Peri-operative management of anticoagulation

1. Peri-operative management of anticoagulation Marc Carrier MD, MSc FRCPC Assistant Professor, University of Ottawa Associate Scientist, Ottawa Health Research Institute

2. Today • Peri-operative bridging • Warfarin • ASA • Clopidogrel • Post-operative Thromboprophylaxis • Orthopedic surgery • General surgery

3. Peri-op bridging(warfarin)

4. Dilemma:Pre and Post-op Risk assessment Preventable thromboembolism Major bleeds

5. Pharmacokinetics • INR will normalise in a time period ranging from 50 to over 200 hours but 23% remain higher than 1.2 five days after d/c OACs

6. INR after warfarin induction • When reinitiated a therapeutic level of anticoagulation will be achieved in a variable time period ranging from 2 to 10 days • When OACs are discontinued and re-initiated the length of time with sub-therapeutic INRs is highly variable • As a consequence clinicians need to consider “bridging therapy”

7. Assessment of Thrombosis Risk • Venous Vs Arterial Thrombosis

8. Arterial Thrombosis – High risk

9. Risk of Bleeding from Procedure • Low Risk Procedure • Dental procedure • Skin Biopsy • Cataract surgery • GI: • Diagnostic colonoscopy or endoscopy • EGD +/- biopsy • Flexible Sphincteromy+/- biopsy • Biliary/pancreatic stent • ERCP without sphincterotomy • Moderate or High risk

10. STOP STOP STOP

11. Bridging with LMWH OR D -5 D5-10 Clinic Home X Local lab

12. Summary(pre-op) • Stop warfarin 5 days before surgery • Assess need for peri-operative bridging • High risk: Therapeutic LMWH > IV UFH • Moderate risk: Therapeutic > prophylactic LMWH > IV UFH • Low risk: no bridging or prophylactic LMWH • If therapeutic LMWH is used: • 50% therapeutic dose on OR day -1 • No need to follow anti-Xa levels • If prophylactic LMWH is used: • Last dose 24 hours before OR • If IV UFH is used: Stop infusion 4 hours pre-op • STAT INR 1-2 days before OR day • If INR > 1.5 give 1-2 mg of PO vitamin K

13. Summary(post-op) • Resume VKA 12 to 24 hours post op • Good hemostasis • PO intake • Epidural is out • Resuming Post-op LMWH bridging is • POD1 if good hemostasis • If using therapeutic doses of LMWH/UFH • POD1 if minor surgical procedure • Consider resuming on POD2 if high bleeding risk major surgery • No need to follow anti-Xa • D/C LMWH or UFH once INR therapeutic • i.e. > 2.0 or 2.5 depending on indication

14. Peri-op bridging(ASA, clopidogrel)

15. ASA/Clopidogrel • If not high risk for cardiac events: • Stop 7 to 10 days before the procedure • Resume on POD1 (24 hours post-op) • Adequate hemostasis • If high risk of cardiac events (exclusive of coronary stents) for non-cardiac surgery • Continue aspirin • Hold clopidogrel at least 5 days and preferable within 10 days of surgery • If high risk of cardiac events (exclusive of coronary stents) for CABG • Same as above • If ASA is interrupted then needs to be reinitiated between 6 and 48 hours after CABG

16. ASA/Clopidogrel • Coronary stent • If bare metal coronary stent within 6 weeks • Continue ASA and clopidogrel peri-operatively • If drug-eluting stent within 12 months • Continue ASA and clopidogrel peri-operatively • In patients with coronary stents who have interruption of ASA or clopidogrel • No need to routinely bridge these patients

17. Prevention of Venous Thromboembolism

18. General Principles • Should think about thromboprophylaxis for every patients • Mechanical methods alone in patients at high risk of bleeding only! • May be used as an adjunct to anticoagulant • The use of ASA alone as thromboprophylaxis is not recommended for any patient group!

19. What is the risk?

20. Risk factors for VTE

21. General Surgery • Low-risk general surgery patients undergoing minor procedure • No need for thromboprophylaxis • Early and frequent ambulation • Moderate-risk general surgery patients who are undergoing a major procedure for benign disease • LMWH, IFH sc TID or BID, or fondaparinux • Higher-risk general surgery patients who are undergoing a major procedure for cancer • LMWH, UFH sc TID or fondaparinux • Continue thromboprophylaxis until discharge except: • Cancer patients: at least 7 to 10 days • Cancer patients + other risk factors: up to 28 days

22. General Surgery • Entirely laparoscopic surgery procedure with no additional thromboembolic risk factors • No need for thromboprophylaxis • Early and frequent ambulation • If additional VTE risk factors then thromboprophylaxis until D/C home (unless cancer)

23. Orthopedic Surgery • LMWH • Prophylactic doses • Dalterapin 5000 IU OD, enoxaparin 40 mg OD or 30 mg bid, tinzaparin 4500 IU OD • Starting on POD1 • Fondaparinux (2.5 mg started 6 to 24 hours post-op) • Warfarin • target INR 2.0-3.0 • Rivaroxaban • 10 mg OD • Dabigatran • 220 or 150 mg OD • Not ASA, mechanical methods alone, dextran, or UFH

24. Duration • THR, TKR or HFS: • At least 10 days • THR, HFS: • Thromboprophylaxis should be extended beyond 10 days and up to 35 days • TKR: • Can consider extending thromboprophylaxis beyond 10 days and up to 35 days • Knee arthroscopy: • No need for thromboprophylaxis if no other VTE risk factors • If other risk factors, consider LMWH

25. Trauma • Thromboprophylaxis if possible • LMWH alone • LMWH + mechanical methods • Hold LMWH if high risk of bleeding • Don’t forget to resume… • No screening U/S for DVT • No IVC filter insertion as thromboprophylaxis • Continue thromboprophylaxis until hospital D/C • If patient undergoes inpatients rehab: • Switch to warfarin (target 2.0-3.0) until D/C home • Or continue LMWH prophylaxis

26. Thank You