title: Venous limb gangrene during overlapping therapy with warfarin and a direct thrombin inhibitor for immune heparin-induced thrombocytopenia.
abstract: We report two patients with deep-vein thrombosis complicating immune heparin-induced thrombocytopenia who developed venous limb gangrene during overlapping therapy with a direct thrombin inhibitor (lepirudin or argatroban) and warfarin. In both patients, therapy with the direct thrombin inhibitor was interrupted during persisting severe athrombocytopenia while warfarin administration continued. Both patients exhibited the typical feature of a supratherapeutic international normalized ratio (INRs, 5.9 and 7.3) that has been linked previously with warfarin-associated venous limb gangrene. These data suggest that warfarin anticoagulation be postponed in patients with acute heparin-induced thrombocytopenia until substantial recovery of the platelet count has occurred.
authors.affiliation: Department of Pharmaceutical Services, William Beaumont Hospital, Royal Oak, Michigan 48073-6769, USA.
authors.forename: Maureen A
authors.initials: MA
authors.lastname: Smythe
authors.forename: Theodore E
authors.initials: TE
authors.lastname: Warkentin
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Stephens
authors.forename: Dana
authors.initials: D
authors.lastname: Zakalik
authors.forename: Joan C
authors.initials: JC
authors.lastname: Mattson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000671:Amputation, Surgical; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D001120:Arginine / Q000031:analogs & derivatives; D001327:Autoimmune Diseases / Q000139:chemically induced / Q000188:drug therapy* / Q000276:immunology; D002405:Catheterization, Central Venous; D000075202:Contraindications; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D005734:Gangrene; D006493:Heparin / Q000009:adverse effects*; D024764:Hirudin Therapy; D006629:Hirudins / Q000008:administration & dosage / Q000009:adverse effects* / Q000031:analogs & derivatives; D006801:Humans; D019934:International Normalized Ratio; D007866:Leg / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D010875:Pipecolic Acids / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D020151:Protein C Deficiency / Q000139:chemically induced; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D013449:Sulfonamides; D013530:Surgical Wound Infection / Q000188:drug therapy; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000378:metabolism; D013921:Thrombocytopenia / Q000139:chemically induced / Q000188:drug therapy* / Q000276:immunology; D013924:Thrombophlebitis / Q000139:chemically induced*; D014859:Warfarin / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D006629:Hirudins; D010875:Pipecolic Acids; D011994:Recombinant Proteins; D013449:Sulfonamides; D014859:Warfarin; D006493:Heparin; D001120:Arginine; D013917:Thrombin; C031942:argatroban; C083544:lepirudin