OBJECTIVE

Activated protein C is a physiologic anticoagulant that is activated by thrombin and upregulated during coronary artery bypass grafting. We studied the balance between thrombin generation and activated protein C levels during coronary artery bypass grafting and hypothesized that protein C activation during reperfusion is associated with hemodynamic recovery or postoperative myocardial damage.

METHODS

One hundred patients undergoing elective on-pump coronary artery bypass grafting were prospectively studied. Activated protein C, protein C, <em>prothrombin</em> <em>fragment</em> F1+<em>2</em> (a marker of thrombin generation), and D-dimer (a marker of fibrinolysis) levels were measured preoperatively and at 7 time points during cardiopulmonary bypass and reperfusion and postoperatively. Hemodynamic parameters were measured serially. Cardiac biomarkers (mass of the Mb fraction of creatine kinase and troponin T) were measured postoperatively.

RESULTS

Reperfusion induced a significant increase in thrombin generation. Activated protein C levels peaked after heparin neutralization, when they increased more than 3-fold. Activated protein C levels correlated with F1+<em>2</em> and D-dimer levels during cardiopulmonary bypass and reperfusion. Even though this correlation peaked during early reperfusion (r = 0.55, P < .001), the ratio of activated protein C to F1+<em>2</em> decreased during surgical intervention and early reperfusion by 70% from the preoperative level, indicating a marked delay in protein C activation in relation to thrombin generation. Patients in the highest quintile of activated protein C levels during this period had a higher postoperative cardiac index (mean, 3.1 vs <em>2</em>.5 L x min(-1) x m(-<em>2</em>); P < .05) and lower systemic vascular resistance (mean, <em>2</em>137 vs <em>2</em>4<em>2</em>9 dyne x s x cm(-5) x m(-<em>2</em>); P < .05). Conversely, levels of preoperative activated protein C and activated protein C measured after heparin neutralization were associated with unfavorable hemodynamic recovery postoperatively. Activated protein C or protein C levels were not associated with increased postoperative cardiac biomarkers.

CONCLUSIONS

Reperfusion caused significant thrombin generation that was followed by activation of protein C. The balance of activated protein C with thrombin is associated dynamically with postoperative hemodynamic recovery.

OBJECTIVE

Catecholamines have anti-inflammatory and anticoagulant properties. Dobutamine is a synthetic catecholamine frequently used in patients with septic myocardial dysfunction. The objective was to determine whether a continuous infusion of dobutamine exerts immunomodulatory effects in healthy volunteers challenged with endotoxin.

METHODS

Prospective, open-label study.

METHODS

Clinical research unit of a university hospital.

METHODS

Sixteen male healthy volunteers.

METHODS

Volunteers received a constant infusion with dobutamine (<em>1</em>0 microg.kg.min, n = 8) or physiologic saline (n = 8). All participants were challenged with a bolus injection of endotoxin prepared from Escherichia coli (4 ng/kg). Dobutamine infusion was commenced <em>1</em> hr before endotoxin challenge and was continued until 3 hrs thereafter.

RESULTS

Dobutamine infusion was associated with an increase in mean arterial blood pressure (peak <em>1</em>22 +/- 5 mm Hg) and heart rate (peak 84 +/- 4 beats/min, both p < .05 vs. saline). Endotoxin injection induced the systemic release of cytokines (tumor necrosis factor-alpha, interleukins-6, -8, and -<em>1</em>0) and secretory phospholipase A2, endothelial cell activation (increase in the plasma levels of soluble E-selectin and von Willebrand factor), activation of coagulation (increased plasma levels of soluble tissue factor, F<em>1</em> + 2 prothrombin fragment, and thrombin-antithrombin complexes), and activation with subsequent inhibition of fibrinolysis (increased plasma concentrations of tissue-type plasminogen activator, plasminogen activator inhibitor type I, and plasmin-alpha2-antiplasmin complexes). None of these responses were influenced by dobutamine.

CONCLUSIONS

Dobutamine, infused in a clinically relevant dose, does not influence inflammatory and coagulant pathways during human endotoxemia.

<em>Prothrombin</em> activation requires the direct interplay of activated platelets and plasma clotting factors. Once formed, thrombin causes profound, irreversible activation of platelets and reinforces the platelet plug via fibrin formation. Delayed or deficient thrombin production increases bleeding risk. Commonly employed coagulation assays, the <em>prothrombin</em> and partial thromboplastin times, use clot formation as a surrogate marker of thrombin generation. These assays routinely utilize platelet-poor plasma and completely miss the effects of platelets. Other markers of thrombin generation, <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>) and thrombin-antithrombin complex, are typically measured after the fact. We report a simple assay, which employs the onset of platelet contractile force (PCF) as a surrogate marker of thrombin generation. PCF generation occurs concomitant with the burst of F<em>1</em> + <em>2</em> release. The time between assay start and PCF onset is termed the thrombin generation time (TGT). TGT is prolonged in clotting factor deficiencies and in the presence of direct and indirect thrombin inhibitors. TGT shortens to normal with clotting factor replacement and shortens with administration of recombinant factor VIIa. TGT is short in thrombophilic states such as coronary artery disease, diabetes and thromboangiitis obliterans and prolongs toward normal with oral and intravenous anticoagulants.

Microparticles (MPs) are blebs released from cellular surfaces during activation/apoptosis. They are procoagulant, pro-inflammatory and could contribute to pathogenesis of deep venous thrombosis (DVT). This study compared the number, cellular origin and procoagulant activity of MPs on DVT patients in different clinical situations: at diagnosis (n = 9, 5F/4M; mean age = 4<em>1</em>.<em>1</em><em>1</em>), <em>1</em>-3 years after warfarin withdrawal (n = <em>1</em>0, 7F/3M; mean age = 3<em>2</em>.90), associated to antiphospholipid syndrome (APS; n = <em>1</em><em>1</em>, 9F/<em>2</em>M; mean age = 33.8<em>2</em>), or asymptomatic carriers of Factor V Leiden (FVL; n = 7, 7F/0M; mean age = 34.00) vs healthy controls (CTR). The quantification and characterization were performed by flow cytometry using CD<em>2</em>35, CD6<em>1</em>, CD45, CD3<em>1</em>, CD<em>1</em>4, CD45, anti-TF and Annexin V. The plasmatic procoagulant activity was investigated by <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>) determination. The MPs procoagulant activity was analyzed by D-dimer (DD<em>2</em>) and Thrombin Generation Test (TGT) on a healthy pool of plasmas adjusted or not by their number (<em>1</em>0,000 MPs). The MPs percentages were not different between the groups, but absolute number was increased in patients <em>1</em>-3 years after warfarin withdrawal vs CTR (P = 0.0<em>2</em>). There was no difference of the MPs cellular origin comparing patients to controls. TGT using <em>1</em>0,000 MPs was lower on these patients (P = 0.0<em>1</em>). APS patients showed a reduction of plasmatic procoagulant activity (P = 0.004), but they were under warfarin therapy. DD<em>2</em> in the presence of MPs, independently of its number, was higher in patients with DVT at diagnosis (P < 0.000<em>1</em>). MPs of patients with spontaneous DVT at diagnosis can promote coagulation activation demonstrated by increased DD<em>2</em>. Even the increased MPs from patients <em>1</em>-3 years after thrombotic episode generated lower amount of thrombin, they can have a protective effect by activation of Protein C anticoagulant pathway.

The aim of this study was to investigate whether abnormalities in the fibrinolytic system and in the naturally occurring anticoagulant proteins could contribute to the thrombotic risk in essential thrombocythemia. Euglobulin lysis time, fibrin plate lysis area, tissue plasminogen activator antigen, and activity and plasminogen activator inhibitor antigen were measured before and after venous occlusion in a group of <em>1</em>6 patients with essential thrombocythemia and in <em>1</em>6 healthy age and sex matched controls. In addition, resting levels of antithrombin III, D-dimer, <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>, and protein C and S were assessed. The results were related to the presence or absence of a thrombotic history. The results demonstrated that the patients had a significantly elevated fibrin plate lysis area and significantly decreased plasminogen activator antigen, both at baseline and after venous occlusion. They also had significantly decreased levels of plasma protein C and total protein S. There was a modest, non-significant elevation in the plasma concentration of D-Dimer and F <em>1</em> + <em>2</em>. Those patients with a history of thrombosis had significantly lower protein C levels compared with individuals without a thrombotic history. We conclude that patients with essential thrombocythemia have evidence of activated fibrinolysis in the resting state and after stimulation. This, and the decreased levels of protein C and total protein S, may be secondary to chronic clinically occult thrombosis occurring in myeloproliferative disorders.

OBJECTIVE

The purpose of this study was to determine whether primary antiphospholipid syndrome pregnancies are associated with endothelial cell activation in the maternal circulation.

METHODS

Markers of endothelial cell activation were measured every 4 weeks during pregnancy in the blood of <em>2</em>3 women with primary antiphospholipid syndrome and <em>1</em>9 control subjects. All women with antiphospholipid syndrome received anticoagulant treatment. Plasma concentrations of plasminogen activator inhibitor type <em>1</em>, tissue plasminogen activator, soluble intercellular adhesion molecule-<em>1</em>, vascular cell adhesion molecule-<em>1</em>, E-selectin, and soluble thrombomodulin were determined by enzyme-linked immunoassay. Concentrations of <em>prothrombin</em> <em>fragments</em> <em>1</em>+<em>2</em> and D-dimers were also determined.

RESULTS

Three antiphospholipid syndrome pregnancies (<em>1</em>3%) were complicated by intrauterine growth restriction and preeclampsia; one antiphospholipid syndrome pregnancy (4%) was complicated by preterm rupture of membranes. Six women with antiphospholipid syndrome (<em>2</em>6%) had thrombotic events. Differences in concentrations of endothelial cell activation markers between antiphospholipid syndrome and control pregnancies were not significant.

CONCLUSIONS

Despite poorer pregnancy outcome, there was no evidence of greater endothelial cell activation in antiphospholipid syndrome pregnancies that were treated.

OBJECTIVE

It has been previously suggested that activation of coagulation and fibrinolysis may sometime occur in patients with unruptured aortic aneurysm. However, the incidence of this complication and the effect of surgical repair are unknown. The objective of our study was to gain further information on this topic.

METHODS

We investigated activation of the hemostatic process in <em>2</em>0 consecutive patients with unruptured abdominal aortic aneurysm. We then evaluated the effect of surgical repair of the vascular abnormalities.

RESULTS

Both before and in the first week after surgery, the large majority of patients showed clear signs of activation of coagulation (increased plasma levels of <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> and fibrin peptide A), and many had low levels of the natural anticoagulant antithrombin III. Platelets were activated in all cases (high levels of plasma beta-thromboglobulin), and signs of platelet consumption (thrombocytopenia and/or increased mean platelet volume) were present in most of them.

CONCLUSIONS

Activation of the hemostatic process occurs in nearly all patients with abdominal aortic aneurysm and could play a role in the hemorrhagic and thrombotic events that can complicate the clinical development of these subjects.

It is believed that thrombotic activity in nephrotic syndrome is due to an imbalance between procoagulant/thrombotic and anticoagulant/antithrombotic factors in plasma. The aim of this study was to investigate the hypercoagulability risk in childhood minimal change disease and to find possible protective mechanisms with respect to hemostasis. Twenty-six children with minimal change disease were enrolled in this study. All patients were evaluated during an attack and on remission. The control group consisted of 33 healthy children. During the attack period, prothrombosis parameters, total lipid, cholesterol, fibrinogen levels and platelet count increased significantly compared to levels in the remission period. This denotes that hyperviscosity increases thrombosis tendency. In the attack period, the significant increase of <em>prothrombin</em> <em>fragments</em> <em>1</em> + <em>2</em> which shows thrombin formation and thrombin-antithrombin complex which causes <em>prothrombin</em> activation, are an indication of increased thrombosis risk. Five patients with lupus anticoagulant present and 7 patients with, activated protein-C resistance ratios carried an increased thrombosis risk. D-dimer level of fibrinolytic factors significantly increased during the attack period. These findings emphasize the existence of thrombotic activity causing the activation of the fibrinolytic system. The significant increase in protein-C activity in these patients represents one of the protective mechanisms against thrombosis. The decrease in tissue plasminogen activator and antiplasmin indicates the protective role of fibrinolytic activity. Consequently, an increase in the protein-C activity is one of the protective mechanisms. The fibrinolytic system also plays an important role in preventing thrombotic activity in these patients.

OBJECTIVE

Acute myocardial infarction (AMI) is associated with increased coagulation which in the presence of unstable atheroma or endothelial damage leads to occlusive coronary vessel thrombosis. AMI is usually characterized by increased levels of catecholamines. It is possible there may be a link between catecholamines and hypercoagulation, but this still remains to be determined. In the current study we sought to verify whether hypercoagulation is associated with hypersympathetic activity in AMI patients, and whether there is a correlation between increased Methoxyhydroxyphenylglycol (MOPEG) levels (a metabolite of catecholamines) and shorter APTT (a marker of hypercoagulation).

RESULTS

Shorter APTT values were detected in the plasma of AMI patients, which had also increased MOPEG levels. A linear correlation between APTT and MOPEG values was observed. High levels of the coagulation marker <em>prothrombin</em> (<em>fragments</em> <em>1</em>+<em>2</em>) were also found.

CONCLUSIONS

Shortened APTT demonstrates hypercoagulation and high MOPEG levels indicate increased catecholamine metabolism. A direct correlation between APTT and MOPEG was found herein, demonstrating a link between catecholamines and the process of coagulation. Catecholamines may interact with the α<em>2</em>-adrenergic receptors located on platelets and convert factor XII to XIIa or through the kallikrein-kinin system, they may activate factor XII. The activation of factor XII initiates the intrinsic coagulation pathway, which is monitored by APTT. It is suggested to control patients with a shortened APTT and increased sympathetic activity with the aim of preventing secondary coagulation and cardiovascular accidents by administering anti-thrombotic and anti-adrenergic agents.

Plasma levels of the <em>prothrombin</em> activation <em>fragment</em> <em>1</em> + <em>2</em> (F <em>1</em> + <em>2</em>) and of thrombin antithrombin III complexes (TAT) were determined in <em>2</em><em>2</em>5 patients with angina pectoris undergoing coronary angiography. Oral anticoagulant therapy was associated with a marked reduction in mean F<em>1</em> + <em>2</em> (0.63 vs <em>1</em>.6<em>2</em> nmol/l, p < 0.000<em>1</em>) and TAT levels (<em>1</em>.65 vs <em>2</em>.<em>2</em>3 micrograms/l, p < 0.000<em>1</em>). Omitting patients on oral anticoagulants, TAT values showed a positive association with patients' age (r = 0.<em>1</em>8; p = 0.0<em>1</em>) and were slightly higher in patients with a history of myocardial infarction than in those without (<em>2</em>.47 vs <em>2</em>.<em>1</em><em>1</em> micrograms/l; p = 0.06). Both F<em>1</em> + <em>2</em> and TAT levels were increased in patients with angiographically verified coronary atherosclerosis as compared to patients with angina and angiographically normal coronaries (F<em>1</em> + <em>2</em>: <em>1</em>.76 vs <em>1</em>.36 nmol/l, TAT: <em>2</em>.35 vs <em>2</em>.00 micrograms/l; p-values after adjusting for age, sex and past history of myocardial infarction 0.06 and 0.<em>1</em><em>1</em> respectively). However, no graded relationship between F<em>1</em> + <em>2</em> or TAT values and severity of atherosclerosis was observed. This study provides suggestive evidence that a procoagulant state exists in patients with angina pectoris and coronary atherosclerosis. Its relevance in predicting coronary ischaemic events needs to be studied prospectively.

OBJECTIVE

To examine pump-prime aprotinin action on coagulation and fibrinolysis in patients undergoing primary coronary revascularization.

METHODS

A prospective randomized study.

METHODS

A university hospital.

METHODS

Forty-three patients were randomly assigned to either group A, <em>2</em>1 patients treated with <em>2</em> x 10(6) kallikrein inhibitor units (KIU) of aprotinin in the cardiopulmonary bypass (CPB) prime, or group B, <em>2</em><em>2</em> patients, untreated.

METHODS

Patients, scheduled for elective coronary surgery, were treated with <em>2</em> x 10(6) KIU of aprotinin in the CPB prime. Markers of coagulation and fibrinolysis were evaluated.

RESULTS

Surgical times, number of reopenings, and allogeneic blood requirements were collected for each patient. Blood samples were obtained before and after surgery for assessing coagulation (prothrombin time [PT], activated partial thromboplastin time [aPTT], ethanol test, factor VII, antithrombin III [AT III], thrombin-antithrombin III complex [TAT], fragment 1.<em>2</em> of prothrombin [F1.<em>2</em>]) and fibrinolysis (fibrin degradation products [FOP], plasmin-antiplasmin complexes [PAP], D-dimers) markers variations. In group A surgical times were faster, there were fewer reopenings (0 v 3), and fewer blood transfusions (1 patient v 4 patients). The two groups did not differ for PT, aPTT, and fibrinogen measurements. Postoperative FDP (measurable in more patients of group B at the end of the operation), PAP, and D-dimers postoperatory levels (less increased in aprotinin group) show the antifibrinolytic properties of the drug. Regarding the coagulation markers, factor VII decreased, whereas TAT and F1.<em>2</em> increased, all to a lesser extent in the aprotinin group compared with the untreated patients, at the end of operation.

CONCLUSIONS

Pump-prime aprotinin minimized, even if not completely inhibited, the activation of coagulation and fibrinolysis during CPB, possibly ensuring a less complicated and safer postoperative recovery. It seemed to allow the maintenance of a correct balance of hemostatic systems, avoiding the risk of thrombotic phenomena.

BACKGROUND

The origin of coagulation and fibrinolysis abnormalities in cancer patients is unknown. The aim of this study was to measure markers of coagulation and fibrinolysis in portal and peripheral blood from patients with and without gastric malignancy.

METHODS

Blood samples were drawn from the portal vein and a peripheral vein in 39 patients undergoing elective gastric surgery, <em>1</em>8 for gastric malignancy and <em>2</em><em>1</em> for benign disorders, and analyzed for <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>), thrombin-anti-thrombin III complex (TAT), fibrinogen and fibrin degradation products (FgDP, FbDP), and fibrinopeptide A (FpA).

CONCLUSIONS

In portal blood, levels of F<em>1</em> + <em>2</em>, TAT, FpA, FgDP, and FbDP did not differ in the two groups. In peripheral blood, levels of FpA and FbDP were higher in cancer patients, but in a multiple regression model malignancy did not contribute significantly to variation in peripheral FpA or FbDP levels. In both groups FpA levels were higher in portal blood than in peripheral blood.

In patients with unstable angina, intravenous heparin reduces thrombin activity but does not influence thrombin generation. Recombinant hirudin, a direct thrombin inhibitor, may be more effective in inhibiting both thrombin generation and activity. We measured the plasma levels of <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (a marker of thrombin generation) and fibrinopeptide A (a marker of thrombin activity) in 67 patients with unstable angina enrolled in the GUSTO (Global Use of Strategies to Open Occluded Coronary Arteries) IIb trial who were receiving either recombinant hirudin (3<em>1</em> patients) or heparin (36 patients). Blood samples were obtained at baseline (before any treatment), after 3 to 5 days of study drug infusion (immediately before discontinuation), and <em>1</em> month later. In the patients receiving recombinant hirudin, the <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> levels measured immediately before drug discontinuation were significantly lower than at baseline (P:=0.00<em>1</em>4), whereas they had not changed in the patients receiving heparin; at this time point, the difference between patients receiving hirudin and those receiving heparin was statistically significant (P:=0.03<em>2</em>). One month later, the <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> levels in both groups were similarly persistently high and did not differ from baseline. Fibrinopeptide A plasma levels at the end of infusion were significantly lower than at baseline in both treatment groups (P:=0. 0005 for hirudin and P:=0.04<em>2</em> for heparin) and remained lower after <em>1</em> month (P:=0.000<em>1</em> for both hirudin and heparin). The fibrinopeptide A plasma levels were not different between patients treated with hirudin versus heparin at baseline, at the end of infusion, and after <em>1</em> month. Thus, in patients with unstable angina, in vivo thrombin generation and activity are reduced during intravenous infusion of recombinant hirudin. However, the inhibition of thrombin generation is not sustained, and after <em>1</em> month, the majority of patients have biochemical signs of increased thrombin generation.

This study attempted to verify the existence of a correlation between fibrinogen, a major cardiovascular risk factor in diabetes, and indexes of thrombin generation and action, <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>), and D-dimer (D-D), in a group of diabetic subjects compared with a matched control group. Forty insulin-dependent diabetes mellitus patients and 30 matched healthy control subjects participated in this study. The subjects were tested for the following parameters: fibrinogen, <em>prothrombin</em> F<em>1</em> + <em>2</em>, D-D, fasting glycemia, and HbA<em>1</em>c. In addition, 5 diabetic subjects who maintained stable fibrinogen plasma levels>> 300 mg/dl for at least 6 months before the study were treated with <em>1</em><em>2</em>,500 U/day subcutaneous heparin for 7 days. Diabetic subjects showed increased levels of fibrinogen, <em>prothrombin</em> F<em>1</em> + <em>2</em>, and D-D plasma levels. Simple linear regression analysis detected a positive correlation between fibrinogen and <em>prothrombin</em> F<em>1</em> + <em>2</em>, D-D, and glycosylated HbA<em>1</em>c. In the five diabetic subjects treated with heparin fibrinogen, <em>prothrombin</em> F<em>1</em> + <em>2</em> and D-D levels decreased at the end of the treatment. All these parameters returned to baseline after 7 days of washout. These data indicate that fibrinogen plasma levels are correlated to parameters of thrombin activation in plasma in diabetic patients and suggest that high fibrinogen plasma levels might be a risk marker for cardiovascular disease in diabetes because it is an expression of an existing thrombophilia.

There is growing evidence that the tissue factor/factor VIIa pathway of coagulation is enhanced during cardiopulmonary bypass. Hitherto, available evidence has suggested that upregulated monocyte bound tissue factor is made available, either in the blood collected from the site of surgery or on circulating cells. However, cellular upregulation is slow, while generation of factor VIIa in blood collected from the pericardial cavity is rapid. We have therefore investigated the possibility of an alternative source of tissue factor, plasma (as opposed to cellular) tissue factor in blood samples taken from the central vein catheter (systemic circulation) and collected from the pericardial cavity during cardiopulmonary bypass. Six patients undergoing first time cardiopulmonary bypass grafting were studied. Tissue factor antigen was found to be rapidly elevated (by <em>1</em>5 min) in the pericardial plasma, approximately 5-fold above systemic levels (p <0.004). Similar elevations were found in markers of coagulation activation, factor VIIa antigen (p = 0.066), <em>prothrombin</em> <em>fragment</em> F(<em>1</em>+<em>2</em>) (p <0.003) and thrombin-antithrombin complex (p <0.03). To explore whether plasma tissue factor was (or had been) functionally active, factor VIIa was measured also with the soluble tissue factor functional assay after removal of heparin. Functional factor VIIa activity fell significantly in the systemic circulation, probably due to the heparin-induced increase (approximately <em>1</em>5-fold) in tissue factor pathway inhibitor (TFPI), but was elevated in pericardial blood compared with that taken from the central line catheter (p <0.006). These results demonstrate that both components of the activation complex for the extrinsic pathway of coagulation are rapidly generated in pericardial blood during bypass.

Tissue injury during hip surgery results in the activation of the haemostatic system. The aim of this study was to detect markers of haemostatic activity, i.e. <em>prothrombin</em> <em>fragment</em> <em>1</em> and <em>2</em> (F<em>1</em>+<em>2</em>), thrombin-antithrombin (TAT) complexes, fibrin degradation products (FbDP), and soluble fibrin monomers (SF), preoperatively, and on days <em>1</em>, 7 and 35 in plasma of patients undergoing total hip arthroplasty. The study was part of a multicentre study in which the patients were randomized to receive a subcutaneous injection of low molecular weight heparin (LMWH, dalteparin, Fragmin) once daily for 5 weeks or placebo following a <em>1</em>-week LMWH treatment (once daily). Bilateral phlebography was performed between days 33 and 35 or before if patients had clinical symptoms of deep vein thrombosis. A lung scan was performed in patients with clinical symptoms of pulmonary embolism. Levels of the markers were significantly increased on day 35 in the patients receiving LMWH for 7 days compared to patients receiving LMWH for 35 days. In patients receiving LMWH for 5 weeks, levels of FbDP and SF were significantly higher during the entire study period, but TAT and F<em>1</em>+<em>2</em> were normalized on day 35. The markers were increased two to five times on the <em>1</em>st postoperative day in patients with diagnosed venous thromboembolism.

OBJECTIVE

The Boston Area Anticoagulation Trial for Atrial Fibrillation (BAATAF) demonstrated that low-intensity warfarin anticoagulation can, with safety, sharply reduce the rate of stroke in patients with nonvalvular atrial fibrillation. The beneficial effect of warfarin was presumably related to a decrease in clot formation in the cardiac atria and subsequent embolization.

METHODS

To assess the effect of warfarin therapy on in vivo clotting in patients in the BAATAF, we measured the plasma level of <em>prothrombin</em> activation <em>fragment</em> F1+<em>2</em>. One sample was obtained from 1<em>2</em>5 patients from the BAATAF; 6<em>2</em> were taking warfarin and 63 were not taking warfarin (control group).

RESULTS

The warfarin group had a 71% lower mean F1+<em>2</em> level than the control group (mean F1+<em>2</em> of 1.57 nmol/L in the control group compared with a mean of 0.46 nmol/L in the warfarin group; P < .001). F1+<em>2</em> levels were higher in older subjects but were consistently lower in the warfarin group at all ages. Fifty-two percent of patients in the control group were taking chronic aspirin therapy at the time their F1+<em>2</em> level was measured. Control patients taking aspirin had F1+<em>2</em> levels very similar to control patients not taking aspirin (mean of 1.5<em>2</em> nmol/L for control patients on aspirin compared with 1.64 nmol/L for control patients off aspirin; P>> .1).

CONCLUSIONS

We conclude that prothrombin activation was significantly suppressed in vivo by warfarin but not aspirin among patients in the BAATAF. These findings correlate with the marked reduction in ischemic stroke noted among patients in the warfarin treatment group observed in the BAATAF.

OBJECTIVE

To investigate whether any changes occur in the coagulative/fibrinolytic cascade in patients with subarachnoid hemorrhage (SAH) or hypertensive intracerebral hemorrhage (HICH).

METHODS

Subjects included <em>1</em>43 patients with intracranial hemorrhage (SAH, n = 50; HICH, n = 8<em>2</em>; ROSC-SAH [return of spontaneous circulation after cardiopulmonary arrest due to SAH], n = <em>1</em><em>1</em>). Coagulative and fibrinolytic factors were measured in blood samples taken on admission.

RESULTS

The <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> level was significantly higher (p < 0.005) in SAH patients than in HICH patients. The fibrinolytic factors (plasmin alpha <em>2</em>-plasmin inhibitor complex, D-dimer, or fibrinogen degradation products) in SAH and ROSC-SAH were both significantly higher than those in HICH, but the significance of difference was stronger in the case of ROSC-SAH (p < 0.05).

CONCLUSIONS

Both coagulative and fibrinolytic activities were altered after the onset of SAH. These results demonstrate that the coagulative/fibrinolytic cascade might be activated via different mechanisms in different types of stroke. It remains unclear, however, whether a significant alteration of the fibrinolytic cascade in patients with ROSC-SAH might be a nonspecific phenomenon attributable to the reperfusion after collapse.

OBJECTIVE

To explore the value of dynamically monitored levels of plasma <em>prothrombin</em> <em>fragment</em>(<em>1</em>+<em>2</em>) (F(<em>1</em>+<em>2</em>)) and D-dimer in the process of thrombolysis with urokinase.

METHODS

Blood samples were collected at baseline and at hours <em>1</em>, <em>2</em>, 3, 6, <em>1</em><em>2</em>, <em>2</em>4, 48, 7<em>2</em>, and 96 after urokinase infusion finished. The levels of plasma F(<em>1</em>+<em>2</em>) and D-dimer of 45 patients who received urokinase intravenous infusion were assayed by ELISA and fluorescent immunoassay, and analysed dynamically with their clinical outcomes.

RESULTS

The levels of plasma F(<em>1</em>+<em>2</em>) and D-dimer in patients before urokinase thrombolysis were significantly higher than age- and gender-matched normal controls (all p<0.05). After urokinase infusion was finished, three kinds of dynamic changes of plasma F(<em>1</em>+<em>2</em>) and D-dimer with different clinical outcomes appeared. In effective subgroup (n=30), the plasma D-dimer increased quickly and reached to the peak at the third hour, remained at the higher level for more than <em>2</em>4 hours, and then decreased gradually; while plasma F(<em>1</em>+<em>2</em>) began to decrease at the second hour and promptly approached to its trough near the baseline, after <em>2</em>4 hours. In non-effective subgroup, the D-dimer was slightly higher than its baseline and much lower than that in the effective subgroup, and the most high level appeared at the sixth hour and decreased quickly; moreover, the peak of F(<em>1</em>+<em>2</em>) appeared at the third hour and remained at high level for more than 40 hours, and then decreased to the trough which was near the baseline. In cerebral hemorrhage subgroup, the D-dimer peak (<em>2</em>55<em>1</em> +/- 68 microg/l) appeared at the third hour, which was <em>1</em>.5-fold higher than that in effective subgroup (<em>1</em>895 +/- 89 microg/l), 5.0-fold higher than that in non-effective subgroup (53<em>1</em> +/- 46 microg/l), and 6.0-fold higher than its baseline, and kept higher level for more than 7<em>2</em> hours; meanwhile, the F(<em>1</em>+<em>2</em>) decreased remarkably and reached the trough which was far below its baseline.

CONCLUSIONS

Plasma F(<em>1</em>+<em>2</em>) and D-dimer levels are closely related to the different clinical outcomes after urokinase thrombolysis. Thrombotic-fibrinolytic imbalance might be one of the main reasons which affected the prognosis of ischemia stroke. Dynamic assay of the two biomarkers in plasma besides clinical observation might be helpful to predict the early prognosis of acute ischemia stroke during the process of urokinase thrombolysis.

The physiology of the hemostatic system in infancy and childhood is different from that in adulthood. Despite differences in several components of the coagulation and fibrinolytic systems, there is no evidence that children are at greater risk for hemorrhagic or thrombotic problems compared with adults (<em>1</em>,<em>2</em>). Advances in understanding of the biochemistry of the hemostatic mechanism have led to the development of sensitive immunochemical methods for measuring peptides or enzyme-inhibitor complexes that are liberated with the activation of the coagulation and fibrinolytic systems in vivo (3). Activation markers of coagulation and fibrinolysis have been measured in newborns, infants and children with a variety of underlying disorders (4-<em>1</em>6). However, reference ranges for children of different age groups have hitherto not been established. The aim of the present study was to document thrombin-antithrombin III-complex (TAT), <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>), plasmin-alpha <em>2</em>-antiplasmin-complex (PAP) and D-dimer in healthy children and to determine whether age-related differences can be demonstrated.

BACKGROUND

French lyophilized plasma (FLyP) is used routinely by the French Armed Forces in war settings. The authors compared concentrations of coagulation proteins and global in vitro hemostatic properties in FLyP and in the same plasma before lyophilization to assess the impact of lyophilization on coagulation properties.

METHODS

Twenty-four batches of plasma before and after lyophilization were tested for coagulation proteins. Thrombin generation time, thrombin antithrombin concentration, <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>, and thromboelastography were assessed. Finally, the efficiencies of FLyP and plasma before lyophilization were compared on a hemorrhagic shock hemodilution model and tested on TEG(Haemoscope Corporation, Glenview, IL).

RESULTS

Prothrombin time ratio (<em>1</em>.<em>1</em> ± 0.<em>1</em> vs. <em>1</em>.<em>2</em> ± 0.<em>1</em>) and activated partial thromboplastin time (35 ± <em>1</em>.3 vs. 39 ± <em>2</em>.4 s) were significantly increased in FLyP (8 ± 3%, P < 0.05 and <em>1</em><em>1</em> ± 5%, P < 0.00<em>1</em>, respectively). Activity of factors V (85 ± <em>1</em>8 vs. 5<em>1</em> ± <em>1</em>6 UI/ml) and VIII (0.77 ± 0.<em>1</em><em>1</em> vs. 0.6<em>2</em> ± 0.<em>1</em>0 UI/ml) was also diminished (<em>2</em>5 ± <em>1</em><em>2</em>% and <em>2</em>0 ± 7%, respectively); however, activity of other factors was preserved. The authors observed no alteration in the thromboelastographic parameters. Thrombin generation was preserved when induced with 5 pM tissue factor in vitro but significantly reduced when using <em>1</em> pM tissue factor. The thrombin-antithrombin complex and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> attested for the absence of coagulation activation. This hemodilution model showed no significant difference before and after lyophilization.

CONCLUSIONS

The study results account for a significant decrease of factors V and VIII in FLyP. However, the global capacity to induce clot formation in vitro seems to be preserved. The clinical relevance of these decreased factors is not known.

OBJECTIVE

Systemic thromboembolism is a major complication in patients with mitral stenosis (MS), especially in those who have atrial fibrillation (AF). It has been suggested that systemic coagulation activity may be increased in these patients. The study aim was to investigate the relationship between control of ventricular rate and systemic coagulation factors in patients with MS and AF by measuring plasma levels of <em>prothrombin</em> <em>fragment</em> (PF) <em>1</em>+<em>2</em>, thrombin-antithrombin III complex (TAT) and plasminogen activator inhibitor-<em>1</em>.

METHODS

Fifty-four consecutive patients with moderate to severe MS and AF were included in the study. Patients with resting heart rates < <em>1</em>00 beats per min were considered as having a controlled ventricular response rate (group A; n = <em>2</em>8) and those with>> <em>1</em>00 beats per min as an uncontrolled ventricular response rate (group B; n = <em>2</em>6).

RESULTS

Group A patients had a lower mean mitral gradient and pulmonary artery pressure than group B patients (<em>1</em><em>1</em> +/- 6 versus <em>1</em>5 +/- 5 and 35 +/- 7 versus 39 +/- 8; p < 0.05, respectively). Plasma concentrations of PF <em>1</em>+<em>2</em> (4.<em>1</em>7 +/- <em>2</em>.<em>1</em> versus <em>2</em>.95 +/- <em>1</em>.<em>2</em><em>1</em>; p < 0.0<em>1</em>) and TAT III (4.6<em>1</em> +/- <em>1</em>.75 versus 3.<em>1</em><em>2</em> +/- <em>1</em>.0<em>1</em>; p < 0.0<em>1</em>) were elevated in group B compared with group A. Similarly, group B patients had higher plasminogen activator inhibitor-<em>1</em> levels than group A patients (7.87 +/- 3.8 versus 5.8 +/- <em>2</em>.9; p < 0.05). A significant correlation was found between heart rate and plasma PF <em>1</em>+<em>2</em> and TAT levels. Multiple logistic regression analysis revealed that heart rate and mean mitral gradient were independent predictors of systemic coagulation activation.

CONCLUSIONS

Besides contributing towards hemodynamic and symptomatic relief, the control of AF rate in MS patients induces a drastic decline in coagulation activation, and may also reduce the incidence of thromboembolism.

Platelets and leucocytes are important effector cells of the haemostatic and inflammatory responses to tissue injury. To investigate the effects of surgical trauma on platelet activation (assessed by measuring levels of P-selectin and beta-thromboglobulin), leucocyte activation (CD<em>1</em><em>1</em>b expression) and leucocyte-platelet interactions (leucocyte-platelet complexes), 30 patients undergoing primary hip arthroplasty were studied before and at the end of surgery, and on days <em>1</em> and <em>1</em>0 post-operatively, using a whole-blood flow cytometry assay. The inflammatory response was followed by measurement of the levels of C-reactive protein and interleukin-6 in plasma, and the activation of coagulation was monitored by determination of <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> levels. On day <em>1</em> post-operatively a significantly increased expression of CD<em>1</em><em>1</em>b on monocytes was noted, but no direct correlation was found between monocyte activation and interleukin-6 production or C-reactive protein at this time point. The percentage of monocyte-platelet and neutrophil-platelet complexes was markedly increased on day <em>1</em>0 post-operatively compared with pre-operative levels, and levels of these complexes were significantly positively correlated with beta-thromboglobulin levels. Activation of coagulation (<em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>) on day <em>1</em>0 post-operatively was positively correlated with the extent of surgical trauma (duration of surgery, amount of blood loss) and with the increase in platelet activation (beta-thromboglobulin). In conclusion, hip arthroplasty induces platelet and coagulation activation, and also an inflammatory response that is maintained for more than <em>1</em>0 days post-operatively. This indicates an interaction between the immune and the haemostatic systems in the post-operative phase after hip arthroplasty.

Increased age is associated with a higher risk of thrombotic events. The aim of this study was to investigate the age-related changes in hemostasis before and after moderate exercise controlled by individual anaerobic threshold as recommended for rehabilitation training. In this study, <em>2</em>4 young (<em>2</em>5 +/- <em>1</em> years) and <em>2</em>4 middle-aged healthy nonsmokers (48 +/- <em>1</em> years) underwent an individualized exercise test with 80% of individual anaerobic threshold (young individuals: <em>1</em><em>2</em>7 +/- 6 W; middle-aged individuals: <em>1</em><em>2</em>8 +/- 5 W; values are expressed as mean +/- standard error of mean) for 60 minutes. The blood samples were collected before and after the exercise. The age-related higher (P < or = .05) levels could be detected in factors II, VII, VIII, IX, XI, XII, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, in tissue plasminogen activator antigen and activity, as well as in plasminogen. The relative exercise-induced increases in these parameters were similar in both groups, although beginning at a higher level for those in the middle-aged group.A statistically enhanced increase after exercise in the middle-aged group could be shown in <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (young individuals: 98 +/- 6 to <em>1</em>0<em>2</em> +/- 6 pmol/L; middle-aged individuals: <em>1</em>38 +/- 7 to <em>1</em>56 +/- 8 pmol/L) and in thrombin-antithrombin complex (young individuals: <em>2</em>.<em>2</em> +/- 0.<em>1</em> to 3.<em>1</em> +/- 0.<em>2</em> microg/L; middle-aged individuals: <em>2</em>.4 +/- 0.3 to 3.9 +/- 0.6 microg/L); the latter only showing a tendency. The data show the age-related changes with a rise in blood coagulation and fibrinolysis in a healthy middle-aged group compared with younger participants. Moderate exercise leads to comparably relative increases in hemostatic parameters but starting at higher levels. However, the exercise-induced thrombin generation (<em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>) is enhanced in the middle-aged participants in comparison with younger participants, but may be compensated by a sufficient fibrinolysis, and therefore the hemostatic system remains in balance.