Any ideas if i can have gastric bypass surgery while on coumadin (warfarin)?

Stop before surgery: Coumadin (warfarin) should be discontinued for 4-5 days before a surgical procedure to avoid excessive surgical bleeding. It takes that long for the effects to wear off. For patients on coumadin (warfarin) because of a mechanical heart valve, some form of heparin is sometimes prescribed for a day or two before the surgery and then stopped (heparin is stopped closer to surgery because its effects don't last as long.)