title: [Use of warfarin and low range INR in the prevention of recurrent venous thrombosis].
abstract: The object of this work was to determine the efficacy of a low range International Normalized Ratio (INR) between 1.5 and 1.9, in preventing recurrent venous thrombosis and the hemorrhagic manifestations that can complicate anticoagulation with warfarin. Thirty nine patients, 10 to 78 years of age were studied between January 2006 and November 2009. All of them had been treated with warfarin, for at least 6 months, due to deep venous thrombosis or pulmonary embolism. The subjects were separated, at random, into two groups. In group A (20 patients), the doses of warfarin were adjusted until the INR was stabilized between 1.5 and 1.9; in group B, the INR was maintained between 2 and 3. The coagulant activities of plasma factors II, VII, IX and X were determined in a week and between the fourth and fifth weeks, after stabilization of the INR. Plasma activities of the coagulation factors assayed were abnormally low in both groups, in the two opportunities they were determined, although significantly lower in group B (p<0.05). No thromboembolic episodes occurred during the study, in any of the patients. One of the patients from group A and four from group B, presented minor hemorrhagic manifestations (p N.S.) The above results suggest that a range on INR lower that 2, could be sufficient to prevent recurrent thrombotic episodes while diminishing the frequency of hemorrhagic complications associated with the use of warfarin. However, it is necessary to continue incorporating more individuals in the study to obtain greater certainty in the analysis of these results.
authors.affiliation: Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Maracaibo, República Bolivariana de Venezuela. jequin@gmail.com
authors.forename: Jesús
authors.initials: J
authors.lastname: Quintero
authors.forename: Enrique
authors.initials: E
authors.lastname: Torres
authors.forename: María
authors.initials: M
authors.lastname: Diez-Ewald
authors.forename: Melvis
authors.initials: M
authors.lastname: Arteaga-Vizcaíno
authors.forename: Gilberto
authors.initials: G
authors.lastname: Vizcaíno
authors.forename: Mario
authors.initials: M
authors.lastname: León
authors.forename: Zulay
authors.initials: Z
authors.lastname: Rodríguez
authors.forename: Nelson
authors.initials: N
authors.lastname: Fernández
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001779:Blood Coagulation Factors / Q000032:analysis; D002648:Child; D004305:Dose-Response Relationship, Drug; D016903:Drug Monitoring; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000097:blood / Q000188:drug therapy*; D012008:Recurrence; D020246:Venous Thrombosis / Q000097:blood / Q000188:drug therapy*; D014859:Warfarin / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D000925:Anticoagulants; D001779:Blood Coagulation Factors; D014859:Warfarin