Chronic swelling your legs can have many causes, but it sounds like you have been evaluated for this problem already by both your primary doctor and the vascular doctor. My
guess is that you have a condition known as venous insufficiency, which is caused by the weakening of the veins in your legs. This is a quite common problem that I see alot in my practice, as it tends to worsen as people grow older.
I am glad that the leg wraps helped you, as compression of the leg is one of the best ways to get rid of the edema. Since the wraps have stopped, I am hoping that you are wearing your compression stockings as you should (on as soon as you get up in the morning, off when you get into bed each night) and that you elevate your legs during the day when you can. If you are doing these things already and you are still getting edema, I would talk to your primary care doctor about the possibility that you need to have the leg wraps again. This is important for you, since you are diabetic, and it may help prevent further leg infections (cellulitis). It also may keep you from developing a complication called venous ulcers, which are wounds that can occur on your legs if this condition becomes severe.