Left Foot Unexplained Swelling

Hi:

My dad just had a pulmonary embolism, 2 small clots in the lungs while being on the Phentanyl Pain Patch, about 3 weeks ago.  Now he is on Coumadin 7.5 and 7 on alternate days in the past week although he has been on an uphill dose of Coumadin for about 3 weeks or so.   About 3 days ago his left foot started swelling at the end of the day.  In the morning it appears almost gone, however it is only on the left foot.  The edema or perphaps lymphedema covers the top of the foot and the ankle area about three inches under the calf.  The first day it was red and hot and the most swollen.  Now the redness has dissappeared.  I know this could be a side effect of Coumadin which I perceive as a very dangerous medication with many side effects, including gangrene, other blood clots, renal failure, liver problems, etc.

However, since it is the left foot only, does anyone think this could be related to heart disease or another condition?  He has varicose veins on both feet, but why only the left foot swells up and this is worse in the evening after he's been out and about?  He tries to drink a lot of water. Don't think it would be salt intake as it would be both feet.  He has not had any trauma to the foot.  He also suffers from vascular necrosis on the hips.