Thanks for your query.
You can definitely proceed for abortion, under proper medical supervision.
After all, you had DVT almost 12 years back, and took blood thinners at that time.
As you mention, you are no longer taking it.
However, still you must consult a cardiologist
prior to your medical / surgical procedure, whichever your gynecologist advises, for special precautions to be taken.
You can go for the abortion ahead with calculated risk, after proper consultation with specialists.
Please do not worry - medical abortion
is quite safe these days, if properly conducted.