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

Today Peri-operative bridging –Warfarin –ASA –Clopidogrel Post-operative Thromboprophylaxis –Orthopedic surgery –General surgery

Peri-op bridging (warfarin)

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

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

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”

Assessment of Thrombosis Risk Venous Vs Arterial Thrombosis

Arterial Thrombosis – High risk CHADS2 Congestive Heart Failure 1 Hypertension1 Age >701 Diabetes1 Stroke/TIA2 Total 0-2: %/yr stroke > 2: %/yr stroke

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

Bleeding risk→ Thrombosis Risk↓ LowHigh Low High Bridge STOP

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

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

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

Peri-op bridging (ASA, clopidogrel)

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

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

Prevention of Venous Thromboembolism

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!

What is the risk?

Risk factors for VTE

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

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)

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 Rivaroxaban –10 mg OD Dabigatran –220 or 150 mg OD Not ASA, mechanical methods alone, dextran, or UFH

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

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 ) until D/C home Or continue LMWH prophylaxis

Thank You