vitamin-k-semiquinone-radical and bivalirudin

Anticoagulant drugs belong to the group of antithrombotic agents and are successfully used in the prophylaxis and treatment of thromboembolic disorders. The use of anticoagulants in the prevention of deep venous thrombosis has significantly lowered the risk of venous thrombosis and fatal pulmonary embolisms even in high-risk situations such as orthopedic surgery. Anticoagulants play a central role in the treatment of acute venous thrombosis and in the prevention of recurrent events. Long-term anticoagulation therapy with orally active anticoagulants significantly reduces the risk of thromboembolic complications in patients showing cardiac arrhythmias. Whereas a few years ago heparins and vitamin K antagonists were the dominant anticoagulants, today a wide range of anticoagulants with improved pharmacological profiles are available. It remains an open question whether these new anticoagulants will improve the efficacy, safety, and acceptance of anticoagulant treatment approaches.

Topics: Administration, Oral; Anticoagulants; Antithrombins; Arginine; Arrhythmias, Cardiac; Blood Coagulation Tests; Factor Xa Inhibitors; Hemorrhage; Heparin; Heparinoids; Hirudins; Humans; Infusions, Intravenous; Orthopedic Procedures; Peptide Fragments; Pipecolic Acids; Postoperative Complications; Pulmonary Embolism; Recombinant Proteins; Risk Factors; Secondary Prevention; Sulfonamides; Thromboembolism; Treatment Outcome; Venous Thrombosis; Vitamin K

This review describes some natural proteins, which can be employed, either as factor concentrates derived from human plasma or as recombinant drug, to modulate the coagulation system. I will address some biochemical characteristics and the physiological role of von Willebrand factor, the coagulation factors of the extrinsic and intrinsic pathways, and the physiological anticoagulant protein C. In addition, I will detail the pharmacological compounds, which are available for influencing or substituting the coagulation proteins: desmopressin (DDAVP), single coagulation factor concentrates, prothrombin complex concentrates, and protein C concentrate. In particular, I will address some treatment topics of general medical interest, such as the treatment of massive bleeding, the correction of the coagulopathy induced by vitamin K-antagonists in patients with cerebral haemorrhage, and of the coagulopathy of meningococcemia. Finally, I will describe some properties and practical clinical applications of the recombinant anticoagulans lepirudin and bivalirudin, which are derived from hirudin, the natural anticoagulant of the medical leech.

Topics: Anticoagulants; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Proteins; Cerebral Hemorrhage; Hemorrhage; Hirudins; Humans; Peptide Fragments; Protein C; Recombinant Proteins; Vitamin K; von Willebrand Factor

Accomplishing a successful percutaneous coronary intervention in a patient with a suspected or diagnosed heparin-induced thrombocytopenia (HIT) requires the selection of an appropriate alternative anticoagulant and a thorough assessment of bleeding and thrombotic risks. In this review, we suggest an evidence-based management algorithm that takes into account the clinical phase of HIT (acute, recent, and remote HIT) and the associated risk when patients present with acute coronary syndrome. The algorithm also integrates preventive measures directed at decreasing the bleeding risk associated with the antithrombotic and invasive therapies used for HIT and percutaneous coronary intervention.

Topics: Algorithms; Angioplasty, Balloon, Coronary; Anticoagulants; Arginine; Chondroitin Sulfates; Comorbidity; Dermatan Sulfate; Drug Therapy, Combination; Fibrinolytic Agents; Fondaparinux; Heparin; Heparinoids; Heparitin Sulfate; Hirudins; Humans; Myocardial Infarction; Peptide Fragments; Pipecolic Acids; Polysaccharides; Recombinant Proteins; Sulfonamides; Syndrome; Thrombocytopenia; Vitamin K

Topics: Animals; Fibrinolytic Agents; Hemostasis; Heparin; Heparin, Low-Molecular-Weight; Hirudins; Humans; Peptide Fragments; Platelet Aggregation Inhibitors; Platelet Glycoprotein GPIIb-IIIa Complex; Receptors, Purinergic P2; Recombinant Proteins; Thrombosis; Vitamin K

Heparin-induced thrombocytopenia (HIT, type II) is an immune-mediated disorder due to antibodies formed against heparin-platelet factor 4 complexes, usually appearing at days 5 to 14 after initiation of heparin. It is important to recognize HIT because heparin prophylaxis or treatment paradoxically associates with new venous and/or arterial thrombosis. Early clinical suspicion and diagnosis together with proper pharmacotherapy and close laboratory monitoring are the cornerstones for successful management. This includes monitoring of Thrombocytopenia, its Timing to heparin administration, appearance of new Thrombosis or resistance to treatment, and differential diagnosis by exclusion of o Ther causes (the 4T's). Specific attention should be paid to the absence or presence of thrombosis and to tailoring thromboprophylaxis or anticoagulant therapy with a nonheparin alternative. Even in the absence of HIT-associated thrombosis, an active policy for prolonged thromboprophylaxis is demanded. Rapid and reliable assays should be developed for diagnosis and anticoagulation monitoring to secure safe management with nonheparins. Semiquantitative testing for on-call hours should be available and later confirmed as clinically needed. Alternative therapeutic options are available, but because their use is infrequent, experienced coagulation treatment centers should provide guidance in the treatment and in laboratory monitoring. Most of the evidence in HIT is grade IC, and thus the best evidence is provided by clinical experience. New anticoagulants and platelet inhibitors may offer future alternatives in the management of HIT, but the current treatment options provide the best experience and benefit. The joint clinical and laboratory guidelines provided in this article along with two practical case scenarios were prepared by a Nordic expert panel. They will be valuable for hematologists and colleagues who do not routinely encounter HIT.

Topics: Aged; Anticoagulants; Arginine; Cardiac Catheterization; Cardiac Surgical Procedures; Chondroitin Sulfates; Dermatan Sulfate; Female; Heparin; Heparin, Low-Molecular-Weight; Heparitin Sulfate; Hirudins; Humans; Male; Peptide Fragments; Pipecolic Acids; Recombinant Proteins; Sulfonamides; Thrombocytopenia; Vascular Surgical Procedures; Vitamin K; Young Adult