The use of direct thrombin inhibitors in cardiovascular surgery in patients with heparin-induced thrombocytopenia.
One of the most important adverse drug reactions that physicians encounter is the life- and limb-threatening prothrombotic syndrome known as heparin-induced thrombocytopenia (HIT). Unfractionated heparin (UFH), administered during cardiopulmonary bypass (CPB), is highly immunogenic. Heparin-dependent antibodies can develop in 25 to 50% of UFH-treated cardiac surgery patients within 5 to 10 days. These antibodies can activate platelets and are considered the causative agents of HIT. HIT is a relatively common complication, occurring in 1 to 3% of cardiovascular surgery patients when UFH administration is continued postoperatively. It is strongly associated with new thromboembolic events leading to limb amputation and death. In acute or recent (< 100 days) HIT, alternative anticoagulatory regimens are needed during CPB surgery for prevention of HIT-related thrombosis. Treatment options for such patients now generally include the use of alternative anticoagulants such as lepirudin, bivalirudin, or danaparoid, as well as a combined treatment with platelet-function inhibitors and heparin. In patients with a history of HIT and no detectable antibodies, heparin is currently the safest approach for high-dose anticoagulation during CPB. Before and after surgery, however, alternative anticoagulants should be used. The risk of clinical HIT after heart surgery could potentially be reduced by using low-molecular-weight heparins for postsurgery anticoagulation.
Institut für Immunologie und Transfusionsmedizin, Ernst-Moritz-Arndt-Universität, Diagnostikzentrum, Greifswald, Germany. greinach@uni-greifswald.de
Andreas
A
Greinacher
D000925:Anticoagulants / Q000009:adverse effects* / Q000627:therapeutic use; D002318:Cardiovascular Diseases / Q000188:drug therapy* / Q000601:surgery*; D002986:Clinical Trials as Topic; D004797:Enzyme-Linked Immunosorbent Assay; D006493:Heparin / Q000009:adverse effects* / Q000276:immunology; D006629:Hirudins / Q000031:analogs & derivatives*; D006801:Humans; D010976:Platelet Count; D011994:Recombinant Proteins / Q000627:therapeutic use; D013917:Thrombin / Q000037:antagonists & inhibitors*; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000175:diagnosis / Q000188:drug therapy*; D013997:Time Factors
D000925:Anticoagulants; D006629:Hirudins; D011994:Recombinant Proteins; D006493:Heparin; D013917:Thrombin; C083544:lepirudin