Peri-operative management of anticoagulation

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Peri-operative management of anticoagulation

• Marc Carrier MD, MSc FRCPC
• Assistant Professor, University of Ottawa
• Associate Scientist, Ottawa Health Research
  Institute

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Today

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

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Peri-op bridging(warfarin)
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DilemmaPre and Post-op Risk assessment
Preventable thromboembolism
Major bleeds
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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

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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

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Assessment of Thrombosis Risk

• Venous Vs Arterial Thrombosis

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Arterial Thrombosis High risk
CHADS2 CHADS2
Congestive Heart Failure 1
Hypertension 1
Age gt70 1
Diabetes 1
Stroke/TIA 2
Total
0-2 1.5-2.5/yr stroke gt 2 4.0-18.2/yr stroke 0-2 1.5-2.5/yr stroke gt 2 4.0-18.2/yr stroke
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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

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Bleeding risk? Thrombosis Risk? Low High
Low
High Bridge
STOP
STOP
STOP
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Bridging with LMWH
OR
D -5
D5-10
Clinic
Home
X
Local lab
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Summary(pre-op)

• Stop warfarin 5 days before surgery
• Assess need for peri-operative bridging
• High risk Therapeutic LMWH gt IV UFH
• Moderate risk Therapeutic gt prophylactic LMWH gt
  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 gt 1.5 give 1-2 mg of PO vitamin K

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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. gt 2.0 or 2.5 depending on indication

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Peri-op bridging(ASA, clopidogrel)
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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

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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

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Prevention of Venous Thromboembolism
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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!

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What is the risk?
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Risk factors for VTE
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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

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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)

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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

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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

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Trauma

• Thromboprophylaxis if possible
• LMWH alone
• LMWH mechanical methods
• Hold LMWH if high risk of bleeding
• Dont 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

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Thank You