1. Bridging Anticoagulation
UC Irvine Medical Center
05/2018
Danielle Wang

2. Objectives
Understand the clinical importance of decisions regarding management of perioperative anticoagulation
Understand how to stratify a patient’s thromboembolic risk
Become familiar with how to estimate a patient’s perioperative bleeding risk
Understand how to weigh thromboembolic risk and bleeding risk when deciding whether to bridge anticoagulation

3. Introduction
Over 35 million prescriptions for oral anticoagulation are written each year in the United States
Each year, 15% to 20% of patients on oral anticoagulation undergo invasive procedures or surgeries that interrupts their anticoagulation
Interruption of anticoagulation places patients at increased risk for thromboembolism, hemorrhage, and death
Compared with uninterrupted warfarin, bridging anticoagulation also correlates with increased hospital costs
Periprocedural anticoagulation management is a common clinical dilemma
Rechenmacher, SJ; Fang, JC. Bridging Anticoagulation: Primum Non Nocere. Journal of the American College of Cardiology 2015; 66:12.

4. Step 1: Confirm the indication for chronic oral anticoagulation
Why was anticoagulation originally prescribed?
Is anticoagulation still appropriate?
For example, a patient on warfarin that was originally prescribed for a single provoked DVT 1 year ago may not require continued anticoagulation

5. Step 2: Estimate the thromboembolic risk
Three risk groups:
Mechanical Heart Valves
Atrial Fibrillation
Venous Thromboembolism
Within each risk group, further stratify into:
High, Moderate, or Low Risk
Suggested management per UCI Hospitalist Program 2016: Team H curriculum

6. (Step 2: Estimate the thromboembolic risk - cont’d)
Stratifying thromboembolic risk for Mechanical Valves (MV)
High Risk:
Older model such as cage-ball or tilting disc Aortic Valve
Mitral Valve replacement
Moderate Risk:
Atrial Valve Replacement with risk factors
Risk Factors include: Prior CVA/TIA, HTN, DM, CHF, Afib, age >75, EF<30%, LV thrombus
Low Risk
Bi-leaflet tilt valve
Atrial Valve Replacement without risk factors (listed above)
Suggested management per UCI Hospitalist Program 2016: Team H curriculum

7. (Step 2: Estimate the thromboembolic risk - cont’d)
Stratifying thromboembolic risk for Atrial Fibrillation
High risk:
CHADSVASC 6-9
CVA / TIA < 3 months ago
Moderate Risk:
CHADSVASC 4-5
Low Risk:
CHADSVASC 1-3
Suggested management per UCI Hospitalist Program 2016: Team H curriculum

8. (Step 2: Estimate the thromboembolic risk - cont’d)
Stratifying thromboembolic risk for VTE
High risk:
< 1 month ago
Unprovoked < 3 months ago
Persistent < 6 months ago
Moderate Risk:
Provoked 1-3 months ago
Unprovoked 3-6 months ago
Persistent 6-12 months ago
Low Risk:
Provoked > 3 months ago
Unprovoked > 6 months ago
Persistent >12 months ago
Suggested management per UCI Hospitalist Program 2016: Team H curriculum

9. Step 3: Estimating perioperative bleeding risk
High or Low Bleeding risk based on Procedure Type
High Risk (two-day risk of major bleed 2-4%)
Any major operation >45 min
AAA repair
CABG
Endoscopic FNA
Heart valve replacement
Hip / knee Replacement
Renal biopsy
TURP, Urological surgery
Vascular / Neurosurgical / Head and neck surgery
Adapted from research originally published in Blood. Spyropoulos AC, Douketis JD. How I treat anticoagulated patients undergoing an elective procedure or surgery. Blood 2012; 120:2954. Copyright © 2012 the American Society of Hematology.
If in doubt, ask the operative service performing the procedure

10. Step 3: Estimating perioperative bleeding risk
High or Low Bleeding risk based on Procedure Type
Low Risk (two-day risk of major bleed 2-4%)
Any major operation >45 min
AAA repair
CABG
Endoscopic FNA
Heart valve replacement
Hip / knee Replacement
Renal biopsy
TURP, Urological surgery
Vascular / Neurosurgical / Head and neck surgery
Adapted from research originally published in Blood. Spyropoulos AC, Douketis JD. How I treat anticoagulated patients undergoing an elective procedure or surgery. Blood 2012; 120:2954. Copyright © 2012 the American Society of Hematology.
If in doubt, ask the operative service performing the procedure

11. Step 4: weighing risks and benefits
Weigh the patient’s thromboembolic risk against perioperative bleeding risk

12. Suggested perioperative management of anticoagulation
Suggested management per UCI Hospitalist Program 2016: Team H curriculum
-High/Moderate risk mechanical valve (MV): older model, Mitral valve replacement, Atrial valve replacement (AVR) with risk factors
-Low risk MV: bi-leaflet tilt valve, AVR without risk factors (no Afib, EF>30%, no LV thrombus)
-High risk Atrial fibrillation (AF): CHADSVASC 6-9, CVA/TIA<3mo
-Moderate risk AF: CHADS-VASC 4-5
-Low risk AF: CHADSVASC 1-3
-High Risk Venous thromboembolism (VTE): < 1month ago, unprovoked <3 months, persistent <6 months
-Moderate Risk VTE: provoked 1-3 months, Unprovoked 3-6 months, persistent 6-12 months
-Low risk VTE: provoked >3 months, Unprovoked 3-6 months, Persistent >12 months

13. Example Case
A 76-year-old female with non-valvular atrial fibrillation, hypertension, and prior stroke three months ago, on warfarin, requires elective hip replacement.
How do we manage her anticoagulation?
Step 1: Anticoagulation Indication = Afib
Step 2: Stratify thromboembolic risk - Afib with CHADSVASC 6 = High thromboembolic risk
Step 3: Perioperative bleeding risk - Hip replacement = High Bleeding Risk
Step 4: Weighing Risks and Benefits = Bridge with LMW Heparin

14. Summary
Management of perioperative anticoagulation is a common and important clinical scenario
The decision to bridge anticoagulation is based on weighing a patient’s thromboembolic risk against perioperative bleeding risk
Further resources:
Rechenmacher, SJ; Fang, JC. Bridging Anticoagulation: Primum Non Nocere. Journal of the American College of Cardiology 2015; 66:12.