Poor correlation of supratherapeutic international normalised ratio and vitamin K-dependent procoagulant factor levels during warfarin therapy

Ravindra Sarode, Ajay Rawal, Ray Lee, Yu Min Shen, Eugene P. Frenkel

Research output: Contribution to journalArticle

33 Scopus citations

Abstract

Patients with a supratherapeutic international normalised ratio (ST-INR) are at risk for bleeding. ST-INR is corrected by withholding warfarin therapy and often by supplementing vitamin K or providing vitamin K-dependent factors; the exact therapeutic decision is based on the extent of the prolonged INR. Currently, ST-INRs are frequently observed in clinical practice due to the use of sensitive recombinant tissue thromboplastin reagents and automation. However, there are scant data correlating an ST-INR with various vitamin K-dependent factors. This prospective cohort study, set in a large tertiary care teaching hospital for the University of Texas Southwestern Medical Center at Dallas, defined the relationship between ST-INR (>5·0) and measured vitamin K-dependent procoagulant factors. Prothrombin time, INR and vitamin K-dependent factors II, VII, IX and X were measured in 78 patients with an INR > 5·0 (ST-INR) who were on warfarin therapy for more than 2 months. There was no significant relationship between the ST-INR and levels of important vitamin K-dependent factors II and X. These data support the recent guidelines that the management of an INR > 5·0 should be driven by the clinical determinants rather than specific INR values per se.

Original languageEnglish (US)
Pages (from-to)604-607
Number of pages4
JournalBritish Journal of Haematology
Volume132
Issue number5
DOIs
StatePublished - Mar 1 2006

Keywords

  • International normalised ratio (INR)
  • Vitamin K therapy
  • Vitamin K-dependent factors
  • Warfarin

ASJC Scopus subject areas

  • Hematology

Fingerprint Dive into the research topics of 'Poor correlation of supratherapeutic international normalised ratio and vitamin K-dependent procoagulant factor levels during warfarin therapy'. Together they form a unique fingerprint.

  • Cite this