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Heparin-induced thrombocytopenia (HIT) is an immune-mediated adverse drug effect that occurs in 0.1–5% of heparin treated patients. Management of acute HIT currently involves (1) cessation of heparin exposure, and (2) inhibition of coagulation with an anticoagulant other than heparin. Several anticoagulants can be considered for the treatment of HIT. Anticoagulant monitoring, management of drug-induced adverse events including bleeding, and therapeutic dosing schedules in selected clinical settings represent challenges to the clinician treating HIT patients. Moreover, the fact that not all registered anticoagulants are approved for HIT in Switzerland further complicates the management of HIT. The present recommendations on the anticoagulant treatment of HIT in Switzerland have been elaborated by a panel of Swiss experts belonging to the Working Party Hemostasis (WPH) of the Swiss Society of Hematology (SGH-SSH). They are intended to support clinicians in their decision making when treating HIT patients.

The new oral anticoagulants (NOACs) represent alternative antithrombotic agents for prophylaxis and therapy of thromboembolic diseases. They act either by inhibition of the clotting factor Xa or IIa (thrombin). As a consequence, they influence several coagulation assays (for example prothrombin time, activated partial thromboplastin time). Because of the short half-life of these new agents, these changes show great variations in the course of 24 hours. Furthermore, there are significant differences of laboratory results depending on the used reagents. We explain the influence of apixaban, rivaroxaban (factor Xa inhibitors) and dabigatran (thrombin inhibitor) on the most commonly used coagulation assays. Besides we show that this influence depends on the way of action of the drug as well as on the principle of the coagulation assay. Being aware of this relationships helps to interpret the results of coagulation assays under influence of NOACs correctly., (© Georg Thieme Verlag KG Stuttgart · New York.)

New oral anticoagulants promise to overcome essential drawbacks of traditional substances. They have a predictable therapeutic effect, a wide therapeutic window, only limited interaction with food and drugs and can be administered p.o. with a fixed dose. On the other hand, knowledge on the laboratory management of new anticoagulants is limited. In the present article we discuss possible indications and available assays for monitoring of Rivaroxaban, Apixaban and Dabigatran. Furthermore, we discuss interpretation of routine coagulation tests during therapy with these new drugs.

Background: Psychological distress might affect the international normalized ratio (INR), but effects might vary depending on oral anticoagulant (OAC) therapy., Objectives: To investigate the association of psychological distress with INR and clotting factors of the extrinsic pathway in patients with and without OAC therapy., Patients and Methods: We studied 190 patients with a previous venous thromboembolism (VTE); 148 had discontinued OAC therapy and 42 had ongoing OAC therapy. To assess psychological distress, all patients completed validated questionnaires to measure symptoms of depression, anxiety, worrying, anger and hostility. INR, fibrinogen, factor (F)II:C, FV:C, FVII:C and FX:C were measured as part of outpatient thrombophilia work-up., Results: In VTE patients without OAC therapy, the odds of a reduced INR (< 1.00) were significantly increased from 1.5 to 1.8 times for an increase of 1 standard deviation (SD) in symptoms of depression, anxiety, worrying and anger, respectively, after adjusting for gender, age, body mass index, socioeconomic status, hematocrit and C-reactive protein. Worrying, anger and hostility also showed significant direct associations with FVII:C. In patients with OAC therapy, INR was unrelated to a negative affect; however, lower FVII:C related to anxiety and worrying as well as lower FX:C related to anger and hostility were observed in patients with OAC therapy compared with those without OAC therapy., Conclusions: Psychological distress was associated with a reduced INR in VTE patients without OAC therapy. The direction of the association between psychological distress and activity in some clotting factors of the extrinsic coagulation pathway might differ depending on whether VTE patients are under OAC therapy or not., (© 2012 International Society on Thrombosis and Haemostasis.)

Background: Low-molecular-weight heparins (LMWH) are effective, safe and convenient for anticoagulation. Their use is limited in patients with renal insufficiency (RI) because of bioaccumulation., Objectives: Evaluate pharmacokinetic data of dalteparin at a therapeutic dose in patients with RI., Patients and Methods: Prospective observational cohort study. Inpatients were included into three groups according to glomerular filtration rate (GFR): A > or = 60, B 30-59, C < 30 mL min(-1) 1.73 m(-2). Dalteparin was injected subcutaneously (s.c.) twice daily. Peak plasma anti-factor Xa activity (anti-Xa) was measured and adjusted to applied dose and body weight after the first dose, on day 2, and every 2nd day afterwards. Bioaccumulation factor R was calculated as quotient of the last and the first adjusted anti-Xa. Data are shown as median (interquartile range, IQR)., Results: Thirty-two patients (23 men) receiving dalteparin for > or = 2 days were analyzed. Follow-up was 6 days (IQR 4-10, range 2-22). Median dose was 90 (73-106) units kg(-1) per 12 h (P = 0.68). After the first dose, adjusted anti-Xa levels were 3.5 (2.6-5.0), 4.8 (3.3-5.5), 4.5 (3.7-7.5) x 10(-3) for the groups A, B, C; P = 0.26. On the last day, they were 6.1 (3.7-7.3), 7.1 (5.6-8.3), 10.2 (7.8-13.2) x 10(-3); A compared with C, P = 0.002. R was 1.46 (1.15-1.82), 1.36 (1.20-2.16) and 2.28 (1.53-2.93); A compared with C, P = 0.18., Conclusion: Therapeutically dosed dalteparin accumulates in patients with severe RI (group C). Dose adjustments according to anti-Xa are recommended for dalteparin if used in this patient population. However, no simple dosing scheme can be suggested yet because of wide inter-individual variation.

Self management of oral anticoagulation (OAC) has been demonstrated to improve the quality of oral anticoagulation as assessed by the percentage of INR values within the individual target range. There were tendentially less bleeding and thromboembolic complications in the group with self management of OAC. The capillary INR values of the only available monitor in Switzerland (CoaguChek, Roche Diagnostics, AG) correlated good with venous INR. Thus, self management of OAC may be a valuable alternative to conventional anticoagulation in selected and motivated patients on long term anticoagulation.

Deep venous thrombosis and pulmonary embolism are considered to be two variants of one disease--'venous thromboembolism'. Pathogenesis, therapy and prognosis of these both entities are very similar and therefore the term 'venous thromboembolism' has been used in recent literature. The cornerstone of therapy is anticoagulation and initially consists of heparin for at least five days. Because of pharmacokinetic advantages low molecular weight heparins are the therapy of choice. They are as efficient and save as unfractionated heparins and allow weight-adapted dosing with daily subcutaneous injections in most patients. Low molecular weight heparins do not require regularly laboratory monitoring with few exceptions, e.g. renal failure. Therefore outpatient treatment of deep venous thrombosis is possible in most patients. Although there are promising data about outpatient treatment of pulmonary embolism, this is still being studied and can not be recommended outside clinical trials. Introduction of coumarin therapy for venous thromboembolism should be started on day 1 of diagnosis, keeping the total duration of heparin therapy at no more than five days and therefore minimizing the incidence of heparin-induced thrombocytopenia. Evidence from multiple studies indicates that effective coumarin therapy in venous thromboembolism is usually reflected by an INR of 2.0 to 3.0. In patients with massive and hemodynamically relevant thromboembolism alternative therapeutic approaches such as thrombolytic therapy, thrombectomy or insertion of intravenous filters may be useful. Adequately fit compression stockings can reduce the risk of post-thrombotic syndrome after deep venous thrombosis.

We measured anti-Xa activity before and at 2, 4, 9 and 12 h after subcutaneous injection of 0.3 ml nadroparin (2850 IU anti-Xa) in normal-weight volunteers (median bodyweight 71 kg, n=5) and compared them to the anti-Xa activity after subcutaneous injection of 0.6 ml nadroparin (5700 IU anti-Xa) in obese patients (median bodyweight 134 kg, n=8). The resulting median anti-Xa activity after 4 h was 1.4 times greater in the group of obese patients. This finding suggests that a linear, weight-adjusted increase in the prophylactic dose of nadroparin does not result in a linear increase of anti-Xa activity in obese patients.

The recent discovery of five patients with coumarin sensitive FIX-variants due to a missense mutation in the FIX propeptide, either Ala-10Val or Ala-10Thr, has highlighted a novel type of genetic predisposition to bleeding during oral anticoagulant therapy (OAT). In the present study, we report six additional patients with such FIX variants. Haplotype analysis of FIX polymorphisms revealed a founder effect in the five German and Swiss patients with the Val-10 variant. Also, four Thr-10 variants detected in Germany, Switzerland and Great Britain derived from a common founder. Two Thr-10 variants from USA showed an independent de novo origin at a CpG dinucleotide that in general represents a mutation hotspot. These findings implicate the existence of additional subjects with corresponding variants in the populations of various countries. Even though the rare occurrence of these variants does not justify a general aPTT screening during OAT, it is recommended to monitor each bleeding event during OAT in males in order to exclude a genetic predisposition to bleeding by means of the following testing strategy: a) aPTT-testing in each bleeding complication of male patients during OAT, b) if aPTT is disproportionately prolonged, determination of FIX:C, and c) if FIX:C is disproportionately decreased as compared to FII:C, FVII:C and FX:C, sequencing of exon 2 of the FIX gene. This strategy will provide a cost-effective and safe procedure to identify patients that carry the FIX variants. Moreover, such a strategy accumulates data about the prevalence of these FIX mutations in a given population.

Dextran sulfate of 5000 molecular weight (DXS 5000) is known to block complement activation as well as the intrinsic coagulation cascade by potentiation of C inhibitor. The effect of DXS 5000 on hyperacute rejection (HAR) was tested in pig-to-human xenotransplantation models. For in vitro testing, a cytotoxicity assay was used with the pig kidney cell line PK15 as target cells and fresh, undiluted human serum as antibody and complement source. Ex vivo pig lung perfusion was chosen to assess DXS 5000 in a physiologic model. Pig lungs were perfused with fresh, citrate-anticoagulated whole human blood to which 1 or 2 mg/ml DXS 5000 were added; the lungs were ventilated and the blood de-oxygenated. Pulmonary vascular resistance (PVR) and blood oxygenation (deltapO2) were monitored throughout the experiment. Autologous pig blood and human blood without DXS 5000 served as controls. In the PK 15 assay DXS 5000 led to a complete, dose-dependent inhibition of human serum cytotoxicity with an average IC50 of 43 +/- 18 microg/ml (n=8). Pig lungs perfused with untreated human blood (n=2) underwent HAR within 105 +/- 64 min, characterized by increased PVR, decrease of deltapO2, and generalized edema. Microscopically, capillary bleeding as well as deposition of human antibodies, complement and fibrin could be observed. Addition of DXS 5000 (n=4) prolonged lung survival to 170 +/- 14 min for 1 mg/ml and 250 +/- 42 min for 2 mg/ml. and PVR values as well as edema formation were comparable to control lungs that were perfused with autologous pig blood (n=2). Activation of complement (activation products in serum, deposition on lung tissue) and the coagulation system (fibrin monomers) were significantly diminished as compared to human blood without DXS 5000. Binding of anti-Gal antibodies was not influenced, and in vitro experiments showed no evidence of complement depletion by DXS 5000. In conclusion, DXS 5000 is an efficient complement inhibitor in pig-to-human xenotransplantation models and therefore a candidate for complement-inhibitory/anti-inflammatory therapy either alone or in combination with other substances and warrants further investigation.

We investigated the feasibility, quality and safety of patient self-control of oral anticoagulation. The patients were selected by their physicians on the basis of criteria such as compliance, skills and motivation. After theoretical and practical training they self-monitored and self-adjusted their anticoagulant dosage for 6 months by weekly self-measurement of their INR values using a capillary whole blood prothrombin time monitor (CoaguChek). Venous INR measurements once a month served as quality control. There were 51 study participants, who performed a median 5 INR measurements per month. 75.8% of all registered INR values were within the recommended individual INR target ranges. The coefficient of correlation between capillary (y) and venous (x) INR values was r = 0.87 (regression analysis y = 1.0 x -0.2). The concordance of capillary and venous INR values was 80% with respect to the individual INR target ranges. There were 5 minor bleeding episodes and no overt thromboembolic recurrences during the study period. In conclusion, the study demonstrated that patient self-control of oral anticoagulation is feasible and achieves a high percentage of INR values within the recommended target ranges. Therefore, self-control of oral anticoagulation can be offered to skilled and motivated patients as an alternative to physician-guided antiocogulation. However, specific training of these selected patients is necessary.

Coumarin hepatotoxicity resulting in a cholestatic or cytolytic hepatitis is a rare side effect in oral anticoagulant therapy, but has to be considered in any patient receiving coumarin treatment if hepatitis is diagnosed. Substitution with an other coumarin derivative is sometimes feasable, although cross-reactions between coumarin derivatives have been observed.

Background: The prothrombin time, also called thromboplastin time ("Quick"), is usually measured by using citrated plasma from venous blood. Recently, portable coagulation monitors have been developed which measure prothrombin time using non-anticoagulated capillary whole blood from a finger-stick. In the present study we evaluated the CoaguChek Plus coagulation monitor in comparison with a standard laboratory method in various patient groups: patients on oral anticoagulation with or without heparinisation, patients receiving heparin without oral anticoagulation, patients with a deficiency of one of the coagulation factors of the extrinsic or common pathway, and patients with liver disease. Furthermore, we studied the influence of the haemoglobin concentration on the test results., Method: Capillary prothrombin time was measured by using the portable coagulation monitor CoaguChek Plus and venous prothrombin time was assessed by using Thromborel S., Results: We found a correlation coefficient of 0.94 between capillary and venous INR values in 216 determinations from 167 patients. The slope of the regression line was 1.03, and the y-intercept 0.05, 93.5% of the results were within 0.9, 90.7% within 0.7, and 83.8% within 0.5 INR units. Similar results were obtained in patients on oral anticoagulation, patients with a deficiency of a factor of the extrinsic system and in patients with liver disease. Correlation and agreement were somewhat lower among patients on oral anticoagulation and simultaneous heparinisation (40 patients): correlation coefficient was 0.83, slope of the regression line was 0.87 and y-intercept was 0.27 INR units. No influence of the haemoglobin concentration on INR results could be demonstrated., Conclusion: Our results show the CoaguChek Plus coagulation monitor to be a valuable tool for measuring prothrombin time in patients on oral anticoagulation, in patients with liver disease to estimate the capacity of protein synthesis, and to screen for possible deficiencies of one of the coagulation factors of the extrinsic or common pathway. However, based on our preliminary data we cannot recommend the use of the CoaguChek Plus coagulation monitor in heparinised patients.

We investigated the influence of low molecular weight dextran sulfate (LMWdxs) and low molecular weight heparins (LMWH: dalteparin, enoxaparin and nadroparin) on the inhibition of FXIa by C1-inhibitor, alpha1-antitrypsin, alpha2-antiplasmin and antithrombin in a purified system and in plasma. The second order rate constant for inactivation of FXIa by C1-inhibitor, alpha1-antitrypsin, alpha2-antiplasmin, and antithrombin was 1.23, 0.056, 0.33 and 0.59 x 10(3) M(-1) s(-1), respectively. LMWdxs and LMWH dose-dependently increased the second order rate constant of the inactivation of FXIa by C1-inhibitor up to 39-fold. The second order rate constant of the inactivation of FXIa by antithrombin was increased up to 6-fold by LMWH, whereas LMWdxs had no effect. In plasma, FXIa was inactivated to about 50% by C1-inhibitor, while the other serpins contributed together to the remaining 50% of plasma's inhibitory capacity towards FXIa. In the presence of LMWdxs or LMWH, FXIa was inactivated in plasma to more than 90% by C1-inhibitor. LMWH at maximal therapeutic plasma levels enhanced the contribution of antithrombin to the inactivation of FXIa in plasma up to 5-fold. In conclusion, we found that the tested low molecular weight glycosaminoglycans dalteparin, enoxaparin and nadroparin and LMWdxs stimulate inactivation of FXIa by C1-inhibitor in a system using purified proteins as well as in plasma. Furthermore, LMWH but not LMWdxs slightly enhanced FXIa inhibition by antithrombin.

We report the case of a 76-year-old man with recurrent thromboses despite oral anticoagulation with phenprocoumon and low-grade chronic disseminated intravascular coagulation. Workup revealed a bronchial carcinoma (NSCCL) with hilar and mediastinal lymph node metastases. The clinical condition was consistent with Trousseau's syndrome. Based on reports in the literature, the therapy was changed to intravenous unfractionated heparin (UFH), which was effective in controlling the thrombotic coagulopathy. For practical reasons, despite a lack of evidence of its effectiveness in Trousseau's syndrome, therapy with UFH was changed to subcutaneous low-molecular-weight heparin (LMWH, nadroparine) in therapeutic doses of 100 IU/ kg body wt. 12 hourly. On an outpatient basis, five chemotherapy cycles were administered, and after metastases of the brain had been detected radiotherapy was initiated. Following 7.5 months of progressive neoplastic disease the patient died. He had remained free of thromboembolic complications under continued LMWH therapy during the last 6.5 months of his life. LMWH might be a convenient alternative to the established therapy with UFH in Trousseau's syndrome.

Chopard P, Dörffler-Melly J, Hess U, Wuillemin WA, Hayoz D, Gallino A, Bachli EB, Canova CR, Isenegger J, Rubino R, Bounameaux H (University Hospitals, Geneva; Inselspital, Bern; Kantonsspital, St Gall; Kantonsspital, Lucerne; CHUV, Lausanne; Ente Ospedaliero Cantonale Bellinzona-Locarno; Universitätsspital, Zurich; Angiologie Spitäler, Chur; and Aventis Pharma, Zurich; Switzerland). Venous thromboembolism prophylaxis in acutely ill medical patients: definite need for improvement.J Intern Med2005;257:352–357.To examine the frequency and adequacy of thromboprophylaxis in acutely ill medical patients hospitalized in eight Swiss medical hospitals.A cross-sectional study of 1372 patients from eight Swiss hospitals was carried out. After exclusion of patients (275) given therapeutic anticoagulation, 1097 patients were audited. The adequacy of thromboprophylaxis was assessed by comparison with predefined explicit criteria.Of 1097 patients, 542 (49.4%) received thromboprophylaxis. According to the explicit criteria, 644 (58.7%) should have been on prophylaxis (P < 0.001, when compared with the rate observed). The rate of prevention differed widely between hospitals (from 29.4 to 88.6%) with no difference between teaching and nonteaching hospitals. According to the explicit criteria, a substantial proportion (44.9%) of the patients who should have been treated were not. Conversely, 41.3% of the patients were unnecessarily treated.Even though the appropriateness of the explicit criteria used could be challenged, our data suggest that the current practice is associated with important uncertainty leading to both overuse and underuse of thromboprophylaxis in patients hospitalized in medical wards. More efforts are urgently needed to develop new or endorse existing explicit, evidence-based criteria and guidelines for thromboprophylaxis in this population of patients. [ABSTRACT FROM AUTHOR]

Five patients with hereditary angioedema (HAE) were studied during attacks and remission as were healthy controls. The high levels of C1/C1-INH complexes, low C4 and high ratio C4 activation products (C4bc)/C4 also differed significantly during remission compared to controls. During attacks C4bc/C4 increased (922-2007; P = 0.022, remission versus attacks, median values throughout), C2 and CH50 dropped (111-31%; P = 0,043 and 110-36%; P = 0.016, respectively), TCC (C5b-9) increased (0.88-1.23 AU/ml; P = 0.028). Cleavage of HK increased to be almost complete during attacks (20-90%; P = 0.009). While factor XIa/serpin-complexes did not increase, a more than twofold rise in thrombin/antithrombin-complexes (0.20-0.50 µg/l; P = 0.009) and in plasmin/alpha-2-antiplasmin-complexes (7.3-17 nmol/l; P = 0.028) was observed. For the first time cascade activation in HAE was studied simultaneously, and corroborates that attacks lead to activation of the kanikrein-kinin system, fibrinolysis and early part of the classical complement pathway. In addition, the authors present novel data of terminal complement and coagulation activation, the latter apparently not via FXIa. [ABSTRACT FROM AUTHOR]