What are the causes of a failed fem-pop or any other graft bypass?

Question

(I'm a med student trying to explain it to a patient - in exams!)

Answer 1

The #1 reason is continued smoking.

Others include :

1) stopping anticoagulation or antiplatelet meds

2) a stenosis (narrowing) has developed in the graft

3) the outflow vessels (the arteries downstream from the graft) are naturally small. This causes the blood flow through the graft to slow, making it more likely to clot.

Answer 2

"Sir, if you continue to smoke, the process that caused your artery to become blocked will do the same thing to the new graft, or to other spots along the artery, and all of this that you're going through will have been for nothing.  There is also the chance that clots will form in the graft and block it. "