Study objective: To determine the outcome of over-anticoagulated patients who were treated with vitamin K and those who were treated conservatively by holding doses and increasing monitoring frequency. A secondary objective was to compare conservative management with American College of Chest Physicians (ACCP) treatment guidelines when followed.
Design: Retrospective chart review of all patients with international normalized ratios (INRs) of 6 or greater and concurrently receiving warfarin between November 1993 and February 1994.
Setting: A Veterans Affairs Medical Center providing inpatient and outpatient care. Patients receiving warfarin are managed by an established anticoagulation clinic.
Patients: Fifty-one consecutive patients receiving warfarin who had an INR of 6 or greater were reviewed.
Interventions: Data collection included INR, risks for bleeding, indication for anticoagulation, interventions, and patient outcomes.
Results: INRs ranged from 6.1 to 81.8. Forty-eight patients (94%) did not receive vitamin K; they were treated by withholding doses and increasing monitoring frequency. One developed minor bleeding. Three patients (6%) received vitamin K. Two of these patients died of unrelated problems. The third patient required 47 days of heparin therapy prior to achieving therapeutic oral anticoagulation.
Conclusion: This trial showed that conservative treatment of nonbleeding overanticoagulated patients is safe. A prospective trial comparing the ACCP guidelines with a conservative approach is needed.