Mean Rate Index Research Articles

Heat strain while wearing pesticide protective clothing in hot environments: Effects of textile physical properties and ambient humidity

The purpose of this study was to investigate heat strain while wearing pesticide protective clothing (PPC) with different physical properties in hot environments. Eight young males participated in the following three PPC conditions [polyester/cotton work clothing (IT = 1.26 clo, Ret = 42.0 m2·PaW−1), Tyvek coverall (1.16 clo, 47.5 m2·PaW−1), and commonly used nylon suit with a microporous membrane (1.42 clo, 54.1 m2·PaW−1)] and in two environmental conditions (32 °C with 50% RH and 32 °C with 80% RH). All physiological variables (rectal and mean skin temperature, heart rate, and physiological strain index) and most subjective perceptions showed greater values in the 80% RH than in the 50% RH environment (all p < 0.05). Physiological burden was greater in the commonly used nylon suit condition than in the polyester/cotton work clothing condition (all p < 0.05), but in many variables there were no statistical differences between the Tyvek and nylon suit condition, especially in the 80% RH environment. There were no differences in humidity sensation during exercise among the PPC conditions, whereas, during recovery, subjects felt more humid in the Tyvek or nylon suit than in the polyester/cotton work clothing condition (p < 0.05). These results indicate that the 30%-higher humidity induced a greater physiological burden. However, physiological or subjective burden would not always be proportional or inversely proportional to the physical property level of PPC but was affected more by heat exchange modes between the human body and ambient environments.

Prospective Assessment of Clinical Risk Factors and Biomarkers of Hypercoagulability for the Identification of Patients with Lung Adenocarcinoma at Risk for Cancer Associated Thrombosis. the Observational Roadmap-CAT Study

INTRODUCTION: The aim of this prospective longitudinal study was to identify the most clinically relevant hypercoagulability biomarkers in lung adenocarcinoma patients for elaboration of an improved risk assessment model (RAM) for venous thromboembolism (VTE).METHODS: 150 ambulatory patients with lung adenocarcinoma were prospectively enrolled as well as a control group comprised of 30 healthy age & sex-matched individuals. Thrombin generation parameters, procoagulant phospholipid-dependent clotting time (Procoag-PPL), tissue factor activity (TFa), factor VIIa (FVIIa), factor V (FV), antithrombin (AT), D-Dimers (DDi), P-selectin and heparanase levels were assessed in platelet-poor plasma (PPP) at inclusion (baseline) and at the end of the 3rd chemotherapy cycle (acute phase). Cox regression analysis was used to identify independent VTE predictors.RESULTS: At baseline, patients had significantly attenuated thrombin generation, shorter Procoag-PPL, higher levels of TFa, D-Dimers and heparanase, and lower levels of FVIIa and P-selectin, compared to controls. A significant increase in Procoag-PPL, FV and FVIIa and a decrease of P-selectin levels was observed between baseline and the acute phase. Hospitalization within the last 3 months prior to assessment, time since cancer diagnosis less than 6 months, mean rate index of thrombin generation (MRI) and Procoag-PPL were independently associated with symptomatic VTE. Accordingly, a prediction model including the above parameters had improved discriminating capacity (area under the curve/AUC: 0.84).CONCLUSIONS: Ambulatory patients with lung adenocarcinoma may display pronounced blood hypercoagulability due to decreased Procoag-PPL, increased endothelial cell activation and increased degradation of fibrin. Incorporation of Procoag-PPL and MRI of thrombin generation may improve the accuracy of a VTE RAM in the above setting. DisclosuresNo relevant conflicts of interest to declare.

Stratification of Vascular Profile in Multiple Myeloma Patients Using Thrombin Generation Test

Introduction: Multiple myeloma (MM) is an hematological disease linked to a high thrombotic risk, estimated at around 10%/year, irrespective to disease onset. An important proportion of MM patients presents at least one of the well-defined vascular risk factors, such as diabetes, cardiac disease, hypertension or hyperlipidemia, which contribute to thrombotic risk. Thrombin Generation Test (TGT) could be an useful biomarker reflecting the prothrombotic profile of MM patients. Aim: To evaluate the potential correlation between vascular risk factors and TGT in MM patients. Materials and methods: This is a monocentric, prospective, non-interventional study on a cohort of 82 MM patients referred to the Hemostasis Center at Tenon University Hospital. Patients receiving already anticoagulant treatment of any kind were excluded. Thrombin generation was performed at their first visit using the Calibrated Thrombogram Assay (CAT®,Stago, Genevilliers, France), according to manufacturer's instructions. We collected all TGT parameters: lag time (LT), Endogenous Thrombin Potential (ETP) and Mean Rate Index (MRI).We also measured factor VIII activity (FVIII). Results were statistically analyzed using a two-sample t-test. Results: Among 82 patients with a male/female ratio of 44/35 and a median age at 65.2 years, 39 patients (48%) presented at least one cardiovascular risk factor (group A) and 42 had no vascular risk factors (group B) The LT value was reduced but not reaching a statistical difference between groups A and B (3 vs 3.95 sec, p= 0.8). MRI representing velocity was statistically shorter in group A (100 vs 118 nmol/min , p&amp;lt; 0.001). Surprisingly, ETP was significantly reduced in group A (1392 vs 1717 nmol/l x min, p &amp;lt; 0.001). FVIII levels were increased in group A (216% vs 192 %, p&amp;lt;0.05). Conclusion: MM hypercoagulability can be easily identified with MRI, a chronometric TGT parameter. Increased FVIII levels observed in vascular patients are also facilitating an accelerated thrombin generation and are correlated with an endothelial activation. ETP decrease, reflecting the link between both content and container, must be seen as an adaptative response. Thus, endothelial activation could lead to TFPI release and this particular TGT profile in high vascular risk MM patients with a hypercoagulable state. Disclosures No relevant conflicts of interest to declare.

Profile of Thrombin Generation Assay and Thromboelastometry in Women with Moderate and Severe Preeclampsia. the Roadmap-Preeclampsia Study

Introduction: Preeclampsia is a frequent vascular complication of pregnancy and figures among the major causes of maternal and neonatal morbidity and mortality. Early diagnosis and prompt, targeted treatment remain a unmet need. Hypercoagulability and endothelial cell activation are among the principal pathogenetic mechanisms in patients with preeclempsia. Development of diagnostic algorithms including clinically relevant biomarkers of hypercoagulability is expect to improve the management of preeclampsia. Among the numerous coagulation test, Global Coagulation Assays (GCA) such as thrombogram and thromboelastometry, could be of potential value for the evaluation of blood hypercoagulability. They provide information, on thrombin generation process, clot formation kinetics, clot firmness and even fibrinolysis potential. Aim: In this study we investigated the clinical accuracy of whole blood thromboelastometry (ROTEM®), and thrombin generation assay (calibrated automated thrombography: CAT® assay) to identify women with preeclampsia and we tried to compare their sensitivity. Methods: An observational retrospective case-control study was conducted. Plasma samples were collected from 84 women divided into three groups, the healthy pregnant (HP) group (n=35), the mild preeclampsia (MP) group (n=34) and the severe preeclampsia (SP) group (n=15). Thromboelastometry in whole blood was performed on ROTEM delta instrument (Tem Innovations GmbH, Werfen, Munich, Germany) with INTEM reagent. Thrombin generation triggered by PPP reagent low® (1 pM TF and 4µM phospholipid) was measured in platelet poor plasma. Thrombogram was also assessed in the presence or absence of thrombomodulin and the corresponding ration was calculated. Blood was collected at the diagnosis of preeclampsia (groups MP and SP) or at the equivalent months of pregnancy in the control group (HP). Statistical analysis was performed using the PASW Statistics 17.0.2 (SPSS Inc.) for Windows. Results: Thromboelastometry analysis showed that the clotting time (CT) was significantly longer in SP group as compared to MP and HP group. Both preeclampsia groups had longer clot formation time (CFT as compared to HP-group. MP-group had longer CFT as compared to SP-group. The α angle was significantly lower in SP-group as compared to the HP and MP groups. The maximum clot firmness was significantly higher in MP groups as compared to either HP or SP-group. The mean lysis (ML) was lower in both preeclampsia groups as compared to the HP group (Table 1). Thrombogram analysis showed that the lag-time of thrombin generation was significantly longer in both MP and SP groups as compared to HP group. Moreover, SP group showed significantly longer lag -time as compared to MP-group. Peak and the endogenous thrombin potential (ETP) were significantly higher in MP group as compared to either HP or SP groups. The mean rate index of the propagation phase of thrombin generation was not significantly different among the three groups whereas the thrombomodulin ratio for the ETP was significantly shorter in the SP-group (Table 2). Both tests showed a significant prolongation of the initiation phase of blood coagulation (reflected on CT and lag-time) in SP. The levels of clotting factors and fibrinogen were normal in all patients and none was on anticoagulant treatment. Thus, this prolongation reflects changes at the levels of TFPI and Thrmbomodulin reflecting an endothelial cell activation. ROTEM showed a decrease of the α-angle and MCF in SP group which is related with a lower platelet count in these patients. ROTEM showed enhanced fibrinolysis in both MP and SP groups Women with MP showed higher Peak and ETP than SP, MP showed higher ratio of ETP (TM+/TM-) than SP. Conclusion: The two GCA proved complementary information on the status of blood coagulation in pregnant women with preeclampsia. ROTEM provides information on clot formation kinetics and clot firmness as well as on fibrinolysis activation, which allow to differentiate SP from HP. However, the capacity of the assay for identification of patients with MP is limited. Thrombin generation assay showed a distinct profile between the three groups, which allowed differentiating the MP from HP as well as from SP. Disclosures No relevant conflicts of interest to declare.

Improved haemodynamic stability and cerebral tissue oxygenation after induction of anaesthesia with sufentanil compared to remifentanil: a randomised controlled trial

BackgroundBalanced anaesthesia with propofol and remifentanil, compared to sufentanil, often decreases mean arterial pressure (MAP), heart rate (HR) and cardiac index (CI), raising concerns on tissue-oxygenation. This distinct haemodynamic suppression might be attenuated by atropine. This double blinded RCT, investigates if induction with propofol-sufentanil results in higher CI and tissue-oxygenation than with propofol-remifentanil and if atropine has more pronounced beneficial effects on CI and tissue-oxygenation in a remifentanil-based anaesthesia.MethodsIn seventy patients scheduled for coronary bypass grafting (CABG), anaesthesia was induced and maintained with propofol target controlled infusion (TCI) with a target effect-site concentration (Cet) of 2.0 μg ml− 1 and either sufentanil (TCI Cet 0.48 ng ml− 1) or remifentanil (TCI Cet 8 ng ml− 1). If HR dropped below 60 bpm, methylatropine (1 mg) was administered intravenously. Relative changes (∆) in MAP, HR, stroke volume (SV), CI and cerebral (SctO2) and peripheral (SptO2) tissue-oxygenation during induction of anaesthesia and after atropine administration were analysed.ResultsThe sufentanil group compared to the remifentanil group showed significantly less decrease in MAP (∆ = − 23 ± 13 vs. -36 ± 13 mmHg), HR (∆ = − 5 ± 7 vs. -10 ± 10 bpm), SV (∆ = − 23 ± 18 vs. -35 ± 19 ml) and CI (∆ = − 0.8 (− 1.5 to − 0.5) vs. -1.5 (− 2.0 to − 1.1) l min− 1 m− 2), while SctO2 (∆ = 9 ± 5 vs. 6 ± 4%) showed more increase with no difference in ∆SptO2 (∆ = 8 ± 7 vs. 8 ± 8%). Atropine caused higher ∆HR (13 (9 to 19) vs. 10 ± 6 bpm) and ∆CI (0.4 ± 0.4 vs. 0.2 ± 0.3 l min− 1 m− 2) in sufentanil vs. remifentanil-based anaesthesia, with no difference in ∆MAP, ∆SV and ∆SctO2 and ∆SptO2.ConclusionInduction of anaesthesia with propofol and sufentanil results in improved haemodynamic stability and higher SctO2 compared to propofol and remifentanil in patients having CABG. Administration of atropine might be useful to counteract or prevent the haemodynamic suppression associated with these opioids.Trial registrationClinicaltrials.gov on June 7, 2013 (trial ID: NCT01871935).

P768 Potential utility of fully automated Doppler flow velocity tracing software in patients with atrial fibrillation

Abstract Background Stroke volume (SV) using Doppler echocardiography is a significant prognosticator in patients with atrial fibrillation (AF). However, tracing multiple left ventricular outflow tract (LVOT) Doppler flow velocity envelope is tedious. Although ASE recommends to average 5 -10 beats of SV in AF, this has not been validated. Recently developed fully automated Doppler flow velocity analytical software can analyze Doppler parameters in multiple consecutive beats on the screen within a few seconds. Purpose We aimed to determine the usefulness of the software, and to validate the minimum number of beats required to approximate SV in patients with AF. Methods We selected 21 AF patients who had undergone 2D echocardiography using GE ultrasound machine (E95, GE healthcare). LVOT area was calculated by 3.14×(LVOT diameter/2)². LVOT pulse-wave Doppler velocity was recorded from an apical approach with a quiet breathing. To maximize the number of flow envelope on the screen, sweep speed was set at 12.5 mm/s. LVOT velocity time integral was measured by both manual tracing method and fully automated method (Cardiac Auto Doppler, GE healthcare). The grand truth of mean SV (reference SV) in each patient was defined as the averaged values of SV from all consecutive beats. We also calculated the mean SV value with the successive addition of sequential beats started from the 1st beat. Each value was compared with the reference SV and % variability was calculated. We determined the minimum number of beats showing %variability becoming &amp;lt;5%. Results Mean age was 77 years. Mean heart rate and reference SV index (SVI) were 80 ± 12 bpm and 35 ± 10 mL/m2. A total number of beats for recording was ranged from 16 to 25 in each patient. The fully automated software could analyze Doppler envelope in 395 out of 412 beats (Feasibility: 96%). Although there was a good correlation of SV in individual beats between the manual and automatic method (r = 0.92), the automatic method significantly overestimated SV (mean bias: 2.6 mL, p &amp;lt; 0.001) compared with the manual method. The median values of minimum number of beats showing % variability &amp;lt; 5% were 4 (interquartile range: 2 -7) for manual tracing method. The corresponding values were 5 (2 -6) for automatic method. If we used mean values of SV during consecutive 10 beats, 92% of patients using manual method and 96% of patients using automatic method showed % variability &amp;lt; 5%. There were excellent correlation between reference SV and averaged SV from the 1st beat to 10th beat (manual: r = 0.98, automatic: r = 0.99). If we defined low flow status as &amp;lt; 35 mL/m2, averaged SVI during consecutive 10 beats using the automatic method had a correct diagnosis in 20 out of 21 patients. Conclusions We concluded that minimum number of required beats for averaging was 10 in most AF patients. Rapid and reliable SV analysis with a novel fully automated Doppler software has a potential for its adoption in busy echocardiography laboratories.

Indoor environmental assessment method in residential kitchen

Nowadays, energy consumption, environmental protection and safety are fundamental issues in design process. In order to reduce energy consumption, buildings become increasingly insulated and air tight. It has controversial effect on indoor environment, therefore, it has become essential to apply an effective ventilation system. This requires detailed design, especially if there is a strong, local source in the space. In residential buildings, gas stoves are significant source of gaseous pollutants and heat load. Indoor environmental assessments have been carried out in order to evaluate the key parameters. The aim of this studies is to develop a new design and monitoring method of residential kitchens with gas stoves. Primary results of laboratory researches indicate that the largest stovetop burner with power of 2.8 kW, has the main role. Significant emissions of NOx have been measured, in an average size kitchen (Vroom = 36 m3) the Hungarian standard NOx concentration level (200 ?g/m3) can be ensured with an exhaust air-flow of 1102 m3/h. With respect of thermal environmental parameters, heat loads of residential gas stoves could be characterized with convective heat transfer coefficient of 4.5 W/m2K and radiant heat transfer coefficient of 5.9 W/m2K. As regards thermal comfort parameters, predicted mean rate index in proved to be applicable in residential kitchens from ?0.3 to +2.0. However draught rating cannot be applied, with respect to the temperature limitations.

Prospective Assessment of Clinical Risk Factors and Biomarkers of Hypercoagulability for the Identification of Patients with Lung Adenocarcinoma at Risk for Cancer-Associated Thrombosis: The Observational ROADMAP-CAT Study.

The aim of this prospective study was to identify the most clinically relevant hypercoagulability biomarkers in lung adenocarcinoma patients for elaboration of an improved risk assessment model (RAM) for venous thromboembolism (VTE). One hundred fifty ambulatory patients with lung adenocarcinoma were prospectively enrolled. Thrombin generation, procoagulant phospholipid-dependent clotting time (Procoag-PPL), tissue factor activity (TFa), factor VIIa (FVIIa), factor V (FV), antithrombin, D-Dimers, P-selectin, and heparanase levels were assessed in platelet-poor plasma at inclusion (baseline) and at the end of the third chemotherapy cycle (third chemotherapy). Cox regression analysis was used to identify independent VTE predictors. At baseline, patients had significantly attenuated thrombin generation, shorter Procoag-PPL, higher levels of TFa, D-Dimers, and heparanase, and lower levels of FVIIa and P-selectin, compared with controls. A significant increase in Procoag-PPL, FV, and FVIIa and a decrease of P-selectin levels were observed between baseline and third chemotherapy. Hospitalization within the last 3 months prior to assessment, time since cancer diagnosis less than 6 months, mean rate index (MRI) of thrombin generation, and Procoag-PPL were independently associated with symptomatic VTE. Accordingly, a prediction model including Procoag-PPL and MRI showed significant discriminating capacity (area under the curve: 0.84). Ambulatory patients with lung adenocarcinoma may display pronounced blood hypercoagulability due to decreased Procoag-PPL, increased endothelial cell activation, and increased degradation of fibrin. Incorporation of Procoag-PPL and MRI of thrombin generation may improve the accuracy of a VTE-RAM in the above setting. The prospective ROADMAP-CAT study identified two biomarkers of hypercoagulability, the procoagulant phospholipid-dependent clotting time (Procoag-PPL) and the mean rate index (MRI) of the propagation phase of thrombin generation assessed with the Calibrated Automated Thrombinoscope, as being clinically relevant for the classification of ambulatory patients with lung adenocarcinoma receiving a maximum of one cycle of chemotherapy into high and intermediate/low risk for venous thromboembolism. Measurement of Procoag-PPL and MRI within 1 month after the administration of the first chemotherapy cycle provides significant accuracy of the assessment. Association of the Procoag-PPL and MRI with the clinical risk assessment model for cancer-associated thrombosis in ambulatory patients with solid tumors (COMPASS-CAT RAM) further improved its accuracy.

The Antithrombotic Potential of Tinzaparin and Enoxaparin Upon Thrombin Generation Triggered In Vitro by Human Ovarian Cancer Cells IGROV1.

A documented relationship between ovarian cancer and thrombosis does exist. Low-molecular-weight heparins (LMWHs) are cornerstone drugs in the primary prevention and treatment of venous thromboembolic events in patients with cancer. However, cancer cells may alter the efficiency of these antithrombotic agents. We aimed to characterize the procoagulant phenotype of human epithelial ovarian adenocarcinoma cells, IGROV1, and to compare the capacity of tinzaparin and enoxaparin to inhibit thrombin generation triggered by these cells. Thrombin generation induced by different concentrations of IGROV1 cells on platelet poor plasma (PPP) was assessed by the calibrated automated thrombogram assay. Tissue factor (TF) expression was studied using Western blot analysis. Then, the experimental model of thrombin generation was used to compare the inhibitory effect of clinically relevant concentrations of both tinzaparin and enoxaparin. The inhibitory concentration 50 (IC50) of the mean rate index and the endogenous thrombin potential and the 2-fold increase in lag time were analyzed on the basis of the anti-Xa and anti-IIa activities of the LMWHs. IGROV1 cells suspended into PPP resulted in a significant increase in thrombin generation in the absence of any exogenous source of TF and phospholipids. Tissue factor was expressed by IGROV1 cells. Tinzaparin was a more potent inhibitor of thrombin generation than enoxaparin. The inhibition of thrombin generation induced by IGROV1 cancer cells depended mainly on the anti-Xa activity of the LMWHs. This experimental study in ovarian cancer cells demonstrates that the antithrombotic activity of LMWHs is not completely predicted by the anti-Xa or anti-IIa activities measured in PPP.

Does Lipid Profile Affect Thrombin Generation During Ramadan Fasting in Patients With Cardiovascular Risks?

There is evidence that diet and variation in lipid metabolism can influence blood coagulation, but little is known about the effect of Ramadan fasting on plasmatic coagulation pattern. We investigated the effect of Ramadan fasting on thrombin generation (TG) in patients with cardiovascular disease (CVD) risks, and we aimed to assess the effect of lipid profile on TG parameters. The study was conducted in 36 adults having at least 2 CVD risks and in 30 healthy controls. Coagulation pattern was assessed by both classical clotting times and TG test. A complete lipid profile was performed simultaneously. Patients were invited 2 times: 1 week before Ramadan and during the last week of the Ramadan. The TG parameters were not different in patients with CVD risks compared to healthy controls. Fasting had no effect on plasmatic coagulation parameters and on TG profile. Individual analysis of the mean rate index (MRI) of TG revealed 3 groups: group 1 with no modification of MRI, group 2 with a significant increase in MRI (81.64 nM/min vs 136.07 nM/min; P < .001), and group 3 with a significant decrease in MRI (125.27 nM/min vs 73.18 nM/min; P = .001). Only in group 2, a significant increase was observed in total cholesterol and low-density lipoprotein cholesterol. Changes in lipid profile during Ramadan fasting did not influence the global coagulation pattern in patients with CVD risks. Whereas, a significant increase in the propagation phase of TG was associated with a significant increase in cholesterol levels, which was not found with the other TG parameters.

Newly Diagnosed Multiple Myeloma Is Associated with Enhanced TF Pathway Activation, Thrombin Generation and Increased Concentration of Procoagulant Microparticles

Background: Multiple myeloma (MM) and plasma cell dyscrasias (PCD) are associated with increased risk of venous thromboembolism (VTE) which is further enhanced by treatments with immunomodulatory agents, melphalan or steroids. The optimization of VTE prevention in patients with MM is an unmet need. According to Virchow's triad, blood hypercoagulabilty is one of the three conditions required for thrombosis. Elaboration of a risk assessment model, which includes biomarkers of hypercoagulability, could lead to better identification of MM patients eligible for pharmacological thromboprophylaxis.Aims: We conducted a longitudinal observational study, to explore the relationship of MM with cellular and plasma hypercoagulability aiming to identify the most relevant biomarkers which could be used in the RAM for VTE.Materials and Methods: Newly diagnosed patients (n=72) with PCD were recruited from July 2014 to May 2015. The control group (CG) was consisted of 30 healthy age and sex-matched individuals. A systematic compression ultrasound was performed at baseline and 6 months post-therapy. Blood samples were obtained at time of diagnosis and at 3-6 months post therapy. Samples of platelet poor plasma were assessed for thrombin generation (TG) with the PPP-Reagent® (5pMTF and 4μM phospholipids), P-selectin, D-dimers (D-Di), activated FVII (FVIIa), Tissue Factor (TFa), fibrin monomers (FM), and procoagulant phospholipid dependent clotting time (PPL-ct). The upper and lower normal limits (UNL and LNL) were calculated by the mean±2sd. We present herein the data obtained at the inclusion of the patients.Results: Forty-three patients had MM, 16 had asymptomatic MM (AMM), 13 had MGUS. The median age was 68 years (40-84 years); 44% of patients were males. The median time to follow up was 6 months (range: 2-12 months). Patients with PCD as compared to the CG had significantly shorter PPL-ct, which it has been shown that it is inversely correlated with the concentration of platelet derived procoagulant microparticles. PCD patients had also lower Endogenous thrombin potential (ETP), shorter time to thrombin Peak (ttPeak) and lower mean rate index (MRI) of the propagation phase of TG as compared to the controls. The levels of P-selectin were not significantly different between the two groups. Patients with MM as compared to MGUS and AMM patients had significantly higher levels of TFa, FVIIa, FM, D-Di, Peak and MRI (Table 1). Among MM patients 72% had PPL-ct below the LNL, 62% and 28% had TFa and FM above the UNL respectively, 4% had MRI above the UNL and 29% had MRI below the LNL. Among patients who received therapy, 46% also received thromboprophylaxis with either aspirin (76%, n=22) or LMWH (24%, n=5); all were MM patients who received IMiD-based therapies. During the follow-up period the rate of VTE events in MM patients was 7% (all MM patients under treatment).Conclusion: In patients with PCD increased procoagulant microparticles of cellular origin is a generalized phenomenon. In addition, patients with MM present significant TF pathway activation and increased in vivo TG. A significant part, but not all of the patients present strong signs of plasma hypercoagulability. The finding of high inter-individual variability of TG underlines the heterogeneity of blood coagulation alterations in MM patients. The data of the prospective part of this study will allow to validate the clinical significance of this finding.Table 1Biomarkers of plasma and cellular hypercoagulablity in newly diagnosed patients with PCD. ETP: endogenous thrombin potential; MRI: mean rate index of the propagation phase of thrombin generation. FM: fibrin monomersParametersControls (n=30)MGUS (n=13)AMM (n=16)MM (n=43)PPL (sec)62.8±8.638.1±8.2*41.3±6.8*39.9±13.7*P-Selectin (pg/ml)62660±1039035127±1246229697.7±9090.4536223±13638FTa (ng/ml)0.3±0.12.1±1.4*1.9±1.3*7.5±23.3*$FVIIa (U/ml)50.9±10.660.2±27.564.4±48.6102.1±203.5*$FM (μg/ml)3.5±0.88.1±8.4*5.7±1.7*17.7±38.3*$D-Di (μg/ml)0.3±0.11.1±1.10.6±0.51.8±2.8*$Thrombin generationLagtime (min)2.5±0.43.4±1.23.43±0.714.2±2.3*$ETP (nM/min)1496±1911029±2051045.87±288.91202±516$Peak (nM)289±36168±60174±64216±74$ttPeak (min)5.3±0.77.3±1.87.17±1.237.1±2.7MRI110±2448±2452±2882±44$*p<0.05 versus Controls$p<0.05 versus MGUS and SMM DisclosuresVan Dreden:Diagnostica Stago: Employment. Dimopoulos:Janssen-Cilag: Honoraria; Celgene: Honoraria; Janssen: Honoraria; Novartis: Honoraria; Amgen: Honoraria; Genesis: Honoraria; Onyx: Honoraria.

Generic and Branded Enoxaparin Bioequivalence: A Clinical and Experimental Study

Our aim is to compare a new generic version of enoxaparin (Enoxa®) with the parent brand (Lovenox®). We included patients with acute coronary syndrome (ACS) for the clinical study and healthy volunteers for the experimental study. ACS patients randomly assigned to receive a bolus of Enoxa® (n=86) or Lovenox® (n=83) and serum anti-Xa activity was measured 4 hours thereafter. For experimental study, blood from healthy volunteers was used to compare the effect of both formulations on thrombin generation in citrated platelet-poor plasma (PPP). The half maximal inhibitory concentration of the drug (IC50) that is required to inhibit 50% in-vitro thrombin generation parameters, mean rate index (MRI) and endogenous thrombin potential (ETP). Both IC50 MRI and IC50 ETP were calculated in PPP. In ACS patients, serum anti-Xa activity was found not different between Enoxa® and Lovenox®. Median anti Xa activity measured 4 hours after the initial bolus was 0.39 IU anti-Xa/ml [95 % CI 0.31-0.53] and 0.34 IU anti-Xa/ml [95% CI 0.27-0.53], for the Enoxa® group and Lovenox® group respectively. No difference in major cardiovascular events was observed during hospital stay. In healthy volunteers, IC50 MRI and IC50 ETP were similar between Lovenox® and Enoxa® in PPP [(2.5 μg/ml ± 0.2 μg/ml) versus (2.3 μg/ml ± 0.1μg/ml) respectively for IC50 MRI; (p=0.2)] and [(4.8 μg/ml ± 0.8 μg/ml) versus (4.1 μg/ml ± 0.1 μg/ml) respectively for IC50 ETP; (p=0.2)]. With both formulations, anti-Xa activity and anti-Xa/anti-IIa ratio were similar. The generic enoxaparin Enoxa® met the main regulatory criteria of bioequivalence with the branded product.

Effect of Low Molecular Weight Heparins and Fondaparinux Upon Thrombin Generation Triggered by Human Pancreatic Cancer Cells BXPC3

Low molecular weight heparins (LMWHs) and fondaparinux are widely used for prophylaxis and treatment of venous thromboembolic disease in cancer patients. However, the optimization of the antithrombotic treatment especially in patients with adenocarcinoma of the pancreas is a challenging issue. The understanding of the mechanism of action of the LMWHs and fondaparinux in cancer-induced hypercoagulability might help to optimize antithrombotic treatment. To this aim, we investigated the influence of BXPC3 pancreas adenocarcinoma cells on the antithrombotic activity of LMWHs and fondaparinux. Thrombin generation (TG) in normal platelet poor (PPP) and platelet rich plasma (PRP) spiked with clinically relevant concentrations of dalteparin, enoxaparin, nadroparin tinzaparin and fondaparinux was assessed with the Calibrated Automated Thrombogram assay. BXPC3 (5 cells/μl) were added to plasma. The mean rate index (MRI) of the propagation phase of TG and the endogenous thrombin potential (ETP) were analyzed. The IC50 of the studied compounds were determined and compared on the basis of anti-Xa and anti-IIa equivalent units. We demonstrate that the specific antithrombin (AT)-dependent anti-Xa activity of LMWHs and fondaparinux almost selectively inhibits the propagation phase of TG. The synergy between the anti-Xa and anti-IIa activities of LMWHs rather than the selective inhibition of FXa warrants abrogation of TG. The mean molecular weight and anti-Xa/anti-IIa ratio of the AT-dependent agents cannot predict the alteration of their capacity to inhibit TG. Tinzaparin was the most potent inhibitor of TG than the other LMWHs. Enoxaparin was more potent than nadroparin and dalteparin.

Use of Thrombin Generation Assay As Tool for the Evaluation of the Antithrombotic Samenesse of Enoxaparine Copies

Background. The protection rights of LMWHs expired or are expiring, so the extent and nature of the studies required to obtain a market authorization for LMWH copies is an issue of debate. The actual situation, which is characterized by the increasing number of enoxaparin copies available worldwide, makes the definition of criteria for the biological similarity between LMWHs copies and the original product a real need.Aim. The present study, conducted in vitro, offers an analytical approach for the comparison of branded enoxaparin and its copies using a standard pharmacological assay (the measurement of the specific anti-Xa activity) and the calibrated automated thrombogram performed in human platelet rich or platelet poor plasma (PRP and PPP) as well as in an experimental model of hypercoagulability induced by cancer cells. The study aims to provide an integrated rational for the determination of the criteria for the similarity and sameness of branded and copies of enoxaparin.Methods. The studied copies of enoxaparin were Cutenox®, Dilutol®, Enoxa®, Fibrinox®, Loparin®, Lupenox®, Novex®, Noxprin®, Versa®. Samples of PPP and PRP from 15 volunteers were spiked with 2-20 µg/ml of branded (Lovenox®) or copies of enoxaparin. The specific anti-Xa activity in PPP was measured with the Rotachrom® assay. Thrombin generation in PPP and PRP in the presence of tissue factor or pancreatic cancer cells BXPC3 was assessed with the Calibrated Automated Thrombogram. Among thrombogram parametersn the Mean Rate Index (MRI) of TG propagation phase of thrombin generation was analysed. The concentrations inhibiting 50% (IC50) the MRI were calculated.Results . The specific inhibitory potency of enoxaparin copies against factor Xa ranged from 0.072 to 0.088 anti-Xa IU/μg, being lower as compared to that of the branded enoxaparin (0.095 anti-Xa IU/μg). the branded enoxaparin induced a concentration dependent inhibition of thrombin generation. The IC50 values revealed significant differences among the studied copies of enoxaparin and between each one of them and the branded enoxaparin. The potency of each copy of enoxaparin to inhibit thrombin generation as compared to the branded product varied in the three experimental systems. the presence of platelets or pancreatic cancer cells in human plasma induces significant modifications of the inhibitory potency of enoxaparin copies on thrombin generation, which distinguish them not only from the branded enoxaparin but also among them.Conclusion. the copies of enoxaparin which respond to the criteria of sameness to the branded enoxaparin according to the pharmacological criteria endorsed by health authorities demonstrate a significant variability regarding their inhibitory potency on thrombin generation. The presence of platelets and cancer cells significantly influence the variability of the antithrombotic efficiency of the enoxaparin copies as compared to the branded product. The findings of the present study underline the need for the elaboration of functional criteria which evaluate the global antithrombotic capacity of enoxaparin copies in order to evaluate their potential sameness with the branded drug. DisclosuresNo relevant conflicts of interest to declare.

Distinct Roles Of Antithrombin-Dependent Antithrombotic Agents (Lovenox, Fondaparinux) and Direct Anti-Xa Anti-Coagulant (Apixaban) On The Inhibition Of Thrombin Generation Induced By Human Pancreatic (BXPC3) and Human Breast (MCF7) Cells

IntroductionThe optimization of the antithrombotic treatment with LMWH (enoxaparin), direct and indirect anti-Xa ( Apixaban, fondaparinux), in patients with adenocarcinoma of the pancreas, or human breast carcinoma is a challenging issue. The understanding of their mechanism of action in cancer-induced hypercoagulability might provide evidence for treatment optimization. To this aim, we studied the influence of pancreas adenocarcinoma cells (BXPC3), or human breast carcinoma cells (MCF7) on the antithrombotic activity of enoxaparin, fondaparinux and apixaban. Materials and MethodsCells were cultured and adhered in 96-well plates (50cells/µl). Thrombin generation (TG) of normal platelet poor plasma spiked with clinically relevant concentrations of enoxaparin, fondaparinux and apixaban which was added in wells carrying cancer cells was assessed with the Calibrated Automated Thrombogram assay. In the control experiment TG was triggered using PPP-Reagent 5 pM TF. The lag-time of thrombin generation, the maximum concentration of thrombin (Peak), and the mean rate index (MRI) of the propagation phase of thrombin generation were analysed [MRI=Peak/(ttPeak-lag-time)]. The IC50 of the studied compounds were calculated by extrapolation from the concentration-response curve, and compared. ResultsAll studied antithrombotic agents inhibited in a concentration dependent manner the thrombin generation. The three studied agents significantly inhibited TG at plasma concentrations usually achieved at doses for thromboprophylaxis. However the presence of cancer cells and their type was determinant for the antithrombotic potency of the studied drugs. Comparison on the basis of IC50 showed that the presence of either BXPC3 or MCF7 cells did not significantly modify the antithrombotic potency of enoxaparin as compared to the control experiment. In contrast the inhibitory effect of fondaparinux and apixaban on thrombin generation was partially reversed when TG was triggered by BXPC3 since the IC50 were significantly increased as compared to the control experiment. The presence of MCF7 cells did not significantly modify the antithrombotic activity of apixaban and fondaparinux.IC50 for PeakIC50 for MRIPPP(without cells)PPP+ BXPC3PPP+ MCF7PPP (without cells)PPP+ BXPC3PPP+ MCF7Lovenox (anti-Xa IU/ml)0.0500.0510.0460.100.0950.088Arixtra (anti-Xa IU/ml)0.580.780.410.3100.8120.367Apixaban (ng/ml)17.0223.9318.6612.527.28.0 ConclusionsThe LMWH enoxaparin and the specific FXa inhibitors apixaban and fondaparinux demonstrate potent inhibitory capacity on thrombin generation triggered by cancer cells. The type of cancer cells is determinant for the antithrombotic efficiency of the specific factor Xa inhibitors independently of their mechanism of action (i.e. antithrombin dependent or independent inhibition of FXa). In contrast the type of cancer cells does not significantly influence the potency of enoxaparin. This is probably due to the presence of the trace amounts of anti-IIa activity. The present study stresses out that the impact of the type of cancer cells on the antithrombotic activity of the specific Xa inhibitors should not be neglected. These data have to be taken into consideration for the design of dose-finding studies of the direct orally active FXa inhibitors in patients with different histological types of cancer. Disclosures:No relevant conflicts of interest to declare.

In Vitro Evaluation of the Procoagulant Properties of Autologous Peripheral Blood Stem Cell Transplant

AbstractAbstract 1134 Background:Autologous transplantation is a treatment option for bone marrow toxicity induced by chemotherapy and/or radiotherapy in cancer patients. Although it improves patient survival, autologous transplantation is associated with thrombotic complications. The procoagulant properties of autologous peripheral blood stem cell transplant (APBSCT) have never been characterized.The aim of this study was to determine in vitro the procoagulant properties of APBSCT transfused in patients with solid tumors. Methods:Samples of APBSCT from 10 consecutive patients eligible for autologous transplantation were studied. The ability of APBSCT to induce in vitro thrombin generation in normal platelet poor or rich plasma (PPP or PRP respectively) was evaluated. The APBSCT was diluted 1/10 in PPP or PRP. Thrombin generation was measured using the Calibrated Automated Thrombogram (Thrombinoscope bv Stago France). In control experiments the APBSCT was replaced by saline. Platelet- and erythrocyte-derived microparticles (PdMP and EdMP respectively) were determined by flow cytometry using monoclonal antibodies anti-CD41-PE and anti-CD235a-PE respectively. Five out of 10 samples of APBSCT were also studied for tissue factor (TF) and phosphatidylserine (PS) expression. The TF was revealed by the monoclonal antibody anti-CD142-PE and PS by annexin V-FITC. Results:In both PPP and PRP experiments, APBSCT increased thrombin generation compared with the controls. In the presence of the APBSCT, the chronometric parameters of the thrombogram (lag time and time-to-peak) were significantly shorter and the peak and mean rate index (MRI) were significantly increased as compared to the experiment controls. The endogenous thrombin potential (ETP) was the only parameter of the thrombogram that was not influenced (Table). Increased expression of PdMP was noticed in APBSCT samples as compared to the control group (23979 ± 29 204 versus 752 ± 432, p <0.001). No significant difference was found in EdMP (55 ± 67 versus 69 ± 49, p> 0.05). In the five samples PS had a greater mean fluorescence intensity as compared to the control group (PS = 25 ± 6 versus 9 ± 4, p <0.01). In contrast, TF was not significantly different (FT = 5 ± 4 versus 4 ± 2, p> 0.05). Conclusion:The APBSCT used for autologous transplatation in patients with solid cancer accelerate in vitro thrombin generation in PPP and PRP and presents significant procoagulant properties. These procoagulant properties of APBSC are related to an important expression of PdMP and PS. Whether the transfusion of the APBSCT induces a hypercoagulable state in vivo that merits further investigation.Thrombin generation in PPPThrombin generation in PRPParameters of thrombogramAPBSCTSalineAPBSCTSalineLag-time (mn)7.28 ± 1.87**16.65 ± 8.237.10 ± 1.55**13.75 ± 6.09Time to Peak (mn)10.87 ± 2.70**22.19 ± 10.1410.38 ± 2.37**19,89 ± 8,12Peak (nM)262.32 ± 81.87*123.32 ± 107.72284.21 ± 75.15*198.67 ± 58.11ETP (nM.mn)1667.55 ± 418.031237.15 ± 887.381753.05 ± 410.921675.20 ± 691.93MRI (nM/mn)84.69 ± 48.27*33.05 ± 38.4199.57 ± 48.37*40.96 ± 27.99Table: Parameters of thrombogram. * p<0.05, ** p<0.01 APBSCT induced thrombin generation was compared to saline experiments. APBSCT: autologous peripheral blood stem cell transplant, PPP: Plasma poor in platelets, PRP: plasma rich in platelets, ETP: endogenous thrombin potential, MRI: mean rate index. Disclosures:No relevant conflicts of interest to declare.

Markers of Hypercoagulability in Breast Cancer: What Is Their Clinical Relevance?

AbstractAbstract 5133 IntroductionCancer is generally combined with an increased risk of venous thromboembolism. This risk is linked to a hypercoagulable state whose precise mechanism remains unclear. It depends on the histological type, the stage of cancer and the anti-neoplasic treatment. This study aims to identify a hypercoagulability in patients with breast cancer and to define the most relevant procoagulant markers. Materials and methodsA prospective study was carried out at the day hospital in the cancer department of the University Hospital H. Bourguiba in Sfax-Tunisia, from January to June 2012, including only patients with breast cancer. The thrombin generation was carried out on a venous citrated sampling (3. 2%) according to the technique of Calibrated Automated Thrombogram assay (CAT®, Diagnostica Stago, Asnières, France). The parameters of the thrombogram were analyzed: endogenous thrombin potential (ETP), peak of thrombin (peak) and mean rate index (MRI). The rates of platelet-derived microparticles expressing phosphatidyl-serine (MPP-PS+) were determined by flow cytometry using monoclonal antibodies anti-CD41 and anti-annexin V marked respectively by phycoerythrin (PE) and fluorescein isothiocyanate (FITC). D-dimers were measured by the STA-Liatest D-DI (Diagnostica-Stago) technique. The procoagulant activity of phospholipids (PPL) was measured by STA®-Procoag-PPL (Diagnostica-Stago). The plasma levels of tissue factor (TFa) were measured in a one-stage kinetic chromogenic method. This home-assay measures the ability of TF-FVIIa to activate factor X. ResultsSixty one patients were included. Their mean age was 51. 8 ± 10. 9 years old. The study of the thrombogram parameters showed a significant increase of the peak of thrombin (343. 8±79. 2 nM) and of the velocity or MRI (153±56 nM/min) in patients compared to control subjects (288±48 nM, p=0. 001 and 109±33 nM/min, p<0. 001 respectively). Only 36% of patients had a significant increase of thrombin generation. D-dimers levels reached in average 1230±1760 ng/ml and 61% of patients presented relevant high values (>500 ng/ml). MPP-PS+ in cancer patients were significantly higher (9684±7865/μl) than in controls (695±361/μl, p<0. 001) but nearly 94% of patients present particularly high levels of this parameter (≥1614/μl). PPL levels were significantly higher in patients with a shorter time compared to controls (43. 4±10. 4sec versus 72 sec ± 5. 6 sec) with 97% of cancer patients below the inferior limit (60. 8sec). Besides, TFa levels were significantly increased in patients (1. 6±1. 2 pM) compared to controls (0. 22pM ± 0. 12) with 87% of cancer patients presenting particularly high values (≥0. 46pM). ConclusionBreast cancer, considered more like a tumor with a low vascular risk, is combined with a state of cell activation and hypercoagulation, almost constant, reflected by an increase of procoagulant microparticles, TF and PPL levels. Besides, thrombin generation showed a less pronounced increase in this clinical context and could contribute to discriminate patients with high or low high risk of thrombosis in breast cancer patients. This has to be confirmed by prospective studies with a clinical follow-up of cancer patients. Disclosures:No relevant conflicts of interest to declare.

Hypercoagulability Linked to Breast Cancer Depends On the Stage and the Duration of the Tumor Evolution

AbstractAbstract 3396 IntroductionThe risk of venous thromboembolic event (VTE) in patients with cancer is particularly increased compared to normal population. It seems that this risk depends largely on the characteristics of the tumor, such as its site or its stage of evolution, and the anti-neoplasic treatment. The capacity of thrombin generation and D-dimers levels are two biological markers proposed for the stratification of the risk of VTE. We have analyzed thrombin generation and D-dimers levels in patients with breast cancer as markers of a hypercoagulable state, depending on the stage and the period of the tumor evolution. Materials and methodsIt is a prospective study carried out at the day hospital of the carcinology department of the University Hospital H. Bourguiba in Sfax-Tunisia, including patients with breast cancer at different stages of evolution and different period elapsed since cancer diagnosis. At the time of inclusion, a venous citrated blood sampling (3.2%) was made. The test of thrombin generation was carried out according to the technique of Calibrated Automated Thrombogram assay (CAT®, Diagnostica Stago, Asnières, France). The parameters of the thrombogram were analyzed: endogenous thrombin potential (ETP), peak of thrombin (peak) and mean rate index (MRI). D-dimers were measured using the STA®- Liatest® D-Di assay (Diagnostica-Stago). ResultsSixty one patients were included. Their average age is 51.8 ± 10.9 years old. Depending on the stage of cancer disease, 3 sub-groups of patients were distinguished: early local stage (T1, n=16), advanced local stage (T2-T4; n=25) and metastatic stage (M; n=20). Considering the time passed since diagnosis, we have different periods : inferior to 6 months (n=26), 6 to 12 months (n=7), 12 to 36 months (n=15) and more than 36 months (n=13). The analysis of the different parameters of the thrombogram depending on the cancer stage revealed that patients with an advanced local stage and a period elapsed since cancer diagnosis inferior to 6 months had significantly higher values of ETP and thrombin peak (1708±247 nM.min and 379±80 nM) compared to those with an older cancer (1404±308 nM.min, p<0.05 and 321±52, p<0.05 respectively). The study of D-dimers levels depending on the stage of cancer revealed an increase of this marker according to the severity of the cancer. Patients with metastatic stages have the highest levels (1937 ± 2468 μg/l) compared to patients with an early local stage (615±456 μg/l, p<0.05 ). In addition, the period of time since cancer diagnosis does not have any influence on D-dimers levels. ConclusionThe evaluation of the capacity of thrombin generation and D-dimers levels showed that these biological parameters are indeed linked to the stage of evolution and the severity of breast cancer. Therefore, these biological tests underlying an hypercoagulable state have a potential and complementary importance to stratify the risk of VTE in this context. This should be confirmed by the prospective follow-up of the thromboembolic risk existing in the patients with breast cancer. Disclosures:No relevant conflicts of interest to declare.

1697P - Semuloparin Efficiently Inhibits Thrombin Generation Triggered by Pancreas Adenocarcinoma Cells BXPC3. Distinct Roles of Anti-XA and Anti-IIA Activity

ABSTRACT Background Venous thromboembolism (VTE) is a common complication in patients with cancer receiving chemotherapy. Currently no anticoagulant is approved for VTE prophylaxis in this setting. Semuloparin is an ultra-LMWH generated through a highly selective depolymerization of heparin which protects the antithrombin (AT) binding site in order to improve the benefit/risk ratio compared to existing anitcoagulants. Aims We studied in vitro the mechanism of action of semuloparin on the inhibition of thrombin generation (TG) of human platelet poor plasma (PPP) triggered by human pancreatic cancer cells BXPC3. We compared the antithrombotic efficiency of semuloparin to that of enoxaparin and the specific AT-dependent factor Xa inhibitor fondaparinux. Materials and methods BXPC3 cells were suspended in PPP spiked with clinically relevant concentrations of semuloparin, enoxaparin and fondaparinux. The endogenous thrombin potential (ETP) and the mean rate index (MRI) of the propagation phase of TG were monitored with the CAT assay (Stago France) as described previously (Gerotziafas et al Thromb Res 2011). Anti-Xa and anti-IIa specific activities were assessed assays obtained from Diagnostica Stago. Results Both semuloparin and enoxaparin, at the concentration of 0.4 anti-Xa IU/ml, completely abrogated TG. Total inhibition of TG occured in the presence of 0.002 anti-IIa IU/ml of semuloparin and 0.05 anti-IIa IU/ml of enoxaparin. Fondaparinux, even at concentrations higher than 2 µg/ml, reduced the MRI but did not significantly affect the ETP and did not completely inhibited TG,. The IC50 for the ETP of the anti-IIa activity of enoxaparin was 37-fold higher as compared to that of semuloparin. Conclusion In a cancer cell model of hypercoagulability, semuloparin reduced efficiently thrombin generation. The unique anticoagulant profile of semuloparin based on its high AT-affinity differentiates it from enoxaparin and fondaparinux. The residual anti-IIa activity of semuloparin amplifies its antithrombotic efficacy. This profile is expected to translate into an improved benefit/risk ratio. Disclosure All authors have declared no conflicts of interest.

O.05b Low molecular weight heparin actions on human endometrial angiogenesis

s / Thrombosis Research 127 (2011) S123–S150 S125 O.04b Effect of the dose of oral treatment with 17beta-estradiol associated with dydrogesterone on thrombin generation in healthy postmenopausal women: a randomized double-blind placebo-controlled study G. Gerotziafas *, V. Galea, A. Rousseau, D. Torchin, K.F. Zannad, K. Lacut, J. Demolis, T. Simon, I. Elalamy. ER2UPMC, Faculte de Medecine Pierre et Marie Curie, Universite Paris 6, Hopital Tenon, APHP, Paris, Clinical research Unit, Department of Clinical Pharmacology, APHP, Saint-Antoine hospital, Paris 6 University, Paris, Department of Gynaecology, APHP, Saint-Antoine hospital, Paris, Clinical Investigation Center, CHU, Nancy, Clinical Investigation Center, CHU, Brest, Clinical Investigation Center, Department of Clinical Pharmacology, AP-HP Saint-Antoine hospital, Paris 6 University, Paris, France Introduction: Increased risk of venous thrombosis during oral hormone therapy in postmenopausal women is related to estrogen-induced hypercoagulable state. Lower estrogen dose is recommended, but the effect of hormone dose optimisation on haemostasis has not been studied. Aim of the study: To evaluate the influence of two different doses of daily oral 17beta-estradiol therapy compared with placebo, on thrombin generation (TG) in healthy postmenopausal women. Materials-Methods: Seventy two menopausal women were randomized to receive daily 1mg (n =24) or 2mg (n =26) of 17beta-estradiol associated with 10mg dydrogesterone or placebo (n =22). TG was monitored before and 2 months after treatment using the Calibrated Automated Thrombogram® (Stago, France). Results: At baseline parameters of TG were not statistically different in the three study groups. Two months after randomisation, lag time and time to reach the peak of thrombin were decreased while the mean rate index and the peak of thrombin were significantly increased in the two groups of hormone-treated women as compared to placebo group. Endogenous thrombin potential remained unchanged. No difference was observed in TG parameters between women receiving lower and higher dose of 17betaestradiol. Conclusions: Oral hormone therapy with 2mg of 17beta-estradiol for two months induced acceleration and increase of TG. Lowering the dose by 1mg did not attenuate this effect. On the contrary endogenous thrombin potential was not influenced in any dose. The clinical significance of the profile of TG of postmenopausal women being on hormone therapy remains to be explored. Table 1: Parameters of thrombin generation 2 months after randomisation (Treatment with two different doses of 17beta-estradiol associated with dydrogesterone or placebo) placebo 17beta-estradiol