I had mitral valve repair surgery in April this year
I would explain as follows:
Welcome on -Ask a Doctor- service!
I understand your concern and would like to explain that considering your previous medical history several underlying issues that should be explored.
First, lower limbs may become swollen in the settings of right heart failure which could be not rarely encountered in a diseased heart valve patient. In this regard a careful physical examination coupled with a resting ECG, chest X ray study, a NT-proBNP test and a cardiac ultrasound would be helpful. If this is the case, diuretic therapy would be established.
Another alternative could be insufficiency of the lower limb veins. A Doppler ultrasound of the lower limb vessels would clarify this issue.
In addition, renal function test should be explored as an impaired renal function may lead to water accumulation within the body and edema.
You need to discuss with your attending doctor on the above mentioned issues,
Hope to have been helpful!
In case of any further questions, feel free to ask me again.