How much time should one take warfarin after aortic valve replacement tissue valve?

Check with your doc: If you have your aortic valve replaced with a tissue valve, some surgeons do not recommend warfarin at all, others may suggest you take a blood thinner for a short while e.g. 1-3 months. If you have any other problems such as an irregular heart beat like atrial fibrillation, you may have other reasons that you would need warfarin. It would be best to check with your doctor.