G
Guest
Over the last week I have been at meeting of anticoagulation specialists. We had two speakers who debated warfarin bridging. The worst complication for those who are bridged is bleeding. The time of most danger from bleeding is right after the surgery.
#1 said to tailor the bridging to the patient. If you have a low-risk patient (atrial fibrillation) undergoing a procedure with a high risk of bleeding like bowel cancer surgery then it might be best not to bridge. If you have a high-risk of clotting patient (mechanical mitral valve) having a low-risk of bleeding procedure such as arthroscopic surgery then it is probably best to bridge. For all the other classifications like
low risk of clotting person getting low risk of bleeding
high risk of clotting person getting high risk of bleeding
the choice can be made by rolling dice (we were in Las Vegas).
#2 said to bridge everyone but to modify the dosing especially if there is a high risk of bleeding from the procedure.
Procedure - 5 days stop warfarin
Procedure - 4 days start Lovenox 1 mg/kg every 12 hours
Procedure - 3 days same as day 4
Procedure - 2 days same as day 4
Procedure - 1 day give the morning Lovenox but not the evening
Day of Procedure - no anticoagulation
Procedure + 1 day give Lovenox 40 mg X 1 dose & restart warfarin
Procedure + 2 days same as day 1
Procedure + 3 days same as day 1
Procedure + 4 days change Lovenox to 1 mg/kg every 12 hours and continue warfarin. Keep doing this until the INR is in the desired range for two days and then stop Lovenox.
If the person has poor kidney function, the Lovenox would not be raised on procedure + 4 days because of the risk of the Lovenox accumulating in the body and causing bleeding.
They both agreed that Lovenox has not been approved for this use. There have been lots of studies that show that this is opretty safe and effective, but none that were definitive for the FDA to rule that it is a safe and effective procedure. There probably never will be any definitive studies because Lovenox has such a large market share that their only risk is losing that share of the studies turned out poorly. So money will likely not ever be available for the studies.
They also agreed that no study has ever been done with IV heparin drip for people with mechanical heart valves. Therefore, there is no evidence whether it is safe or effective.
#1 said to tailor the bridging to the patient. If you have a low-risk patient (atrial fibrillation) undergoing a procedure with a high risk of bleeding like bowel cancer surgery then it might be best not to bridge. If you have a high-risk of clotting patient (mechanical mitral valve) having a low-risk of bleeding procedure such as arthroscopic surgery then it is probably best to bridge. For all the other classifications like
low risk of clotting person getting low risk of bleeding
high risk of clotting person getting high risk of bleeding
the choice can be made by rolling dice (we were in Las Vegas).
#2 said to bridge everyone but to modify the dosing especially if there is a high risk of bleeding from the procedure.
Procedure - 5 days stop warfarin
Procedure - 4 days start Lovenox 1 mg/kg every 12 hours
Procedure - 3 days same as day 4
Procedure - 2 days same as day 4
Procedure - 1 day give the morning Lovenox but not the evening
Day of Procedure - no anticoagulation
Procedure + 1 day give Lovenox 40 mg X 1 dose & restart warfarin
Procedure + 2 days same as day 1
Procedure + 3 days same as day 1
Procedure + 4 days change Lovenox to 1 mg/kg every 12 hours and continue warfarin. Keep doing this until the INR is in the desired range for two days and then stop Lovenox.
If the person has poor kidney function, the Lovenox would not be raised on procedure + 4 days because of the risk of the Lovenox accumulating in the body and causing bleeding.
They both agreed that Lovenox has not been approved for this use. There have been lots of studies that show that this is opretty safe and effective, but none that were definitive for the FDA to rule that it is a safe and effective procedure. There probably never will be any definitive studies because Lovenox has such a large market share that their only risk is losing that share of the studies turned out poorly. So money will likely not ever be available for the studies.
They also agreed that no study has ever been done with IV heparin drip for people with mechanical heart valves. Therefore, there is no evidence whether it is safe or effective.