<qa>  What is the term for bridging?Patients who undergo mechanical heart valve replacement are usually placed on long-term oral anticoagulation blood thinning medication to prevent blood clots from forming on the mechanical valve. This is started in the hospital with intravenous unfractionated heparin; patients must remain in the hospital while on unfractionated heparin. At the same time, an oral blood thinner is started warfarin. This process is commonly referred to as bridging. Once the warfarin reaches the proper level, the intravenous heparin is stopped. 