 days (p = 0.3<em>1</em> and p = 0.77, respectively).

CONCLUSIONS

Rivaroxaban has similar PK/PD in patients with either acute or chronic HF. In vivo, hypercoagulability biomarkers appear to increase over time. Rivaroxaban reversed this trend for F<em>1</em>.<em>2</em>, and may reduce the rate of increase of DD and TAT in patients with stable, severe HF.

BACKGROUND

Antithrombin III (AT III) treatment has been shown to reduce disseminated intravascular coagulation and to inhibit thrombin, which plays a central role in the activation of platelets and other inflammatory systems in conditions with severe inflammation. The objective of this study was to evaluate the influence of early and high-dose administration of AT III to patients with severe multiple injuries on the inflammatory response and outcome.

METHODS

In a placebo-controlled, double-blind study, 40 consecutive patients with Injury Severity Scores of <em>2</em>9 or greater who met the inclusion criteria were randomized to receive either AT III or placebo within 360 minutes after trauma. Twenty patients were administered AT III for a period of 4 days, aiming to achieve AT III concentrations of <em>1</em>40% of normal.

RESULTS

The AT III and placebo groups were comparable with respect to Injury Severity Score, age, incidence of blood pressure less than 80 mm Hg on admission, initial base deficit, and start of the test drug. The patients in the AT III group received a total of about <em>2</em>0,000 IU during the first 4 days. AT III levels of <em>1</em>30 to <em>1</em>40% could be achieved by this regimen, whereas in the control group the AT III concentration averaged about 70%. In the AT III group <em>prothrombin</em> tended to be elevated and <em>prothrombin</em> <em>fragment</em> F<em>1</em>+<em>2</em> as well as thrombin-AT III complex tended to be lower on the first day. No differences between groups, however, could be observed with respect to partial thromboplastin time, <em>prothrombin</em> time, platelets, plasminogen activator inhibitor I, soluble tumor necrosis factor receptor II, neutrophil elastase, interleukin (IL)-<em>1</em> receptor antagonist, IL-6, and IL-8. Mortality (<em>1</em>5 vs. 5%), incidence of respiratory failure (55 vs. 55%), duration of mechanical ventilation (<em>1</em>3 vs. <em>1</em><em>2</em> days), and length of stay in the surgical intensive care unit (<em>1</em>9 vs. <em>2</em><em>1</em> days) were also similar in both treatment groups. The duration of organ failure, however, was shorter in the patients receiving AT III.

CONCLUSIONS

The early and high-dose administration of AT III to patients with severe blunt trauma appears not to attenuate the posttraumatic inflammatory response or to significantly improve outcome.

To determine the prevalence of the factor V Leiden gene mutation in relation to the phenotypes of cerebral infarction and cerebral hemorrhage, we studied 386 randomly selected cases of acute stroke and <em>2</em>47 control subjects. Factor V genotype was determined by amplification of a <em>2</em>67-bp sequence of exon/intron <em>1</em>0 of the factor V gene. Levels of <em>prothrombin</em> <em>fragment</em> F(<em>1</em> + <em>2</em>), a marker of thrombin generation, were determined in both acute and convalescent stroke and related to factor V genotype. <em>Prothrombin</em> <em>fragment</em> F(<em>1</em> + <em>2</em>) was assessed by using an enzyme-linked immunosorbent assay. Sixteen stroke cases (4.<em>1</em>%) were identified as having the mutation compared with <em>1</em>4 (5.6%) control subjects. <em>Prothrombin</em> <em>fragment</em> F(<em>1</em> + <em>2</em>) levels were estimated in <em>1</em>9<em>1</em> cases and found to be elevated both acutely and after 3 months, but they were not related to factor V genotype. <em>Prothrombin</em> <em>fragment</em> F(<em>1</em> + <em>2</em>) is elevated in acute stroke and requires further evaluation in relation to cerebrovascular disease. These results suggest that the factor V Leiden gene mutation is not a risk factor for arterial thrombosis causing stroke.

OBJECTIVE

To determine the success rate of percutaneous ultrasonographically (US) guided thrombin injection in the treatment of femoral pseudoaneurysms and to evaluate the effects of thrombin injection on systemic coagulation parameters.

METHODS

Fifty femoral pseudoaneurysms (37 simple pseudoaneurysms with one lobe and <em>1</em>3 complex pseudoaneurysms with two or three lobes) were treated with US-guided percutaneous thrombin injections. Pseudoaneurysm size, neck length and width, thrombin dose, outcome of therapy, and complications were documented prospectively. Duplex sonographic follow-up examinations were performed at <em>1</em><em>2</em>-<em>2</em>4 hours and 5-7 and <em>2</em><em>1</em>-<em>2</em>5 days. In <em>2</em>5 patients, activated thromboplastin time, Quick test (<em>prothrombin</em> time), thrombin time, fibrinogen, D-dimer, antithrombin III, thrombin-antithrombin III complex, and <em>prothrombin</em> <em>fragments</em> <em>1</em> and <em>2</em> were determined before and at <em>2</em>, 5, and <em>1</em>0 minutes after thrombin injection. Differences in results before and those after thrombin injection were evaluated by means of the one-sample t test.

RESULTS

Mean volume of pseudoaneurysms was 5.84 cm(3) +/- 4.89 (SD). Fifty-eight thrombin injections were performed. Mean thrombin dose was 357 IU +/- <em>2</em>9<em>1</em> in simple and 638 IU +/- 549 in complex pseudoaneurysms. Primary success rate was 36 of 37 (97%) for simple and eight of <em>1</em>3 (6<em>1</em>%) for complex pseudoaneurysms. Reperfusion occurred in four complex pseudoaneurysms (none in simple ones). Secondary success rate was <em>1</em>00%. No thromboembolic, infectious, or allergic complications occurred. During follow-up, reperfusion was detected in one patient with a complex pseudoaneurysm. Levels of thrombin-antithrombin III complex increased significantly (P <.05) after thrombin injection, whereas changes in all other laboratory tests were not significant.

CONCLUSIONS

US-guided percutaneous injection of thrombin is successful and safe in the management of femoral pseudoaneurysms. The increase of thrombin-antithrombin III complex indicates the possibility of thrombin passage into the arterial circulation.

BACKGROUND

The optimal anticoagulant regimen for percutaneous coronary intervention (PCI) remains to be determined. Otamixaban, a selective and direct inhibitor of factor Xa, was investigated in patients undergoing nonurgent percutaneous coronary intervention.

RESULTS

In this double-blind, double-dummy, parallel-group, dose-ranging trial, 947 patients were randomly assigned to either <em>1</em> of 5 weight-adjusted otamixaban regimens or weight-adjusted unfractionated heparin (UFH) before percutaneous coronary intervention. The primary end points were change in <em>prothrombin</em> <em>fragments</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>), and anti-factor Xa activity. The main secondary end points were Thrombolysis In Myocardial Infarction (TIMI) bleeding at day 3 or hospital discharge (whichever came first) and 30-day ischemic events. The median change in F<em>1</em>+<em>2</em> from baseline to the end of infusion was greater with the highest otamixaban dose compared with UFH (-0.3 versus -0.<em>2</em> ng/mL, P=0.008). Anti-factor Xa levels were 65, <em>1</em>55, 393, 57<em>1</em>, and 69<em>1</em> ng/mL with otamixaban doses <em>1</em> to 5, respectively. Significant TIMI bleeding (major or minor) occurred in <em>2</em>.0%, <em>1</em>.9%, 3.8%, 3.9%, and <em>2</em>.6% of patients receiving otamixaban doses <em>1</em> to 5, respectively, and in 3.8% of patients receiving UFH. Four TIMI major bleeds were observed. Ischemic events occurred in 5.8%, 7.<em>1</em>%, 3.8%, <em>2</em>.5%, and 5.<em>1</em>% of patients receiving otamixaban doses <em>1</em> to 5, respectively, and in 5.6% of patients receiving UFH.

CONCLUSIONS

Otamixaban reduced F<em>1</em>+<em>2</em> significantly more than UFH at the highest dose regimen, whereas no significant difference in the incidence of TIMI bleeding was observed between the otamixaban and UFH groups. These results set the stage for adequately powered clinical outcome trials of selective direct factor Xa inhibition in patients with acute coronary syndromes.

The normal aging process alters blood coagulation system in humans; this may be of great concern in the view of the known association of vascular disease with advancing age. The plasma concentration of several coagulation factors, namely fibrinogen, factor VII, factor VIII, factor IX, high molecular-weight kininogen, and prekallikrein, increase in healthy humans, paralleling the physiological aging process. Plasma parameters of clotting activation in vivo, such as <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>, fibrinopeptide A, thrombin-antithrombin III complex, and D-dimer, are positively correlated with age. Nevertheless, among centenarians, biochemical signs of marked hypercoagulability are associated with a healthy state. Natural anticoagulants, including antithrombin III, heparin cofactor II, protein C, protein S, and tissue factor pathway inhibitor, can modulate the reactions of blood coagulation system. The occurrence of menopause is accompanied by a significant increase in antithrombin III plasma level; the mean antithrombin III levels in older women exceed levels in male contemporaries. In healthy elderly subjects heparin cofactor II plasma concentrations are lower than in young subjects, independently of gender. Protein C levels raise with age in both sexes, as well as free protein S levels. In women, statistically significant increases in the plasma concentration of the tissue factor pathway inhibitor have been observed, whereas no significant age-related change has been found in men. The fact that many subjects with congenital defects of natural anticoagulants do not undergo thromboembolic events in young age suggests that in healthy individuals a raise in natural anticoagulants can balance the age-related increase of procoagulant factors.

OBJECTIVE

The authors studied the coagulation cascade and fibrinolysis pathway in patients with untreated glaucoma (P = 0.0000<em>1</em> and P = 0.0003, respectively) and patients with normal pressure glaucoma ([NPG] P = 0.0000<em>1</em> and P = 0.03, respectively).

METHODS

Forty-two untreated patients with NPG, <em>2</em>5 untreated patients with primary open-angle glaucoma (POAG), and 3<em>2</em> age-matched normal controls were recruited. Patients taking anticoagulant therapy beta blockers or calcium channel blockers were excluded. Venous blood was assessed for markers of the coagulation and fibrinolysis pathways using enzyme-linked immunosorbent assay techniques.

RESULTS

Patients with POAG had elevated levels of <em>prothrombin</em> <em>fragments</em> <em>1</em> + <em>2</em> and D-dimer compared with both the NPG and controls (P = 0.0000<em>1</em> and P = 0.0003, respectively). Both glaucoma groups had more (P < 0.05) systemic vascular disease than the control group. The patients with POAG had higher (P < 0.05) systemic blood pressure (systolic and pulse pressure) than the control and NPG groups. Both glaucoma groups had greater levels of fibrinogen (which was of borderline statistical significance) than the control group.

CONCLUSIONS

Elevated levels of <em>prothrombin</em> <em>fragments</em> <em>1</em> + <em>2</em> and D-dimer indicate activation of the coagulation cascade and fibrinolysis pathway, respectively, leading to a hypercoagulable state in untreated POAG. These findings may contribute to the reported increased prevalence of retinal venous thrombosis in glaucoma and also to the pathogenesis of optic nerve damage in glaucoma.

BACKGROUND

Changes in platelet aggregation (PA) and platelet surface receptor expression induced by thrombolytic therapy for acute myocardial infarction may influence the rate of initial reperfusion and early reocclusion.

RESULTS

In the RAPID-<em>1</em> (Reteplase Angiographic Phase II International Dose-finding study), RAPID-<em>2</em> (Reteplase vs Alteplase Patency Investigation During myocardial infarction), INJECT (INternational Joint Efficacy Comparison of Thrombolytics), and GUSTO-3 (Global Use of Strategies To Open occluded coronary arteries) trials, <em>1</em><em>2</em>6 patients were enrolled in a single center. Patients were treated with either conventional alteplase (<em>1</em>00 mg/<em>1</em>80 min; n=<em>1</em>5), accelerated alteplase (<em>1</em>00 mg/90 min; n=<em>2</em><em>1</em>), reteplase <em>1</em>0+<em>1</em>0-U double bolus (n=50), reteplase <em>1</em>0+5-U double bolus (n=<em>1</em>5), reteplase <em>1</em>5-U single bolus (n=<em>1</em>5), or streptokinase (<em>1</em>.5 MU/60 min; n=<em>1</em>0). PA (after stimulation with ADP), P-selectin expression and fibrinogen binding to glycoprotein (GP) IIb/IIIa (determined by flow cytometry with and without stimulation with ADP), and levels of soluble P-selectin, <em>prothrombin</em> <em>fragments</em> F<em>1</em> and F<em>2</em>, thrombin-antithrombin complexes (TAT), and antithrombin III (ATIII) were determined. PA decreased significantly at <em>1</em> and <em>2</em> hours in patients treated by <em>1</em>0+<em>1</em>0-U reteplase or by streptokinase. Fibrinogen binding to platelet GP IIb/IIIa followed a similar pattern. Significant thrombin generation and significantly elevated thrombin levels during thrombolysis were reflected by increased F<em>1</em> and F<em>2</em> <em>fragments</em> and TAT levels in all treatment groups. ATIII levels decreased significantly during thrombolytic therapy.

CONCLUSIONS

A decrease in PA in patients treated by reteplase or streptokinase compared with alteplase could be observed in the early phase. Double bolus (<em>1</em>0+<em>1</em>0 U) reteplase and streptokinase resulted in lower PA at <em>1</em> and <em>2</em> hours than therapy with accelerated alteplase. Total fibrinogen and fibrinogen binding to GP IIb/IIIa tended to be lower during the first <em>2</em> hours after reteplase than after accelerated alteplase.

The activation of serine protease zymogens involves conformational changes that increase the affinity of substrate binding and the activity of the catalytic center. The activation of <em>prothrombin</em> is particularly complex and requires several cleavages in the proenzyme region in addition to the conserved activation cleavage after Arg3<em>2</em>0. To understand how these cleavages lead to the exposure of the thrombin anion-binding exosite, a major macromolecular recognition site, interactions of recombinant human <em>prothrombin</em> derivatives with thrombomodulin, and an exosite-specific antibody were studied by competition binding and immunoprecipitation. By either method, the anion-binding exosite is not functional on prethrombin <em>2</em>, which is cleaved after Arg<em>2</em>7<em>1</em> and lacks <em>fragment</em> <em>1</em>.<em>2</em>, nor on meizothrombin, which is cleaved only after Arg3<em>2</em>0. In contrast, the exosite is fully exposed on meizothrombin des-F<em>1</em>, which is cleaved after both Arg3<em>2</em>0 and Arg<em>1</em>55 and therefore lacks amino-terminal <em>fragment</em> <em>1</em> (F<em>1</em>). Thus, two events are required to create the exosite. First, cleavage after Arg3<em>2</em>0 causes conformational changes that are much more extensive than those accompanying the activation of trypsinogen. Second, removal of amino-terminal F<em>1</em> is necessary, perhaps to relieve steric hindrance. These results indicate that the F<em>1</em> <em>fragment</em> regulates access to the thrombin exosite. The properties of meizothrombin des-F<em>1</em> suggest that this <em>prothrombin</em> derivative could have a biological function.