[Prophylaxis of venous thromboembolism and anticoagulation bridging. Strategies in otorhinolaryngology]. / Thromboembolieprophylaxe und überbrückende Antikoagulation. Strategien in der HNO-Heilkunde.

Various interdisciplinary guidelines recommend that in-patients at risk of venous thromboembolism should receive pharmacologic prophylaxis. Among the anticoagulants low-molecular-weight heparins (LMWH) and fondaparinux can be considered the medications of choice because of the favorable pharmacokinetic properties when compared with unfractionated heparin. Treatment with vitamin K antagonists has to be interrupted in patients undergoing major surgery or invasive procedures. Oral anticoagulation has to be temporarily replaced by short-acting anticoagulants such as LMWH in order to prevent thromboembolic complications (anticoagulation bridging). Although LMWHs have not been approved for this clinical setting their efficacy and safety has been demonstrated in several recent studies. Detailed recommendations for prophylaxis of venous thromboembolism in otorhinolaryngology are lacking although numerous surgical procedures are considered to be associated with a significant risk of thromboembolism. A strategy for pharmacologic prophylaxis of venous thromboembolism and anticoagulation bridging in otorhinolaryngology is proposed.

[Haemostatic testing prior to elective surgery? Yes!]. / Laboranalytischer Ausschluss einer hämorrhagischen Diathese vor elektiven Eingriffen? Ja!

Haemorrhagic disorders must be excluded prior to any operation or other invasive procedure that has the potential to involve serious bleeding. When assessing the individual risk of bleeding, screening tests of hemostasis must be combined with the patient's clinical history and symptoms, and any history of bleeding must be explored under direct medical supervision using a standardized questionnaire. However, this bleeding history is neither very specific, nor is it particularly sensitive. Screening tests that have been found to be useful include platelet count, activated partial thrombo plastin time (aPTT), prothrombin time (PT) and clottable fibrinogen. No reliable, sensitive and specific screening test is however available today to screen for platelet dysfunction or von Willebrand disease. A specialized coagulation laboratory should be involved when the bleeding history or laboratory screening indicate a potential haemorrhagic disorder.

[Continuous lumbar epidural anesthesia: insertion a patient with unrecognized classical hemophilia A]. / Kontinuierliche lumbale Epiduralanästhesie: Anlage bei einem Patienten mit unerkannter Hämophilie A.

This report describes a case where a continuous lumbar epidural anesthesia was inserted for an operation in a patient with classical hemophilia which was unknown at the time of catheter insertion. In addition to an exact description of the intervention, the anamnesis and laboratory contraindications for epidural anesthesia are discussed. Furthermore, the necessity of preoperative investigations and their value when an epidural anesthesia is planned are also discussed.

Preservation of in vitro function of platelets stored in the presence of a synthetic dual inhibitor of factor Xa and thrombin.

BACKGROUND: The use of citrate anticoagulant limits the clinical significance of platelet function tests. Thrombin inhibitors cannot prevent thrombin-induced platelet activation completely. We examined the influence of benzylsulfonyl-d-Arg-Pro-4-amidinobenzylamide (BAPA), a dual inhibitor of Factor Xa (FXa) and thrombin, on platelet responsiveness to agonists when measured between 2 and 24 h after venipuncture. METHODS: Blood samples from 36 individuals were anticoagulated with citrate and BAPA, respectively. Turbidimetric platelet aggregometry (TPA) and impedance platelet aggregometry (IPA), a whole blood platelet counting assay for measuring platelet aggregation (PCA), and Platelet Function Anlayzer-100 (PFA-100 closure times (CTs) were determined after whole blood storage between 2 and 24 h after venipuncture. Native whole blood was studied over 48 h to determine the inhibition of thrombin generation by BAPA, hirudin and melagatran. RESULTS: BAPA inhibited thrombin generation completely for 48 h, while hirudin and melagatran did not. The use of citrate resulted in significantly reduced TPA induced by arachidonic acid (AA) or adenosine 5'-diphosphate (ADP), and significantly reduced IPA regardless of agonist when measured 10 and 24 h after blood collection. PCA ratios in citrated blood also dropped significantly 10 and 24 h after venipuncture. The length of storage of BAPA-anticoagulated blood samples over 24 h had no significant influence on any platelet response. The reproducibility of platelet function assay results obtained from BAPA-anticoagulated samples was significantly better than corresponding data from citrated blood. CONCLUSION: TPA, IPA, PCA or PFA-100 CTs remain stable for 24 h when whole blood is anticoagulated with a dual inhibitor of FXa and thrombin. This would greatly simplify the shipment of samples for platelet function testing.

[Intracranial bleeding in acquired hemophilia]. / Intrakranielle Blutung bei erworbener Hemmkörperhämophilie.

Acquired hemophilia is a rare complication in autoimmune disorders and malignancies. It can result in bleedings into skin and muscle, whereas intracranial hemorrhage in adults has so far not been described. We report a patient with acute intracerebral hemorrhage due to acquired hemophilia with factor VIII inhibition. The patient was treated with recombinant factor VIIa and open hematoma evacuation followed by administration of cortisone and cyclophosphamide. After good initial recovery, intracerebral rebleeding occurred and the patient died from brainstem compression.

A prospective trial on the safety of long-term intensive plasmapheresis in donors.

BACKGROUND AND OBJECTIVES: There are still concerns about the safety of long-term intensive donor plasmapheresis, because the reasons that donors drop out of plasmapheresis programmes have not been determined in prospective studies. MATERIALS AND METHODS: Seventy-two donors were switched from a moderate plasmapheresis programme to an intensive plasmapheresis programme and observed over a 3-year period. In addition to measuring total serum protein (TSP), albumin, immunoglobulin G (IgG) and haemoglobin (Hb) levels, parameters of iron metabolism and blood coagulation, and biochemical cardiovascular risk markers, were determined at baseline and at every 15th donation. We also collected statements from donors who dropped out of the plasmapheresis programme about their reasons for withdrawal. RESULTS: Dropouts were predominantly related to socioeconomic (n = 34) or medical reasons not related to plasma donations (n = 8). Three donors had to drop out when their TSP levels fell below threshold for the third time within a 5-week period. At baseline, donors had significantly lower TSP, albumin, IgG, Hb and ferritin levels than gender-matched and age-matched non-donor controls. However, subsequent intensive plasmapheresis over 3 years did not impair the individuals' ability to donate plasma. TSP, IgG, Hb, ferritin, transferrin, cardiovascular risk markers and parameters of blood coagulation did not change significantly during the observation period. CONCLUSIONS: The reasons why donors cease to participate in intensive plasmapheresis programmes are predominantly not directly related to the plasma donation itself.

The impact of two whole blood inline filters on markers of coagulation, complement and cell activation.

BACKGROUND AND OBJECTIVES: There exists a current lack of information about the impact of different inline filters, used for the leucoreduction of whole blood (WB), on the levels of clotting factors and markers of coagulation, complement and cell activation in plasma. Only a few small comparisons of different types of WB inline filters have been published to date. MATERIALS AND METHODS: This study compared two plasma types of 200 units each. Both study groups were derived from WB, inline-filtered and held for 2 h at 20 degrees between donation and filtration. Then, 200 units (Group A) were filtered using a positively charged polyester filter (Baxter RZ2000) and the other 200 units (Group B) were filtered using an uncharged polyester filter (Fresenius). After filtration, both groups were analysed for fibrinogen, factors V and VIII:C (FV and FVIII:C, respectively), immunoglobulin G (IgG), residual leucocytes and platelets, and markers of coagulation, complement and cell activation. Predonation plasma samples from CPDA1-anticoagulated blood were obtained from 100 different individuals and served as controls. RESULTS: WB inline filtration did not influence fibrinogen, FV, FVIII:C or IgG levels. Neither filter induced thrombin or fibrin formation. The charged filter caused substantial complement activation and neutrophil elastase and platelet factor 4 release. In contrast, the plasma filtered through the uncharged filter showed markedly lower levels of C3a-desArg, C5a, neutrophil elastase and platelet factor 4, and moderately reduced levels of prothrombin fragments 1+2 and D-dimer, compared with controls. CONCLUSIONS: Filter type has a significant impact on the quality of plasma derived from WB filtered through inline filtration systems. Some filters produce substantial coagulation and complement activation and cell release, while others appear to reduce the plasma levels of activation markers. The clinical significance of these findings remains to be determined.

[Platelet function tests for monitoring of acetylsalicylic acid: clinical significance in antiplatelet treatment]. / Plättchenfunktionstests zum Monitoring der Azetylsalizylsäuretherapie acid: Klinische Wertigkeit bei plättchenfunktionshemmender Behandlung.

Several studies have demonstrated with the use platelet function tests (PFT) that subgroups of patients under acetylsalicylic acid (ASA) fail to produce the anticipated antiplatelet effect. This phenomenon as well as the clinical failure of ASA to protect patients from thromboembolic complications has been termed ASA resistance (AR) or ASA nonresponsiveness. Several subtypes of AR can be distinguished by PFT. The following PFT were used to characterize AR: optical aggregometry, platelet aggregation in whole blood, platelet function analyzer (PFA-100), platelet reactivity test or platelet aggregate ratio, flow cytometry and thromboxane B(2) generation. All PFT have in common that their widespread clinical use is substantially limited due to complex preanalytic factors, reduced specificity and poor reproducibility. PFT are not interchangeable for monitoring antiplatelet treatment. Three prospective clinical trials revealed a possible relationship between AR and subsequent cardiovascular events. There is a need for a simple and reliable assay for predicting the clinical efficacy of antiplatelet therapy. Recent data demonstrate that none of the currently available assays including the PFA-100 system are capable to accomplish these objectives.

The impact of different intensities of regular donor plasmapheresis on humoral and cellular immunity, red cell and iron metabolism, and cardiovascular risk markers.

BACKGROUND AND OBJECTIVES: Major studies are still lacking on the impact of differing intensities of long-term donor plasmapheresis, not only on total serum protein, albumin and immunoglobulin G (IgG), but also on humoral and cellular immunity, red cell and iron metabolism, and biochemical cardiovascular risk markers. MATERIALS AND METHODS: Three groups of donors, comprising 483 individuals undergoing differing intensities of long-term serial plasmapheresis, were entered into a cross-sectional study. A fourth control group consisted of 100 non-donors. In addition to measuring total protein, albumin and IgG levels, we determined parameters of humoral and cellular immunity, red cell and iron metabolism and recognized biochemical cardiovascular risk factors. RESULTS: The median annual net amount of plasma donated by the three donor groups was 37, 16 and 10 l, respectively (P < 0.0001). Donors had significantly lower total serum protein, albumin and IgG levels than non-donors (P < 0.0001), but the intensity of plasmapheresis had no influence on those parameters. Like non-donors, all plasma donors had normal humoral and cellular immunity. No increased rates of iron store depletion were observed in the three groups of plasma donors. Plasma donors were not at increased cardiovascular risk. CONCLUSIONS: Regular donor plasmapheresis of up to 45 l of plasma per year appears to be as safe as more moderate plasmapheresis programmes, with respect to the parameters analysed in this study. Individuals donating under these conditions did not develop impaired humoral and cellular immunity, iron store depletion, or increased cardiovascular risk with regard to established biochemical risk markers. Prospective studies are required to determine more exactly than in retrospective analyses the reasons why donors withdraw from plasmapheresis programmes.

Effects of solvent/detergent-treated plasma and fresh-frozen plasma on haemostasis and fibrinolysis in complex coagulopathy following open-heart surgery.

BACKGROUND AND OBJECTIVES: Solvent/detergent-treated plasma (SDP) contains markedly lower protein S (PS) and plasmin inhibitor (PI) activity than standard fresh-frozen plasma (FFP). It has also been reported that SDP contains no alpha(1)-antitrypsin. Despite the lack of clinical data, it is suspected that SDP may be less effective than FFP in the treatment of complex coagulopathies. We therefore conducted a prospective trial to study the impact of SDP and FFP on haemostasis and fibrinolysis in complex coagulopathy after open-heart surgery. MATERIALS AND METHODS: Patients received either 600 ml of SDP (n = 36) or 600 ml of FFP (n = 31) at an infusion rate of 30 ml/min. The following parameters were measured before treatment and 60 min after termination of plasma infusion: prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, factor VIII, antithrombin, protein C (PC), free PS and PS activity, prothrombin fragments F1+2 (F1+2), D-dimers (DD), fibrinogen degradation products (FDP), plasmin-plasmin inhibitor complexes (PPI), plasminogen, PI and alpha(1)-antitrypsin. RESULTS: The rise in fibrinogen, factor VIII, antithrombin, PC, free PS, alpha(1)-antitrypsin and plasminogen, and the decrease in PT and APTT, did not significantly differ between the two study arms. However, PS activity did not increase after SDP infusion but did show a significant elevation after infusion with FFP. PI declined significantly after SDP and remained uninfluenced by FFP. Neither SDP nor FFP had any significant influence on F1+2, DD or FDP. However, a significant decrease in PPI levels caused by both types of plasma indicated a reduction in hyperfibrinolysis. Clinical haemostasis evaluation revealed no significant difference between the two treatment regimens. No adverse reactions were observed. CONCLUSION: With the exception of PS and PI, SDP and FFP improved haemostasis and fibrinolysis to a similar degree. The clinical significance of these findings has to be determined in patients with severe acquired PS and PI deficiency requiring plasma transfusions.

[Gene polymorphisms of hemostasis and coronary risk]. / Genpolymorphismen der Hämostase und Koronarrisiko.

Hemostatic disorders are substantially involved in the pathogenesis of coronary heart disease and acute coronary syndromes. In addition to biochemical markers, gene polymorphisms of hemostasis have been intensively studied in terms of their association with coronary risk. These include polymorphisms of the genes of platelet glycoproteins, fibrinogen, prothrombin, factors V, VIII and XIII, plasminogen activator inhibitor-1 and tissue-type plasminogen activator. An association of a certain gene polymorphism with an increased coronary risk has usually been demonstrated in retrospective case-control studies. However, numerous clinical studies have not yet been able to identify any of these polymorphisms as unequivocal risk factors of coronary heart disease or acute coronary syndromes. These inconsistencies are mainly due to the complexity of the pathogenesis of coronary heart disease and the minor contribution of a single polymorphism to total coronary risk. This review reports on essential requirements of future studies as a prerequisite to improve our understanding of the genetic basis of coronary heart disease.

The impact of the intensity of serial automated plasmapheresis and the speed of deep-freezing on the quality of plasma.

BACKGROUND: Data are lacking on the impact that the intensity of serial donor plasmapheresis has on the quality of source plasma. A study was conducted to examine the quality of source plasma produced by intensive plasmapheresis and slow deep-freezing and to compare it to source plasma manufactured by moderate plasmapheresis and rapid freezing. STUDY DESIGN AND METHODS: Seventy-five plasma samples from intensive plasmapheresis programs (Group 1) and 75 plasma units from moderate plasmapheresis programs (Group 2) were examined. The plasma had been deep-frozen either slowly at -30 degrees C in walk-in freezers (Group 1) or rapidly within 1 hour to a core temperature below -30 degrees C (Group 2). Determinations were made of the plasma levels of citrate; total protein; albumin; IgG; fibrinogen; factors II, V, VII, VIII, and IX; vWF; antithrombin; protein C; D-dimers; and prothrombin fragments 1+ 2. RESULTS: Plasma units of Group 2 contained substantially greater levels of citrate, IgG, FVIII, and FV than samples of Group 1 (p<0.0001). Plasma levels of total protein, albumin, and fibrinogen also were higher in Group 2 (p<0.0001, p = 0.007, and p = 0.006, respectively). Neither plasmapheresis intensity nor freezing procedure had any influence on the levels of factors II, VII, and IX, antithrombin, or protein C. There was no evidence of substantial coagulation activation in the plasma units of either group. However, higher FVIII clotting activity/chromogenic substrate activity ratios in rapidly frozen plasmas and a significant correlation between these ratios and prothrombin fragment 1+ 2 levels suggest that rapid freezing yields both more native FVIII and greater partial activation of FVIII. CONCLUSION: Source plasma collected from donors undergoing intensified plasmapheresis contains markedly lower levels of IgG than plasma units produced by moderate serial plasmapheresis. The combination of intensified plasmapheresis and slower freezing of source plasma results in substantially lower levels of FV and FVIII than does moderate plasmapheresis with rapid freezing. Prospective studies should establish the optimum conditions required for the safe and economic production of source plasma for fractionation.