Supratherapeutic INR (>5.0) showed no significant relationship with levels of important vitamin K-dependent factors II and X in patients on chronic warfarin therapy.
Cohort (n=78)
No
Does a supratherapeutic INR (>5.0) correlate with levels of vitamin K-dependent procoagulant factors in patients on long-term warfarin therapy?
Supratherapeutic INR values (>5.0) do not significantly correlate with levels of vitamin K-dependent factors II and X, supporting guideline recommendations to base management on clinical determinants rather than specific INR values.
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.
Sarode et al. (Wed,) conducted a cohort in Supratherapeutic international normalised ratio (ST-INR) during warfarin therapy (n=78). Supratherapeutic INR (>5.0) was evaluated on Relationship between ST-INR (>5.0) and measured vitamin K-dependent procoagulant factors (II, VII, IX and X). Supratherapeutic INR (>5.0) showed no significant relationship with levels of important vitamin K-dependent factors II and X in patients on chronic warfarin therapy.