Dear friend, Thanks for posting your query on this website. I fully appreciate your concerns. Firstly, there are certain inherent conditions which predispose to recurrent formation of clots in the blood vessels. I presume that these conditions must been excluded. If yes, then warfarin is continued for about 3-6 months, with frequent monitoring of INR so as to maintain it between 2 - 2.5; frequent color Doppler flow study of the affected blood vessel to observe re-formation of clots; bleeding tendencies if any and, liver function tests. The duration of continuing warfarin- as a preventive measure- for 3-6 months, has been recommended on the basis of outcome of several studies. However, in patients who have higher risk of developing recurrent clots in the vessels, warfarin has been advocated to continue for longer period, upto one year or even more. Adequate calcium + Vit D supplements are strongly recommended along with warfarin, as the latter promotes removal of calcium from the bones. I am sure that you will benefit from the advice. Please feel free to revert back to me in case of further clarifications, if any. Have a speedy recovery and a good health. Fond Regards, Dr.(Col) R Karanwal