LMWH "rebridging"...

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WVUPharm2007

WVUPharm2007

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Come ye students...and practitioners...and whomever...

So lets say there is a patient. Admitted to hospital. Hx of a-fib, DM, HTN, 80 y/o. They are admitted with something else....oh, let's say cellulitis. **** it, doesn't matter.

Now, let's say they are on Coumadin due to the a-fib. Plus, they aren't really mobile. The routine coag panal shows an INR of 1.4. Obviously, you want them to be sufficiently anticoagulated and you'd like that to be >2...so ignoring everything else you'd do for the patient and concentrating on their anticoag regimen....

Which of these do you do:

1) Add no immediate LMWH and increase dose of warfarin until the INR is ok.
2) Add 40mg SQ Lovenox a day while patient is receiving increased warfarin doses until INR is fine.
3) Add 1mg/kg Sq Lovenox q12h with increased warfarin dose until the INR is fine.

...and why?
 
I'd probably play by the book and go with #3 and bridge, stay with their normal regimen of warfarin for a few days (they probably just missed some doses) and then increase if needed.
 
#2, Risk factors for DVT include age>75, DM, HTN, Afib with subtherapeutic INR, and immobility. I don't think it's worth the risk to just assume the pt missed a few doses and hope the INR will become therapeutic in a few days.
 
That is a good question because it comes up a lot.

If the pt was an outpt and had an INR of 1.4, would they start LMWH? Likely not. They would either give him a load +/- increasing the dose based on his history. But since he is admitted, a lot of times they feel obligated to bridge. If the pt was MVR or some other high risk indication, I would feel more obligated to bridge. With an indication of a-fib, generally we are less concerned about getting the patient therapeutic quickly. This is our general thought process where I work. I would be curious to see what other practioners do at their institutions. I think either #1 or #3 are correct. I feel if the patient is on warfarin, you either bridge them or not...there isn't much evidence of using prophylactic dosing with warfarin.
 
If you're really worried about the AFib...then start her on Heparin Drip... 75u/kg Loading (max 5000) with 13u/kg/hr and titrate.. as if she had ACS. Definitely not #2 because that's just VTE prophylaxis. #3 is ok...but now you seriously risk bleeding...do heparin...you can turn it on and off in a hearbeat (no pun) with Protamine standing by.
 
WVUPharm2007 said:
Come ye students...and practitioners...and whomever...

So lets say there is a patient. Admitted to hospital. Hx of a-fib, DM, HTN, 80 y/o. They are admitted with something else....oh, let's say cellulitis. **** it, doesn't matter.

Now, let's say they are on Coumadin due to the a-fib. Plus, they aren't really mobile. The routine coag panal shows an INR of 1.4. Obviously, you want them to be sufficiently anticoagulated and you'd like that to be >2...so ignoring everything else you'd do for the patient and concentrating on their anticoag regimen....

Which of these do you do:

1) Add no immediate LMWH and increase dose of warfarin until the INR is ok.
2) Add 40mg SQ Lovenox a day while patient is receiving increased warfarin doses until INR is fine.
3) Add 1mg/kg Sq Lovenox q12h with increased warfarin dose until the INR is fine.

...and why?
Click to expand...
Give em Aspirin
 
See, this is a question that has no definite answer from objective data. That I know of, anyway. If I was a pharmacy resident, I'd be all about doing a retrospective study on this ****...pour through mad data...

...but what would Mike do?

If the patient is compliant with the drug, I would do what Z suggests...just increase dose and monitor INR. Though what would be the legal implications of a low INR with a patient experiencing an event prevented by warfarin? I know for a fact some practitioners add Lovenox from a defensive medicine, CYA, approach. With the sharks out there...perhaps that's not too crazy.

...but what about compliance. Let's say the patient's compliance has been ****. If that's the case, would heparin/LMWH therapy upon warfarin reinitialization be warranted? I would say unequivocally so. If old Mrs. Weinerschneikel has taken it in a month, I start 1mg/kg q12h.

So I think it depends on many things...obviously indication...the actual INR...and the status of the Protein C/S homeostasis...

If any of you guys know of a study that looks at all of this and draws any sort of conclusion, I'd love to see it...

Anyway...this came up at work...been thinking about it...
 
WVUPharm2007 said:
See, this is a question that has no definite answer from objective data. That I know of, anyway. If I was a pharmacy resident, I'd be all about doing a retrospective study on this ****...pour through mad data...

...but what would Mike do?

If the patient is compliant with the drug, I would do what Z suggests...just increase dose and monitor INR. Though what would be the legal implications of a low INR with a patient experiencing an event prevented by warfarin? I know for a fact some practitioners add Lovenox from a defensive medicine, CYA, approach. With the sharks out there...perhaps that's not too crazy.

...but what about compliance. Let's say the patient's compliance has been ****. If that's the case, would heparin/LMWH therapy upon warfarin reinitialization be warranted? I would say unequivocally so. If old Mrs. Weinerschneikel has taken it in a month, I start 1mg/kg q12h.

So I think it depends on many things...obviously indication...the actual INR...and the status of the Protein C/S homeostasis...

If any of you guys know of a study that looks at all of this and draws any sort of conclusion, I'd love to see it...

Anyway...this came up at work...been thinking about it...
Click to expand...


Read the Chest Guideline.
 
WVUPharm2007 said:
If I was a pharmacy resident, I'd be all about doing a retrospective study on this ****...pour through mad data...
Click to expand...

And if you were a pharmacy resident, you'd be doing a retrospective study on this **** and present it important people..and do other cool things.:meanie:
 
rphello said:
#2, Risk factors for DVT include ... Afib with subtherapeutic INR,
Click to expand...

Not sure that makes physiologic sense. Usually with afib we think of stroke, because the clot would have to travel through the capillaries to get into the vein to cause the DVT.

She/he is certainly a candidate for warfarin, her CHAD score is >2.
Are we starting antibiotics for this cellulitis? (I know you said answer in a bubble, but i have to think about the whole patient b/c it's all inter-related.) This patient is probably fairly susceptible to his INR jumping up if antibiotics are started.
that being said, and out of your 3 choices I'd pick #3. In real life I'd probably do 2 things. I'd make sure his/her crcl is at least 30ml/min and ideally at least 50. And if it is ok, I'd probably do 1.5mg/kg q24 (unless the patient is obese, then i'd stick with 1mg/kg q12h)
 
steph pharmD said:
Not sure that makes physiologic sense. Usually with afib we think of stroke, because the clot would have to travel through the capillaries to get into the vein to cause the DVT.

She/he is certainly a candidate for warfarin, her CHAD score is >2.
Are we starting antibiotics for this cellulitis? (I know you said answer in a bubble, but i have to think about the whole patient b/c it's all inter-related.) This patient is probably fairly susceptible to his INR jumping up if antibiotics are started.
that being said, and out of your 3 choices I'd pick #3. In real life I'd probably do 2 things. I'd make sure his/her crcl is at least 30ml/min and ideally at least 50. And if it is ok, I'd probably do 1.5mg/kg q24 (unless the patient is obese, then i'd stick with 1mg/kg q12h)
Click to expand...

I was thinking more Cardioembolic stroke than DVT with a-fib. Though with DM, cellulitis, immobility, and A-fib, I'd probably go with UF as well. Cheap, quick, reversible. As for guidelines, I'd have to search through notes for them. #3 rings a bell, but hey, that's what I get for being a non-hospital intern/student.
 
steph pharmD said:
Not sure that makes physiologic sense. Usually with afib we think of stroke, because the clot would have to travel through the capillaries to get into the vein to cause the DVT.
Click to expand...

You're right, when I think of any thromboembolism, then DVT comes to mind. I know it's not technically correct. Immobility could lead to DVT, which is what I was concerned with. Not all afib patients are even on anticoagulants, correct? I guess I overreact when I hear immobility with all of the other risk factors, but lovenox 40mg qd is indicated for acutely ill medical patients.
 
rphello said:
Not all afib patients are even on anticoagulants, correct? I guess I overreact when I hear immobility with all of the other risk factors, but lovenox 40mg qd is indicated for acutely ill medical patients.
Click to expand...


For me, when I have a patient with a fib, I assess the pharmacological stroke reduction necessity based upon the CHADS2 score.
CHADS2 is: CHF (impaired LV function), HTN (>160mmHg), Age (>75), DM, and previous cerebral ischemia (ie. stroke or TIA)
Every "thing" counts as 1 point, except previous Stroke or TIA which counts as 2.
score of zero = aspirin 75 - 325mg/day is sufficient for stroke prophylaxis.
score of one = aspirin 75 - 325mg/day or warfarin (INR 2 - 3)
score of two or greater = warfarin (INR 2 - 3)
Reference: http://chestjournal.chestpubs.org/content/133/6_suppl/546S.long

Also, in acutely ill medical patients, say with pneumonia, we generally use UFH SQ unless they are at higher risk of thrombosis (say from trauma or knee surgery).
 
WVUPharm2007 said:
Come ye students...and practitioners...and whomever...

So lets say there is a patient. Admitted to hospital. Hx of a-fib, DM, HTN, 80 y/o. They are admitted with something else....oh, let's say cellulitis. **** it, doesn't matter.

Now, let's say they are on Coumadin due to the a-fib. Plus, they aren't really mobile. The routine coag panal shows an INR of 1.4. Obviously, you want them to be sufficiently anticoagulated and you'd like that to be >2...so ignoring everything else you'd do for the patient and concentrating on their anticoag regimen....

Which of these do you do:

1) Add no immediate LMWH and increase dose of warfarin until the INR is ok.
2) Add 40mg SQ Lovenox a day while patient is receiving increased warfarin doses until INR is fine.
3) Add 1mg/kg Sq Lovenox q12h with increased warfarin dose until the INR is fine.

...and why?
Click to expand...

Wow, you went from apathetic pharmacy student to caring motivated hospital pharmacist. This is a post I would expect from the teacher's pet, join every organization straight A pharmacy student. Talk about 180. Your now less interesting. :meanie:
 
We need to understand the pathophysiology of A-Fib-thromboemobolic event vs. DVT-PE prophylaxis vs. DVT-PE treatment and pharmacological interventions involved with all three.

Don't confuse VTE prophylaxis for medical/surgical patients with need for anticoagulation in A-Fib.

Your typical Lovenox 40mg SQ daily or Lovenox 30mg SQ q12h is prophylaxis for DVT in patients with risk factors such as post op orthopedic surgery or immobility. If DVT does occur, the clot can travel to the lungs and cause Pulmonary Embolism.

For treatment of DVT/PE, typically Enoxaparin 1mg/kg SQ q12h or Dalteparin 100IU/kg SQ Q12h or 18,000 IU or Heparin Infusion with loading dose of 80u/kg with 18u/kg/hr then titrate.

A-Fib is a different story. The clot in Left Atrium travels to the brain which can lead to stroke. A-Fib patient regardless of anticoagulated or not can have clots in LA.. therefore, prophylaxis dosing of LMWH or Heparin is not adequate. Especially if patient is scheduled for Cardioversion, it's important for the patient be properly anticoagulated before we shock the heck out the patient only to have a clot dislodge from the heart and end up in the brain.

Understand physiology, pathology, and pharmacotherapy.
 
I'd probably go with #1. Loading up an afib patient with LMWH and warfarin seems like overkill. They'd probably been on warfarin for a while and the chances of them having a clot waiting to break off would probably be pretty small I'd also call the dr and see if they were stable and within range previously. You told us to ignore they reason for admission but what if whatever it is can decrease INR and once its under control, INR rises back to normal.

Ugh, wafarin sucks, D/C it and go with LWMH 1mg/kg q12 and let the PCP titrate back up
 
museabuse said:
Wow, you went from apathetic pharmacy student to caring motivated hospital pharmacist. This is a post I would expect from the teacher's pet, join every organization straight A pharmacy student. Talk about 180. Your now less interesting. :meanie:
Click to expand...


...this isn't teacher's pet question and answer ****. There is no sterile environment and pretentious idgits running around demanding to be addressed as Doctor making you do case workups in lab. I really want to know what other people think the standard should be...because I have real people at my real job whose risk for real morbidity is something I would like to really lower...
 
npage148 said:
Ugh, wafarin sucks, D/C it and go with LWMH 1mg/kg q12 and let the PCP titrate back up
Click to expand...

A patient that has reverted back to intrinsic vit k cycling levels pre-warfarin needs to be put on treatment lovenox until inr is in range. Warfarin has an initial prothrombic mechanism due to its side dish inhibition of protein c and s...so...yeah...the pcp would prolly be pissed off atcha...
 
StaviZFingerZ said:
We need to understand the pathophysiology of A-Fib-thromboemobolic event vs. DVT-PE prophylaxis vs. DVT-PE treatment and pharmacological interventions involved with all three.

Don't confuse VTE prophylaxis for medical/surgical patients with need for anticoagulation in A-Fib.

Your typical Lovenox 40mg SQ daily or Lovenox 30mg SQ q12h is prophylaxis for DVT in patients with risk factors such as post op orthopedic surgery or immobility. If DVT does occur, the clot can travel to the lungs and cause Pulmonary Embolism.

For treatment of DVT/PE, typically Enoxaparin 1mg/kg SQ q12h or Dalteparin 100IU/kg SQ Q12h or 18,000 IU or Heparin Infusion with loading dose of 80u/kg with 18u/kg/hr then titrate.

A-Fib is a different story. The clot in Left Atrium travels to the brain which can lead to stroke. A-Fib patient regardless of anticoagulated or not can have clots in LA.. therefore, prophylaxis dosing of LMWH or Heparin is not adequate. Especially if patient is scheduled for Cardioversion, it's important for the patient be properly anticoagulated before we shock the heck out the patient only to have a clot dislodge from the heart and end up in the brain.

Understand physiology, pathology, and pharmacotherapy.
Click to expand...

The lovenox isn't my worry, it's more on the warfarin. The lovenox is the safety valve in this case. The question is, should we turn on the safety valve...not how the safety valve works...

I'm just saying that there might be some cases where starting tx doses of lmwh might be justified in patients coming in that are supposed to be on warfarin whose inr isn't where it should be...

...or maybe I'm crazy...

...hence, I'd like a discussion to see where everyone is at on this ****...

/..and, no, this isn't covered in the guidelines...I read 'em again...
 
WVUPharm2007 said:
The lovenox isn't my worry, it's more on the warfarin. The lovenox is the safety valve in this case. The question is, should we turn on the safety valve...not how the safety valve works...

I'm just saying that there might be some cases where starting tx doses of lmwh might be justified in patients coming in that are supposed to be on warfarin whose inr isn't where it should be...
Click to expand...

then why even bring up choice #2?
 
StaviZFingerZ said:
then why even bring up choice #2?
Click to expand...
Maybe they think afib isn't the primary concern and the dvt risk from immobility is more concerning. We understand the pathophysiology, pharmacology and whatever other -ology. Like WVU said, I've seen cardiologists choose #2 in similar cases.
 
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rphello said:
Maybe they think afib isn't the primary concern and the dvt risk from immobility is more concerning.
Click to expand...

Get real. You actually believe DVT prophylaxis is more important than stroke prevention? Why not anticoagulate for A-fib so DVT prophylaxis is taken care of at the same time? Why would thromboembolism in deep vein more of a concern than thromboembolism in the brain?

We understand the pathophysiology, pharmacology and whatever other -ology. Like WVU said, I've seen cardiologists choose #2 in similar cases.
Click to expand...

So, you've seen cardiologists do it. Do you know why they do it?
Cardiologists are most likely choosing lower dose Lovenox not because of DVT prophylaxis. It's because the patient is already anticoagulated with warfarin albeit not therapeutic due to Low INR. Therefore Lovenox is to augment the warfarin.

Why so defensive about knowing all the ology?
 
Last edited:
StaviZFingerZ said:
So, you've seen cardiologists do it. Do you know why they do it?
Cardiologists are most likely choosing lower dose Lovenox not because of DVT prophylaxis. It's because the patient is already anticoagulated with warfarin albeit not therapeutic due to Low INR. Therefore Lovenox is to augment the warfarin.
Click to expand...

That don't make no sense, cousin. Is 40mg enough to sufficiently "augment" subtherapeutic INR for stroke prevention? We's startin' to talk some hillbilly rigged medicine here ain't'n we?
 
WVUPharm2007 said:
That don't make no sense, cousin. Is 40mg enough to sufficiently "augment" subtherapeutic INR for stroke prevention? We's startin' to talk some hillbilly rigged medicine here ain't'n we?
Click to expand...

Of course it don't...I never said it was correct...
 
I still stand by full dose Heparin infusion or Enoxaparin 1mg/kg q12h until INR > 2.
 
So I guess my first response of "#1 Stupid" is the best response.
 
Pharmacy intern here so my info may be WRONG (And I'm ok with that because we're supposed to not know anything.)

Anyways, I've been dosing anti-coag for pt's with a-fib past week per hospital protocol.

A-fib INR goal is 2-3.

I always thought bridging was only used for patients who were on warfarin and need to stay off it for a scheduled surgery. Takes 3-5 days for warfarin effects to wear off so e need to bridge it with a LMWH (since that can be d/c'd 12-24 hr before surgery). Then start warfarin after surgery and rebridge the other way with LMWH (sorry for stating the obvious).

Based on the given situation, I'd just go with #1. I'd monitor INR closely and for day #1 in hospital, I'd see what his average warfarin dose was prior to admittance and probably hit them with a higher dose. Also depending on the kind of ABX used for cellulitis, I'd make note of the possible drug interaction when checking INR levels.

I mean, 1.4 means he was sub-therapeutic for his a-fib prior to admission. If we was alternating between 5mg 3 times a week and 7.5mg the other 4 days, I'd start him off with the 7.5 mg and check INR in the am. And whatever the INR tells me the next morning will dictate how aggressive I will be with his next dose.

I'd also be more focused on the a-fib over DVT/PE prophy. Unfortunately, DVT/PE prophy is sometimes overlooked. 🙁



EDIT: if there is a guidline or a study stating we should add on LWMH bridging as a "safety valve" for sub-therapuetic pt's who are already on and compliant on warfarin, please let me know.
 
StaviZFingerZ said:
Get real. You actually believe DVT prophylaxis is more important than stroke prevention? Why not anticoagulate for A-fib so DVT prophylaxis is taken care of at the same time?
Click to expand...
All of the risks associated with treatment dose Lovenox come to mind. Sure, that makes sense, but what if it's too much?

So, you've seen cardiologists do it. Do you know why they do it?
Click to expand...
No, but try to question a cardiologist and you'll get eviscerated post haste. I'm not saying it's right either. The first response was the commonly accepted one. I wanted to stir the pot, because I'd seen #2 before and I had a feeling WVU had as well.


Why so defensive about knowing all the ology?
Click to expand...
It was in jest Z. Thanks for the summary.
 
This is actually a great question and one that still remains un-answered. Comes up often in my program. Thanks OP. UTD has nothing to offer here either.

Out Pt we would just adjust warfarin. Why everyone goes F'ing nuts and changes things when someone is IP I have no idea. It's not like half these pt's walk further than the fridge at home compared to at the hosp....Most often I have seen attendings side with option 3.
 
#3 IF I am answering this question for a board exam

#1, #2, #3 all make sense for different pts. In real life, I'll probably make some assumptions and put this patient on "a need to bridge" spectrum. Then I call attn/cards/etc.. depending on who is managing, if spectrum is right-shifted. The response I get in order of frequency is usually: #1>>>#2>>#3.
 
I've since come to the conclusion that no LMWH is necessary UNLESS the patient has been noncompliant. And then it is necessary as risk for clotting actually goes up when Coumadin is initiated. That makes the most sense to this hilljack...
 
Is the patient currently in Afib? They could be on warfarin because they had a run of it after surgery or during a hospital stay (e.g. paroxysmal or persistent AFIB).. if they are not currently in AFIB their chances of throwing a clot are very small.. I would say you could just adjust the warfarin to reach your 2-3 goal and not bridge... or just add DVT prophylaxis until they reach their goal... If they are currently in Afib then of course, I would "rebridge"
 
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