At a glance
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A Randomized Double-blind Study of 4-weekly Versus 12-weekly Monitoring of Stable Patients on Long-term Anticoagulation With Warfarin
In Brief
A Phase 2 clinical trial evaluating Dosing warfarin every 12 weeks, sham INRs 2 out of 3 times for Atrial Fibrillation and 2 related conditions. Completed, enrolled 250 participants across 1 site.
Detailed Summary
Patients with mechanical heart valve prosthesis or with irregular beat (atrial fibrillation) have a high risk of blood clot formation. Such clots can result in a stroke. The patients are treated with warfarin - a "blood thinner" - to prevent these complications. The treatment has to be monitored with a blood test called Prothrombin time (PT) every 1-4 weeks. The dose of warfarin has to be changed whenever the PT result is outside of the treatment range. If the result is too low there is an increased risk of blood clots. If, instead, the result is too high there is a risk of bleeding. One third of the patients have very stable PT results and hardly ever have to change the dose. The investigators hypothesis is that these patients can go less often, e.g. every 12 weeks, for the blood tests.
Study Details
Timeline
Interventions
Warfarin is dosed according to INR to maintain INR 2.0-3.0 or for mechanical mitral valves or mechanical aortic valves with atrial fibrillation INR 2.5-3.5