title: Hypercoagulable state and thromboembolism following warfarin withdrawal in post-myocardial-infarction patients.
abstract: Nine out of 47 (19%) patients on chronic anticoagulation with warfarin, as secondary prophylaxis after myocardial infarction, initially treated with streptokinase, had thromboembolic complications within 4 weeks after sudden (7/25) or gradual (2/22:NS) warfarin withdrawal. The biochemical effects of warfarin withdrawal were repeatedly studied in 20 of the patients during the first 14 days following drug cessation. During the first 4 days, the levels of coagulation factors VII and IX increased more rapidly than proteins C and S. Thus, a gap was created between the factors provoking and inhibiting the coagulation process. Furthermore, plasma concentrations of fibrinopeptide A (FPA) increased, reflecting activation of the coagulation system. These laboratory findings suggest that withdrawal of warfarin creates a transient hypercoagulable state, imposing a risk of thromboembolic events in patients given anticoagulant treatment as secondary prophylaxis following myocardial infarction.
authors.affiliation: Department of Cardiology, Karolinska Hospital, Stockholm, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Grip
authors.forename: M
authors.initials: M
authors.lastname: Blombäck
authors.forename: S
authors.initials: S
authors.lastname: Schulman
mesh_terms: D000328:Adult; D000368:Aged; D000789:Angina, Unstable / Q000097:blood / Q000209:etiology; D001778:Blood Coagulation Disorders / Q000097:blood / Q000209:etiology*; D001779:Blood Coagulation Factors / Q000032:analysis; D002561:Cerebrovascular Disorders / Q000097:blood / Q000209:etiology; D004359:Drug Therapy, Combination; D005260:Female; D006493:Heparin / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy*; D016491:Peripheral Vascular Diseases / Q000097:blood / Q000209:etiology; D013300:Streptokinase / Q000627:therapeutic use; D013923:Thromboembolism / Q000097:blood / Q000209:etiology* / Q000517:prevention & control; D016896:Treatment Outcome; D014812:Vitamin K; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D001779:Blood Coagulation Factors; D014812:Vitamin K; D014859:Warfarin; D006493:Heparin; D013300:Streptokinase