Warfarin Institute of America
DEDICATED TO YOUR HEALTH SINCE 2000
BRIDGING THERAPY WHEN WARFARIN (Coumadin, Jantoven) MUST BE STOPPED
IT MUST BE NOTED THAT THE US FDA HAS NEVER GIVEN APPROVAL TO USING ANY HEPARIN OR LOW MOLECULAR WEIGHT HEPARIN AS A BRIDGE THERAPY WHEN WARFARIN MUST BE STOPPED.
Low molecular weight heparins available in the United states include enoxaparin (Lovenox®) dalteparin (Fragmin®) and tinzaparin (Innohep®) There may be others including ardeparin, fraxiparin, bemiparin and nadroparin available in some ot
her countries.
Bridging therapy refers to using either unfractionated heparin (UFH) or low molecular weight heparin (LMWH) when warfarin (Coumadin, Jantoven) must be stopped for surgery or some type of procedure.
UFH has been used for more than fifty years. Because of this, many physicians believe that it has been studied and proven safe or even approved for this use. This is not the case. There has never been and probably never will be a definitive study on this therapy. The only justification for doing this is "we have always done it that way." In fact, the risk of bleeding is probably higher with UFH than LMWH.
There was a poorly done study reported in 2002 that some pregnant women with mechanical heart valves in Africa died from clotting while using enoxaparin. The fault with the study was that this is a weight-based dosing plan and the women did not have their doses adjusted upward as their pregnancy advanced. The study probably should never have been attempted. As a result of this, there was near hysteria against using enoxaparin in any person with a mechanical heart valve. This was a case of overreaction.
There are four possible scenarios for people taking warfarin and facing a procedure or surgery that will require stopping warfarin.
- Stop warfarin with no bridging. and no complications
- Stop warfarin with bridging and no complications
- Stop warfarin with bridging and complications
- Stop warfarin with no bridging and complications
Group 1 has the best outcomes but at a high risk of complications
Group 2 has outcomes similar to group 1.
In group 3 it seems that the complications arise mostly from overdoses of the heparin product after surgery. The most serious complication seems to be a heart attack.
In group 4 the most serious complication for people with atrial fibrillation and mechanical heart valves appears to be a stroke.
Since the recovery from a heart attack is usually better than the outcome from a stroke, group 3 people fare better than those in group 4.
It comes down to making the decision to go for all or nothing (groups 1 and 4) or to settle for neither the best nor the worst outcomes (groups 2 and 3).
ASSESSING THE RISK OF STROKE FOR PEOPLE WITH ATRIAL FIBRILLATION
CHADs 2 Score
Condition Points
Prior Stroke/TIA 2
Congestive Heart Failure 1
Hypertension 1
Diabetes 1
Age > 75 Years 1
Total _______
DECIDING WHETHER OR NOT TO BRIDGE IN PEOPLE WITH ATRIAL FIBRILLATION
Risk Level Characteristics Bridging
High Stroke < 3 months ago Strongly Recommended
Rheumatic Mitral Disease
CHADs 2 Score 5 or 6
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Moderate CHADs2 Score 2 to 4 Consider
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Low CHADs2 Score <2 Optional
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DECIDING WHETHER OR NOT TO BRIDGE IN PEOPLE WITH MECHANICAL HEART VALVES
Risk Lev el Characteristics Bridging
High Stroke < 3 months ago Strongly Recommended
Any Mitral Valve
Aortic Caged Ball Valve
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Moderate Bileaflet Aortic AND Consider
≥ 2 Stroke Risk Factors
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Low Bileaflet Aortic AND
0 to 1 Stroke Risk Factors Optional
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DECIDING WHETHER OR NOT TO BRIDGE WHEN THE RISK IS FOR VENOUS THROMBOEMBOLISM (VTE)
Risk Level Characteristics Bridging
High VTE < 1 month ago Strongly Recommended
Active Cancer
Antiphospholipid Syndrome
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Moderate VTE < 6 months ago Consider
Prior Post-op DVT
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Low None of the above Optional
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ASSESSING THE RISK OF BLEEDING
Very High Risk
Procedure Warfarin LMWH
Irtracranial Surgery Start 1 to 2 days Start > 72 hours
Spinal Surgery Post-op post-op if at all
Coronary Artery Bypass
Valve replacement
High Risk
Procedure Warfarin LMWH
Major Blood Vessel Start evening of Start 48 – 72 hours
Permanent Pacemaker surgical day post-op
Internal Defibrillator
Prostatectomy
Bladder Tumor
Lung Removal
Total Knee
Total Hip
Intestinal Anastomosis
Bowel Polypectomy
Kidney Biopsy
Prostate Biopsy
Cervical Cone Biopsy
Moderate Risk
Procedure Warfarin LMWH
Other Abdominal Start evening of Start 24 – 48 hours
Other Chest surgical day post-op.
Other Orthopedic
Dental* Please Click Here For More Information
Low Risk
Procedure Warfarin LMWH
Cataract Start evening of Start 24 hours post-op
Most skin surgical day
Gall Bladder
Hernia Repair
Dental* Please Click Here For More Information
Uremia, thrombocytopenia, coagulation factor deficiencies, active peptic ulcer and a recent bleeding episode are non-quantified risk factors for bleeding. If any of these are present, it is probably justifiable to move the bleeding risk up to the next higher category (i.e. low to moderate etc.).
WHEN TO STOP WARFARIN PRIOR TO THESE PROCEDURES
5 days if the last INR was 2.0 to 3.0
6 days if the last INR was 3.5 or higher
6 days for people taking 3 mg or less
Check the INR the day before surgery. An INR ≤ 1.4 is acceptable.
If the INR is ≥ 1.5 give vitamin K 2.5 mg orally and recheck just prior to surgery
PERIOPERATIVE LMWH
Start second day after warfarin is stopped
No doses within 24 hours before surgery or procedure
Anti Xa levels are not necessary
Post-op dose can be the same as the pre-op dose. Some prefer to give ½ of the pre-op dose and start sooner.
Continue 3 to 5 days. By this time the INR should be near normal and not increase the risk of bleeding.
REFERENCES
Gage BF et al JAMA 2001;285:2864-70
www.acforum.org/admin/flashnews/monograph_on_bridging_therapy.pdf
O'Donnell MJ, Kearon C, Johnson J, Robinson M, Zondag M, Turpie I, Turpie AG. Brief communication: Preoperative anticoagulant activity after bridging low-molecular-weight heparin for temporary interruption of warfarin.Ann Intern Med. 2007 Feb 6;146(3):184-7.
Annals of Internal Medicine. Summaries for Patients. Safety of Surgery during Bridging Anticoagulation Therapy with Low-Molecular-Weight Heparin. 6 February 2007. Volume 146; Issue 3. Page I-35.
The assistance of Sean Fitzpatrick, Pharm D. Candidate at The University of Colorado Health Sciences Center, School of Pharmacy in preparing this page is recognized.
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Last updated February 12, 2007