| 1. |
- Hinz, P, et al.
(författare)
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[Informed consent on heparin-induced thrombocytopenia during thrombosis prophylaxis. A pilot study including 460 patients].
- 2003
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Ingår i: Deutsche Medizinische Wochenschrift. - : Georg Thieme Verlag KG. - 0012-0472 .- 1439-4413. ; 128:42, s. 2184-8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The practicability and acceptance of written information about heparin thrombosis prophylaxis and the associated risk of heparin-induced thrombocytopenia (HIT) was evaluated in a pilot study. PATIENTS AND METHODS: All patients consecutively admitted to the department of trauma- and reconstructive surgery at the Ernst-Moritz-Arndt-University, Greifswald, Germany, with an indication for heparin thrombosis prophylaxis were give written information about thrombosis prophylaxis and the undesired drug effect HIT. After this, acceptance was evaluated using a standardized questionnaire. Primary endpoint was refusal of heparin for thrombosis prophylaxis, secondary endpoint acceptance and comprehensibility of the information. RESULTS: None of the 460 patients included in the study subsequently refused thrombosis prophylaxis with heparin. The majority welcomed the information and thought it should be given to all patients that are about to be treated with heparin. Only 0.9 % of patients judged comprehensibility of the information to be insufficient. Anticipation of imminent heparin therapy (good/very good in 90 %) and appreciation of the quality of care was not judged to be unacceptable by any patient. CONCLUSIONS: The present study demonstrates that giving information about heparin-induced thrombocytopenia during explanation of the risks and benefits of heparin thrombosis prophylaxis is feasible. This information--given in writing in our pilot study--was judged by patients to be comprehensible and necessary and did not lead to refusal of treatment. Lower incidence of HIT with use of low molecular weight heparins should be considered in the choice of drug for thrombosis prophylaxis.
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| 2. |
- Eichler, P, et al.
(författare)
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Antihirudin antibodies in patients with heparin-induced thrombocytopenia treated with lepirudin : incidence, effects on aPTT, and clinical relevance.
- 2000
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Ingår i: Blood. - 0006-4971 .- 1528-0020. ; 96:7, s. 2373-8
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Tidskriftsartikel (refereegranskat)abstract
- Hirudin, a potent and specific thrombin inhibitor, is a protein of nonhuman origin and therefore potentially immunogenic. The primary objectives of this investigation were to determine the incidence of antihirudin antibodies (ahir-ab) in patients with heparin-induced thrombocytopenia (HIT) who received lepirudin as parenteral anticoagulation and to determine the incidence of death, limb amputation, new thromboembolic complications (TECs), and major hemorrhage in patients who had ahir-ab, compared with patients who were ahir-ab negative. The investigation used data from 2 prospective multicenter studies with the same study protocol, in which HIT patients received 1 of 4 intravenous lepirudin dosage regimens. The treatment duration was 2 to 10 days. Ahir-ab were determined by a newly developed enzyme-linked immunosorbent assay (ELISA). Eighty-seven of 196 evaluable patients (44.4%) had ahir-ab of the IgG class. Development of ahir-ab was dependent on the duration of treatment (ahir-ab-positive patients 18.6 days vs ahir-ab-negative patients 11.8 days; P =.0001). Fewer ahir-ab-positive than ahir-ab-negative patients died (P =.001). Ahir-ab did not cause an increase in limb amputation (P =.765), new TECs (P >.99), or major bleedings (P =.549). In 23 of 51 (45.1%) evaluable patients in whom ahir-ab developed during treatment with lepirudin ( = 12% of all lepirudin treated patients), the ahir-ab enhanced the anticoagulatory effect of lepirudin. Ahir-ab are frequent in patients treated with lepirudin for more than 5 days. Ahir-ab are the first example for a drug-induced immune response causing enhanced activity of a drug. Therefore, during prolonged treatment with lepirudin, anticoagulatory activity should be monitored daily to avoid bleeding complications.
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| 3. |
- Greinacher, A, et al.
(författare)
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Anaphylactic and anaphylactoid reactions associated with lepirudin in patients with heparin-induced thrombocytopenia.
- 2003
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Ingår i: Circulation. - 0009-7322 .- 1524-4539. ; 108:17, s. 2062-5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Lepirudin (Refludan) is a hirudin derivative. It is a direct thrombin inhibitor obtained by recombinant technology from the medicinal leech and is approved for treatment of heparin-induced thrombocytopenia complicated by thrombosis. Because 3 cases of fatal anaphylaxis possibly associated with use of lepirudin have been reported, we initiated an investigation of putative lepirudin-associated anaphylaxis. METHODS AND RESULTS: Aided by the manufacturer (Schering AG, Berlin, Germany), we used the lepirudin study databases to identify all patients in whom possible anaphylaxis/severe allergy was recorded from 1994 to September 2002. The 26 possible cases identified were reviewed independently by 2 investigators. After excluding patients with mild skin reactions, reactions likely caused by concomitant medications, poorly documented cases, and reactions that did not correspond temporally with lepirudin use, there remained 9 patients judged to have had severe anaphylaxis in close temporal association with lepirudin. All reactions occurred within minutes of intravenous lepirudin administration, with 4 fatal outcomes (3 acute cardiorespiratory arrests, 1 hypotension-induced myocardial infarction). In these 4 cases, a previous uneventful treatment course with lepirudin was identified (1 to 12 weeks earlier). We recorded high-titer IgG-anti-lepirudin antibodies in an additional patient with anaphylaxis. Because lepirudin has been used in approximately 35 000 patients, the risk of anaphylaxis is approximately 0.015% (5 of 32 500) on first exposure and 0.16% (4 of 2500) in reexposed patients (7.5% estimated reexposures). CONCLUSIONS: Lepirudin can cause fatal anaphylaxis, particularly in patients who are treated within 3 months of a previous exposure. The overall risk/benefit assessment of lepirudin as a treatment for heparin-induced thrombocytopenia remains favorable.
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| 4. |
- Greinacher, A, et al.
(författare)
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Drug-induced and drug-dependent immune thrombocytopenias.
- 2001
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Ingår i: Reviews in Clinical and Experimental Hematology. - 1127-0020 .- 1825-151X. ; 5:3, s. 166-200; discussion 311
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Tidskriftsartikel (refereegranskat)abstract
- Thrombocytopenia is a frequent comorbid condition in many in hospital patients. In some patients, drugs are the cause of low platelet counts. While cytotoxic effects of anti-tumor therapy are the most frequent cause, immune mechanisms should also be considered. This review addresses thrombocytopenias in four groups. Heparin-dependent thrombocytopenia (HIT), by far the most frequent drug-induced immune-mediated type of thrombocytopenia, has a unique pathogenesis and clinical consequences. HIT is a clinicopathological syndrome in which antibodies mostly directed against a multimolecular complex of platelet factor 4 and heparin cause paradoxical thromboembolic complications. The mechanisms through which heparin can enhance thrombin generation are discussed and treatment alternatives for affected patients are presented in detail. It is of primary importance to recognize these patients as early as possible and to substitute heparin with a compatible anticoagulatory drug, such as hirudin, danaparoid or argatroban. Patients seem to benefit from therapeutic doses of alternative treatment rather than from low-dose prophylactic doses. With the increasing use of glycoprotein (GP) IIb/IIIa inhibitors in patients with acute coronary syndromes, thrombocytopenias are increasingly recognized as an adverse effect of these drugs. Up to 4% of treated patients are affected. Most important, pseudothrombocytopenia, a laboratory artefact, is as frequent as real drug-induced thrombocytopenia and must be excluded before changes in treatment are considered. The pathogenesis of these thrombocytopenias is still debated; an immune mechanism involving preformed antibodies is likely. However, since these antibodies are also detectable in a high percentage of normal controls and of patients not developing thrombocytopenia, their impact is still unclear. Patients with real thrombocytopenia are at an increased risk of bleeding; treatment consists of cessation of the GP IIb/IIIa inhibitor and platelet transfusions in cases of severe hemorrhage. Classic immune thrombocytopenia can be induced by some drugs, e.g. gold, which trigger anti-platelet antibodies indistinguishable from platelet autoantibodies found in autoimmune thrombocytopenia. Drug-induced and drug-dependent immune thrombocytopenia is induced by antibodies recognizing an epitope on platelet GP formed after binding of a drug to a platelet glycoprotein. Still unresolved is whether antibody binding is the consequence of a conformational change of the antigen, the antibody, or both. These antibodies typically react with monomorphic epitopes on platelet GP, but only in the presence of the drug or a metabolite. Although several platelet GP have been identified as antibody target (GPIb/IX, GPV, GP IIb/IIIa), antibodies in an individual patient are highly specific for a single GP. Clinically, these patients present with very low platelet counts and acute, sometimes severe, hemorrhage. Treatment is restricted to withdrawal of the drug and symptomatic treatment of bleeding.
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| 5. |
- Greinacher, A, et al.
(författare)
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Heparin-induced thrombocytopenia with thromboembolic complications : meta-analysis of 2 prospective trials to assess the value of parenteral treatment with lepirudin and its therapeutic aPTT range.
- 2000
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Ingår i: Blood. - 0006-4971 .- 1528-0020. ; 96:3, s. 846-51
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Tidskriftsartikel (refereegranskat)abstract
- This meta-analysis focuses on 2 prospective studies in patients with heparin-induced thrombocytopenia (HIT) and thromboembolic complication (TEC) who were treated with lepirudin (n = 113). Data were compared with those of a historical control group (n = 91). The primary endpoint (combined incidence of death, new TEC, and limb amputation) occurred in 25 lepirudin-treated patients (22.1%; 95% CI, 14.5%-29.8%): 11 died (9.7%; 95% CI, 4.9%-16.8%), 7 underwent limb amputation (6.2%; 95% CI, 2.5%-12.3%), and 12 experienced new TEC (10.6%; 95% CI, 5.8%-18.3%). The risk was highest in the period between diagnosis of HIT and the start of lepirudin therapy (combined event rate per patient day 6.1%). It markedly decreased to 1.3% during lepirudin treatment and to 0.7% in the posttreatment period. From the start of lepirudin therapy to the end of follow-up, lepirudin-treated patients had consistently lower incidences of the combined endpoint than the historical control group (P =.004, log-rank test), primarily because of a reduced risk for new TEC (P =. 005). Thrombin-antithrombin levels in the pretreatment period (median, 43.9 microg/L) decreased after the initiation of lepirudin (at 24 hours +/- 6 hours; median, 9.18 microg/L.) During treatment with lepirudin, aPTT ratios of 1.5 to 2.5 produced optimal clinical efficacy with a moderate risk for bleeding, aPTT ratios lower than 1. 5 were subtherapeutic, and aPTT levels greater than 2.5 were associated with high bleeding risk. Bleeding events requiring transfusion were significantly more frequent in patients taking lepirudin than in historical control patients (P =.02). In conclusion, this meta-analysis provides further evidence that lepirudin is an effective and acceptably safe treatment for patients with HIT.
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| 6. |
- Greinacher, A, et al.
(författare)
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Recombinant hirudin in clinical practice : focus on lepirudin.
- 2001
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Ingår i: Circulation. - 0009-7322 .- 1524-4539. ; 103:10, s. 1479-84
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Tidskriftsartikel (refereegranskat)abstract
- Clinical applications for recombinant hirudins have been investigated for the past 10 years. The first indication for which a hirudin-lepirudin-has been approved is treatment of heparin-induced thrombocytopenia (HIT). Also, the recently completed trials for use of lepirudin in unstable angina indicate a potentially new indication. This review describes pharmacology and clinical applications of lepirudin with an emphasis on HIT and unstable angina. An overview of usage of lepirudin in acute coronary syndromes is given, as well as a summary of rare indications for lepirudin, such as extracorporeal circulation, for which comprehensive data are lacking.
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| 7. |
- Lubenow, Norbert, et al.
(författare)
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Drugs for the prevention and treatment of thrombosis in patients with heparin-induced thrombocytopenia.
- 2001
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Ingår i: American Journal of Cardiovascular Drugs. - 1175-3277 .- 1179-187X. ; 1:6, s. 429-43
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Tidskriftsartikel (refereegranskat)abstract
- Most patients with heparin-induced thrombocytopenia (HIT), a serious adverse effect of heparin mediated by platelet-activating heparin-dependent antibodies, require alternative anticoagulation. This is because HIT is highly prothrombotic and is characterized by markedly increased thrombin generation. Unfractionated heparins seem to induce HIT more often than low molecular weight heparins. There are three anticoagulants for which there is an emerging consensus for their efficacy in management of HIT, and which are currently approved for treatment of HIT in several countries: the recombinant hirudin, lepirudin, a direct thrombin inhibitor; the synthetic direct thrombin inhibitor, argatroban; and the heparinoid, danaparoid sodium, mainly exhibiting antifactor-Xa activity. Recommendations for optimal use of these drugs in HIT are given in this review stressing the need for immediate treatment of patients with HIT without awaiting laboratory diagnosis. Hirudin, the drug for which most data from prospective trials exists, can be safely and effectively used in patients with HIT, its dramatically increased elimination half-life in patients with renal failure being the most important drawback. Argatroban, which is mainly eliminated by the liver, could be used preferentially in such patients with renal impairment. Interference with the international normalized ratio makes oral anticoagulation, which is necessary in many patients with HIT, problematic. Activated partial thromboplastin time is sufficient to monitor lepirudin and argatroban treatment in most cases. Danaparoid sodium, with an antifactor-X activity half-life of about 24 hours seems to be best suited for thrombosis prophylaxis in patients with HIT. In some patients monitoring by determining antifactor-Xa activity is necessary. No antidote is available for any of the drugs discussed, and bleeding complications are the most important adverse effects. In situations such as hemodialysis or cardiopulmonary bypass, not only the characteristics of the drug in use itself, but also availability of monitoring methods play an important role. Adjunctive treatments have not been systematically evaluated and should be used cautiously. Recent data suggest that re-exposure of patients with a history of HIT with heparin, for example during cardiopulmonary bypass, can be well tolerated provided no circulating HIT antibodies are detectable at the time of re-exposure, and heparin is strictly avoided pre- and postoperatively.
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| 8. |
- Lubenow, Norbert, et al.
(författare)
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Heparin-induced thrombocytopenia : recommendations for optimal use of recombinant hirudin.
- 2000
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Ingår i: BioDrugs. - 1173-8804 .- 1179-190X. ; 14:2, s. 109-25
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Tidskriftsartikel (refereegranskat)abstract
- Recombinant hirudins have a definite role in the treatment of patients with heparin-induced thrombocytopenia (HIT). The most important adverse effects are haemorrhages and the induction of antihirudin antibodies. Major haemorrhages were not significantly increased in patients with HIT compared with a historical control group, but prospective data comparing hirudin and heparinoids such as danaparoid are lacking. The definition of the optimal method for monitoring and the availability of an antidote for hirudin would probably increase safety with this drug. To date, haemofiltration using high-flux filter systems is the only way to remove an overdosage of hirudin from the circulation. In patients with renal impairment requiring hirudin treatment, it therefore seems safer to start with a low dose that is subsequently adjusted according to the activated partial prothromboplastin time or ecarin clotting time. Even in special circumstances, such as cardiopulmonary bypass or dialysis, hirudins can be applied successfully if care is taken to monitor their effects meticulously. There are many other indications in which hirudins have shown feasibility (e.g. acute coronary syndromes) but available data preclude definite conclusions.
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| 9. |
- Lubenow, Norbert, et al.
(författare)
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[Hirudins in the treatment of heparin-induced thrombocytopenia and in thrombosis prophylaxis].
- 2002
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Ingår i: Hämostaseologie. - 0720-9355. ; 22:3, s. 44-54
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Tidskriftsartikel (refereegranskat)abstract
- Approved indications for the recombinant hirudins lepirudin (Refludan(R)) und desirudin (Revasc(R)) are therapy of heparin-induced thrombocytopenia (HIT) and thrombosis prophylaxis following knee or hip replacement surgery. Kidney function dependent pharmacokinetics and their capability of inducing antibodies directed against hirudin are characteristic of this class of drugs. However, close dose-monitoring allows safe and effective use of both compounds. While lepirudin is used widely, besides danaparoid, for treatment of HIT, desirudin has not yet been widely accepted for thrombosis prophylaxis following knee or hip replacement surgery.
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| 10. |
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