Postpartum haemorrhage related early increase in D-dimers is inhibited by tranexamic acid: haemostasis parameters of a randomized controlled open labelled trial.

BACKGROUND: Beneficial effects of tranexamic acid (TA) have been established in surgery and trauma. In ongoing postpartum haemorrhage (PPH), a moderate reduction of blood loss was observed in a previously published randomized controlled trial. Analysis of haemostasis parameters obtained from samples collected as part of this study are presented. METHODS: Women with PPH >800 ml after vaginal delivery were assigned to receive either TA (4 g over 1 h, then 1 g per h over six h) (TA) or not (H). A non-haemorrhagic group (NH), <800 ml blood loss, was included as postpartum reference. At four time-points (enrolment, +30 min, +2 h, +6 h), haemostasis was assessed. Haemostasis assays were performed blinded to group allocation. Data were expressed as median [interquartiles] and compared with non-parametric tests. RESULTS: In H compared with NH group, D-dimers increase (3730 ng ml(-1) [2468-8493] vs 2649 [2667-4375]; P=0.0001) and fibrinogen and factor II decrease were observed at enrolment and became maximal 2 h later. When comparing TA to H patients, the increase in Plasmin-Antiplasmin-complexes at +30 min (486 ng ml(-1) [340-1116] vs 674 [548-1640]; P=0.03) and D-dimers at +2 h (3888 ng ml(-1) [2688-6172] vs 7495 [4400-15772]; P=0.0001) was blunted. TA had no effect on fibrinogen decrease. CONCLUSIONS: This study provides biological evidence of an early increase in D-dimers and plasmin-antiplasmin complexes associated with active post-partum haemorrhage and its attenuation by the early use of a clinically effective high dose of TA, opening the perspective of dose ranging studies to determinate the optimal dose and timing in this setting. CLINICAL TRIAL REGISTRATION: ISRCTN09968140.

Assessment of anti-factor Xa activity of heparin in binary parenteral nutrition admixtures for premature neonates.

An in vitro study was carried out to determine the anti-Xa activity of heparin in binary parenteral nutrition (BPN) admixtures for premature neonates in our neonatal intensive care unit (NICU) after a 24-hour infusion, as well as to assess drug interaction with a 50% glucose solution. Two types of bags were prepared: (1) BPN admixtures (composition defined in the NICU) including sodium heparin at 77 UI/mL and (2) bags containing only G50% with sodium heparin at 193 UI/mL. The anti-Xa activity of heparin was measured in bags at T0, after the 24-hour infusion and in eluates at the outlet of the infusion line after 24hours, using a validated chromogenic anti-Xa method. Comparisons of the mean concentration observed with the theoretical value for anti-Xa activity were performed with the Student t-test. Mean values of anti-Xa activity do not differ significantly from the values expected for all conditions. We found a slight variation in anti-Xa activity when infused over 24hours for both types of bags, with and without in-line filtration, showing that heparin remains stable during this infusion period in both BPN admixtures and G50%.

[Evaluation of D-dimer as a marker for severity in pregnancies with preeclampsia]. / Intérêt du dosage des D-dimères comme marqueurs de sévérité en cas de prééclampsie.

OBJECTIVES: Alterations in blood coagulation and fibrinolysis play a major role in the pathogenesis of preeclampsia. HELLP syndrome is associated with hypercoagulability and leads to maternal and perinatal complications. Our purpose was to evaluate D-dimer as a marker for severity in pregnancies with preeclampsia. PATIENTS AND METHODS: Plasma D-dimer levels were measured using an enzyme-linked immunosorbent assay (ELISA) technique. We studied the association between D-dimer levels and clinical and biological characteristics of pregnancies complicated by preeclampsia. RESULTS: D-dimer values increased with increasing gestational age. Patients with HELLP syndrome had mean D-dimer values significantly greater than patients with preeclampsia alone (3848±2551 versus 1578±1077, P<0.001). However, the level of D-dimer at the time of admission was poorly predictive of occurrence of HELLP syndrome. Area under of the ROC curve was 0.69 (CI 95%: 0,59-0,79). The best threshold was 2170 ng/mL with a sensitivity of 0.91 and a specificity of 0.40. Other severity criteria of preeclampsia were not associated with higher levels of D-dimer. DISCUSSION AND CONCLUSION: In preeclamptic patients, D-dimer levels were related with gestational age and HELLP syndrome. However, accuracy of this test to predict occurrence of HELLP syndrome or severe preeclampsia was too low to recommend its use routinely.

[Amniotic fluid embolism suspected in a case of seizure and mild uterine haemorrhage with activation of coagulation and fibrinolysis]. / Embolie amniotique d'évolution favorable suspectée devant un tableau clinique atypique.

After a normal pregnancy and labour in a 29-year-old parturient, a single seizure followed by a transient headache was observed during the uterine revision for placental retention. Mild uterine haemorrhage of 150 ml per hour without any uterine atony was associated with activation of clotting and fibrinolysis (decrease of fibrinogen, elevated fibrin soluble complexes and D-dimers). A ten fold value of foetal blood cells in maternal serum suggested the diagnosis of amniotic fluid embolism. Atypical forms of amniotic fluid embolism and their diagnosis are discussed.

[Coagulation activation with intraportal islets of Langerhans transplantation in swine]. / Activation de la coagulation par la greffe intraportale d'îlots de Langerhans chez le porc.

STUDY AIM: Intraportal islet allograft appears to be one of the promising treatments for type I diabetes. However, many limiting factors persist. An activation of the coagulation cascade upon contact with islets, has been reported recently in vitro and could play a crucial role in a non specific inflammatory reaction and favour the specific immune reaction. The aim of this experimental study was to confirm in vivo this activation of the coagulation cascade. MATERIAL AND METHODS: An allogenic islets preparation or a material control (inert microbeads) was injected intraportally, in Large White pigs (n = 26), associated with or without an anticoagulant treatment (heparin). Systemic markers of haemostasis were measured in pigs for 72 hours following injection of the studied material. RESULTS: The thrombin-antithrombin complex increased and platelet count decreased in groups receiving preparation of islets, both indicators of an activation of the coagulation cascade. This activation was proportional to the injected volume and was partially attenuated by heparin. No activation was observed in pigs receiving the material control. CONCLUSION: The activation of the coagulation cascade and the non specific inflammatory reaction could be one of the obstacles to the success of the islet allografts. The use of anticoagulant and anti-inflammatory molecules could potentially allow an improvement of the present results of islet allograft.

Antithrombin reduces mesenteric venular leukocyte interactions and small intestine injury in endotoxemic rats.

We examined the hypothesis that recombinant human antithrombin would reduce mesenteric venule leukocyte adhesion and small intestine injury in endotoxemic rats. Endotoxemic (endotoxin 10 mg/kg, intravenously) rats were treated either with saline or recombinant human antithrombin (250 and 500 U/kg). In some rats, indomethacin (100 mg/kg, intraperitoneally) was injected 60 min prior to endotoxin and recominant human antithrombin (500 U/kg) treatment. Compared to controls, intravital videomicroscopy of the mesentric venule showed an increase of leukocyte rolling (55+/-17 versus 70+/-19 leukocytes/min; P < 0.05) and firm adhesion (1.1+/-0.3 versus 5.8+/-0.8 leukocytes/100 microm; P < 0.05) in endotoxemic rats. Recombinant human antithrombin attenuated endotoxin-induced venular endothelium leukocyte adhesive cascade. The beneficial effects of recombinant human antithrombin on leukocyte adhesion were inhibited by indomethacin (100 mg/kg, intraperitoneally) in endotoxemic rats. Endotoxin treatment increased fluorescein isothiocyanate (FITC)-labeled dextran 4,000 (FD4) gut lumen to plasma ratio and wet weight/dry weight ratio. Recombinant human antithrombin (500 U/kg) attenuated endotoxin-induced gut injury. These observations suggest that recombinant human antithrombin reduces endothelium-leukocyte interactions in endotoxemic rats by interacting with local prostacyclin production.

Clinical trial results with antithrombin III in sepsis.

OBJECTIVE: To present and discuss the rationale and results of clinical trials using antithrombin (AT) supplementation in patients with sepsis. DATA SOURCES/STUDY SELECTION: Review of all controlled (open or double-blind) studies of patients with severe sepsis or septic shock who were treated with AT concentrates to obtain better control of coagulation activation and inflammation. DATA EXTRACTION: AT is a major inhibitor of the coagulation cascade. Recent experimental studies have also shown that it can modulate the inflammatory reactions that occur during sepsis. An early and prolonged decrease in AT activity is well documented during sepsis-induced disseminated intravascular coagulation and during the systemic inflammatory response. Thus, supplementation with AT concentrates has been proposed as a potential therapy in sepsis patients. DATA SYNTHESIS: Numerous uncontrolled studies of AT supplementation in sepsis patients have been reported in the last 20 yrs. Since 1993, four placebo-controlled randomized studies have been performed in France, Germany, Northwestern Europe, and Italy. Three of these studies were subjected to a meta-analysis of 122 patients. Results showed a nonsignificant 22% reduction in the 30-day all-cause mortality and a reduction in the length of stay in the intensive care unit in the AT treated group. The Italian study of 120 patients demonstrated that the overall mortality was similar in the placebo and treated groups. However, post hoc analysis according to the Cox regression model showed that in patients with septic shock, AT supplementation significantly decreased the risk of death. CONCLUSIONS: Together, these studies are consistent with the positive effect seen with AT supplementation in patients with severe sepsis. A multicenter phase III trial is currently in progress to definitively document its effect on mortality.

Inflammation-induced systemic proteolysis of inter-alpha-inhibitor in plasma from patients with sepsis.

Inter-alpha-inhibitor (IalphaI) is a human plasma serine proteinase inhibitor. It contains one light peptide chain called bikunin that exerts antiproteinase activity and other antiinflammatory functions. Bikunin is covalently linked to two heavy chains that, after tissular diffusion, stabilize the extracellular matrix. Owing to its negative acute-phase reactant character and its susceptibility to proteolysis, IalphaI has been implicated in the pathophysiology of sepsis. Moreover, IalphaI has been shown to exert a protective effect on a pig model of endotoxic shock. Twenty patients admitted to the intensive care unit (ICU) for a septic syndrome were included in the present study. IalphaI and antithrombin III (ATIII) levels were measured on admission. Sequential measurements of IalphaI could be done in 4 patients. We demonstrate that IalphaI levels are significantly decreased in plasma samples collected on admission from patients with sepsis (59 +/- 32 mg/L vs 241 +/- 70 mg/L; P < .0001). This decrease was greater in severe sepsis and septic shock than in sepsis. Death was not predictable from initiol IalphaI levels. In 2 patients with a favorable course, IalphaI values regularly increased during the ICU stay. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by immunoblot analysis and microsequencing, we characterized IalphaI-related components in plasma from several patients; they obviously arise from IalphaI through proteolytic cleavage. Thus, systemic proteolysis and decreased biosynthesis both contribute to the fall in the plasma level of IalphaI. Because IalphaI is very sensitive to proteolysis by polymorphonuclear granulocytes (PMNs) that are stimulated during sepsis, we suggest that IalphaI plasma level would be a useful marker for neutrophil proteinase activity. ATIII, as well as IalphaI, is considered a negative acute phase protein. Because in vitro ATIII is less susceptible than IalphaI to proteolysis by PMNs and because their relative levels weakly correlated, we suggest that an unspecific systemic proteolysis is not significantly involved in the ATIII deficiency occurring in sepsis.

Effects of a combined antithrombin III and protein C supplementation in porcine acute endotoxic shock.

Antithrombin III (ATIII) and protein C (PC) are major inhibitors of the coagulation cascade and might regulate the cytokine network. We tested the possibility that a combined supplementation using these two inhibitors might have synergistic effects on sepsis-induced disseminated intravascular coagulation and shock. Hemodynamics, coagulation parameters, tumor necrosis factor (TNF) alpha, and interleukin 6 levels were measured in pigs submitted to a bolus infusion of Escherichia coli endotoxin (lipopolysaccharide). Four groups were studied: control lipopolysaccharide, ATIII (100 IU/kg), PC (50 IU/kg), and ATIII-PC (same doses). The endotoxin infusion resulted in a typical hypokinetic shock with disseminated intravascular coagulation in all animals. Compared with the control group, a significant improvement in mean arterial pressure and systemic vascular resistance was observed in the PC and ATIII-PC groups. The increase in lactate levels was almost completely blunted in the PC group. A significant lesser increase in TNFalpha levels was observed in the ATIII-PC group. No effects were seen on interleukin 6 levels. Coagulation and fibrinolysis parameters were not improved by ATIII and/or PC, except for a lesser decrease in prothrombin time in the ATIII-PC group. We conclude that in this acute endotoxic model, a combined supplementation using PC and ATIII concentrates has favorable effects on hemodynamic parameters and TNFalpha levels, independently from the anticoagulant actions of these inhibitors.

Effects of inter-alpha-inhibitor in experimental endotoxic shock and disseminated intravascular coagulation.

We investigated the effects of human inter-alpha-inhibitor (I alpha I) on hemodynamics, oxygenation, and coagulation parameters in a porcine model of endotoxic shock. Four groups of six animals were studied: (1) control, (2) I alpha I group receiving 30 mg/kg I alpha I over 30 min, (3) LPS group receiving 5 micrograms.kg/min Escherichia coli endotoxin over 30 min, and (4) LPS + I alpha I group receiving 30 min after endotoxin 30 mg/kg/30 min I alpha I. We measured hemodynamic and oxygenation parameters, usual coagulation markers and plasma levels of thrombin-antithrombin complexes, antithrombin III activity, plasminogen activator tissue type, plasminogen activator inhibitor type 1, von Willebrand factor, tumor necrosis factor-alpha, and I alpha I at baseline and at 30, 60, 90, 120, 180, 240, and 300 min. In the I alpha I group, plasma I alpha I levels reached 447 +/- 23 mg/L just after injection and 287 +/- 39 mg/L at 300 min. I alpha I half-life was 7.3 +/- 1.9 h. In the IPS + I alpha I group, I alpha I plasma levels decreased more rapidly, reaching 260 mg/L at 300 min. Compared with the LPS group, administration of I alpha I normalized the mean arterial pressure and cardiac index, improved the LPS-induced pulmonary hypertension, and resulted in the blunted increase in blood lactate and oxygen extraction ratio. A significant decrease in thrombin-antithrombin complexes and plasminogen activator inhibitor type 1 levels were observed. There was no significant difference in plasma tumor necrosis factor-alpha levels. We concluded that in this hypodynamic model of endotoxin shock, I alpha I administration resulted in a marked improvement in the hemodynamic, oxygenation, and coagulation parameters.

Effects of N omega-nitro-L-arginine methyl ester on the endotoxin-induced disseminated intravascular coagulation in porcine septic shock.

OBJECTIVES: Nitric oxide is known to prevent platelet aggregation and clot formation. Inhibitors of nitric oxide synthase might promote or enhance endotoxin disseminated intravascular coagulation. The present study was designed to evaluate the effects of the arginine analog, N omega-nitro-L-arginine methyl ester (L-NAME), on the endotoxin-induced disseminated intravascular coagulation in a porcine model of septic shock. DESIGN: Prospective, comparative, experimental study. SETTING: Laboratory at a large university hospital. SUBJECTS: Sixteen female piglets, weighing 20 to 28 kg. INTERVENTIONS: Three groups of animals were studied: a control group (n = 6); a lipopolysaccharide (LPS)-treated group (n = 5) receiving Escherichia coli endotoxin (5 micrograms/kg/min over 30 mins); and an LPS + L-NAME group (n = 5) receiving endotoxin and, 1 hr after, a bolus of L-NAME (25 mg/kg). MEASUREMENTS AND MAIN RESULTS: Hemodynamic changes, usual coagulation parameters, and plasma concentrations of thrombin-antithrombin complexes, antithrombin III activity (At III), tissue plasminogen activator, plasminogen activator inhibitor type 1, and von Willebrand factor were measured at baseline, and at 30, 60, 90, 120, 180, 240, and 300 mins. After euthanasia or death, lungs and kidneys were withdrawn for histologic study. The extent of microvascular thrombosis was assessed by a semiquantitative disseminated intravascular coagulation score. In both septic endotoxin group, administration of LPS resulted in hemodynamic changes typical of severe septic shock, with disseminated intravascular coagulation and histologic changes characterized by adult respiratory distress syndrome and kidney microthrombosis. L-NAME administration normalized mean arterial pressure with a dramatic increase in systemic vascular resistances and a marked decrease in cardiac index. The changes in usual coagulation parameters, AT III, tissue plasminogen activator, and plasminogen-activator inhibitor type 1 concentrations were not different between both septic groups. However, in the LPS + L-NAME group, thrombin-antithrombin complexes and von Willebrand factor were higher and associated with a higher histologic disseminated intravascular coagulation score. CONCLUSION: In this model of endotoxin septic shock, L-NAME administration resulted in histologic and coagulation changes consistent with an increased activation of intravascular coagulation.

[Postoperative disorders of hemostasis caused by antifactor V circulating anticoagulant]. / Trouble postopératoire de l'hémostase par anticoagulant circulant anti-facteur V.

The case of a 34-year-old woman who experienced a biological haemostasis disorder, without clinical manifestations, is reported. The disorder was caused by a factor V inhibitor induced by a prolonged administration of antibiotics required by a postoperative biliary peritonitis. Therapeutic strategies in patients with an acquired factor V inhibitor are reviewed.

[Presence and functional role of an epitope of the second receptor for IgE (FcE RII) in mast cells and basophils in the rat]. / Présence et rôle fonctionnel d'un épitope du second récepteur pour l'IgE (FcE RII) sur les mastocytes et les basophiles de rat.

Mast cells and basophils express the high affinity IgE receptor (FcERI) whereas the low affinity receptor for monomeric IgE (FcE RII) is present on macrophages, lymphocytes, eosinophils, platelets and Langerhans cells. Recent studies confirmed that the two receptors were totally distinct. The present work shows that a monoclonal antibody (BB10), able to bind to FcE RII on different cell populations, interacts with FcE RI expressing cells: rat peritoneal mast cells and a rat basophilic leukemia cell line (RBL 2 H 3). The structure recognized by BB10 is distinct from FcE RI and modulates the IgE-dependent histamine release. In conclusion, it appears that a common epitope with FcE RII is present on mast cells and basophils and that a functional relation might exist between this structure and FcE RI.