BACKGROUND

In the Strategies for Management of Anti-Retroviral Therapy trial, all-cause mortality was higher for participants randomized to intermittent, CD4-guided antiretroviral treatment (ART) (drug conservation [DC]) than continuous ART (viral suppression [VS]).We hypothesized that increased HIV-RNA levels following ART interruption induced activation of tissue factor pathways, thrombosis, and fibrinolysis.

RESULTS

Stored samples were used to measure six biomarkers: high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), amyloid A, amyloid P, D-dimer, and <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>. Two studies were conducted: (<em>1</em>) a nested case-control study for studying biomarker associations with mortality, and (<em>2</em>) a study to compare DC and VS participants for biomarker changes. For (<em>1</em>), markers were determined at study entry and before death (latest level) for 85 deaths and for two controls (n = <em>1</em>70) matched on country, age, sex, and date of randomization. Odds ratios (ORs) were estimated with logistic regression. For each biomarker, each of the three upper quartiles was compared to the lowest quartile. For (<em>2</em>), the biomarkers were assessed for <em>2</em>49 DC and <em>2</em>50 VS participants at study entry and <em>1</em> mo following randomization. Higher levels of hsCRP, IL-6, and D-dimer at study entry were significantly associated with an increased risk of all-cause mortality. Unadjusted ORs (highest versus lowest quartile) were <em>2</em>.0 (95% confidence interval [CI], <em>1</em>.0-4.<em>1</em>; p = 0.05), 8.3 (95% CI, 3.3-<em>2</em>0.8; p < 0.000<em>1</em>), and <em>1</em><em>2</em>.4 (95% CI, 4.<em>2</em>-37.0; p < 0.000<em>1</em>), respectively. Associations were significant after adjustment, when the DC and VS groups were analyzed separately, and when latest levels were assessed. IL-6 and D-dimer increased at <em>1</em> mo by 30% and <em>1</em>6% in the DC group and by 0% and 5% in the VS group (p < 0.000<em>1</em> for treatment difference for both biomarkers); increases in the DC group were related to HIV-RNA levels at <em>1</em> mo (p < 0.000<em>1</em>). In an expanded case-control analysis (four controls per case), the OR (DC/VS) for mortality was reduced from <em>1</em>.8 (95% CI, <em>1</em>.<em>1</em>-3.<em>1</em>; p = 0.0<em>2</em>) to <em>1</em>.5 (95% CI, 0.8-<em>2</em>.8) and <em>1</em>.4 (95% CI, 0.8-<em>2</em>.5) after adjustment for latest levels of IL-6 and D-dimer, respectively.

CONCLUSIONS

IL-6 and D-dimer were strongly related to all-cause mortality. Interrupting ART may further increase the risk of death by raising IL-6 and D-dimer levels. Therapies that reduce the inflammatory response to HIV and decrease IL-6 and D-dimer levels may warrant investigation.

OBJECTIVE

Coagulopathy following major trauma is conventionally attributed to activation and consumption of coagulation factors. Recent studies have identified an acute coagulopathy present on admission that is independent of injury severity. We hypothesized that early coagulopathy is due to tissue hypoperfusion, and investigated derangements in coagulation associated with this.

METHODS

This was a prospective cohort study of major trauma patients admitted to a single trauma center. Blood was drawn within <em>1</em>0 minutes of arrival for analysis of partial thromboplastin and <em>prothrombin</em> times, <em>prothrombin</em> <em>fragments</em> <em>1</em>+<em>2</em>, fibrinogen, thrombomodulin, protein C, plasminogen activator inhibitor-<em>1</em>, and D-dimers. Base deficit (BD) was used as a measure of tissue hypoperfusion.

RESULTS

A total of <em>2</em>08 patients were enrolled. Patients without tissue hypoperfusion were not coagulopathic, irrespective of the amount of thrombin generated. Prolongation of the partial thromboplastin and <em>prothrombin</em> times was only observed with an increased BD. An increasing BD was associated with high soluble thrombomodulin and low protein C levels. Low protein C levels were associated with prolongation of the partial thromboplastin and <em>prothrombin</em> times and hyperfibrinolysis with low levels of plasminogen activator inhibitor-<em>1</em> and high D-dimer levels. High thrombomodulin and low protein C levels were significantly associated with increased mortality, blood transfusion requirements, acute renal injury, and reduced ventilator-free days.

CONCLUSIONS

Early traumatic coagulopathy occurs only in the presence of tissue hypoperfusion and appears to occur without significant consumption of coagulation factors. Alterations in the thrombomodulin-protein C pathway are consistent with activated protein C activation and systemic anticoagulation. Admission plasma thrombomodulin and protein C levels are predictive of clinical outcomes following major trauma.

BACKGROUND

Bleeding is a complication of treatment with factor Xa inhibitors, but there are no specific agents for the reversal of the effects of these drugs. Andexanet is designed to reverse the anticoagulant effects of factor Xa inhibitors.

METHODS

Healthy older volunteers were given 5 mg of apixaban twice daily or <em>2</em>0 mg of rivaroxaban daily. For each factor Xa inhibitor, a two-part randomized placebo-controlled study was conducted to evaluate andexanet administered as a bolus or as a bolus plus a <em>2</em>-hour infusion. The primary outcome was the mean percent change in anti-factor Xa activity, which is a measure of factor Xa inhibition by the anticoagulant.

RESULTS

Among the apixaban-treated participants, anti-factor Xa activity was reduced by 94% among those who received an andexanet bolus (<em>2</em>4 participants), as compared with <em>2</em>1% among those who received placebo (9 participants) (P<0.001), and unbound apixaban concentration was reduced by 9.3 ng per milliliter versus 1.9 ng per milliliter (P<0.001); thrombin generation was fully restored in 100% versus 11% of the participants (P<0.001) within <em>2</em> to 5 minutes. Among the rivaroxaban-treated participants, anti-factor Xa activity was reduced by 9<em>2</em>% among those who received an andexanet bolus (<em>2</em>7 participants), as compared with 18% among those who received placebo (14 participants) (P<0.001), and unbound rivaroxaban concentration was reduced by <em>2</em>3.4 ng per milliliter versus 4.<em>2</em> ng per milliliter (P<0.001); thrombin generation was fully restored in 96% versus 7% of the participants (P<0.001). These effects were sustained when andexanet was administered as a bolus plus an infusion. In a subgroup of participants, transient increases in levels of d-dimer and prothrombin fragments 1 and <em>2</em> were observed, which resolved within <em>2</em>4 to 7<em>2</em> hours. No serious adverse or thrombotic events were reported.

CONCLUSIONS

Andexanet reversed the anticoagulant activity of apixaban and rivaroxaban in older healthy participants within minutes after administration and for the duration of infusion, without evidence of clinical toxic effects. (Funded by Portola Pharmaceuticals and others; ANNEXA-A and ANNEXA-R ClinicalTrials.gov numbers, NCT0<em>2</em><em>2</em>077<em>2</em>5 and NCT0<em>2</em><em>2</em><em>2</em>07<em>2</em>5.).

BACKGROUND

Coagulopathy is present at admission in <em>2</em>5% of trauma patients, is associated with shock and a 5-fold increase in mortality. The coagulopathy has recently been associated with systemic activation of the protein C pathway. This study was designed to characterize the thrombotic, coagulant and fibrinolytic derangements of trauma-induced shock.

METHODS

This was a prospective cohort study of major trauma patients admitted to a single trauma center. Blood was drawn within <em>1</em>0 minutes of arrival for analysis of partial thromboplastin and <em>prothrombin</em> times, <em>prothrombin</em> <em>fragments</em> <em>1</em> + <em>2</em> (PF<em>1</em> + <em>2</em>), fibrinogen, factor VII, thrombomodulin, protein C, plasminogen activator inhibitor-<em>1</em> (PAI-<em>1</em>), thrombin activatable fibrinolysis inhibitor (TAFI), tissue plasminogen activator (tPA), and D-dimers. Base deficit was used as a measure of tissue hypoperfusion.

RESULTS

Two hundred eight patients were studied. Systemic hypoperfusion was associated with anticoagulation and hyperfibrinolysis. Coagulation was activated and thrombin generation was related to injury severity, but acidosis did not affect Factor VII or PF<em>1</em> + <em>2</em> levels. Hypoperfusion-induced increase in soluble thrombomodulin levels was associated with reduced fibrinogen utilization, reduction in protein C and an increase in TAFI. Hypoperfusion also resulted in hyperfibrinolysis, with raised tPA and D-Dimers, associated with the observed reduction in PAI-<em>1</em> and not alterations in TAFI.

CONCLUSIONS

Acute coagulopathy of trauma is associated with systemic hypoperfusion and is characterized by anticoagulation and hyperfibrinolysis. There was no evidence of coagulation factor loss or dysfunction at this time point. Soluble thrombomodulin levels correlate with thrombomodulin activity. Thrombin binding to thrombomodulin contributes to hyperfibrinolysis via activated protein C consumption of PAI-<em>1</em>.

Eighty percent of patients with diabetes mellitus die a thrombotic death. Seventy-five percent of these deaths is due to cardiovascular complications, and the remainder is due to cerebrovascular events and peripheral vascular complications. Vascular endothelium, the primary defense against thrombosis, is abnormal in diabetes. Endothelial abnormalities undoubtedly play a role in the enhanced activation of platelets and clotting factors seen in diabetes. Coagulation activation markers, such as <em>prothrombin</em> activation <em>fragment</em> <em>1</em>+<em>2</em> and thrombin-anti-thrombin complexes, are elevated in diabetes. The plasma levels of many clotting factors including fibrinogen, factor VII, factor VIII, factor XI, factor XII, kallikrein, and von Willebrand factor are elevated in diabetes. Conversely, the level of the anticoagulant protein C (PC) is decreased. The fibrinolytic system, the primary means of removing clots, is relatively inhibited in diabetes due to abnormal clot structures that are more resistant to degradation and an increase in plasminogen activator inhibitor type <em>1</em> (PAI-<em>1</em>). Increased circulating platelet aggregates, increased platelet aggregation in response to platelet agonists, increased platelet contractile force (PCF), and the presence of higher plasma levels of platelet release products, such as beta-thromboglobulin, platelet factor 4, and thromboxane B(<em>2</em>), demonstrate platelet hyperactivity in diabetes. This constellation of findings supports the clinical observation that diabetes is a hypercoagulable state. This article briefly reviews the published evidence for this conclusion and the putative roles played by hyperglycemia and hyperinsulinemia in its development.

Patients with meningococcal sepsis generally suffer from disseminated intravascular coagulation (DIC). The aim of this study was to address whether these patients have elevated numbers of circulating microparticles that contribute to the development of DIC. Plasma samples from 5 survivors, <em>2</em> nonsurvivors, and 5 healthy volunteers were analyzed for the presence of microparticles by flow cytometry. Ongoing coagulation activation in vivo was quantified by enzyme-linked immunosorbent assay of plasma <em>prothrombin</em> <em>fragment</em> F(<em>1</em> + <em>2</em>), and procoagulant properties of microparticles in vitro were estimated by thrombin-generation assay. On admission, all patients had increased numbers of microparticles originating from platelets or granulocytes when compared with controls (P =.004 and P =.008, respectively). Patients had elevated levels of F(<em>1</em> + <em>2</em>) (P =.004), and their microparticles supported thrombin generation more strongly in vitro (P =.003) than those of controls. Plasma from the patient with the most fulminant disease course and severe DIC contained microparticles that expressed both CD<em>1</em>4 and tissue factor, and these microparticles demonstrated extreme thrombin generation in vitro. We conclude that patients with meningococcal sepsis have elevated numbers of circulating microparticles that are procoagulant. These findings may suggest a novel therapeutic approach to combat clinical conditions with excessive coagulation activation.

OBJECTIVE

Full length keratin-<em>1</em>8 (FL-K<em>1</em>8) and High Mobility Group Box-<em>1</em> (HMGB<em>1</em>) represent circulating indicators of necrosis during acetaminophen (APAP) hepatotoxicity in vivo. In addition, the caspase-cleaved <em>fragment</em> of K<em>1</em>8 (cK<em>1</em>8) and hyper-acetylated HMGB<em>1</em> represent serum indicators of apoptosis and immune cell activation, respectively. The study aim was to assess their mechanistic utility to establish the balance between apoptosis, necrosis, and immune cell activation throughout the time course of clinical APAP hepatotoxicity.

METHODS

HMGB<em>1</em> (total, acetylated) and K<em>1</em>8 (apoptotic, necrotic) were identified and quantified by novel LC-MS/MS assays in APAP overdose patients (n=78).

RESULTS

HMGB<em>1</em> (total; <em>1</em>5.4±<em>1</em>.9ng/ml, p<0.0<em>1</em>, acetylated; 5.4±2.6ng/ml, p<0.00<em>1</em>), cK<em>1</em>8 (5649.8±72<em>1</em>.0U/L, p<0.0<em>1</em>), and FL-K<em>1</em>8 (54770.2±67<em>1</em>7.0U/L, p<0.005) were elevated in the sera of APAP overdose patients with liver injury compared to overdose patients without liver injury and healthy volunteers. HMGB<em>1</em> and FL-K<em>1</em>8 correlated with alanine aminotransferase (ALT) activity (R(2)=0.60 and 0.58, respectively, p<0.000<em>1</em>) and prothrombin time (R(2)=0.62 and 0.7<em>1</em>, respectively, p<0.000<em>1</em>). Increased total and acetylated HMGB<em>1</em> and FL-K<em>1</em>8 were associated with worse prognosis (King's College Criteria) or patients that died/required liver transplant compared to spontaneous survivors (all p<0.05-0.00<em>1</em>), a finding not reflected by ALT and supported by ROC analysis. Acetylated HMGB<em>1</em> was a better predictor of outcome than the other markers of cell death.

CONCLUSIONS

K<em>1</em>8 and HMGB<em>1</em> represent blood-based tools to investigate the cell death balance clinical APAP hepatotoxicity. Activation of the immune response was seen later in the time course as shown by the distinct profile of acetylated HMGB<em>1</em> and was associated with worse outcome.

Hyperglycemia is associated with increased susceptibility to atherothrombotic stimuli. The glycocalyx, a layer of proteoglycans covering the endothelium, is involved in the protective capacity of the vessel wall. We therefore evaluated whether hyperglycemia affects the glycocalyx, thereby increasing vascular vulnerability. The systemic glycocalyx volume was estimated by comparing the distribution volume of a glycocalyx permeable tracer (dextran 40) with that of a glycocalyx impermeable tracer (labeled erythrocytes) in <em>1</em>0 healthy male subjects. Measurements were performed in random order on five occasions: two control measurements, two measurements during normoinsulinemic hyperglycemia with or without N-acetylcysteine (NAC) infusion, and one during mannitol infusion. Glycocalyx measurements were reproducible (<em>1</em>.7 +/- 0.<em>2</em> vs. <em>1</em>.7 +/- 0.3 l). Hyperglycemia reduced glycocalyx volume (to 0.8 +/- 0.<em>2</em> l; P < 0.05), and NAC was able to prevent the reduction (<em>1</em>.4 +/- 0.<em>2</em> l). Mannitol infusion had no effect on glycocalyx volume (<em>1</em>.6 +/- 0.<em>1</em> l). Hyperglycemia resulted in endothelial dysfunction, increased plasma hyaluronan levels (from 70 +/- 6 to <em>1</em><em>1</em><em>2</em> +/- <em>1</em>6 ng/ml; P < 0.05) and coagulation activation (<em>prothrombin</em> activation <em>fragment</em> <em>1</em> + <em>2</em>: from 0.4 +/- 0.<em>1</em> to <em>1</em>.<em>1</em> +/- 0.<em>2</em> nmol/l; d-dimer: from 0.<em>2</em>7 +/- 0.<em>1</em> to 0.55 +/- 0.<em>2</em> g/l; P < 0.05). Taken together, these data indicate a potential role for glycocalyx perturbation in mediating vascular dysfunction during hyperglycemia.

BACKGROUND

High mobility group box nuclear protein <em>1</em> (HMGB<em>1</em>) is a DNA nuclear binding protein that has recently been shown to be an early trigger of sterile inflammation in animal models of trauma-hemorrhage via the activation of the Toll-like-receptor 4 (TLR4) and the receptor for the advanced glycation endproducts (RAGE). However, whether HMGB<em>1</em> is released early after trauma hemorrhage in humans and is associated with the development of an inflammatory response and coagulopathy is not known and therefore constitutes the aim of the present study.

METHODS

One hundred sixty eight patients were studied as part of a prospective cohort study of severe trauma patients admitted to a single Level <em>1</em> Trauma center. Blood was drawn within <em>1</em>0 minutes of arrival to the emergency room before the administration of any fluid resuscitation. HMGB<em>1</em>, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, von Willebrand Factor (vWF), angiopoietin-<em>2</em> (Ang-<em>2</em>), Prothrombin time (PT), <em>prothrombin</em> <em>fragments</em> <em>1</em>+<em>2</em> (PF<em>1</em>+<em>2</em>), soluble thrombomodulin (sTM), protein C (PC), plasminogen activator inhibitor-<em>1</em> (PAI-<em>1</em>), tissue plasminogen activator (tPA) and D-Dimers were measured using standard techniques. Base deficit was used as a measure of tissue hypoperfusion. Measurements were compared to outcome measures obtained from the electronic medical record and trauma registry.

RESULTS

Plasma levels of HMGB<em>1</em> were increased within 30 minutes after severe trauma in humans and correlated with the severity of injury, tissue hypoperfusion, early posttraumatic coagulopathy and hyperfibrinolysis as well with a systemic inflammatory response and activation of complement. Non-survivors had significantly higher plasma levels of HMGB<em>1</em> than survivors. Finally, patients who later developed organ injury, (acute lung injury and acute renal failure) had also significantly higher plasma levels of HMGB<em>1</em> early after trauma.

CONCLUSIONS

The results of this study demonstrate for the first time that HMGB<em>1</em> is released into the bloodstream early after severe trauma in humans. The release of HMGB<em>1</em> requires severe injury and tissue hypoperfusion, and is associated with posttraumatic coagulation abnormalities, activation of complement and severe systemic inflammatory response.

Human alpha-thrombin, the thromboplastin activation product of <em>prothrombin</em> with high clotting and esterase activity, was produced from Cohn Fraction III paste. The procedure started with 0.4 to 3.<em>2</em> kg of frozen paste and was completed in <em>2</em> or 3 days. Some <em>2</em>3 g of thrombin were recorded for 65 quantitated preparations made from <em>1</em><em>1</em> lots of Fraction III paste. These preparations were obtained at protein concentrations of 3.9 +/- <em>1</em>.3 mg/ml with a yield of 340 +/- <em>1</em><em>1</em>0 mg/kg of paste, which represented 48 +/- <em>1</em>4% of the clotting potential extracted as <em>prothrombin</em>. They had specific clotting activities of <em>2</em>.8 +/- 0.4 U.S. (NIH) units/microng of protein and titrated to 88 +/- 8% active with p-nitrophenyl-p'-guanidinobenzoate (NPGB). Those (N - <em>2</em>9) examined by labeling with [<em>1</em>4C]diisopropyl phosphorofluoridate (iPr<em>2</em>P-F) and electrophoresing in sodium dodecyl sulfate (SDS)-polyacrylamide gels were found to contain only (N = 4) or predominantly alpha-thrombin (97 +/- 3%) and corresponding amounts of ists degradation product, beta-thrombin (<em>2</em>.6 +/- 3.<em>1</em>%). No plasmin(ogen), <em>prothrombin</em> complex factors (II, VII, IX, IXalpha, X, Xalpha), or <em>prothrombin</em> <em>fragments</em> were detected in representative preparations. As produced in 0.75 M NaCl, pH approximately 6, thrombin was stable for approximately <em>1</em> week at 4 degrees and for greater than <em>1</em> year at less than or equal to 50 degrees; freeze-dried thrombin stored at 4 degrees for greater than <em>1</em> year displayed stable clotting activity and no vial to vial variation, permitting its use for reference purposes. Human thrombin generated by Taipan snake venom activation was compared with that produced by rapid thromboplastin activation: after treatment with [<em>1</em>4C]iPr<em>2</em>P-F, greater than 95% of the label in both thrombins migrated at the same rate during electrophoresis in SDS; identical pairs of NH<em>2</em>-terminal residues were released in three consecutive Edman degradation cycles.

Urine contains compounds that modulate the nucleation, growth and aggregation of crystals as well as their attachment to renal epithelial cells. These compounds may function to protect the kidneys against: <em>1</em>, the possibility of crystallization in tubular fluid and urine, which are generally metastable with respect to calcium salts, <em>2</em>, crystal retention within the kidneys thereby preventing stone formation and 3, possibly against plaque formation at the nephron basement membrane. Since oxalate is the most common stone type, the effect of various modulators on calcium oxalate (CaOx) crystallization has been examined in greater details. Most of the inhibitory activity resides in macromolecules such as glycoproteins and glycosaminoglycans while nucleation promotion activity is most likely sustained by membrane lipids. Nephrocalcin, Tamm-Horsfall protein, osteopontin, urinary <em>prothrombin</em> <em>fragment</em> <em>1</em>, and bikunin are the most studied inhibitory proteins while chondroitin sulfate (CS), heparan sulfate (HS) and hyaluronic acid (HA) are the best studied glycosaminoglycans. Crystallization modulating macromolecules discussed here are also prominent in cell injury, inflammation and recovery. Renal epithelial cells on exposure to oxalate and CaOx crystals produce some of the inflammatory molecules such as monocyte chemoattractant protein-<em>1</em> (MCP-<em>1</em>) with no apparent role in crystal formation. In addition, macrophages surround the CaOx crystals present in the renal interstitium. These observations indicate a close relationship between inflammation and nephrolithiasis.

Highly purified human thrombin stimulates the adherence of polymorphonuclear leukocytes (PMNs) to vascular endothelial cells (EC). When Indium-labeled PMNs were incubated with primary monolayers of cultured human umbilical vein EC, the basal adherence was <em>1</em>0 +/- <em>1</em>% of the PMNs at 5 min. Addition of thrombin (<em>2</em> U/ml) increased the mean adherence to 4<em>2</em> +/- <em>1</em>5%. Enhanced neutrophil adherence in response to thrombin was confirmed by experiments with unlabeled leukocytes, examined by phase contrast and scanning electron microscopy. The action of thrombin was on the EC, since it did not directly stimulate PMN adhesiveness when measured by aggregation or by adherence to nylon fiber columns. Furthermore, enhanced neutrophil adherence occurred when endothelial monolayers were treated with thrombin and washed before adding <em>1</em><em>1</em><em>1</em>Indium (<em>1</em><em>1</em><em>1</em>In)-labeled PMNs. Thrombin that had been inactivated with antithrombin III and heparin did not enhance neutrophil adherence. <em>Prothrombin</em>, Factor Xa, and fibrinogen were also ineffective. The stimulated adherence of PMNs was maximal 5 min after incubation of the EC with thrombin, and decreased thereafter. The response was dose-dependent, with half-maximal stimulation at 0.<em>2</em>-0.<em>2</em>5 U thrombin/ml. The enhanced PMN adherence caused by thrombin may result in part from the production of platelet-activating factor (PAF) by the stimulated EC since thrombin-stimulated EC synthesize PAF with a time course and concentration dependence that are similar to the time and concentration relationships for thrombin-stimulated PMN adherence, PAF itself promoted neutrophil adherence to the EC monolayers, and pretreatment of PMNs with PAF decreased the adherence stimulated by thrombin and PAF, but not adherence stimulated by N-formylmethionyl-leucyl-phenylalanine and C5a <em>fragments</em>, which indicates specific desensitization of PAF-mediated adherence. These studies demonstrate the endothelial cell-dependent stimulation of PMN adherence by thrombin, a novel mechanism of enhanced leukocyte adherence that may be important in interactions between the coagulation and inflammatory systems.

BACKGROUND

Type <em>2</em> diabetes is associated with accelerated atherosclerosis. Because cell-derived microparticles support coagulation and inflammation, they may be involved in atherogenesis. We characterized circulating microparticles both in patients with uncomplicated, well-regulated type <em>2</em> diabetes and in healthy subjects, as well as their relationship with coagulation and metabolic control.

RESULTS

Microparticles were isolated from plasma, stained with annexin V, cell-specific monoclonal antibodies (MoAbs) and a MoAb directed against tissue factor (TF), and analyzed by flow cytometry. Microparticle numbers and origin were comparable in the two groups, but the median number of TF-positive microparticles was twice as high in patients than in controls (P=0.018). Patients had higher percentages of TF-positive microparticles from T-helper cells (P=0.045), granulocytes (P=0.004), and platelets (P=0.00<em>2</em>). Subpopulations of TF-positive microparticles from platelets and T-helper cells exposed granulocytic markers. Correlations were found between the numbers of various TF-positive microparticle subpopulations and body mass index, fasting plasma glucose and insulin, or tumor necrosis factor-alpha and serum HDL cholesterol. Microparticles from patients generated less thrombin in vitro (P=0.007). Microparticle numbers did not correlate with in vivo coagulation markers prothrombin fragment F(1+<em>2</em>) and thrombin-antithrombin complexes.

CONCLUSIONS

TF, possibly of granulocytic origin, is exposed on microparticle subpopulations in asymptomatic patients with well-regulated type <em>2</em> diabetes. TF-positive microparticles are associated with components of the metabolic syndrome but not with coagulation. Thus, TF on microparticles may be involved in processes other than coagulation, including transcellular signaling or angiogenesis.

BACKGROUND

Activation and coagulation biomarkers were measured within the Strategies for Management of Antiretroviral Therapy (SMART) trial. Their associations with opportunistic disease (OD) in human immunodeficiency virus (HIV)-positive patients were examined.

METHODS

Inflammatory (high-sensitivity C-reactive protein [hsCRP], interleukin-6 [IL-6], amyloid-A, and amyloid-P) and coagulation (D-dimer and <em>prothrombin</em>-<em>fragment</em> <em>1</em>+<em>2</em>) markers were determined. Conditional logistic regression analyses were used to assess associations between these biomarkers and risk of OD.

RESULTS

The 9<em>1</em> patients who developed an OD were matched to <em>1</em>8<em>2</em> control subjects. Patients with an hsCRP level>> or =5 microg/mL at baseline had a 3.5 higher odds of OD (95% confidence interval [CI], <em>1</em>.5-8.<em>1</em>) than did those with an hsCRP level (<em>1</em> microg/mL (P=.003, by test for trend) and patients with an IL-6 level>> or =3 pg/mL at baseline had a <em>2</em>.4 higher odds of OD (95% CI, <em>1</em>.0-5.4) than did those with an IL-6 level (<em>1</em>.5 pg/mL (P=.0<em>2</em>, by test for trend). No other baseline biomarkers predicted development of an OD. Latest follow-up hsCRP level for those with an hsCRP level>> or =5 microg/mL (compared with a level (<em>1</em> microg/mL; odds ratio [OR], 7.6; 95% CI, <em>2</em>.0-<em>2</em>8.5; [P=.00<em>2</em>, by test for trend), latest amyloid-A level for those with an amyloid-A level>> or =6 mg/L (compared with a level (<em>2</em> mg/L; OR, 3.8; 95% CI, <em>1</em>.<em>1</em>-<em>1</em>3.4; P=.03, by test for trend), and latest IL-6 level for those with an IL-6 level>> or =3 pg/mL (compared with a level (<em>1</em>.5 pg/mL; OR <em>2</em>.4; 95% CI, 0.7-8.8; P=.04, by test for trend) were also associated with development of an OD.

CONCLUSIONS

Higher IL-6 and hsCRP levels independently predicted development of OD. These biomarkers could provide additional prognostic information for predicting the risk of OD.

BACKGROUND

Raloxifene is a selective estrogen receptor modulator that has estrogen-agonistic effects on bone and estrogen-antagonistic effects on breast and uterus.

OBJECTIVE

To identify the effects of raloxifene on markers of cardiovascular risk in postmenopausal women, and to compare them with those induced by hormone replacement therapy (HRT).

METHODS

Double-blind, randomized, parallel trial.

METHODS

Eight sites in the United States.

METHODS

390 healthy postmenopausal women recruited by advertisement.

METHODS

Participants were randomized to receive <em>1</em> of 4 treatments: raloxifene, 60 mg/d; raloxifene, <em>1</em>20 mg/d; HRT (conjugated equine estrogen, 0.625 mg/d, and medroxyprogesterone acetate, 2.5 mg/d); or placebo.

METHODS

Change and percent change from baseline of lipid levels and coagulation parameters after 3 months and 6 months of treatment.

RESULTS

At the last visit completed, compared with placebo, both dosages of raloxifene significantly lowered low-density lipoprotein cholesterol (LDL-C) by <em>1</em>2% (P < .00<em>1</em>), similar to the <em>1</em>4% reduction with HRT (P < .00<em>1</em>). Both dosages of raloxifene significantly lowered lipoprotein(a) by 7% to 8% (P < .00<em>1</em>), less than the <em>1</em>9% decrease with HRT (P<.00<em>1</em>). Raloxifene increased high-density lipoprotein-2 cholesterol (HDL2-C) by <em>1</em>5% to <em>1</em>7% (P < .05), less than the 33% increase with HRT (P < .00<em>1</em>). Raloxifene did not significantly change high-density lipoprotein cholesterol (HDL-C), triglycerides, or plasminogen activator inhibitor-<em>1</em> (PAI-<em>1</em>); whereas HRT increased HDL-C by <em>1</em><em>1</em>% and triglycerides by 20%, and decreased PAI-<em>1</em> by 29% (for all, P < .00<em>1</em>). Raloxifene significantly lowered fibrinogen by <em>1</em>2% to <em>1</em>4% (P < .00<em>1</em>), unlike HRT, which had no effect. Neither treatment changed fibrinopeptide A or prothrombin fragment <em>1</em> and 2.

CONCLUSIONS

Raloxifene favorably alters biochemical markers of cardiovascular risk by decreasing LDL-C, fibrinogen, and lipoprotein(a), and by increasing HDL2-C without raising triglycerides. In contrast to HRT, raloxifene had no effect on HDL-C and PAI-<em>1</em>, and a lesser effect on HDL2-C and lipoprotein(a). Further clinical trials are necessary to determine whether these favorable biochemical effects are associated with protection against cardiovascular disease.

OBJECTIVE

Venous thromboembolism (VTE) is a well-recognized complication of cancer. Laboratory parameters might be useful to assess the VTE risk in patients with cancer. The aim of this study was to investigate D-dimer and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F <em>1</em> + <em>2</em>), which reflect activation of blood coagulation and fibrinolysis, for prediction of cancer-associated VTE.

METHODS

In a prospective, observational, cohort study of 8<em>2</em><em>1</em> patients with newly diagnosed cancer or progression of disease who did not recently receive chemotherapy, radiotherapy, or surgery were enrolled and followed for a median of 50<em>1</em> days (interquartile range, <em>2</em>55 to 73<em>1</em> days). The malignancies in these patients were as follows: breast (n = <em>1</em>3<em>2</em>), lung (n = <em>1</em><em>1</em>9), stomach (n = 35), lower gastrointestinal tract (n = <em>1</em>06), pancreas (n = 46), kidney (n = <em>2</em><em>2</em>), and prostate (n = <em>1</em>0<em>1</em>) cancers; high-grade glioma (n = <em>1</em>0<em>2</em>); malignant lymphoma (n = 94); multiple myeloma (n = <em>1</em>7); and other tumor types (n = 47). The study end point was occurrence of objectively confirmed symptomatic or fatal VTE.

RESULTS

VTE occurred in 6<em>2</em> patients (7.6%). The cutoff level for elevated D-dimer and elevated F <em>1</em> + <em>2</em> was set at the 75th percentile of the total study population. In multivariable analysis that included elevated D-dimer, elevated F <em>1</em> + <em>2</em>, age, sex, surgery, chemotherapy, and radiotherapy, the hazard ratios (HRs) of VTE in patients with elevated D-dimer (HR, <em>1</em>.8; 95% CI, <em>1</em>.0 to 3.<em>2</em>; P = .048) and elevated F <em>1</em> + <em>2</em> (HR, <em>2</em>.0; 95% CI, <em>1</em>.<em>2</em> to 3.6; P = .0<em>1</em>5) were statistically significantly increased. The cumulative probability of developing VTE after 6 months was highest in patients with both elevated D-dimer and elevated F <em>1</em> + <em>2</em> (<em>1</em>5.<em>2</em>%) compared with patients with nonelevated D-dimer and nonelevated F <em>1</em> + <em>2</em> (5.0%; P < .00<em>1</em>).

CONCLUSIONS

High D-dimer and F <em>1</em> + <em>2</em> levels independently predict occurrence of VTE in patients with cancer.

OBJECTIVE

To determine the cellular origin of synovial microparticles, their procoagulant properties, and their relationship to local hypercoagulation.

METHODS

Microparticles in synovial fluid and plasma from patients with rheumatoid arthritis (RA; n = <em>1</em>0) and patients with other forms of arthritis (non-RA; n = <em>1</em>0) and in plasma from healthy subjects (n = <em>2</em>0) were isolated by centrifugation. Microparticles were identified by flow cytometry. The ability of microparticles to support coagulation was determined in normal plasma. Concentrations of <em>prothrombin</em> <em>fragment</em> F(<em>1</em>+<em>2</em>) (by enzyme-linked immunosorbent assay [ELISA]) and thrombin-antithrombin (TAT) complexes (by ELISA) were determined as estimates of the coagulation activation status in vivo.

RESULTS

Plasma from patients and healthy controls contained comparable numbers of microparticles, which originated from platelets and erythrocytes. Synovial microparticles from RA patients and non-RA patients originated mainly from monocytes and granulocytes; few originated from platelets and erythrocytes. Synovial microparticles bound less annexin V (which binds to negatively charged phospholipids) than did plasma microparticles, exposed tissue factor, and supported thrombin generation via factor VII. F(<em>1</em>+<em>2</em>) (median 66 nM) and TAT complex (median 7<em>1</em>0 microg/liter) concentrations were elevated in synovial fluid compared with plasma from the patients (<em>1</em>.6 nM and 7.0 microg/liter, respectively) as well as the controls (<em>1</em>.0 nM and <em>2</em>.9 microg/liter, respectively).

CONCLUSIONS

Synovial fluid contains high numbers of microparticles derived from leukocytes that are strongly coagulant via the factor VII-dependent pathway. We propose that these microparticles contribute to the local hypercoagulation and fibrin deposition in inflamed joints of patients with RA and other arthritic disorders.

BACKGROUND

The blood coagulation system is activated in the acute phase of unstable angina and acute myocardial infarction. However, it remains unclear whether augmented function of the hemostatic mechanism serves only as a marker of the acute thrombotic episode or whether a hypercoagulable state persists for a prolonged period after clinical stabilization.

RESULTS

We prospectively measured the plasma concentrations of <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>) and fibrinopeptide A (FPA) in consecutive patients presenting with unstable angina (n = 8<em>1</em>) or acute myocardial infarction (n = 3<em>2</em>), respectively. At 6 months, plasma determinations were repeated in patients experiencing an uneventful clinical course (unstable angina, n = 57; myocardial infarction, n = <em>2</em>3). We quantitated the plasma levels of F<em>1</em> + <em>2</em> and FPA in control patients with stable angina (n = 37) or healthy individuals (n = 3<em>2</em>) who were matched for age and sex. The median plasma concentrations of F<em>1</em> + <em>2</em> and FPA are significantly higher in patients presenting with unstable angina (F<em>1</em> + <em>2</em>, <em>1</em>.08 nmol/L; FPA, <em>2</em>.4 nmol/L) or acute myocardial infarction (F<em>1</em> + <em>2</em>, <em>1</em>.<em>2</em>7 nmol/L; FPA, 3.55 nmol/L) compared with patients with stable angina (F<em>1</em> + <em>2</em>, 0.74 nmol/L; FPA, <em>1</em>.3 nmol/L; P < .000<em>1</em>) or healthy individuals (F<em>1</em> + <em>2</em>, 0.7<em>1</em> nmol/L; FPA, 0.80 nmol/L; P < .000<em>1</em>). At 6 months, the median plasma levels of F<em>1</em> + <em>2</em> in patients exhibiting an uneventful clinical course did not differ from values obtained at admission (unstable angina, <em>1</em>.<em>2</em>6 versus <em>1</em>.07 nmol/L, P = NS; myocardial infarction, <em>1</em>.<em>2</em><em>2</em> versus <em>1</em>.<em>2</em>9 nmol/L, P = NS), whereas the median plasma levels of FPA in the same two subpopulations were significantly reduced (unstable angina, <em>1</em>.<em>1</em> versus <em>2</em>.9 nmol/L, P = .0003; myocardial infarction, <em>1</em>.<em>1</em> versus 3.0 nmol/L; P = .00<em>2</em>8).

CONCLUSIONS

During the acute phase of unstable angina and myocardial infarction, patients exhibit increased coagulation system activity. Over the next 6 months, patients with unstable angina or myocardial infarction experiencing an uneventful clinical course manifest a persistent hypercoagulable state with minimal generation of fibrin.

The role of interleukin 6 (IL-6) in the toxic sequelae of sepsis is controversial. To assess the part of IL-6 in inflammatory responses to endotoxin, we investigated eight chimpanzees after either a bolus intravenous injection of Escherichia coli endotoxin (n = 4; 4 ng/kg) or after the same dose of endotoxin with a simultaneous bolus intravenous injection of an anti-IL-6 mAb (30 mg; n = 4). Anti-IL-6 did not affect the induction of the cytokine network (tumor necrosis factor [TNF], soluble TNF receptors types I and II, and IL-8) by endotoxin, nor did it influence the occurrence of a neutrophilic leukocytosis and neutrophil degranulation, as monitored by the measurement of elastase-alpha <em>1</em>-antitrypsin complexes. In contrast, anti-IL-6 markedly attenuated endotoxin-induced activation of coagulation, monitored with the plasma levels of the <em>prothrombin</em> <em>fragment</em> F<em>1</em>+<em>2</em> and thrombin-antithrombin III complexes, whereas activation of fibrinolysis, determined with the plasma concentrations of plasmin-alpha <em>2</em>-antiplasmin complexes, remained unaltered. We conclude that IL-6 does not have a feedback effect on the release of other cytokines after injection of endotoxin, and that it is not involved in endotoxin-induced neutrophilia or neutrophil degranulation. IL-6 is, however, an important intermediate factor in activation of coagulation in low grade endotoxemia in chimpanzees.

OBJECTIVE

Pentraxin 3 (PTX3) is an inflammatory mediator produced by neutrophils, macrophages, myeloid dendritic and endothelial cells. During sepsis a massive inflammatory activation and coagulation/fibrinolysis dysfunction occur. PTX3, as a mediator of inflammation, may represent an early marker of severity and outcome in sepsis.

METHODS

This study is based on a prospective trial regarding the impact of glycemic control on coagulation in sepsis. Ninety patients admitted to three general intensive care units were enrolled when severe sepsis or septic shock was diagnosed. At enrollment, we recorded sepsis signs, disease severity, coagulation activation [<em>prothrombin</em> <em>fragments</em> <em>1</em> + <em>2</em> (F(<em>1</em>+<em>2</em>))] and fibrinolysis inhibition [plasminogen activator inhibitor-<em>1</em> (PAI-<em>1</em>)]. We measured plasma PTX3 levels at enrollment, everyday until day 7, then at days 9, <em>1</em><em>1</em>, <em>1</em>3, <em>1</em>8, <em>2</em>3 and <em>2</em>8. Mortality was recorded at day 90.

RESULTS

Although not different on day <em>1</em>, PTX3 remained significantly higher in non-survivors than in survivors over the first 5 days (p = 0.00<em>2</em> by general linear model). On day <em>1</em>, PTX3 levels were higher in septic shock than in severely septic patients (p = 0.0<em>2</em>9). Day <em>1</em> PTX3 was significantly correlated with platelet count (p < 0.00<em>1</em>), SAPS II score (p = 0.006) and SOFA score (p < 0.00<em>1</em>). Day <em>1</em> PTX3 was correlated with F(<em>1</em>+<em>2</em>) concentration and with PAI-<em>1</em> activity and concentration (p < 0.05 for all).

CONCLUSIONS

Persisting high levels of circulating PTX3 over the first days from sepsis onset may be associated with mortality. PTX3 correlates with severity of sepsis and with sepsis-associated coagulation/fibrinolysis dysfunction.

BACKGROUND

There is emerging evidence that early trauma-induced coagulopathy (TIC) is mechanistically linked to disruption of the vascular endothelium and its glycocalyx, assessed by thrombomodulin and syndecan <em>1</em>, respectively. This study evaluated if degradation of the endothelial glycocalyx and ensuing release of its heparin-like substances induce autoheparinization and thereby contributes to TIC.

METHODS

Prospective observational study of 77 trauma patients admitted to a Level I trauma center having blood sampled at admission. Data on demography, hematology, Injury Severity Score, transfusion requirements, 30-day mortality, and thrombelastography (TEG, concurrent kaolin-activated/kaolin-heparinase-activated) were recorded. Retrospective analysis of plasma/serum for biomarkers reflecting endothelial glycocalyx and cell damage (syndecan <em>1</em>, thrombomodulin), tissue injury (histone-complexed DNA <em>fragment</em>s), sympathoadrenal activation (adrenaline, noradrenaline), coagulation activation/anticoagulation (<em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, fibrinogen, von Willebrand factor, factor XIII, antithrombin, protein C, activated protein C, tissue factor pathway inhibitor), fibrinolysis (tissue-type plasminogen activator, plasminogen activator inhibitor <em>1</em>) and inflammation (interleukin 6, terminal complement complex). Stratification of patients was according to the degree of TEG-measured heparinization.

RESULTS

Four patients (5.<em>2</em>%) displayed evidence of high-degree autoheparinization, and these patients had higher Injury Severity Score (median [interquartile range], 3<em>1</em> [<em>2</em>6-37] vs. <em>1</em>7 [<em>1</em>0-<em>2</em>6]), increased glucose (median, <em>1</em>3.6 vs. 8.0 mmol/L), and lower hemoglobin level (median, 5.8 vs. 8.4 mmol/L) and received more transfusions during the first <em>1</em> hour (median, 5 vs. 0) and <em>2</em>4 hours (median, <em>1</em>0 vs. 0) (all p < 0.05). Importantly, patients with autoheparinization had fourfold higher syndecan <em>1</em> levels (median [interquartile range], <em>1</em><em>1</em>6 ng/mL [78-<em>1</em>40 ng/mL] vs. 3<em>1</em> ng/mL [<em>1</em>8-49 ng/mL]), and they had higher international normalized ratio (median, <em>1</em>.4 vs. <em>1</em>.<em>1</em>), thrombomodulin (median, 4.<em>1</em> vs. <em>1</em>.7 ng/mL) and interleukin 6 (median, <em>1</em><em>2</em>9 vs. 7<em>1</em> pg/mL) but lower protein C (85% vs. <em>1</em>09%) (all p < 0.05), indicating profound endothelial damage, coagulopathy and inflammation.

CONCLUSIONS

Five percent of the patients with trauma in the present study had evidence of acute endogenous coagulopathy with autoheparinization by TEG, which appeared mechanistically linked to endothelial glycocalyx degradation. Acute endogenous autoheparinization may contribute to TIC.

METHODS

Prognostic study, level III.

OBJECTIVE

To test the hypothesis that the coagulation system and platelets are activated in sepsis, the uncomplicated and usually earliest stage of the septic process, and to compare the findings detected in sepsis with those found in severe sepsis and septic shock.

METHODS

Prospective study comparing patients with sepsis, severe sepsis, and septic shock, and healthy volunteers.

METHODS

General intensive care unit in a tertiary university hospital.

METHODS

Seventy-four consecutive septic patients (45 with sepsis, <em>1</em>5 with severe sepsis, and <em>1</em>4 with septic shock). Fourteen healthy volunteers served as control subjects.

METHODS

None.

RESULTS

After blood sampling, molecular activation markers of coagulation (<em>prothrombin</em> <em>fragments</em> <em>1</em> and <em>2</em>, fibrinopeptide A, thrombin-antithrombin complexes, and monomers of fibrin) and of platelets (beta-thromboglobulin and platelet factor 4), several coagulation factors, global tests of coagulation (<em>prothrombin</em> time and activated partial thromboplastin time), and platelet count (PTL) were measured. In sepsis, <em>prothrombin</em> <em>fragments</em> <em>1</em> and <em>2</em>, fibrinopeptide A, thrombin-antithrombin complexes, and monomers of fibrin were increased to <em>2</em>.5<em>2</em>+/-0.<em>2</em><em>1</em> nmol/L, <em>2</em>0.88+/-<em>2</em>.5<em>2</em> ng/mL, 33.8+/-<em>2</em>.9 microg/L, and 69% positive, respectively, compared with control subjects (0.86+/-063 nmol/L, <em>1</em>.<em>1</em>4+/-0.<em>1</em>5 ng/mL, <em>1</em>6.07+/-<em>1</em>.0<em>1</em> microg/L, and 0%, respectively). Beta-Thromboglobulin and the beta-thromboglobulin-to-platelet factor 4 ratio were also increased to <em>1</em>07.87+/-<em>1</em><em>1</em>.87 IU/mL and 8.86+/-<em>1</em>.06, compared with controls (<em>1</em>8.36 +/-<em>2</em>.99 IU/mL and <em>2</em>.67+/-0.5<em>2</em>, respectively). With the exception of a decrease in factor XII and an increase in fibrinogen, coagulation factors, global coagulation tests, and PTL were not changed in sepsis. In severe sepsis and mainly in septic shock, coagulation factors were markedly decreased, global coagulation tests were prolonged, and PTL was reduced. All changes were independent of the causative infectious pathogen.

CONCLUSIONS

Coagulation system and platelets are strongly activated in sepsis. In this stage, only factor XII is decreased. In contrast, in severe sepsis and mainly in septic shock, most of the coagulation factors are depleted, PTL is decreased, and global coagulation tests are prolonged, indicating exhaustion of hemostasis. Finally, Gram-positive, Gram-negative, and other microorganisms produce identical impairment of coagulation.

Thirty-three subjects with sickle cell disease (SCD), <em>1</em><em>1</em> during episodes of pain and <em>2</em><em>2</em> during periods without pain, were evaluated for in vivo thrombogenic activities as compared with <em>1</em>0 normal black control subjects. Measurements were performed for (<em>1</em>) platelet surface activation, assessing flow cytometric expression of activated integrin alpha(IIb)beta(3) receptor (GPIIb/IIIa, CD4<em>1</em>a) and P-selectin (CD6<em>2</em>p); (<em>2</em>) platelet and erythrocyte surface procoagulant activities, measuring flow cytometric binding of activated factor (FVa) and annexin V; (3) plasma levels of platelet-specific secreted proteins platelet factor 4 (PF4) and beta-thromboglobulin (betaTG); (4) plasma markers of thrombin generation, <em>prothrombin</em> activation <em>fragment</em> (F(<em>1</em>.<em>2</em>)), and thrombin: antithrombin complex (TAT); and (5) plasma markers of fibrinolysis, D -dimer, and plasmin:antiplasmin complex (PAP). As compared with control subjects, asymptomatic subjects with SCD demonstrated significantly increased platelet activation (P <.0<em>1</em> for P-selectin and annexin V binding), elevated plasma levels of PF4 and betaTG (P <.0<em>1</em> and P <.03, respectively), and increased plasma concentrations of F(<em>1</em>.<em>2</em>), TAT, PAP, and D -dimer (P <.05 in all cases). During episodes of SCD pain, platelet activation was increased as compared with periods without pain (P <.0<em>1</em> for expression of activated integrin alpha(IIb)beta(3) receptor and P-selectin and binding of FVa and annexin V), erythrocytes expressed procoagulant activities (P <.0<em>1</em> for FVa and annexin V binding), and platelet microparticles appeared in the circulation (3% to 30%; P <.00<em>1</em>). SCD pain episodes were associated with elevated plasma levels of F(<em>1</em>.<em>2</em>), TAT, PAP, and D -dimer (P <.05 as compared with asymptomatic intervals). The frequency of pain episodes correlated with enhanced platelet procoagulant activity (r = 0.6<em>1</em>, P <.05) and elevated plasma fibrinolytic activity (r = 0.74, P <.0<em>1</em>) measured during periods without pain. Plasma fibrinolytic activity was inversely correlated with time to the next pain episode (r = -0.50, P <.05). Thus, asymptomatic subjects with SCD exhibit ongoing platelet activation, thrombin generation, and fibrinolysis that increases during episodes of pain. These changes are predictive of frequency of pain and interval to next pain episode, thereby implicating thrombogenic activity in the development of SCD pain episodes.

During normal pregnancy the hemostatic balance changes in the direction of hypercoagulability, thus decreasing bleeding complications in connection with delivery. The most important initial factor for acute hemostasis at delivery is, however, uterine muscle contractions, which interrupt blood flow. Global tests such as Sonoclot signature, the Thromboelastogram, and a new method analyzing overall plasma hemostasis, all show changes representative of hypercoagulability during pregnancy. Increased endogenous thrombin generation, acquired activated protein C resistance, slightly decreased activated partial thromboplastin time (aPTT) and increased <em>prothrombin</em> complex level (PT) measured as international normalized ratio (INR) of less than 0.9 have been reported as well. In normal pregnancy, the platelet count is within normal range except during the third trimester when benign gestational thrombocytopenia, 80 to <em>1</em>50 x <em>1</em>0 9/L, can be observed. Platelet turnover is usually normal. Activation of platelets and release of beta-thromboglobulin and platelet factor 4 are reported. The bleeding time is unchanged during normal pregnancy. Most blood coagulation factors and fibrinogen increase during pregnancy. Factor (F) XI is the only blood coagulation factor that decreases. Blood coagulation inhibitors are mainly unchanged but the level of free protein S decreases markedly and the level of tissue factor pathway inhibitor increases. Thrombomodulin levels increase during pregnancy. Fibrinolytic capacity is diminished during pregnancy, mainly because of markedly increased levels of plasminogen activator inhibitor-<em>1</em> (PAI-<em>1</em>) from endothelial cells and plasminogen activator inhibitor-<em>2</em> (PAI-<em>2</em>) from the placenta. Thrombin-activated fibrinolysis inhibitor is reported to be unaffected. The total hemostatic balance has been studied by analyses of <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, thrombin-antithrombin complex, fibrinopeptide A, soluble fibrin, D-dimer, and plasmin-antiplasmin complex. There is activation of blood coagulation and a simultaneous increase in fibrinolysis without signs of organ dysfunction during normal pregnancy. These changes increase as pregnancy progresses. During delivery, there is consumption of platelets and blood coagulation factors, including fibrinogen. Fibrinolysis improves and increases fast following childbirth and expulsion of the placenta, resulting in increased D-dimer levels. These changes are self-limiting at normal delivery. The hemostatic changes, noted during pregnancy, normalize after delivery within 4 to 6 weeks. Platelet count and free protein S, however, can be abnormal longer. Hemostasis should not be tested earlier than 3 months following delivery and after terminating lactation to rule out influences of pregnancy. PAI-<em>1</em> and PAI-<em>2</em> levels decrease fast postpartum, but PAI <em>2</em> has been detected up to 8 weeks postpartum. alpha <em>2</em> -antiplasmin, urokinase, and kallikrein inhibitor levels have been reported to be increased 6 weeks postpartum.