Coumadin prior to major surgery, your experience?

[miloisstinky]

Im having a frustrating time finding specific information, so I thought I would resource CRNA's for experience with this situation.

Major abdominal surgery (potential 1500ml blood loss), the patient is s/p valve repair >15 years ago on coumadin. He has been switched to LMWH, most recent labs 4 days prior to this surgery PT-24.9 and INR-2.32.

What is the lowest acceptable INR you have seen that proceeds with surgery? Can I expect his labs to normalize 4 days later after these results? Is it easy enough to just "reverse" the coumadin with Vit. K/FFP's prior to surgery?

[athomas91]

you would need to give platelets for immediate reversal/platelet function... vit k will work but isn't effective for 24 hours..

usually these people are hospitalized and started on heparin 4 days prior to surg.. heparin d/ced approx 6-8 hrs prior to surg...

[piper77]

Yep, I agree with athomas; I would feel much more comfortable with an INR in the neighborhood of 1.5. I dislike the LMWH for this very reason. Post op is going to suck as well as intraop. Makes more sense to hospitalize, heparinize...can turn it on and off as you need; then re-establish a regimen for home. Getting a cardiac consult because of those valves? Would be a good discussion with the cardiologist.

[underdog]

I was waiting for other posts on this topic, but thus far there has been only the two, so I figured that I would chime in. First of all, I agree with a couple of athomas' points that Vit K would help, but not until later down the road. I also like the idea of the IV heparin "bridge" for this patient after D/Cing the Coumadin. Furthermore, I agree with piper that I would like to see the INR at least 1.5 if not lower before proceeding with surgery.

I do however have a differing view of trying to get the elevated PT and INR back to acceptable levels. The PT/INR are measures of the extrinsic (& common) coagulation pathway, and are affected by Coumadin and not heparin. Heparin affects the intrinsic (& common) pathway and is monitored with the lab value PTT. I believe that the reason for the elevated PT/INR was that the labs were drawn too close to the cessation of the Coumadin. I would re-draw these pre-op and expect to have values closer to normal after the four days the OP mentioned had passed. If the labs still came back with an elevated PT/INR, this would show lingering effects of the Coumadin and not LMWH. Coumadin works by binding to Vit K receptors in the liver and thus competitively inhibiting Vit K and the production of Vit K dependent clotting factors (II, VII, IX, X).

Factor II (Thrombin) is inhibited by Coumadin as stated above. Thrombin is essential in activating platelets by combining with a thrombin receptor on the surface of the platelet to release mediators such as thromboxane and ADP, both of which promote platelet aggregation. Hence, without Factor II which is inhibited by Coumadin, you could give all the platelets you wanted but they would not be activated or be able to aggregate because of the lack of thrombin. Therefore the correct way to normalize the elevated PT/INR for surgery would be to give FFP which contains the necessary clotting factors such as thrombin to be able to initiate the process of platelet activation/aggregation.

[athomas91]

underdog is absolutely right... i was thinking ASA and board review.... :)

FFP is used for urgent reversal of warfarin Tx.

[Tranman]

underdog, you're good dude. we're not worthy!!

[underdog]

Thanks Tranman....for some strange reason the coagulation pathway is one of the FEW things that has stuck in my head since taking boards last year. It is amazing how fast some of that info diappears.