Sometimes it can be treated
with an Aspirin a day, but once a clot forms, then there is a need to be on
blood thinners, at least for a while. In my case, being relatively young, and having had many clots, I'm on them permanently
So the reason they treat a DVT with blood thinners, is to prevent the clot from reforming or from moving and ending up in the lungs or heart which would likely be fatal. A clot in the brain is more commonly known as a stroke.