Activation of coagulation in amniotic fluid during normal human pregnancy

Introduction

Amniotic fluid (AF) is an important medium for fetal development which exhibits high procoagulant activities; however, the role of these procoagulants during pregnancy has not been elucidated and might be associated with pregnancy complications. The current study aimed to evaluate factor X (FX) activation and its association with tissue factor (TF), tissue factor pathway inhibitor (TFPI) and coagulation activation markers in AF during normal human pregnancy.

Methods

Activation of FX and concentration of TF, free TFPI, D-dimer and prothrombin fragments (F1 + 2) were evaluated in AF samples obtained for chromosome analysis from 91 women with normal pregnancy: 65 samples were taken from patients at 16-20 weeks of gestation, 9 samples were drawn at 21-30 weeks and 17 samples−after 30 weeks of gestation.

Results

Activation of FX in AF significantly increased during normal pregnancy (from 65 ± 41 to 205 ± 80 equivalent RVV ng/mg total protein, P < 0.0001). TF and TFPI levels in AF also rose with gestational age. In contrast, the AF concentration of D-dimer and F1 + 2, markers of coagulation activation significantly decreased when expressed per mg total protein. Levels of free TFPI correlated with TF (r = 0.5, P < 0.001), and were 8-fold higher than those of TF during pregnancy.

Conclusion

High levels of TFPI might be associated with the inhibition of procoagulant activity in amniotic fluid during normal pregnancy, which may account for the rarity of clinical amniotic fluid embolism.     

Different effects of enoxaparin and unfractionated heparin on some thrombogenesis markers during hemodialysis: a cross-over study

Background

Unfractionated heparin (UFH) and low molecular weight heparin constitute fundamental anticoagulants during hemodialysis (HD). We aimed to investigate the effect of UFH and enoxaparin on plasma levels of prothrombin fragment 1 + 2 (PF 1 + 2) and thrombin/antithrombin complex (TAT) as markers of intravascular thrombogenesis during HD.

Methods

We enrolled 22 chronic HD patients, who were randomly assigned to either iv enoxaparin (n = 11) or UFH (n = 11) anticoagulation, and followed prospectively for 12 weeks before crossing over to the alternate therapy for further 12 weeks. Plasma levels of PF 1 + 2 and TAT were measured by immunoassay at the start, at 10 and 180 min of HD session after each period of evaluation.

Results

The baseline PF 1 + 2 and TAT levels were comparable under enoxaparin and UFH treatment. PF 1 + 2 significantly decreased during both UFH (χ² ANOVA = 9.82, P = 0.007) and enoxaparin (χ² ANOVA = 29.40, P < 10^− 6) anticoagulated HD, while over-HD TAT levels changes differed depending on the type of heparin. The switch from enoxaparin to UFH treatment was connected with a significantly higher PF 1 + 2 after 10 and 180 min as well as higher TAT concentration after 180 min of HD. Only during enoxaparin anticoagulated HD 34% PF 1 + 2 decrease and TAT levels after 180 min of HD was closely associated with heparin dosage.

Conclusion

Single bolus of enoxaparin ensures efficient and convenient anti-thrombotic protection during HD procedure. Enoxaparin mean dose of 0.67 mg/kg, which is generally lower than manufacturer's instructions, can be recommended for over-dialytic regular use.     

Circulating platelet-derived microparticles and endothelium-derived microparticles may be a potential cause of microthrombosis in patients with osteonecrosis of the femoral head

Introduction

To test the hypothesis that the platelet microparticle (PMP) and endothelial microparticle (EMP) may contribute to the hypercoagulability associated with microvascular thrombosis in patients with nontraumatc osteonecrosis of the femoral head (ONFH).

Materials and methods

The study comprised 46 patients who had been diagnosed with ONFH and 20 control subjects. The plasma was ultracentrifuged, and then PMPs and EMPs were examined by the flow cytometry. The thrombotic and fibrinolytic disorders were investigated.

Results

The numbers of PMPs expressing P-selectin and CD42a and EMPs expressing E-selectin and CD31 in the ONFH patients were significantly higher than those in the controls (P < 0.001). The number of MPs was correlated with the level of the serum C-reactive protein (CRP) (r = 0.661, P < 0.001), but there was a poor correlation between the MPs counts and the risk factors for ONFH (P > 0.05). The mean levels PAI-1, F1 + 2, and TAT were higher in the patients with ONFH than in the controls (P < 0.05).

Conclusions

The elevated numbers of PMPs and EMPs may contribute to hypercoagulability in the ONFH patients. This may provide important pathophysiological insights into the hypercoagulability associated with nontraumatic ONFH and have implications for pharmacological prevention and treatment of ONFH.     

Tissue factor-induced Thrombin Generation in the Fasting and Postprandial State among Elderly Survivors of Myocardial Infarction

Introduction

Tissue factor (TF)-induced thrombin generation (TG) ex vivo has been suggested to be an important method to assess thrombotic risk. No studies have investigated the impact of postprandial lipemia on TF-induced TG. Since myocardial infarction (MI) is associated with elevated postprandial levels of triglycerides, we hypothesized a differential impact of postprandial lipemia on coagulation activation in MI-patients and healthy controls.

Material and Methods

Elderly survivors of acute MI (n = 44) and healthy age-and sex matched controls (n = 43) underwent a fat tolerance test (1 gram per kg body weight) to assess coagulation activation during postprandial lipemia.

Results

The incremental area under the curve (AUCi) for serum triglycerides was higher in MI-patients than in healthy age-and sex matched controls (5.64 ± 0.52 mmol/L?h and 3.94 ± 0.39 mmol/L?h, p = 0.012) during the postprandial phase. Subsequent endogenous activation of coagulation, assessed by FVIIa and thrombin generation (F1 + 2), was similar among groups and not related to levels of triglycerides during the postprandial phase. Healthy individuals had a gradual decline in TF-induced thrombin generation ex vivo, assessed by endogenous thrombin potential (ETP) (AUCi = - 542.4 ± 71.4 nM?min?h, p < 0.001), whereas MI-patients retained their ETP (AUCi = 127.4 ± 89.0 nM?min?h, p = 0.47) in plasma during the postprandial phase (p for group difference = 0.005).

Conclusions

MI-patients had elevated postprandial lipemia and retained their ability for TF-induced TG in plasma ex vivo in the postprandial phase, whereas the capacity gradually decreased in healthy individuals. Further studies are warranted to reveal underlying mechanism(s) and clinical implications.     

Hypercoagulability in chronic kidney disease is associated with coagulation activation but not endothelial function

Introduction

Patients with chronic kidney disease exhibit features of a hypercoagulable state and have endothelial dysfunction, which may contribute to their increased cardiovascular risk. We examined the relationship between coagulation activation and vascular function in patients with chronic kidney disease.

Materials and Methods

We measured parameters of the tissue factor pathway of blood coagulation (tissue factor, factor VIIc and factor X); natural inhibitors (tissue factor pathway inhibitor, protein C, free and total protein S, antithrombin III) and markers of coagulation activation (thrombin-antithrombin complexes, prothrombin fragment 1 + 2) in 66 stage 4&5 chronic kidney disease patients and 36 healthy controls. Their relationship with markers of vascular function (flow mediated dilatation, soluble E-selectin and thrombomodulin) and a mediator of inflammation (interleukin-6) was determined.

Results

Up-regulation of the tissue factor pathway (increased tissue factor and factor VIIc), increased prothrombin fragment 1 + 2 and significant reductions in antithrombin III and the ratio of free protein S: total protein S were found in patients compared to healthy controls. Increased tissue factor antigen was significantly and independently correlated with creatinine and interleukin-6 (P < 0.001). Factor X and antithrombin III were both reduced in chronic kidney disease and correlated (r = 0.58; P < 0.001). Changes in coagulation and anti-coagulation were independent of all measures of endothelial function.

Conclusions

Significant activation of the TF pathway of coagulation and depletion or reduction of some natural anticoagulants in chronic kidney disease was correlated with the degree of renal dysfunction, but not correlated with the abnormalities of vascular function. These data are consistent with a hypercoagulable state in chronic kidney disease that may be independent of endothelial based regulation but associated with an inflammatory state.     

Stent implantation in the superficial femoral artery: Short thrombelastometry-derived coagulation times identify patients with late in-stent restenosis

Introduction

The mechanisms of restenosis, the recurrence of luminal narrowing, are complex and incompletely understood to date. Thrombin, the pivotal enzyme in haemostasis, presumably contributes to the formation of in-stent restenosis (ISR). It was therefore the aim of our study to investigate whether blood coagulation/thrombin generation plays a critical role in the formation of ISR in peripheral artery disease patients with stent angioplasty in the superficial femoral artery.

Materials and Methods

We aimed to examine in this retrospective study whether patients with high-degree restenosis (50-75% lumen diameter reduction, n = 20) are in a hypercoaguable state implying enhanced readiness to generate thrombin compared to patients with low-degree restenosis (< 50% lumen diameter reduction, n = 14).

Results

The coagulation tests calibrated automated thrombography, activated partial thromboplastin time, platelet aggregation, platelet adhesion, fibrinogen, and microparticles’ procoagulant activity did not indicate a different coagulation status in the two patient groups. However, the thrombelastometry-derived value Coagulation Time (CT) was significantly shorter in the high-degree restenosis group (p = 0.012), indicating a hypercoagulable state of patients with high-degree restenosis. Under our experimental conditions, CTs shorter than 444.5 s identify patients at high risk (sensitivity = 95%) for luminal narrowing.

Conclusions

Our study supports the assumption that blood coagulation/thrombin generation plays a critical role in the development of ISR in peripheral arteries after stent insertion and that the thrombelastometry-derived CT might be a suitable value to identify peripheral artery disease patients at risk for development of high-degree in-stent restenosis in the superficial femoral artery.     

Chronic oral anticoagulant therapy in carotid artery stenting: the un-necessity of perioperative bridging heparin therapy

Introduction

Chronic oral anticoagulant therapy (OAT) is of widespread use, and usually its management in patients undergoing carotid artery stenting (CAS) is through perioperative bridging heparin therapy. Aim of the present study is to analyze a single center experience of CAS in patients maintaining OAT without perioperative bridging heparin therapy.

Materials and methods

A retrospective evaluation of consecutive patients submitted to CAS was performed. Clinical anatomical characteristics and chronic OAT were evaluated to find a correlation with stroke, death, myocardial infarction and bleeding from the access site by Chi-square, Fisher's tests and regression analysis.

Results

502 CAS were performed in a 5-year period. Twelve (2.4%) strokes, 1 (0.2%) death, no myocardial infarctions and 4 (0.8%) access site bleeding occurred in the perioperative period. In the overall population the presence of type 3 or bovine aortic arch was associated with stroke (5.5% vs. 1.5% p = 0.02), and preoperative neurological ischemic symptoms were correlated with higher incidence of the composite event of stroke/death (4.8% vs. 1.4%, p = 0.05). Twenty patients (4.0%) under chronic OAT were submitted to CAS without perioperative bridging heparin therapy with no complications. Overall, patients under OAT had no significantly different outcome compared with patients without OAT.

Conclusions

OAT without perioperative bridging heparin therapy is safe and effective. This data could be useful in the management of patients with chronic OAT submitted to CAS.     

Haemostatic system, biochemical profiles, kynurenines and the prevalence of cardiovascular disease in peritoneally dialyzed patients

Introduction

The haemostatic and biochemical abnormalities participate in the progression of cardiovascular disease (CVD) in peritoneally dialysed (PD) patients. Recently, the role of kynurenine (KYN) pathway of tryptophan (TRP) degradation in the development of CVD has been postulated.

Materials and methods

The present study was undertaken to investigate haemostatic parameters, biochemical profiles and kynurenines in PD patients both with and without CVD compared to age- and sex-matched healthy controls.

Results

The multiple biochemical abnormalities were present in PD patients, particularly in those with CVD. Tissue factor (TF), its inhibitor (TFPI), prothrombin fragment 1 + 2 (F_1 + 2)_, urokinase-type plasminogen activator (uPA), its soluble receptor (suPAR), plasmin/antiplasmin (PAP) complexes, KYN, kynurenic (KYNA) and quinolinic (QA) acids levels were significantly higher, whereas TRP was significantly lower in the PD patients than in the controls. Tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) were higher in the patients with CVD than in the patients without CVD and controls. PD patients with CVD had higher F_1 + 2, and they had lower suPAR and KYNA levels compared with PD patients without CVD. KYNA was positively associated with TFPI, whereas its was inversely associated with F_1 + 2 both in the whole PD group and in CVD patients. Logistic regression analysis showed that low KYNA, high glucose, low HDL-cholesterol levels and the duration of dialysis treatment were independently associated with the presence of CVD in PD patients.

Conclusions

The present study suggests a relationship between kynurenine pathway of tryptophan degradation, haemostatic and biochemical disturbances and CVD prevalence in peritoneally dialyzed patients.     

Fibrin clot properties in women heterozygous for factor V Leiden mutation: Effects of oral contraceptives

Introduction

Oral contraceptives (OC) in the presence of factor V Leiden mutation (FVL) markedly increase the risk of venous thromboembolism (VTE). Little is known about the OC and FVL-related alterations in fibrin clot properties.

Subjects and Methods

Plasma fibrin clot permeability (K_s) and efficiency of lysis, reflected by clot lysis time (CLT) and the rate of D-dimer release from clots (D-D_rate) induced by recombinant tissue plasminogen activator (tPA) were determined in 25 women with a family history of VTE who were heterozygous for FVL [FVL(+/−) - twice, on third-generation OC and after their discontinuation. Female non-carriers of FVL, matched for demographics, using OC and after their discontinuation served as controls (n = 25). All participants had no personal history of VTE.

Results

OC discontinuation in FVL(+/−) women resulted in shortened CLT (− 9%), and increased K_s (+ 4%) and D-D_rate (+ 1.4%; all p < 0.01). Alterations in fibrin clot properties were associated with decreased prothrombin fragments 1 + 2 (F1 + 2) (− 8%), plasminogen activator inhibitor-1 (PAI-1) antigen (− 11%), and thrombin activatable fibrinolysis inhibitor (TAFI) activity (− 20%; all p < 0.01). During OC use FVL(+/−) carriers compared with non-carriers had higher platelet count, activity of PAI-1, TAFI, and tPA, as well as prolonged CLT and higher D-D_max, along with lower D-D_rate and K_s. Multiple regression analysis adjusted for fibrinogen and age, showed that PAI-1 antigen and TAFI activity independently predicted CLT in FVL(+/−) women on OC.

Conclusion

FVL(+/−) is associated with hypofibrinolysis in apparently healthy women and third-generation OC administration unfavorably alters plasma clot characteristics in female FVL(+/−) carriers with a family history of thrombotic events.     

The plasma levels of activated thrombin activatable fibrinolysis inhibitor and thrombomodulin in Behçet Disease and their association with thrombosis

Objective

To investigate the plasma levels of activated thrombin activatable fibrinolysis inhibitor (aTAFI) and thrombomodulin (TM) in Behçet disease (BD) and their relationship with thrombosis.

Methods

Plasma aTAFI and TM levels were measured by ELISA in 89 patients with BD (18 having venous thrombosis) and in 86 healthy controls.

Results

Compared with healthy controls, the BD group had significantly lower levels of aTAFI (13.49 ± 8.88 µg/ml vs. 26.76 ± 11.57 µg/ml, p < 0.0001) and significantly higher levels of TM (3.26 ± 1.85 ng/ml vs. 2.6 ± 0.69 ng/ml, p = 0.0003). Neither aTAFI, nor TM levels differed significantly between BD patients with and without thrombosis (p > 0.05). Despite a tendency to positive correlation (r = 0.37, p = 0.0004) between plasma levels of aTAFI and TM in healthy controls, there was a tendency for negative correlation (r = -0.51, p < 0.0001) between these two parameters in BD patients.

Conclusion

The plasma aTAFI and TM levels do not seem to be related with the presence of thrombosis observed in BD. Increased plasma TM levels in BD may simply reflect endothelial cell activation and dysfunction.     

Postprandial changes in the phospholipid composition of circulating microparticles are not associated with coagulation activation

Introduction

Evidence is present that the phospholipid composition of circulating cell-derived microparticles (MP) affects coagulation in vivo, and that postprandial metabolic alterations may be associated with hypercoagulable state. Our objective was to investigate whether postprandial metabolic responses affect the phospholipid composition of MP, and whether such changes are associated with coagulation activation.

Materials and Methods

Twelve healthy males were studied twice and randomly received two consecutive meals or remained fasted. Blood was collected before and at 2, 4, 6 and 8 h following breakfast. Plasma concentrations of prothrombin-F_1 + 2 and thrombin-antithrombin-complexes were measured. Numbers and cellular origin of MP were determined by flowcytometry. The phospholipid composition of MP was determined by hpTLC. In vitro procoagulant activity of MP was studied by fibrin generation.

Results

During the meal visit, plasma glucose, triglyceride and insulin levels increased, compared to baseline and the fasting visit (all P < 0.05). Postprandially, the total numbers of MP increased in time compared to the fasting visit (P < 0.05). Erythrocyte-derived MP increased (6-fold) during the meal visit, but remained constant on the fasting day (P < 0.001). On the meal versus fasting day circulating MP contained increased phosphatidylcholine (P < 0.05) and decreased sphingomyelin (P < 0.05) amounts. The amount of phosphatidylserine did not change. Concentrations of plasma F_1 + 2 and thrombin-antithrombin were similar on both days, as was the ability of MP to generate fibrin in vitro.

Conclusion

Although numbers, cellular origin and phospholipid composition of MP alter during exposure to two consecutive meals in healthy subjects, this does not lead to changes in the coagulation activation in vivo.     

Is the surgical repair of unruptured atherosclerotic aneurysms at a higher risk of intraoperative ischemia?

Background

The incidence of ischemia might be increased in the surgical repair of atherosclerotic unruptured aneurysms compared to non-atherosclerotic aneurysms. The atherosclerotic wall might increase the occurrence of thrombembolic events or its rigidity might endanger the occlusion of perforators within the aneurysm vicinity.

Methods

87 patients (53 patients without and 34 patients with atherosclerotic unruptured aneurysms, 50.5 ± 9.7 years) were analyzed for severity of atherosclerosis within the aneurysm and the aneurysm bearing vessel, surgical maneuvers, intraoperative alterations in evoked potentials and clinical and neuroradiological results.

Results

Temporary vessel occlusion (25% vs. 50%, p = 0.021), repositioning of a permanent clip (21% vs. 56%, p = 0.001) and aneurysm remnants (2% vs. 18%, p = 0.012) occurred more often in patients with atherosclerotic aneurysms. At 6 months, 3/34 patients with atherosclerosis (8.8%) had an unfavorable outcome, all patients without atherosclerosis had a favorable outcome (p = 0.056).

Conclusion

The surgical repair of unruptured aneurysms is safe but patients with atherosclerotic altered vessels and aneurysms accounted to a minor increase in unfavorable outcome and an increased risk of morbidity at 6 months postoperatively. This factor should be taken into consideration when performing surgery of atherosclerotic, unruptured aneurysms.     

Comparison of a direct Factor Xa inhibitor, edoxaban, with dalteparin and ximelagatran: A randomised controlled trial in healthy elderly adults

Introduction

Edoxaban (the free base of DU-176b) is a new, oral direct Factor Xa inhibitor. This is the first study to compare the hemostatic response to edoxaban, ximelagatran, and dalteparin in healthy, elderly adults.

Materials and Methods

In this open-label, active-controlled clinical trial, 40 adults (65-75 years), were randomised to: oral edoxaban (60 mg, twice-daily, 7 doses), subcutaneous dalteparin (5000 IU, once-daily, 4 doses), oral ximelagatran (24 mg, twice-daily, 7 doses) or no drug. Blood samples were taken before, and 1.5, 4, 12, 24, 72, 84, 96, 108, 120, and 144 hours after, the first dose. The primary outcomes were changes in thrombin-antithrombin complex, prothrombin fragment 1 + 2 and D-dimer, and adverse events. Additional biomarkers of coagulation, and endothelial cell and platelet activation were compared (ANOVA).

Results

All subjects completed the study. Inhibition of thrombin generation lag time, peak, and constant velocity index were significantly greater, and extended for a longer period of time, following edoxaban administration, compared with dalteparin. We found that the traditional assay for anti-FXa activity was not appropriate for the new anticoagulants. Biomarker changes following edoxaban administration (including prolongation of prothrombin time) reflected inhibition of Factor Xa; there was no effect on platelet, tissue factor or endothelial activation. There were no clinically significant changes in primary outcomes. No serious adverse events were reported.

Conclusion

Oral administration of edoxaban resulted in effective Factor Xa and TG inhibition, and was well-tolerated. Studies are needed to confirm edoxaban (60 mg daily) use in clinical practice.

Sponsorship

Daiichi Sankyo Pharma Development.     

Prothrombin fragment 1 + 2 in urine as a marker on coagulation activity in patients with suspected pulmonary embolism

Introduction

We have recently reported that increased levels of urine prothrombin fragment 1 + 2 reflected radiologically verified deep vein thrombosis. In this study we evaluated whether urine prothrombin fragment 1 + 2 was associated with pulmonary embolism in non-selected patients.

Materials and methods

Patients with clinical suspected pulmonary embolism were interviewed on comorbidities and medications. Urine was collected from each patient before radiological examination and snap frozen until analysed on urine prothrombin fragment 1 + 2 with an ELISA kit. Imaging of the pulmonary arteries were conducted with contrast enhanced computer tomography.

Results

Pulmonary embolism was diagnosed in 44/197 patients. Non-significantly higher urine prothrombin fragment 1 + 2 levels were found in non-selected patients with pulmonary embolism vs. those without (p = 0.324). Significantly higher urine prothrombin fragment 1 + 2 levels were found in the pulmonary embolism positive patients without comorbidities (n = 13) compared to the control group (n = 28) (p = 0.009). The calculated sensitivity, specificity and negative predictive value using the lowest detectable urine prothrombin fragment 1 + 2 level was 82%, 34% and 87%, respectively.

Conclusions

There was no significant urine prothrombin fragment 1 + 2 level difference in patients with and without pulmonary embolism. In non-comorbide pulmonary embolism positive patients the urine prothrombin fragment 1 + 2 levels were significantly higher compared to the control group. The negative predictive value found in this study indicates that uF1 + 2 has the potential to identify patients with a low risk of PE.     

Influence of renal function and platelet turnover on the antiplatelet effect of aspirin

Introduction

Kidney disease predisposes to cardiovascular events. This study investigated the influence of renal function and platelet turnover on the antiplatelet effect of aspirin in patients with coronary artery disease.

Materials and Methods

We included 124 aspirin-treated patients with coronary artery disease and normal to moderately reduced renal function. All tests were performed one hour after aspirin ingestion. Renal function was assessed using creatinine, estimated glomerular filtration rate (eGFR), and cystatin C. The antiplatelet effect of aspirin was evaluated using the VerifyNow® Aspirin assay and multiple electrode aggregometry (MEA, Multiplate®) induced by collagen (1.0 μg/mL) and arachidonic acid (1.0 mmol/L). Von Willebrand factor was measured as a marker of endothelial dysfunction. Platelet turnover was evaluated by measurements of immature, reticulated platelets.

Results

Renal function did not influence the antiplatelet effect of aspirin evaluated by MEA (r = − 0.2-0.09, p = 0.03-0.77) or the VerifyNow® (r = − 0.12-0.11, all p-values > 0.1). In contrast, renal function correlated inversely with von Willebrand factor levels (r_creatinine = 0.48, p < 0.0001; r_eGFR = − 0.46, p < 0.001; r_{cystatin C} = 0.54, p < 0.0001). The number of immature platelets correlated with platelet aggregation according to MEA (r = 0.20-0.39, all p-values < 0.03), but not according to VerifyNow® (r = − 0.07, p = 0.50).

Conclusions

A reduced antiplatelet effect of aspirin may be explained by an increased number of immature platelets. Moderately impaired renal function was associated with high levels of von Willebrand factor, but not with a reduced antiplatelet effect of aspirin.     

The coagulation profile of preterm delivery

Introduction

Hypercoagulation was suggested to be involved in preterm birth etiology; however, the coagulation state of preterm parturients remains unelucidated. The study aim was to evaluate the haemostatic system of pregnant women with premature uterine contractions (PUC).

Materials and Methods

The cohort study population consisted of 76 healthy pregnant women admitted with regular PUC. The study group included 38 women who experienced preterm birth; 14 of them had preterm premature rupture of membranes (PPROM). The control group included 38 women who eventually had term delivery. Groups were matched for maternal age, number of births and gestational age at admission. Blood samples were tested for haemostatic parameters and coagulation activation markers.

Results

Significantly shorter PT and aPTT were documented in the study compared to control group (25.7 ± 2 vs. 27.4 ± 2.7 seconds, P = 0.003, and 9.96 ± 0.5 vs. 10.1 ± 0.4 seconds, P = 0.05, respectively), although differences in absolute values were small. There was no significant difference between the two groups in levels of: fibrinogen, D-dimer, protein C-global, free protein S antigen, factor VIII activity, Von Willebrand factor, plasminogen activator inhibitor-1, prothrombin fragments F1 + 2 (PT F1 + 2), tissue factor and tissue factor pathway inhibitor.Women with PPROM had significantly lower PT F1 + 2 levels compared to those who had preterm delivery with intact membranes (351 ± 99 vs. 561 ± 242 pmol/L, P = 0.003).

Conclusions

Shortened PT and aPTT, reflecting increased thrombotic activity in maternal plasma, could serve as a marker of real preterm labor in women with premature uterine contractions. Further prospective studies in a larger cohort are warranted to validate these findings.     

Lower tissue factor inhibition in patients with ST segment elevation than in patients with non ST elevation acute myocardial infarction

Introduction

Mechanisms to explain the different course of coronary thrombosis between ST elevation myocardial infarction (STEMI) and non-STEMI patients remain poorly defined. We hypothesize, however, that STEMI patients may present lower tissue factor plasma inhibition to partly account for their more persistent coronary thrombotic occlusion.

Materials and Methods

Total (t-TFPI ) and free tissue factor plasma inhibitor (f-TFPI), thrombin-antithrombin complex (TAT), plasminogen activator inhibitor 1 (PAI-1), von Willebrand factor (vWF), and fibrinogen were measured on admission and at 3 and 6 months in patients with a first STEMI (n:69) or non-STEMI (n:60). C reactive protein (CRP) was also measured on admission and at 3 months.

Results

STEMI patients showed lower admission levels of t-TFPI (p = 0.001), f-TFPI (p = 0.030) and fibrinogen (p = 0.022), and higher vWF levels (p = 0.005) than non-STEMI whereas TAT, PAI and CRP levels were comparable. At 3 and 6 months VWF, t-TFPI, f-TFPI, and TAT levels declined significantly in the 2 groups (p = 0.002) reaching similar values. CRP levels also declined at 3 months (p = 0.002). Moreover, the rate of cardiac mortality, non fatal MI or stroke during a 6 year follow-up were unrelated to admission coagulation parameters.

Conclusions

The lower inhibition of tissue factor and greater endothelial dysfunction in STEMI than in non-STEMI patients may enhance thrombosis at the culprit lesion and adjacent coronary plaques, and hence, account at least in part for their different pathophysiology. This condition, however, is limited to the acute phase.     

Activated factor XI and tissue factor in chronic obstructive pulmonary disease: links with inflammation and thrombin generation

Introduction

Increased cardiovascular mortality and risk of venous thromboembolism are serious extra-pulmonary complications of chronic obstructive pulmonary disease (COPD). Previously, circulating active tissue factor (TF) and factor XIa (FXIa) have been reported to be associated with acute coronary syndromes.

Objective

To measure plasma FXIa and active TF, prothrombin fragment 1.2 (F1.2), and markers of systemic inflammation (C-reactive protein [CRP], interleukin-6 [IL-6], tumor necrosis factor α [TNFα] and matrix metalloproteinase 9 [MMP-9]) in 60 patients with documented stable COPD free of previous thromboembolic events.

Methods

In-house clotting assays using inhibitory monoclonal antibodies against FXIa and TF.

Results

FXIa was detected in 9 (15%) and TF activity in 7 (11.7%) COPD patients. Subjects positive for FXIa and/or TF (n = 10; 16.7%) had higher F1.2 (median [interquartile range], 398 [216] vs 192 [42] pM, p < 0.000001), fibrinogen (5.58 [2.01] vs 3.97 [2.47] g/L, p = 0.0007), CRP (14.75 [1.20] vs 1.88 [2.95] mg/L, p < 0.000001), IL-6 (8.14 [4.74] vs 2.45 [2.24] pg/mL, p = 0.00002), and right ventricular systolic pressure (47 [15] vs 38 [12] mmHg, p = 0.023), and lower vital capacity (66 [15] vs 80 [17] % predicted, p = 0.04) than COPD patients without detectable FXIa and TF. COPD severity was not associated with the presence of circulating FXIa and active TF.

Conclusions

This is the first study to show that active FXIa and TF are present in stable COPD patients, who exhibit enhanced systemic inflammation and thrombin generation. Our findings suggest a new prothrombotic mechanism which might contribute to elevated risk of thromboembolic complications in COPD.     

Enhanced thrombin formation and fibrinolysis during acute Puumala hantavirus infection

Introduction

Nephropathia epidemica (NE) is a viral hemorrhagic fever with renal syndrome associated with thrombocytopenia and mild bleeding. We assessed activation of coagulation and fibrinolysis during the acute phase of NE.

Materials and methods

19 hospital-treated patients were involved. Plasma levels of D-dimer, prothrombin fragments 1 + 2 (F1 + 2), activated partial thromboplastin time (APTT), prothrombin time (PT%), thrombin time (TT), fibrinogen, antithrombin (AT), protein S free antigen (PS), protein C (PC) and complete blood count (CBC) were measured three times during the acute phase and once at 32-54 days after the onset of fever (recovery phase). Laboratory abnormalities were evaluated by the disseminated intravascular coagulation (DIC) scoring advocated by the International Society of Thrombosis and Haemostasis (ISTH).

Results

APTT was prolonged and D-dimer and F1 + 2 increased during the acute phase of NE. AT, PC and PS decreased, and TT was shortened, all implying increased thrombin generation. Acutely F1 + 2 was 3.4-fold and D-dimer even 24-fold higher compared with the recovery phase (median 726 vs 213 pmol/l, and median 4.8 vs 0.2 mg/l, respectively, p < 0.001 for both). Platelet count correlated with AT, PC, and PS (r = 0.73, r = 0.81, and r = 0.71, respectively, p < 0.001 for all) as well as with fibrinogen (r = 0.72, p < 0.001). Only five patients fulfilled the ISTH diagnosis of DIC.

Conclusions

During acute NE thrombocytopenia was associated with decreased natural anticoagulants, shortened thrombin time and enhanced fibrinolysis. Augmented thrombin formation and fibrinolysis characterize this hantavirus infection.     

The relationship between plasma and placental tissue factor, and tissue factor pathway inhibitors in severe pre-eclampsia patients

Objective

To investigate the mechanism underlying the hypercoagulable state in severe pre-eclampsia.

Methods

Plasma tissue factor (TF) and tissue factor pathway inhibitor (TFPI) expression from pre-eclampsia patients and healthy pregnant controls were determined by ELISA. Placental TF and TFPI gene and protein expression were detected by quantitative RT-PCR, immunohistochemistry, and Western analysis.

Results

The plasma TF level in the pre-eclampsia group was significantly higher than the control group (p < 0.01), and surprisingly, the plasma TFPI-1 and TFPI-2 in the pre-eclampsia group were significantly lower (p < 0.01). Placental TF gene and protein expression levels in the pre-eclampsia group was significantly higher than the control group, while TFPI-1 and TFPI-2 levels were significantly lower (p < 0.05). Lastly, a significant correlation was found between plasma and placental TF protein levels in the pre-eclampsia group (p < 0.01).

Conclusion

Higher expression and/or release of TF from the placenta may contribute towards a pathological hypercoagulable state in pre-eclampsia patients.