Question

My mother had bypass surgery some months ago. Now her ankles swell a lot. What causes this? She is on water pills but they don't seem to help.

Answer

When bypass surgery is performed, at least one vein is taken from a leg to act as a new channel for the blood to bypass the blockage in the heart. The piece of vein is transplanted to connect the aorta to the heart, thus bypassing the blockage. Unfortunately, veins are important for drainage in the legs. Therefore, if a vein is taken out, chronic swelling can (although not always) occur in the leg. (You don't say if you mother had veins taken from both legs, which is sometimes necessary).

We call this a form of dependent edema (gravity dependent). Such swelling in the leg can eventually go away, but I tell folks to give it a year before saying that this is how it is always going to be. It is not an issue of too much fluid in the body, but rather a drainage problem. Keeping the leg up when sitting, or using support stockings, can help. Sometimes diuretics (water pills) can help, but, again, this is a drainage problem and not fluid overload.