In a prospective study including <em>1</em>6 patients with multiple trauma and head injury and <em>1</em>4 patients with isolated head injury we measured plasma levels of <em>prothrombin</em> <em>fragment</em> <em>1</em> and <em>2</em> (F<em>1</em> + <em>2</em>) and thrombin/antithrombin III complex (TAT) on admission and on days <em>1</em>, <em>2</em>, 3, and 7 after the incident. On admission, all patients had values of F<em>1</em> + <em>2</em> and TAT above the reference range. Admission levels of both F<em>1</em> + <em>2</em> and TAT were significantly higher compared with levels on the following days. Admission levels of F<em>1</em> + <em>2</em> was significantly correlated to the Injury Severity Score. TAT was higher in patients with multiple trauma than in patients with isolated head injury and were significantly correlated to the Injury Severity Score on admission and on day 3. Levels of F<em>1</em> + <em>2</em> were significantly lower on day <em>1</em> in four patients with post-traumatic pulmonary dysfunction compared with patients without pulmonary dysfunction. With respect to levels of TAT, no differences were detected between patients with and without pulmonary dysfunction.

OBJECTIVE

In vitro studies suggest an influence of hyperhomocysteinemia on the coagulation system, but the influence of mild hyperhomocysteinemia in vivo is unclear.

RESULTS

We studied the relation between homocysteine and markers of coagulation activation and endothelial cell activation in <em>2</em>79 patients with established atherosclerotic disease. In addition, we performed an investigator-blinded placebo-controlled cross-over study to investigate the influence of acute hyperhomocysteinemia by oral methionine load on these markers in <em>2</em>0 healthy volunteers. In the atherosclerotic patients <em>prothrombin</em> <em>fragment</em> F<em>1</em>+<em>2</em> and soluble thrombomodulin (sTM) were associated with homocysteine in univariate analyses (P = 0.003 and P = 0.00<em>1</em>, respectively), but not in multivariate analyses. Age, creatinine and MTHFR C677T polymorphism were major determinants of homocysteine concentration. MTHFR C677T polymorphism status was not associated with F<em>1</em>+<em>2</em> and sTM. Median homocysteine concentrations increased in the healthy volunteers after methione load. However, after methionine load or after placebo, we did not observe different plasma concentrations of F<em>1</em>+<em>2</em> (0.9 nmol L-<em>1</em> vs. 0.9 nmol L-<em>1</em>, P = 0.39), d-dimer (<em>1</em>53 micro g L-<em>1</em> vs. <em>1</em>5<em>1</em> micro g L-<em>1</em>, P = 0.63) and von Willebrand factor (<em>1</em>03% vs. <em>1</em>07%, P = <em>1</em>.00).

CONCLUSIONS

These results provide evidence against a major effect of mild hyperhomocysteinemia on activation of the coagulation system and endothelial cell activation in vivo.

BACKGROUND

Although the general improvement caused by recombinant human erythropoietin (rHuEPO) in the correction of uraemic anaemia cannot be questioned, some data suggest that the changes in the haemostasis, endothelial function and oxidative stress (SOX) are induced. The aim of the present study was to investigate the effect of one-year rHuEPO therapy on the coagulation activation, endothelial injury markers and SOX in haemodialysis (HD) patients.

METHODS

Assessment of coagulation activation pathway: tissue factor (TF), its inhibitor (TFPI) and <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>); endothelial injury markers: von Willebrand factor antigen (vWF:Ag) and thrombomodulin (TM); and several parameters related to SOX: total peroxide, Cu/Zn superoxide dismutase (Cu/Zn SOD) and autoantibodies to oxidized LDL (OxLDL-Ab) levels were performed in stable HD patients, treated for <em>1</em><em>2</em> months with rHuEPO (n=<em>1</em>8; mean dose <em>1</em><em>1</em>3.5+/-4<em>1</em> U/kg/week) or not (with Hg(<em>1</em>0 g/dl, n=8 and with Hg><em>1</em>0 g/dl, n=<em>1</em><em>2</em>), none of them on iron therapy.

RESULTS

Patients with Hg(<em>1</em>0 g/dl had a significantly lower erythrocytes count, Ht and Hg levels than those with Hg><em>1</em>0 g/dl and those on rHuEPO therapy. Long-term rHuEPO therapy does not affect coagulation pathway and SOX markers. Treatment with this hormone resulted in a tendency to decrease TM and vWF:Ag concentrations, however these changes did not reach a statistical significance.

CONCLUSIONS

These results suggest that one-year rHuEPO therapy seems to exert no additional influence on coagulation activation, endothelial cell damage/activation markers and oxidative stress in patients undergoing regular HD in the absence of concomitant iron supplementation and irrespective from haemoglobin levels.

Background Although cholesterol levels are known to be decreased in sickle cell disease (SCD), the level of pro-inflammatory high-density lipoprotein cholesterol (proHDL) and its association with clinical complications and laboratory variables has not been evaluated. Design and methods Plasma levels of total cholesterol, high-density lipoprotein cholesterol (HDL), proHDL, and selected clinical and laboratory variables were ascertained in a cohort of SCD patients and healthy African American control subjects in this single-center, cross-sectional study. Results Although total cholesterol was significantly lower in SCD patients compared with control subjects, HDL and proHDL levels were similar in both the SCD and control groups. In univariate analyses, proHDL was correlated with echocardiography-derived tricuspid regurgitant jet velocity. ProHDL was higher in SCD patients with suspected pulmonary hypertension (PHT) compared to patients without suspected PHT. ProHDL was positively correlated with lactate dehydrogenase, total bilirubin, direct bilirubin, indirect bilirubin, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, D-dimer, and thrombin-antithrombin complexes. In multivariable analyses, only higher lactate dehydrogenase and direct bilirubin levels were associated with higher levels of proHDL. Conclusions SCD is characterized by hypocholesterolemia. Although proHDL is not increased in SCD patients compared with healthy controls, it is significantly associated with markers of liver disease. In addition, proHDL is associated with tricuspid regurgitant jet velocity and markers of coagulation, although these associations are not significant in multivariable analyses.

Recombinant activated factor VIIa (FVIIa) is a bypassing agent used to treat bleeding episodes in haemophilia patients with inhibitors to factor VIII (FVIII) and factor IX. The pharmacological effect of FVIIa is short-lived and therefore with the recommended dose of 90 μg kg(-<em>1</em>), a bleeding episode is treated with multiple injections. A long-acting form of FVIIa that can ensure adequate haemostasis with a single infusion, without increasing the thrombotic risk, would therefore be beneficial. PEGylated liposomes (PEGLip) have been shown to bind FVIIa and to improve haemostatic efficacy in preclinical experiments. In the present phase I/II clinical trial, we assessed the safety and efficacy of PEGLip-formulated FVIIa in severe haemophilia A patients (FVIII≤<em>1</em>%) with inhibitors to FVIII. Each patient received one prophylactic infusion of standard FVIIa and one prophylactic infusion of PEGLip-formulated FVIIa. The order of the infusions was randomized and the two infusions were separated by a ten-day washout period. Efficacy assessed by thromboelastography revealed that PEGLip-FVIIa induced significantly shorter clotting times and produced higher clot firmnesses than standard FVIIa. Thrombin generation assays showed that PEGLip-FVIIa induced faster thrombin generation and higher peak levels of thrombin than standard FVIIa. These effects lasted up to 5 h postinfusion. Measurements of D-dimer, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> and fibrinogen showed no significant differences between the PEGLip-FVIIa and standard FVIIa treatments. PEGLip-FVIIa therefore showed improved haemostatic efficacy without increased risk of thrombosis and may be further developed for the treatment for bleeding episodes in haemophilia patients with inhibitors.

BACKGROUND

The purpose of this study was to evaluate the long-term coagulation status of patients undergoing malignancy resection.

METHODS

A prospective observational trial was conducted with informed consent in 5<em>2</em> patients (age 66 ± <em>1</em>0 years and 60% male) with thoracoabdominal tumors (pancreas [n = <em>1</em>8, 35%], esophagus [n = <em>1</em>3, <em>2</em>5%], liver [n = 7, <em>1</em>4%], stomach [n = 6, <em>1</em><em>2</em>%], bile duct [n = 3, 6%], retroperitoneal [n = 3, 6%], and duodenum [n = <em>2</em>, 4%]) with 6- to <em>1</em><em>2</em>-month follow-up. Coagulation was evaluated with rotational thromboelastography (ROTEM) on whole blood and with a panel of hemostatic markers on stored plasma.

RESULTS

Maximum clot firmness (MCF) in the intrinsic, extrinsic, and fibrinogen pathways increased immediately postoperatively and then decreased by 9.<em>2</em> ± 4.<em>1</em> months (p < 0.05). Markers of thrombin generation (<em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>, fibrinolysis [D-dimer], and endothelial activation [coagulation factor VIII]) were elevated at all time points. The ROTEM pattern depended on histologic type and cancer location. All esophageal tumors were adenocarcinoma and demonstrated similar patterns to the overall population, with MCF differences over time in all 3 pathways (all p < 0.05). Regarding tumors of the pancreas or liver, there were no statistically significant differences when comparing all 3 time periods, but there were time-related differences when evaluating only primary adenocarcinomas of the liver (all p < 0.05). Three patients (6%) developed venous thromboembolism (VTE) and had decreased clot formation time, increased angle, and increased MCF (all p < 0.05).

CONCLUSIONS

Cancer patients at risk for VTE can be identified with a point-of-care ROTEM test and may benefit from additional anticoagulation. Biomarkers reflecting different functional hemostasis activity groups (fibrinolysis, thrombin generation, and endothelial activation) confirm the ongoing prothrombotic state. The ROTEM demonstrated increased hypercoagulability postoperatively, which returned to baseline in long-term follow-up. Reversal of cancer-induced hypercoagulability occurred in some patients and varied with tumor histology and location.

Intracranial surgery is often complicated by thromboembolic events including the life-threatening pulmonary embolism. After head trauma and in patients with brain tumors disseminated intravascular coagulation (DIC) can occur, characterized by the triggering of the coagulation cascade and the depletion of coagulation factors which ultimately leads to bleeding. The identification of patients at high risk as well as the early diagnosis of hemostatic problems uses routine laboratory parameters such as partial thromboplastin time and <em>prothrombin</em> time reflecting the intrinsic and the extrinsic pathway of the coagulation respectively. Thrombin antithrombin III complexes (TAT) and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>) are further indicators of an activation of the coagulation whereas fibrinogen degradation products (FDP) refer to the fibrinolytic system. The basic principles of coagulation and fibrinolysis are summarized as well as the changes of laboratory parameters accompanying DIC, hypercoagulability and hyperfibrinolysis.

Bioincompatibility is the total of side effects during hemodialysis (HD) including, amongst others, changes in platelet (PLT) level. Deviations in PLT count, immature PLT count, PLT morphology, CD6<em>2</em>p expression, Platelet Factor 4 (PF4), β-Thromboglobulin (β-TG), serotonin, Thrombin-Antithrombin III (TAT) and <em>Prothrombin</em> <em>Fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>) are monitored before and during treatment with HD in order to elucidate the interaction between modifications in PLT morphology, PLT activation and markers concerning activation of coagulation. Different patterns with time indicate that there is no correlation between an increased amount of depleted PLTs and increased amounts of PLT activation markers such as CD6<em>2</em>p, PF4, β-TG and serotonin. A statistically significant correlation between increased PLT activation markers and markers for increased activation of coagulation such as TAT and F<em>1</em>+<em>2</em> has not been established. Only a weak correlation is demonstrated between the increase of markers for activation of coagulation and the decrease in PLT counts, immature PLT counts and depleted PLTs during HD treatment. The change in the extracorporeal circuit during HD is probably a more critical factor in the mechanism leading to activation of the coagulation pathway than the modifications in PLT morphology.

The pretreatment plasma levels of <em>prothrombin</em> <em>fragment</em> F<em>1</em>+<em>2</em> and thrombin-antithrombin III complex (TAT) were measured in 56 consecutive patients with gynecological cancer and in 33 apparently healthy volunteer nonpregnant women as control. <em>Prothrombin</em> <em>fragment</em> F<em>1</em>+<em>2</em> concentrations were significantly elevated in the <em>1</em>8 patients with ovarian cancer (median, 3.<em>2</em> nmol/ liter; range, 0.9-<em>1</em>7.0 nmol/liter, P < 0.000<em>1</em>), in the <em>2</em>4 patients with cervical cancer (median, <em>1</em>.7 nmol/liter; range, 0.6-<em>1</em>5.0 nmol/ liters, P < 0.000<em>1</em>), and in the <em>1</em>4 patients with endometrial cancer (median, <em>1</em>.5 nmol/liter; range, 0.6-3.0 nmol/liter, P = 0.036) when compared to controls (median, <em>1</em>.0 nmol/liter; range, 0. <em>1</em> -<em>2</em>.<em>1</em> nmol/ liter). Similarly, TAT levels were significantly higher in patients with ovarian cancer (median, 5.3 microgram /ml; range, <em>1</em>.3-65.0 microgram/ml , P < 0.000<em>1</em>), cervical cancer (median, 3.8 microgram/ml; range, <em>2</em>.<em>1</em> - <em>1</em><em>1</em>.0 microgram / ml, P < 0.000<em>1</em>), and endometrial cancer (median, <em>2</em>.7 microgram/ml; range, <em>1</em>.9-<em>1</em>9.0 microgram /ml, P = 0.008) when compared to controls (median, <em>2</em>.<em>2</em> microgram/ml; range, <em>1</em>.0-5.0 microgram/ml). <em>Prothrombin</em> <em>fragment</em> F<em>1</em>+<em>2</em> levels correlated with TAT levels (r = 0.659, P < 0.000<em>1</em>). Among ovarian cancer patients, <em>prothrombin</em> <em>fragment</em> F<em>1</em>+<em>2</em> and TAT concentrations correlated with FIGO stage (III-IV versus <em>1</em>, P = 0.0<em>1</em> and P = 0.003, respectively) and CA <em>1</em><em>2</em>5 levels (P 0.0<em>2</em> and P < 0.000<em>1</em>, respectively). The present data confirmed the occurrence of hemostasis activation in patients with gynecological cancer, and in particular in those with ovarian cancer.

At time of diagnosis, most cancer patients present with laboratory evidence of systemic coagulation activation. After treatment with curative intent, these hemostatic alterations seemingly disappear as seen in colorectal cancer with regard to <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>), thrombin-antithrombin complex (TAT), and soluble fibrin (SF). The aim of this study was to investigate whether coagulation activation recurs with cancer recurrence and to study whether preoperative coagulation tests have any prognostic value in colorectal cancer. Plasma F<em>1</em>+<em>2</em>, TAT, and SF levels were prospectively recorded from <em>1</em><em>1</em>3 patients followed after curative resection of colorectal cancer. The patients were seen in clinic after 3, 6, <em>1</em><em>2</em>, and <em>1</em>8 months, and after <em>2</em>, 3, 4, and 5 years. Coagulation reactivation was observed at the time of recurrence, as demonstrated by significantly increased plasma TAT and SF, along with a non-significant increase (P = 0.09) in F<em>1</em>+<em>2</em>. Preoperative values of F<em>1</em>+<em>2</em>, TAT, and SF did not show association with prognosis.

Previous work has shown that bovine <em>prothrombin</em> <em>fragment</em> <em>1</em> binds to supported planar membranes composed of phosphatidylcholine and phosphatidylserine in a Ca(<em>2</em>+)-specific manner (Tendian et al. (<em>1</em>99<em>1</em>) Biochemistry 30, <em>1</em>099<em>1</em>; Pearce et al. (<em>1</em>99<em>2</em>) Biochemistry 3<em>1</em>, 5983-5995). In the present work, fluorescence pattern photobleaching recovery has been used to examine the effect of membrane-bound <em>fragment</em> <em>1</em> on the translational diffusion coefficients of two fluorescent phospholipids in fluid-like phosphatidylserine/phosphatidylcholine Langmuir-Blodgett monolayers. The results show that saturating concentrations of <em>fragment</em> <em>1</em>, in the presence of Ca<em>2</em>+, reduce the diffusion coefficient of nitrobenzoxadiazolyl-conjugated phosphatidylserine (NBD-PS) and nitrobenzoxadiazolyl-conjugated phosphatidylcholine (NBD-PC) by factors of approximately four and two, respectively. Ca<em>2</em>+ or <em>fragment</em> <em>1</em> alone do not have a statistically significant effect on NBD-PS or NBD-PC diffusion. In addition, a nonspecific protein (ovalbumin) does not change the diffusion coefficients of the fluorescent phospholipids either in the absence or presence of Ca<em>2</em>+. The fractions of the fluorescent phospholipids that are laterally mobile are approximately 0.9 for all samples. These results are interpreted with several models for possible mechanisms by which extrinsically bound proteins might retard phospholipid diffusion in membranes.

Heparin infusion may cause heparin resistance and may affect monitoring by measurement of the activated coagulation time (ACT), making the assessment of anticoagulation difficult, with the risk of over- or undertreatment, especially during cardiac surgery. We studied two groups of patients undergoing cardiopulmonary bypass (CPB): patients on heparin infusions (group H) and heparin-naive controls (group C). All patients received heparin 300 IU kg(-<em>1</em>) before CPB and a further dose of 5000 IU if the ACT 5 min after commencing bypass was less than 400 s. Measurements of ACT, heparin concentration, antithrombin-3, thrombin-antithrombin complex, <em>prothrombin</em> <em>fragment</em> F(<em>1</em>+<em>2</em>) and D-dimers were made before and 5 and <em>2</em>0 min after start of CPB. A second dose of heparin was given to eight out of <em>1</em>8 patients in group C and <em>1</em>0 out of <em>2</em>4 in group H. Antithrombin-3 in group H was significantly less than in group C at 5 min [59 (<em>1</em>4) vs 5<em>2</em> (9)%, P<0.05]. ACT was significantly lower in group H than group C at <em>2</em>0 min [387 (64) vs 43<em>1</em> (67) s, P<0.05]. Despite ACTs of less than 400 s in both groups, no coagulation was seen, suggesting that 300 IU kg(-<em>1</em>) heparin is a safe dose for anticoagulation in CPB even after heparin therapy.

OBJECTIVE

Aprotinin is frequently used to reduce blood loss during cardiac surgery; however, it also causes renal injury. Since aprotinin reduces nitric oxide (NO) and prostaglandin I(<em>2</em>) (PGI(<em>2</em>)), and both cause vasodilation and inhibit activation of neutrophils and platelets, their reduction may be responsible for the injury. This study was to determine whether the combination of aprotinin with NO and prostaglandin E(<em>1</em>) (PGE(<em>1</em>), an analogue of PGI(<em>2</em>)) can attenuate renal injury associated with aprotinin during cardiopulmonary bypass (CPB).

METHODS

Thirty mongrel dogs were equally divided into five groups, with each group receiving CPB and aprotinin, NO, PGE(<em>1</em>), a combination of the three or no treatment (control). Serum creatinine and creatinine clearance were determined. To elucidate the mechanism, neutrophil, platelet and thrombin activations were also assessed.

RESULTS

After CPB, serum creatinine increased and creatinine clearance decreased in all dogs. These changes were similar among the NO, PGE(<em>1</em>), aprotinin and control groups, but were significantly smaller in the combination group. Similarly, myeloperoxidase activities in tissues, CD<em>1</em><em>1</em>b expression, plasma elastase, prothrombin fragment (PTF) <em>1</em>+<em>2</em> and platelet activation factor were lower, whereas neutrophil and platelet counts were higher in the combination group than in the other groups (P<0.05).

CONCLUSIONS

Aprotinin combined with NO and PGE(<em>1</em>) produced synergistic protective effects and improved renal function, due partly to inhibition of platelet and neutrophil activation and suppression of thrombin formation.

Thromboxane (Tx) A<em>2</em> biosynthesis is enhanced in the majority of patients with type IIa hypercholesterolemia. Because blood clotting activation is an important component of the inflammatory response, involved in the initiation and progression of atherosclerotic plaques, we have investigated TxA<em>2</em> biosynthesis, neutrophil activation and thrombin generation in <em>2</em>4 patients with type IIa hypercholesterolemia. Urinary <em>1</em><em>1</em>-dehydro-TxB<em>2</em>, was significantly higher (p = 0.000<em>1</em>) in patients than in <em>2</em>4 sex- and age matched healthy subjects. Similarly, <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>), thrombin-antithrombin III complexes and plasma elastase were significantly higher in patients than in controls. Urinary <em>1</em><em>1</em>-dehydro-TxB<em>2</em> excretion was correlated with plasma elastase (r = 0.758; p = 0.000<em>1</em>), and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (r = 0.804; p = 0.00<em>1</em>). The enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor simvastatin (<em>2</em>0 mg/day for <em>2</em> months) significantly reduced cholesterol levels, urinary <em>1</em><em>1</em>-dehydro-TxB<em>2</em> excretion, plasma elastase and plasma F<em>1</em> + <em>2</em> in 8 patients. We conclude that type IIa hypercholesterolemia is associated with biochemical evidence of platelet, neutrophil and blood clotting activation. The relationship between these events remains to be investigated.

Platelets play an important role in the activation of coagulation. P<em>2</em>Y<em>1</em><em>2</em> receptor inhibition may be beneficial in inflammatory states. Prasugrel, a potent irreversible inhibitor of P<em>2</em>Y<em>1</em><em>2</em> receptor-induced platelet activation may reduce activation of coagulation in a human LPS (lipopolysaccharide) model. A double-blind, randomized, crossover trial with a minimum washout period of 6 weeks was performed. Sixteen subjects were randomly assigned to a treatment group that received prasugrel or placebo <em>2</em> h before infusion of a bolus of LPS (<em>2</em> ng/kg of body weight), whereas four subjects were assigned to a control group receiving prasugrel or placebo without LPS. hcDNA (histone-complexed DNA), coagulation and platelet-specific parameters were measured by enzyme immunoassay. Leucocyte aggregate formation was analysed by flow cytometry, and thromboelastometry was performed. LPS infusion markedly activated coagulation. However, prasugrel did not reduce changes in <em>prothrombin</em> <em>fragments</em> <em>1</em> and <em>2</em> (F<em>1</em>+<em>2</em>), thrombin-antithrombin complexes, microparticle-associated tissue factor, CD40 ligand, P-selectin, platelet-leucocyte aggregation, hcDNA levels or the coagulation profile measured by thromboelastometry. hcDNA plasma levels increased approximately 6-fold after LPS infusion in both treatment groups, but not in the control groups. Potent irreversible P<em>2</em>Y<em>1</em><em>2</em> inhibition by prasugrel does not affect LPS-induced coagulation activation. The 6-fold increased hcDNA plasma levels after infusion of LPS indicates the formation of neutrophil extracellular traps during sterile inflammation.

OBJECTIVE

Coagulation system activation in extracorporeal membrane oxygenation results in hemostatic derangements. Thrombin generation markers like <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> and thrombin-antithrombin complex are sensitive markers of hypercoagulability. Plasmin-antiplasmin complex is a sensitive marker for fibrinolysis. D-dimers reflect thrombin generation and fibrinolysis. The aim was to identify the extent of hemostasis activation during extracorporeal membrane oxygenation by measuring thrombin-antithrombin complex, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, plasmin-antiplasmin complex, and D-dimer.

METHODS

Prospective cohort study.

METHODS

Tertiary care academic center.

METHODS

Children placed on extracorporeal membrane oxygenation from April <em>2</em>0<em>1</em><em>1</em> to January <em>2</em>0<em>1</em>3.

METHODS

Prothrombin <em>fragment</em> <em>1</em>+<em>2</em>, thrombin-antithrombin complex, plasmin-antiplasmin complex, and D-dimer were measured on days <em>1</em> and 5 of extracorporeal membrane oxygenation.

RESULTS

Data presented as median (interquartile range); nonparametric tests were done using SPSS. Twenty-nine children (5<em>2</em>% < 30 d old [neonates], median extracorporeal membrane oxygenation length <em>1</em>5<em>1</em> hr) were studied. Complications included thrombosis in <em>1</em>4%, bleeding in 45%, and thrombosis and bleeding together in <em>1</em>0%. Thrombin-antithrombin complex, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, plasmin-antiplasmin complex, and D-dimer levels were high on day <em>1</em> and remained increased on extracorporeal membrane oxygenation. In neonates, all levels were higher on day 5 compared with day <em>1</em>: thrombin-antithrombin complex (55.6 μg/L [30.7-76.0] vs <em>1</em>8.7 μg/L [<em>1</em>0.9-34.6]; p = 0.03), <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (<em>2</em>,038 pmol/L [<em>1</em>,093-4,0<em>1</em>8.5] vs 377.5 pmol/L [334.3-<em>1</em>,<em>1</em>03.0]; p = 0.00), plasmin-antiplasmin complex (<em>2</em>,<em>1</em>60 μg/L [786-3,090] vs 398 μg/L [<em>2</em>96.8-990.8]; p = 0.00), and D-dimer (3.0 μg/mL [<em>1</em>.9-<em>1</em><em>1</em>.5] vs <em>1</em>.5 μg/mL [0.6-<em>2</em>.9]; p = 0.0<em>1</em>). Thrombin-antithrombin complex, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, plasmin-antiplasmin complex, and D-dimer levels did not correlate with anti-Xa activity or heparin dose. In bleeders older than 30 days, plasmin-antiplasmin complex stayed elevated on day 5, but in patients with no bleeding complications, plasmin-antiplasmin level showed a declining trend. In neonates, plasmin-antiplasmin levels increased over the course of extracorporeal membrane oxygenation irrespective of bleeding.

CONCLUSIONS

Despite our best efforts at adequate anticoagulation with unfractionated heparin, neonates showed persistent increase in coagulation activation on extracorporeal membrane oxygenation. Fibrinolysis activation may contribute to bleeding in patients older than 30 days. Different anticoagulation protocols should be individualized based on age.

BACKGROUND

We and others have demonstrated that administration of thrombolytic agents causes the generation of thrombosis-promoting agents. At present, we have studied whether formation in vivo of excessive amounts of plasmin is responsible for the activation of coagulation in patients treated with recombinant tissue-type plasminogen activator.

METHODS

Modified crossed immunoelectrophoresis was used for determination of the plasminogen-binding form of alpha <em>2</em>-antiplasmin. Enzyme-linked immunosorbent assay methods were used for determination of hemostatic reaction products.

RESULTS

The association between the generation of hemostatic reaction products and the exhaustion of the plasminogen-binding form of alpha <em>2</em>-antiplasmin (PB alpha <em>2</em>AP) was studied in <em>2</em><em>1</em> patients with acute myocardial infarction and <em>1</em><em>1</em> patients with unstable angina pectoris who were given a 3-hour, <em>1</em>00-mg intravenous infusion of recombinant tissue-type plasminogen activator (rt-PA). We observed in all patients a fall in blood concentrations of PB alpha <em>2</em>AP (P < 0.0<em>1</em>) after <em>2</em>.<em>2</em>5 hours of treatment and, simultaneously, a significant increase in fibrin degradation products (P < 0.0<em>1</em>), D-dimer (P < 0.0<em>1</em>), fibrinogen degradation products (P < 0.0<em>1</em>), <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (P < 0.0<em>1</em>), and thrombin-antithrombin III complexes (P < 0.0<em>1</em>). When we evaluated individual data, we observed high concentrations of the reaction products when the PB alpha <em>2</em>AP concentration after <em>2</em>.<em>2</em>5 hours of treatment was lower than <em>2</em>5% of the pretreatment values. Also, we observed highly significant associations between the increase in the plasma concentrations of fibrin degradation products and thrombin-antithrombin III complexes (rs = 0.7<em>2</em>; P < 0.0<em>1</em>), the increase in plasma concentrations of fibrin degradation products and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (rs = 0.63; P < 0.0<em>1</em>), the increase in plasma concentrations of D-dimer and thrombin-antithrombin III complexes (rs = 0.78; P < 0.0<em>1</em>), and the increase in plasma concentrations of D-dimer and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (rs = 0.79; P < 0.0<em>1</em>).

CONCLUSIONS

Generation of excessive amounts of plasmin is the main factor in producing the procoagulant response in patients who receive thrombolytic therapy with rt-PA, and intravenous heparin does not abolish this response. Plasmin inhibitors might be used in relation to thrombolytic therapy as indirect "antithrombotics."

OBJECTIVE

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with major inflammatory triggers that cause marked activation of the microcirculation. This inflammatory response is associated with significant organ dysfunction. How this response causes organ dysfunction is not well understood; consequently, few interventions exist to prevent or treat it. In other acute inflammatory conditions, such as sepsis, increased coagulation activation in the microcirculation may be a cause of organ injury. We documented the association between coagulation activation and organ dysfunction to investigate whether coagulation activation also plays a role in organ injury following cardiac surgery with CPB.

METHODS

Prospective study of 30 patients undergoing cardiac surgery with CPB. <em>Prothrombin</em> <em>fragment</em> (PTF) <em>1</em> + <em>2</em> and plasminogen activator inhibitor (PAI) activity were measured, and levels correlated with postoperative measures of organ function including the left-ventricular stroke work index, the Pao(<em>2</em>)/fraction of inspired oxygen (Fio(<em>2</em>)) ratio, and creatinine levels.

RESULTS

PTF levels increased eightfold (p < 0.05), and PAI activity increased threefold (p < 0.05) over the first 4 h after CPB. PTF levels were correlated with deteriorations in the left-ventricular stroke work index (p = 0.04), the Pao(<em>2</em>)/Fio(<em>2</em>) ratio (p = 0.0<em>2</em>), and creatinine levels (p = 0.0<em>2</em>).

CONCLUSIONS

Levels of coagulation activation are associated with markers of postoperative organ dysfunction. Additional studies are warranted to investigate whether strategies that limit coagulation activation are associated with reductions in postoperative organ dysfunction.

Increased plasma fibrinogen levels and hemostatic abnormalities suggestive of a prothrombotic state are present in patients with end-stage renal failure and could contribute to increased cardiovascular morbidity in these patients. We investigated the relationship between abnormalities of the hemostatic system and the degree of renal failure and whether these abnormalities are associated with increased prevalence of cardiovascular events in patients with arteriolar nephrosclerosis. In 4<em>2</em>5 patients recruited at a hypertension clinic we assessed the renal function by creatinine clearance, urinary protein excretion, and microalbuminuria, the prevalence of atherosclerotic disease, and measured <em>prothrombin</em> time, activated partial thromboplastin time. fibrinogen, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>), D-dimer, and antithrombin. Early impairment of renal function (creatinine clearance, 30 to 89 ml/min per <em>1</em>.73 m<em>2</em> of body surface area) caused by arteriolar nephrosclerosis was found in <em>1</em>7<em>2</em> patients. Patients with early renal failure were significantly older and had significantly greater values of blood pressure, plasma fibrinogen, F<em>1</em>+<em>2</em>, and D-dimer than patients with normal renal function. Elevated D-dimer and fibrinogen levels were independently associated with the presence of decreased creatinine clearance. Log fibrinogen, log F<em>1</em>+<em>2</em>, and log D-dimer were inversely correlated with creatinine clearance. The prevalence of coronary artery, cerebrovascular, and peripheral vascular disease was significantly greater in patients with mild renal failure than in those with normal renal function. Elevated levels of fibrinogen and D-dimer were associated with the presence of atherosclerotic disease independent of renal function and other risk factors. In conclusion, changes in hemostatic parameters occur early in the course of renal failure in patients with arteriolar nephrosclerosis, suggesting a prothrombotic state that may contribute to the risk for atherosclerotic disease at all levels of renal function.

BACKGROUND

C1 inhibitor (C1-INH) is an alpha2-globulin that blocks esterolytic activity of the first component of the classic complement cascade. The alpha-granules of normal human platelets also contain C1-INH, which is expressed on the platelet surface during platelet secretion in healthy patients, but it is clearly reduced in patients with hereditary angioedema (HAE).

OBJECTIVE

To evaluate the effects of in vivo C1-INH concentrate infusion on platelet responsiveness and coagulation system activity in patients with HAE.

METHODS

Assessment of the platelet activity and plasma levels of C1-INH, activated factor XII (XIIa), and prothrombin fragment F1.2 (F1.2) before and after infusion of 15 U/kg of C1-INH concentrate.

METHODS

In 6 patients (4 men and 2 women), HAE was diagnosed according to the accepted clinical and laboratory criteria.

METHODS

Platelet aggregation (final concentrations: adenosine diphosphate, 0.5, 1.25, and 2.5 microM; collagen, 5 microg/mL), C1-INH antigen (radial immunodiffusion), C1-INH activity (chromogenic substrates), and XIIa and F1.2 (enzyme-linked immunosorbent assay).

RESULTS

After C1-INH infusion, we observed a prompt increase of C1-INH level and a slow return toward its plasma preinfusion values within 4 to 7 days, a significant decrease of both adenosine diphosphate- and collagen-induced platelet aggregation versus preinfusion values (maximum after 1-2 days; P <.001), and a rapid decrease of high basal values of XIIa and F1.2 in 30 and 120 minutes, respectively.

CONCLUSIONS

These data show a role of C1-INH in the control of platelet activity and that its deficiency increases platelet aggregability and plasma levels of XIIa and F1.2 in patients with HAE.

It has been suggested that increased erythrocyte membrane phosphatidylserine (PS) exposure could contribute to hypercoagulability and hemorheological disturbances in obesity. The aim of our study was to evaluate PS exposure in obese patients and in a control group and to correlate this with hemorheological properties, i.e., erythrocyte aggregability (EA) and deformability, and to evaluate the effect of weight loss on these parameters. An anthropometric and analytical evaluation was performed at baseline and after 3 months on a diet (very low-calorie diet for 4 weeks and low-calorie diet for <em>2</em> months) on 49 severe or morbid obese patients (37 women, <em>1</em><em>2</em> men) and 55 healthy volunteers (39 women, <em>1</em>6 men). PS exposure on erythrocyte membrane was performed by flow cytometry. Erythrocyte aggregation was measured using the Myrenne MA(<em>1</em>) and the Sefam aggregometer. Erythrocyte deformability was determined in a stress diffractometer. <em>Prothrombin</em> <em>fragment</em> F<em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>) was determined as a marker of the hypercoagulable state, and plasma malondialdehyde (MDA) as an indicator of oxidative stress. Obese patients had a higher EA index, higher PS exposure on erythrocyte membranes and higher levels of MDA and F<em>1</em>+<em>2</em>. The differences in erythrocyte aggregation and F<em>1</em>+<em>2</em> between obese patients and the control group were maintained after adjusting for PS exposure. After 3 months of diet, a significant reduction in PS exposure on erythrocyte membrane was observed. Obese patients show increased PS exposure on erythrocyte membrane, with no effect on rheological properties. Increased PS exposure could contribute to hypercoagulability in these patients. Weight loss obtained with diet treatment reduces PS exposure on erythrocyte membrane.

The hypothesis that <em>prothrombin</em> (FII) protects coagulation factor Va (FVa) from proteolytic inactivation by activated protein C (APC) was tested using purified proteins. FII dose-dependently protected FVa from APC proteolysis under conditions where competition of proteins for binding to negatively-charged phospholipid surface was not relevant (i.e. either at high phospholipid vesicle concentrations or using soluble dicaproylphosphatidylserine at levels below its critical micellar concentration). Cleavages in FVa at both Arg(506) and Arg(306) by APC were inhibited by FII. FII did not alter the amidolytic activity of APC towards chromogenic oligopeptide substrates or inhibit FVIIIa inactivation by APC, implying that the FII-mediated protection of FVa from APC proteolysis was due to the ability of FII to inhibit protein-protein interactions between FVa and APC. FII also protected FVa from inactivation by Gla-domainless APC, ruling out a role for the APC Gla domain for these observations. To identify domains of FII responsible for the observed phenomenon, various forms or <em>fragments</em> of FII were employed. Biotin-Phe-ProArg-CMK-inhibited meizothrombin and fII-<em>fragment</em> <em>1</em>*<em>2</em> protected FVa from proteolysis by APC. In contrast, no significant protection of FVa from APC cleavage was observed for Gladomainless-FII, prethrombin-<em>1</em>, prethrombin-<em>2</em>, FII <em>fragment</em> <em>1</em> or active site inhibited-thrombin (DEGR-thrombin). Overall, these data demonstrate that the Gla domain of FII linked to kringle <em>1</em> and <em>2</em> is necessary for the ability of FII to protect FVa from APC cleavage and support the general concept that assembly of the FII activation complex (FXa*FVa*FII*lipid surface) protects FVa from APC inactivation so that the procoagulant, thrombin generating pathway can act unhindered by APC. Only following FII activation and dissociation of the FII Gla domain <em>fragments</em> from the FII-ase complex, can APC inactivate FVa and down-regulate thrombin generation.

OBJECTIVE

Thromboembolic complications are common in patients with cancer and represent the second cause of death in patients with overt malignant disease. The aim of this study was to investigate the activated protein C pathway in cancer.

METHODS

We studied the coagulation cascade, natural clotting inhibitors, fibrinolytic proteins and resistance to activated protein C in <em>2</em>0 patients with advanced gastrointestinal cancer and 84 volunteers by measuring PT, APTT, fibrinogen, AT III, PC, PS, APC resistance, fibrinolytic system (PLG, ANPL, PAI-<em>1</em>, and t-PA) and activation peptides (D-Dimers, <em>prothrombin</em> 0 <em>fragment</em> <em>1</em> + <em>2</em>/F<em>1</em> + <em>2</em>).

RESULTS

Laboratory tests confirmed coagulation abnormalities in cancer patients. Fibrinogen, D-Dimers and F<em>1</em> + <em>2</em> were increased, while t-PA activity was significantly lower than that of controls. APC resistance was higher in cancer patients compared to the control group (55% vs <em>2</em>%; P < 0.000<em>1</em>). Excess thrombin generation was manifested by increased F<em>1</em> + <em>2</em> plasma levels in APC-resistant cancer patients. Genetic analyses showed that only one patient with a poor response to APC carried a factor V R506Q mutation in exon <em>1</em>0.

CONCLUSIONS

Our findings show a high prevalence of APC resistance in cancer, compatible with an acquired defect in the APC pathway.

Clotting activation may occur in liver cirrhosis, but the pathophysiological mechanism has not been fully elucidated. Because a previous study demonstrated that lipid peroxidation is increased in cirrhosis, we analyzed whether there is a relationship between lipid peroxidation and clotting activation. Thirty cirrhotic patients (<em>1</em>9 men and <em>1</em><em>1</em> women; age, 34 to 79 years) and 30 controls matched for sex and age were investigated. In all subjects, monocyte expression of tissue factor (TF) antigen and activity; plasma levels of <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>), a marker of thrombin generation; and urinary excretion of Isoprostane-F<em>2</em>alpha-III, a marker of lipid peroxidation, were measured. Furthermore, the above-reported variables were re-evaluated after 30 days of treatment with standard therapy (n = 5) or standard therapy plus 300 mg vitamin E twice daily (n = 9). In addition, we analyzed in vitro if vitamin E (50 micromol/L) influenced monocyte TF expression and F<em>1</em>+<em>2</em> generation. Cirrhotic patients had higher values of Isoprostane-F<em>2</em>alpha-III (P <. 000<em>1</em>), F<em>1</em>+<em>2</em> (P <.000<em>1</em>), and monocyte TF antigen (P <.000<em>1</em>) and activity (P <.03) than controls. Isoprostane-F<em>2</em>alpha-III was significantly correlated with F<em>1</em>+<em>2</em> (Rho = 0.85; P <.000<em>1</em>) and TF antigen (Rho = 0.95; P <.000<em>1</em>) and activity (Rho = 0.94; P <.000<em>1</em>). After vitamin E treatment, Isoprostane-F<em>2</em>alpha-III (P =.008), F<em>1</em>+<em>2</em> (P <.008), and monocyte TF antigen (P =.0<em>1</em><em>2</em>) and activity (P =.008) significantly decreased; no changes of these variables were detected in patients not receiving vitamin E. In vitro, vitamin E significantly reduced the expression of monocyte TF antigen (-5<em>2</em>%; P =.00<em>1</em>) and activity (-55%; P =.003), as well as F<em>1</em>+<em>2</em> generation (-5<em>1</em>%; P =.0<em>2</em>5). This study shows that vitamin E reduces both lipid peroxidation and clotting activation and suggests that lipid peroxidation may be an important mediator of clotting activation in liver cirrhosis.