To reduce the thrombogenic properties of coronary artery stents, a biodegradable polylactic acid (PLA) stent coating with an incorporated thrombin inhibitor and a platelet aggregation inhibitor has been developed. In an ex vivo human stasis model, its effect on platelets, plasmatic coagulation and its release characteristics were studied using whole blood. Bare steel and bare gold-surface stents were compared to steel and gold-surface stents coated with PLA (30 kDa) containing 5% polyethyleneglycol (PEG)-hirudin and <em>1</em>% iloprost, with an empty tube as control. Markers of activated coagulation (<em>prothrombin</em> <em>fragment</em> F<em>1</em>-<em>2</em> and thrombin-antithrombin III complex, TAT), were assayed and the release of drugs from the coating was assessed by aPTT and collagen-induced platelet aggregation. Bare steel and gold stents were completely covered by a blood clot, and high levels of coagulation markers (F<em>1</em>-<em>2</em> <em>fragment</em> and TAT) were detected. No differences in the thrombogenic properties were found between bare gold or steel stents. Coated stents were free of blood clots and only minor elevations of markers were detected. Release data from in-vitro studies over 90 days showed a gradual release of the drugs with an initial exponential release characteristic for PEG-hirudin, slow release of iloprost and a <em>1</em>0% degradation of the PLA carrier. This drug releasing biodegradable coating effectively reduced thrombus formation independent of the metallic surface.

OBJECTIVE

Cardiopulmonary bypass (CPB) systems without a venous reservoir rarely are adopted clinically. The effects of a biocompatible CPB system with a venous reservoir were evaluated on the activation of the coagulation and inflammatory systems.

METHODS

A prospective, randomized controlled trial.

METHODS

A university hospital (single center).

METHODS

Eighty-three coronary artery bypass graft (CABG) surgery patients were assigned to the Physio group (closed venous reservoir, phosphorylcholine coating, and no cardiotomy suction) or the Standard group (open, noncoated, and cardiotomy suction used).

METHODS

Blood samples were obtained at 6 different time points before, during, and after surgery. Nuclear factor-kB (NF-κB) was evaluated before surgery and <em>2</em> and <em>2</em>4 hours after surgery. Myocardial damage was evaluated measuring cardiac troponin I.

RESULTS

Interleukin (IL)-6 (a marker of inflammation), <em>prothrombin</em> <em>fragment</em> <em>1</em>-<em>2</em> (PF-<em>1</em>.<em>2</em>, a marker of thrombin generation), plasmin-antiplasmin complex (PAP, a marker of fibrinolysis), and platelet factor 4 (PF4, a marker of platelet activation) were measured. The DNA binding activity of proinflammatory transcription factor NF-κB was quantified in the isolated lymphomonocyte cells. Surgery caused changes of all plasma biomarkers. This reaction was attenuated strongly in the Physio group; PF-<em>1</em>.<em>2</em>, PAP, and PF4 all were decreased significantly. In the Physio group, a significantly lower cardiac troponin I release was observed postoperatively. After surgery, NF-κB activity was reduced in the Physio group although this difference was not statistically significant.

CONCLUSIONS

A multimodal strategy using a closed and phosphorylcholine-coated CPB circuit together with the avoidance of cardiotomy suction reduced activation of the coagulation and fibrinolytic systems intraoperatively, although these changes did not persist postoperatively. However, no difference in clinical outcome was appreciated on a larger scale.

OBJECTIVE

To assess the predictive value of variables possibly associated with blood loss after coronary artery bypass grafting (CABG).

METHODS

A prospective study.

METHODS

A university hospital.

METHODS

Eighty-nine patients scheduled for elective CABG.

METHODS

Blood samples were drawn before and after surgery. Chest tube drainage was measured hourly until removal of drains.

RESULTS

Activation of coagulation and fibrinolysis, routine clotting tests, and expression of platelet surface antigens were analyzed using flow cytometry. A significant correlation was found among blood loss and activated partial thromboplastin time, fibrinogen, <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em>, D-dimers, platelet count, GPIb and P-selectin expression on platelets, use of internal thoracic artery, cross-clamp time, and thrombin-antithrombin III complex. In a multiple regression model, glycoprotein (GP) Ib expression on platelets, platelet count, use of internal thoracic artery, and D-dimers were significantly associated with blood loss. Logistic regression analysis showed that GPIb and D-dimers predicted an increased blood loss with a positive predictive value of 73% and a negative predictive value of 9<em>1</em>%.

CONCLUSIONS

Postoperative D-dimers and GPIb expression may be useful to exclude nonsurgical causes in bleeding patients after CABG.

Lipid-lowering therapy reduces cardiac events to an extent that is disproportionate to the small degree of regression of coronary atherosclerosis observed among hyperlipidemic patients. We prospectively investigated the effects of lipid reduction using simvastatin on the endothelial dysfunction and hypercoagulability found in hyperlipidemic patients. We measured levels of coagulation factors [factor VII (FVII) coagulant activity (FVIIc), FVII antigen (FVIIAg), activated FVII (FVIIa), and fibrinogen], and markers of coagulation activation [<em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>)] and endothelial cell dysfunction [von Willebrand factor (vWF)] in <em>2</em>0 hyperlipidemic patients, <em>2</em>0 hypertensive patients, and <em>2</em>0 normotensive normolipidemic controls. The levels of FVIIa, FVIIc, FVIIAg, F<em>1</em> + <em>2</em>, and vWF were all higher in hyperlipidemic patients, but only FVIIa, F<em>1</em> + <em>2</em>, and vWF levels were higher in hypertensive patients than in controls. We measured the above parameters in <em>1</em>3 hyperlipidemic patients before and after <em>1</em>, 3, 6, <em>1</em><em>2</em> and <em>2</em>4 months of simvastatin therapy and compared these values with those in <em>1</em>5 hypertensive patients at baseline and after <em>1</em><em>2</em> and <em>2</em>4 months. The median (<em>2</em>5th-75th percentile) level of total cholesterol was decreased from <em>2</em>59 (<em>2</em>55-<em>2</em>78) to <em>2</em>06 (<em>1</em>76-<em>2</em><em>2</em>0) mg/dl after <em>1</em> month of simvastatin therapy and this reduction persisted for <em>2</em> years. The plasma level of vWF [<em>1</em>36% (<em>1</em><em>1</em>3-<em>1</em>58%)] was not changed after <em>1</em> month of administration of simvastatin [<em>1</em>3<em>2</em>% (<em>1</em><em>1</em>5-<em>1</em>53%)], but was decreased after 3 months of treatment [<em>1</em><em>1</em>4% (96-<em>1</em><em>2</em>8%), P<0.0<em>1</em>]. This decrease also persisted for <em>2</em> years during simvastatin therapy and both of these reductions were significant, compared with levels in hypertensive patients. In contrast, levels of fibrinogen, FVIIc, FVIIAg, FVIIa, and F<em>1</em> + <em>2</em> did not change throughout the <em>2</em> years of simvastatin therapy. We conclude that lipid reduction using simvastatin corrects endothelial cell dysfunction but not hypercoagulability in hyperlipidemic patients. The improvement in endothelial cell function brought about by lipid-lowering therapy might contribute to the reduction in cardiac events within a relatively short time period in hyperlipidemic patients.

BACKGROUND

Abdominal aortic aneurysm (AAA) is a chronic inflammatory condition associated with a prothrombotic, hypofibrinolytic diathesis that may increase the risk of cardiovascular events. The effect of endovascular aneurysm repair (EVAR) on this prothrombotic diathesis is not fully understood, especially over the medium and long term. A better understanding of these postintervention changes may improve the risk of cardiovascular complications in the long term. The purpose of this study was to examine thrombin generation, fibrinolysis, platelet and endothelial activation, and the inflammatory response during the <em>1</em><em>2</em> months following EVAR.

METHODS

Twenty-nine patients (mean age, 76.9 years) undergoing EVAR for AAA (mean diameter 6.9 cm) had <em>prothrombin</em> <em>fragment</em> (PF) <em>1</em> + <em>2</em>, thrombin-antithrombin complex (TAT), plasminogen activator inhibitor (PAI) activity, tissue plasminogen activator (t-PA) activity and antigen, soluble P- and E-selectin, and highly sensitive C-reactive protein (hsCRP) measured before and at <em>2</em>4 hours, and <em>1</em>, 6, and <em>1</em><em>2</em> months after surgery.

RESULTS

PF<em>1</em> + <em>2</em> were markedly elevated prior to EVAR and remained so at <em>2</em>4 hours and <em>1</em> month, but had decreased significantly at 6 and <em>1</em><em>2</em> months. TAT was also elevated prior to EVAR and increased still further by <em>2</em>4 hours, but fell to below baseline levels thereafter. PAI activity and t-PA antigen were normal prior to EVAR, increased significantly at <em>2</em>4 hours, and then fell to baseline levels. t-PA activity was only detectable at <em>1</em> and 6 months; there was a significant rise in soluble P- and E-selectin after EVAR, which was sustained for <em>1</em><em>2</em> months. hsCRP increased transiently in response to EVAR but returned to preoperative levels by <em>1</em> month.

CONCLUSIONS

The prothrombotic, hypofibrinolytic diathesis associated with AAA is normalized <em>1</em><em>2</em> months after EVAR. This beneficial systemic effect of EVAR for AAA disease may help protect patients against future thromboembolic cardiovascular events.

There are limited data on the influence of genetic polymorphisms in atrial fibrillation (AF) stroke risk. We hypothesized that a functional haemostatic polymorphism, that is, the factor VII -3<em>2</em>3 Del/Ins polymorphism, would influence the prothrombotic state associated with AF, as well as stroke risk. Other functional polymorphisms were also tested.

METHODS

We performed a cross-sectional study of <em>1</em><em>1</em>9 AF patients, who were compared to 96 patients with stroke secondary to AF. In the first patient group, we analysed plasma <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> levels (F<em>1</em>+<em>2</em>, an index of thrombin generation) to reflect the prothrombotic state of AF.

RESULTS

AF patients carrying the -3<em>2</em>3 Ins allele had lower plasma F<em>1</em>+<em>2</em> levels (P=0.0<em>1</em>5). After multivariate analysis adjusted by age, sex and clinical risk factors, advanced age and 807C/T polymorphism of glycoprotein Ia (GPIa) gene were associated with higher risk of ischaemic stroke (OR: <em>1</em>.06; P=0.003 and OR: <em>1</em>.9<em>1</em>; P=0.0<em>2</em>5), whilst FVII Ins -3<em>2</em>3 allele was associated with lower stroke risk (OR: 0.4<em>1</em>; P=0.0<em>1</em>7).

CONCLUSIONS

FVII -3<em>2</em>3 Ins allele may modulate the prothrombotic state associated with AF. Despite the small sample size, we found that FVII Ins -3<em>2</em>3 allele could be associated with a lower stroke risk in AF, whereas the 807C/T polymorphism may increase the risk.

There is growing evidence for a role of factor XIII (FXIII) in vascular disease. FXIII measures were determined in (i) a nested case-control study from the Second Northwick Park Heart Study of 63 men with myocardial infarction (MI) and <em>1</em><em>2</em>4 age-matched controls and (ii) in a case-control study of 475 subjects with acute stroke and 46<em>1</em> controls followed up for 54 months for mortality. In both studies, measures of FXIII A- and B-subunit antigen, FXIII activity and <em>prothrombin</em> <em>fragments</em> (F<em>1</em> + <em>2</em>) were made. An in vitro model was used to investigate the effects of thrombin activity on FXIII A- and B-subunit antigen levels. In study <em>1</em>, patients clinically free of coronary artery disease who later developed MI had lower adjusted FXIII A-subunit levels at recruitment (<em>1</em><em>2</em>9.<em>2</em>%vs <em>1</em><em>1</em>3.3%, P = 0.007). In study <em>2</em>, stroke patients with large vessel disease had lower A-subunit antigen levels (<em>1</em>0<em>2</em>.<em>1</em>%vs <em>1</em><em>2</em>7.<em>2</em>%, P < 0.00<em>1</em>), but higher F<em>1</em> + <em>2</em> levels (0.94<em>1</em>%vs 0.753%, P < 0.05), than subjects with small vessel disease. Levels of FXIII A-subunit (<em>1</em>00%vs <em>1</em><em>1</em>7%, P < 0.000<em>1</em>) were lower and F<em>1</em> + <em>2</em> higher (<em>1</em>.0<em>2</em>0%vs 0.70<em>2</em>%, P < 0.000<em>1</em>) in stroke patients who had died compared with those still alive at the end of the follow-up period. Low concentrations of FXIII A-subunit antigen predicted vascular outcome in otherwise healthy subjects and relate to both size of infarct and poor post-stroke survival in patients with acute ischaemic stroke. Low in vitro concentrations of FXIII A-subunit antigen wererelated to increased thrombin generation and, thus, increased risk of thrombotic events.

Thirty-eight obese children and adolescents were investigated for a possible relation between cholesterol and markers of platelet activation, endothelial cell dysfunction, and activation of the coagulation system. Soluble P-selectin, von Willebrand factor antigen (vWf-Ag), D-dimer, and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>) were determined by enzyme-linked immunosorbent assays, and factor VIII coagulant activity (VIIIc) was measured by means of one-stage clotting assay. Cholesterol correlated significantly with log P-selectin (r = 0.43, P = 0.003) and log D-dimer (r = 0.33, P = 0.0<em>2</em>). Cholesterol did not correlate with vWf-Ag, factor VIIIc, and F<em>1</em> + <em>2</em>. Log P-selectin correlated significantly with log D-dimer (r = 0.4<em>2</em>, P = 0.003), which remained significant after adjustment for cholesterol (P = 0.0<em>2</em>). Log D-dimer correlated significantly with F<em>1</em> + <em>2</em> (r = 0.38, P = 0.0<em>1</em>). Our study demonstrates that, in obese children and adolescents, cholesterol is significantly associated with P-selectin and D-dimer, and suggests an unfavorable intercorrelation between metabolic and hemostatic risk factors for coronary heart disease in childhood obesity.

BACKGROUND

Although a major role of coronary thrombosis in the pathogenesis of unstable angina has been demonstrated, the results of a series of studies have suggested that activation of the hemostatic system may not be confined to ischemic episodes. The purpose of this study was to investigate the temporal relation between ischemic episodes and activation of the coagulation system in unstable angina.

RESULTS

Thrombin-antithrombin III (TAT) and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>) levels were measured in <em>1</em>3 patients during spontaneous ischemic episodes (time 0, 5, and <em>1</em>5 minutes and <em>1</em> hour) to evaluate the time course of the activation of the coagulation system associated with the development of ischemia (protocol A). TAT and F<em>1</em> + <em>2</em> levels were also measured in <em>2</em>8 patients with unstable angina on admission to hospital (every 6 hours for <em>2</em>4 hours and daily for 3 days) to assess their temporal relation with ischemic episodes (protocol B). In protocol A, TAT and F<em>1</em> + <em>2</em> levels were elevated in <em>1</em>0 of <em>1</em>3 patients (77%) in at least <em>1</em> sample. The median value of TAT showed a peak at 5 minutes and returned to baseline within <em>1</em>5 minutes (P < .05), consistent with its plasma half-life of 5 minutes, whereas the median value of F<em>1</em> + <em>2</em> showed no significant changes, possibly because of its longer half-life, which tends to dampen sudden bursts of thrombin production. In protocol B, activation of the clotting system was found in <em>1</em>0 of 33 samples (30%) temporally related to ischemia and also in <em>2</em>3 of <em>1</em>50 (<em>1</em>5%, P = .07) of those not temporally related to ischemia.

CONCLUSIONS

Our study demonstrates that patients with active unstable angina develop frequent bursts of thrombin production not necessarily associated with ischemic episodes and that, conversely, some ischemic episodes are not associated with evidence of thrombin activation.

<AbstractText>D-dimer (DD) is the most used fibrin-related marker and has been proposed, either alone or in combination with other variables, as prognostic factor in patients with sepsis. However, DD generation depends on both coagulation and fibrinolysis, meaning that it may give false negative results in conditions associated with marked fibrinolytic inhibition such as sepsis. In this study, we tested whether correction of DD for thrombin and plasmin generation could improve its prognostic significance in septic patients.</AbstractText><p><div><b>MATERIAL AND METHODS</b></div>We performed a nested study in <em>2</em>69 septic patients from the ALBIOS trial. DD, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>) and plasmin-antiplasmin complex (PAP) were assayed at day <em>1</em>. Corrected DD (DD_corr) was calculated by the formula DD×PAP/F<em>1</em>+<em>2</em>, such that the lower the DD_corr the greater the imbalance in favour of fibrin formation over fibrin lysis, and vice-versa. Primary outcome was 90-day mortality.</p><p><div><b>RESULTS</b></div>DD_corr showed a J-shaped relationship with mortality, which was highest in the first DD_corr tertile (low fibrinolysis), intermediate in the 3^rd (high fibrinolysis), and lowest in the <em>2</em>^nd (balanced fibrinolysis), suggesting an increased risk whenever the coagulation-fibrinolysis balance is tilted (p<0.000<em>1</em>). Neither DD, nor PAP or F<em>1</em>+<em>2</em> showed a comparable association with mortality. DD_corr was an independent prognostic factor in multivariable Cox models and significantly improved risk stratification (cNRI≥0.<em>2</em>8). Finally, by combining DD_corr and SOFA tertiles, we developed a score with high discriminatory power.</p><p><div><b>DISCUSSION</b></div>DD_corr is a good marker of the in vivo coagulation-fibrinolysis balance and displays a prognostic value in sepsis much higher than DD.</p>

We have looked for evidence of coagulation activation in six subjects with haemophilia B by performing a single-blind active control cross-over study comparing a recently developed factor IX concentrate with a conventional <em>prothrombin</em> complex concentrate (PCC). Samples were obtained before infusion and at 0.<em>2</em>5, 0.5, <em>1</em>, <em>2</em>, 4, 6, <em>1</em><em>2</em>, <em>2</em>4, 36 and 48 h for assay of factor IX, <em>prothrombin</em> time, fibrinopeptide A (FPA), <em>prothrombin</em> <em>fragment</em> F<em>1</em> + <em>2</em>, D-dimer, thrombin-antithrombin complexes (TAT) and antithrombin III (ATIII). Following administration of the PCC there was evidence of coagulation activation in five of the six recipients for up to 6 h after the infusion. The factor IX concentrate induced a moderate degree of coagulation activation in one subject. There was no significant difference between the two products in respect of either recovery or half-life. This study provides further evidence that the new high purity preparations of factor IX concentrates produce significantly less coagulation activation than currently available PCCs. It remains to be established whether this will result in a corresponding reduction in thromboembolic complications in clinical use.

The purpose of this study was to investigate the safety and efficacy of a novel vascular sealing device that incorporates a unique low-profile balloon-positioning catheter and a procoagulant delivered after diagnostic cardiac catheterization and percutaneous transluminal coronary angioplasty (PTCA) procedures. Current management of the vascular access site after percutaneous interventions is associated with patient discomfort and complications. Based on previously reported successful results in canine models, we proceeded with this first human feasibility and safety study. Immediately after an invasive procedure, the sealing device was successfully deployed at the femoral arterial access site in <em>2</em>4 of <em>2</em>4 procedures (diagnostic <em>1</em>9, PTCA 5). All patients were followed up at <em>1</em> month with clinical assessment, ankle-brachial index measurement, and Doppler ultrasound. Successful hemostasis was achieved in all patients. The activated clotting time before sealing device deployment was <em>1</em><em>2</em>5.5 +/- <em>2</em><em>2</em>.<em>2</em> and <em>2</em>67.8 +/- 60.0 seconds for diagnostic and PTCA patients, respectively. The time to hemostasis was <em>2</em>.5 +/- 0.9 minutes for diagnostic and 6.0 +/- <em>2</em>.<em>2</em> minutes for PTCA patients. No major complications were observed. Coagulation markers (fibrinogen, D-dimer, thrombin-antithrombin-3 complex, and <em>prothrombin</em> <em>fragment</em> <em>1</em> and <em>2</em>) measured before and after sealing device deployment did not reveal excessive intravascular thrombin generation or other coagulopathy. This novel vascular sealing device successfully achieves safe and effective vascular access site hemostasis immediately after cardiac catheterization and PTCA. These promising first human results will need to be confirmed by a multicenter randomized trial.

BACKGROUND

We hypothesized that off-pump coronary artery bypass grafting has less impact on the hemostatic systems than on-pump surgery.

METHODS

Thirty-one patients were randomized to on-pump or off-pump coronary artery bypass grafting. Factors of hemostasis as well as markers of endothelial activation were measured up to <em>2</em>4 hours after the operation: Fibrin D dimer, <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, alpha<em>2</em>-macroglobulin, protein C<em>1</em> esterase inhibitor, fibronectin, and von Willebrand factor. Overall hemostasis potential, overall coagulation potential, and overall fibrinolysis potential were determined with a previously developed assay. We also measured platelet count before and after surgery.

RESULTS

Fibrin D dimer and <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> concentrations were lower during surgery in the off-pump group (p < 0.00<em>1</em>). Four hours after admission to the intensive care unit, these differences were eliminated. alpha<em>2</em>-macroglobulin, protein C<em>1</em> esterase inhibitor, fibronectin, and von Willebrand factor concentrations did not differ between groups (p = 0.59, p = 0.<em>2</em>8, p = 0.<em>2</em><em>2</em>, and p = 0.69). Protein C<em>1</em> esterase inhibitor and von Willebrand factor concentrations increased over time (p < 0.00<em>1</em>) in both groups. Overall hemostasis potential and overall coagulation potential increased over time (p < 0.00<em>1</em>), while overall fibrinolysis potential decreased (p < 0.00<em>1</em>) with no difference between groups (p = 0.69, p = 0.9<em>1</em>). Platelet count decreased on the first postoperative day (p < 0.00<em>1</em>), but increased from the first to the third postoperative day (p = 0.004) in both groups without any inter group difference (p = 0.8<em>2</em>).

CONCLUSIONS

There was a tendency toward less activation of coagulation and fibrinolysis in low-risk patients during elective off-pump coronary artery bypass surgery when compared with on-pump surgery.

Coagulation and fibrinolytic studies have been performed in patients who were undergoing major gynaecological surgery and randomised to either fixed minidose warfarin (<em>1</em> mg daily) or matched placebo. With warfarin, a prolongation of the <em>prothrombin</em> time was observed on day <em>2</em> which persisted for at least 5 days and was greater than with placebo. The maximal postoperative mean INR was, however, only <em>1</em>.<em>2</em> which is considerably less than the target value for prophylaxis of deep vein thrombosis with full dose warfarin. The warfarin group showed two unexpected findings: significantly elevated fibrin specific degradation products throughout the postoperative period compared with placebo and absence of the expected rise of PAI, the major fibrinolytic inhibitor, on the first day after surgery. Levels of fibrinogen degradation products and F<em>1</em> + <em>2</em> <em>prothrombin</em> <em>fragments</em> rose significantly and progressively in both groups in the postoperative period. With placebo, F<em>1</em> + <em>2</em> showed an apparent higher percentage increase on each post-operative day but the differences between the groups were not significant. Increased fibrinolysis may be one of the mechanisms for the protective action of minidose warfarin in prophylaxis of DVT after major surgery.

Anticoagulant response to activated protein C (APC) was studied in 40 healthy subjects and 67 patients with insulin-dependent diabetes mellitus (IDDM) using a modified activated thromboplastin time assay. Results are expressed in terms of the APC sensitivity ratio (APC SR). In addition, plasma levels of protein C, total and free protein S (PS), coagulation factors V and VIII, and <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>) were measured. Patients with IDDM and a urinary albumin excretion rate (UAER) < 30 mg/<em>2</em>4 h showed a median APC SR of <em>2</em>.5 (interquartile range <em>2</em>.3-<em>2</em>.9). In patients with a UAER between 30 and 300 mg/<em>2</em>4 h, the median APC SR was <em>2</em>.7 (<em>2</em>.7-<em>2</em>.9). Both values were significantly greater than the median APC SR of <em>2</em>.<em>1</em> (<em>2</em>.0-<em>2</em>.5) observed in healthy control subjects (P < 0.00<em>1</em>). Also, the percentage of subjects with an APC SR < or = <em>2</em>.0 was markedly smaller in both patient groups. Factor V and VIII levels were not significantly different between IDDM patients and healthy subjects. Grouping of IDDM patients according to the APC SR revealed significantly enhanced levels of total PS (P < 0.05) and factor VIII (P < 0.0<em>1</em>) in patients with a poor anticoagulant response to APC (APC SR < or = <em>2</em>.0) compared with those with an APC SR>> <em>2</em>.7. The negative correlation of the APC SR in diabetic patients with both coagulation and anticoagulation factors indicates a complex role of this parameter in regulating the coagulation system in IDDM.

Acetylsalicylic acid (ASA) prevents thromboembolic events by inhibiting platelet function through blocking of cyclooxygenase type <em>1</em> (COX-<em>1</em>). A nitroderivate of ASA, <em>2</em>-(acetyloxy)benzoic acid 3-(nitrooxymethyl)-phenyl ester (NCX 40<em>1</em>6) was synthesized, which additionally acts through nitric oxide release. In various in vitro and animal studies NCX 40<em>1</em>6 exhibited antithrombotic and anti-platelet properties. We used the standardized model of endotoxin infusion into human volunteers to compare the effects of NCX 40<em>1</em>6 and ASA on platelet function and TF-induced coagulation activation. The trial consisted of two parts. In the first part, <em>1</em>0 healthy male volunteers were included in a randomized, open cross-over trial to find a NCX formulation with optimal tolerability and pharmacokinetic data were obtained. The second part was a randomized, double blind placebo controlled clinical trial consisting of 30 healthy male volunteers in three parallel groups (n = <em>1</em>0 per group). Volunteers received either NCX 40<em>1</em>6 (800 mg b.i.d.), ASA (4<em>2</em>5 mg b.i.d.) or placebo for 7 days, before infusion of <em>2</em> ng/kg endotoxin on day 8. ASA attenuated the endotoxin-induced platelet plug formation (measured by PFA-<em>1</em>00) significantly better than NCX 40<em>1</em>6 and placebo (p < 0.004), while there was no difference in soluble P-selectin or VWF-levels. Urine <em>1</em><em>1</em>-dehydro-thromboxane B(<em>2</em>) levels were significantly lower in the ASA and NCX 40<em>1</em>6 groups as compared to placebo (p < 0.05). Neither ASA nor NCX 40<em>1</em>6 significantly changed <em>prothrombin</em> <em>fragment</em>(<em>1</em> + <em>2</em>), D-Dimer or tissue factor (TF)-mRNA levels. In summary, NCX 40<em>1</em>6 had no effect on VWF release, platelet activation as measured by soluble P-selectin or TF gene expression. NCX 40<em>1</em>6, at the dose tested, unlike ASA, had no effect on platelet collagen/epinephrine induced plug formation under high shear rates.

BACKGROUND

No data are available about the optimal duration of oral anticoagulant therapy (OAT) after an episode of venous thromboembolism (VTE) occurring in renal transplant (RT) recipients. Our study was undertaken to evaluate the risk of VTE recurrence in patients developing a first episode of VTE after RT.

METHODS

Among 484 RT patients, 34 (7%) developed a first VTE: <em>2</em>8/34 VTE patients (Group <em>1</em>) were prospectively studied, after stopping OAT. Group <em>1</em> was compared with a group of 84 patients without history of renal disease who had suffered from a first episode of VTE matched for age, sex and type of thrombotic event (Group <em>2</em>) and with a matched group of 84 RT recipients with no history of VTE (Group 3). After OAT withdrawal, blood samples were obtained for thrombophilia and clotting activation markers (<em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>) and D-dimer plasma levels).

RESULTS

During follow-up, <em>1</em>4/<em>2</em>8 patients of Group <em>1</em> and 8/84 patients of Group <em>2</em> experienced VTE recurrence (P < 0.0005). Homocysteine, F<em>1</em>+<em>2</em> and D-dimer plasma levels were significantly higher in Group <em>1</em> than in Group <em>2</em> and 3 (P < 0.000<em>1</em> and <0.05 respectively) for all the three parameters.

CONCLUSIONS

Our data outline the high risk of VTE recurrence in RT recipients. Strategies for VTE recurrence prevention are needed; Prolonged OAT, in spite of the high bleeding risk of RT patients, should be considered in this respect.

BACKGROUND

Rivaroxaban is an oral anticoagulant that effectively prevents thromboembolic complications using fixed doses without requiring laboratory monitoring. In this study, we aimed to examine the coagulation status in patients with non-valvular atrial fibrillation (NVAF) treated with rivaroxaban compared with warfarin.

RESULTS

The study group consisted of 85 consecutive Japanese patients with NVAF who received rivaroxaban (n=33) or warfarin (n=5<em>2</em>) from June <em>2</em>0<em>1</em>3 to February <em>2</em>0<em>1</em>4. We compared the coagulation status between the rivaroxaban and warfarin treatments. The <em>prothrombin</em> time (PT) values did not significantly differ between the two groups. However, the <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em> (F<em>1</em>+<em>2</em>) level, a marker of thrombin generation, was significantly higher in the rivaroxaban group than the warfarin group (<em>2</em>0<em>2</em>±88pmol/l vs. <em>1</em><em>1</em>4±79pmol/l, p<0.00<em>1</em>). Next, we collected blood samples from <em>1</em>8 patients taking rivaroxaban at 3h and <em>1</em>5h after the drug intake and evaluated the time-dependent changes in the coagulation status. The PT values at 3h after the drug intake were significantly more prolonged than those at <em>1</em>5h (p<0.00<em>1</em>). However, there were no significant differences in the F<em>1</em>+<em>2</em> levels between the two time points (<em>1</em>94±73pmol/l [at 3h] vs. <em>1</em>65±6<em>1</em>pmol/l [at <em>1</em>5h], p=0.<em>1</em><em>1</em><em>2</em>).

CONCLUSIONS

Our preliminary results suggest that the thrombin generation level is stable regardless of the time elapsed after rivaroxaban intake, and warfarin treatment may inhibit thrombin generation more aggressively than rivaroxaban.

The efficacy of conventional dose adjusted oral anticoagulation for stroke prevention in patients with non-valvular atrial fibrillation is well-documented but not considered ideal as primary antithrombotic treatment in elderly patients. The antithrombotic effect of fixed minidose warfarin <em>1</em>.<em>2</em>5 mg/day alone or in combination with aspirin 300 mg/day, of conventional dose adjusted warfarin (INR <em>2</em>.0-3.0), and of aspirin 300 mg/day have been investigated in outpatients with chronic nonvalvular atrial fibrillation in the second Copenhagen Atrial Fibrillation, Aspirin and Anticoagulant Therapy Study (AFASAK <em>2</em>). In order to investigate the effect on the coagulation system of the treatments, the International Normalized Ratio of the <em>prothrombin</em> time (INR) and <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F<em>1</em> + <em>2</em>) were monitored at baseline and after three months of treatment in <em>1</em>00 patients consecutively included in the trial. At baseline no differences in INR and F<em>1</em> + <em>2</em> between the four treatment groups were present. After three months of therapy the level of INR increased significantly from baseline in patients receiving warfarin in any dose and the level of F<em>1</em> + <em>2</em> decreased significantly by combined minidose warfarin-aspirin and by dose adjusted warfarin. When comparing the changes over time in F<em>1</em> + <em>2</em> (three-month value minus baseline value) during therapy with fixed minidose warfarin, combined minidose warfarin-aspirin and aspirin alone no significant difference between the groups was found. In conclusion, INR was changed by all three warfarin regimens but only dose adjusted warfarin (INR <em>2</em>.0-3.0) had a marked effect on F<em>1</em> + <em>2</em>.

The painful crisis accounts for the majority of sickle cell disease (SCD) related hospital admissions. The prototypic long pentraxin 3 (PTX3), an acute phase protein, is elevated in patients with inflammatory and ischemic states. As the sickle cell painful crisis is associated with both inflammation and tissue ischemia, we questioned whether plasma PTX3 levels are increased during and associated with painful crisis severity. Furthermore, since PTX3 up-regulates endothelial expression of tissue factor we studied PTX levels in relation to markers of endothelial and coagulation activation. Plasma levels of PTX3, ultra-sensitive C-reactive protein (US-CRP), <em>prothrombin</em> <em>fragment</em> <em>1</em>+<em>2</em>, thrombin-antithrombin (TAT) complexes, von Willebrand Factor antigen and soluble vascular adhesion molecule-<em>1</em> were determined in <em>1</em>05 asymptomatic sickle cell patients, 33 patients during painful crisis and 30 race matched healthy controls. Plasma PTX3 levels were comparable between patients in asymptomatic state and healthy controls, but significantly higher during painful crisis (P<0.0<em>1</em>). US-CRP levels were higher in asymptomatic patients compared to controls (P<0.000<em>1</em>) and increased further during painful crisis (P<0.000<em>1</em>). PTX3 levels at presentation with painful crisis correlated significantly with the duration of subsequent hospital admission (r(s) = 0.43; P = 0.0<em>1</em>3), whereas US-CRP levels did not. PTX3 levels did not correlate with markers of hypercoagulability. The increase of PTX3 levels during painful crisis and their relation to the duration of subsequent hospital stay suggest that PTX3 might serve both as a diagnostic and severity marker of the painful sickle cell crisis.

Lower extremity ischemia is one aspect of atherosclerosis, a disease associated with both inflammation and hypercoagulability. Many recent studies have focused on a diversity of mechanisms by which inflammation can promote blood clotting. However, it has not been proven that inflammation can actually trigger clinically relevant thrombus formation in vivo. The purpose of the study was to determine the plasma levels of markers of inflammation and their possible association with markers for coagulability with special emphasis on the difference between patients with and without diabetes. Forty-six patients, <em>2</em>0 diabetics and <em>2</em>6 without diabetes scheduled for lower extremity revascularisation were examined by preoperative blood sampling. A strong positive correlation between C-reactive protein (CRP) and fibrinogen was found, particularly in diabetics. A high fibrinogen level was not associated with other markers of hypercoagulability, Thrombin-Antithrombin (TAT), <em>Prothrombin</em> <em>Fragment</em> <em>1</em>+<em>2</em> (F <em>1</em>+<em>2</em>) and D-dimer although the latter three correlated with each other. There was also a correlation between von Willebrand antigen (vWF) and CRP, also in this case the relationship was dependent on the findings in patients with diabetes. It is concluded that there is a difference between diabetic and nondiabetic patients with lower limb ischemia with the former showing stronger signs of inflammation.

Plasma levels of <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> (F <em>1</em> + <em>2</em>), of thrombin-antithrombin III complexes (TAT) and of D-dimers were evaluated at several time intervals in <em>1</em>5 patients affected by acute proximal deep vein thrombosis, complicated or not by pulmonary embolism, and treated by conventional heparin therapy for 9 d. The mean levels of the three markers remained significantly increased throughout the period of observation, except for F <em>1</em> + <em>2</em> on day 9, when compared to normal values established in a population of normal healthy blood donors. However, whereas heparin significantly decreased the plasma levels of F <em>1</em> + <em>2</em> and of TAT complexes in less than 3 d. D-dimer levels were not significantly altered. Significant correlations were observed between the plasma levels of the three markers but they were not correlated to the actual intensity of heparin treatment evaluated as the activated partial thromboplastin time prolongation. These results indicate that heparin improves the hypercoagulable state associated with a deep vein thrombosis within the first days of treatment as indicated by TAT and F <em>1</em> + <em>2</em>. They also account for the performances of D-dimer assay for the diagnosis of deep vein thrombosis in patients already receiving heparin, a common situation in routine hospital practice.

Factor (F)Xa and thrombin bound to the clot during its formation contribute to the propensity of thrombi to activate the coagulation system. The aim of this work was to study the inhibition of clot-bound FXa and clot-bound thrombin by SanOrg<em>1</em><em>2</em>378<em>1</em>A, a synthetic hexadecasaccharide that enhances the inhibition of thrombin and FXa by antithrombin (AT). SanOrg<em>1</em><em>2</em>378<em>1</em>A, designed to exhibit low non-specific binding to proteins other than AT, was compared with heparin. In buffer, heparin and SanOrg<em>1</em><em>2</em>378<em>1</em>A inhibited FXa and thrombin at similar concentrations [concentration inhibiting 50% (IC50) of Xa and IIa activity were, respectively: heparin <em>1</em><em>2</em>0 +/- 7 and 3 +/- <em>1</em> ng mL-<em>1</em>; SanOrg<em>1</em><em>2</em>378<em>1</em>A 77 +/- 5 and 4 +/- <em>1</em> ng mL-<em>1</em>]. In human plasma, the activity of both compounds was reduced, although the activity of heparin was much more affected than that of SanOrg<em>1</em><em>2</em>378<em>1</em>A (IC50 values for inhibition of FXa and FIIa activity were, respectively: heparin <em>1</em>00 +/- 5 and 800 +/- 40 ng mL-<em>1</em>; SanOrg<em>1</em><em>2</em>378<em>1</em>A <em>1</em>0 +/- 5 and 30 +/- 3 ng mL-<em>1</em>). We demonstrated, in agreement with our previous results, that the procoagulant activity of the clot is essentially due to clot-bound FXa and to some extent to clot-bound thrombin. We showed that heparin and SanOrg<em>1</em><em>2</em>378<em>1</em>A were able to inhibit <em>fragment</em> F<em>1</em>+<em>2</em> generation induced by clot-bound FXa with IC50 values of <em>2</em> +/- 0.5 micro g mL-<em>1</em> and 0.6 +/- 0.<em>2</em> micro g mL-<em>1</em>, respectively. Both compounds also inhibited clot-bound thrombin activity, the IC50 values of heparin and SanOrg<em>1</em><em>2</em>378<em>1</em>A being <em>1</em> +/- 0.0<em>1</em> micro g mL-<em>1</em> and 0.<em>1</em> +/- 0.<em>1</em> micro g mL-<em>1</em>, respectively. Moreover, both heparin and SanOrg<em>1</em><em>2</em>378<em>1</em>A significantly inhibited fibrinopeptide A generated by the action of clot-bound thrombin on fibrinogen but also by free thrombin generated from <em>prothrombin</em> by clot-bound FXa with IC50 values of 4 +/- 0.6 and <em>1</em> +/- 0.<em>1</em> micro g mL-<em>1</em>, respectively. As with clot-bound enzymatic activities, SanOrg<em>1</em><em>2</em>378<em>1</em>A was three times more active than heparin in vivo on fibrinogen accretion onto a pre-existing thrombus and as activators of recombinant tissue-type plasminogen activator-induced thrombolysis. In conclusion, due to the specific activities of SanOrg<em>1</em><em>2</em>378<em>1</em>A, this compound is much more active than heparin in the presence of plasma proteins, on clot-bound enzymes and in in vivo models of thrombosis/thrombolysis.

In patients with myocardial infarction, thrombolytic therapy induces a paradoxical activation of the hemostatic mechanism. In patients with unstable angina, the effect of thrombolysis on the coagulation cascade is unknown. We prospectively measured the plasma concentrations of <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> and fibrinopeptide A in consecutive patients with unstable angina randomized to receive placebo alone (n = <em>2</em>3), streptokinase <em>1</em>,500,000 IU over <em>1</em> hour followed by a 48-hour placebo infusion (n = <em>2</em><em>1</em>), or streptokinase <em>2</em>50,000 over <em>1</em> hour followed by a continuous infusion of <em>1</em>00,000 IU per hour over 48 hours (n = <em>2</em>0). All the patients received intravenous heparin for 7<em>2</em> hours. The plasma levels of the different markers were measured at baseline, 90 minutes, <em>2</em>4 hours, and 48 hours after the start of therapy. The median baseline plasma concentrations of <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> and fibrinopeptide A were similar in the three treatment groups. In comparison with placebo, an increase in plasma <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> and fibrinopeptide A, was observed after 90 minutes in the two groups receiving thrombolysis. After <em>2</em>4 and 48 hours, the <em>prothrombin</em> <em>fragment</em> <em>1</em> + <em>2</em> levels remained significantly higher only in the patients receiving the 48-hour streptokinase infusion. In patients with unstable angina, thrombolytic therapy induces an activation of the hemostatic mechanism, despite concomitant heparin administration; in those receiving a prolonged streptokinase infusion, the activation of coagulation persists for as long as the drug is administered.