We treated a 59-year-old woman presenting with hemoptysis, a rare symptom of pheochromocytoma. Multiple factors including hypertension caused by sudden catecholamine release may result in pulmonary edema. It should be noted that the increased activation of coagulation cascade, which was demonstrated by increased thrombin-antithrombin III complex (TAT) and <em>prothrombin</em> <em>fragment</em> factor <em>1</em> and <em>2</em> (F<em>1</em> + <em>2</em>), as well as endothelial or platelet stimulation evidenced by the increased plasma von Willebrand factor, may have contributed to hemoptysis. These abnormalities were normalized after adrenalectomy. Our case indicates the important role of catecholamine in coagulopathy and possibly in vasculopathy.

This study aimed to estimate the diagnostic utility of biomarkers for suspected venous thromboembolism (VTE) in pregnancy and the puerperium. Research nurses/midwives collected blood samples from 3<em>1</em>0 pregnant/postpartum women with suspected pulmonary emboli (PE) and <em>1</em>8 with diagnosed deep vein thrombosis (DVT). VTE was diagnosed using imaging, treatment and adverse outcome data. Primary analysis was limited to women with conclusive imaging (36 with VTE, <em>2</em>47 without). The area under the curve (AUC) for each biomarker was: activated partial thromboplastin time 0·669 (95% confidence interval 0·570-0·768), B-type natriuretic peptide 0·549 (0·453-0·645), C-reactive protein 0·54<em>2</em> (0·445-0·639), Clauss fibrinogen 0·589 (0·476-0·70<em>1</em>), D-Dimer (by enzyme-linked immunosorbent assay) 0·668 (0·56<em>1</em>-0·776), near-patient D-Dimer 0·65<em>1</em> (0·545-0·758), mid-regional pro-atrial natriuretic peptide 0·5<em>2</em>4 (0·4<em>1</em>8-0·630), <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> 0·56<em>2</em> (0·46<em>2</em>-0·66<em>1</em>), plasmin-antiplasmin complexes 0·639 (0·536-0·74<em>2</em>), prothombin time 0·6<em>1</em>3 (0·508-0·7<em>1</em>8), thrombin generation lag time 0·70<em>2</em> (0·598-0·806), thrombin generation endogenous potential 0·559 (0·437-0·68<em>1</em>), thrombin generation peak 0·596 (0·478-0·7<em>1</em>5), thrombin generation time to peak 0·655 (0·54<em>1</em>-0·769), soluble tissue factor 0·53<em>1</em> (0·4<em>2</em>4-0·638) and serum troponin 0·597 (0·499-0·695). No diagnostically useful threshold for diagnosing or ruling out VTE was identified. In pregnancy and the puerperium, conventional and candidate biomarkers have no utility either for their negative or positive predictive value in the diagnosis of VTE.

BACKGROUND

Patients with acute ischemic stroke and atrial fibrillation are at increased risk of stroke progression and recurrence. We sought to assess whether D-dimer and other markers of hemostatic activation could predict these adverse events in such patients.

METHODS

Blood samples were obtained from patients included in the Heparin in Acute Embolic Stroke Trial. Stroke progression was defined as a ≥3-point worsening on the Scandinavian Stroke Scale during the first 48 h after randomization. Blood samples were analyzed for D-dimer, <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>, soluble fibrin monomer, and C-reactive protein.

RESULTS

A total of 38<em>2</em> patients were included in the analyses. Levels of D-dimer and other markers of hemostatic activation were not significantly higher in patients with stroke progression than in other patients (D-dimer median values: <em>1</em>0<em>2</em>5 ng/ml vs 970 ng/ml, P = 0.73). The same was true for recurrent stroke (D-dimer: 7<em>2</em>0 ng/ml vs 973 ng/ml, P = 0.96), and the combined endpoint of stroke progression, recurrent stroke, and death (D-dimer: 99<em>1</em> ng/ml vs 970 ng/ml, P = 0.9<em>1</em>). Multivariable analyses did not alter the results.

CONCLUSIONS

D-dimer and other markers of hemostatic activation were not associated with stroke progression, recurrent stroke, or death in patients with acute ischemic stroke and atrial fibrillation.

Recent clinical studies comparing accelerated versus bolus administration of alteplase tissue plasminogen activator (t-PA) suggest similar thrombolytic efficacy, but reveal higher bleeding complications among older patients during the double-bolus regimen. The objective of the present study was to characterize the hemostatic profile of t-PA administered as double-bolus doses of 50 mg, at intervals of 30 minutes. Among 50 patients with acute myocardial infarction treated by double-bolus t-PA thrombolysis, coagulation and fibrinolysis parameters, as well as t-PA levels, were monitored. Monitored t-PA levels peaked at 5 and 35 minutes and were detectable within the therapeutic range even after 90 minutes. Marked systemic fibrinolytic activation was indicated by 75% depletion of both plasminogen and fibrinogen, as well as by <em>1</em>9-fold and 300-fold increases of fibrin degradation and fibrinogen degradation products. Plasminogen-activator inhibitor activity was completely suppressed. Pronounced procoagulant activation was reflected by a 3.4-fold increase of both factor XIIa and <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, and by a threefold increase of thrombin-antithrombin complex. Independent of t-PA weight dosage, fibrinolytic activation was more pronounced among older patients >> or = 63 years). We conclude that t-PA after bolus administration has a long half-life. Double-bolus regimen leads to a long-lasting systemic fibrinolytic state, which is even more remarkable among older patients--a fact that may explain the higher bleeding complications reported for this age group.

BACKGROUND

Hormone replacement therapy is known to increase the risk of thromboembolic events. We compared the effects of HRT and raloxifene on some haemostasis variables.

METHODS

In a multicenter, double-blind study, 54 healthy postmenopausal women were randomized to receive either continuous treatment with <em>2</em> mg <em>1</em>7beta-estradiol plus <em>1</em> mg norethisterone acetate (n=30) or 60 mg raloxifene (n=<em>2</em>4) daily for <em>1</em><em>2</em> months. Blood samples were collected at baseline and at 3, 6 and <em>1</em><em>2</em> months to evaluate therapy effects on some haemostasis variables (factor VII, factor VIII, <em>prothrombin</em> <em>fragments</em> <em>1</em> and <em>2</em>, protein C, protein C activity, protein S, thrombin-antithrombin complex, D-dimer, antithrombin, fibrinogen and plasminogen activator inhibitor).

RESULTS

Both raloxifene and continuous combined hormone therapy modified the haemostasis variables toward a more prothrombotic profile. Factor VIII (p<0.0<em>1</em>) and fibrinogen (p<0.05) plasma levels significantly increased at 6 months, <em>prothrombin</em> <em>fragments</em> <em>1</em> and <em>2</em> (p<0.05) significantly increased at <em>1</em><em>2</em> months, whereas protein C activity (p<0.00<em>1</em>) and antithrombin (p<0.0<em>1</em>) significantly decreased at <em>1</em><em>2</em> months in both groups.

CONCLUSIONS

Our results demonstrate that raloxifene and continuous combined hormone therapy exhibit the same prothrombotic profile. Both treatments induced an increase in procoagulant parameters at 6 months and a decrease in anticoagulant parameters at <em>1</em><em>2</em> months.

BACKGROUND

Edoxaban (the free base of DU-<em>1</em>76b) is a new, oral direct Factor Xa inhibitor. This is the first study to compare the hemostatic response to edoxaban, ximelagatran, and dalteparin in healthy, elderly adults.

METHODS

In this open-label, active-controlled clinical trial, 40 adults (65-75 years), were randomised to: oral edoxaban (60 mg, twice-daily, 7 doses), subcutaneous dalteparin (5000 IU, once-daily, 4 doses), oral ximelagatran (<em>2</em>4 mg, twice-daily, 7 doses) or no drug. Blood samples were taken before, and <em>1</em>.5, 4, <em>1</em><em>2</em>, <em>2</em>4, 7<em>2</em>, 84, 96, <em>1</em>08, <em>1</em><em>2</em>0, and <em>1</em>44 hours after, the first dose. The primary outcomes were changes in thrombin-antithrombin complex, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> and D-dimer, and adverse events. Additional biomarkers of coagulation, and endothelial cell and platelet activation were compared (ANOVA).

RESULTS

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

CONCLUSIONS

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

BACKGROUND

Daiichi Sankyo Pharma Development.

BACKGROUND

Overt proteinuria is a strong risk factor for thromboembolism, owing to changes in the levels of various coagulation proteins and urinary antithrombin loss. The described coagulation disturbances in these patients are based on outdated studies conducted primarily in the <em>1</em>970s and <em>1</em>980s. Whether these coagulation disturbances resolve with antiproteinuric therapy has yet to be studied.

METHODS

A total of 3<em>2</em> patients with overt proteinuria (median, 3.7 g day(-<em>1</em>) ; interquartile range, <em>1</em>.5-5.6) were enrolled in this intervention crossover trial designed to assess optimal antiproteinuric therapy with sodium restriction, losartan, and diuretics. Levels of various procoagulant and anticoagulant proteins, and parameters of two thrombin generation assays (calibrated automated thrombogram [CAT] and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>) were compared between the placebo period and the maximum antiproteinuric treatment period. As a secondary analysis, coagulation measurements of the placebo period in these patients were compared with those of 3<em>2</em> age-matched and sex-matched healthy controls.

RESULTS

Median proteinuria was significantly lower during the maximum treatment period (median, 0.9 g day(-<em>1</em>) ; interquartile range, 0.6-<em>1</em>.4; P < 0.00<em>1</em>) than during the placebo period. Similarly, levels of various liver-synthesized procoagulant and anticoagulant proteins, activated protein C resistance and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> levels were significantly lower during the maximum treatment period than during the placebo period. However, von Willebrand factor and factor VIII levels were similar. On the basis of the higher levels of procoagulant proteins (fibrinogen, FV, FVIII, and von Willebrand factor) and both thrombin generation assays, patients were substantially more prothrombotic than healthy controls (P < 0.004).

CONCLUSIONS

Antiproteinuric therapy ameliorates the prothrombotic state. Proteinuric patients are in a more prothrombotic state than healthy controls.

In order to study the effect of different intensities of anti-vitamin K treatment on coagulation parameters, <em>2</em>3 patients with venous thromboembolism were given, after the initial treatment period, warfarin at doses giving an International Normalised Ratio of <em>1</em>.3-<em>2</em>.0 for 4 weeks, and of <em>1</em>.<em>1</em>-<em>1</em>.3 for another 4 weeks. Blood samples were taken at the end of each of these periods and 4 weeks after the end of warfarin treatment. The vitamin K-dependent coagulation factors VII, IX, and X, as well as the inhibitor protein C and its cofactor protein S, all showed a highly significant correlation with treatment intensity. This was to some extent also true for the coagulation activation markers, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> and thrombin-antithrombin complex. Ratios of pro- and anticoagulant factors in some instances showed a decrease at therapeutical (International Normalised Ratio) levels, and also sometimes with reduced warfarin treatment intensity. Taken together, our results encourage further research addressing issues of varying treatment intensity with warfarin and alternative methods for monitoring of anti-vitamin K treatment.

OBJECTIVE

To assess the efficacy of a fixed, low dose of warfarin in lowering factor VII coagulant activity (FVII:C) and to investigate the effects on the plasma coagulation cascade.

METHODS

An open pilot study with two dose levels of warfarin: <em>1</em>.<em>2</em>5 and <em>2</em>.5 mg day-<em>1</em> during two consecutive 4-week periods. All subjects received aspirin 75 mg day-<em>1</em>. <em>Prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F(<em>1</em> + <em>2</em>)), protein C, protein S, FVII:C, factor X and P-<em>prothrombin</em> complex activity (P-PT) were measured at baseline, at <em>2</em>-week intervals and 4 weeks after end of treatment. Coagulation activation peptide F(<em>1</em> + <em>2</em>) was used as a marker of thrombin formation.

METHODS

Twelve male patients with a history of myocardial infarction. Inclusion was made through a written questionnaire.

RESULTS

Warfarin <em>1</em>.<em>2</em>5 mg day-<em>1</em> lowered FVII:C from <em>1</em><em>1</em>3 U dl-<em>1</em> to <em>1</em>07 U dl-<em>1</em> (P = 0.0<em>2</em>5) and F(<em>1</em> + <em>2</em>) from <em>1</em>.60 nmol l-<em>1</em> to <em>1</em>.<em>2</em>7 nmol l-<em>1</em> (P = 0.0<em>1</em>3) but had no effect on protein C or P-PT. A dose of <em>2</em>.5 mg day-<em>1</em> induced further lowering of FVII:C (9<em>1</em> U dl-<em>1</em>, P = 0.004<em>2</em>), and also of protein C from <em>1</em><em>1</em>6% to 99% (P = 0.034) and P-PT from <em>1</em>07% to 8<em>1</em>% (P = 0.0096) mean values.

CONCLUSIONS

Warfarin <em>1</em>.<em>2</em>5 mg day-<em>1</em> seems to exert an anticoagulant effect without reduction in PT or the natural anticoagulant protein C and is suggested, in combination with aspirin, to be a safe and simple therapy against arterial thrombotic disease, making regular PT controls unnecessary.

OBJECTIVE

Visfatin is an adipocytokine that has recently generated much interest. The aim of the study was to assess visfatin in correlation with markers of endothelial damage and inflammation in haemodialyzed and peritoneally dialyzed patients.

METHODS

Visfatin, leptin, apelin and adiponectin, markers of coagulation (thrombin-antithrombin complexes (TAT), <em>prothrombin</em> <em>fragments</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>)), fibrinolysis (tissue plasminogen activator (tPA), plasminogen activator inhibitor type <em>1</em> (PAI-<em>1</em>)), endothelial function/injury (Von Willebrand factor (vWF), thrombomodulin, intracellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), CD<em>1</em>46) and inflammation (high-sensitivity C-reactive protein (hsCRP), tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6) were assessed.

RESULTS

Triglycerides, hsCRP, creatinine, IL-6, TNF-alpha, vWF, F<em>1</em>+<em>2</em>, TAT, thrombomodulin, ICAM, VCAM, CD<em>1</em>46, PAI-<em>1</em>, leptin, adiponectin and visfatin were elevated in dialyzed patients over controls. Visfatin correlated significantly, in univariate analysis, in haemodialyzed patients with markers of endothelial damage/inflammation (CD<em>1</em>46, ICAM, IL-6), other adipocytokines, Kt/V and dialysis vintage, and tended to correlate with hsCRP. In peritoneally dialyzed patients, visfatin correlated significantly with haemoglobin, and markers of endothelial damage. In the healthy volunteers visfatin correlated significantly with ICAM, creatinine and IL-6. In multiple regression analysis in HD patients visfatin was only independently related to Kt/V, dialysis vintage and IL-6.

CONCLUSIONS

Elevated visfatin related to markers of inflammation might represent a novel link between inflammation and adipocytokines in dialyzed patients. Time on dialyses and dialysis adequacy may influence visfatin in dialyzed patients due to the decreased clearance of visfatin.

Upon addition of calcium to the metal-free protein, bovine <em>prothrombin</em> displays a conformational change with behavior of a classic trans- to cis-proline isomerization. The change is accompanied by a decrease of the intrinsic protein fluorescence and is essential to creating the membrane-binding conformation of <em>prothrombin</em>. This study showed that an identical conformational change was displayed by a peptide corresponding to residues <em>1</em>-45 of <em>prothrombin</em>. This peptide contains a single tryptophan that underwent extensive quenching upon calcium addition. The kinetics were slow (t<em>1</em>/<em>2</em> = <em>2</em>.7 min at <em>2</em>4 degrees C) and displayed an activation energy of <em>2</em>4 kcal/mol. These properties overlapped precisely with the behavior of bovine <em>prothrombin</em> <em>fragment</em> <em>1</em> (residues <em>1</em>-<em>1</em>56). Consistent with studies on <em>prothrombin</em> and other vitamin K-dependent proteins that have been modified or truncated, the <em>1</em>-45 peptide required about <em>1</em>0-fold higher calcium to elicit these behaviors than did <em>fragment</em> <em>1</em>. The conformational change was necessary for membrane binding by the <em>1</em>-45 peptide. The only proline in this sequence is at position <em>2</em><em>2</em>. This proline is of the trans configuration in a crystallized form of calcium-bovine <em>prothrombin</em> <em>fragment</em> <em>1</em> [Soriano-Garcia, M., et al. (<em>1</em>99<em>2</em>) Biochemistry 3<em>1</em>, <em>2</em>554]. Unless the protein conformational change is based on another behavior, this study showed that biochemical properties of the protein are inconsistent with structure solutions. Further studies are needed to reconcile structure/function in membrane association. Proline <em>2</em><em>2</em> in bovine <em>prothrombin</em> may constitute a useful biochemical marker for the membrane-binding conformation of a vitamin K-dependent protein.

Patients with end-stage renal disease are prone to hemorrhagic complications and simultaneously are at risk for a variety of thrombotic complications such as thrombosis of dialysis blood access, the subclavian vein, coronary arteries, cerebral vessel, and retinal veins, as well as priapism. The study was devised for the following purposes: (<em>1</em>) to identify the markers of thrombophilia in hemodialyzed patients, (<em>2</em>) to establish a role for antiphospholipid antibodies in thrombosis of the vascular access, (3) to characterize phospholipid antibodies in hemodialysis patients, and (4) to study the effects of dialysis on coagulation cascade. A group of <em>2</em>0 hemodialysis patients with no thrombotic complications (NTC) and <em>2</em>0 hemodialysis patients with thrombotic complications (TC) were studied along with 400 volunteer blood donors. Patients with systemic lupus erythematosus and those with nephrotic syndrome were excluded. All patients underwent a screening <em>prothrombin</em> time, activated partial thromboplastin time, fibrinogen (Fg), coagulation factors of the intrinsic and extrinsic pathways, antithrombin III (AT-III), protein C (PC), protein S (PS), resistance to activated protein C, <em>prothrombin</em> activation <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>), plasminogen, tissue type plasminogen activator (t-PA), plasminogen tissue activator inhibitor type-<em>1</em> (PAI-<em>1</em>), anticardiolipin antibodies type M and G (ACA-IgM and ACA-IgG), lupus anticoagulant antibodies, and anti<em>prothrombin</em> antibodies type M and G (aPT-IgM and aPT-IgG). The study showed that PAI-<em>1</em>, F <em>1</em>+<em>2</em>, factor VIII, ACA-IgM, and aPT-IgM levels were increased significantly over controls both in TC and NTC, however, they could distinguish patients with thrombotic complications from those without, being increased maximally in the former group. The novelty of the study is represented by the significant aPT increase that was observed in non-systemic lupus erythematosus hemodialysis patients, and particularly in those with thrombotic events. In addition, there was a reduction of factor XII during the treatment. It is possible to assume in the TC group and, to a lesser extent, also in the NTC group that endothelial cells liberate PAI-<em>1</em> in the vascular lumen, which causes hypofibrinolysis. In addition, an excess of factor VIII is activated by endothelial dysfunction with subsequent activation of the coagulation cascade as shown by increased F<em>1</em>+<em>2</em> and fibrinogen. ACA-IgM, in turn, is capable of interfering with the system of protein C, a potent anticoagulant factor that inactivates cofactors Va and VIIIa. They also induce the expression of procoagulant factors on the surface of the endothelial cells. In conclusion, the hypercoagulable state caused by alterations of coagulation and fibrinolytic factors is a cause of vascular access dysfunction and thrombosis of other vessels.

OBJECTIVE

Almost a third of patients who undergo peripheral bypass procedures do not have suitable veins, making the use of prosthetic materials necessary. Prosthetic materials can cause platelet adhesion and activation of the coagulation cascade on the graft. One potential strategy to reduce this thrombogenicity is to covalently bind heparin to the endoluminal surface of grafts. This human in vivo study examined systemic effects of the endoluminal heparin and addressed whether graft implantation results in (<em>1</em>) a measurable reduction of systemic markers of hemostasis activation compared with control grafts and (<em>2</em>) antibody formation against heparin, potentially responsible for heparin-induced thrombocytopenia (HIT).

METHODS

The study included <em>2</em>0 patients undergoing femoropopliteal bypass grafting, of whom <em>1</em>0 received a standard Gore-Tex Thin Walled Stretch Vascular Graft (W. L. Gore & Associates, Flagstaff, Ariz) and <em>1</em>0 received a heparin-bonded expanded polytetrafluoroethylene (ePTFE) graft (Gore-Tex Propaten Vascular Graft). Blood samples were drawn before and directly after the operation and at days <em>1</em>, 3, 5, and week 6 after surgery. Established markers of in vivo activation of platelets and blood coagulation (<em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, fibrinopeptide A, soluble glycoprotein V, thrombin-antithrombin complexes, and D-dimers) were measured using standard commercially available techniques. Antiplatelet factor 4/heparin antibody titers were measured using a commercially available enzyme-linked immunosorbent assay, and platelet counts were determined.

RESULTS

No statistical differences were observed in any of the markers of in vivo activation of platelets and blood coagulation between patients receiving Propaten or control ePTFE. Moreover, no antibodies against heparin could be demonstrated up to 6 weeks after implantation.

CONCLUSIONS

No measurable effect of heparin immobilization on systemic markers of hemostasis was found using a heparin-bonded ePTFE graft in vivo. Also, no antibodies against heparin could be detected up to 6 weeks after implantation.

Hirudin serves as an alternative anticoagulant for extracorporeal blood circulation. Comparing anticoagulation with hirudin (<em>2</em>.5 or 5.0 microg/mL) and heparin (<em>2</em>.0 or 4.0 IU/mL) human blood was circulated in a modified 'Chandler System' using PVC-tubes for <em>2</em> hours at 37 degrees C. Activation of coagulation (thrombin-antithrombin III-complex, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> and D-Dimer), platelet (platelet factor 4 - PF4) and complement systems was analyzed. Both heparin concentrations and 5.0 microg/dL hirudin led to as significantly less activated plasmatic coagulation as <em>2</em>.5 microg/dL hirudin. Decreased levels of PF4 and anaphylatoxin C5a (p<0.05) as well as terminal complement complex demonstrated improved hemocompatibility after anticoagulation with heparin in contrast to hirudin. Because initial coagulation cascade, platelet activation and complement activation is less influenced by hirudin than by heparin, hemocompatibility is more dependent on the characteristics of the biomaterials used. This predestines hirudin as anticoagulant for in vitro studies analyzing hemocompatibility of biomaterials or surface modifications.

BACKGROUND

Small-diameter vascular grafts tend to have an early and high occlusion rate. Cell seeding on the luminal surfaces of small-diameter vascular prostheses may provide an antithrombotic lining and improve both the short-term and the long-term patency rates. We studied the net results of procoagulant and anticoagulant properties of seeded grafts under blood-flow conditions, and we compared the different available types of donor cells.

METHODS

Monolayers of liposuction-derived cultured human microvascular endothelial cells (MVECs), human adult endothelial cells (HAECs), human umbilical vein endothelial cells (HUVECs), and human mesothelial cells (MCs) that had been seeded on expanded polytetrafluoroethylene (ePTFE) grafts were perfused with marginally anticoagulated blood (<em>2</em>0 U/mL low molecular weight heparin; shear rate, 400/s, <em>1</em>0 minutes) or with non-anticoagulated blood (shear rate, <em>1</em>00/s, 5 minutes). The thrombin and fibrin generation in time was studied with the measurement of the plasma levels of <em>prothrombin</em> <em>fragment</em> <em>1</em> and <em>2</em> (F <em>1</em>+<em>2</em>) and of fibrinopeptide A (FPA). The plain ePTFE graft was taken as a control.

RESULTS

When the seeded MCs were perfused with recirculating anticoagulated blood, a linear generation of F <em>1</em>+<em>2</em> in time was seen, with high levels of F <em>1</em>+<em>2</em> and FPA after <em>1</em>0 minutes (4.38 nmol/L and 36<em>2</em> ng/mL, respectively). Allopurinol was added, and the MCs generated less F <em>1</em>+<em>2</em> than the HAECs (0.7 nmol/L vs <em>1</em>.86 nmol/L; P <.05). No fibrin formation was seen. The MVECs generated low amounts of F <em>1</em>+<em>2</em> (0.7 nmol/L; <em>1</em>0 minutes), and the HUVECs and the plain ePTFE graft generated the lowest amounts of F <em>1</em>+<em>2</em> (0.<em>2</em>6 and 0.<em>2</em>5 nmol/L, respectively). When the MCs were perfused with non-anticoagulated blood, high amounts of thrombin and fibrin were generated immediately and constantly and could not be decreased with allopurinol. The perfusion of the plain ePTFE graft showed a dramatic increase in F <em>1</em>+<em>2</em> and FPA levels towards the end of the experiments. The seeded HAECs, HUVECs, and MVECs inhibited this increase. These results were confirmed by means of scanning electron microscopy.

CONCLUSIONS

Vascular prostheses that are seeded with cultured MCs are highly procoagulant. Standard ePTFE graft prostheses also initiate coagulation, which supports the idea of cell seeding. The endothelial cells, of which the MVECs are the most readily available, seem to preserve their anticoagulant properties after being seeded on vascular grafts.

Essentials FXaI<em>1</em>6L is a recombinant zymogen-like variant of activated coagulation factor X (FXa). A phase <em>1</em> dose escalation clinical trial of FXaI<em>1</em>6L was conducted in healthy adults. FXaI<em>1</em>6L was safe and tolerated at doses up to 5 μg/kg; no dose-limiting toxicity was observed. Data support further development of FXaI<em>1</em>6L for patients with acute hemorrhagic conditions.

Background FXaI<em>1</em>6L (PF-05<em>2</em>30907) is a zymogen-like variant of activated factor X (FXa). It shows enhanced resistance to inactivation by endogenous inhibitors as compared with wild-type FXa, and restores hemostatic activity in non-clinical models of various bleeding conditions. Objectives To evaluate the safety, pharmacokinetics and pharmacodynamics of FXaI<em>1</em>6L by performing a phase <em>1</em>, first-in-human, dose-escalation clinical trial in healthy adult volunteers. Methods Participants were assigned to one of six ascending single-dose cohorts (0.<em>1</em>, 0.3, <em>1</em>, <em>2</em>, 3 or 5 μg kg-<em>1</em> ), each planned to comprise six volunteers treated with FXaI<em>1</em>6L and two treated with placebo. Assessments included safety monitoring, pharmacokinetic and pharmacodynamic (PD) analyses, and immunogenicity testing. Results The trial enrolled 49 male volunteers. Administration of a single intravenous bolus dose of FXaI<em>1</em>6L was safe and tolerated at all dose levels tested, with no dose-limiting toxicity or serious adverse events. FXaI<em>1</em>6L plasma levels appeared to increase dose-proportionally, with a half-life of ~ 4 min. Treatment-related PD changes were observed for activated partial thromboplastin time, thrombin generation assay, thrombin-antithrombin complexes, <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>, and D-dimer. One volunteer had a weak and transient non-neutralizing antidrug antibody response, which did not cross-react with native FX or native FXa. Conclusions FXaI<em>1</em>6L was safe and tolerated, and showed a pharmacologic effect in healthy adults when administered at doses up to 5 μg kg-<em>1</em> . The safety profile, pharmacokinetics and pharmacodynamics observed in this clinical trial support the further development of FXaI<em>1</em>6L for hemostatic treatment in individuals with acute hemorrhagic conditions.

BACKGROUND

The occurrence of coagulation system alterations after bone marrow transplantation (BMT) and their possible role in the pathogenesis of thrombotic complications such as veno-occlusive disease of the liver (VOD) are still a matter of debate. The aim of this study was to evaluate prospectively the alterations in hemostatic balance developing during the early period after BMT (up to day +<em>2</em><em>1</em>) and their relationships (if any) with VOD.

RESULTS

Twenty-nine patients (<em>1</em>5 autologous and <em>1</em>4 allogeneic BMT) entered the study. No patient suffered from thrombotic and/or major hemorrhagic events. Since there were no differences between the two groups of patients with regard to modifications of coagulation parameters, they were considered together for the purposes of the study. We observed a progressive increase from baseline levels of fibrinogen, factor VIII activity (fVIII:C) and von Willebrand factor antigen (vWf), while factor VII antigen (fVIIAg), protein C and plasminogen significantly decreased. The alterations in these test values were maximal on day +<em>1</em>4, with a trend towards normal levels one week later. There was no modification of PT, PTT, <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F <em>1</em> + <em>2</em>), fXIIC, tPA, PAI-<em>1</em>, D dimer or protein S levels; serum levels of tumor necrosis factor-alpha were also unchanged.

CONCLUSIONS

These results suggest that some alterations of the hemostatic system, probably a consequence of endothelial damage, can be detected early after BMT, but their clinical significance remains uncertain due to the lack of a correlation between hemostatic test alterations and the occurrence of thrombotic complications.

There is a close interrelation between cancer and haemostasis, which is characterized by changes in the haemostatic system, mostly an activation of coagulation in cancer patients. Venous thromboembolism (VTE) is a frequent complication of cancer and in particular of anticancer therapy and is associated with significant morbidity and mortality. As the occurrence of VTE in cancer patients is a life-threatening condition, clinical parameters or laboratory tests predictive of VTE might be helpful for early identification of patients at high or low risk of VTE in order to allow a tailored therapy assessment. Recently, some candidate laboratory parameters or biomarkers, such as blood count, P-selectin, D-Dimer, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, clotting factor VIII and tissue factor, have been identified as predictors of the VTE risk in cancer. Interventional trials based on risk assessment with the use of biomarkers or risk scoring models are needed to demonstrate effectiveness and safety of tailored thromboprophylaxis.

In this study, protein C (PC), protein S (PS), heparin cofactor II (HCFII), <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (PF <em>1</em>,<em>2</em>), thrombin-antithrombin III complex (TAT), von Willebrand factor (vWF) and thrombomodulin (TM) were investigated in <em>1</em>9 patients with acute lymphoblastic leukemia, (ALL) receiving combined chemotherapy including L-asparaginase (L-ASP) and high dose methylprednisolone (HDMP). HDMP was administered in doses of 30 mg/kg/day for 7 days, and <em>2</em>0 mg/kg/day for another 7 days. In order to evaluate the effect of HDMP on the hemostatic system, the 8 patients studied here received HDMP (30 mg/kg/day) therapy for 4 days before the combined chemotherapy. These parameters were also studied in <em>1</em><em>2</em> healthy children as a control group. PC levels were normal in the patients while PS levels were decreased both before and after combined chemotherapies. Patients with ALL have laboratory signs of coagulation activation such as PF <em>1</em>,<em>2</em>, TAT prior to initiation of chemotherapy. With combined chemotherapy, TAT levels were found to be normal while PF<em>1</em>,<em>2</em> were not. TM levels were found to be increased both before and after therapies whereas HCFII and vWF levels were not different from those of the control group. The short course of HDMP therapy did not prominently influence these hemostatic parameters. These results indicate that both the malignant process and the drugs used in combined chemotherapy cause a decrease in natural inhibitors and an increase in procoagulant activity and endothelial injury. These hemostatic changes may contribute to a thrombotic tendency in the patients with ALL.

BACKGROUND

Cold preservation, reperfusion damage, immunosuppressive drugs, and uremia-induced acquired thrombophilias increase the risk of thrombotic complications in renal transplantation. Intragraft fibrin deposition may be associated with delayed graft function.

METHODS

We studied coagulation and fibrinolysis in 45 patients of a larger trial in renal transplantation: perioperative antithymocyte globulin (group A, n=<em>1</em>5), perioperative basiliximab (group B, n=<em>1</em>6), and conventional triple therapy (group C, n=<em>1</em>4). Blood samples for <em>prothrombin</em> <em>fragment</em> F<em>1</em>+<em>2</em>, plasminogen activator inhibitor (PAI)-<em>1</em>, d-dimer, tPA antigen, tPA activity, and platelet counts were obtained simultaneously at <em>1</em> and 5 min after reperfusion from iliac artery and graft vein for calculation of transrenal changes. Because antithymocyte globulin activates coagulation and fibrinolysis, group A was analyzed separately. Groups B and C were pooled (group BC).

RESULTS

In group BC, transrenal D-dimer release occurred at <em>1</em> min, tPA-antigen release at <em>1</em> and 5 min, and transrenal PAI-<em>1</em> uptake at 5 min postreperfusion. tPA activity increased marginally only at <em>1</em> min. High graft tPA-antigen release at 5 min and D-dimer release at <em>1</em> min were associated with delayed graft function. In group A, transrenal tPA-antigen release occurred at <em>1</em> and 5 min and D-dimer release at <em>1</em> min. There were no transrenal F<em>1</em>+<em>2</em> changes in either group.

CONCLUSIONS

Although graft PAI-<em>1</em> uptake inhibits tPA activity, graft releases D-dimer at early reperfusion without concomitant F<em>1</em>+<em>2</em> release. Data suggest thrombin and fibrin formation already before cold preservation during donor care and organ retrieval. This fibrin deposition increases risk of delayed graft function.

We investigated the possibility that despite postoperative derangements of routine laboratory coagulation tests, markers of coagulation activation and thrombin generation would be normal or increased in patients undergoing hepatic resection for cancer In addition to the conventional coagulation tests <em>prothrombin</em> time and activated partial thromboplastin time, we measured select markers of coagulation activation <em>prothrombin</em> <em>fragments</em> <em>1</em> and <em>2</em> (PF<em>1</em> + <em>2</em>), thrombin-antithrombin complexes and plasma von Willebrand Factor antigen in <em>2</em><em>1</em> patients undergoing hepatic resection. The impact of hepatic resection on coagulation and fibrinolysis was studied with thromboelastography. Preoperatively, routine laboratory coagulation and liver function tests were normal in all patients. On the first postoperative day, <em>prothrombin</em> time was prolonged (range <em>1</em>6 to <em>2</em><em>2</em> seconds) in eight patients (38%). For these patients, thromboelastography was normal in six (75%), PF<em>1</em> + <em>2</em> was elevated in four (50%), and thrombin-antithrombin complexes and von Willebrand Factor antigen were elevated in all, which was evidence of acute phase reaction, sustained coagulation factor turnover and activation. By the fifth postoperative day, despite normalisation of <em>prothrombin</em> time, markers of increased coagulation activity remained greater than 85% of baseline values. The findings indicate that in patients undergoing liver resection for cancer, there is significant and prolonged postoperative activation of the haemostatic system despite routine coagulation tests being normal or even prolonged. Before considering therapeutic interventions an integrated approach to interpreting haematological data with clinical correlation is essential.

Dietary fat is known to influence the variables of blood coagulation and fibrinolysis associated with vascular disease. However, the role of fat content and/or fat composition of the diet in this regard is still not well understood. In the present study, we investigated the effects of three isoenergic diets of differing fat composition in nine healthy young men in a strictly controlled residential study. Subjects consumed the three experimental diets for periods of <em>2</em> weeks each, separated by a washout period of at least 5 weeks in a randomized crossover design. The diets provided 38% of total energy intake as fat, 45% as carbohydrate, and <em>1</em>7% as protein, and differed only with respect to the fatty acid composition (stearic acid-rich diet: 34.<em>1</em>% stearic acid, 36.6% oleic acid; oleic acid-rich diet: 65.8% oleic acid; linoleic acid-rich diet: 36.5% linoleic acid, 38% oleic acid). Blood samples were collected at the beginning and at the end of each dietary period from fasted subjects for determination of factor VII coagulant activity (FVIIc), activated factor VII (FVIIa), factor VII antigen (FVIIag), tissue plasminogen activator (tPA) activity, plasminogen activator inhibitor type <em>1</em> (PAI-<em>1</em>) activity, fibrinogen, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F(<em>1</em>+<em>2</em>)), and plasma lipids. There were no significant differences between diets in fasting plasma concentrations of FVIIc, FVIIa, FVIIag, fibrinogen, F(<em>1</em>+<em>2</em>), PAI-<em>1</em> activity, and tPA activity. Plasma concentrations of lipids (high density lipoproteins, low density lipoproteins, triacylglycerols, and total cholesterol) were also unaffected. Although there were no changes in platelet aggregation response and membrane fluidity observed in any of the diets, increased anti-aggregatory prostaglandin E(<em>1</em>) binding to platelet membranes was observed only in the case of linoleic acid-rich diet. In conclusion, diets with very different fatty acid compositions, at 38% of energy as fat intake, did not significantly influence blood coagulation, fibrinolysis, or blood lipids in the fasting state in young healthy men.

BACKGROUND

In assessing Crohn's disease (CD) activity, C-reactive protein (CRP) is an important indicator of inflammation; however, it is not necessarily associated with the Crohn's Disease Activity Index (CDAI), particularly in patients with low CRP. Recently, platelet activation factors have been recognized due to their importance in the inflammatory response. In this study, we examined associations between the CDAI and platelet factor 4 (PF-4), β-thromboglobulin (β-TG), and other coagulation and fibrinolysis factors.

OBJECTIVE

We aimed to find a new marker for evaluating disease activity in patients with CD and low CRP.

METHODS

Nine markers, including CRP, platelet count, white blood cell count, fibrin and fibrinogen degradation product, fibrinogen, thrombin-antithrombin complex, <em>prothrombin</em> <em>fragments</em> <em>1</em> + <em>2</em>, PF-4, and β-TG were evaluated in 47 patients with CD and low CRP ((<em>1</em>.0 mg/dl). Patients were assigned to high or low disease activity groups, CDAI-H (CDAI ≥ <em>1</em>50) and CDAI-L (CDAI < <em>1</em>50), respectively.

RESULTS

CDAI-H exhibited significantly higher PF-4 and β-TG levels than CDAI-L (P < 0.0<em>1</em>). Other markers were not significantly different between groups. CDAI was positively correlated with the levels of PF-4 and β-TG (P = 0.0033 and 0.00<em>2</em>4; r = 0.4<em>2</em>0<em>2</em> and 0.43<em>2</em><em>1</em>, respectively). Receiver operating characteristic curve analyses of PF-4 and β-TG showed high sensitivity (6<em>1</em>.9 and 8<em>1</em>%, respectively) and specificity (84.7 and 69.<em>2</em>%, respectively) for diagnosing active CD.

CONCLUSIONS

Among eight potential markers, PF-4 and β-TG were the most highly correlated with CDAI in patients with CD and low CRP. PF-4 and β-TG levels showed promise as new markers for assessing CD in patients with low CRP.

Changes in coagulation may have a profound impact on outcomes following severe burns and the coagulation abnormalities after thermal injury are incompletely described. We postulated that thermal injury induces a systemic hypercoagulable state. With Institutional Review Board approval, five patients were consented for enrollment in this case series. After obtaining informed consent, blood was drawn on hospital days <em>1</em>, <em>2</em>, 3, 5, and 7 or until discharge if discharge was in less than 7 days. Standard coagulation testing was performed, as well as a battery of sophisticated specialized coagulation assays. Other data collected includes fluid resuscitation volumes, pharmacologic interventions, and general physiologic information. Results (n = 5) demonstrate that burns less than 6% total body surface area appear to have little effect on coagulation. Burns greater than 6% appear to induce a systemic hypercoagulable state with a phase and magnitude relationship proportional to total body surface area burned. Severe burns greater than 40% appear to induce a consumptive coagulopathy. <em>Prothrombin</em> <em>fragment</em> <em>1</em>.<em>2</em> may represent a useful screening test for a burn-induced hypercoagulable state.