WARFARIN: TO BRIDGE OR NOT

TO BRIDGEJenny Chan

University of WashingtonPharmD Candidate c/o 2015Providence Ambulatory Care

Clinics10/30/14

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ROADMAP 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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WHO SHOULD RECEIVE BRIDGING? High Risk Patients: Yes Moderate Risk Patients: Maybe NOT Low Risk Patients: No

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RISK STRATIFICATION AND RECOMMENDATIONS FOR BRIDGE THERAPY—HIGH RISK

UWMC Anticoagulation Clinic Feb 2014. http://depts.washington.edu/anticoag/home/content/risk-stratification-and-recommendations-bridge-therapy

*Recommend checking with vascular department for PVD patients.

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RISK STRATIFICATION AND RECOMMENDATIONS FOR BRIDGE THERAPY—MODERATE RISK

UWMC Anticoagulation Clinic Feb 2014. http://depts.washington.edu/anticoag/home/content/risk-stratification-and-recommendations-bridge-therapy

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RISK STRATIFICATION AND RECOMMENDATIONS FOR BRIDGE THERAPY—LOW RISK

UWMC Anticoagulation Clinic Feb 2014. http://depts.washington.edu/anticoag/home/content/risk-stratification-and-recommendations-bridge-therapy

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CHEST 2012 GUIDELINES FOR BRIDGING IN MODERATE RISK PATIENTS 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.

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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CHEST 2012 MODERATE RISK PATIENTS WITH HIGH RISK FACTORS 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.”

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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2014 AHA/ACC VALVULAR HEART DISEASE GUIDELINES ON BRIDGING FOR PROSTHETIC VALVES 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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2014 AHA/ACC VALVULAR HEART DISEASE GUIDELINES ON BRIDGING FOR PROSTHETIC VALVES 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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2014 AHA/ACC VALVULAR HEART DISEASE GUIDELINES ON BRIDGING FOR PROSTHETIC VALVES

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BRIDGING WITH LMWH NOT RECOMMENDED HIGH BLEEDING RISK PROCEDURES

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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BRIDGING FOR MINOR PROCEDURESProcedure Bridging

recommendationLOW 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

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BRIDGING FOR MINOR PROCEDURESDental Procedures Bridging

RecommendationMODERATE 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.

*UWMC Anticoagulation Clinic. http://depts.Washington.edu/anticoag/home/content/suggestions-anticoagulation-management-and-after-dental-procedures

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BRIDGING FOR CARDIAC DEVICE PLACEMENT 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.

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.

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ANTICOAGULATION FOR CARDIOVERSION 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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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

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CHEST 2012 GUIDELINES FOR MANAGING 1 OUT-OF-RANGE INR 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).

Holbrook A, Schulman S, Witt DM, et al. Evidence-Based Management of AnticoagulantTherapy. Chest. 2012;141(2_suppl):e152S-e184S. doi:10.1378/chest.11-2295.

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IS BRIDGING NECESSARY FOR 1 SUBTHERAPEUTIC INR? 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).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.

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IS BRIDGING NECESSARY FOR 1 SUBTHERAPEUTIC INR?

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.

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IS BRIDGING NECESSARY FOR 1 SUBTHERAPEUTIC INR? 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.

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.

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THINK BEFORE YOU BRIDGE! High Risk Patients: Yes Moderate Risk Patients: Maybe NOT Low Risk Patients: No