Supratherapeutic INR

Q: 52 years old patient with active colon cancer and atrial fibrillation is admitted from ER to ICU with INR of 9 but no visible clinical bleed. The patient was sent to the ER after his scheduled INR blood draw at an outpatient clinic. Patient's active underlying cancer will ____________ the recovery of INR to therapeutic level? (Select one)

A) expedites

B) slows

Answer: B

Patients with supra-therapeutic levels between INR 4.5 to 10 without visible clinical bleeding usually do not require vitamin K administration. Holding of warfarin is usually sufficient. Said that at least one retrospective review shows that few conditions may slow this recovery, and there should be a low threshold for administration of Vitamin K in these patients' population.

• Older age - described as odds ratio [OR] 1.2 per decade of life
• Higher index INR - described as OR 1.25 per unit of elevation
• Lower warfarin maintenance dose described as OR 0.87 per 10 mg increase in total weekly dose
• Decompensated heart failure (OR 2.79)
• Active cancer (OR 2.48)
• Lack of rapid access to medical care

#hematology

Reference:

Hylek EM, Regan S, Go AS, et al. Clinical predictors of prolonged delay in return of the international normalized ratio to within the therapeutic range after excessive anticoagulation with warfarin. Ann Intern Med 2001; 135:393.