1. Jenny Chan
University of Washington
PharmD Candidate c/o 2015
Providence Ambulatory Care Clinics
10/30/14

2.  Risk stratification (high, moderate, low)
 In-depth review of moderate risk literature
 High risk bleeding procedures
 Bridging for minor procedures?
 Cardioversion/Cardiac device implantation
 Bridging for 1 Subtherapeutic INR?
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3.  High Risk Patients: Yes
 Moderate Risk Patients: Maybe NOT
 Low Risk Patients: No
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4. UWMC Anticoagulation Clinic Feb 2014.
http://depts.washington.edu/anticoag/home/content/risk-stratification-and-recommendations-bridge-therapy
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*Recommend checking with vascular department for PVD patients.

5. UWMC Anticoagulation Clinic Feb 2014.
http://depts.washington.edu/anticoag/home/content/risk-stratification-and-recommendations-bridge-therapy
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6. UWMC Anticoagulation Clinic Feb 2014.
http://depts.washington.edu/anticoag/home/content/risk-stratification-and-recommendations-bridge-therapy
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7.  Bridging may be considered in the following
patients for procedures at moderate risk of
bleeding (Grade 2C)
 Patients with mechanical bileaflet aortic valve and
additional stroke risk factors
 Patients with Afib and a CHADS2 score of 3 or 4 or
prior thromboembolism during VKA interruption
 Patients with VTE within past 3-12 months,
nonsevere thrombophilia, active cancer and
recurrent VTE.
 No bridging may be considered for major cardiac
surgery and carotid endarterectomy surgery due to
high bleeding risk.
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Douketis et al. Perioperative Management of antithrombotic therapy.
Chest [Internet]. 2012 Feb [cited 2014 Oct 22]. 141(2 Suppl):e326S-50S. doi: 10.1378/chest.11-2298

8.  Example 1: “A perceived high-risk patient
group may also include those with Afib, prior
stroke and one additional stroke risk factor
(CHF, HTN, age >75 years, diabetes mellitus,
prior stroke or TIA [CHADS2] score of 3.”
 Example 2: “A patient with remote (>1 year
ago), but severe VTE associated with
pulmonary hypertension would be classified
as low risk but may be perceived as high
risk.”
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Douketis et al. Perioperative Management of antithrombotic therapy.
Chest [Internet]. 2012 Feb [cited 2014 Oct 22]. 141(2 Suppl):e326S-50S. doi: 10.1378/chest.11-2298

9.  Temporary interruption of warfarin, without bridging is
recommended for patients with a *bileaflet mechanical AVR and
no other risk factors for thrombosis who are undergoing invasive
or surgical procedures (Class IC)
 Bridging is recommended for patients undergoing invasive or
surgical procedures if (Class IC)
 Mechanical AVR and any thromboembolic risk factor
 Thromboembolic risk factors
 Atrial fibrillation
 Previous thromboembolism
 Hypercoagulable condition
 Older-generation mechanical valves
 LV systolic dysfunction (LVEF< 30%)
 >1 mechanical valve
 Older-generation mechanical AVR (caged-ball or tilting disk)
 *Consult cardiologist if unsure about the type of heart valve.
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10.  Stop VKA 2 to 4 days before the procedure
(so INR falls to <1.5 for major surgical
procedures). (Grade 1C)
 CHEST Guidelines 2012 recommends stopping
VKA 5 days before procedure (Grade 1B).
 IV unfractionated heparin or subQ LMWH is
started when INR <2.0 and stopped 4-6 hours
(for IV UFH) or 12 hours (subQ LMWH) before
procedure. Use therapeutic weight-adjusted
LMWH dosing.
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11. 11

12. Cardiovascular Surgeries Noncardiovascular Surgeries
 Cardiac surgery (CABG,
PCI, heart transplant,
heart valve replacement,
carotid endareterectomy,
etc.)
 Pacemaker or implantable
cardioverter-defibrillator
device (ICD) implantation*
 Urologic surgery and
procedures
 Intracranial or spinal surgery
 Colonic polyp resection
 Surgery in highly vascular
organs (kidney, liver, spleen)
 Bowel resection
 Major surgery with extensive
tissue injury (cancer surgery,
joint arthroplasty,
reconstructive plastic surgery)
 Laminectomy
 Thyroid surgery
Douketis et al. Perioperative Management of antithrombotic therapy. Chest [Internet].
2012 Feb [cited 2014 Oct 22]. 141(2 Suppl):e326S-50S. Doi: 10.1378/chest.11-2298
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13. 13
Procedure Bridging recommendation
LOW BLEEDING RISK
Minor dental procedures
• 1 tooth extraction
• Routine cleaning
• Endodontic (root canal)
procedures
Either continue warfarin at normal
dose or stop 2-3 days before the
procedure. 2012 CHEST guidelines also
recommend the use of a prehemostatic
agent such as tranexamic acid with the
continuation of warfarin (Grade 2C)
Cataract surgery Continue warfarin at normal dose
(Grade 2C)
• Clinically important bleeding <3%
Minor dermatological
procedures
Continue warfarin at a normal dose
(Grade 2C)
Douketis et al. Perioperative Management of antithrombotic therapy.
Chest [Internet]. 2012 Feb [cited 2014 Oct 22]. 141(2 Suppl):e326S-50S. doi: 10.1378/chest.11-2298

14. Dental Procedures Bridging Recommendation
MODERATE BLEEDING RISK*
• Subgingival scaling
• Restorations with subgingival
preparations
• Standard root canal
Interruption of warfarin
therapy is not necessary. Use
local measures to prevent or
control bleeding.
HIGH BLEEDING RISK*
• Multiple extractions
• Apicoectomy (root removal)
• Alevolar surgery (bone
removal)
May need to reduce INR or
return to normal hemostasis.
Use local methods to prevent
or control bleeding.
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*UWMC Anticoagulation Clinic. http://depts.Washington.edu/anticoag/home/content/suggestions-
anticoagulation-management-and-after-dental-procedures

15.  Pacemaker or ICD placement RCT Trial
 Moderate to high risk patients
 338 patients assigned heparin bridging (326 underwent
surgery)
 343 assigned to continued warfarin (335 underwent
surgery)
 Clinically significant hematoma
 Heparin bridging: 54 (16%)
 Warfarin continuation: 12 (3.5)
 Relative risk: 0.19 (95% CI: 0.10-0.36)
 Guidelines recommend bridging for pacemaker or ICD
placement for high risk patients but studies show this
may not be necessary because the risk of bleeding may
outweigh the risk of thromboembolism.
15
Birnie et al. Pacemaker or Defibrillator Surgery without Interruption of Anticoagulation. N Engl J Med [Internet].
2013 May 30 [cited 2014 Oct 22]. 30;368(22):2084-93. doi: 10.1056/NEJMoa1302946.

16.  Patients who will undergo cardioversion need
to undergo full anticoagulation for ___ weeks
before procedure and for ____ weeks after
procedure. (Grade 1B)
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3
4
You JJ, Singe DE, Howard PA, et al. Antithrombotic therapy for Atrial Fibrillation. Chest [Internet].
2012; 141(2_suppl):e531S-e575S. doi:10.1378/chest.11-2304

17.  For patients taking VKAs with previously stable
therapeutic INRs who present with a single out-
of-range INR of ≤ 0.5 below or above
therapeutic, we suggest continuing the current
dose and testing the INR within 1 to 2
weeks (Grade 2C).
 For patients with stable therapeutic INRs
presenting with a single subtherapeutic INR
value, we suggest against routinely
administering bridging with heparin (Grade 2C).
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Holbrook A, Schulman S, Witt DM, et al. Evidence-Based Management of Anticoagulant
Therapy. Chest. 2012;141(2_suppl):e152S-e184S. doi:10.1378/chest.11-2295.

18.  Retrospective chart review in 710 patients
found 546 episodes of isolated
subtherapeutic INR in 320 patients at a
pharmacist-managed ACC.
 Subtherapeutic INR was preceded by 2
INRs within or above range.
 18% of all subtherapeutic INR episodes (98
episodes) were bridged with parenteral
agents (enoxaparin, fondaparinux).
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Hwang JM, Taylor TN, Sharma KP, Clemente JL, Garwood CL. Bridging for an isolated subtherapeutic INR: an
Evaluation of clinical practice patterns, outcomes and costs from an anticoagulation clinic.
J Thromb Thrombolysis (2012). 33:28-37. DOI 10.1007/s11239-011-0643-0.

19. 19
Hwang JM, Taylor TN, Sharma KP, Clemente JL, Garwood CL. Bridging for an isolated subtherapeutic INR: an
Evaluation of clinical practice patterns, outcomes and costs from an anticoagulation clinic.
J Thromb Thrombolysis (2012). 33:28-37. DOI 10.1007/s11239-011-0643-0.

20.  Bridged vs Non-bridged
 Bruising (18.4% vs 3.6%)
 Minor bleed (4.1% vs 3.1%)
 Major bleed (2% vs 1.3%)
 Thrombosis (2% vs 0.7%)
 2 in bridged episodes
 3 in non-bridged episodes
 Bridging is associated with
more bruising and required
more follow-up in clinic and
placed a greater medical
cost burden on the patient
so the authors suggest that
bridging is of little benefit
to the patient.
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Hwang JM, Taylor TN, Sharma KP, Clemente JL, Garwood CL. Bridging for an isolated subtherapeutic INR: an
Evaluation of clinical practice patterns, outcomes and costs from an anticoagulation clinic.
J Thromb Thrombolysis (2012). 33:28-37. DOI 10.1007/s11239-011-0643-0.

21.  High Risk Patients: Yes
 Moderate Risk Patients: Maybe NOT
 Low Risk Patients: No
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