Management of coumarin-associated coagulopathy in the non-bleeding patient: a systematic review.
OBJECTIVE
Excessive anticoagulation is a frequent complication of anticoagulant therapy. The risk of hemorrhage approximately doubles for each one point increase in the International Normalized Ratio (INR) above 3.0. Reducing a prolonged INR to within the desired therapeutic range requires that oral anticoagulants be withheld. In addition, vitamin K may be administered. Since this latter treatment can produce rapid reductions in the INR, it must be carefully tailored to meet individual needs, balancing the risk of bleeding against the potential risk of causing thromboembolism.


METHODS
To review available literature on the management of coumarin-associated coagulopathy in asymptomatic patients, a Medline search was carried out and papers published in English from 1966 and 2003 were identified. All available information on the management of asymptomatic patients presenting with coumarin-associated coagulopathy was analyzed.


RESULTS
Following the results of clinical studies that only used an elevated INR as a surrogate end-point for the risk of bleeding, low dose oral vitamin K appears as the preferable strategy for rapidly restoring therapeutic INR levels in asymptomatic patients who present with an excessively prolonged INR due to warfarin therapy. For the treatment of patients with asymptomatic acenocoumarol-induced coagulopathy, vitamin K does not add any benefit to the strategy of simply withholding oral anticoagulant treatment.


CONCLUSIONS
Large randomized trials using clinical end-points are now required to provide evidence-based treatment recommendations for patients with coumarin-associated coagulopathy.
Dentali
Francesco
F
Internal Medicine, University of Insubria, Varese, Italy.
Ageno
Walter
W
D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects*; D000933:Antifibrinolytic Agents / Q000008:administration & dosage; D001778:Blood Coagulation Disorders / Q000139:chemically induced* / Q000188:drug therapy / Q000628:therapy*; D003365:Costs and Cost Analysis; D003374:Coumarins / Q000008:administration & dosage / Q000009:adverse effects*; D006470:Hemorrhage / Q000517:prevention & control; D006801:Humans; D019934:International Normalized Ratio / Q000592:standards; D012307:Risk Factors; D014812:Vitamin K / Q000008:administration & dosage; D014859:Warfarin / Q000008:administration & dosage / Q000009:adverse effects; D028761:Withholding Treatment
D000925:Anticoagulants; D000933:Antifibrinolytic Agents; D003374:Coumarins; D014812:Vitamin K; D014859:Warfarin; C030123:coumarin