Why does my doctor have me come off warfarin 5 days before a surgical procedure and take lovenox (enoxaparin) instead?

Because... Your doctor does not want you to bleed during the surgery and in the same time your doctor does not want you to develop another kind of blood clots while you are not taking your warfarin. That is why your doctor wants you to stop the warfarin and bridged you on the Lovenox (enoxaparin) while you are off the warfarin. Please discuss with your doctor for other question.
Bleeding. He does not want you to bleed to death, and he wants to protect you with the Lovenox (enoxaparin) for the peri operative period.
Bridging. Warfarin is very unpredictable in terms of half live. So we switch to a more predicable 1/2 life and therfore be out of your system by procedure time.. Hope this was helpful. Dr d.